Sensory Integration parte 02

 

96 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

to identify food, members of other species, and

familiar or unfamiliar members of our own

species” ( Zigmond, Bloom, Landic, Roberts, &

Squire, 1999 , p. 821); this global function has not

changed. The visual system functions primarily

as an edge, contrast, and movement detector. We

perceive visual images best when they are still;

therefore, our visual abilities depend, in part, on

the vestibular-ocular refl ex, which contributes to

a stabilized visual fi eld. The visual system itself

can adjust to movement within the environment

with the optokinetic refl ex, which works with the

vestibulo-ocular refl ex to maintain a stable image

on the retina. When disparity exists between

visual and other sensory inputs—for instance,

when we sit in a still car while the car-wash

apparatus moves forward and backward over the

surface—we get the visual impression that the

car is moving, although vestibular and proprioceptive inputs tell us otherwise. Nonetheless, we

believe the visual system and are likely to press

on the brake pedal to stop us from “moving.”

 Visual processing involves at least three parallel pathways carrying information that must

be integrated. Next, we will present a greatly

simplifi ed examination of structures and mechanisms underlying vision, beginning with a

description of receptors, transduction, and visual

pathways. We close with a brief consideration

of function. Keep in mind that, within the visual

system, more than any other sensory system, the

whole is much greater than a mere summing of

the parts.

Receptors and Transduction

 Vision receptors are specialized cells located in

the neural retina at the back of the eye. These

photoreceptors, the rods and cones, transduce

light energy into electrical energy that can be

transmitted to the CNS ( Fig. 4-25 ). Cones are

responsible for day vision and rods for night

vision. Cones mediate color vision and provide

higher acuity than do rods, which are highly

light sensitive and able to amplify light signals

to enable vision in dim light. Although cone

pathways are not convergent, maintaining a

high degree of spatial resolution, rod pathways

converge extensively (which further increases

the ability to see in dim light by summing light

input), which decreases the resolution capability

of these receptors. In addition, rod cells respond

slowly, which adds to their ability to sum dim

light, allowing us to see in low-light conditions.

On the other hand, cones respond rapidly, which

allows us to see quick fl ashes of light.

 Cone cells are of three types, each responding to a different spectrum of color: red, green,

and blue. Differentiation of other colors depends

on differential transmission of information from

these three receptors. In contrast, rod cells are

achromatic—that is, they respond to all wavelengths of light, but they do not allow for discrimination of color. In the center of the retina is

an area called the fovea. In this region, light more

readily reaches the receptor cells, and acuity is

enhanced. There are no rods in the fovea, only a

dense concentration of cones.

 Transduction of light energy into the electrical signal needed to get information from receptor cells into the CNS is a complicated process.

However, a brief look at this process helps us

compare activity in this sensory system with that

in others. The process of changing light energy

into a neural signal begins with the rod and cone

cells. These cells maintain tonic activity and

transmit information to the CNS in an ongoing

manner through neurotransmitter release. With

a change in light or the detection of an edge or

movement, a change in tonic activity occurs,

either increasing or decreasing the amount of

neurotransmitter released, and subsequently

altering the ongoing signal to the CNS. Because

of the complexity of the retina, a great deal of

processing occurs in this neural structure before

the time when information is transmitted over

the optic nerve to the CNS.

 Retina

 The retina ( Fig. 4-25 ) has 10 layers. The outer

layer consists of the pigment epithelium. The

neural retina forms the remaining nine layers.

Light must travel through the outermost eight

layers of the retina before falling on the receptor

cells. Light hits the layers in this order:

 1. Inner limiting membrane

 2. Ganglion cell layer

 3. Inner plexiform (synapses between ganglion,

bipolar, and amacrine cells)

 4. Inner nuclear layer (bipolar, amacrine, and

horizontal cell bodies)

 5. Outer plexiform layer (synapses between

bipolar, horizontal, and receptor cells)

CHAPTER 4 Structure and Function of the Sensory Systems ■ 97

FIGURE 4-25 The retina consists of 10 cell layers, not all shown here. The photoreceptors (rods for low light

vision and cones for color and detail vision) are located in the fi nal cell layer. Shown in this fi gure are two other

cell types in the retina, bipolar and ganglion cells. Ganglion cell axons form the optic nerve.

Sclera

Choroid Pigment cells

Bipolar

neurons

Ganglion

neurons

Light waves

Cone

Rod

Optic nerve

Optic nerve

fibers

 6. Outer nuclear layer (cell bodies for receptor

cells)

 7. Outer limiting membrane

 8. Receptor layers (light sensitive receptor cell

processes)

 9. Pigment epithelium

 Receptor cells (rods and cones) synapse onto

bipolar cells found in the inner nuclear layer

and from there connect with ganglion cells

( Fig. 4-25 ), the axons of which form the optic

nerve. The optic nerve projects to the lateral

geniculate nucleus (LGN) of the thalamus and

the SC, termed the “pretectal area” in Figure

4-26 . Intervening in this process are interneurons

known as horizontal and amacrine cells, also

found in the inner nuclear layer. Although the

receptor cells activate bipolar cells, the horizontal and amacrine cells exert an inhibitory infl uence on receptor, bipolar, and ganglion cells. The

inhibition from horizontal cells is an example of

lateral inhibition and serves to sharpen the edges

98 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

of receptive fi elds, allowing for great accuracy in

the information that travels to the CNS. Although

bipolar cells work in a different manner, they

also serve to sharpen the edges of visual images.

 Ganglion cells can be grouped in two ways.

First, ganglion cells can be categorized by characteristics of the receptive fi eld associated with

the receptor cells. Using this approach, one class

of ganglion cell is activated by light directed at

the center of its receptor fi eld (on-center); another

is turned off by light directed at the center of its

receptor fi eld (off-center). Forming two parallel

routes to the CNS, the on-center and off-center

information affords the ability to detect contrast

in the visual image.

 A second means of categorizing ganglion cells

is based on size, connectivity, and properties;

each category will include on- and off-center

cells. Table 4-2 compares the various characteristics of the magnocellular and parvocellular cells.

 Understanding our visual world, then, is not

dependent solely on the absolute amount of light

available; we use light and dark contrast, as well

as edge detection and movement, for much of

this information. The bottom line with this highly

complex circuitry is that a great deal of information about contrast, color, form, and movement

in the visual environment is processed before

information reaches the CNS.

Central Connections

 Gangliar projections form the optic nerve. As can

be traced in Figure 4-25 , fi bers from the nasal

region of the retina cross at the optic chiasm

and join with fi bers from the temporal retina of

the opposite eye to form the optic tract, which

projects primarily to the LGN of the thalamus.

This is the fi rst of the three processing pathways for visual information that we will discuss.

The arrangement of fi bers projecting to the

LGN allows each hemisphere to receive visual

information from the contralateral half of the

visual world.

 A detailed organization of fi bers within the

optic nerve continues into the optic tract and then

is projected into the LGN. As with the tactile

system, the representation within the LGN

FIGURE 4-26 Visual information from the retina is transmitted by the ganglion cells in an organizational

manner based on visual fi eld. Fibers from the temporal half of the left retina join with fi bers from the nasal half

of the right retina, forming the left optic tract and projecting to the left thalamus. Similarly, left nasal and right

temporal retinal fi bers join to form the right optic tract and project to the right thalamus. This arrangement

provides the brain with information about left and right visual space, respectively. In the thalamus, the lateral

geniculate nuclei receive visual information, and project this on to the primary visual cortex, area 17. A

secondary visual pathway involves optic tract fi bers projecting to the superior colliculus.

Optic nerve

Optic chiasm

Lateral

geniculate body

Optic tract

Superior colliculus

Optic radiations

Primary visual cortex

(medial occipital lobe)

CHAPTER 4 Structure and Function of the Sensory Systems ■ 99

refl ects the size of the receptor fi eld in the

periphery. Thus, the fovea, which has the greatest number of receptor cells and the smallest

receptor fi elds, has the greatest area of representation in the LGN.

 Information from the LGN is projected to

the ipsilateral primary visual cortex, or area 17

( Fig. 4-7 ). Here magnocellular and parvocellular

pathways maintain their integrity, giving information about the “what” and “where” of visual

images. Cells in the primary visual cortex are

sensitive to the outline of an object but not to its

interior. They respond to the specifi c position of

an object as well as its axis or orientation. This

is why the visual system is sometimes referred to

as a contrast or edge detector.

 The organization of the visual cortex is highly

complex. Cells there form columns; neurons

within a single column respond to a single axis

or orientation. The columns are interrupted by

what have been called blob regions of cells that

are sensitive to color rather than axis. A third

level of organization within this cortical region

is a system of ocular dominance columns. These

columns receive input from either the left or

right eye, and they alternate at regular intervals,

leading to binocular vision.

 Visual perception depends on projections

beyond area 17. Parvocellular pathway projections run from area 17 to area 19 and then to the

inferior temporal region, where form and color

are perceived. Projections to the inferior temporal cortex result in interpretations of the “what”

of a visual image. This area of the brain is also

associated with face and shape recognition.

 Perception of motion has its origins in the responsivity of magnocellular ganglion cells in the

retina and their projections to the LGN, area 17,

area 18, and the middle or superior temporal

area. Visual signals, then, project to the visualmotor area of the parietal lobe. This pathway

carries information pertaining to the interpretation of speed and direction of object motion and

assists in determining where objects are.

 The second visual pathway begins with fi bers

from the optic tract projecting to the SC. Cells

here have large receptive fi elds and, as such, do

not interpret the specifi cs of the visual world.

Instead, these cells respond to horizontal movement within the visual fi eld. Other inputs to the

SC come from the visual cortex and the spinotectal pathway, the latter of which carries somatosensory information from both the spinal cord

and the medulla. Projections from the SC include

those to the thalamus and others to the spinal

cord via the tectospinal pathway. Other fi bers are

sent to the oculomotor nuclei. Thus, the SC plays

a role in the visual coordination of posture and

the control of eye movements.

 The smallest visual pathway is called the

accessory optic tract. Projections from the optic

tract are sent to small (i.e., accessory) nuclei

around the oculomotor nucleus, the medial vestibular nucleus, the LGN, and other regions of

the thalamus. The efferent processes from these

regions project largely to the inferior olive,

which sends projections to the vestibular component of the cerebellum. With these connections,

the accessory optic tract plays a role in oculomotor adaptation.

TABLE 4-2 Differentiating between Magnocellular and Parvocellular Cells

MAGNOCELLULAR (“WHERE”) PARVOCELLULAR (“WHAT”)

Size of receptor fi eld Large Small

Conduction of information Rapid Slower

Sensitive to Contrast, even when it is low Color; low contrast sensitivity

Response Brief Sustained

Main focus General features of objects

and object movement

Finer details of vision, spatial

orientation, including form and color

Area of projection in LGN Ventral layers 1 and 2 Dorsal layers 3 to 6

Liu, C.-S. J., Bryan, R. N., Miki, A., Woo, J. H., Liu, G. T., & Elliot, M. A. ( 2006 ). Magnocellular and parvocellular visual pathways have

different blood oxygen level–dependent signal time courses in human primary visual cortex. American Journal of Neuroradiology, 27,

1628–1634.

100 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

Visual Experience Counts

 Development of skills within the visual system

is dependent on experiences, both prenatally

and postnatally. Cooperation and competition of

axons from the same and opposite eye, respectively, are critical to the postnatal formation

of ocular dominance columns and, thus, depth

perception and binocular vision. Early studies

of visual deprivation, conducted by temporarily closing one eye at birth and then allowing

both eyes to see after a period of time, show

that deprivation during critical postnatal periods

results in blindness in the sutured eye even once

it was opened ( Hubel & Weisel, 1965 ). The

blindness was reversible only if closure was

short-lived ( Hubel, Weisel, & LeVay, 1977 ). For

instance, when congenital cataracts are present,

it is critical to remove them very early. Robb and

colleagues ( 1987 ) reported that the critical period

to reverse deprivation amblyopia (or “lazy eye”),

and achieve adequate acuity, involved removing

cataracts before the age of 17 months. Kandel

and colleagues ( 2013 ) indicated that cataracts

not removed until 10 or more years of age lead

to a permanent impairment of form perception,

although color perception remains intact. Other

incidences and studies of vision deprivation

support this fi nding. Because of its impact on the

connections among cortical cells, experience is

critical to the development of normal visual perception. We present more detailed information on

visual-spatial components of visual perception

in Chapter 7 (Sensory Discrimination Functions

and Disorders).

HERE ’ S THE POINT

 • Vision is our dominant sensory system; it is

responsible for edge, contrast, color, and

movement detection.

 • Changes in light in the environment activate

the receptors (rods and cones, found in the

retina), and a great deal of sensory processing

takes place in the retina itself, before neural

signals are sent to the brain.

 • Ganglion fi bers from the retina form the optic

nerve and project to the LGN of the thalamus;

different kinds of ganglion cells project to

different layers of the LGN. This arrangement

contributes to our understanding of “where”

(magnocellular ganglion cells) and “what”

(parvocellular ganglion cells) is in our visual

environment.

 • “Where” and “what” information is projected

from the LGN to the visual cortex, where

a complex organization of fi bers and cells

provides us with binocular vision and allows for

interpretation of object orientation and color.

 • Object identifi cation information (supporting

our interpretation of “what”) reaches the

inferior temporal lobe after passing through the

visual cortex, providing us with our perception

of object form and color; information related

to perception of object movement is sent to

middle and superior temporal lobes as well as

regions of the parietal lobe.

 • The role of the visual system in postural control

and eye movements is a function of projections

to the SC from the retina, visual cortex, and

spinotectal pathways and from the SC to the

thalamus and spinal cord.

 • Our ability to accurately interpret visual input

is experience dependent, and experiences must

take place within time-sensitive windows for

optimal function.

Gustation and Olfaction

 The last two sensory systems we will look at are

chemoreceptive systems, responding to chemicals in their specialized environments. They are

the oldest and considered the most primitive of

our sensory systems, in that they can be found

pervasively throughout evolution. Here we will

address gustation and olfaction. However, it is

important to note that many of the interoceptors,

addressed earlier, fall into the chemoreceptor

functional category, as do some nerve endings

in the skin and mucous membranes. We will

address the neuroscience of gustation (taste)

and olfaction (smell) individually because each

system has unique properties. Functionally these

two systems are closely linked; as such, we end

this section by looking at the relationship of taste

and smell to disorders related to the functional

tasks of eating and feeding.

Taste and Taste Receptors

 Taste is a mechanism by which we can distinguish between nutritious and noxious substances

in the mouth. It is generally agreed that we are

CHAPTER 4 Structure and Function of the Sensory Systems ■ 101

born to fi nd sweet tastes pleasant and bitter tastes

noxious, at least initially. Mothers’ milk is sweet,

and we are driven to seek this. Many poisons

carry a bitter taste, hence our natural tendency to

reject bitter substances. Experience plays a role

here, and we can become accustomed to bitter

tastes, as drinkers of coffee and beer well know.

 Taste is detected by taste cells, located on

taste buds, which are themselves located on

papillae on the tongue, soft palate, pharynx,

and upper part of the esophagus ( Fig. 4-27 ).

Most of us have between 2,000 and 5,000 taste

buds, each housing 50 to 150 taste cells. Each

taste cell responds best to one of fi ve specifi c

tastes (sweet, sour, salty, bitter, and umami or

savory), and papillae tend to be most sensitive

to a single taste. Thus, we often see the tongue

“mapped” for taste with sweet on the tongue tip,

salty on either side of sweet, sour on the sides

just posterior to salty, and bitter at the base of

the tongue. However, when tastes are presented

at higher concentrations, cells demonstrate less

selectivity for a single taste. The chemicals that

give food and beverages taste interact with taste

cells, where transduction into a neural signal

takes place. Information related to what we are

tasting, its concentration and qualities, is coded

by the taste cells and transmitted over sensory

neurons to the CNS. We have the capacity to

detect many different fl avors, far more than the

basic fi ve identifi ed here. This capacity is the

result of the complex chemical makeup of foods

and beverages activating various combinations

of taste cells to varying degrees. Coding then

is a crucial aspect of our broad-spectrum ability

to taste. Importantly, smell also plays a role in

our ability to detect fl avors, as does the way a

substance feels (texture, temperature, pain) in

the mouth.

Taste Pathways

 Taste afferents are divided among branches of

three cranial nerves: facial (VII), glossopharyngeal (IX), and vagus (X). Afferents from

all the nerves enter the medulla and project to

FIGURE 4-27 Taste cells are located on taste buds, here shown from the tongue. The taste pore is the opening

to the taste bud. Two different taste cells are shown in this fi gure, along with the basal cells. At the base of the

taste bud is the nerve fi ber that will conduct information about taste to the brain. From Eagle, S, et al. (2009).

The Professional Medical Assistant. Philadelphia, PA: F.A. Davis Company: p. 540; with permission.

Nonkeratinized

Taste pore squamous epithelium

Light

taste cell

Dark

taste cell Nerve Basal cell

102 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

a region of the solitary nucleus, known as the

gustatory nucleus. The solitary nucleus also

receives sensory input from the gut, and interneurons connect the gut and taste areas, providing a functional link between visceral and taste

inputs. Information from the gustatory nucleus

is projected to the VPM nucleus of the thalamus, the same nucleus that receives touch and

proprioceptive input from the face by way of

the trigeminothalamic pathway discussed earlier.

From the VPM, taste information is projected

to the primary gustatory cortex on the insula

( Fig. 4-28 ), to a region of the frontal lobe called

the operculum, and to a multisensory region of

the orbitofrontal cortex. It is in the orbitofrontal

cortex where taste is integrated with input about

a food ’ s smell, appearance, and texture. Taste

information from the gustatory nucleus also

projects to, and receives input from, the hypothalamus and the amygdala. Cortical projections

are linked with our awareness of taste; projections to the hypothalamus and amygdala are

associated with the affective aspects of taste,

what we like and do not like, and our motivations around eating. Finally, there are projections to regions of the medulla that mediate

basic physiological functions and play a role in

swallowing, gag and vomit, the production of

saliva, digestion, and respiration. Taste, then, is

a multisensory process, involving integration at

many levels.

Smell and Smell Receptors

 Detection of smell involves the chemical processing of odorants, airborne chemical stimuli.

According to Bear and colleagues ( 2015 ), of the

thousands of smells that we can perceive, only

about 20% are actually pleasant, suggesting

that this system serves an important protective

FIGURE 4-28 Taste sensation is carried by the facial, glossopharyngeal, and vagus nerves to a region of the

solitary nucleus called the gustatory nucleus in the medulla. From here taste is projected to the ventral posterior

medial thalamic nucleus and from there to the primary gustatory cortex in the insula.

Primary gustatory

cortex (anterior

insula and frontal

operculum)

Lateral

ventricles

Third ventricle

Left ventral posterior

medial (VPM) nucleus

of the thalamus

Left gustatory nucleus

Pyramidal Medulla tract

Fourth ventricle

Solitario-thalamic tract

Amygdala

Anterior 2/3

of tongue

Lingual nerve

(from CN VII)

Posterior 1/3

of tongue

Glossopharyngeal

nerve (CN IX)

Epiglottis

Vagus nerve (CN X)

Nodose

ganglion

Petrosal

ganglion

Geniculate

ganglion

CHAPTER 4 Structure and Function of the Sensory Systems ■ 103

function, warning of dangers in the environment through detection of noxious odors. Smell

receptors are located in the olfactory epithelium, a layer of receptor cells lining the nose

( Fig. 4-29 ). This epithelium is coated by a thin

layer of mucus, and odorants dissolve in the

mucus and are concentrated there, enabling them

to interact with the receptor cells. Part of this

process involves the presence of receptor proteins in the mucus, which bind the odorants; our

ability to smell a variety of odors comes from

the existence of a large number of odorantreceptor proteins; humans have about 350. Interestingly, humans have relatively thin olfactory

epithelia and, as such, limited smell acuity when

compared with other animals. As was the case

for taste, our ability to detect the wide array of

environmental and personal odors comes from

activating several receptor cells, which themselves are more or less sensitive to specifi c odorants, and the resultant coding of information that

is sent to the CNS for interpretation. Olfactory

receptor cells are somewhat more sensitive to

some smells than others, but they do not show

specifi city for a single smell or group of smells.

This means that interpretation of smell stimuli

relies on CNS structures.

Smell Pathways

 Axons from receptor cells travel through a thin

bony structure called the cribriform plate,

FIGURE 4-29 Smell is detected by olfactory cells in the nasal epithelium. Fibers from these receptors enter the

olfactory bulb. From here, fi bers form the lateral olfactory tract carrying information to the piriform cortex.

Olfactory nerve

Piriform

cortex

Olfactory bulb

Glomerulus

Ethmoid bone

Nasal epithelium

Olfactory receptor cells

104 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

form the olfactory nerve (cranial nerve I), and

project to the olfactory bulb as individual fi bers

( Fig. 4-29 ). Because the fi bers do not coalesce

into a larger nerve, they tend to be very fragile

and easily injured or sheared by a blow to the

head. This helps explain the frequency of the

loss of smell in incidences of brain injury. In

the olfactory bulb, the organization of structures

provides a well-organized map of odor; further

odor discrimination requires additional central

processing. From the olfactory bulb, the lateral

olfactory tract carries smell input to the olfactory or piriform cortex ( Fig. 4-29 ). This makes

the olfactory system unique from other sensory

systems; it does not fi rst project to the thalamus,

instead going directly to a region of the cortex.

Fibers from the piriform cortex do project to the

thalamus and on to the prefrontal cortex. There is

specifi c mapping of odorant information within

the olfactory bulb, and the organization here is

thought to underlie our ability to interpret and

identify smell with input from the prefrontal

cortex. Additionally, fi bers from the lateral olfactory tract carry information to the amygdala and

the entorhinal cortex, and onto the prefrontal

cortex. The entorhinal pathway also projects to

the hippocampus. These limbic system projections are associated with the affective aspects

of smell as well as the close link behaviorally

between smell and emotion. The medial olfactory tract connects smell to other basal forebrain

structures; these connections mediate the autonomic responses to smell input.

Clinical Links to Taste or Smell

Sensitivity Differences

 Of interest related to the systems of taste and

smell and the integration and use of sensation,

is the potential link between eating and feeding

diffi culties and disorders and sensory modulation

concerns. Eating and feeding disorders represent a broad group of concerns, encompassing

children with and without additional diagnoses.

Here we will look briefl y at sensory concerns

related to food selectivity, non-organic failure to

thrive, eating concerns associated with ASD, and

sensory issues related to obesity.

 “Picky eating” is a concern that has no commonly accepted description but generally is

thought to encompass food refusal, food neophobia, limited variety in food choice, and,

often, other atypical eating behaviors ( Cano

et al., 2016 ; Kerzner et al., 2015 ). Picky eating

is not infrequently reported in young children

who are otherwise typical, and it is seen as

either not of immediate concern or on the mild

end of a continuum of eating disorders; many

children pass through a picky eating stage and

require no intervention. Multiple child factors,

parent factors, and child-parent interaction

factors appear to be at the core of picky eating

(for review, see Cano, Hoek, & Bryant-Waugh,

 2015 ). Factors related to both child and “feeder”

behaviors have been linked to sensory processing

differences in children with an array of feeding

problems ( Davis et al., 2013 ). Relative to child

factors, recent work indicated that food texture

contributes the most to picky eating ( Werthmann

et al., 2015 ). Additionally, picky eating in

some young children is related to tactile overresponsivity ( Nederkoorn, Jansen, & Havermans,

 2015 ; Smith, Roux, Naidoo, & Venter, 2005 ),

and food neophobia is linked with oral sensory

sensitivity ( Johnson, Davies, Boles, Gavin, &

Bellows, 2015 ). Interestingly, Nederkoorn and

colleagues identifi ed food texture and the anticipation of how the food will feel in our mouths

as a major issue, whereas Smith and colleagues

indicated foods were refused because of smell

and temperature. A relationship between feeding

problems and sensory modulation was also suggested by Boquin, Moskowitz, Donovan, and Lee

 ( 2014 ). Taking a broad view on the introduction

of new fruits and vegetables to young children,

not necessarily identifi ed as having either picky

eating or tactile defensiveness, Dazeley and

Houston-Price ( 2015 ) found that exploring the

sensory qualities of new foods outside of mealtime resulted in greater willingness to taste and

touch the foods. Such an approach, using playful

sensory-based opportunities, is consistent with a

core feature of SI.

 Although limited, there is some indication that children with non-organic failure to

thrive (NOFT) may have concomitant overresponsiveness to sensory input. Yi, Joung,

Choe, Kim, and Kwon ( 2015 ) found that overresponsiveness in tactile, vestibular, and oral

domains was more common in toddlers with

NOFT than in a control group. They also found

that these sensory concerns were related to

delays in development and to maladaptive mealtime behavior.

CHAPTER 4 Structure and Function of the Sensory Systems ■ 105

ASD and Sensory Modulation Concerns

 More signifi cant than picky eating, children with

ASD are frequently identifi ed as having eating

or feeding disorders. Although incidence is diffi cult to identify clearly, somewhat older studies

indicate that 46% to 90% of children with ASD

present with some form of eating disorder, often

persistent food refusal, restricted variety in

food, or food neophobia ( Ledford & Gast, 2006 ;

 Twachtman-Reilly, Amaral, & Zebrowski, 2008 ).

Although the underlying cause for these behaviors remains speculative, one suggested possibility is sensory sensitivities to characteristics of

food discussed earlier in this section: taste, smell,

texture, and temperature ( Cermak, Curtin, &

Bandini, 2010 ; Ledford & Gast, 2006 ; Marshall,

Hill, Ziviani, & Dodrill, 2014 ; Nadon, Feldman,

Dunn, & Gisel, 2011 ; Vissoker, Latzer, & Gal,

 2015 ; Zobel-Lachiusa, Andrianopoulos, Mailloux, & Cermak, 2015 ). In fact, Paterson and

Peck ( 2011 ) and Zobel-Lachiusa and colleagues

 ( 2015 ) identifi ed a strong correlation between

more problematic sensory behaviors and mealtime behavior concerns in children with ASD,

and the researchers suggested that intervention

directed toward ameliorating sensory sensitivities might improve quality of life for both the

child and family. Interestingly, in looking at

children with ASD and feeding disorders, and

children without ASD but with feeding disorders

considered “nonmedically complex,” Marshall

and colleagues found that both groups evidenced

oral motor and oral hypersensitivity, implicating

the sensory aspects of feeding disorders for a

broader population. Further, extreme taste-smell

sensitivity in children with ASD has been identifi ed as a sensory subtype by Lane and colleagues

( Lane, Dennis, & Geraghty, 2011 ; Lane, Molloy,

& Bishop, 2014 ; Lane, Young, Baker, & Angley,

 2010 ), and these investigators linked it to diffi -

culties in social communication; they did not

examine specifi c eating behaviors. It is important

to note that sensory sensitivities are not the only

consideration for children with ASD and feeding

or eating disorders; Vissoker and colleagues

 ( 2015 ) indicated that these problems are multifactorial and may be linked to well-documented

GI dysfunction in children with ASD.

Obesity and Sensory Modulation Concerns

 Other investigations of taste or smell sensitivity have focused on the issue of obesity. Rather

than the increased sensitivity reported for children with ASD, evidence indicates that taste

sensitivity is reduced in children with obesity,

particularly for salty, umami, and bitter tastes;

sweetness intensity was rated lower by children with obesity ( Overberg, Hummel, Krude,

& Wiegand, 2012 ). The causes of these differences are multifaceted, but they include learning

effects and exposure to new foods, as was the

case with picky eating. Children can be classifi ed as either “tasters” or “non-tasters,” and

research indicates that preschoolers categorized

as “non-tasters” showed a higher incidence of

obesity and a greater intake of high fat savory

foods; in contrast, “tasters” prefer sweets ( Keller

et al., 2014 ; Markam, Banda, Singh, Chakravarthy, & Gupta, 2015 ). There may be a role to be

played by occupational therapy in working with

children with obesity and reduced sensitivity or

poor sensory discrimination of taste, but this will

take time to tease out.

HERE ’ S THE EVIDENCE

Food neophobia is a term applied when individuals are fearful of trying new foods. Although

it is often considered a behavioral issue related

to feeding disorders, some investigators are

beginning to link it to sensory sensitivities. As

part of a larger and ongoing study of obesity,

Johnson, Davies, Boles, Gavin, and Bellows

 ( 2015 ) administered the Food Neophobia Scale

and the Sensory Profi le to a relatively large group

( n = 249) of preschool-aged children who were

otherwise typically developing. The researchers

also measured body mass index and food intake.

Findings suggested, among other things, a signifi cant relationship between oral sensory sensitivity and food neophobia, as well as among

food neophobia, limited vegetable consumption,

and limited dietary variety. Other considerations

to explain limited dietary variety and food neophobia included socioeconomic status (SES)

factors and ethnicity. The authors concluded

that more research is needed to better understand the overall relationships among sensoryrelated behaviors, food neophobia, limited

dietary variety, and other family and environmental variables.

Johnson, S. L., Davies, P. L., Boles, R. E., Gavin, W. J., & Bellows,

L. L. ( 2015 ). Young children ’ s food neophobia characteristics and

sensory behaviors are related to their food intake. Journal of

Nutrition, 145(11), 2610–2616.

106 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

HERE ’ S THE POINT

 • Olfaction and gustation are separate systems

neuroanatomically, but they are closely related

functionally.

 • Our ability to interpret the wide variety of

tastes and smells in the environment depends

on a complex coding and interpretation

process in these systems, which begins with

the receptors and continues through CNS

connections.

 • Eating and feeding disorders are an area of

functional overlap between taste and smell,

linked with over-responsivity; these disorders

also frequently are linked to disorders of tactile

modulation. A sensory integrative approach to

intervention may be warranted.

 • A large percentage of young children with

no specifi c diagnosis are noted to be “picky

eaters”; many of them will grow out of this

behavior with no intervention.

 • Children identifi ed with NOFT and ASD often

also show sensory sensitivities in conjunction

with feeding and eating challenges.

• There is growing evidence that children with

obesity may be classifi ed as “non-tasters,”

potentially under-responsive to taste, or with

poor taste discrimination.

 • Sensory-based feeding concerns may be

well served by occupational therapy to

address concerns related to sensory

over-responsivity.

Summary and Conclusions

 The major sensory systems subserving SI theory

are complex, and we have only scratched the

surface in explaining their structure and function.

Each system relies on receptors that respond to

one primary form of input and on the transformation of this input into an electrochemical form

that can be read by the CNS. Because all input

to the CNS eventually takes the form of electrochemical signals, interpretation of specifi c input

depends on the receptors, the specifi c pathways

over which the information is sent, and characteristics of the input, including frequency and

intensity of transmission. Across all systems,

the processing of sensory input begins subcortically, and a great deal of processing takes place

in the brainstem, regions of the midbrain, and

the thalamus. Our ability to modulate sensation

is subcortical; more detail on sensory modulation can be found in Chapter 6 (Sensory Modulation Functions and Disorders). Perception

and discrimination, however, require the cortex.

You will fi nd more on sensory discrimination

in Chapter 7 (Sensory Discrimination Functions

and Disorders).

 Integration of inputs takes place in a multitude of CNS locations and subserves a multitude

of functions. Although we have looked at each

system individually, many comments have been

made throughout this chapter related to multisensory integration; none of these systems functions “in a vacuum.” Touch and proprioception

provide information necessary for the establishment of body scheme; proprioception, vision,

and vestibular inputs are crucial for our ability to

maintain upright posture and move our body in

and through space. Touch and vision interact in

the process of developing skills such as stereognosis, determining “what” an object is; sound

and vision contribute to our ability to determine

“where” people and things are in the environment. In this chapter, we focused on the use of

sensation in allowing us to perceive the environment but alluded to the application of SI in the

production of movement. This will be detailed in

 Chapter 5 (Praxis and Dyspraxia).

 The complexity within and between sensory

systems is diffi cult to capture in one short

chapter; you have likely found it diffi cult to

digest, especially if you are new to the neuroscience foundations for SI theory. In Table 4-3

and the appendix that follows, we provide key

points regarding the structure, function, and

interaction among these systems that you may

fi nd useful!

CHAPTER 4 Structure and Function of the Sensory Systems ■ 107

TABLE 4-3 Sensory Systems and Projections

PATHWAY ORGANIZATION FUNCTION

FIBERS

CROSS . . . FIRST SYNAPSE SECOND SYNAPSE

THIRD-ORDER

SYNAPSE

And

Beyond

. . .

DCML Precise somatotopic

organization throughout

Little convergence

Few relays

Transmit size, form, texture

information

Detect movement of touch

on skin

Convey spatial and

temporal aspects of touch

Gracile

and

cuneate

nuclei of

medulla

Gracile and cuneate

nuclei

VPL of thalamus

Reticular formation

Primary and

secondary somatic

cortex

Areas 5 and 7 of

parietal lobe

Anterolateral Somatotopic, but less

specifi c

More convergence

Pain, crude touch,

temperature, tickle, neutral

warmth

Dorsal

horn of

the spinal

cord

Dorsal horn of the

spinal cord

VPL of the

thalamus

Reticular formation

 Periaqueductal

gray

 Tectum

 Hypothalamus

Primary and

secondary

somatosensory

cortex

Other thalamic

nuclei

Trigeminothalamic Somatotopic Discriminative touch from

face and mouth

Pain, temperature,

nondiscriminative touch

After

synapsing

in the

pons and

brainstem

Principal sensory

nucleus of the

trigeminal nerve

Spinal nucleus of

the trigeminal nerve

Ventral posterior

medial nucleus of

the thalamus

Primary

somatosensory

cortex

Continued

108 ■ PART II The Neuroscience Basis of Sensory Integration Disorders PATHWAY ORGANIZATION FUNCTION FIBERS CROSS . . . FIRST SYNAPSE SECOND SYNAPSE THIRD-ORDER SYNAPSE And Beyond . . . Vestibular Position and movement of the head in space Maintenance of balance Coordination of the eyes Fixation of the eyes as the body moves through space Detection of speed and direction of movement After synapsing in the vestibular nuclei in the medulla and pons Vestibular ganglion Cerebellum Oculomotor nuclei Alpha and gamma motor neurons VPL of the thalamus Areas 3 and 2v of the cortex Auditory Tonotypic Amplitude tuning curve Sound detection and localization Spiral ganglion in ear Ventral and dorsal cochlear nuclei Superior olive Trapezoid body Inferior colliculus Medial geniculate nucleus of thalamus Auditory cortex Precentral gyrus Visual Cones: little convergence,

high degree of spatial

resolution

Rods: signifi cant

convergence; high light

sensitivity; low resolution

Detailed organization

of information carried

throughout this system

Cones: day vision, color

Rods: night vision

At optic

chiasm

Bipolar cells in

retina

Ganglion cells in

retina

Superior colliculus

Lateral geniculate

nucleus of

thalamus

Primary

visual

cortex

TABLE 4-3 Sensory Systems and Projections—cont’d

CHAPTER 4 Structure and Function of the Sensory Systems ■ 109

Where Can I Find More?

 In developing the material in this chapter, many

sources were tapped because no single neuroscience text does it all. Some emphasize function, some emphasize structure, others take a

systems approach, and still others take a geographic approach. All have their place, and all

answer somewhat different questions. Rather

than reference each statement that appeared in

the chapter, we credit several sources now as they

provided essential background, detail, and guidance to the structural and functional material in

this chapter.

 Bear, M. F., Connors, B. W., & Paradiso, M. A.

(2015). Neuroscience: Exploring the brain

 (4th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.

 Haines, D. E. (2013). Fundamental neuroscience

for basic and clinical applications. New York,

NY: Churchill Livingstone.

 Jessell, T. M., Kandel, E. R., & Schwartz, J. H.

(2012). Principles of neural science (5th ed.).

New York, NY: McGraw-Hill.

 Kandel, E. R., Schwartz, J. H., Jessell, T. M.,

Siegelbaum, S. A., & Hudspeth, A. J. (2013).

Principles of neural science (5th ed.). New

York, NY: McGraw-Hill Companies, Inc.

 Kiernan, J., & Rajakumar, R. (2014). Barr ’ s the

human nervous system: An anatomical viewpoint. Philadelphia, PA: Lippincott Williams

& Wilkins.

 Purves, D., Augustine, G. J., Fitzpatrick, D.,

Hall, W. C., LaMantia, A.-S., & White, L. E.

(2011). Neuroscience (5th ed.). Sunderland,

MA: Sinauer Associates, Inc.

 Siegel, A., & Sapru, H. N. (2013). Essential neuroscience (3rd ed.). Philadelphia, PA: Lippincott Williams & Wilkins.

 Squire, L., Berg, D., Bloom, F. E., duLac, S.,

Ghosh, A., & Spitzer, N. C. (2012). Fundamental neuroscience (4th ed.). Cambridge,

MA: Academic Press.

 At appropriate points within this chapter, we

referenced sources that offer more limited input

and particularly good explanations of specifi c

constructs.

 References

 Abraira , V. E. , & Ginty , D. D. ( 2013 ). The sensory

neurons of touch . Neuron, 79, 618 – 639 .

 Ayres , A. J. ( 1972 ). Sensory integration and

learning disorders. Los Angeles, CA : Western

Psychological Services.

 Baloh , R. , & Kerber , K. ( 2010 ). Clinical

neurophysiology of the vestibular system. New

York, NY : Oxford University Press .

 Bear , M. F. , Connors , B. W. , & Paradiso , M. A.

( 2015 ). Neuroscience: Exploring the brain

 ( 4th ed .). Philadelphia, PA : Lippincott Williams &

Wilkins .

 Blackwell , P. L. ( 2000 ). The infl uence of touch on

child development: Implications for intervention.

Infants and Young Children, 13 ( 1 ), 25 – 39 .

 Boquin , M. M. , Moskowitz , H. R. , Donovan , S. M. , &

 Lee , S. Y. ( 2014 ). Defi ning perceptions of picky

eating obtained through focus groups and conjoint

analysis. Journal of Sensory Studies, 29 ( 2 ),

126 – 138 . doi:10.1111/joss.12088

 Cano , S. C. , Hoek , H. W. , & Bryant-Waugh , R.

( 2015 ). Picky eating: The current state of research .

Current Opinion in Psychiatry, 28, 448 – 454 .

 Cano , S. C. , Hoek , H. W. , van Hoeken , D. , de Barse ,

 L. M. , Jaddoe , V. W. V. , Verhulst , F. C. , &

 Tiemeier , H. ( 2016 ). Behavioral outcomes of

picky eating in childhood: A prospective study

in the general population. Journal of Child

Psychology and Psychiatry, 57 ( 11 ),

1239 – 1246 .

 Cermak , S. A. , Curtin , C. , & Bandini , L. G. ( 2010 ).

 Food selectivity and sensory sensitivity in children

with autism spectrum disorders. Journal of the

American Dietetic Association, 110, 238 – 246 .

 doi:10.1016/j.jada.2009.10.032

 Chen , H.-Y. , Yang , H. , Chi , H. J. , & Chen , H. M.

( 2013 ). Physiological effects of deep touch

pressure on anxiety alleviation: The weighted

blanket approach. Journal of Medical and

Biological Engineering, 33 ( 5 ), 463 – 470 .

 Cohen , H. ( 1999 ). Neuroscience for Rehabilitation

( 2nd ed. ). Philadelphia, PA : Lippincott

Williams & Wilkins .

 Collier , C. ( 1985 ). Emotional expression. Hillsdale,

NJ : Lawrence Erlbaum Associates .

 Coq , J. O. , & Xerri , C. ( 1999 ). Tactile

impoverishment and sensorimotor restriction

deteriorate the forepaw cutaneous map in the

primary somatosensory cortex of adult rats .

Experimental Brain Research, 129 ( 4 ),

518 – 531 .

 Craig , A. D. ( 2002 ). How do you feel? Interoception:

The sense of the physiological condition of

the body . Nature Reviews: Neuroscience, 3 ( 8 ),

 655 – 666 .

 Craig , A. D. ( 2009 ). How do you feel now? The

anterior insula and human awareness. Nature

Reviews: Neuroscience, 10 ( 1 ), 59 – 70 .

 Craig , A. D. ( 2015 ). How do you feel? An

interoceptive moment with your neurobiological

self. Princeton, NJ : Princeton University Press .

 Crapse , T. B. , & Sommer , M. A. ( 2008 ). Corollary

discharge circuits in the primate brain . Current

Opinion in Neurobiology, 18, 552 – 557 .

110 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 Croker , C. A. ( 2013 ). Motor learning and control for

practitioners. Scottsdale, AZ : Holcomb Hathaway

Publishers, Inc .

 Davis , A. M. , Bruce , A. S. , Khasawneh , R. , Schulz , T. ,

 Fox , C. , & Dunn , W. ( 2013 ). Sensory processing

issues in young children presenting to an

outpatient feeding clinic: A retrospective chart

review . Journal of Pediatric Gastroenterology

and Nutrition, 56 ( 2 ), 156 – 160 . doi:10.1097/

MPG.0b013e3182736e19

 Dazeley , P. , & Houston-Price , C. ( 2015 ). Exposure

to foods’ non-taste sensory properties. A nursery

intervention to increase children ’ s willingness to

try fruit and vegetables. Appetite, 84, 1 – 6 .

 Di Martino , A. , Ross , K. , Uddin , L. Q. , Sklar ,

A. B. , Castellanos , F. X. , & Milham , M. P.

( 2009 ). Functional brain correlates of social and

nonsocial processes in autism spectrum disorders:

An activation likelihood estimation meta-analysis.

Biologic Psychiatry, 65 ( 1 ), 63 – 74 .

 Diamond , M. C. , & Hopson , J. ( 1998 ). Magic trees of

the mind. New York, NY : Dutton .

 Dieterich , M. , & Brandt , T. ( 2015 ). The bilateral

central vestibular system: Its pathways, functions,

and disorders. Annals of the New York Academy of

Sciences, 1343, 10 – 26 . doi:10.1111/nyas.12585

 Edelson , S. M. , Edelson , M. G. , Kerr , D. C. R. , &

 Grandin , T. ( 1999 ). Behavioral and physiological

effects of deep pressure on children with autism:

A pilot study evaluating the effi cacy of Grandin ’ s

hug machine. American Journal of Occupational

Therapy, 53 ( 2 ), 145 – 152 .

 Elwin , M. , Schröder , A. , Ek , L. , & Kjellin , L.

( 2012 ). Autobiographical accounts of sensing in

Asperger syndrome and high-functioning autism.

Archives of Psychiatric Nursing, 26 ( 5 ), 420 – 429 .

 doi:10.1016/j.apnu.2011.10.003

 Ferrell , W. R. , & Smith , A. ( 1988 ). Position sense at

the proximal interphalangeal joint of the human

index fi nger . Journal of Physiology, 399, 49 – 61 .

 Fiene , L. , & Brownlow , C. ( 2015 ). Investigating

interoception and body awareness in adults with

and without autism spectrum disorder . Autism

Research, Online 25 March 2015. doi:10.1002/

aur.1486

 Fisher , A. G. ( 1989 ). Objective assessment of the

quality of response during two equilibrium tests .

Physical and Occupational Therapy in Pediatrics,

9 ( 3 ), 57 – 78 .

 Fisher , A. G. , & Bundy , A. C. ( 1989 ). Vestibular

stimulation in the treatment of postural and related

disorders. In O. D. Payton , R. P. DiFabio , S. V.

 Paris , E. J. Prostas , & A. F. VanSant ( Eds .), Manual

of physical therapy techniques ( pp . 239 – 258 ).

 New York, NY : Churchill Livingstone .

 Fisher , A. G. , Mixon , J. , & Herman , R. ( 1986 ). The

validity of the clinical diagnosis of vestibular

dysfunction. Occupational Therapy Journal of

Research, 6, 3 – 20 .

 Gilman , S. , & Newman , S. W. ( 1992 ). Essentials of

clinical neuroanatomy and neurophysiology

( 9th ed .). Philadelphia, PA : F.A. Davis .

 Gokeler , A. , Benjaminse , A. , Hewett , T. E. , Lephart ,

 S. M. , Engebretsen , L. , Ageberg , E. , . . .

Dijkstra, P. U. ( 2011 ). Proprioceptive defi cits

after ACL injury: Are they clinically relevant?

British Journal of Sports Medicine, 46,

180 – 192 .

 Goldberg , G. ( 1985 ). Supplementary motor area

structure and function: Review and hypotheses.

Behavioral and Brain Sciences, 8, 567 – 616 .

 Goldberg , J. M. , Wilson , V. J. , Cullen , K. E. ,

 Angelakik , D. E. , Broussard , D. M. , ButtnerEnnever , J. A. , . . . Minor , L. B. ( 2012 ). The

vestibular system. A 6th sense . New York, NY :

 Oxford University Press, Inc .

 Goodwin , A. W. , & Wheat , H. E. ( 2004 ). Sensory

signals in neural populations underlying tactile

perception and manipulation. Annual Review of

Neuroscience, 27, 53 – 77 . doi:10.1146/annurev.

neuro.26.041002.131032

 Haines , D. E. ( 2013 ). Fundamental neuroscience for

basic and clinical applications. New York, NY :

 Churchill Livingstone .

 Haron , M. , & Henderson , A. ( 1985 ). Active and

passive touch in developmentally dyspraxic and

normal boys . Occupational Therapy Journal of

Research, 5, 102 – 112 .

 Holt , J. C. , Lysakowski , A. , & Goldberg , J. M.

( 2011 ). The efferent vestibular system . In

D. K. Ryugo , R. R. Fay , & A. N. Popper ( Eds .),

Auditory and vestibular efferents ( pp . 135 – 186 ).

 New York, NY : Springer .

 Hubel , D. H. , & Weisel , T. N. ( 1965 ). Binocular

interaction in striate cortex of kittens reared with

artifi cial squint . Journal of Neurophysiology, 28,

 1041 – 1059 .

 Hubel , D. H. , Weisel , T. N. , & LeVay , S. ( 1977 ).

 Plasticity of ocular dominance columns in monkey

striate cortex. Philosophical Transactions of the

Royal Society of London, Series B. Biological

Science, 278, 377 – 409 .

 Jenkins , W. M. , Merzenich , M. M. , Ochs , M. T. ,

 Allard , T. , & Guic-Robles , E. ( 1990 ). Functional

reorganization of primary somatosensory cortex in

adult owl monkeys after behaviorally controlled

tactile stimulation. Journal of Neurophysiology,

63, 82 – 104 .

 Johansson , R. S. , & Flanagan , J. R. ( 2009 ). Coding

and use of tactile signals from the fi ngertips

in object manipulation tasks . Nature Reviews.

Neuroscience, 10 ( 5 ), 345 – 359 . doi:10.1038/

nrn2621

 Johnson , S. L. , Davies , P. L. , Boles , R. E. , Gavin ,

W. J. , & Bellows , L. L. ( 2015 ). Young children ’ s

food neophobia characteristics and sensory

behaviors are related to their food intake. Journal

of Nutrition, 145 ( 11 ), 2610 – 2616 .

 Jones , L. A. , & Smith , A. M. ( 2014 ). Tactile sensory

system: Encoding from the periphery to the

cortex. Wiley Interdisciplinary Review Systems

Biology and Medicine, 6 ( 3 ), 279 – 287 .

 Kandel , E. R. , Schwartz , J. H. , Jessell , T. M. ,

 Siegelbaum , S. A. , & Hudspeth , A. J. ( 2013 ).

CHAPTER 4 Structure and Function of the Sensory Systems ■ 111

Principles of neural science ( 5th ed .). New York,

NY : McGraw-Hill Companies, Inc .

 Keller , K. L. , Olsen , A. , Cravener , T. L. , Bloom ,

 R. , Chung , W. K. , Deng , L. , . . . Meyermann , K.

( 2014 ). Bitter taste phenotype and body weight

predict children ’ s selection of sweet and savory

foods at a palatable-test meal . Appetite, 77C,

 113 – 121 .

 Kerzner , B. , Milano , K. , MacLean , W. C. , Berall ,

 G. , Stuart , S. , & Chatoor , I. ( 2015 ). A practical

approach to classifying and managing feeding

diffi culties . Pediatrics, 135 ( 2 ), 344 – 353 .

 doi:10.1542/peds.2014-1630

 Kirsch , V. , Keeser , D. , Hergenroeder , T. , Erat , O. ,

 Ertl-Wagner , B. , Brandt , T. , & Dieterich , M.

( 2014 ). Structural and functional connectivity

mapping of the vestibular circuitry from human

brainstem to cortex. Brain Structure and Function,

221 ( 3 ), 1291 – 1308 .

 Lane , A. E. , Dennis , S. J. , & Geraghty , M. E. ( 2011 ).

 Brief report: Further evidence of sensory subtypes

in autism. Journal of Autism and Developmental

Disorders, 41 ( 6 ), 826 – 831 . doi:10.1007/

s10803-010-1103-y

 Lane , A. E. , Molloy , C. A. , & Bishop , S. L. ( 2014 ).

 Classifi cation of children with autism spectrum

disorder by sensory subtype: A case for sensorybased phenotypes. Autism Research, 7 ( 3 ),

 322 – 333 . doi:10.1002/aur.1368

 Lane , A. E. , Young , R. L. , Baker , A. E. Z. , & Angley ,

 M. T. ( 2010 ). Sensory processing subtypes in

autism: Association with adaptive behavior .

Journal of Autism and Developmental Disorders,

40 ( 1 ), 112 – 122 . doi:10.1007/s10803-009-0840-2

 Ledford , J. R. , & Gast , D. L. ( 2006 ). Feeding

problems in children with autism spectrum

disorders: A review . Focus on Autism and Other

Developmental Disabilities, 21 ( 3 ), 153 – 166 .

 Liem , F. , Hurschler , M. A. , Jancke , L. , & Meyer , M.

( 2014 ). On the planum temporale lateralization

in suprasegmental speech perception: Evidence

from a study investigating behavior, structure,

and function. Human Brain Mapping, 35,

 1779 – 1789 .

 Liu , C.-S.J. , Bryan , R. N. , Miki , A. , Woo , J. H. , Liu ,

 G. T. , & Elliot , M. A. ( 2006 ). Magnocellular and

parvocellular visual pathways have different blood

oxygen level–dependent signal time courses in

human primary visual cortex. American Journal of

Neuroradiology, 27, 1628 – 1634 .

 Markam , V. , Banda , N. R. , Singh , G. , Chakravarthy ,

 K. , & Gupta , M. ( 2015 ). Does taste perception

effect body mass index in preschool children?

Journal of Clinical and Diagnostic Research,

9 ( 12 ), ZC01 – ZC04 .

 Marshall , J. , Hill , R. J. , Ziviani , J. , & Dodrill , P.

( 2014 ). Features of feeding diffi culty in children

with autism spectrum disorder . International

Journal of Speech and Language Pathology, 16,

 51 – 58 .

 Matthews , P. B. C. ( 1988 ). Proprioceptors and their

contribution to somatosensory mapping: Complex

messages require complex processing. Canadian

Journal of Physiology and Pharmacology, 66,

 430 – 438 .

 McCloskey , D. I. ( 1985 ). Knowledge about

muscular contractions. In E. V. Evarts , S. P.

 Wise , & B. Bousfi eld ( Eds .), The motor system

in neurobiology ( pp . 149 – 153 ). New York, NY :

 Elsevier .

 McCloskey , D. I. , Cross , M. J. , Honner , R. , & Potter ,

 E. K. ( 1983 ). Sensory effects of pulling and

vibrating exposed tendons in man . Brain, 106,

 21 – 37 .

 McHaffi e , J. G. , Fuentes-Santamaria , J. C. , Alvarado ,

 A. L. F. F. , Gutierrez-Ospina , G. , & Stein , B. E.

( 2012 ). Anatomical features of the intrinsic

circuitry underlying multisensory integration

in the superior colliculus. In B. E. Stein ( Ed .),

The new handbook of multisensory processes

( pp . 31 – 48 ). Cambridge, MA : The MIT Press .

 Moberg , E. ( 1983 ). The role of cutaneous afferents in

position sense, kinaesthesia, and motor function of

the hand . Brain, 106, 1 – 19 .

 Mogliner , A. , Grossmann , J. A. , Ribary , U. , Joliot ,

 M. , Volkmann , J. , Rapaport , D. , . . . Llinas , R. R.

( 1993 ). Somatosensory cortical plasticity in adult

humans revealed by magnetoencephalography .

Proceedings of the National Academy of Sciences,

USA, 90, 3593 – 3597 .

 Montagu , A. ( 1978 ). Touching: The human

signifi cance of the skin. New York, NY : Harper

and Row .

 Nadon , G. , Feldman , D. E. , Dunn , W. , & Gisel , E.

( 2011 ). Association of sensory processing and

eating problems in children with autism spectrum

disorders. Autism Research and Treatment, Article

ID 541926, 8 pages .

 Nashner , L. M. ( 1982 ). Adaptation of human

movement to altered environments. Trends in

Neuroscience, 5, 351 – 361 .

 Nederkoorn , C. , Jansen , A. , & Havermans , R. C.

( 2015 ). Feel your food. The infl uence of

tactile sensitivity on picky eating in children.

Appetite, 84, 7 – 10 . doi:10.1016/j.appet.2014

.09.014

 Overberg , J. , Hummel , T. , Krude , H. , & Wiegand , S.

( 2012 ). Differences in taste sensitivity between

obese and non-obese children and adolescents.

Archives of Diseases of Childhood, 97,

 1048 – 1052 .

 Paterson , H. , & Peck , K. ( 2011 ). Sensory processing

ability and eating behaviour in children with

autism . Journal of Human Nutrition and Dietetics,

24, 301 .

 Proske , U. , & Gandevia , S. C. ( 2012 ). The

proprioceptive senses: Their roles in signaling

body shape, body position and movement, and

muscle force. Physiologic Review, 92, 1651 – 1697 .

 doi:10.1152/physrev.00048.2011

 Purves , D. , Augustine , G. J. , Fitzpatrick , D. , Hall ,

 W. C. , LaMantia , A.-S. , & White , L. E. ( 2011 ).

Neuroscience ( 5th ed .). Cambridge, MA : Sinauer

Associates, Inc .

112 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 Recanzone , G. H. , Merzenich , M. M. , & Jenkins ,

 W. M. ( 1992 ). Frequency discrimination-training

engaging a restricted skin surface results in

an emergence of a cutaneous response zone in

cortical area 3a . Journal of Neurophysiology,

67 ( 5 ), 1057 – 1070 .

 Reynolds , S. , Lane , S. J. , & Mullen , B. ( 2015 ).

 Effects of deep pressure stimulation on

physiological arousal. American Journal of

Occupational Therapy, 69 ( 3 ), 6903350010p1 -

 6903350010p5 . doi:10.5014/ajot.2015.015560

 Rine , R. M. , & Wiener-Vacher , S. ( 2013 ). Evaluation

and treatment of vestibular dysfunction in

children. NeuroRehabilitation, 32 ( 3 ),

 507 – 518 .

 Robb , R. M. , Mayer , D. L. , & Moore , B. D. ( 1987 ).

 Results of early treatment of unilateral congenital

cataracts. Journal of Pediatric Ophthalmology and

Strabismus, 24, 178 – 181 .

 Roberts , T. D. M. ( 1978 ). Neurophysiology of

postural mechanisms ( 2nd ed .). Boston, MA :

 Butterworths .

 Rose , M. F. , Ahmad , K. A. , Thaller , C. , &

 Zoghbi , H. Y. ( 2009 ). Excitatory neurons of

the proprioceptive, interoceptive, and arousal

hindbrain networks share a developmental

requirement for math . Proceedings of the National

Academy of Science, 106 ( 52 ), 22462 – 22467 .

 Sahley , T. L. , & Musiek , F. E. ( 2015 ). Basic

fundamentals in hearing science. San Diego, CA :

 Plural Publishing .

 Schmidt , R. , & Lee , T. ( 2011 ). Motor control and

learning. A behavioral emphasis ( 5th ed .).

 Champaign, IL : Human Kinetics .

 Sherrington , C. S. ( 1906 ). The integrative action

of the nervous system. New Haven, CT : Yale

University Press.

 Siegel , A. , & Sapru , H. N. ( 2013 ). Essential

neuroscience ( 3rd ed .). Philadelphia, PA :

 Lippincott Williams & Wilkins .

 Siegel , A. , Sapru , H. N. , & Siegel , H. ( 2015 ).

Essential Neuroscience ( 3rd ed. ). Baltimore, MD :

 Lippincott Williams & Wilkins .

 Smith , A. M. , Roux , S. , Naidoo , N. T. R. , & Venter ,

 D. J. L. ( 2005 ). Food choices of tactile defensive

children. Nutrition, 21, 14 – 19 .

 Soto , E. , & Vega , R. ( 2010 ). Neuropharmacology

of vestibular system disorders. Current

Neuropharmacology, 8 ( 1 ), 26 – 40 .

 Squire , L. , Berg , D. , Bloom , F. E. , du Lac , S. ,

 Ghosh , A. , & Spitzer , N. C. ( 2012 ). Fundamental

neuroscience ( 4th ed .). Philadelphia, PA :

 Academic Press .

 Tracey , D. J. ( 1985 ). Joint receptors and the

control movement. In E. V. Evarts , S. P. Wise ,

& B. Bousfi eld ( Eds .), The motor system in

neurobiology ( pp . 178 – 182 ). New York, NY :

 Elsevier .

 Twachtman-Reilly , J. , Amaral , S. C. , & Zebrowski ,

P. P. ( 2008 ). Addressing feeding disorders in

children on the autism spectrum in school-based

settings: Physiological and behavioral issues.

Language, Speech, and Hearing Services in

Schools, 39, 261 – 272 .

 Uddin , L. Q. , & Menon , V. ( 2009 ). The anterior

insula in autism: Under-connected and underexamined. Neuroscience and Biobehavioral

Reviews, 33, 1198 – 1203 .

 Vasa , R. A. , Carroll , L. M. , Nozzolillo , A. A. ,

 Mahajan , R. , Mazurek , M. O. , Bennett , A. E. ,

. . . Bernal , M. P. ( 2014 ). A systematic review

of treatments for anxiety in youth with autism

spectrum disorders. Journal of Autism and

Developmental Disorders, 44, 3215 – 3229 .

 Vissoker , R. E. , Latzer , Y. , & Gal , E. ( 2015 ). Eating

and feeding problems and gastrointestinal

dysfunction in autism spectrum disorders.

Research in Autism Spectrum Disorders, 12,

 10 – 21 .

 Werthmann , J. , Jansen , A. , Havemans , R. ,

 Niederkoom , C. , Kremers , S. , & Roefs , A. ( 2015 ).

 Bits and pieces. Food texture infl uences food

acceptance in young children. Appetite, 84, 81 – 87 .

 doi:10.1016/j.appet.2014.09.025

 Wilson , V. J. , & Melvill Jones , G. ( 1979 ).

Mammalian vestibular physiology. New York, NY :

 Plenum .

 Yi , S.-H. , Joung , Y.-S. , Choe , Y. H. , Kim , E.-H. , &

 Kwon , J.-Y. ( 2015 ). Sensory processing diffi culties

in toddlers with nonorganic failure-to-thrive

and feeding problems. Journal of Pediatric

Gastroenterology and Nutrition, 60 ( 6 ), 819 – 824 .

 Yu , T.-Y. , Hinojosa , J. , Howe , T.-H. , & Voelbel ,

 G. T. ( 2012 ). Contribution of tactile and

kinesthetic perceptions to handwriting in

Taiwanese children in fi rst and second grade .

OTJR: Occupation, Participation, and Health,

32 ( 3 ), 87 – 94 .

 Zigmond , M. J. , Bloom , F. E. , Landic , S. C. , Roberts ,

 J. L. , & Squire , L. R. ( 1999 ). Fundamental

neuroscience. Boston, MA : Academic Press .

 Zobel-Lachiusa , J. , Andrianopoulos , M. V. , Mailloux ,

 Z. , & Cermak , S. A. ( 2015 ). Sensory differences

and mealtime behavior in children with autism.

American Journal of Occupational Therapy,

69 ( 2 ), 97 – 105 . doi:10.5014/ajot.2015.016790

113

 APPENDIX 4-1

System Highlights

Somatosensory System

 • Receptors are in the skin and around

the joints, making this system very

pervasive.

 • Interpretation of input depends on the

combination of receptors activated, receptor

density, and receptor fi eld size.

 • Two major subdivisions carry information

from the body to the CNS: the DCML and

the AL systems.

 • DCML:

• Tactile discrimination, vibration, touchpressure, proprioception, temporal and

spatial aspects of a stimulus

• Main projections: thalamus, S-I, S-II,

areas 5, 7

 • Proprioception:

 • Information travels within the DCML

 • Perception of joint and body movement,

and position of body and body segments

in space

 • Main sources: muscle spindles, skin

mechanoreceptors, centrally generated

motor commands

 • Proprioceptive and vestibular inputs

are closely connected functionally,

contributing to development of body

scheme and postural responses,

postural tone and equilibrium, and

stabilization of head and eyes during

movement

 • AL:

 • Pain, temperature, light touch, tickle

 • Includes the following pathways:

spinothalamic, spinoreticular,

spinomesencephalic, spinohypothalamic

 • Main projections: thalamus, S-I, S-II;

reticular formation, periaqueductal gray

and midbrain tectum; hypothalamus (as

suggested by pathway names)

 • Trigeminothalamic pathway:

 • Carries all forms of somatosensory

information from the face to the CNS

 • Main projections: thalamus, S-I

 • Somatosensation has a pervasive infl uence

on occupational performance because of the

wide distribution of receptors and widespread

projections within the CNS.

 • There is considerable overlap among

projections of two major subdivisions with

many potential points of interaction.

Vestibular System

 • Receptors are hair cells in two structures

within inner ear:

 • Otolith organs: respond to linear

movement and gravity, head tilt in any

direction

 • Semicircular canals: respond to angular

movement of the head; respond best to

transient, quick movements

 • Activity of receptors provides tonic input to

the CNS about the movement and position of

the head in space.

 • Vestibular nerve fi bers project to vestibular

nuclei in the brainstem and from there to:

 • Cerebellum: reciprocal connections

for ongoing control of eye and head

movements and posture

 • Oculomotor nuclei: serving to fi x the eyes

as the head and body move

• Source of vestibular-ocular refl ex and

nystagmus

 • Spinal cord: infl uences on muscle tone

and ongoing postural adjustments

 • Thalamus and cortex: integration with

somatosensory inputs; play a role

in perception of motion and spatial

orientation

114 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

Auditory System

 • Hair cell receptors function similar to those

in the vestibular system.

 • Sound energy must be changed to vibration

and to fl uid movement energy to activate

receptors.

 • Two major auditory pathways:

 • Core pathway

• Fastest and most direct

• Maintains precise organization

throughout course

• Transmits sound frequency

 • Belt pathway

• Less well organized

• Surrounds core pathway

• Transmits information relative to

timing and intensity of sound input

• Important in bilateral interaction of

sound

 • Main auditory projections of both core and

belt pathways from cochlear nuclei:

 • Most direct route: axons from the lateral

lemniscus project to inferior colliculus

 • Ipsilateral and contralateral projections to

the superior olivary complex and onto the

inferior colliculus

 • Fibers forming the trapezoid body project

to the superior olivary complex

 • From the inferior colliculus, most fi bers

project to the medial geniculate nucleus

(MGN) of the thalamus and from there to

the auditory cortex, areas 41 and 42, and

auditory association cortex, area 22.

 • Other MGN projections go to the limbic

system and temporal and parietal lobes; these

are thought to play a role in arousal and

attention.

 • Auditory inputs are integrated with

somatosensory inputs in the SC to play a role

in controlling orientation of the head, eyes,

and body to sound.

Visual System

 • Receptors are rods and cones, responding to

night and day vision, respectively.

 • Rods are slow-responding receptors,

with the capacity to sum input even in

dim light.

 • Cones rapidly respond to changes in light

and provide color vision.

 • The retina is a complex multilayer structure,

and a great deal of processing goes on

here before information is transmitted

to the CNS.

 • Three pathways to the CNS:

 • Lateral geniculate pathway

• Has parvocellular (P) and

magnocellular (M) divisions

processing information related to

the what and where of an object,

respectively

• Projects to the visual cortex (areas

17 and 19) and on to the inferior and

superior temporal cortex for additional

processing and recognition of faces,

shapes, and motion

 • SC pathway

• Responses to horizontal movement in

visual fi eld

• Integration with somatosensory input

from thalamus

• Projects to thalamus, spinal cord,

and oculomotor nuclei to play a role

in coordination of posture and eye

movements

 • Accessory optic tract pathway

• Optic tract projections to accessory

nuclei around the oculomotor nucleus,

medial vestibular nucleus, and

thalamus

• Projects to inferior olive and on to

cerebellum

• Plays a role in oculomotor adaptation

115

CHAPTER

5

Praxis and Dyspraxia

 Sharon A. Cermak , EdD, OTR/L, FAOTA ■ Teresa A. May-Benson , ScD, OTR/L, FAOTA

 Chapter 5

Upon completion of this chapter, the reader will be able to:

✔ Describe terminology and explain diagnoses

related to disorders of praxis.

✔ Describe the role of sensation and sensory

integration (SI) theory in understanding praxis

and dyspraxia.

✔ Discuss and compare diffi culties associated

with ideation, somatodyspraxia, and bilateral

integration and sequencing.

✔ Describe neuroanatomic mechanisms

hypothesized to underlie praxis.

✔ Explain the impact of disorders of praxis on

development and occupational performance

and daily functioning.

✔ Become familiar with evidence-based literature

related to sensory-based disorders of praxis.

 Etiology of developmental dyspraxia clearly is not understood, perhaps because

there is little agreement as to what it is and how it can be assessed.

 — Sugden & Keogh ( 1990 , p. 133)

LEARNING OUTCOMES

Introduction

 Ayres ( 1985 ) defi ned praxis as “the neurological

process by which cognition directs motor action;

motor or action planning is that intermediary

process that bridges ideation and motor execution to enable adaptive interactions with the

physical world” (p. 71). Thus, praxis pertains to

more than just physical acts of interacting with

the environment, it encompasses the process of

conceptualizing and planning those motor acts.

It is a process that requires knowledge of actions

and of objects, motivation, and intention on the

part of the person.

 Researchers’ interest in praxis arose from

investigations with adults who had sustained

traumatic brain injury, primarily to the left

frontal or parietal lobes, resulting in the inability to perform voluntary or goal-directed actions

( Foundas, 2013 ). This disorder, known as

apraxia, interfered with the ability to perform

learned actions and impeded the ability to use

gestures for communication in the absence of

paralysis, sensory loss, or disturbance of muscle

tone. In contrast, the term dyspraxia is used to

describe motor planning defi cits that are developmental rather than acquired. Because diffi culties with motor actions are observable, dyspraxia

might be assumed to be a problem of motor execution. Ayres ( 1985 ), however, suggested that

dyspraxia was primarily a problem of organizing

the plan necessary for purposeful behavior. Ayres

 ( 1972b, 1985 ) believed that the ability to process

and integrate sensation formed the basis for the

development of body scheme. This, in turn, provided a foundation for the conceptualizations

needed for motor planning. Thus, occupational

therapists who view praxis from a sensory integrative perspective are concerned with individuals’ sensory processing and conceptual abilities

( Ayres, 1985 ; Cermak, 2011 ).

 Praxis and dyspraxia are complex concepts,

and the terminology associated with them can be

confusing. The lack of agreement as to what praxis

is and how it can be assessed continues to exist

today ( Steinman, Mostofsky, & Denckla, 2010 ;

116 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 Sugden, Kirby, & Dunford, 2008 ; Vaivre-Douret,

 2014 ). The term dyspraxia is sometimes applied

to children with developmental coordination

disorder (DCD), a term from the Diagnostic and

Statistical Manual of Mental Disorders (DSM)

referring to a neurodevelopmental disorder in

which motor performance “is substantially below

expected levels, given the person ’ s chronologic

age and previous opportunities for skill acquisition” ( American Psychiatric Association, 2013 ).

This condition may share characteristics common

to the concept of dyspraxia. Some use the terms

dyspraxia and DCD synonymously ( VaivreDouret, 2014 ), whereas others see dyspraxia as

a symptom and not a diagnosis ( Steinman et al.,

 2010 ). The poor motor performance may manifest as coordination problems, poor balance,

clumsiness, dropping or bumping into things,

or in the acquisition of basic motor skills (e.g.,

catching, throwing, kicking, running, jumping,

hopping, cutting, coloring, printing, writing).

These motor problems must interfere signifi -

cantly with activities of daily living (ADLs) or

academic achievement ( American Psychiatric

Association, 2013 ). The term dyspraxia refers to

developmentally based practic disorders with a

variety of etiologies, whereas somatodyspraxia is

identifi ed specifi cally as a practic defi cit having

its foundations in impairments in somatosensory

processing and related defi cits in body schema.

This distinction regarding the sensory foundations of the motor performance problem is not

typically recognized in much of the literature on

DCD. In this chapter, research related to children

with DCD will be examined along with children

with dyspraxia, as children with these diagnoses

are often one and the same. Furthermore, they

are often both seen by occupational therapists

using the sensory integration (SI) frame of reference to address similar or the same kinds of

defi cits.

Purpose and Scope

 In this chapter, sensory integrative-based practic

dysfunction, frequently referred to as dyspraxia by occupational and physical therapists,

is described as being manifested as diffi culties

in generating ideas for planning and organizing movement. Specifi cally, the characteristics

of praxis diffi culties are described in terms of

defi cits in ideation, somatodyspraxia, and bilateral integration and sequencing (BIS). Somatodyspraxia, BIS, and visuopraxis are recognized

subtypes of dyspraxia that are hypothesized to

refl ect aspects of practic defi cit distinguished primarily by their underlying sensory foundations.

Defi cits specifi cally in the ideational component

of praxis as a possible additional subtype are discussed. Sensory integrative-based disorders of

praxis have been identifi ed traditionally through

administration of the Sensory Integration and

Praxis Tests (SIPT; Ayres, 1989 ). This chapter

discusses the importance of assessment for determining different types of dyspraxia. This chapter

also presents symptoms of dyspraxia often seen

in children with other diagnoses, such as autism

spectrum disorder (ASD). Furthermore, because

of its pervasive effect not only on movement

but also on self-esteem and well-being, the

impact of dyspraxia on development, performance in ADLs, and socioemotional functioning

is described. The neuroanatomical mechanisms

purported to underlie praxis are reviewed, and SI

theory as it pertains to intervention for disorders

of praxis is discussed. Finally, related literature

that may be germane to sensory integrative-based

dyspraxia is examined. To illustrate the characteristics of practic disorders and important concepts of assessment and intervention, the cases of

two children, Alyssa and Dalton, are presented.

The Role of Sensation

in Movement and Praxis

 Knowledge of sensory processing is essential

to understanding sensory integrative-based dyspraxia. The performance of effi cient and precise

voluntary movement requires both the proper planning of movement parameters as well as the integration of sensory feedback ( Shumway-Cook &

Woollacott, 2011 ). Information regarding body

position in space necessary for praxis comes

from integration of numerous senses, including

tactile, proprioceptive, visual, vestibular, and auditory senses, as well as interceptive information

( Shumway-Cook & Woollacott, 2011 ). The brain

utilizes these inputs from several sensory systems

when planning movements and differentially prioritizes the application of these sensory inputs

depending on the task being performed ( Sober &

Sabes, 2005 ). There is more information on this

CHAPTER 5 Praxis and Dyspraxia ■ 117

multisensory process in Chapter 7 (Sensory Discrimination Functions and Disorders).

 Ayres ( 1972b ) asserted that motor planning

was dependent, in part, on the development of a

semiconscious body scheme or internal model of

the body in action that began with tactile awareness. “Sensory input from the skin and joints,

but especially from the skin, helps develop, in

the brain, the model or internal scheme of the

body ’ s design as a motor instrument” ( Ayres,

 1972b , p. 168). Ayres further suggested that

somatic changes arising from movement resulted

in motor memories that guided ensuing movements. Use of the body for action helped integrate the sensory information and develop the

body scheme. Thus, “if the information which

the body receives from its somatosensory receptors is not precise, the brain has a poor basis on

which to build its scheme of the body” ( Ayres,

 1972b , p. 170). Although Ayres ( 1972a, 1972b,

1985 ) emphasized the contribution of tactile and

proprioceptive sensation to the development of

body scheme (supported by more recent research

by Medina and Coslett, 2010 ), other investigators have noted important contributions of the

vestibular, visual, and auditory systems ( Daprati,

Sirigu, & Nico, 2010 ; Lopez, Schreyer, Preuss, &

Mast, 2012 ).

 The basics of sensory reception, transduction,

and processing within the sensory systems were

presented in Chapter 4 (Structure and Function

of the Sensory Systems). Praxis relies heavily

on discrimination within many sensory systems.

The links between praxis and sensory discrimination and integration are presented next,

whereas information regarding sensory discrimination function and dysfunction is presented in

 Chapter 7 (Sensory Discrimination Functions

and Disorders).

Tactile System

 As discussed in Chapter 4 (Structure and Function of the Sensory Systems), the tactile system

detects qualities and location of external stimuli

applied to the skin. More broadly, the somatosensory system subserves both perception and

action ( Dijkerman & de Haan, 2007 ). It conveys

information about the spatial and temporal characteristics of touch, is involved in tactile discrimination of touch and proprioception, and has been

linked to behaviors related to praxis ( Dijkerman

& de Haan, 2007 ; Lundy-Ekman, 2013 ; Serino

& Haggard, 2010 ). For example, signals from the

tactile system trigger exploratory behavior and

serve to guide movement for the purpose of gathering sensation. In addition, the somatosensory

system has been shown to be involved in postural

fl exion through activation of tonic labyrinthine

response, programming of complex movement

sequences, refi ned manual dexterity and manipulation, mental representation of objects, and

selective attention ( Serino & Haggard, 2010 ).

Contributions of the dorsal column medial

lemniscal (DCML) system to praxis are summarized in Table 5-1 . This pathway transmits

information relative to tactile discrimination,

deep touch, vibration, pressure, and muscle

and joint movement sensations from peripheral

receptors to the central nervous system (CNS).

Consistent with Ayres’ ( 1972a, 1972b ) views on

the importance of the somatosensory systems

in praxis, in a meta-analysis of motor learning,

 Hardwick, Rottschy, Miall, and Eickhoff ( 2013 )

found that specifi c loci of activity in the primary

somatosensory cortex were present in sensorimotor learning tasks, suggesting an active role

for this part of the cortex during motor learning.

In addition, the important fi nding that somatosensory representations are plastic and dynamically

changing in response to experience was reported

by Medina and Coslett ( 2010 ).

 Proprioception

 Proprioception refers to sensations of muscle

movement (i.e., speed, rate, sequencing, timing,

and force) and joint position ( Lundy-Ekman,

TABLE 5-1 Contributions of the Dorsal Column

Medial Lemniscal System to Praxis

MOTOR

SELECTIVE ATTENTION,

ORIENTATION, AND

ANTICIPATION

Initiation of voluntary

movements

Performance of complex

movement sequences and

refi ned manual dexterity

Handling objects in space

Flexion of joints

Unraveling competing

stimuli

Initiating and controlling

internal search

Anticipatory components

of sequential behavior

patterns

118 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 2013 ). Proprioception provides the motor system

with a map of the external environment and of

the body ( Blanche, Bodison, Chang, & Reinoso,

 2012 ). Knowledge of the body and movements

that come from proprioception are important for

the development of a body scheme, for praxis,

and for producing adaptive actions ( Ayres,

 1972b ; Blanche et al., 2012 ; Ito, 2012 ).

 Proprioceptive feedback arises primarily

from receptors in muscles, with some contributions made by receptors in skin and joints

( Lundy-Ekman, 2013 ). Golgi tendon organs and

muscle spindle receptors, the primary receptors for muscle proprioception, provide the

CNS with information about muscle changes

during movement, which, in turn, allows generation of the proper amount of force, timing,

and sequence of movements needed to act on

objects. The somatosensory cortex, in particular,

readily adapts to changing input, modifying the

body image and enabling skilled performance of

tasks ( Dijkerman & de Haan, 2007 ). Proprioception arising from active movement assists in the

development of body scheme and actions used

to plan complex movements ( Kiernan & Rajakumar, 2013 ). In contrast, passive movement, joint

compression, and joint traction do not produce

the same level of proprioceptive feedback ( Beets

et al., 2012 ). Thus, within an SI approach, active

movement is preferred over passive movement.

Vestibular System

 The vestibular system is thought to provide an

important sensory foundation for praxis, especially the development of bilateral coordination and planning of anticipatory movements

( Rine, 2009 ). The vestibular and proprioceptive

systems together contribute to the development

of balance, postural control, and integration of

postural refl exes ( Kandel, Schwartz, Jessell,

Siegelbaum, & Hudspeth, 2012 ). With its interconnections to the visual and auditory systems

and cerebellum, the vestibular system contributes

to posture and maintenance of a stable visual

fi eld, which allows effi cient awareness and

movement of the body through space ( Kandel

et al., 2012 ; Rine & Wiener-Vacher, 2013 ). In

conjunction with proprioceptive feedback, the

vestibular system contributes to the development

of neuronal models of how it feels to perform a

given movement ( Kandel et al., 2012 ; Kiernan

& Rajakumar, 2013 ), and these models are used

later to regulate ongoing activity and guide the

execution of future tasks ( Brooks, 1986 ). Defi -

cits in vestibular functioning have been found

to result in problems with motor development,

balance, and reading abilities ( Rine & Wiener-Vacher, 2013 ).

 Vision

 Vision is relevant to intervention based on SI theory

because of its important contribution to position

and movement in space. In combination with the

somatic senses (i.e., tactile, vestibular, and proprioceptive) that provide knowledge of the body

and its actions, vision yields much information

about the surrounding world ( Dionne, Legon, &

Staines, 2013 ). Vision provides a contextual

framework for the ability to predict and anticipate movement in time and space. In addition,

it allows the ability “to visualize one ’ s personal

space relative to where things of signifi cance are

in one ’ s world and what is possible with the available objects, people, and events” ( Kawar, 2005 ,

p. 89). Vision serves three major purposes: learning about objects and objects in space, maintaining posture, and informing us about our position

in space ( Kandel et al., 2012 ). The visual system

has strong neuroanatomical and functional connections to the vestibular system at the brainstem

and cortical levels ( Kandel et al., 2012 ), and the

ability to integrate sensory inputs from these two

systems is vital to one ’ s ability to move effectively in space. Ultimately, oculo-motor control

of eye movements, including saccades, pursuits,

and vergent movements, allows one to gather

meaningful information from the environment,

develop an understanding of objects and their

properties, and have spatial awareness.

 Ayres ( 1989 ) suggested that visual perception

and praxis are closely aligned and stated: “A conceptual system common to praxis also appears

to serve visual perception” (p. 199). Visualperceptual problems disturb the sensory information that children with motor coordination

problems receive, which, in turn, disturbs their

performance of planned movement ( Rosblad,

 2002 ). Thus, when all its functions are considered

together, vision infl uences cognition and plays a

signifi cant role in adaptation to the environment

and, in doing so, infl uences praxis. Ayres specifically identifi ed visuopraxis as a type of practic

CHAPTER 5 Praxis and Dyspraxia ■ 119

defi cit related in part to impairments in visual

perception and visuomotor function ( Ayres,

 1989 ). Similarly, in a retrospective study of

273 children tested on the SIPT, exploratory

factor analysis identifi ed a pattern similar to

the earlier research of Ayres, which the authors

referred to as Visuodyspraxia and Somatodyspraxia ( Mailloux et al., 2011 ). This factor was

characterized by high loadings on tests of visual

perception and visuopraxis, indicating the close

relationship among visual perception, visuomotor, and praxis functioning.

Auditory Processing

 Historically, auditory processing has not been

considered when addressing praxis. However,

research is increasingly supporting the relationship among the auditory system, the vestibular

system, and praxis; and increasing numbers of

occupational therapists are using sound-based

interventions to facilitate motor coordination

and praxis skills ( Gee, Devine, Werth, & Phan,

 2013 ). The auditory and vestibular systems are

functionally and neuro-anatomically interrelated.

Both respond to vibration, vestibular to low frequency vibration and auditory to high frequency.

Both sets of receptors are housed in the same

bony structure, and the fi bers carrying primary

auditory and vestibular inputs form a single

cranial nerve, CN VIII ( Kandel et al., 2012 ).

Similarly, it has been shown that there are close

interactions between the auditory and motor

systems, particularly for timing of movements

(J. L. Chen, Penhune, & Zatorre, 2008 ). This has

important implications for praxis.

 Processing of auditory inputs may contribute to the organization of movement because it

is responsible for providing information regarding the spatial location of objects and events.

Research linking the auditory system to praxis is

virtually nonexistent, but there are some studies

that suggest that the auditory system may be an

avenue for enhancing movement. Individuals

with neurological problems, such as Parkinson ’ s

disease, have consistently been found to improve

their gait with exposure to rhythmic auditory

inputs ( Plotnik et al., 2014 ). Also, literature on

musicians has supported that music and rhythmic tones are important in auditory-motor learning (J. L. Chen, Rae, & Watkins, 2012 ). Further,

studies with children with DCD have found that

spatial-temporal motor adaptation in these children is multisensory and that visual and auditory

sensory information was used to guide and adapt

motor movements (B. R. King, Kagerer, Harring,

Contreras-Vidal, & Clark, 2011 ). Warren, Wise,

and Warren ( 2005 ) also specifi ed the importance

of auditory inputs on motor sequencing, proposing that auditory feedback generated by motor

actions was important in motor adaptation and

allowed online monitoring of the auditory consequences of behavior.

HERE ’ S THE POINT

• Dyspraxia is not just a movement disorder;

it involves integration of sensory information.

• Numerous sensory modalities contribute to

development of an adequate body scheme,

which is important for motor planning.

• Research supports neural connections between

those that support praxis and those involved

in the processing of sensory information: the

vestibular, visual, tactile, proprioceptive, and

auditory sensory systems.

Assessing Disorders of Sensory

Integration and Praxis

 Praxis has been assessed using several measures. Using an SI frame of reference, the gold

standard assessment for children is the SIPT

( Ayres, 1989 ) as it assesses both motor planning and sensory processing. Other assessments

and research protocols that have been used to

examine praxis include asking the individual to

perform representational and nonrepresentational

gestures in response to verbal commands or imitation (following demonstration) ( Dziuk et al.,

 2007 ; MacNeil & Mostofsky, 2012 ) and motor

skill tests, such as the Bruininks-Oseretsky Test

of Motor Profi ciency (BOT-2; Bruininks &

Bruininks, 2005 ) or the Movement Assessment

Battery for Children—Second Edition (MABC-2;

 Henderson, Sugden, & Barnett, 2007 ).

 Poor performance on these tests may refl ect

dyspraxia, although other factors, such as poor

visual perception, also may infl uence performance or refl ect a visuodyspraxia. Ideational abilities may be assessed using the Test of Ideational

Praxis ( Ivey, Lane, & May-Benson, 2014 ; Lane,

Ivey, & May-Benson, 2014 ; May-Benson &

120 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

Cermak, 2007 ). Sensory histories, the Sensory

Profi le-2 ( Dunn, 2013 ), the Sensory Processing Measure ( Parham, Ecker, Miller Kuhaneck,

Henry, & Glennon, 2007 ), or the Sensory Processing Scale (SENSI; Miller & Schoen, 2012 )

may be used to gather information from parents

and teachers about impairments in sensory modulation and functional diffi culties experienced

by children. Although historically diffi cult to

assess in a standardized manner, Ayres ( 1972b )

identifi ed clinical observations as being important measures of postural, vestibular, and proprioceptive functions associated with praxis.

Based on Ayres’ ( 1972b ) original clinical observations, Blanche ( 2010 ) published a method

for observing a series of clinical observations

as well as a test for observing proprioceptive

processing with the Comprehensive Observations of Proprioception (COP) ( Blanche et al.,

 2012 ). Further, Wilson, Pollock, Kaplan, and

Law ( 2000 ) developed the Clinical Observation

of Motor and Postural Skills, and Horowitz has

published a test of Motor Observations ( http://

www.motorobservations.com ). More information

on assessment using clinical observations can be

found in Chapter 9 (Using Clinical Observations

within the Evaluation Process). Two case studies

are presented next in order to illustrate common

characteristics of dyspraxia and to demonstrate

the application of assessment methods.

CASE STUDY ■ ALYSSA

Reason for Referral

 Alyssa, a girl in fi rst grade, was 6 years and

4 months of age. Alyssa ’ s parents pursued

an occupational therapy evaluation from a

private occupational therapy clinic to investigate possible problems in SI. They wished

to clarify diffi culties she was having at home

with dressing and getting ready in the morning

and in school with pasting, coloring, cutting

with scissors, and printing. Alyssa ’ s evaluating occupational therapist interviewed Alyssa ’ s

parents, and her mother completed a comprehensive developmental and sensory history.

As school observation and teacher interview

were not possible, Alyssa ’ s teacher completed

a sensory questionnaire. The therapist administered the SIPT ( Ayres, 1989 ; see Chapter 8 ,

Assessment of Sensory Integration Functions

Using the Sensory Integration and Praxis Tests,

for more information on the SIPT), conducted

a variety of formal but nonstandardized clinical

observations of neuromotor performance (see

 Chapter 9 , Using Clinical Observations within

the Evaluation Process, for more information on clinical observations), and observed

Alyssa ’ s performance while playing on various

equipment in the clinic.

Parent Interview and Developmental/

Sensory History

 Alyssa was the product of a full-term pregnancy

and normal delivery. She weighed 6 lb, 8 oz at

birth and did not experience any neonatal diffi -

culties. She achieved developmental milestones

at expected ages: sat at 6 months, crawled at

8 months, and walked at 14 months. Her speech

developed normally with single words spoken

at 12 months and full sentences at 18 months;

mild articulation problems were noted but were

not of concern to her parents. As Alyssa got

older, her parents became concerned about her

lack of independence in dressing, eating, and

performing school activities, compared with

her older sister ’ s development.

 At home, Alyssa ’ s mother expressed

concern about her motor development, stating

that Alyssa was not yet dressing herself independently, was sloppy in eating, often knocked

over her water glass, and was not able to pedal

a tricycle until she was 5 years old. When dressing, Alyssa put her t-shirts on backwards and

her coat on upside down. She could not manage

the zipper on her coat or fasten the buttons on

her shirt (see Fig. 5-1 ). She was not yet walking

down stairs reciprocally, and she only recently

had learned to pump a swing. Even though she

struggled with new motor tasks, she tried hard

to do well. She wanted to be able to keep up

with her older sister and other children and play

the same games that they played.

 Although Alyssa played with other children

in the neighborhood, many of her friends were

younger than she was. Alyssa usually directed

the play with her friends toward quiet indoor

toys, such as puppets, dolls, and tea parties with

her toy dishes. When her friends did not want

to play her games, Alyssa was unable to play

alone. Her preferred activity was watching television. When her parents bought her toys that

required fi ne motor actions, such as dressing up

CHAPTER 5 Praxis and Dyspraxia ■ 121

dolls or stringing beads to make a necklace, she

created fantasy games that re-enacted stories

or movies instead of using the toys in more

typical ways. Alyssa had a vivid imagination

and loved to tell stories. She appeared to be

highly creative but often could not demonstrate

the actions she described.

Teacher Questionnaire

 According to her teacher, Alyssa had diffi culty

with writing, coloring, and cutting with scissors

compared with her classmates. Alyssa ’ s teacher

reported that Alyssa could print her name but

was not yet able to copy simple words, even

when the letters were the same as those in her

own name. Alyssa pressed the pencil so hard

on the paper that often the point broke. When

given a 20-piece puzzle, Alyssa was able to

determine the correct location for the pieces

but was unable to fi gure out how to rotate them

into place. The teacher reported that Alyssa had

excellent verbal skills, which was consistent

with information provided by her mother and

other observations made by the therapist.

FIGURE 5-1 Dressing skills, including donning

clothing and manipulating fasteners, may

be particularly challenging for children with

somatodyspraxia and one of the fi rst problems

parents may notice.

 Because Alyssa ’ s daily life concerns potentially refl ected a sensory integrative basis, she

was administered the SIPT and clinical observations of neuromotor performance. We present

the results of this testing in fi ve categories:

 1. Tactile discrimination

 2. Vestibular and proprioception processing

 3. Praxis

 4. Form and space, visual-motor, and

construction

 5. Sensory modulation

 Alyssa was cooperative with the evaluator

throughout the administration of the SIPT; her

SIPT scores are shown in Table 5-2 . Even on

items that were diffi cult for her, she attempted

to do a good job. She especially did not like

the tests that involved building with blocks

and fi nding hidden pictures. When observed in

the sensory-motor treatment room, she became

frustrated when asked to come up with ideas

for play.

 Tactile, Vestibular, and Proprioceptive Processing

 Alyssa ’ s SIPT scores were signifi cantly low

(less than or equal to –1.0 SD) on three of four

tactile tests. Relative to proprioception, her

ability to remember the direction and extent

of passive arm movements (KIN) was in the

low average range, but the duration of her

Postrotary Nystagmus (PRN) was within the

average range. She showed inadequate static

and dynamic balance abilities (SWB), her equilibrium responses were slightly delayed, she

tended to hold on to the examiner rather than

use equilibrium to maintain balance, and clinical observation revealed that Alyssa had low

muscle tone and poor proximal joint stability

and was unable to assume prone extension or

maintain head control while in supine fl exion.

Alyssa did not demonstrate any avoidance

responses to touch, and neither her mother nor

her teacher reported any indications of tactile

defensiveness. She did not have any evidence

of gravitational insecurity or aversive responses

to movement. No indication of a drive or

craving for increased sensory input was noted.

 Praxis

 One of Alyssa ’ s lowest scores on the entire

SIPT was on Postural Praxis, a test of the

ability to reproduce unusual hand, arm, and

122 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

TABLE 5-2 Alyssa ’ s SIPT Results

CATEGORY TEST STANDARD SCORE

Tactile Manual Form Perception (MFP) –1.3

Localization of Tactile Stimuli (LTS) 0.7

Finger Identifi cation (FI) –1.9

Graphesthesia (GRA) –1.8

Vestibular and

 Proprioceptive

 Processing

Kinesthesia (KIN) –0.8

Standing and Walking Balance (SWB) –2.1

Postrotary Nystagmus (PRN) –0.2

Praxis Postural Praxis (PPr) –2.3

Oral Praxis (OPr) –1.4

Sequencing Praxis (SPr) –1.4

Bilateral Motor Coordination (BMC) –1.3

Praxis on Verbal Command (PrVC) 0.1

Form and Space, Visual-Motor,

Construction

Design Copying (DC) –1.9

Motor Accuracy (MAC) –1.8

Constructional Praxis (CPr) 0.6

Space Visualization (SV) 1.2

Figure-Ground Perception 0.9

body postures and an important indicator of

dyspraxia. Movement sequencing and bilateral coordination were below average. Alyssa ’ s

ability to replicate positions and movements of

her tongue, lips, and jaw (Oral Praxis [OPr])

was also below average. However, Alyssa

was able to carry out movements on verbal

command, which often is the case for children

with somatodyspraxia who have good understanding of language. On paper-and-pencil

tasks, Alyssa showed a right hand preference

and used a static tripod grasp. She was able

to perform sequential thumb-to-fi nger touching with her right or left hand only by visually

monitoring her fi ngers; thus, she could not do it

with both hands simultaneously. Alyssa ’ s performance was immature, but it was striking that

she could perform the action well as long as she

could visually monitor her fi ngers.

 Form and Space, Visual-Motor, and Construction

 Alyssa ’ s ability to trace a line with a pen

(Motor Accuracy [MAC]) and to reproduce

two-dimensional forms (Design Copying [DC])

was below age expectations, suggesting diffi culty with visual-motor control. The rest of

Alyssa ’ s SIPT scores in this category suggested

age-appropriate form and space perception and

constructional abilities.

 Related Testing and Summary

 Psychological assessment revealed that Alyssa ’ s IQ score was 132, with a higher verbal

than performance IQ. Given her competence

with language skills compared with her poorer

visual-motor and motor planning skills, we

were not surprised that her verbal IQ was

higher. A signifi cant difference between verbal

and performance IQ score, with lower performance scores, fi ts a common pattern seen in

children with dyspraxia.

 From the overall pattern of test scores and

observations, the occupational therapist identifi ed somatodyspraxia as a major factor that

interfered with Alyssa ’ s performance. Alyssa ’ s dyspraxia appeared to have its basis in

poor processing of tactile and vestibularproprioceptive sensation. Alyssa ’ s dyspraxia

involved both gross and fi ne motor (visualmotor) components. She also appeared to have

diffi culties with the ideational aspect of praxis.

CHAPTER 5 Praxis and Dyspraxia ■ 123

CASE STUDY ■ DALTON

Reason for Referral

 Dalton was a 7 1/2-year-old boy attending

second grade at a local public school. Dalton ’ s teacher reported that he moved about in

his seat frequently, often stood up instead of

staying seated, and had diffi culty paying attention in class. At recess, she reported he was

very active, often playing chase and tag games.

Sometimes he was unintentionally aggressive

with other children, pulling or pushing them to

get them to participate in his games. Although

he was quite bright and most of his work was

at grade level, he had to try very hard to keep

up with his classmates. His handwriting was

diffi cult to read and, in frustration, he often

scribbled carelessly on his papers. The teacher

requested an evaluation from the school occupational therapist. Dalton ’ s parents were surprised at the teacher ’ s request for an evaluation

because they believed he was bright and would

do well in school. The occupational therapist

who evaluated Dalton interviewed his teacher

and his parents who also completed a comprehensive developmental and sensory history. The

occupational therapist administered the SIPT

( Ayres, 1989 ), observed Dalton during a variety

of formal but nonstandardized clinical observations of neuromotor performance, and observed

his performance in the classroom.

Parent Interview and Developmental/

Sensory History

 Dalton ’ s mother experienced a great deal of

nausea during her pregnancy. Dalton was

delivered by cesarean section, but no postnatal complications were apparent. His mother

described him as a happy but active baby who

had poor sleep habits. He crawled only briefl y,

and walked at 9 months. He began using language before age 1 year. As a preschooler,

Dalton had several ear infections but was otherwise healthy. No particular sensitivities to

auditory or tactile stimuli were reported, but

Dalton was easily distracted. He was having

diffi culty learning to ride his two-wheeled

bicycle and struggled with tasks using both

hands, such as buttoning his shirt and tying

his shoes. Dalton liked to play soccer, but his

mother noted that he frequently tripped on the

playing fi eld and could not time his kicking

actions appropriately. Often he was observed

randomly jumping and running during games.

He was initially enthusiastic when trying new

tasks, but he quickly lost interest when things

did not go well. His mother described Dalton

as a “thrill seeker,” stating he often engaged in

risky behavior, such as climbing to the top of

their swing set and trying to crawl across it. He

was generally happy and seldom daunted by his

poor coordination.

Teacher Interview

 According to his teacher, Dalton sat near the

front of the classroom and did a great deal of

fi dgeting and wiggling in his seat. He often

looked around at classmates and dropped

things on the fl oor. Dalton generally preferred

his right hand for writing but often used his left

hand for other tools, such as a fork. He used all

fi ve fi ngers of his right hand to hold the pencil,

stabilizing it against his little fi nger. Dalton

used scissors awkwardly with his left hand and

struggled to hold the paper in his right. Associated movements were noted in his right hand

that mirrored the actions of his left hand. At

times, he transferred the scissors to his right

hand. He resorted to tearing the paper when he

could not maneuver the scissors well.

 As in the case of Alyssa, because Dalton ’ s

daily life concerns appeared to have a sensory

integrative basis, relevant clinical observations

and the SIPT were administered. The results of

his testing are presented next.

 Dalton was eager to try many of the tasks

requested by the occupational therapist, and

although he was fi dgety, he was attentive

throughout the one-on-one evaluation. None

of his scores refl ected severe impairments in

performance. In fact, many of his scores on the

SIPT were within normal limits. However, the

pattern of low scores, coupled with a meaningful cluster of clinical observations, is typical

of children with BIS defi cits. Dalton ’ s lowest

scores are reported in Table 5-3 .

 Tactile, Vestibular, and Proprioceptive Processing

 Dalton did well on most of the tests requiring tactile discrimination. The one exception

was Graphesthesia (GRA), which required fi ne

motor skill and two-sided body use in addition

to tactile discrimination. He exhibited low proximal muscle tone and hyperextensibility of his

124 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

elbows, wrists, and fi ngers. He could not assume

prone extension or maintain his head position in

supine fl exion. Dalton displayed poor postural

background movements and equilibrium reactions. These factors, coupled with low scores

on Kinesthesia (KIN), Standing and Walking

Balance (SWB), and PRN, suggested poor

vestibular-proprioceptive processing. Dalton

also did not exhibit aversive reactions to touch

or movement. He was, however, distractible

and impulsive when observed in unstructured

situations and in group activities, such as

playing soccer.

 Praxis

 Although his SIPT scores were within the

average range, Dalton ’ s lowest SIPT scores were

on the Bilateral Motor Coordination (BMC)

and Sequencing Praxis (SPr) tests, and the Postural Praxis (PPr) test was in the low average

range. Clinical observation revealed that tasks

requiring bilateral coordination (e.g., jumping

jacks, reciprocal stride jumps, and skipping)

were poorly coordinated and performed with

a great deal of effort. Dalton could not consistently identify his left and right body sides. He

carefully monitored isolated movements of his

forearms, hands, and fi ngers with his eyes and

moved very slowly when performing simultaneous movements with both hands. In addition,

he had a problem controlling his body when

jumping through a sequence of squares taped

on the fl oor, throwing and catching balls, and

kicking balls that were rolled to him.

 Form and Space, Visual-Motor, and Construction

 Dalton had diffi culty with the MAC test, a penand-paper task requiring fi ne motor control.

This score is consistent with his handwriting

diffi culties.

 Summary

 From the overall pattern of test scores and

observations, the occupational therapist determined that Dalton demonstrated diffi culties

with BIS. He demonstrated particular diffi culties with anticipating body actions and projecting his body through space, both of which

impacted his ability to be successful in sports.

Dalton ’ s praxis diffi culties appeared to have

their basis in poor processing of vestibularproprioceptive sensory inputs, which involved

his postural control, bilateral coordination, and

fi ne and gross motor sequencing skills.

 Both Alyssa and Dalton showed behaviors consistent with sensory integrative-based

practic disorders. The behaviors are notable in

their reasons for referral, observations made in

the classrooms, parental reports of behavior at

home, and standardized testing.

HERE ’ S THE POINT

• Praxis has been assessed through several

measures, with the SIPT ( Ayres, 1989 ) being

the gold standard for those using an SI

framework.

• Clinical observations of postural and motor

skills are an important adjunct to standardized

assessment.

Disorders of Praxis

Patterns of Practic Dysfunction

 Through time, using different samples of children and various types of factor analyses, Ayres

alone ( 1965, 1966, 1971, 1977, 1989 ) and with

her colleagues ( Ayres et al., 1987 ) identifi ed consistent patterns of practic dysfunction. She identifi ed a link between tactile functions and motor

planning as well as a relationship between

visual-spatial skills and motor planning. In some

analyses, she also identifi ed postural, bilateral

integration, as well as motor sequencing problems linked to vestibular processing. Ayres ( 1989 )

TABLE 5-3 Dalton ’ s Lowest SIPT Scores

TEST STANDARD SCORE

Kinesthesia (KIN) –1.2

Graphesthesia (GRA) –1.0

Postural Praxis (PPr) –0.9

Bilateral Motor Coordination

(BMC)

–1.4

Sequencing Praxis (SPr) –1.3

Standing and Walking Balance

(SWB)

–1.1

Motor Accuracy (MAC) –1.2

Postrotary Nystagmus (PRN) –1.2

CHAPTER 5 Praxis and Dyspraxia ■ 125

ultimately identifi ed four major patterns of dysfunction in praxis, which she labeled as:

 1. Somatodyspraxia

 2. BIS defi cits

 3. Dyspraxia on verbal command

 4. Visuodyspraxia (sometimes combined

with somatodyspraxia to be called

visuo-somatodyspraxia )

 Mulligan ( 1998 ) subsequently performed factor

analyses using more than 10,000 SIPT profi les

of children evaluated for possible sensory integrative problems. She identifi ed a factor refl ecting generalized sensory integrative dysfunction

and four fi rst-order factors that bear similarity

to Ayres’ dysfunctional groups. Mulligan labeled

the fi rst-order factors:

 1. BIS defi cit

 2. Dyspraxia (including all praxis tests

except BMC and SPr, even those refl ecting

primarily cortical function, such as Praxis on

Verbal Command)

 3. Somatosensory defi cit

 4. Visuoperceptual defi cit

 More recently, in an exploratory factor analysis using the SIPT and items from the Sensory

Processing Measure, Mailloux and colleagues

 ( 2011 ) identifi ed patterns similar to those found

by Ayres. They identifi ed patterns of visuodyspraxia, somatodyspraxia, vestibular and proprioceptive bilateral integration and sequencing,

tactile and visual discrimination, and tactile

defensiveness and attention.

 Using a somewhat different approach, MayBenson ( 2005 ) examined patterns of practic

dysfunction related to the ideational aspect of

praxis, an area that had not been addressed in

any of the previous pattern analyses of praxis.

She conducted a cluster analysis on three groups

of age- and gender-matched children (children

with motor planning problems alone, with motor

planning and ideational problems, and typical

peers). Tests included those of motor coordination, ideation, motor planning, language, behavior, and executive function. She identifi ed fi ve

cluster groups, two of which refl ected average

and above average skills. Practic defi cits were

identifi ed in the other cluster groups by general

order of severity:

• Generalized dysfunction—low scores on all

tests.

• Dyspraxic group—average ideation scores

but below average motor coordination

and motor planning skills, attention and

behavioral regulation, and average language

skills.

• Ideational dyspraxic group—well below

average ideational skills (below those of

generalized dysfunction), below average

motor coordination and manual motor skills,

but average fi nger tapping and imitation of

hand skills, below average attention and

behavioral regulation, average executive

planning, and above average language skills.

 Thus, ideational diffi culties, although clearly

related to motor planning problems, likely represent an additional aspect of dyspraxia.

 Ayres ( 1989 ) sought to differentiate among

patterns and subtypes of practic dysfunction as

a step toward developing intervention strategies tailored to the individual child. Additional

research using the SIPT by Ayres, Mailloux, and

Wendler ( 1987 ) and Lai, Fisher, Magalhães, and

Bundy ( 1996 ) strongly suggests that praxis likely

is a unidimensional construct that may practically distinguish between different aspects of

practic defi cit. Using the Rasch analysis, Lai and

colleagues ( 1996 ) found that SIPT praxis tests

associated with BIS were more diffi cult than

those associated with somatodyspraxia, suggesting that BIS may represent a less severe form of

practic disorder and that somatodyspraxia and

BIS may be viewed as two aspects of the same

dysfunction. May-Benson ( 2005 ) suggested that

ideational problems may exist with or without

concomitant motor planning problems. Clearly

sensory-based dyspraxia is manifested in several

ways in different children. Thus, the clearest

interpretation of an individual child ’ s profi le

might be to say that there is evidence refl ecting

generalized sensory integrative dysfunction with

particular defi cits in sensory processing, ideation,

or aspects of motor planning.

Ideational Dyspraxia

 Ayres ( 1985 ) stated,

 Ideation or conceptualization is central to the

theory of dyspraxia. . . . [It] is a cognitive or

thinking process. Before one can engage purposefully or adaptively with a physical object,

large or small, one must fi rst have the concept of possible person-object interaction. . . .

126 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

Ideational praxis is an essential skill underlying

all use of objects to obtain a goal that may or

may not be independent of the objects. (p. 20)

 She further stated that ideation involves conceptualizing the goal for an action and some idea

of how to achieve that goal. Ideation, therefore,

involves both generating a goal and identifying the general steps needed to accomplish that

goal ( Ayres, 1985 ). Further, ideation is largely a

cognitive process that ultimately contributes to

a child ’ s ability to be creative and playful as he

or she interacts with the environment. Ideation

is an important foundational ability for pretend

play as seen in children with ASD ( Rutherford &

Rogers, 2003 ).

 Problems in ideation have historically been

thought to occur in children with severe dyspraxia and most often in those with cognitive

or intellectual delays ( Ayres, 1985 ), and little

has historically been known about these children. More recently, May-Benson ( 2005 ) found

that ideational problems existed independent

of motor planning problems and were identifi able in nearly half of her population of children with dyspraxia, indicating that ideational

diffi culties are more prevalent than previously

believed. Children with ideational problems were

found to have fewer or less complex ideas for

actions. In addition, in examining the characteristics of children with ideational problems, MayBenson ( 2005 ) further found that a subgroup had

above-average intelligence and language skills,

thus indicating that although ideational diffi culties may occur in individuals with cognitive defi -

cits, it is not a necessary condition for ideational

dyspraxia.

 Characterizing ideational defi cits in children

relies heavily on what has been observed clinically. Literature relative to ideational defi cits

in adults is presented in the text that follows,

and many of the characteristics described here

are extrapolated from this knowledge base

( May-Benson, 2000 ). Children with ideational

defi cits are often observed to have diffi culty

knowing what to do, even with familiar toys

and objects. They may stand and watch others,

avoid participation in free play activities, or be

followers instead of leaders. They have a limited

repertoire of actions with which to interact with

the world, and they tend to repeat those actions

instead of trying new ways to approach a task.

They do not recognize which actions are afforded

by which object properties and, therefore, often

use objects in inappropriate ways. Play skills are

observed to be particularly diffi cult for children

with ideational problems. They have diffi culty

representing objects; thus, creative or imaginative play is adversely impacted. Some children

with ideational problems may do well with structured play, such as sports, but have diffi culties

with free-play situations. Some children with

ideational problems, such as Alyssa, use their

imagination to tell stories but struggle with conceptualizing ways to act on objects. In Alyssa ’ s

case, her high intelligence may have supported

her story making and language abilities, but she

could not engage in dynamic physical interactions using her body. She was intelligent enough

to know that she did not perform as well as her

peers and compensated by seeking younger companions and sedentary play.

 Somatodyspraxia

 Somatodyspraxia is characterized by poor planning of both movements that are anticipatory and

feedforward-dependent as well as actions that

depend on sensory feedback. Therefore, children with somatodyspraxia exhibit diffi culties

with planning the same kinds of tasks that are

problematic for individuals with defi cits in BIS

as well as some generally easier tasks ( Ayres,

 1989 ). Children with somatodyspraxia generally

show a characteristic pattern of test scores on the

SIPT and clinical observations ( Ayres, 1989 ).

Low scores commonly noted on the SIPT are

PPr, BMC, SPr, and OPr. Alyssa had low scores

on all these measures. Constructional Praxis

(CPr) and Praxis on Verbal Command (PrVC)

scores may also be low, as may DC and MAC,

refl ecting problems in visual spatial skills. Motor

skills that are often diffi cult for individuals with

somatodyspraxia include the ability to assume

supine fl exion, sequential fi nger touching, the

ability to perform rapid alternating movements

(diadokokinesis) (see Chapter 9 , Using Clinical

Observations within the Evaluation Process), and

in-hand manipulation skills ( Exner, 1992 ). Alyssa

demonstrated most of these diffi culties. Further,

interviews with parents and teachers often report

diffi culties related to daily routine. Delays in the

acquisition of self-care skills, poor organization,

diffi culty manipulating and assembling toys, and

strained relationships with siblings or playmates

(or a history of these) are commonly reported.

CHAPTER 5 Praxis and Dyspraxia ■ 127

 For somatodyspraxia to have a sensory integrative basis, it must be accompanied by evidence

of poor somatosensory and sometimes vestibular

or proprioceptive processing. Alyssa and many

others with somatodyspraxia have low scores on

tactile tests of the SIPT, including Manual Form

Perception, Finger Identifi cation, and Localization of Tactile Stimuli. Because defi cits in BIS

based in poor vestibular and proprioceptive

processing seem to represent a higher level of

practic dysfunction than somatodyspraxia ( Lai

et al., 1996 ), it is reasonable to suspect that many

clients with somatodyspraxia will also have diffi culty with measures of vestibular and proprioceptive processing. In addition, some children

with somatodyspraxia demonstrate visual-spatial

problems resulting in a visuo-somatodyspraxia.

Bilateral Integration and Sequencing

(BIS) Defi cits

 BIS problems appear to be a relatively mild form

of practic disorder; thus, BIS defi cits are generally subtle. They involve poorly coordinated

use of the two body sides, defi cits in performing sequences of movement, and usually poor

postural-ocular skills. BIS defi cits that are

sensory integrative in nature are hypothesized to

refl ect impaired processing of vestibular and proprioceptive sensations and to have their foundation in poor postural-ocular skills ( Ayres, 1985 ;

 Mailloux et al., 2011 ). Although literature supporting a direct neurophysiological link between

vestibular dysfunction and bilateral coordination

skills is minimal, there is support for a relationship between vestibular functioning and postural mechanisms ( Lin et al., 2012 ; Majernik,

Molcan, & Majernikova, 2010 ; Peterka, Statler,

Wrisley, & Horak, 2011 ). Further, vestibular

inputs are important for the use and integration

of many postural refl exes, such as the tonic labyrinthine refl ex and asymmetrical tonic neck

refl ex, among others ( Kandel et al., 2012 ).

 Bilateral coordination diffi culties are routinely found in conjunction with diffi culties

with projected action sequences or anticipatory

actions involving timing and movement through

space. Projected action sequences, which include

actions such as running across a fi eld to catch

a ball, have their basis in vestibular and proprioceptive inputs and rely heavily on the integration of visual and movement sensory inputs

( Schaaf et al., 2010 ). Therefore, during clinical

observations, a child who has BIS defi cits may

demonstrate right–left confusion; poor lateralization of hand function; avoidance of midline

crossing; and poor ability to do motor skills

such as skipping, jumping jacks or stride jumps,

riding a bicycle, catching or throwing a ball,

cutting with scissors, or stabilizing one ’ s paper

when writing. Oculo-motor diffi culties, such as

problems with visual tracking, convergence, and

saccades, are routinely found with this problem.

On the SIPT ( Ayres, 1989 ), scores on BMC and

SPr are generally low in conjunction with low

scores on PRN and SWB. Ayres also found low

scores on GRA and OPr to be associated with

defi cits in BIS as they involve motor sequencing. These measures are described more fully in

 Chapter 8 (Assessment of Sensory Integration

Functions Using the Sensory Integration and

Praxis Tests). Dalton ’ s SIPT scores refl ect this

pattern. His lowest scores were on BMC and SPr,

and he had diffi culty with all clinical observations that refl ect BIS. Other motor assessments

may refl ect diffi culties in balance skills, ball

skills, and gross and fi ne motor coordination tasks

(see Fig. 5-2 ).

HERE ’ S THE POINT

• Patterns of practic dysfunction remain

relatively consistent across studies and include

somatodyspraxia, BIS problems, ideational

dyspraxia, and related visuopraxis and visuospatial defi cits.

FIGURE 5-2 Children with BIS may have diffi culty

coordinating their upper extremities to push and pull

themselves while on a scooter.

128 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

• Children with ideational problems have

diffi culties generating goals for ideas and

some idea of how to achieve the goal.

• Children with somatodyspraxia typically

have problems with processing tactile and

proprioceptive sensory inputs and have

diffi culties with motor planning, which may

be seen in conjunction with visual-spatial or

visuopraxis problems.

• Children with BIS diffi culties have problems

processing vestibular-proprioceptive inputs and

have diffi culties coordinating two parts of the

body, sequencing actions, and anticipating

actions.

Neuroanatomical Bases of Praxis

 The neuroanatomical aspects of the sensory

systems are described in Chapter 4 (Structure

and Function of the Sensory Systems). This

section examines the neuroanatomical underpinnings specifi c to praxis and discusses areas of

the brain thought to be involved in conceptualizing, planning, sequencing, and initiating action,

all important components of praxis. Although

many regions of the brain contribute to praxis,

there are no neuroanatomical loci clearly and

uniquely implicated in developmental dyspraxia.

Diffi culty localizing a specifi c neurological

“substrate” or “locus” for developmental clumsiness supports the viewpoint posited by Luria

 ( 1963, 1980 ), Tracy and colleagues ( 2003 ), and

 Hardwick and colleagues ( 2013 ) that praxis is

dependent upon a complex functional system or

network involving cortical and subcortical structures with different brain structures participating

in different phases of motor learning.

 Despite the absence of a clearly defi ned praxis

loci or pathway, there are, nonetheless, functional

and structural differences identifi ed by lesion

studies, motor learning studies, and by functional

magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) in typical adults and

in adults with apraxia. However, although we

can draw upon this information, it is likely that

the mechanisms underlying developmental dyspraxia are not the same as those in the adult with

known acquired brain injury.

 In the next section, brain structures believed

to be associated with ideation, planning, and execution of action are examined.

 Ideation

 Ideation has been identifi ed as a cortical function that involves conceptualization of “knowing

what to do” in motor actions ( Jeannerod &

Decety, 1995 ), but the process of ideation is still

not well understood. In adult apraxia, ideational

apraxia is described variably as a problem in

both pantomiming and imitating object use or

as a problem with sequential use of objects; in

both cases, the primary defi cit is believed to be

a problem with having the “idea” or conceptualization of the motor action ( Roy et al., 2014 ).

In children, ideational defi cits are viewed more

broadly as a defi cit in generating a goal for an

action and some idea of how to achieve the goal

( Ayres, 1985 ). May-Benson ( 2001 ) proposed that

the ability to generate ideas for action was the

result of interactions of the person with objects or

the environment. Ideas for action were thought to

originate, in part, from external sensory stimuli

and internal models or memories of past experiences. The abilities to represent motor actions

and generate motor images were identifi ed as

vital components of the ideation process ( Brooks,

 1986 ; Gentsch, Weber, Synofzik, Vosgerau, &

Schütz-Bosbach, 2016 ). Cognitive functions of

knowledge of objects, knowledge of actions,

knowledge of serial actions, and knowledge of

appropriate object-action interactions were identifi ed as being necessary for the effective development of ideas for actions ( Roy et al., 2014 ).

 As with praxis in general, ideation cannot be

localized to one area of the brain. Studies with

adults with strokes who have apraxia and associated ideational defi cits demonstrate damage

to the left hemisphere ( Harrington et al., 2000 ).

 Malkani and Zadikoff ( 2011 ) proposed that ideational apraxia in adults was related to damage

to the left parietal-occipital (region around where

the parietal and occipital lobes meet) and parietotemporal regions (region around where the parietal and temporal lobes meet) of the brain as well

as possible areas in the left frontal regions (see

 Fig. 5-3 ). Importantly, these regions correspond

to visual-somatosensory and visual-auditory

integration areas. Thus, primary sensory areas, in

particular the left parietal areas, receive sensory

inputs, and association areas integrate information and establish necessary spatial-temporal

information for action. The prefrontal cortex

plays a major role in setting goals and is active

when we perform (or even imagine performing)

CHAPTER 5 Praxis and Dyspraxia ■ 129

complex, goal-directed sequences of movements,

particularly in novel situations ( Fuster, 2008 ).

The supplemental motor area (SMA) organizes

actions and is proposed to be involved in goal

recognition and motor imaging of actions. Indirect connections for ideation with the limbic

system, basal ganglia, and cerebellum may also

play some role in accessing information for idea

generation, imaging, organization of action, and

initiation ( May-Benson, 2001 ). Future research

using brain imaging technology is needed to specifi cally examine which structures are involved

in ideation.

Planning, Motor Learning,

and Execution

 Various aspects of the brain are involved in

motor planning and motor learning. In a quantitative meta-analysis and review of the functional

imaging literature of motor learning in typically functioning right-handed adults, a bilateral

cortical-subcortical network was consistently

found to underlie motor learning ( Hardwick

et al., 2013 ). Brain regions in this network

included the dorsal premotor cortex (dPMC),

SMA, primary motor cortex, primary somatosensory cortex, superior parietal lobe, thalamus, putamen, and cerebellum ( Hardwick et al.,

 2013 ). Further, activity in the basal ganglia and

cerebellum was stronger for sensorimotor tasks

that emphasized the learning of novel movement

kinematics and dynamics. Consistent activation

of the left dPMC across multiple activities suggested it plays a critical role in motor learning.

 Both the lateral premotor cortex (lPMC) and

medial SMA play important roles in the translation of a movement strategy into movement

tactics (the “how to do it”) ( Purves et al., 2012 ),

selection of appropriate movements ( ShumwayCook & Woollacott, 2011 ), and other features

of motor planning ( Hardwick et al., 2013 ).

The lPMC is active when movement occurs in

response to external events (e.g., a driver stops

when a traffi c light changes from green to red)

( Shumway-Cook & Woollacott, 2011 ). The SMA

depends primarily on proprioceptive inputs and is

activated when action is self-initiated ( ShumwayCook & Woollacott, 2011 ). The PMC has also

been shown to play a role in the preparation

and anticipation of movement ( Lohse, Wadden,

Boyd, & Hodges, 2014 ; Purves et al., 2012 ). See

FIGURE 5-3 Regions of the cortex showing the parietal, occipital, temporal, and frontal lobes, as well as the

primary motor, primary sensory, and prefrontal regions.

Temporal

lobe

Prefrontal

area

Premotor area

Supplementary

motor area

Auditory

association

area

Visual association

area

Visual

cortex

Frontal

lobe

Occipital

lobe

130 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

the box, Here ’ s the Evidence, for more information regarding the work by Lohse and colleagues.

 Areas 5 and 7 of the parietal cortex (see Fig. 4-7

for details of these numbered Brodmann ’ s areas)

are other major sites of convergence of bilateral

somatosensory inputs from the body with input

from other sensory systems ( Dijkerman & De

Haan, 2007 ). Indirect vestibular signals may also

project to area 5. There is evidence that cells

in area 5 begin fi ring before movement is initiated and then continue to fi re even under conditions of deafferentation and immobilization of

joints ( Dijkerman & De Haan, 2007 ). This suggests that some of these cells may play a role in

planning active movement ( Kandel et al. 2012 ).

Area 5 has close connections with precentral

motor areas, including the SMA, further suggesting a role of proprioceptive inputs to motor planning ( Kandel et al., 2012 ). Activity is also shown

in area 7A of the parietal cortex (superior parietal

lobule or SPL) during motor learning. Hardwick

and colleagues ( 2013 ) suggested that the superior

parietal lobe integrates visual and somatosensory

inputs and routes these multimodal outputs to the

dPMC, a key hub for motor learning.

 The basal ganglia receives signifi cant input

from the SMA and, via the thalamus, projects

back to this region. The basal ganglia participates

in the initiation of movement, but its role may

be dependent on context—that is, it may play

its role when movements are complex enough

to require sequencing (Lundy-Ekman, 2013).

Although basal ganglia neurons are active at the

onset of movement, their activity increases after

movement initiation. Thus, the basal ganglia

are most important in the completion of movement. The functions of the basal ganglia are not

limited to motor behavior and include emotional,

motivational, and associative, as well as cognitive functions (Lundy-Eckman, 2013; Nelson &

Kreitzer, 2014 ). The ventral system of the basal

ganglia receives information primarily from the

limbic system. These connections may subserve

motivation and emotion important to praxis.

 The cerebellum receives primary sensory

inputs from the vestibular system and has a major

role in both the planning and execution of coordinated movement. It serves to compare actual

and expected sensory outcomes of movements

and determines if changes to the motor command

must occur to achieve the desired response.

The cerebellum regulates the timing and force

of movements to allow smooth, accurate, and

rapid movements through feedforward control

of muscle contractions ( Kandel et al., 2012 ), and

plays an active role in motor planning.

 Ito (2012) suggested that cerebral cortical

models of movements and actions are developed

during the initial learning of motor actions. He

posited that internal cerebellar models or action

schemas are developed based on body schemas

(continually undated maps of one ’ s body shape

and posture) and motor schemas (one ’ s longterm memories of movement that are retrieved

and control further complex actions and motor

skills). Research by Schmahmann, Anderson,

Newton, and Ellis ( 2002 ) found that the cerebellum also plays a vital role in cognition skills,

such as constructing “intentional representations

of the world and our bodily activities in the

world.” These authors stated that the cerebellum

is essential for an individual ’ s ability to fully

realize self-conscious sensorimotor experiences.

This viewpoint is consistent with SI theory that

one must “internalize” body actions to effectively and adaptively move in the environment.

In addition, the ability to represent one ’ s world

and actions is believed to be vital for the development of ideational abilities. Other researchers have found that the cerebellum also plays a

role in neurocognitive development, executive

HERE ’ S THE EVIDENCE

In a recent review (meta-analysis) of skill acquisition in healthy adults using neuroimaging as

a function of length of practice, Lohse and colleagues ( 2014 ) reported that across time scales,

there were consistent decreases in activity in

the prefrontal and premotor cortex, the inferior

parietal lobes, and the cerebellar cortex, indicating that these areas may be most important in

the earlier learning phase. Similarly, across time,

increases were noted in the supplementary and

primary motor cortex and dentate nucleus. At

the longest time scale, increases were seen in the

posterior cingulate gyrus, primary motor cortex,

and striatum (putamen and globus pallidus).

Further, activity in the striatum was more rostral

in the medium time scale and more caudal in

the longer time scale. These data support the

fact that both a cortico-cerebellar system and a

cortico-striatal system are active but at different

time points during motor learning.

CHAPTER 5 Praxis and Dyspraxia ■ 131

functions, working memory, attention, and emotional regulation, all of which can infl uence our

motor performance and ability to develop practic

skills ( Koziol et al., 2014 ).

 The motor cortex provides a mechanism for

the execution of the movements that are selected

when performing a voluntary action. Neurons

in the primary motor cortex receive and encode

ongoing input about the speed, direction, and

velocity of movement ( Kandel et al., 2012 ). This

feedback comes from somatosensory input to

the thalamus as well as intracortical projections

from the primary sensory cortex. Information

from the primary motor cortex (M1), the PMC,

and the primary sensory cortex is transmitted to

the muscles for execution via the corticospinal

and corticobulbar pathways. Corticospinal fi bers

synapse in the spinal cord with lateral (lateral

corticospinal fi bers) and medial (ventral corticospinal fi bers) motor neurons, carrying signals to

muscles that will execute the motor command.

The motor system relies on a continuous fl ow of

sensory information describing the environment,

the position and orientation of the body and

extremities, and mechanical information about

muscle contraction both before and during task

performance. In addition, for volitional movement to occur, integration between and among

brain structures responsible for all levels of

motor output is required .

Neuroimaging Findings in Children

with Dyspraxia or DCD

 Although there has not been fMRI research conducted with children with dyspraxia (defi ned

using the SIPT), several recent studies have

examined neural correlates in children with DCD

(reviewed in Zwicker, Missiuna, Harris, & Boyd,

 2012 ). These studies indicated that there were

neural differences in activation in various brain

structures as well as different patterns of networks, with some areas or connections increased

and others decreased. Differences between children with DCD compared with those in a control

group were present in both motor and nonmotor tasks. Researchers looking at children with

DCD suggested possible somatosensory, proprioceptive, or internal models or body scheme

impairments in this population. This view is

remarkably similar to the hypotheses put forth

by Ayres ( 1972b ) in her early work.

HERE ’ S THE POINT

• Praxis is dependent on a complex functional

neural system including the motor cortex,

somatosensory cortex, prefrontal cortex,

premotor area, parietal lobe, basal ganglia, and

cerebellum.

Related Diagnoses

and Terminology

 The term dyspraxia is used often, but not exclusively, to describe a sensory integrative-based

praxis disorder—that is, not all children who

have dyspraxia have sensory integrative dysfunction. In fact, Ayres ( 1985 ) described some

children as having dyspraxia even though their

diffi culties were not based on poor sensory processing. To further complicate matters, a child

diagnosed with sensory integrative-based dyspraxia by an occupational therapist may be diagnosed differently by another professional as not

all disciplines evaluate sensory processing.

Related Diagnoses

 Common related diagnoses include DCD ( American Psychiatric Association, 2013 ) and DAMP

(defi cits in attention, motor control, and perception) ( Gillberg, 2003 ). Although we cannot

assume that sensory integrative-based dyspraxia,

DCD, or any other related diagnoses refer to the

same condition, the terms are all used in studies examining children ’ s motor skills, and there

are similarities in characteristics across diagnoses. Gubbay ( 1975 ) fi rst described the problems

of “clumsy children,” also referred to as children with “developmental apraxia.” He believed

that clumsy children had diffi culty performing

skilled, purposeful movements not related to

primary sensory, motor, or cognitive defi cits.

Instead, Gubbay ( 1985 ) noted that 50% had pre-,

peri-, or neonatal complications, a fi nding confi rmed by May-Benson, Koomar, and Teasdale

 ( 2009 ). Recent research has shown that preterm

birth and low birthweight are also strong risk

factors for DCD ( Zhu, Olsen, & Olesen, 2012 ;

 Zwicker, Yoon, et al., 2013 ). Similar to Gubbay ’ s

early description of clumsy children, Zwicker,

Harris, and Klassen ( 2013 ) reported a DCD

prevalence of 5% to 6% in school-aged children,

132 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

although this varied depending on the diagnostic

criteria and familiarity of professionals with the

condition. Also similar to Gubbay is the fi nding

that DCD is two to seven times more common

in boys than girls ( American Psychiatric Association, 2013 ). Piek and Coleman-Carman ( 1995 )

found that children with DCD performed signifi -

cantly poorer on a test of kinesthetic perception

and movement than matched control subjects,

which is similar to the tactile-kinesthetic impairments that Ayres ( 1972a, 1985 ) described in children with dyspraxia. In other diagnostic systems,

the International Classifi cation of Diseases and

Related Health Problems ( ICD-10; World Health

Organization [WHO], 2010 ) includes a diagnosis of “specifi c developmental disorder of motor

function” in which clumsiness is the key feature. The main feature is a serious impairment

in motor coordination development that is not

explained by intellectual delays. The draft version of ICD-11 uses the broader term of developmental motor coordination disorder, which is

marked by “severely impaired coordination . . .

in the context of otherwise normal development

of cognitive and social skills.”

 Many studies have reported an overlap

between attention defi cit-hyperactivity disorder

(ADHD) and DCD ( Kirby, Sugden, & Purcell,

 2014 ). Children who are impulsive and distractible may often fall or bump into objects and

appear clumsy because they are not paying attention to what they are doing, but may not have

motor planning problems. In Scandinavia, DAMP

is indicated when there are concomitant defi cits

of attention or hyperactivity and DCD ( Gillberg,

 2003 ). Landgren and colleagues ( 1996 ), studying

a group of 589 children who were 6 years old,

found that up to 75% of children with DAMP

could also be diagnosed with ADHD. Those with

DAMP had more defi cits in perception and motor

function, whereas impulsivity was most indicative of children with ADHD alone. BrossardRacine, Shevell, Snider, Belanger, and Majnemer

 ( 2012 ) examined a cohort of 49 children newly

diagnosed with ADHD, in which 73.5% of the

children were identifi ed with motor impairment

at baseline that persisted, even after medication,

in 55% of the sample. In a retrospective study of

309 children with ADHD, Mulligan ( 1996 ) found

that the Postural Praxis test of the SIPT was one

of the lowest scores (mean z-score –1.36) of this

group, although the SIPT praxis tests as a whole

did not differentiate children with ADHD from

children with other diagnoses.

Praxis and Autism Spectrum Disorders

 Another diagnosis that has received considerable

attention in recent years in motor performance

literature is that of ASD. Individuals with ASD

have a range of motor impairments including

diffi culty with balance, posture, gait, gross motor

skills, fi ne motor skills, and motor planning

and praxis ( Miller-Kuhaneck & Watling, 2010 ).

Although motor symptoms are not considered a

core symptom of ASD in the DSM-5 ( American

Psychiatric Association, 2013 ), these symptoms

are highly prevalent in individuals with ASD

( Hilton, Zhang, White, Klohr, & Constantino,

 2012 ; Miller-Kuhaneck & Watling, 2010 ) and

are present from infancy ( Esposito & Venuti,

 2008 ; Landa & Garrett-Mayer, 2006 ; Ozonoff

et al., 2008 ). Fournier and colleagues ( 2010 )

conducted a meta-analysis on studies examining

motor diffi culties in individuals with ASD and

found large effect sizes for a wide range of motor

behaviors across all ages. The investigators suggested that motor coordination defi cits should be

considered a cardinal feature of ASD. Mostofsky and colleagues ( 2006 ) found that children

with ASD performed more poorly than those in

a control group on multiple aspects of praxis.

Similarly, Dziuk and colleagues ( 2007 ) found

that children with ASD showed impairments

in motor planning as measured by imitation,

gesture production, and tool use, and that these

practic impairments could not be accounted for

by basic motor impairment. Because of the close

relationship between impairments in praxis and

social-communication and behavioral features of

autism, Dziuk and colleagues also suggested that

dyspraxia should be considered a core feature of

ASD. Supporting this, MacNeil and Mostofsky

 ( 2012 ) have suggested that praxis impairments,

versus general motor impairments, are unique to

autism.

 Since Ayres’ ( 1965, 1972b ) initial formulations on the role of somatosensation in the development of adequate body schema necessary for

motor planning, the SIPT has been used to assess

praxis in children with ASD in several studies.

 Roley, Mailloux, Parham, Schaaf, Lane, and

Cermak ( 2015 ) found that children with ASD

had low scores on tests of postural, oral, and

sequencing praxis, as well as low scores on the

CHAPTER 5 Praxis and Dyspraxia ■ 133

somatosensory test involving tactile discrimination and kinesthetic awareness. The mean scores

for children with ASD were more than a standard deviation below that of the control group,

suggesting defi cits in both tactile processing

and praxis. Similarly, Williams and colleagues

 ( 2006 ) found that four of six measures of tactile

and kinesthetic perception differentiated children

with high functioning autism from their typically developing peers, indicating tactile perceptual impairments. In contrast, using a different

measure of tactile perception, O’Riordan and

Passetti ( 2006 ) did not fi nd a signifi cant difference in tactile discrimination (texture discrimination; Von Frey hairs) between individuals with

and without autism. Abu-Dahab and colleagues

 ( 2013 ) reported mixed fi ndings; children and

young adults with high functioning autism did

not perform differently from those in a control

group on simple tactile tests (simple touch, sharp

dull discrimination, or fi ngertip writing), but they

did show signifi cantly lower scores on tests of

stereognosis and fi nger recognition. Given the

fi ndings of these studies, it is likely that some,

but not all, children with ASD and poor praxis

also have poor somatosensation or that some

children with ASD demonstrate adequate tactile

perception for simple tasks but show impairments on the more complex tactile perception

tasks.

 In addition to differences in somatosensory

processing and praxis functions, various neural

and genetic differences related to motor performance have been noted in children with ASD.

Functional imaging studies in individuals with

ASD have identifi ed abnormalities within brain

structures (and connections between brain areas)

related to motor performance including larger

total brain, cerebellar, and caudate nucleus

volumes with reduced corpus callosum ( Stanfi eld et al., 2008 ). Functional MRI studies also

have shown different patterns of neural activity

in individuals with ASD in areas of the brain

related to motor control and motor learning

( Verhoeven, de Cock, Lagae, & Sunaert, 2010 ;

 Zwicker, Missiuna, Harris, & Boyd, 2010 ). Thus,

there appears to be a neurobiological basis for

the motor impairments that are noted in children

with ASD. Lastly, Hilton and colleagues ( 2012 )

found a high degree of correlation between

motor impairment scores and severity of autism

in concordant identical twins in comparison with

nonidentical concordant siblings, suggesting a

genetic contribution to motor impairment.

HERE ’ S THE POINT

• Diagnostic terms related to praxis and dyspraxia

may vary by discipline.

• DCD and DAMP have overlapping symptoms.

• Research on motor and praxis skills in related

diagnoses may inform understanding of

dyspraxia.

Dyspraxia Across Ages

 Little research is available on the specifi c impact

of dyspraxia on the daily living skills of children.

Numerous studies, however, document the developmental, motor, play, and daily life diffi culties

of children with DCD. As there is much overlap

between DCD and dyspraxia, much information in the following section will be drawn from

studies on children with DCD.

Early Childhood

 Young children with dyspraxia often demonstrate

a history of early developmental challenges.

 May-Benson and colleagues ( 2009 ) examined the

early developmental characteristics of 1,000 children with sensory processing disorders. Although

not examining dyspraxia specifi cally, they found

that 43% of children with sensory processing

problems had atypical crawling development,

meaning they either crawled very early or late or

for a brief period, all potential indicators of inadequate praxis. Parents also frequently reported

that children with sensory processing problems

had diffi culties with colic, jaundice, strong preferences for certain positions, and hesitancy when

learning to navigate stairs. Additionally, parents

of children with sensory processing problems

reported that 33% of these children were not

saying words by age 12 months, 31% experienced eating problems, 32% had sleeping problems, and 45% were reported to not go through

the “terrible twos.”

 Functionally, diffi culties in praxis for very

young children are most often found in delays

or diffi culties in development of ADLs such as

self-care (e.g., fastening buttons, blowing the

nose). They may also struggle with manipulating

134 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

toys and engaging in independent play activities

(e.g., puzzles, cutting and pasting, coloring, and

playground equipment). Asonitou and colleagues

 ( 2012 ) found signifi cant relationships among

cognitive, motor, and manual dexterity skills in

5- and 6-year-old preschool children with and

without DCD. Consistent with literature on older

children with clumsiness, these preschoolers

with DCD performed more poorly than typical

peers on all motor and cognitive tasks with signifi cant differences in gross and fi ne motor skills

and developmental play skills. Engel-Yeger

(2015) further found that frequency of engagement and social interaction in play was signifi -

cantly different as children with coordination

diffi culties spent more time as onlookers, or in

transition, than typically developing peers. Children with DCD are also reported to be involved

more frequently in an aggressive incident and

show a higher frequency of negative affect than

the control children during play ( Kennedy-Behr,

Rodger, & Mickan, 2011 ).

 Dyspraxia or DCD also may be related to

a variety of social-emotional diffi culties. In a

recent questionnaire, parents of preschool children with DCD reported their children were less

independent than peers and showed less enjoyment while participating in play, leisure activities, social interaction, and educational tasks

( Bart, Jarus, Erez, & Rosenberg, 2011 ). Further,

motor ability was found to be related to anxiety,

depression, and emotional recognition in young

preschool children with DCD ( Piek, Bradbury,

Elsley, & Tate, 2008 ).

School Years

 Elementary school often marks a turning point

for children with dyspraxia. Problems become

even more obvious as the requirements of daily

events at home and school increase. Skill areas

of self-care (particularly dressing), bathing and

personal hygiene, toileting, and eating become

areas of diffi culty (Engel-Yeger, 2015). Morning

routines may turn into battles as the time

required for dressing and other self-care activities lengthens, requiring children to receive help,

be late for school, or arise very early. Furthermore, problems with completing daily routines

were found consistently across families and cultures ( Summers, Larkin, & Dewey, 2008 ). Also,

as children get older, they may be required to

participate in activities they previously avoided.

Parents in this study reported that although older

children were expected to participate more independently in the daily routine, parents provided

more structure and assistance to children with

DCD, and the parents’ expectations of independent performance were lower. Children with

DCD required consistent prompting and more

structure to complete morning tasks within the

allotted time. Children with DCD were reported

to be happier on weekends and holidays when

demands were more relaxed. Parents may

become frustrated by the child ’ s inconsistency in

performance and may attribute problems to carelessness or laziness ( Morris, 1997 ).

 Diffi culties playing ball games, getting

dressed, and participating in organized sports

are issues that are frequently cited for children

with DCD at this age ( Magalhães, Cardoso, &

Missiuna, 2011 ). Play skills such as bike riding,

skipping rope, and ball activities often are performed with diffi culty. Finally, organized sports

and physical education become increasingly

important, and children with dyspraxia often

experience diffi culty in these areas. Boys

with DCD were found to be lonelier and have

less participation in group physical activities

( Poulsen, Ziviani, Cuskelly, & Smith, 2007 ). In

a cross-cultural study, Cermak, Katz, Weintraub,

Steinhart, Raz-Silbiger, Munoz, and Lifshitz

 ( 2015 ) reported that these lower levels of participation and decreased physical activity were associated with decreased fi tness and an increased

risk of obesity in children with DCD. Overall,

studies of quality of life in children report signifi cantly poorer results in physical, psychological, and social functioning in children with

DCD compared with peers ( Zwicker, Harris, &

Klassen, 2013 ). Further, Mandich, Polatajko, and

Rodger ( 2003 ) reported that children with DCD

were often bullied, teased, and left out of peer

groups because of their motor diffi culties. These

experiences resulted in feelings of incompetency,

which negatively impacted their self-esteem.

 By the third and fourth grades, a dramatic

increase in the demand for written output occurs,

and many children experience diffi culty with

handwriting and art projects that involve cutting,

coloring, pasting, and assembling. Levine ( 1987 )

fi rst used the term developmental output failure

to describe the problem of children who could

not produce suffi cient academic work to meet

CHAPTER 5 Praxis and Dyspraxia ■ 135

expectations. Output failure may be caused by

poor visual-motor coordination, form and space

perception, motor planning or motor memory,

fi ne motor skill, organization or sequencing, or

somatosensory processing. Failure to keep up

with the amount of work required may result in

a decline in grades, motivation, and self-esteem

( Levine, 2003 ). McHale and Cermak ( 1992 )

determined from observations in second, fourth,

and sixth grade classrooms that 30% to 60% of

the school day was devoted to fi ne motor tasks.

Writing was the predominant fi ne motor task,

used for copying text, taking notes, drawing,

writing from dictation, creative writing, and completing worksheets and workbooks. Magalhães

and colleagues ( 2011 ) had identifi ed handwriting

as problematic in children with DCD. Handwriting problems may be characterized by illegibility that results from disorganized or nonuniform

letters, improper spacing, inappropriate slant, or

poor stroke quality ( Goldstand, Gevir, Cermak, &

Bissell, 2013 ). Problems in these areas are major

reasons why school-aged children are referred

for occupational therapy ( Goldstand et al., 2013 ).

As pressure mounts for handwriting to be introduced to children at younger ages, it is likely that

these diffi culties will become increasingly prevalent in our schools.

Adolescence and Adulthood

 Historically, parents were told that children with

coordination diffi culties would outgrow them;

however, several follow-up studies found motor

skill defi cits identifi ed at age 5 years persisted

into adolescence ( Cantell, Smyth, & Ahonen,

 1994 ; Cousins & Smyth, 2003 ; Losse et al.,

 1991 ), with poorer motor skills, lower academic

achievement, lower IQ scores, and more behavior problems reported in these children compared

with typical peers. Another follow-up study of

16-year-olds with DAMP found more speech and

language disorders, longer reaction times, greater

clumsiness, and higher rates of accidents resulting in bone fractures than adolescents who had

no history of DAMP ( Hellgren, Gillberg, Gillberg, & Enerkskog, 1993 ). Additionally, executive functioning, including working memory and

the ability to plan goal-directed tasks, is a key

area of dysfunction for young adults with motor

coordination diffi culties ( Kirby, Edwards, &

Sugden, 2011 ). Behaviorally, problems with

praxis may be manifested in tasks such as diffi culty managing money, planning ahead, organizing and fi nding things in their room, and time

management.

 In adulthood, dyspraxia may limit career

and avocational choices. Dysfunction in both

academic and motor realms is likely to infl uence future roles and feelings of competence,

impeding the ability to explore various available options. Adults identifi ed as very clumsy

as children had jobs requiring less manual dexterity than peers ( Knuckey & Gubbay, 1983 ),

reported lower quality of life and life satisfaction than typical peers ( Hill, Brown, & Sorgardt,

 2011 ; Kirby, Williams, Thomas, & Hill, 2013 ),

and reported several health-related problems

including high levels of anxiety and depressive

symptoms.

 Lastly, certain functional activities present

particular challenges for adolescents and adults

with DCD. Cantell and colleagues ( 1994 ) found

that adolescents with motor coordination problems had fewer hobbies than peers and were

less likely to engage in sports ( Hay & Missiuna,

 1998 ). Daily living skills may be impacted as

well, but driving presents the greatest diffi culty.

Fewer adults with DCD learn to drive compared

with those without the disorder, and those who

did drive showed diffi culties with distance estimation and parking ( Kirby et al., 2011 ), regulating speed while driving, and in coping with

distractions ( de Oliveira & Wann, 2011 ).

Behavioral and Social-Emotional

Characteristics of Children

with Dyspraxia

 Many children with dyspraxia are aware of what

they can and cannot do and avoid diffi cult situations. Shaw, Levine, and Belfer ( 1982 ) found

children with learning disabilities and poor

motor coordination had more problems with

self-esteem than did children with learning disabilities and no motor problems. They named

this phenomenon “developmental double jeopardy.” Stephenson and Chesson ( 2008 ) conducted a survey of individuals seen 6 years prior

for motor problems. Of the 35 respondents, 28

(80%) reported that motor problems persisted,

with 22 of 28 also reporting behavioral and emotional problems. Of the seven children without

persisting motor diffi culties, only one reported

136 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

social and emotional problems. Interviews with

12 parents of children from the study described

their child as having emotional problems, manifested through anger, frustration, unhappiness,

distress, depression, low self-esteem, embarrassment, and shyness. “Opting out” behaviors were

described by most mothers. Further, mood disorders frequently accompany DCD. Higher levels

of self- and parent-reported depression are seen

in children with DCD, especially when the child

is a victim of bullying ( Lingam et al., 2012 ).

Many studies have suggested higher levels of

anxiety and lower levels of self-worth ( Lingam

et al., 2012 ; Pearsall-Jones, Piek, & Rigoli, 2011 ;

 Pratt & Hill, 2011 ). Poulsen and colleagues

 ( 2007 ) found children with DCD reported higher

levels of loneliness and lower participation in all

group activities, whether structured (team sports)

or unstructured (informal outdoor play). Moreover, the extent of the child ’ s incoordination

related to his or her loneliness. In a large prospective cohort, Lingam, Golding, and Jongmans

 ( 2010 ) found that children with DCD were more

likely than their peers to have diffi culty making

and maintaining friendships. Engel-Yeger ( 2015 )

further reported that children and adolescents

with DCD have lower levels of participation

in home, school, and community settings, and

 Zwicker, Harris, and colleagues ( 2013 ) found

that lack of skill in motor performance often

leads to poor self-concept, limited social participation, and reduced quality of life.

Cognitive and Executive Function

 “As movement assumes meaning, the child

learns to motor plan or how to cortically direct

his movements” ( Ayres, 1972b , p. 170, italics

added). Although Ayres ( 1972b ) emphasized the

roles of sensory processing and body scheme in

motor planning, she also stressed the importance

of cortical and subcortical processing and indicated that the brain required a variety of information to plan actions. In regards to cortical

functions, the relationship of intelligence to dyspraxia has been the source of considerable disagreement. Historically, children with dyspraxia

were identifi ed as having normal intelligence with

the single most important diagnostic criterion for

dyspraxia being poor visual-spatial ability and

a signifi cantly lower (less than standard deviation [SD]) performance than verbal IQ score

( Gubbay, 1985 ). Similarly, Smits-Engelsman

and Hill ( 2012 ) found that only 19% of variance

in motor performance scores was explained by

IQ scores in children with varying degrees of

intellectual ability and that 26% of children with

intellectual delays had no motor defi cits. They

determined that although lower IQ scores were

more often associated with lower motor performance, there remained a considerable separation

between cognitive ability and motor skill.

 This separation is echoed in the ICD-10:2010

 (WHO, 2010), which specifi es that the disorder

of motor coordination cannot be explained by

intellectual disability. In the DSM-5 ( American

Psychiatric Association, 2013 ), it is indicated that

a diagnosis of DCD should be made only when

a child ’ s motor skills are signifi cantly lower than

his or her cognitive skills. Thus, when delays in

motor planning are consistent with intellectual

development, the child would not be diagnosed

with dyspraxia. Furthermore, care must be taken

to differentiate delays in motor skill development or execution from poor motor planning.

Children with cognitive and intellectual impairments would be considered to have dyspraxia

only when their motor defi cits are caused by

poor motor planning, not simply poor execution,

and when their motor planning is signifi cantly

poorer than their performance in other areas of

cognition.

 Executive functioning skills also may play

a role in ideation, planning, and monitoring of

motor performance. Studies examining motor

performance and executive functioning skills

in typically developing children have proposed

several underlying processes of forward planning, response inhibition, and working memory

common to motor performance; and executive skills related to planning, monitoring, and

the detection and correction of errors ( Livesey,

Keen, Rouse, & White 2006 ; Roebers & Kauer,

 2009 ). Numerous studies suggest that executive functioning skills such as working memory

(I. C. Chen, Tsai, Hsu, Ma, & Lai, 2013 ), verbal

fl uency, attention, decision-making, problemsolving, and planning are related to motor performance ( Hartman, Houwen, Scherder, &

Visscher, 2010 ). Wassenberg and colleagues

 ( 2005 ) found that overall motor performance

correlated with general cognitive skills when

tests with a motor component were included but

did not correlate when the motor-related tests

CHAPTER 5 Praxis and Dyspraxia ■ 137

were removed. They found specifi c cognitive

tests of working memory, verbal fl uency, and

visual-motor integration were related to motor

performance, independent of attention, and that

these relationships had been previously identifi ed in children with DCD, ADHD, and dyslexia

( Hamilton, 2002 ; Pitcher, Piek, & Hay, 2003 ;

 Viholainen, Ahonen, Cantell, Lyytinen, & Lyytinen, 2002 ). May-Benson ( 2005 ) examined characteristics of dyspraxic children with and without

ideational diffi culties in comparison with typical

peers. She found signifi cant differences between

all groups on measures of attention and behavior, with children with ideational problems performing worse than those in other groups. On

tests of executive planning and fl uency, children

with dyspraxia but no ideational problems performed more poorly with tasks related to fl uency

than typical peers and children with ideational

diffi culties.

HERE ’ S THE POINT

• Dyspraxia in very young children may be related

to difficulties with early developmental motor

challenges, delayed development of self-care

skills, decreased play skills, speech impairments,

and a variety of social-emotional diffi culties.

• Dyspraxia and DCD in school-aged children

may be related to poor handwriting, decreased

participation in sports, diffi culties in school, and

low self-esteem.

• Dyspraxia and DCD in adolescents and

adults may be related to diffi culties driving,

instrumental activities of daily living (IADLs),

maintaining employment, and mental health

concerns such as anxiety and depression.

The Intervention Process

 The evaluation process—observations in context,

interview, clinical observations, and the results

of standardized assessments such as the SIPT—

provides critical evidence for determining if SI

dysfunction is impairing a child ’ s everyday performance. Chapter 8 (Assessment of Sensory

Integration Functions Using the Sensory Integration and Praxis Tests), Chapter 9 (Using Clinical

Observations within the Evaluation Process), and

 Chapter 10 (Assessing Sensory Integrative Dysfunction without the SIPT) address evaluation

of sensory integrative disorders. Practitioners, in

collaboration with the children with whom they

work, caregivers, and teachers, develop a plan

for intervention. In this section, SI theory, along

with other theories of motor behavior, are used

as a framework for interventions that facilitate

the development of praxis.

Sensory Integration Principles

for Praxis Intervention

 SI is not a method by which practitioners do

something to clients. Rather, practitioners

observe how the children with whom they work

respond to sensation and cues, interact with signifi cant persons and objects, and adapt to changing environmental demands. Practitioners then

create sensory-rich environments that entice their

clients to attempt new skills, adapt in new ways,

and master appropriate challenges. Intervention

involves challenges that lead to improved organization of brain and behavior. Chapter 12 (The

Art of Therapy) and Chapter 13 (The Science

of Intervention: Creating Direct Intervention

from Theory) provide considerable detail about

using SI theory to address specifi c aspects of

practic dysfunction. The Ayres Sensory Integration © Fidelity Measure (ASIFM) is presented

in Chapter 14 (Distilling Sensory Integration

Theory for Use: Making Sense of the Complexity). There the structural and process elements

that characterize a sensory integrative treatment

session are delineated. Several key intervention

principles promoted by Ayres are especially

important when addressing praxis concerns and

are highlighted here. They include:

 1. Provision of sensory inputs for specifi c

praxis defi cits through active participation in

sensorimotor activities

 2. Child direction of activity choice

 3. Creation of the just-right challenge

 4. Facilitation of an adaptive response

 Sensory foundations for praxis have been discussed previously. This information is translated

to intervention activities to facilitate optimal

responses to intervention depending on assessment

of the individual ’ s praxis problems. For instance,

individuals who present with somatodyspraxia

will benefi t most from engaging in activities that

provide deep touch tactile and heavy work proprioception sensory inputs. These sensory inputs

138 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

facilitate development of body scheme, which is

needed for praxis. These activities are in contrast

to the vestibular-proprioceptive activities that

best facilitate individuals who present with BIS

problems. Individuals with this type of problem

benefi t from activities that provide strong movement inputs in conjunction with postural and

eye-hand coordination demands.

 Praxis intervention requires that the child initiate, plan, and execute motor actions so that the

SI intervention is child-directed. Ayres ( 1972b,

1985 ) also emphasized that an important role of

the therapist was to set up the environment so

it provided a challenge that was just right. This

creation of the just-right challenge in activities

requires much skill on the part of the therapist.

When a just-right activity is presented, the child

will want to engage in the activity and will be

successful in doing so, thus producing adaptive

responses to the environment.

 Ayres ( 1972b ) described the adaptive

response as central to praxis intervention. Adaptive responses are purposeful actions directed

toward a goal that is successfully achieved, and

the production of adaptive responses is thought

to be inherently organizing for the brain. Ayres

 ( 1972b, 1985 ) further emphasized that SI intervention was a transaction among client, task,

and environment. Although praxis enables effective transactions ( Ayres, 1985 ), the environment

guides performance by determining its parameters (E. J. Gibson, 1988 ). As the environment

changes, so must the client ’ s actions ( Franchak &

Adolph, 2014 ) (see Fig. 5-4 ).

Interventions for Motor Planning

and Motor Coordination

 In addition to treating dyspraxia from an SI

approach as described previously, several motor

behavior intervention theories have emerged that

provide useful information that may augment

and enhance traditional sensory integrative-based

interventions for the development of motor planning abilities. These theories can be divided into

three categories:

 1. Motor learning and motor control

 2. Contextual and ecological approaches

 3. Mental practice approaches

Motor Learning and Motor

Control Approaches

Motor learning refers to the acquisition or modifi cation of movement, whereas motor control

is concerned with the regulation and refi nement

of movement that has already been acquired

( Shumway-Cook & Woollacott, 2011 ). Current

motor learning theories support a model of

fl exible, changing behavior in response to the

demands of the situation, which are similar to the

adaptive response that is so integral to SI-based

intervention ( Ullsperger, Danielmeier, & Jocham,

 2014 ). Both perspectives emphasize that actions

refl ect an interaction among the person, task,

and environment. Within the person, multiple

systems (i.e., perceptual, cognitive, and motor)

interact with unique tasks in the contexts in

which they occur, requiring both feedforward and

feedback control to achieve a goal ( ShumwayCook & Woollacott, 2011 ). Within these models,

considerable emphasis has been placed on both

the environment and the individual ’ s interest for

engaging with that environment.

 Intervention for children with dyspraxia

involves creating interesting and challenging

tasks that facilitate improved motor planning

and skill acquisition. Actions are generated from

past experiences that are successful and stored as

long-term motor memories. From motor learning

and SI perspectives, repetition of motor skills is

needed for them to be stored and retrieved in a

way that supports skill development ( Brooks,

 1986 ). Traditional ideas from motor learning

indicate that blocked practice, or the repetition

of an action within a concentrated time period, is

most benefi cial for learning a new skill ( Kantak &

Winstein, 2012 ). This suggests that therapists

FIGURE 5-4 An environment that offers equipment

with many affordances can be motivating to the child

and can allow the therapist to structure a just right

challenge.

CHAPTER 5 Praxis and Dyspraxia ■ 139

using an SI approach may encourage children to

repeat a new motor planning task multiple times

within a single therapy session to best store the

motor memories from that task for long-term

retention (e.g., have a child repeat the activity of

crawling through a tunnel, climbing a ladder, and

swinging on a trapeze fi ve times).

 However, this type of learning does not necessarily increase generalizability of skills. Motor

learning is best facilitated when repetition of

activities involves variations on previously

learned tasks and occurs randomly (i.e., performance of one task followed by a different one)

across different time periods ( Schmidt & Lee,

 2013 ). Embedding a variety of movements and

tasks in novel conditions increases the adaptability of the movement ( Soderstrom & Bjork,

 2013 ). This perspective is consistent with an

SI approach to treating motor planning, which

emphasizes using similar actions while engaged

in a variety of activities (e.g., pumping swing

and throwing a beanbag or climbing a structure

and jumping in a ball pit).

 After a child has learned a skill in a therapeutic environment, it generally is necessary

to transfer that skill to situations such as home

or school. The more closely the demands of

the practice environment resemble those of the

child ’ s real-life environment, the easier the transfer of skills ( Kantak & Winstein, 2012 ). This

may be especially true for individuals who have

dyspraxia and who may have diffi culty generalizing to new situations. Because of their hypothesized diffi culty developing schemas or neuronal

models of action that can be generalized, those

with dyspraxia may have particular diffi culty

realizing gains made during intervention in their

daily lives ( Ayres, 1985 ; Brooks, 1986 ). Therapists are especially challenged to fi nd varied and

creative ways for facilitating motor learning and

motor planning, while selecting tools and materials that are likely to be encountered by the client

on a day-to-day basis.

Contextual and Ecological Approaches

 Contextual approaches to motor performance

are particularly relevant to occupational therapy

using an SI approach because active participation in meaningful occupation and the planning

and production of adaptive responses are central

to SI theory and intervention. Fidler and Fidler

 ( 1978 ) asserted that purposeful activity provided

the action–learning experience essential for

skill acquisition. Gliner ( 1985 ) emphasized the

interaction between the individual and the environment (i.e., object and task) rather than the

movement itself and suggested that the environment provided meaning and support to the person

performing the action. Similarly, King ( 1978 )

maintained that adaptive behavior was organized

best through active involvement in occupations.

She suggested that in doing purposeful tasks,

attention was directed toward the object or the

goal rather than the movement. Many of the concepts proposed by these early occupational therapists are consistent with current contextual or

ecological theory ( Rose & Christina, 2006 ).

 Contextual theories of motor behavior, known

as systems theories or ecological theories,

have examined perceptual control of action and

are focused on the idea that spatial knowledge

of the external world is derived from movement experiences associated with vision and

memory. One ecological view, known as action

systems theory, focuses on the functional specifi city and meaning of actions and emphasizes

the need to study actions within natural contexts ( Reed, 1988 ). From an SI perspective, this

means observing children performing in their

typical contexts, such as playing on the school

playground, because individuals will perform

differently in varying environments (i.e., a child

may be able to make a basket in his own home

basketball hoop but not at the school playground).

 Similar to action systems theory, dynamical systems theory challenges traditional views

that human development proceeds in an orderly

and consistent way with little variability in the

acquisition of skills. In this theory, motor behavior is described as fl uid, highly variable, and

dependent on interaction with the surrounding

world through the exploration of new contexts

( Smith & Thelen, 2003 ). Similar ideas are presented in the ecological theories of E. J. and

J. J. Gibson, whose research coupled action and

perception ( Adolph & Kretch, 2015 ). J. J. Gibson

 ( 1979 ) defi ned affordances as reciprocal relationships between a person and the environment

that enabled performance of functional tasks.

As a child acquires new motor milestones, new

opportunities are offered for perceptual discoveries. Environmental interaction, then, is the key to

facilitating and fi ne tuning perception and motor

behavior as a basis for further development. In

140 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

other words, by changing the environment, the

occupational therapist using an SI approach can

facilitate change in the child ’ s motor planning in

a functional way.

Mental Practice Approaches

 Mental practice, or imagery of an action, has

also been found to have positive infl uences on

motor learning and performance. Using mental

practice activates neural areas that are responsible for programming movements and executing a

task, regions similar to those engaged when actually performing the action ( Malouin, Jackson, &

Richards, 2013 ). Mental practice signifi cantly

increases cerebral blood fl ow to premotor and

frontal cortices as well as the SMA, all of which

play an important role in planning complex

movements performed during practic activities

( Madan & Singhal, 2012 ). Timing, force, and

organization of movements was also improved

with mental practice, apparently through activation of the cerebellum ( D’Angelo & Casali,

 2013 ), thus being a potential method of improving projected action skills. In SI intervention,

this approach may also help a child with development of ideation and motor planning skills by

consciously imagining what he or she will do

during a particular task before actually performing it, thus helping the child generate more effective motor plans.

Intervention for Ideation

 Although interventions for motor planning and

motor coordination skills are well documented,

our understanding of intervention strategies

for the ideational aspect of praxis is still in its

infancy. However, many strategies associated

with action systems and dynamical systems theories have been found clinically to be helpful

in promoting ideational skills in children with

dyspraxia. Ayres ( 1972b, 1985 ) emphasized the

importance of using a variety of equipment to

design the just-right challenge. Objects and the

environment that contains them provide guides

for action. Equipment commonly used in intervention based on SI theory provides “affordances” or qualities that promote interaction.

By increasing a child ’ s awareness of object and

action affordances, the child is able to perceive

the meaning of what to do with objects or equipment and is better able to generate ideas of ways

to act on that meaning. The child ’ s actions are

then guided, in part, by the nature of the equipment and its perceptual characteristics. Schaaf

and colleagues ( 2010 ) proposed four postulates

of change for ideation, which include bridging

the child ’ s current activity with similar previous

experiences (i.e., “remember we used the bolster

swing to climb on here last week”); providing

the child with familiar mental images related

to the child ’ s actions to promote development

of representational abilities needed for ideation

(i.e., “you are swinging on the trapeze like a

monkey”); encouraging imitation and creative

expansion of ideas (i.e., a question such as “I

wonder if you could climb up on this?”); and

exploration and increased awareness of object

affordances (i.e., “How many ways can you

think of to use this object?”). In addition to these

strategies, the use of cognitive strategies (i.e.,

questioning, bridging, providing additional information) and mental imagery, in conjunction with

facilitation of the ability to recognize and act on

affordances, can promote skills for improving

ideation for praxis.

 Recall the cases of Alyssa and Dalton

described earlier in this chapter. Next, intervention for each case is presented to demonstrate

and apply the intervention principles and strategies we have discussed for addressing childhood

dyspraxia.

PRACTICE WISDOM

The motor performance of children with dyspraxia is enhanced by gross motor play activities

rich in proprioceptive sensory input because this

input gives them a better sense of how their

bodies are moving in space. Examples of such

activities include push-and-pull games such as

tug-of-war, jumping, climbing, using swings

that bounce (have a bungee cord attached), and

playing in and with stretchy spandex. Likewise,

extracurricular activities or sports that naturally

provide a lot of proprioception, including downhill skiing, mountain biking, using a trampoline,

and horseback riding, as well as contact sports

such as wrestling and football, may be areas

where children with dyspraxia fi nd more success

than those that involve little proprioceptive

sensory input.

CHAPTER 5 Praxis and Dyspraxia ■ 141

CASE STUDY ■ INTERVENTION FOR ALYSSA

AND DALTON

 Alyssa

 Alyssa ’ s evaluation identifi ed poor processing

of tactile, vestibular, and proprioceptive sensations. She also had marked diffi culty on tests

that require motor planning and visual motor

coordination. Supplemental observations and

assessment also suggested diffi culties with generating ideas for motor actions in addition to

diffi culties planning them. It was concluded

that she had dyspraxia involving both gross and

fi ne motor planning that was related to poor

sensory processing. It was believed that motor

planning diffi culties contributed to her poor

visual-motor coordination, which affected her

handwriting, self-care skills, and play behavior

(see Fig. 5-5 ).

 In intervention, the therapist provided

Alyssa with opportunities to receive enhanced

sensation in the context of meaningful activities. Alyssa initially delighted in opportunities

to be contained in small spaces. Climbing into

a large cloth bag that was fi lled with small

plastic balls provided an opportunity for her to

plan and organize her movement in a simple

way and receive enhanced tactile input. The

bag became a washing machine as the therapist closed it up and moved it rapidly and vigorously back and forth on the mat. In doing

FIGURE 5-5 Children with somatodyspraxia may

need to practice activities, such as coloring or

handwriting, more than other children in order to

achieve success.

so, the activity provided tactile, proprioceptive, and vestibular input. Alyssa also liked to

pretend that she was a bird in a nest, created

with a large inner tube lying on the fl oor and

fi lled with pillows and beanbags; however, she

was not able to self-generate play ideas where

she actually moved her body through space.

 After Alyssa had been in occupational

therapy for several weeks, the therapist wanted

to involve her in activities that were more

demanding. For example, the therapist engaged

her in an activity of swinging on a trapeze and

letting go to land in a pile of pillows. Although

this activity, which involves planning and executing projected action sequences, was initially

diffi cult for Alyssa, the task was graded to

provide a just-right challenge. First, the therapist set up the activity so Alyssa could jump

from the top of three steps positioned next

to the pillows. Then the therapist added the

trapeze and Alyssa was able to hold herself on

the trapeze and drop into the pillows. Next, the

therapist moved the steps three feet away from

where Alyssa fi rst jumped into the pillows and

then was able to hold the trapeze and jump.

Eventually she was able to swing and drop into

the pillows. Alyssa was offered the opportunity

to try and to repeat (practice) several variations of the activity. As she accomplished the

intended goal each time, she developed action

plans that allowed her to fl exibly meet the

changing task demands.

 Dalton

 Dalton ’ s motor problems were milder with

sensory processing issues predominantly in

vestibular-proprioceptive domains. These diffi -

culties appeared to interfere with adequate postural control, coordinated use of his two body

sides, his ability to anticipate body actions,

and projecting his body through space. In addition, his distractibility and decreased attention,

which seemed to be separate from his sensory

integrative dysfunction, prevented him from

focusing and interfered with his ability to

acquire motor skills. The therapist gave Dalton

many opportunities for dynamic and intense

movement, particularly through the use of suspended equipment.

 Dalton was eager to try different swings and

found he could control the speed of the glider

to crash into towers he had built with soft foam

142 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

asked to describe what they wanted to do, they

had the opportunity to formulate a cognitive

representation of the action of climbing to the

top of the jungle gym or kicking the ball into

the net.

 For someone with BIS defi cits such as

Dalton, whose sensory integrative defi cits are

relatively mild, imagining actions (mental

practice) might be another avenue to pursue in

intervention. Before engaging in a task, Dalton

could be asked to close his eyes and imagine

that he is doing the task. This could be followed

by the actual performance of the action. Adding

the reinforcement of verbal feedback based on

his actions (e.g., saying “I like the way you

reached across your body when you picked that

up” rather than just saying “good job”) or, even

better, having Dalton identify the order and

success of events could be included. The incorporation of cognitive components (i.e., visual

direction and verbal mediation, focusing on the

activity as a whole rather than on the components, visualization of the act), together with

enhanced tactile, vestibular, proprioceptive,

and visual sensation, facilitate the development

of ideational skills and can improve planning

and production of movement. Both Alyssa and

Dalton could reap the benefi ts of combined

sensation and cognitive processes that together

enhanced their ability to plan “what to do” and

“how to do it.”

HERE ’ S THE POINT

• SI theory provides a framework to treat praxis

defi cits.

• Other theories of motor behavior offer

additional insight into interventions to facilitate

the development of praxis.

Evidence for Interventions

for Dyspraxia

 Outcomes of intervention for praxis defi cits

should refl ect changes in participation and role

performance, development of competence in

activities, improved social interactions, and improved self-esteem and self-worth. May-Benson

and Koomar ( 2010 ) completed a systematic

review of the effi cacy evidence for occupational

FIGURE 5-6 A whale swing may be a good activity

for a child with BIS as it provides vestibular and

proprioceptive inputs while coordinating the upper

and lower body.

blocks. The therapist created several challenges

to his postural reactions, and he took great pride

in his ability to stay on the swing even when

moving through wide excursions. He dubbed

the bolster swing “the bucking bronco.” As he

held onto overhead ropes, the therapist moved

the bolster in various directions with increasing

vigor, and he adapted his reactions to accommodate the increased demands. Visual-spatial

demands are also inherent in such tasks because

they involve movement in relation to objects

and the environment (see Fig. 5-6 ).

 As therapy proceeded for both children, a

broader view of dyspraxia was taken and “cognitive strategies” were used, such as visual

direction, which involves reminding clients to

look at a particular place or object, or demonstrating the activity so as to provide clients with

a visual model of how the activity is performed.

For example, when Alyssa wanted to climb to

the top of a playground jungle gym, an alternate route was indicated for her, and she was

given a cue to look up to the top of the structure. Another cognitive strategy, verbal mediation and monitoring, involves requesting that

the child verbalize what is to be done or what

has been done. Alyssa ’ s verbal skills were very

good, and it was especially helpful to her to

build on an existing strength as she engaged in

motor challenges. For Dalton, whose distractibility and short attention span were problematic,

verbal mediation helped him focus on a specifi c

goal and consider the appropriate sequence of

actions. Moreover, when both children were

CHAPTER 5 Praxis and Dyspraxia ■ 143

therapy using an SI approach with children with

problems processing and integrating sensory

information that specifi cally included children

with praxis defi cits. They found 10 of 14 studies

examining motor outcomes resulted in positive

gains in children with praxis problems, with additional improvements noted in areas of sensory

processing, behavioral regulation, academic

skills, and occupational performance. A related

systematic review by Polatajko and Cantin

 ( 2010 ) found sensorimotor interventions with

children with autism and DCD diagnoses also

resulted in positive gains in areas of neuromotor

functioning, sensory organization, and decreased

falls and suggested that sensorimotor-based interventions may be most effective in improving

body function and impairment level diffi culties.

Further, they found that performance-oriented

approaches such as direct skills teaching and

cognitive-based approaches were most effective

in improving specifi c activity performance and

participation.

 Evidence for the effectiveness of interventions

for praxis defi cits in children is limited although

additional literature exists for children with

DCD. Three meta-analyses examined interventions for children with DCD. Pless and Carlsson

 ( 2000 ) included 13 studies of motor interventions for children with DCD or equivalent conditions and concluded that the most effective motor

interventions were with children older than 5

years of age, used a specifi c skill development

approach, included a home program, and were

conducted at least three to fi ve times per week. A

meta-analysis on the use of cognitive (top-down)

approaches with children with DCD found these

children demonstrated improved skill transfer

with the use of cognitive-oriented approaches

(H. F. Chen, Tickle-Degnen, & Cermak, 2003 ).

A fi nal meta-analysis of 20 studies on motor performance interventions in children with DCD

found that intervention (task-oriented and traditional motor-training-based occupational and

physical therapy approaches) was better than no

intervention for motor defi cits with an effect size

of d = 0.56 ( Smits-Engelsman et al., 2013 ).

Summary and Conclusions

 This chapter has addressed the very complex

issues that surround praxis. Sensation and

movement are intricately intertwined in the CNS,

and a growing interest in disorders of movement has produced a rich body of work around

motor behavior. However, praxis involves more

than movement; cognitive processes also play

an important role. Intervention for practic disorders is challenging and exciting. Finally,

research suggests that both sensory-motor and

cognitive-based interventions may be effective

for children with praxis defi cits but that each

type of intervention may target different types of

outcomes.

Where Can I Find More?

 Biggs, V. (2014). Caged in chaos: A dyspraxic

guide to breaking free. London, UK: Jessica

Kingsley Publishers. A practical guide written

by a teenager with dyspraxia with down to

earth advice on a range of practical issues and

daily living skills.

 Cermak, S., & Larkin, D. (2002). Developmental

coordination disorder: A comprehensive textbook covering all aspects related to DCD and

dyspraxia. Albany, NY: Delmar Thompson

Learning.

 Dixon, G. (2017). Discover yourself: A book

for children with dyspraxia. Aimed at 7- to

10-year-olds with dyspraxia, this book has

been illustrated by children. Hitchin, Hertz

UK: Dyspraxia Foundation. http://dyspraxia

foundation.org.uk

 Kirby, A. (2017). Dyspraxia—Developmental

co-ordination disorder. Explains causes,

symptoms, and diagnostic procedures with

positive coping strategies, and how to deal

with problems faced by teenagers and adults

who have dyspraxia. Hitchin, Hertz UK: Dyspraxia Foundation. http://dyspraxiafoundation

.org.uk

 Resources available from Dyspraxia Foundation

USA: http://www.dyspraxiausa.org

 Resources available from the Spiral Foundation:

 https://thespiralfoundation.org

 References

 Abu-Dahab , S. M. N. , Holm , M. B. , Rogers , J. C. ,

 Skidmore , E. , & Minshew , N. J. ( 2013 ). Motor

and tactile-perceptual skill differences between

individuals with high-functioning autism and

typically developing individuals ages 5–21 .

Journal of Autism and Developmental Disorders ,

43 ( 10 ), 2241 – 2248 .

144 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 American Psychiatric Association . ( 2013 ). Diagnostic

and statistical manual of mental disorders

( 5th ed. ). Arlington, VA : American Psychiatric

Publishing.

 Adolph , K. , & Kretch , K. ( 2015 ). Gibson ’ s theory of

perceptual learning. International Encyclopedia

of the Social & Behavioral Sciences, 2nd Ed. , 10 ,

 127 – 134 .

 Asonitou , K. , Koutsouki , D. , Kourtessis , T. , &

 Charitou , S. ( 2012 ). Motor and cognitive

performance differences between children with

and without developmental coordination disorder

(DCD). Research in Developmental Disabilities ,

33 ( 4 ), 996 – 1005 .

 Ayres , A. J. ( 1965 ). Patterns of perceptual motor

dysfunction in children: A factor-analytic study .

Perceptual and Motor Skills , 20 , 335 – 368 .

 Ayres , A. J. ( 1966 ). Interrelations among perceptual

motor abilities in a group of normal children .

American Journal of Occupational Therapy , 20 ,

 288 – 292 .

 Ayres , A. J. ( 1971 ). Characteristics of types of

sensory integrative dysfunction. American Journal

of Occupational Therapy , 25 , 329 – 334 .

 Ayres , A. J. ( 1972a ). Improving academic scores

through sensory integration. Journal of Learning

Disabilities , 5 , 338 – 343 .

 Ayres , A. J. ( 1972b ). Sensory integration and

learning disorders . Los Angeles, CA : Western

Psychological Services.

 Ayres , A. J. ( 1977 ). Cluster analyses of measures

of sensory integration. American Journal of

Occupational Therapy , 31 , 362 – 366 .

 Ayres , A. J. ( 1985 ). Developmental dyspraxia and

adult onset apraxia . Torrance, CA : Sensory

Integration International.

 Ayres , A. J. ( 1989 ). Sensory Integration and

Praxis Tests . Los Angeles, CA : Western

Psychological.

 Ayres , A. J. , Mailloux , Z. , & Wendler , C. L. ( 1987 ).

 Developmental dyspraxia: Is it a unitary function?

Occupational Therapy Journal of Research , 7 ,

 93 – 110 .

 Bart , O. , Jarus , T. , Erez , Y. , & Rosenberg , L. ( 2011 ).

 How do young children with DCD participate and

enjoy daily activities? Research in Developmental

Disabilities , 32 ( 4 ), 1317 – 1322 .

 Beets , I. A. , Macé , M. , Meesen , R. L. , Cuypers , K. ,

 Levin , O. , & Swinnen , S. P. ( 2012 ). Active versus

passive training of a complex bimanual task: Is

prescriptive proprioceptive information suffi cient

for inducing motor learning? PloS One , 7 ( 5 ),

 e37687 .

 Blanche , E. I. ( 2010 ). Observations based on sensory

integration theory . Torrance, CA : Pediatric

Therapy Network.

 Blanche , E. I. , Bodison , S. , Chang , M. C. , &

Reinoso, G. ( 2012 ). Development of the

Comprehensive Observations of Proprioception

(COP): Validity, reliability, and factor analysis .

American Journal of Occupational Therapy ,

66 ( 6 ), 691 – 698 .

 Brooks , V. B. ( 1986 ). How does the limbic system

assist motor learning? A limbic comparator

hypothesis. Brain Behavior Evolution , 29 , 29 – 53 .

 Brossard-Racine , M. , Shevell , M. , Snider , S. ,

 Belanger , S. A. , & Majnemer , A. ( 2012 ). Motor

skills of children newly diagnosed with attention

defi cit hyperactivity disorder prior to and

following treatment with stimulant medication.

Research in Developmental Disabilities , 33 ,

 2080 – 2087 .

 Bruininks , R. H. , & Bruininks , B. D. ( 2005 ).

Bruininks-Oseretsky Test of Motor Profi ciency

(BOT-2) . San Antonio, TX : Pearson .

 Cantell , M. H. , Smyth , M. M. , & Ahonen , T. P.

( 1994 ). Clumsiness in adolescence: Educational,

motor, and social outcomes of motor delay

detected at 5 years . Adapted Physical Activity

Quarterly , 11 ( 2 ), 115 – 129 .

 Cermak , S. A. ( 2011 ). Refl ections on 25 years of

dyspraxia research. Ayres Dyspraxia Monograph,

25 Year edition . Torrance, CA : Pediatric Therapy

Network.

 Cermak , S. A. , Katz , N. , Weintraub , N. , Steinhart ,

 S. , Raz-Silbiger , S. , Munoz , M. , & Lifshitz ,

 N. ( 2015 ). Participation in physical activity,

fi tness, and risk for obesity in children with

developmental coordination disorder: A

cross-cultural study . Occupational Therapy

International , 22 ( 4 ), 163 – 173 . doi:10.1002/

oti.1393

 Chen , H. F. , Tickle-Degnen , L. , & Cermak , C.

( 2003 ). The treatment effectiveness of top-down

approaches for children with developmental

coordination disorder: A meta-analysis . Journal

of Occupational Therapy Association, R.O.C. , 21 ,

 16 – 28 .

 Chen , I. C. , Tsai , P. L. , Hsu , Y. W. , Ma , H. I. , & Lai ,

 H. A. ( 2013 ). Everyday memory in children with

developmental coordination disorder . Research

in Developmental Disabilities , 34 ( 1 ), 687 – 694 .

 doi:10.1016/j.ridd.2012.09.012

 Chen , J. L. , Penhune , V. B. , & Zatorre , R. J. ( 2008 ).

 Moving on time: Brain network for auditorymotor synchronization is modulated by rhythm

complexity and musical training. Journal of

Cognitive Neuroscience , 20 ( 2 ), 226 – 239 .

 Chen , J. L. , Rae , C. , & Watkins , K. E. ( 2012 ).

 Learning to play a melody: An fMRI study

examining the formation of auditory-motor

associations. Neuroimage , 59 ( 2 ), 1200 – 1208 .

 Cousins , M. , & Smyth , M. M. ( 2003 ). Developmental

coordination impairments in adulthood . Human

Movement Science , 22 ( 4 ), 433 – 459 . doi:10.1016/

j.humov.2003.09.003

 D’Angelo , E. , & Casali , S. ( 2013 ). Seeking a

unifi ed framework for cerebellar function and

dysfunction: From circuit operations to cognition.

Frontiers in Neural Circuits , 6 ( 116 ), 1 – 23 .

 Daprati , E. , Sirigu , A. , & Nico , D. ( 2010 ). Body and

movement: Consciousness in the parietal lobes .

Neuropsychologia , 48 ( 3 ), 756 – 762 . doi:10.1016/

j.neuropsychologia.2009.10.008

CHAPTER 5 Praxis and Dyspraxia ■ 145

 de Oliveira , R. F. , & Wann , J. P. ( 2011 ). Driving

skills of young adults with developmental

coordination disorder: Regulating speed

and coping with distraction. Research in

Developmental Disabilities , 32 ( 4 ), 1301 – 1308 .

 Dijkerman , H. C. , & de Haan , E. H. ( 2007 ).

 Somatosensory processes subserving perception

and action. Behavior and Brain Science , 30 ( 2 ),

 189 – 201 . doi: 10.1017/S0140525X07001392

 Dionne , J. K. , Legon , W. , & Staines , W. R. ( 2013 ).

 Crossmodal infl uences on early somatosensory

processing: Interaction of vision, touch, and taskrelevance. Experimental Brain Research , 226 ( 4 ),

 503 – 512 .

 Dunn , W. ( 2013 ). The Sensory Profi le—Second

ed. Examiner ’ s manual . San Antonio, TX : The

Psychological Corporation.

 Dziuk , M. A. , Gidley Larson , J. C. , Apostu ,

 A. , Mahone , E. M. , Denckla , M. B. , &

 Mostofsky , S. H. ( 2007 ). Dyspraxia in

autism: Association with motor, social, and

communicative defi cits . Developmental Medicine

and Child Neurology , 49 ( 10 ), 734 – 739 .

 doi:10.1111/j.1469-8749.2007.00734.x

 Engel-Yeger , B. ( 2015 ). Developmental coordination

and participation. In J. Cairney ( Ed .),

Developmental coordination disorder and its

consequences . Toronto : University of Toronto

Press.

 Esposito , G. , & Venuti , P. ( 2008 ). Analysis of

toddlers’ gait after six months of independent

walking to identify autism: A preliminary study 1 .

Perceptual and Motor Skills , 106 ( 1 ), 259 – 269 .

 Exner , C. E. ( 1992 ). In-hand manipulation skills .

In J. Case-Smith & C. Pehoski ( Eds .),

Development of hand skills in the child .

Rockville, MD : American Occupational Therapy

Association.

 Fidler , G. S. , & Fidler , J. W. ( 1978 ). Doing

and becoming: Purposeful action and selfactualization. American Journal of Occupational

Therapy , 32 , 305 – 310 .

 Foundas , A. L. ( 2013 ). Apraxia: Neural mechanisms

and functional recovery . Handbook of Clinical

Neurology , 110 , 335 – 345 .

 Fournier , K. A. , Hass , C. J. , Naik , S. K. , Lodha , N. , &

 Cauraugh , J. H. ( 2010 ). Motor coordination in

autism spectrum disorders: A synthesis and metaanalysis. Journal of Autism and Developmental

Disorders , 40 ( 10 ), 1227 – 1240 . doi:10.1007/

s10803-010-0981-3

 Franchak , J. , & Adolph , K. ( 2014 ). Affordances

as probabilistic functions: Implications for

development, perception, and decisions for action.

Ecological Psychology , 26 , 109 – 124 .

 Fuster , J. M. ( 2008 ). The prefrontal cortex ( 4th ed. ).

 Amsterdam, Netherlands : Elsevier .

 Gee , B. M. , Devine , N. , Werth , A. , & Phan , V.

( 2013 ). Paediatric occupational therapists’ use

of sound - based interventions: A survey study .

Occupational Therapy International , 20 ( 3 ),

 155 – 162 .

 Gentsch , A. , Weber , A. , Synofzik , M. , Vosgerau ,

 G. , & Schütz-Bosbach , S. ( 2016 ). Towards a

common framework of grounded action cognition:

Relating motor control, perception and cognition.

Cognition , 146 , 81 – 89 .

 Gibson , E. J. ( 1988 ). Exploratory behavior in the

development of perceiving, acting and the

acquiring of knowledge. Annual Review of

Psychology , 39 , 1 – 41 .

 Gibson , J. J. ( 1979 ). The ecological approach to

visual perception . Boston, MA : Houghton-Miffl in .

 Gillberg , C. ( 2003 ). Defi cits in attention, motor

control, and perception: A brief review . Archives

of Child Development , 88 , 904 – 910 .

 Gliner , J. A. ( 1985 ). Purposeful activity in motor

learning theory: An event approach to motor skill

acquisition. American Journal of Occupational

Therapy , 39 , 28 – 34 .

 Goldstand , S. , Gevir , D. , Cermak , S. , & Bissell ,

 J. ( 2013 ). Here ’ s how I write: A child ’ s self

assessment and handwriting tool . Framingham,

MA : Therapro .

 Gubbay , S. S. ( 1975 ). The clumsy child . New York,

NY : W. B. Saunders .

 Gubbay , S. S. ( 1985 ). Clumsiness . In P. J. Vinken ,

G. W. Bruyn , & H. L. Klawans ( Eds .), Handbook

of clinical neurology (Rev. series) . New York, NY :

 Elsevier Science .

 Hamilton , S. S. ( 2002 ). Evaluation of clumsiness

in children. American Family Physician , 66 ,

 1435 – 1440 .

 Hardwick , R. M. , Rottschy , C. , Miall , R. C. , &

 Eickhoff , S. B. ( 2013 ). A quantitative meta

analysis and review of motor learning in the

human brain . NeuroImage , 67 , 283 – 297 .

 Harrington , D. L. , Rao , S. M. , Haaland , K. Y. ,

 Bobholz , J. A. , Mayer , A. B. , & Binderix , J. R.

( 2000 ). Ideomotor apraxia and cerebral dominance

for motor control . Cognitive Brain Research , 3 ,

 95 – 100 .

 Hartman , E. , Houwen , S. , Scherder , E. , & Visscher ,

 C. ( 2010 ). On the relationship between motor

performance and executive functioning in

children with intellectual disabilities. Journal of

Intellectual Disability Research , 54 ( 5 ), 468 – 477 .

 Hay , J. , & Missiuna , C. ( 1998 ). Motor profi ciency

in children reporting low levels of participation

in physical activity . Canadian Journal of

Occupational Therapy , 65 ( 2 ), 64 – 71 .

 Hellgren , L. , Gillberg , C. , Gillberg , I. C. , &

 Enerkskog , I. ( 1993 ). Children with defi cits in

attention, motor control, and perception (DAMP)

almost grown up: General health at 16 years.

Developmental Medicine and Child Neurology ,

35 , 881 – 892 .

 Henderson , S. , Sugden , D. , & Barnett , A. ( 2007 ).

Movement Assessment Battery for Children—

Second Edition (MABC-2) . San Antonio, TX :

 Pearson .

 Hill , E. L. , Brown , D. , & Sorgardt , K. S. ( 2011 ).

 A preliminary investigation of quality of life

satisfaction reports in emerging adults with and

146 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

without developmental coordination disorder .

Journal of Adult Development , 18 ( 3 ), 130 – 134 .

 Hilton , C. L. , Zhang , Y. , White , M. R. , Klohr ,

C. L. , & Constantino , J. ( 2012 ). Motor impairment

in sibling pairs concordant and discordant for

autism spectrum disorders. Autism , 16 , 430 – 441 .

 doi:10.1177/1362361311423018

 It ō , M. ( 2012 ). Cerebellum: The brain for an implicit

self . Upper Saddle River, NJ : FT Press .

 Ivey , C. K. , Lane , S. J. , & May-Benson , T. A.

( 2014 ). Interrater reliability and developmental

norms in preschoolers for the Motor Planning

Maze Assessment (MPMA). American Journal of

Occupational Therapy , 68 ( 5 ), 539 – 545 .

 Jeannerod , M. , & Decety , J. ( 1995 ). Mental motor

imagery: A window into the representational

stages of action. Current Opinion in Neurobiology ,

5 ( 6 ), 727 – 732 .

 Kandel , E. R. , Schwartz , J. H. , Jessell , T. M. ,

 Siegelbaum , S. A. , & Hudspeth , A. ( 2012 ).

Principles of neural science ( 5th ed. ). New York,

NY : McGraw-Hill Professional .

 Kantak , S. S. , & Winstein , C. J. ( 2012 ). Learningperformance distinction and memory processes for

motor skills: A focused review and perspective .

Behavioral Brain Research , 228 ( 1 ), 219 – 231 .

 Kawar , M. ( 2005 ). A sensory integration context for

vision . In M. Gentile ( Ed .), Functional visual

behavior in children ( 2nd ed. , pp . 87 – 144 ).

 Bethesda, MD : American Occupational Therapy

Association Press.

 Kennedy-Behr , A. , Rodger , S. , & Mickan , S. ( 2011 ).

 Physical and social play of preschool children

with and without coordination diffi culties:

Preliminary fi ndings . British Journal of

Occupational Therapy , 74 ( 7 ), 348 – 354 .

 Kiernan , J. , & Rajakumar , R. ( 2013 ). Barr ’ s the

human nervous system: An anatomical viewpoint .

 Philadelphia, PA : Lippincott Williams & Wilkins .

 King , B. R. , Kagerer , F. A. , Harring , J. R. ,

Contreras-Vidal , J. L. , & Clark , J. E. ( 2011 ).

 Multisensory adaptation of spatial-to-motor

transformations in children with developmental

coordination disorder . Experimental Brain

Research , 212 ( 2 ), 257 – 265 .

 King , L. J. ( 1978 ). Toward a science of adaptive

responses. American Journal of Occupational

Therapy , 32 , 429 – 437 .

 Kirby , A. , Edwards , L. , & Sugden , D. ( 2011 ).

 Emerging adulthood in developmental

co-ordination disorder: Parent and young

adult perspectives. Research in Developmental

Disabilities , 32 ( 4 ), 1351 – 1360 . doi:10.1016/

j.ridd.2011.01.041

 Kirby , A. , Sugden , D. , & Purcell , C. ( 2014 ).

 Diagnosing developmental coordination disorders

(Review). Archives of Diseases of Childhood , 99 ,

 292 – 296 .

 Kirby , A. , Williams , N. , Thomas , M. , & Hill ,

E. L. ( 2013 ). Self-reported mood, general health,

wellbeing and employment status in adults with

suspected DCD. Research in Developmental

Disabilities , 34 ( 4 ), 1357 – 1364 . doi:10.1016/

j.ridd.2013.01.003

 Knuckey , N. , & Gubbay , S. S. ( 1983 ). Clumsy

children: A prognostic study . Australian Pediatric

Journal , 19 , 9 – 13 .

 Koziol , L. F. , Budding , D. , Andreasen , N. , D ’ Arrigo ,

 S. , Bulgheroni , S. , Imamizu , H. , . . . Yamazaki , T.

( 2014 ). Consensus paper: The cerebellum ’ s role

in movement and cognition. Cerebellum , 13 ( 1 ),

151 – 177 . doi:10.1007/s12311-013-0511-x

 Lai , J. S. , Fisher , A. , Magalhães , L. , & Bundy ,

 A. ( 1996 ). Construct validity of the Sensory

Integration and Praxis Tests . Occupational

Therapy Journal of Research , 16 , 75 – 97 .

 Landa , R. , & Garrett-Mayer , E. ( 2006 ). Development

in infants with autism spectrum disorders:

A prospective study . Journal of Child

Psychology and Psychiatry , 47 ( 6 ), 629 – 638 .

 doi:10.1111/j.1469-7610.2006.01531.x

 Landgren , M. , Pettersen , R. , Kjellman , B. , &

 Gillberg , C. ( 1996 ). ADHD, DAMP and other

neurodevelopmental disorders in 6-year-old

children: Epidemiology and co-morbidity .

Developmental Medicine and Child Neurology ,

38 , 891 – 906 .

 Lane , S. J. , Ivey , C. K. , & May-Benson , T. A. ( 2014 ).

 Test of Ideational Praxis (TIP): Preliminary

fi ndings and interrater and test–retest reliability

with preschoolers. American Journal of

Occupational Therapy , 68 ( 5 ), 555 – 561 .

 Levine , M. D. ( 1987 ). Motor implementation . In

M. D. Levine ( Ed .), Developmental variation and

learning disorders ( pp . 208 – 239 ). Cambridge,

MA : Educators Publishing Service .

 Levine , M. D. ( 2003 ). The myth of laziness . New

York, NY : Simon and Schuster .

 Lin , C. K. , Wu , H. M. , Lin , C. H. , Wu , Y. Y. , Wu ,

 P. F. , Kuo , B. C. , & Yeung , K. T. ( 2012 ). A small

sample test of the factor structure of postural

movement and bilateral motor integration using

structural equation modeling. Perceptual and

Motor Skills , 115 ( 2 ), 544 – 557 .

 Lingam , R. , Golding , J. , & Jongmans , M. J.

( 2010 ). The association between developmental

coordination disorder and other developmental

traits. Pediatrics , 126 ( 1 ), e1109 – e1118 .

 Lingam , R. , Jongmans , M. J. , Ellis , M. , Hunt ,

 L. P. , Golding , J. , & Emond , A. ( 2012 ). Mental

health diffi culties in children with developmental

coordination disorder . Pediatrics , 129 ( 4 ), e882 –

 e891 . doi:10.1542/peds.2011-1556

 Livesey , D. , Keen , J. , Rouse , J. , & White , F. ( 2006 ).

 The relationship between measures of executive

function, motor performance and externalising

behaviour in 5- and 6-year-old children. Human

Movement Science , 25 ( 1 ), 50 – 64 . doi:10.1016/

j.humov.2005.10.008

 Lohse , K. R. , Wadden , K. , Boyd , L. A. , & Hodges ,

N. J. ( 2014 ). Motor skill acquisition across

short and long time scales: A meta-analysis

of neuroimaging data . Neuropsychologia , 59 ,

 130 – 141 .

CHAPTER 5 Praxis and Dyspraxia ■ 147

 Lopez , C. , Schreyer , H. M. , Preuss , N. , & Mast , F. W.

( 2012 ). Vestibular stimulation modifi es the body

schema. Neuropsychologia , 50 ( 8 ), 1830 – 1837 .

 Losse , A. , Henderson , S. E. , Elliman , D. , Hall , D. ,

 Knight , E. , & Jongmans , M. ( 1991 ). Clumsiness

in children—do they grow out of it? A 10-year

follow-up study . Developmental Medicine and

Child Neurology , 33 ( 1 ), 55 – 68 .

 Lundy-Ekman , L. ( 2013 ). Neuroscience fundamentals

for rehabilitation ( 4th ed. ). Philadelphia, PA : W.B.

Saunders.

 Luria , A. R. ( 1963 ). Restoration of function after

brain injury . New York NY : Pergamon .

 Luria , A. R. ( 1980 ). Higher cortical functions in man .

 New York, NY : Basic .

 MacNeil , L. K. , & Mostofsky , S. H. ( 2012 ).

 Specifi city of dyspraxia in children with autism .

Neuropsychology , 26 ( 2 ), 165 – 171 . doi:10.1037/

a0026955

 Madan , C. R. , & Singhal , A. ( 2012 ). Using actions to

enhance memory: Effects of enactment, gestures,

and exercise on human memory . Frontiers in

Psychology , 3 ( 507 ), 1 – 4 .

 Magalhães , L. C. , Cardoso , A. A. , & Missiuna , C.

( 2011 ). Activities and participation in children

with developmental coordination disorder: A

systematic review . Research in Developmental

Disabilities , 32 ( 4 ), 1309 – 1316 . doi:10.1016/

j.ridd.2011.01.029

 Mailloux , Z. , Mulligan , S. , Roley , S. S. , Blanche ,

 E. , Cermak , S. , Coleman , G. G. , . . . Lane , C. J.

( 2011 ). Verifi cation and clarifi cation of patterns of

sensory integrative dysfunction. American Journal

of Occupational Therapy , 65 ( 2 ), 143 – 151 .

 Majernik , J. , Molcan , M. , & Majernikova , Z.

( 2010, January ). Evaluation of posture stability

in patients with vestibular diseases. In Applied

Machine Intelligence and Informatics (SAMI),

2010 IEEE 8th International Symposium on

Applied Machine Intelligence and Informatics

( pp . 271 – 274 ). IEEE .

 Malkani , R. , & Zadikoff , C. ( 2011 ). The apraxias in

movement disorders. In N. G. Gálvez-Jiménez

& P. Tuite ( Eds .), Uncommon causes of

movement disorders ( pp . 35 – 45 ). Cambridge, UK :

 Cambridge University Press .

 Malouin , F. , Jackson , P. L. , & Richards , C. L.

( 2013 ). Towards the integration of mental practice

in rehabilitation programs. A critical review .

Frontiers of Human Neuroscience , 7 , 576 .

 doi:10.3389/fnhum.2013.00576

 Mandich , A. D. , Polatajko , H. J. , & Rodger ,

 S. ( 2003 ). Rites of passage: Understanding

participation of children with developmental

coordination disorder . Human Movement Science ,

22 ( 4-5 ), 583 – 95 . doi:S0167945703000733

 May-Benson , T. A. ( 2000 ). Preliminary validity

evidence for the Test of Ideational Praxis .

 Unpublished manuscript .

 May-Benson , T. ( 2001 ). A theoretical model of

ideation. In E. Blanche , R. Schaaf , & S. Smith

 Roley ( Eds .), Understanding the nature of sensory

integration with diverse populations . San Antonio,

TX : Therapy Skill Builders .

 May-Benson , T. A. ( 2005 ). Examining ideational

abilities in children with dyspraxia. Doctoral

dissertation. Boston University. Ann Arbor, MI:

ProQuest.

 May-Benson , T. A. , & Cermak , S. A. ( 2007 ).

 Development of an assessment for ideational

praxis. American Journal of Occupational

Therapy , 61 ( 2 ), 148 – 153 .

 May-Benson , T. A. , & Koomar , J. A. ( 2010 ).

 Systematic review of the research evidence

examining the effectiveness of interventions

using a sensory integrative approach for children .

American Journal of Occupational Therapy ,

64 ( 3 ), 403 – 414 .

 May-Benson , T. A. , Koomar , J. A. , & Teasdale , A.

( 2009 ). Incidence of pre-, peri-, and post-natal

birth and developmental problems of children

with sensory processing disorder and children

with autism spectrum disorder . Frontiers of

Integrative Neuroscience , 3 ( 31 ), doi:10.3389/

neuro.07.031.2009

 McHale , K. , & Cermak , S. ( 1992 ). Fine motor

activities in elementary school: Preliminary

fi ndings and provisional implications for children

with fi ne motor problems . American Journal of

Occupational Therapy , 46 , 898 – 903 .

 Medina , J. , & Coslett , H. B. ( 2010 ). From maps

to form to space: Touch and the body schema .

Neuropsychologia , 48 ( 3 ), 645 – 654 . doi:10.1016/

j.neuropsychologia.2009.08.017

 Miller , L. J. , & Schoen , S. A. ( 2012 ). The Sensory

Processing Scales Inventory (SenSI) .

Greenwood Village, CO : Developmental

Technologies .

 Miller-Kuhaneck , H. , & Watling , R. ( 2010 ). Autism:

A comprehensive occupational therapy approach

( 3rd ed. ). Bethesda, MD : AOTA Press .

 Morris , M. K. ( 1997 ). Developmental dyspraxia . In

 L. J. G. Rothi & K. M. Heilman ( Eds .), Apraxia:

The neuropsychology of action ( pp . 245 – 268 ).

 Hove, England : Psychology Press .

 Mostofsky , S. H. , Dubey , P. , Jerath , V. K. ,

 Jansiewica , E. M. , Goldberg , M. , & Denckla ,

 M. B. ( 2006 ). Developmental dyspraxia is not

limited to imitation in children with autism

spectrum disorder . Journal of the International

Neuropsychological Society , 12 , 314 – 326 .

 doi:10.1017/S1355617706060437

 Mulligan , S. ( 1996 ). An analysis of score patterns of

children with attention disorders on the Sensory

Integration and Praxis Tests . American Journal of

Occupational Therapy , 50 ( 8 ), 647 – 654 .

 Mulligan , S. ( 1998 ). Patterns of sensory integration

dysfunction: A confi rmatory factor analysis .

American Journal of Occupational Therapy , 52 ,

 819 – 828 .

 Nelson , A. B. , & Kreitzer , A. C. ( 2014 ).

Reassessing models of basal ganglia function and

dysfunction. Annual Review of Neuroscience ,

37 , 117 .

148 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 O’Riordan , M. , & Passetti , F. ( 2006 ). Discrimination

in autism within different sensory modalities.

Journal of Autism and Developmental Disorders ,

36 ( 5 ), 665 – 675 . doi:10.1007/s10803-006-0106-1

 Ozonoff , S. , Young , G. S. , Goldring , S. , Greiss-Hess ,

 L. , Herrera , A. M. , Steele , J. , . . . Rogers , S. J.

( 2008 ). Gross motor development, movement

abnormalities, and early identifi cation of

autism. Journal of Autism and Developmental

Disorders , 38 ( 4 ), 644 – 656 . doi:10.1007/s10803

-007-0430-0

 Parham , L. , Ecker , C. , Miller Kuhaneck , H. , Henry ,

 D. , & Glennon , T. ( 2007 ). Sensory Processing

Measure (SPM) manual . Los Angeles, CA :

 Western Psychological Services .

 Pearsall-Jones , J. G. , Piek , J. P. , & Rigoli , D. ( 2011 ).

 Motor disorder and anxious and depressive

symptomatology: A monozygotic co-twin control

approach. Research in Developmental Disabilities ,

32 ( 1 ), 1245 – 1252 .

 Peterka , R. J. , Statler , K. D. , Wrisley , D. M. , &

 Horak , F. B. ( 2011 ). Postural compensation for

unilateral vestibular loss . Frontiers in Neurology ,

2 , 57 . doi:10.3389/fneur.2011.00057

 Piek , J. P. , Bradbury , G. S. , Elsley , S. C. , & Tate ,

 L. ( 2008 ). Motor coordination and social–

emotional behaviour in preschool - aged children .

International Journal of Disability, Development

and Education , 55 ( 2 ), 143 – 151 .

 Piek , J. P. , & Coleman-Carman , R. ( 1995 ).

 Kinesthetic sensitivity and motor performance in

children with developmental coordination disorder .

Developmental Medicine and Child Neurology ,

37 , 976 – 984 .

 Pitcher , T. M. , Piek , J. P. , & Hay , D. A. ( 2003 ). Fine

and gross motor ability in males with ADHD.

Developmental Medicine & Child Neurology ,

45 ( 8 ), 525 – 535 .

 Pless , M. , & Carlsson , M. ( 2000 ). Effects of motor

skill intervention on developmental coordination

disorder: A meta-analysis . Adapted Physical

Activity Quarterly , 17 , 381 – 401 .

 Plotnik , M. , Shema , S. , Dorfman , M. , Gazit , E. ,

 Brozgol , M. , Giladi , N. , & Hausdorff , J. M.

( 2014 ). A motor learning-based intervention

to ameliorate freezing of gait in subjects with

Parkinson ’ s disease . Journal of Neurology , 261 ( 7 ),

 1329 – 1339 .

 Polatajko , H. J. , & Cantin , N. ( 2010 ). Exploring

the effectiveness of occupational therapy

interventions, other than the sensory integration

approach, with children and adolescents

experiencing diffi culty processing and integrating

sensory information. American Journal of

Occupational Therapy , 64 ( 3 ), 415 – 429 .

 Poulsen , A. A. , Ziviani , J. M. , Cuskelly , M. , & Smith ,

 R. ( 2007 ). Boys with developmental coordination

disorder: Loneliness and team sports participation.

American Journal of Occupational Therapy , 61 ,

 451 – 462 .

 Pratt , M. L. , & Hill , E. L. ( 2011 ). Anxiety profi les

in children with and without developmental

coordination disorder . Research in Developmental

Disabilities , 32 ( 1 ), 1253 – 1259 .

 Purves , D. , Augustine , G. J. , Fitzpatrick , D. , Hall ,

 W. C. , LaMantia , A.-S. , & White , L. E. ( 2012 ).

Neuroscience ( 5th ed. ). Sunderland, MA : Sinauer

Associates, Inc .

 Reed , E. ( 1988 ). From the motor theory of perception

to the perceptual control of action. In E. S. Reed

( Ed .), James J. Gibson and the psychology of

perception (pp. 67 – 88 ). New Haven, CT : Yale

University .

 Rine , R. M. ( 2009 ). Growing evidence for balance

and vestibular problems in children. Audiological

Medicine , 7 ( 3 ), 138 – 142 .

 Rine , R. M. , & Wiener-Vacher , S. ( 2013 ). Evaluation

and treatment of vestibular dysfunction in

children. NeuroRehabilitation , 32 ( 3 ), 507 – 518 .

 Roebers , C. M. , & Kauer , M. ( 2009 ). Motor and

cognitive control in a normative sample of 7-yearolds . Developmental Science , 12 ( 1 ), 175 – 181 .

 doi:10.1111/j.1467-7687.2008.00755.x

 Roley , S. S. , Mailloux , Z. , Parham , D. , Schaaf ,

 R. , Lane , C. J. , & Cermak , S. ( 2015 ). Sensory

Integration and Praxis patterns in children with

autism . American Journal of Occupational

Therapy , 69 . doi:10.5014/ajot.2015.012476

 Rosblad , B. ( 2002 ). Visual perception in children

with developmental coordination disorder . In S.

 Cermak & D. Larkin ( Eds .), Developmental motor

coordination disorder ( pp . 104 – 116 ). New York,

NY : Delmar Thomson .

 Rose , D. J. , & Christina , R. W. ( 2006 ). A multilevel

approach to the study of motor control and

learning ( 2nd ed. ). San Francisco, CA : Pearson/

Benjamin Cummings.

 Roy , E. A. , Black , S. E. , Stamenova , V. , Hebert , D. ,

& Gonzalez , D. ( 2014 ). Limb apraxia: Types,

neural correlates, and implications for clinical

assessment and function in daily living . In

T. A. Schweizer & R. L. Macdonald ( Eds .), The

behavioral consequences of stroke ( pp . 51 – 69 ).

 New York, NY : Springer .

 Rutherford , M. D. , & Rogers , S. J. ( 2003 ). Cognitive

underpinnings of pretend play in autism . Journal

of Autism and Developmental Disorders , 33 ( 3 ),

 289 – 302 .

 Schaaf , R. C. , Schoen , S. A. , Smith Roley , S. , Lane ,

 S. J. , Koomar , J. , & May-Benson , T. A. ( 2010 ). A

frame of reference for sensory integration. In P.

 Kramer & J. Hinojosa ( Eds .), Frame of reference

for pediatric occupational therapy ( 3rd ed .,

 pp . 99 – 186 ). Philadelphia, PA : Lippincott

Williams & Wilkins .

 Schmahmann , J. D. , Anderson , C. M. , Newton , N. , &

 Ellis , R. ( 2002 ). The function of the cerebellum

in cognition, affect and consciousness: Empirical

support for the embodied mind . Consciousness &

Emotion , 2 ( 2 ), 273 – 309 .

 Schmidt , R. , & Lee , T. ( 2013 ). Motor learning and

performance, 5E with web study guide: From

principles to application . Champaign, IL : Human

Kinetics Pub Inc .

CHAPTER 5 Praxis and Dyspraxia ■ 149

 Serino , A. , & Haggard , P. ( 2010 ). Touch and the

body . Neuroscience Biobehavioral Review , 34 ( 2 ),

 224 – 236 . doi:10.1016/j.neubiorev.2009.04.004

 Shaw , L. , Levine , M. D. , & Belfer , M. ( 1982 ).

 Developmental double jeopardy: A study of

clumsiness and self esteem in children with

learning problems. Journal of Developmental and

Behavioral Pediatrics , 3 ( 4 ), 191 – 196 .

 Shumway-Cook , A. , & Woollacott , M. ( 2011 ).

Motor control: Translating research into clinical

practice ( 4th ed. ). Baltimore, MD : Williams &

Wilkins .

 Smith , L. B. , & Thelen , E. ( 2003 ). Development as

a dynamic system . Trends in Cognitive Sciences ,

7 ( 8 ), 343 – 348 .

 Smits-Engelsman , B. C. , Blank , R. , van der Kaay ,

 A. C. , Mosterd - van der Meijs , R. , Vlugt - van

den Brand , E. , Polatajko , H. J. , & Wilson , P.H.

( 2013 ). Effi cacy of interventions to improve motor

performance in children with developmental

coordination disorder: A combined systematic

review and meta-analysis. Developmental

Medicine and Child Neurology , 55 ( 3 ), 229 – 237 .

 doi:10.1111/dmcn.12008

 Smits-Engelsman , B. C. , & Hill , E. L. ( 2012 ). The

relationship between motor coordination and

intelligence across the IQ range. Pediatrics ,

130 ( 4 ), e950 – e956 . doi:10.1542/peds.2011-3712

 Sober , S. J. , & Sabes , P. N. ( 2005 ). Flexible strategies

for Sensory Integration during motor planning.

Nature Neuroscience , 8 ( 4 ), 490 – 497 .

 Soderstrom , N. , & Bjork , R. ( 2013 ). Learning

versus performance. Oxford Bibliographies in

Psychology . doi:10.1093/obo/978-199828340

-0081

 Stanfi eld , A. C. , McIntosh , A. M. , Spencer , M. D. ,

 Philip , R. , Gaur , S. , & Lawrie , S. M. ( 2008 ).

 Towards a neuroanatomy of autism: A systematic

review and meta-analysis of structural magnetic

resonance imaging studies. European Psychiatry ,

23 ( 4 ), 289 – 299 .

 Steinman , K. J. , Mostofsky , S. H. , & Denckla ,

 M. B. ( 2010 ). Toward a narrower, more

pragmatic view of developmental dyspraxia.

Journal of Child Neurology , 25 ( 1 ), 71 – 81 .

 doi:10.1177/0883073809342591

 Stephenson , E. A. , & Chesson , R. A. ( 2008 ). ‘ Always

the guiding hand’: Parents’ accounts of the longterm implications of developmental co-ordination

disorder for their children and families. Child

Care Health Development , 34 ( 3 ), 335 – 343 .

 doi:10.1111/j.1365-2214.2007.00805.x

 Sugden , D. , Kirby , A. , & Dunford , C. ( 2008 ).

 Issues surrounding children with developmental

coordination disorder . International Journal of

Disability, Development and Education , 55 ( 2 ),

 173 – 187 .

 Sugden , D. , & Keogh , J. ( 1990 ). Problems in

movement skill development . Columbia, South

Carolina: University of South Carolina Press .

 Summers , J. , Larkin , D. , & Dewey , D. ( 2008 ).

 Activities of daily living in children with

developmental coordination disorder: Dressing,

personal hygiene, and eating skills . Human

Movement Science , 27 ( 2 ), 215 – 229 .

 Tracy , J. , Flanders , A. , Madi , S. , Laskas , J. , Stoddard ,

 E. , Pyrros , A. , . . . DelVecchio , N. ( 2003 ).

Regional brain activation associated with

different performance patterns during learning of

a complex motor skill . Cerebral Cortex , 13 ( 9 ),

 904 – 910 .

 Ullsperger , M. , Danielmeier , C. , & Jocham , G.

( 2014 ). Neurophysiology of performance

monitoring and adaptive behavior . Physiological

Reviews , 94 ( 1 ), 35 – 79 .

 Vaivre-Douret , L. ( 2014 ). Developmental

coordination disorders: State of art .

Neurophysiologie Clinique/Clinical

Neurophysiology , 44 ( 1 ), 13 – 23 .

 Verhoeven , J. S. , de Cock , P. , Lagae , L. , &

 Sunaert , S. ( 2010 ). Neuroimaging of autism .

Neuroradiology , 52 ( 1 ), 3 – 14 . doi:10.1007/

s00234-009-0583-y

 Viholainen , H. , Ahonen , T. , Cantell , M. , Lyytinen ,

 P. , & Lyytinen , H. ( 2002 ). Development of early

motor skills and language in children at risk for

familial dyslexia. Developmental Medicine and

Child Neurology , 44 , 761 – 769 .

 Warren , J. E. , Wise , R. J. , & Warren , J. D. ( 2005 ).

 Sounds do-able: Auditory–motor transformations

and the posterior temporal plane. Trends in

Neurosciences , 28 ( 12 ), 636 – 643 .

 Wassenberg , R. , Feron , F. J. , Kessels , A. G. ,

 Hendriksen , J. G. , Kalff , A. C. , Kroes , M. , . . .

 Vles , J. S. ( 2005 ). Relation between cognitive

and motor performance in 5- to 6-year-old

children: Results from a large-scale cross-sectional

study . Child Development , 76 ( 5 ), 1092 – 1103 .

 doi:10.1111/j.1467-8624.2005.00899.x

 Williams , D. L. , Goldstein , G. , & Minshew , N. J.

( 2006 ). Neuropsychologic functioning in

children with autism: Further evidence for

disordered complex information-processing. Child

Neuropsychology , 12 ( 4-5 ), 279 – 298 .

 Wilson , B. , Pollock , N. , Kaplan , B. , & Law , M.

( 2000 ). Clinical observation of motor and postural

skills: Administration and scoring manual

( 2nd ed. ). Framingham, MA : Therapro, Inc .

 World Health Organization . ( 2010 ). International

statistical classifi cation of diseases and health

related problems . Geneva, Switzerland : World

Health Organization .

 Zhu , J. L. , Olsen , J. , & Olesen , A. W. ( 2012 ). Risk

for developmental coordination disorder correlates

with gestational age at birth . Paediatric and

Perinatal Epidemiology , 26 ( 6 ), 572 – 577 .

 Zwicker , J. G. , Harris , S. R. , & Klassen , A. F. ( 2013 ).

 Quality of life domains affected in children with

developmental coordination disorder: A systematic

review . Child: Care, Health and Development ,

39 ( 1 ), 562 .

 Zwicker , J. G. , Missiuna , C. , Harris , S. R. , & Boyd ,

 L. A. ( 2010 ). Brain activation of children with

developmental coordination disorder is different

150 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

than peers. Pediatrics , 126 ( 3 ), e678 – e686 .

 doi:10.1542/peds.2010-0059

 Zwicker , J. G. , Missiuna , C. , Harris , S. R. , & Boyd ,

 L. A. ( 2012 ). Developmental coordination

disorder: A review and update . European

Journal of Paediatric Neurology , 16 , 573 – 581 .

 doi:10.1016/j.ejpn.2012.05.005

 Zwicker , J. G. , Yoon , S. W. , MacKay , M. , PetrieThomas, J. , Rogers , M. , & Synnes , A. R. ( 2013 ).

 Perinatal and neonatal predictors of developmental

coordination disorder in very low birthweight

children. Archives of Disease in Childhood , 98 ( 2 ),

 118 – 122 .

151

CHAPTER

6

Sensory Modulation Functions

and Disorders

 Shelly J. Lane , PhD, OTR/L, FAOTA

 Chapter 6

 Only recently has the professional literature begun to describe sensory modulation

dysfunction. Practicing clinicians desperately need rigorous study designs to

provide empirical data related to this disorder. Only through implementing

and reporting well-controlled, rigorous studies will investigators be able

to answer questions such as, Is SMD a valid syndrome? Does

occupational therapy help ameliorate the condition? What

are the underlying mechanisms in the disorder?

 — Miller, L. J., & Summers, C., 2001

Upon completion of this chapter, the reader will be able to:

✔ Describe sensory modulation function on a

cellular and behavioral level.

✔ Relate historical constructs relative to sensory

modulation dysfunction (SMD) to current

conceptualizations.

✔ Relate behaviors associated with sensory

modulation function and dysfunction to central

nervous system (CNS) structures.

✔ Refl ect on our current understanding of sensory

modulation disorders.

✔ Describe available research examining sensory

modulation disorders in children with and

without comorbid diagnoses.

LEARNING OUTCOMES

Purpose and Scope

 Sensory processing . . . sensory registration

. . . sensory integration . . . sensory modulation

. . . sensory reactivity. . . . We use these terms

both academically and clinically, yet from one

clinic to another, from one academic institution to another, and even from one profession

to another, the intended meaning of the terms

may differ. Adding complexity, some of these

terms suggest neural functions, some suggest

the outward behavioral manifestation of what we

assume to be neural functions, and some have

been used interchangeably to imply either. For

consistency, we have provided some defi nitions

in Chapter 1 (Sensory Integration: A. Jean Ayres’

Theory Revisited). Consistent with these defi nitions, and the model depicted in Figure 1-6 , we

have endeavored a move toward consistency in

this text, as was noted in Chapter 1 (Sensory

Integration: A. Jean Ayres’ Theory Revisited).

 In considering sensory modulation, we begin

with a child, depicting one of the sensory modulation concerns clinicians have identifi ed. This is

followed by reiterating some defi nitions specifi c

to this chapter, and then we move to examine

modulation, fi rst on a cellular level and then on

systems and behavioral levels. Next, we explain

the concept of sensory modulation dysfunction

(SMD). Hypothesized links to the limbic system

and a proposed relationship between modulation

dysfunction and stress leads to a discussion of

152 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

these issues as well. We look at SMD as a whole

and then discuss specifi c types of modulation

dysfunction within the tactile and vestibularproprioceptive systems. We close with a brief

look at sensory over-reactivity within other

sensory systems.

CASE STUDY ■ MICHAEL

 Observed in the classroom, 10-year-old

Michael appears not to be paying attention to

the lesson at hand. He is very quiet and does

not volunteer information that adds to the discussion under way. His teacher questions if he

is processing the information at all. Michael

does not engage with other children to any

great extent, and he plays alone on the playground. Currently Michael is classifi ed by the

school system as “other health impaired.” He

has an individualized education program (IEP)

and receives both educational assistance and

occupational therapy. His IEP states that one

of his needs is for the opportunity to get more

movement and deep pressure input during the

day in order to improve his ability to attend and

process. Incorporating this input throughout the

school day is becoming diffi cult because, in

fi fth grade, Michael ’ s teachers are not comfortable with these accommodations in the classroom, and Michael is less comfortable with

anything that makes him appear different from

his classmates.

 Recently a Sensory Profi le TM 2 (SP2) ( Dunn,

 2014 ) was completed. It can be scored as

sensory system scores and summed into quadrant scores. Scores in each sensory section are

as follows:

• Tactile: 29, much more than others

• Auditory: 6, less than others

• Visual: 7, less than others

• Movement: 27, much more than others

• Proprioception: 5, similar to the majority

of others

 Behavioral section scores included:

• Conduct: 25, more than others

• Social emotional: 30, similar to the

majority of others

• Attentional: 27, more than others

 Quadrant scores indicated that Michael

shows indicators in all quadrants. He shows

over-responsivity to touch, which is largely

responsible for the high score in the avoider

 quadrant (score of 52; more than others).

Scores in response to his visual and auditory

environment suggest some reduced responsivity, as do his responses to movement, refl ected

on the SP2 as poor sensory registration (score

of 66; much more than others). Michael also

seeks additional movement and deep touch

input throughout his daily routines (score of

65; much more than others). Overall, it was

determined that Michael has a defi cit in sensory

modulation, most clearly seen with diminished responsivity in some sensory systems;

over-responsivity to touch; and sensory-seeking

behavior within the vestibular and proprioceptive systems. These modulation diffi culties are

linked to both behavioral and emotional regulation problems, presenting as diffi culty paying

attention to tasks at hand, a tendency not to

attend within an active environment, and a high

level of emotional reactivity to sensory input.

These diffi culties are very consistent with those

over which his mother, Mrs. S., has expressed

concern and are of a nature to impair his ability

to work within the classroom.

Sensory Modulation

 Modulation of sensory input is critical to our

ability to engage in daily occupations ( BarShalita, Vatine, & Parush, 2008 ). Filtering of

sensations and attending to those that are relevant, maintaining an optimal level of arousal,

and maintaining attention to task all require modulation (S. J. Lane, Lynn, & Reynolds, 2010 ).

When modulation is inadequate, attention may

be diverted continually to ongoing changes in the

sensory environment. We become distracted and

attend to all input; this alters our arousal state

such that it is no longer optimal.

Modulation as a Physiological Process

at the Cellular Level

 According to the Cambridge Dictionaries

online, to modulate means “to change something, such as an action or a process, to make it

more suitable for its situation” ( http://dictionary

.cambridge.org/dictionary/british/modulate ).

Within the central nervous system (CNS), modulation is refl ected in neuronal activity that is

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 153

enhanced or dampened in response to various

sources of input to meet current demands. At

the cellular level, both sensory receptor cells in

the periphery and neuronal cells within the CNS

may become more or less responsive to input. An

incoming sensory signal is received by a receptor

specifi c to that signal. The receptor can be highly

responsive to input or, through time, can adapt

to continued input and cease to respond. After

reception, a stimulus must be transduced into

an electrical signal to be carried to the CNS. As

noted in Chapter 4 (Structure and Function of the

Sensory Systems), transduction involves changing the energy of the initial signal (e.g., sound

waves for the auditory system or movement for

the vestibular system) into electrical and chemical energy. When these changes are of suffi cient

strength, an electrical signal, known as an action

potential, is generated and carried to the cell

body of the fi rst order neuron. From this initial

point of entry, the electrical signal can be propagated to interact with the cell bodies, other axons,

or dendrites of other neurons within the CNS.

 At the synapse, or point of interaction

between neurons, the electrical signal changes to

a chemical signal and activates neurotransmission. Neurotransmitters are released and travel

across the synaptic cleft to interact with specifi c receptors on the postsynaptic membrane.

 Figure 6-1 depicts this process schematically. Neurotransmitters can be either excitatory or inhibitory. Some have been shown to always be either

excitatory or inhibitory; for instance, glutamate

is an excitatory neurotransmitter found widely

throughout the brain. Interestingly, glutamate

is the precursor, or building block, for gammaaminobutyric acid (GABA), the chief inhibitory

neurotransmitter in the CNS. Neurotransmitters

such as dopamine or serotonin are either excitatory or inhibitory, depending on the characteristics of the receptor with which they interact. As

an example, there are at least fi ve types of dopamine receptors in the brain, which can be broadly

grouped into D-1 like and D-2 like families. At

some D-1 like sites, dopamine opens sodium

channels, leading to excitation and a neural signal

being sent on; at other D-1 like sites, dopamine

opens potassium channels instead, inhibiting

signal propagation. Action at D-2 like receptors

is almost always inhibitory ( Purves et al., 2011 ).

Receptors for serotonin are even more complex,

and are beyond the scope of this discussion.

 For simplicity in understanding balancing of

excitation and inhibition, we will consider hypothetical transmitters interacting with one type

of receptor, resulting in an action that is always

excitatory or inhibitory. Because more than one

axon makes contact with the same postsynaptic neuron, potentially there will be competing

inputs, some excitatory and others inhibitory and

some strong and others weak. Thus, no single

input is likely to excite the postsynaptic membrane suffi ciently to send the message on further.

What determines if the signal will be further

propagated is, to some extent, the algebraic

sum of all inputs. Factors, such as the strength

and frequency of input and the location of the

synapse relative to the cell body, infl uence this

sum as well. Thus, modulation at the cellular

level comes from activation of specifi c inputs

to a cell; increasing excitatory inputs results in

the postsynaptic cell fi ring and sending the information forward. Increased inhibitory inputs will

“block” further transmission of the impulse. In

 Figure 6-2 , this is diagrammed simplistically.

Here there is a preponderance of inhibitory inputs;

thus, the target cell (shaded) will be inhibited

from fi ring.

 As an example, consider a very simplifi ed

version of the nervous system, such as that

depicted in Figure 6-2 . Neuron A carries sensation from a sharp, quick pinch and releases an

excitatory neurotransmitter onto the postsynaptic

membrane. Intense or repeated signals activate

the postsynaptic cell to further transmission of

the signal, say to the thalamus, where the sensation of pain could be identifi ed. However, if the

pinched spot is pressed on or rubbed, another set

of incoming neurons is activated (e.g., neuron B),

carrying deep pressure. Assume this new input

makes a connection with the same central neuron

but leads to the release of an inhibitory transmitter. If the signal ratio were one to one (i.e., one

pinch activation for one deep pressure rub activation) with similar strengths and contact points,

then one signal would cancel the other and there

would be no propagation of input and no sensation of pain. However, if the pinch is intense or

prolonged, an increase in the frequency or intensity of transmission regarding the deep pressure

neuron might be needed to cancel the sensation

of pain completely. Even without a complete

cancellation, transmission of this painful input

is modulated, or not as intense as it would have

154 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

FIGURE 6-1 Synapse and synaptic transmission. Neuron A is shown synapsing with neuron B. This synapse

is shown in greater detail in C, where the presynaptic vesicle, synaptic cleft, and postsynaptic membrane are

indicated. Neuron A is also shown, surrounded by projections from an oligodendrocyte (a glial cell; see

Chapter 2, Sensory Integration in Everyday Life, for more information on neurons and glia). Adapted from

Gilman and Newman, 1992, and reprinted with permission from Gilman, S., & Newman, S. W. (1992).

Essentials of clinical neuroanatomy and neurophysiology (9th ed., p. 4). Philadelphia, PA: F.A. Davis.

been without the deep pressure. In Figure 6-2 ,

neuron C may come from higher level centers

in the brainstem or thalamus. The combination

of inhibition from the periphery and the CNS in

this case cancel further transmission of pain; it

does not reach the level of the CNS required for

sensory detection.

 Clearly, single cell input to the CNS offers

a greatly oversimplifi ed perspective on modulation, but it does provide a useful place to

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 155

start. The interconnectivity of the CNS is very

complex, and many factors infl uence modulation. Still, the bottom line at the cellular level

is that some inputs are excitatory and some are

inhibitory; some are strong and some are weak;

some are fast and some are slow. The algebraic

sum of these factors, along with some essential

characteristics of the synapse, determines what

the CNS experiences from the periphery and

what it does with this information. If we make

a cautionary link to the next level, these same

concepts can be used to develop a parallel understanding of modulation from a sensory system

and behavioral level.

Modulation at the Level of Systems

and Behavior

 Separating neurophysiological systems from

behavior is diffi cult because we only see systems

at work when we observe behavior. Thus, we will

look at behavioral and neurophysiological modulation together. However, you are encouraged to

distinguish between descriptions of behavior and

those of neurophysiological processes.

 If we view the cellular model more realistically, it becomes clear that many neurons are

receiving inputs from multiple sources simultaneously. CNS structures process incoming

input and generate responses that refl ect acceptably modulated behavior. Ayres ( 1979 ) defi ned

modulation as “the process of increasing or

reducing activity to keep the activity in harmony

with all functions of the nervous system”

(p. 182). Modulation at the cellular level allows

a person to respond at the behavioral level to relevant input, not to respond to what is irrelevant,

and to do so in a manner that promotes adaptive environmental interaction. The link between

modulation and behavior has been reinforced in

research fi ndings, indicating that adequate modulation facilitates engagement in satisfying and

meaningful occupations ( Bar-Shalita et al., 2008 ;

 Reynolds, Bendixen, Lawrence, & Lane, 2011 ;

 Reynolds & Lane, 2008 ) and that diffi culties

with modulation can negatively impact quality

of life (QoL; Bar-Shalita, Deutsch, Honigman, &

Weissman-Fogel, 2015 ).

 The act of balancing excitatory and inhibitory

inputs in the CNS and responding only to those

that are relevant (i.e., our work to “maintain

harmony”) goes on subconsciously. For most,

the ability to generate a modulated behavioral

response is present, albeit unrefi ned, at birth. For

instance, a fatigued infant begins to cry, fi nds a

thumb, and begins to suck. The clinician may

infer that by using somatosensory input (deep

pressure to the mouth), the infant has modulated

his or her emotional response and has found a

way to behave in a socially acceptable manner—

to self-calm. Deep pressure and touch within the

mouth, transmitted through the somatosensory

FIGURE 6-2 Balancing excitatory and inhibitory inputs. This neuron (shaded) receives both excitatory (neuron A,

white) and inhibitory (neurons B and C, gray) inputs. In this fi gure the sum of inputs would favor inhibition of

further neurotransmission.

A

B

C

+

-

-

156 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

system, provided suffi cient inhibitory input to

the cells in the CNS to modulate arousal.

 As the nervous system matures, develops

more connections, and grows myelin, the ability

to modulate one sensory system ’ s activity, via

input to another system, also refi nes. This internal growth and development is supplemented by

environmental inputs, instilling an understanding

of appropriate environmental interactions and

how such an interaction is generated ( Purves

et al., 2011 ).

 The art of modulating behavior through the

use of sensation becomes personalized. What

works for one does not necessarily work for

another. One mother learns early on that close

chest-to-chest contact is the only means of quieting her infant. Rocking, bouncing, and patting

all seem to increase the infant ’ s agitation rather

than help her settle down. In periods of quiet

alertness, this baby enjoys these latter inputs,

but when she is upset, they only make it worse.

Another mother fi nds that her infant needs to be

rocked or jiggled; cuddling alone is insuffi cient

to help this second baby calm down. Different

sensations work to help these infants modulate

their arousal and anxiety. This was also true for

Michael. He found tactile input discomforting

rather than comforting; his ability to interpret

and modulate tactile input was compromised; in

contrast, he found movement and proprioception

settling.

 To further illustrate this concept, consider

toddlers in a playgroup using a slide. We see

one child, Beth, who is very excited about this

opportunity. She has been running in circles from

the bottom of the slide to the stairs for several

minutes, and this seems to be a great way to use

up her energy. However, she gets more and more

excited each time she gets to slide down the slide.

She runs back to the stairs for more but seems to

become less coordinated with each turn, fi nally

slipping on the stairs on the way up and screaming in frustration. She requires the intervention

of a child-care worker before she can calm down

and move on to another activity.

 Sam, on the other hand, has been sitting and

watching, seemingly not looking forward to a turn

on the slide, or any other activity for that matter.

The care provider guides him to the slide, assists

him in the climb, and offers support the fi rst

time down. He smiles, walks back to the steps,

and looks for assistance to do it again. The next

HERE ’ S THE EVIDENCE

Bar-Shalita and Cermak ( 2016 ) wished to examine

the relationship between what they termed Atypical Sensory Modulation and psychological distress

(e.g., anxiety) in the general population. They

defi ned ASM as an aspect of poor sensory processing that negatively impacted the ability to grade

responses to single or multisensory inputs, and

indicated that ASM might be refl ected in over-responsivity, under-responsivity, or sensory seeking

(SS). Participants in their study were adults with

no identifi ed disorders or family history of psychopathology. Participants completed the Sensory

Responsiveness Questionnaire-Intensity Scale, which

the authors had developed in an earlier study. On

completion of the SRQ-IS, the group of participants

was subdivided into those with ASM (greater than

or equal to 2 SD from the SRQ-IS mean; 12.75%

of the total group, n = 26) and a comparison

group of individuals scoring within the cutoff range

on the SRQ-IS (mean ± 2 SD; n = 178). All participants completed the Brief Symptom Inventory

(BSI), a tool that identifi es psychological symptoms

through a series of psychological dimensions. The

Short Form-36 Health Survey was also completed

to provide insight into perceived QoL in areas of

physical health. Investigators found that adults with

ASM had more psychological symptoms than the

comparison group. Although scores were within a

typical range for both groups, investigators suggest

that the overall increased symptoms might refl ect

a risk factor for the future. QoL related to physical health was substantially lower for adults in the

ASM group, leading investigators to suggest that

QoL for otherwise typical adults was “vulnerable.”

In a fi nal analysis, these investigators found that

together QoL and ASM predicted psychological distress. Investigators indicate that psychological distress is itself a risk factor for the development of

other mental health conditions, and as such ASM,

or SMD, might also be considered a risk factor for

later development of mental ill-health. Early identifi cation and intervention may be the best practice

for these individuals.

Bar-Shalita, T., & Cermak, S. A. (2016). Atypical sensory modulation and psychological distress in the general population. American

Journal of Occupational Therapy, 70, 1–9.

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 157

time, Sam climbs alone, checks in with the

care provider, and slides alone; another smile

emerges. After four or fi ve slides, he is fi nished

and becomes invested in some blocks and cars in

another part of the room.

 In this instance, the same activity, sliding,

increased arousal in both children, but the input

had a very different modulatory impact on their

behavior. For Beth, the slide was fun but was

disorganizing in the long run. Based on her

behavior, we infer that the ongoing vestibular

and proprioceptive sensations raised her level

of arousal beyond the point of adaptive environmental interaction. She needed to pull back

and receive another form of input (i.e., comforting from the caregiver) before she was ready

for another activity. For Sam, the sliding was

activating. His apparently low level of arousal

and sensory detection were increased through

this activity, and, for Sam, this was critical for

improving his ability to generate subsequent

environmental interactions.

HERE ’ S THE POINT

• Modulation of sensation needs to be

considered at both a cellular and behavioral

level.

• At the cellular level, modulation involves

the actions of neurotransmitters on neuron

receptors. These actions may inhibit a

sensory signal from being sent forward,

excite the receptor to support transmission

of the signal, or serve to moderate the

signal.

• We see the behavioral outcome of cellular

modulation reflected in activity; adequate

cellular modulation supports our ability

to respond to sensation behaviorally in a

manner that promotes adaptive environmental

interaction and facilitates engagement in

meaningful occupations.

Sensory Modulation Dysfunction

 Modulate: “To change or adjust (something) so

that it exists in a balanced or proper amount”

( Merriam Webster Online, 2015 ). Disorders of

sensory modulation then refl ect diffi culty with

this balance process; we see either too little

adjustment or too much adjustment. Importantly

from a sensory integrative perspective, “. . . it

is a mismatch between the external contextual

demands of a person ’ s world (e.g. culture, environment, tasks, and relationships) and a person ’ s

internal characteristics” ( Hanft, Miller, & Lane,

 2000 , p. 1). Sensory modulation disorders have

been described slightly differently by recent

investigators. In the next section we examine the

evolution of these defi nitions.

A Brief Historical Overview

 Ayres described tactile defensiveness as early as

1964, linking it with hyperactivity and inattention ( Ayres, 1964 ). In this theoretical manuscript,

Ayres described the features of tactile defensiveness as an imbalance between protective and

discriminative systems, resulting in discomfort

with touch and a desire to escape from it. She

further suggested that tactile defensiveness might

be seen in combination with defensiveness in

other systems ( Ayres, 1972 ). This was extended

by Knickerbocker ( 1980 ), who introduced the

term sensory defensiveness to describe a disorganized response to sensory input across more

than one sensory system. Specifi cally, she implicated olfactory (O), tactile (T), and auditory (A)

systems, terming this the “OTA triad.” Children

with such sensory defensiveness were characterized as overly active, hyper-verbal, distractible,

and disorganized. Knickerbocker ( 1980 ) also

described sensory dormancy, characterized by

disorganized and immature behavior, resulting

from excessive inhibition of incoming sensory

input and a lack of sensory arousal. Dormancy

could be observed in the olfactory, tactile, and

auditory systems. Knickerbocker described a

child experiencing sensory dormancy as being

quiet and compliant. The constructs of sensory

defensiveness and dormancy were further considered by several other theorists and investigators

( Cermak, 1988 ; Lai, Parham, & Johnson-Ecker,

 1999 ; Royeen, 1989 ; Royeen & Lane, 1991 ).

And, although these sensory responses appear

to form a continuum, there was not suffi cient

evidence found to support this relationship.

Although clinicians address subcategories of disorders, including tactile defensiveness; gravitational insecurity; and defensiveness to smell and

taste, sound, and light; the work of McIntosh,

Miller, Shyu, & Hagerman ( 1999 ) suggested a

more general underlying SMD in which poor

158 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

modulation in the different systems appears to

be related.

 Other authors ( Dunn, 1997, 2014 ; Parham &

Mailloux, 1996 ; Wilbarger & Wilbarger, 1991 )

indicated that sensory modulation was multidimensional, rather than representing a basic continuum; that children may not routinely over- or

under-respond to sensation but instead may show

sensory over-responsiveness to some sensations

and under-responsiveness to others. And, there

may be responsiveness changes across the span

of a day, and in different contexts. Disorders of

modulation then may refl ect the child ’ s diffi culty

fi nding the middle ground, across different contexts, where the appropriate level of modulation

exists to allow him or her to interact adaptively

with the environment. The resultant behaviors

refl ect a cascade of events within the CNS that

affect attention, arousal, emotional stability, and

cognitive processing.

 Miller, Anzalone, Lane, Cermak, and Osten

 ( 2007 ) proposed a sensory processing nosology

in which sensory modulation was one component

of overall sensory integrative and processing

defi cits. This model paralleled that proposed

and discussed by Ayres and others, indicating

that disorders of modulation refl ected diffi culty

processing the degree, nature, or intensity of the

sensory input, resulting in behaviors that failed to

match environmental expectations and demands

in a manner that was appropriate developmentally.

The categories of over- and under-responsivity

were described, indicating that sensory overresponsivity (SOR) might be refl ected in behaviors ranging from negativity, aggression, and

impulsivity to withdrawal, to avoidance or passivity. SOR was also linked with sympathetic

nervous system (SNS) activation, which itself

is characterized by the fi ght, fl ight, and fl ee

responses ( Miller et al., 1999 ; Miller et al.,

 2007 ). Sensory under-responsivity (SUR) was

identifi ed as seeming unaware of a sensation of

typical intensity and duration. Children evidencing SUR might appear to ignore input or fail to

notice it. SS was also included, consistent with a

model proposed by Dunn in 1997; it was defi ned

as craving sensation of high intensity or long

duration. Children engaging in SS create opportunities for sensation (e.g., drumming on every

surface they pass as they walk down the hall).

Importantly, SS as a modulation disorder was

seen as an unusual need for intense, prolonged,

or unusual input. Authors acknowledged that

children with typical modulation might seek sensation. For instance, a young child who learns to

climb onto and jump off the couch might repeat

this pattern of movement several times, laughing

with the intensity of his or her landing. He or

she would, however, move on to something else.

Miller and colleagues have continued to investigate aspects of sensory modulation subtyping.

Using a newly developed tool, the Sensory Processing 3 Dimensions, they have substantiated

these same three subtypes (SOR, SUR, and

sensory craving) ( Schoen, Miller, & Sullivan,

 2014 , 2016). More information is available in

 Chapter 15 (Advances in Sensory Integration

Research: Clinically Based Research).

 Dunn ( 1997, 1999 ) proposed and recently

updated ( Dunn, 2014 ) a conceptual model that

links the neurological threshold to behavioral

responsiveness ( Fig. 6-3 ). She described two

continua, one related to neurological threshold

and another related to self-regulation. Dunn also

defi ned four sensory processing patterns that

refl ect the intersection and interaction of the

continua: poor registration, sensation seeking,

sensation avoiding, and sensory sensitivity. Registration is defi ned as a sensory modulation defi cit

characterized by high neurological thresholds and

passive behavioral self-regulation; children with

this pattern of processing respond less to available sensation, missing aspects of sensory input.

FIGURE 6-3 Dunn ’ s conceptual model that links the

neurological threshold to behavioral responsiveness.

HIGH

RG

AV

SK

SN

LOW

PASSIVE

ACTIVE

H

L

P A Neurological threshold continuum

Self-regulation continuum

Avoiding/Avoider

Sensitivity/Sensor

Registration/Bystander

Seeking/Seeker

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 159

Dunn termed those with this pattern as bystanders.

Sam ’ s environmental interactions refl ect a degree

of under-responsiveness to sensations available

in the environment and through activity; he needs

a lot of input to get going. Using Dunn ’ s terminology, he has a higher than usual neurological

threshold and relies on passive self-regulation.

Coupling high neurological threshold with active

self-regulation leads to seeking: Children who

are driven to obtain sensation in greater intensity, frequency, or duration than that routinely

available. Michael would be identifi ed with this

pattern of sensory modulation; he needs intense

vestibular and proprioceptive sensations to allow

for appropriate environmental interactions. The

other two patterns within Dunn ’ s framework

refl ect low neurological thresholds. Pairing a low

threshold with passive self-regulation results in

sensitivity, whereas low threshold with active

self-regulation results in avoiding ( Dunn, 2014 ).

 Relatively recently, researchers have begun

to examine links among sensory modulation

disorders, physiological responses to sensation,

and behavior. Although no cogent and unifi ed

model has emerged, some interesting characteristics have been identifi ed. First, although

sensory modulation defi cits have been identifi ed in children with diagnoses such as autism

spectrum disorder (ASD) and attention defi cithyperactivity disorder (ADHD) ( Cheung &

Siu, 2009 ; Dunn & Bennett, 2002 ; Kern et al.,

 2007 ; Kientz & Dunn, 1997 ; Wiggins, Robins,

Bakeman, & Adamson, 2009 ), children with

sensory modulation defi cits and no identifi ed

comorbidities also have been characterized

( Ben-Sasson, Soto, Heberle, Carter, & BriggsGowan, 2013 ; Reynolds, Lane, & Gennings,

 2009 ). Electrophysiological fi ndings suggest that

children with SOR show SNS over-reactivity to

sensation ( Mangeot et al., 2001 ; Schoen, Miller,

Brett-Green, & Nielsen, 2009 ). In addition, elevated anxiety has been linked with SOR (S. J.

 Lane, Reynolds, & Thacker, 2010 ).

Proposed Central Nervous System Links

to Sensory Modulation Dysfunction

 Recent examinations of sensory modulation disorder have moved the fi eld forward in understanding neurological correlates of this concern.

Most research has focused on sensory overresponsiveness and has examined links with the

autonomic nervous system (ANS) and the stress

response characterized by cortisol. A summary

of this research can be found in Chapter 15

(Advances in Sensory Integration Research:

Clinically Based Research) and Chapter 16

(Advances in Sensory Integration Research:

Basic Science Research), respectively.

Theoretical and Hypothesized Links

 The descriptors used in the previous section,

related to emotional responses, attentional and

arousal mechanisms, and sensory fi ltering, have

contributed to theories and research relative to

the mechanisms underlying modulation defi cits

in the CNS. These links are examined in the next

section, and, when available, research fi ndings

relative to the relationships are discussed.

Sensory Modulation and the Limbic System

 The group of structures we commonly refer to as

the limbic system, and link to emotional regulation,

may not be a unitary system ( Bear, Connors, &

Paradiso, 2015 ). As noted previously, clinicians

and researchers had been describing behaviors

related to limbic system function since the early

1960s, and there are clear links to sensation.

Examining this relationship further, Royeen and

Lane ( 1991 ) hypothesized that modulation dysfunction may have its roots in limbic regions and

the hypothalamus. The source of this proposal

was in the functions of these structures. Called

the “mediator of all things emotional” ( Restak,

 1995 , p. 18), Restak indicated that the limbic

system includes three cortical areas (i.e., the

cingulate gyrus, septum, and parahippocampal

gyrus) and the gray matter areas of the hippocampus and amygdala ( Fig. 6-4 ). Some scientists

include the hypothalamus as a component of this

group of structures (e.g., Siegel & Sapru, 2015 ;

see Fig. 6-4 ); the hypothalamus has been linked

with governing emotional expression through a

reciprocal loop that connects the (neo) cortex

and cingulate cortex, and the cingulate with the

hippocampus, hypothalamus, and thalamus ( Bear

et al., 2015 ). Limbic regions receive input from

all cerebral lobes and connecting fi bers and

project back to these areas; there are also extensive connections among limbic structures. Limbic

regions are highly connected with the hypothalamus and related regions, and, as such, serve a

function of modulating hypothalamic infl uences

on somatic and ANS activity. Limbic structures

160 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

play a role in learning and memory; eating and

drinking behaviors; aggression; sexual behavior;

and, importantly, motivation and expression of

emotion ( Siegel & Sapru, 2015 ). The processing

of sensation is a prominent function of some

limbic structures. As such, the limbic system is a

likely candidate for involvement in SMD.

 Early on, Royeen and Lane ( 1991 ) had suggested that involvement of the limbic system:

(a) provides an explanation for the emotional or

social diffi culties often accompanying tactile and

sensory defensiveness, (b) accounts for the presence of defensiveness or dormancy across sensory

systems, and (c) allows for extreme shifts or

inconsistencies in responsivity (from defensiveness to dormancy) that may be observed in an

individual either with regard to a single sensory

system or across sensory systems (p. 122).

 Even as we learn more about limbic structures, this continues to have theoretical logic

and is beginning to engender some empirical

support. For instance, the research of Miller and

colleagues ( 1999 ), with children with fragile X

syndrome, demonstrated differences in electrodermal response (EDR) to sensory challenge

between children with fragile X syndrome and

age- and gender-matched controls. The EDR is a

refl ection of SNS activation, mediated in part by

the limbic-hypothalamic system ( Edelberg, 1972 ;

 Fowles, 1986 ). Additional studies of individuals

with fragile X syndrome have implicated the

caudate, hippocampus, and thalamus ( Gothelf

et al., 2008 ; Lee et al., 2007 ; Reiss, Abrams,

Greenlaw, Freund, & Denkla, 1995 ; Reiss, Lee, &

Freund, 1994 ; A. Schneider, Hagerman, & Hessl,

 2009 ). Using fMRI, Green and colleagues ( 2013 )

have similarly documented increased activity in

regions of the limbic system (amygdala, hippocampus, and orbito-frontal cortex), as well as in

the primary sensory cortex, during sensory challenge in individuals with ASD. Thus, increasingly we are establishing evidence indicating a

link between the sensory modulation differences

and limbic processing, although understanding

these links requires ongoing investigation.

 Because the limbic regions may be involved

in modulation, a look at the functions associated

with some of its structures is warranted. Studies

of the limbic system have largely used animal

models. As always, caution must be exercised in

making the leap from animal studies to function

within the human nervous system. Nonetheless,

much can be learned by examining this work.

 The septal region (see Fig. 6-4 ) has functions

that parallel those of the hippocampus because

it serves as a relay between the hippocampus

and the hypothalamus. It receives input from the

olfactory and limbic systems, and, along with

projecting to the hypothalamus, fi bers project

to the epithalamus and other midbrain regions

FIGURE 6-4 The limbic system is less an actual system than a group of structures. The structures include the

amygdala, hippocampus, cingulate gyrus, septum, fornix, and mammillary body on each side of the brain.

Sometimes the hypothalamus is also included in this system.

Left

fornix

Septum

Right

olfactory

bulb

Hypothalamus

Left

mammillary

body

Left

amygdala

Left

hippocampus

Left

thalamus

Left

cingulate

gyrus

Right

cingulate

gyrus

Longitudinal

fissure

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 161

( Waxman, 2010 ). The septum is thought to exert

an inhibitory infl uence on the ANS and to play

a role in the use of environmental stimulation; it

permits the organism to attend to any stimulus in

the environment, even those having low stimulus

value ( Isaacson, 1982 ). Thus, in a normal state,

the septal region may play a role in our ability

to attend to and interact successfully with the

environment.

 Lesions of the septal region have been shown

to result in transient hyperemotionality in many

rodents and humans ( Isaacson, 1982 ). The

increased emotionality can be reduced with handling and is less severe when an animal experiences the lesion during its youth. In addition,

some animals with lesions appear to demonstrate exaggerated defensive reactions and show

hyperresponsiveness to handling, light touch (air

puffs), poking with a stick, temperature changes,

light, and sounds ( Donovick, 1968 ; Fried, 1972 ;

 Green & Schwartzbaum, 1968 ; Grossman, 1978 ;

 Olton & Gage, 1974 ). This hyperresponsivity is

characterized by increases in motor activity. It

is tempting to hypothesize then that this region

is linked with SOR, and the “vigilant” behaviors

(attending to all sensory input) often associated

with SOR. Were Michael ’ s diffi culty attending,

introduced earlier, linked more to appearing

hypervigilant to all stimuli in his sensory environment, we might be concerned about function

within this limbic region.

 The cingulate gyrus (see Fig. 6-4 ) is a

complex structure with numerous connections;

it receives input from the hippocampus and has

reciprocal connections with the anterior nucleus

of the thalamus and portions of the temporal,

parietal, and prefrontal association areas. It also

sends input to the dorsal medial nucleus of the

thalamus, a connection thought to be important

in the affect associated with perception ( Kingsley, 2000 ). As with other limbic structures, we

are still learning about the various physiological

functions associated with the cingulate gyrus;

several functions have been linked with regions

of the cingulate gyrus, including affect regulation, visceromotor control, response selection,

visuospatial processing, and memory access. It

may play a role in attaching emotional quality

or meaning to sensory input, also in concert with

the amygdala.

 Bear and colleagues ( 2015 ) identify affective aggression as the emotional response of an

animal in the presence of a threatening stimulus.

In cats, for example, this might be the presence

of another animal within its territory or posing a

threat to a litter of kittens. The affective behaviors associated with such rage are strongly inhibited by output from the amygdala and facilitated

by connections from the septal area and other

limbic regions. This suggests a modulatory role

in affective rage. Although likening affective

aggression in animals to sensory modulation

defi cits is inappropriate, examining this mechanism gives us food for thought because it defi nes

the limbic system as playing a role in the modulation of behavior resulting from environmental

input that is perceived to be threatening. Referring back again to Michael, he does not demonstrate what would be considered “affective rage”;

instead, he tends to withdraw from sensory

stimuli to the point that his teacher questions

whether he is adequately processing the information he receives.

 Aside from its role in olfaction, current

knowledge suggests a highly important role

in fear conditioning and emotion recognition

for the amygdala (see Fig. 6-4 ). Years ago,

 Pribram ( 1975 ) suggested that the amygdala

made important contributions to an organism ’ s

ability to orient and detect sensory input; more

recent work suggests that this structure is linked

with recognition of emotional expression, especially fear, anger, sadness, and disgust ( Siegel &

Sapru, 2015 ). Amygdala activation has been

linked with increased vigilance and attention,

along with the expression of anxiety and fear.

Recent work of Bruneau, Jacoby, and Saxe

 ( 2015 ) links the amygdala with the processing

of other people’s negative emotions (emotional

empathy); the same is not true for other people ’ s

physical pain. Activation of the amygdala has

long been associated with control of one ’ s own

emotional responses to distressing input. Reciprocal links between the amygdala and the frontal

cortex may serve as a mechanism for attaching

emotional signifi cance to sensory input ( Siegel &

Sapru, 2015 ). The amygdala has numerous connections with the hippocampus. This relationship allows amygdalar activity to infl uence ANS

functions. We might consider the possibility that

some of the avoidance behaviors associated with

SMD may be associated with the attachment of a

negative emotional response to that sensory input

within the amygdala.

162 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 The hippocampus (see Fig. 6-4 ), another

limbic structure, also has been hypothesized to

play a role in sensory modulation. Interestingly,

this structure is less linked with emotional regulation and more linked with spatial mapping

and memory, leading to the suggestion that this

structure is not associated with emotional regulation ( Bear et al., 2015 ). A large number of fi bers

link the hippocampus to the cortex. Functions

associated with this structure include learning

and memory, mediation of aggressive behavior

(via connections in the septal region), and autonomic and endocrine functions (via connections

with the hypothalamus) ( Siegel & Sapru, 2015 ).

This structure is considered highly important in

memory consolidation, moving memories from

short to long term. Siegel and Sapru suggested

memory consolidation may be lost with hippocampal lesions because the processing of sensory

input during learning is impaired. Hippocampal

lesions result in a wide variety of behavioral

alterations that seem to be related to an animal ’ s genetic background and to the conditions

under which a behavior was elicited. Here again,

extreme caution must be taken in generalizing

from animal studies to humans. However, hippocampal lesions result in animals’ failing to persist

in new tasks; they readily begin a goal-oriented

task but will not stay with it to completion.

There is also an increase in activity in some situations, especially during “open-fi eld” testing.

This increased movement is not associated with

increased exploration; the animal seems to move

about a great deal but fails to use the environmental information available from this increased

movement effectively.

 Finally, a role for the hypothalamus (see

 Fig. 6-4 ) in the process of sensory modulation

has been suggested. This structure maintains an

important and reciprocal relationship with the

limbic structures and is often included in discussions of this system. It integrates information from the cortex (fi rst processed through the

amygdala and hippocampus) with input from

the spinal cord and brainstem. In this respect, the

hypothalamus is a control center for ANS mechanisms ( Siegel & Sapru, 2015 ). Outputs from the

amygdala project to the lateral hypothalamus to

inhibit affective rage; as such, it is associated

with the expression of this response. Dysfunction in the hypothalamus in humans, secondary

to disease or injury, may be responsible for the

onset of attack behavior and physically violent

outbursts ( Bear et al., 2015 ).

 Thus, the purported functions of limbic and

hypothalamic structures are consistent with modulation of sensory input. These structures play a

role in attending to and processing environmental stimuli, attaching meaning and emotional

signifi cance to sensation, and the establishment

of memory. Furthermore, dysfunction in regions

of the limbic system elicits behaviors such as

increased sensory responsivity, increased emotionality, and aggressive behaviors. To some

extent there are parallels between these indicators of function and dysfunction with those

identifi ed by practitioners in children with SMD.

As noted, Michael exhibits some characteristics of poor sensory modulation; for Michael,

however, there are fewer concerns related to

limbic region function than diffi culty mediating

attention. Importantly, there are noted differences

between humans and animals, and any extrapolations between the two must be hypothetical until

further work is done.

Sensory Modulation and Arousal

 Arousal is often found in neurophysiology texts

to be tied to wakefulness and consciousness.

The literature on disorders of sensory modulation uses terms linked with arousal (arousal,

hyperarousal, hyperverbal, quiet, compliant) to

describe sensory modulation defi cits, indicating a

behavioral link. Arousal, or cortical activation, is

a function of the reticular formation; it is dependent on sensory input. Activation of the cortex

by the reticular formation ( Fig. 6-5 ) is critical in

that it changes the receptivity of cortical sensory

neurons to sensory input that comes in through

individual sensory system pathways. Importantly, the reticular formation is also linked with

reduced sensory responsivity, such as that seen

in inhibition of pain pathways ( Siegel & Sapru,

 2015 ). Thus, logic tells us that the modulation of

sensory input has a relationship with arousal.

 The reticular formation is a diffuse system that

runs through the brainstem. In its role of regulating arousal and consciousness, it receives input

from every major sensory pathway and projects

to the cortex (both directly and via nonspecifi c

thalamic nuclei) to maintain arousal levels. The

presentation of new or novel stimuli increases

reticular activation of the cerebral cortex; removal

of sensory input decreases cortical activation

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 163

FIGURE 6-5 The reticular formation runs throughout the brainstem, forming a network of fi bers and nuclei that

widely infl uence CNS function. It receives input from every sensory system, and from other regions of the brain.

Efferent fi bers infl uence postural tone; other connections infl uence visceral, autonomic, and endocrine activity,

as well as arousal activity and consciousness.

and leads to a gradual decrease in wakefulness. Sleep, however, is not simply a result of

the withdrawal of input; instead, it results from

an interaction among several neurotransmitter

systems with their cell bodies in regions of the

reticular formation and the hypothalamus. In

response to novel or challenging stimuli, the cholinergic neurotransmitter pathways to the cortex

are responsible for arousal and attention to input

and motivation. Histamine plays a role in arousal

and motivation, and serotonin acts to produce

decreases in arousal and sleep.

 With regard to SMD, practitioners have looked

to the relationship between optimal arousal levels

and the production of an adaptive interaction.

Thinking back to Michael, his teacher may have

been concerned about his arousal level because

he did not contribute to classroom discussions,

and she questioned whether he was processing environmental information. Kimball ( 1999 )

pointed out that moderate arousal produced an

ideal adaptive environmental interaction, but

over-arousal led to behavioral disorganization,

anxiety, and potentially negative responses. The

concept of optimal levels of arousal to function

has roots in the work of Hebb ( 1949, 1955 );

within the framework of optimal arousal, we

balance performance and enjoyment (called

hedonic tone) in our drive for homeostasis ( Kerr,

 1997 ). Although it is clear now that sensory

input to the reticular formation regulates arousal,

this relationship was less clear years ago when

original investigators proposed that stimulus

intensity was related to performance and that it

was the intensity of input that regulated arousal

level. Both of these conceptualizations identifi ed

an inverted U curve relationship between arousal

and performance and stimulus intensity. Such a

relationship is depicted in Figure 6-6 . Later work

by Berlyne ( 1960, 1971 ) expanded on this concept

to include other qualities of sensation as role

players in the modulation of arousal. He further

suggested that optimum arousal was linked to

limbic and ANS functions and that there may be

individual differences in tonic arousal levels and

“arousability.”

 Kerr ( 1990, 1997 ) proposed a more complex

relationship between arousal and performance

that depends on how each individual interprets the positive or negative tone associated

with arousal. In Kerr ’ s model, individuals are

viewed as arousal seeking or avoiding, depending on whether they fi nd increased arousal to be

a pleasant or unpleasant experience. According

to Apter ’ s ( 1984 ) reversal hypothesis, something

that had been viewed as pleasant can turn into

Brainstem

Reticular formation

Midbrain

Pons

Medulla

164 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

something unpleasant and, potentially, anxiety

provoking. Reversals may be precipitated by

an environmental stimulus, our own frustration

at not being able to perform to expectations, or

that we have simply had enough and shift from

enjoyment to boredom or fatigue ( Kerr, 1997 ).

Importantly, highly arousing tasks can be viewed

as pleasant, and high arousal does not necessarily

interfere with performance; performance is linked

with both arousal and our own interpretation of

how pleasant that arousal state is. Although Kerr

used this theory to understand performance in

sport, such a reversal hypothesis is intriguing

to consider for children with SMD who appear

to shift from under-responsive and SS/craving to

over-responsive and sensory avoiding. Again,

considering Michael, earlier accommodations for

Michael had included movement and deep pressure breaks to improve his attention and information processing. This suggests that although

Michael may appear often to have lower arousal,

movement may provide the input he needs to

reach the optimal arousal level for learning.

 Research related to the two primary dimensions associated with emotional experience,

valence and arousal, also may be useful to

consider. Valence is seen as bipolar, refl ecting

negative to positive emotion; arousal is unipolar

based on the intensity of input ( Recio, Conrad,

Hansen, & Jacobs, 2014 ). In recent research

using words with positive and negative valence

and high and low arousal effects, Recio and

colleagues found that subjects processed words

more quickly if they held a positive valence,

regardless of their arousal effect. However, the

emotional effects were strongest when extremes

of valence were combined with high arousal

input. Although this research is not specifi -

cally about sensory modulation, it suggests that

sensory input perceived as strongly positive

(high positive valence) that is highly arousing

(jumping very high on a trampoline; riding in a

fast ride; watching a fast-paced movie; receiving

a fi rm, fast rubdown with a towel) will engender

the strongest emotional response.

 Although it is well accepted that arousal is

a function of sensory input, the link to sensory

modulation is indirect. Clearly, arousal and modulation are not the same, although practitioners

have used the terms over-aroused and overresponsive interchangeably. Children who have

over-responsiveness to sensory input have a

FIGURE 6-6 Proposed relationship between arousal and performance.

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 165

serotonin (5HT), may be tied to defensiveness,

and, as such, they bear at least a cursory look.

 Serotonin is made from the amino acid precursor tryptophan, and dietary intake of tryptophan

can infl uence central levels of the transmitter.

The overall number of central 5HT neurons is

limited, but the projections are widespread; virtually all areas of the brain receive 5HT inputs

( Bear et al., 2015 ). Such widespread connections

implicate 5HT in many CNS functions and the

expression of many behaviors and disorders.

In fact, alterations in the 5HT system functions

have been linked with many psychiatric disorders

(i.e., major depression, seasonal affective disorder, obsessive-compulsive disorder) ( Jaiswal,

Mohanakumar, & Rajamma, 2015 ), as well as

ASD, schizophrenia, potential sensory impairments, and aspects of motor incoordination

( Kepser & Homberg, 2015 ). The 5HT link with

ASD is well established, such that high prenatal

and early developmental 5HT levels are associated with autistic-like behaviors (alterations in

social interaction, communication, and the presence of repetitive behavior) using animal models

( Veenstra-VanderWeele et al., 2012 ; Yang, Tan, &

Du, 2014 ). It has been diffi cult to utilize this

information in diagnosis and treatment of psychiatric disorders, however, as there is no adequate

clinical measure of 5HT activity. Furthermore,

it is important to note that multiple neurotransmitters are involved in perception and behavior.

Thus, attributing any behavioral response to sensation to a single neurotransmitter is diffi cult.

 Ongoing investigations of the 5HT system

indicate a role for serotonin in loudness dependence of auditory evoked potentials (AEP),

where loudness dependence refl ects changes in

the AEP based on the intensity of the stimulus.

Weak 5HT activity (refl ected in strong loudness dependence) has been found in individuals with psychiatric disorders noted earlier, and

it is reversed after treatment with medications

that are 5HT agonists, such as selective serotonin reuptake inhibitors (SSRIs) and lithium

( Juckel, 2015 ). Investigators suggest this and

other fi ndings implicate 5HT in auditory sensory

processing.

 Interestingly, “sensory processing sensitivity”

(SPS), considered a personality trait by Aron and

Aron ( 1997 ), has been paralleled with alterations

in the genetics of the serotonin system, specifi -

cally to the presence of a genetic variant of the

PRACTICE WISDOM

Clinical reports have suggested that, for some

children, over-responsiveness to sensory input

leads to “shutdown.” Kimball related this to

ANS changes that include cardiac irregularities,

changes in blood pressure, and a nervous system

that “cannot respond in normal ways” ( Kimball,

1976, 1977 ). More recently, Porges ( 2007 ) also

has described autonomic shutdown, refl ected

in reduced parasympathetic inhibition and

increased sympathetic activity. Although specifi c

links to sensory modulation are not available,

Kimball further suggested that reducing novel

stimuli in the environment and decreasing the

intensity and variety of input can be used as

therapeutic tools to bring arousal back to the

optimal range ( Kimball, 1999 ).

limited ability to modulate input; they also often

fi nd themselves over-aroused.

 Children who display under-responsivity to

sensory input appear to be under-aroused. For

these children, novel, intense stimuli may result

in a higher arousal level and more adaptive

environmental interaction. As with many of the

potential links between CNS function and SMD,

this area continues to warrant investigation.

Sensory Modulation and Serotonin

Neurotransmission

 There has been a move to examine the potential role of neurotransmitters in individuals with

SMD. But we should take caution: If our ability

to attach behaviors associated with SMD to specifi c CNS sites is limited, our ability to do the

same with specifi c neurotransmitter systems is

even more limited. As with anatomical structures, the study of transmitters has largely taken

place in animals. Often studies done in humans

are drug studies, suggesting that the nervous

systems under investigation were, in some way,

impaired. Understanding central neurotransmitter

function through the measurement of peripheral

references, such as transmitter metabolites in

urine, is complicated by the fact that many transmitters are also present in the periphery, and, as

such, metabolites in the urine may refl ect peripheral as well as central activity. Nonetheless,

alterations in CNS neurotransmitters, notably

166 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

serotonin transporter that infl uences 5HT actions

in the nervous system ( Homberg, Schubert,

Asan, & Aron, 2016 ). Individuals with SPS, and

those with this 5HT alteration, are more sensitive

to environmental input, and at risk for the development of emotional disorders. Homberg and

colleagues suggested that in animals with similar

variations in the 5HT system and adults with

SPS there are differences in sensory and attention networks leading to more intense sensory

processing and a higher susceptibility to overstimulation. Although the specifi c link between

SPS and alterations in the 5HT system remain

to be delineated, these investigators suggested

that study of variations in the serotonin system,

something that must utilize animal models,

may be useful to our understanding of sensory

sensitivity.

 The study of neurotransmitters is an intriguing one. They are, of course, linked with behavior. In fact, it would be safe to say they are all

linked to behaviors of some sort. The specifi city

of this linking, however, presents some diffi culty

because there are simply too many unknown

factors. Thus, further study of 5HT, the behaviors with which it is associated, and the relationship of these behaviors to SMD is needed before

sound hypotheses can be formulated.

Stress and Modulation

 One additional aspect of the relationship between

sensory modulation and the limbic system

deserves attention. Clinicians have long suspected that stress can amplify tactile or sensory

defensiveness, and recently there has been

increased research on these and related topics.

Responses to events perceived to be threatening trigger activity in complex neurobiological systems, with the goal of self-preservation.

One such system is the hypothalamic-pituitaryadrenal (HPA) system, supporting the release

of cortisol. The HPA response to stress begins

with release of corticotropin-releasing factor or

hormone (CRF or CRH) from the paraventricular nucleus (PVN) of the hypothalamus. CRH

travels to the anterior pituitary, leading to the

release of adrenocorticotropin hormone (ACTH).

ACTH, released into the circulation, travels to

the adrenal cortex and leads to the release of cortisol ( Bear et al., 2015 ). This response to stress

requires a few minutes of time. Cortisol release

is self-limiting in a typical nervous system; once

released, it helps the body mount a fi ght-or-fl ight

response to the stressor, but it also inhibits the

release of CRH. Often cortisol levels in blood or

saliva are measured as a means of quantifying

physiological response to a stressor.

 The other system linked with the stress

response is the SNS. It too is mediated by outputs

from the periventricular region of the hypothalamus. SNS responses to stress result in increases

in heart rate and blood pressure, the release of

glucose, and decreased blood fl ow to the gut.

These responses rely on the activity of epinephrine and norepinephrine in the periphery, and

they are paralleled by norepinephrine responses

centrally. Central release of norepinephrine

comes from a brainstem nucleus, the locus coeruleus, and supports increased arousal, focused

attention, and increased vigilance ( Gunnar &

Quevedo, 2007 ), all designed to support the

fi ght, fl ight, or fl ee response to the stressor.

 These stress response systems involve limbiccortical circuits, including the amygdala, hippocampus, and areas of the prefrontal cortex ( Gray

& Bingaman, 1996 ; Gunnar & Quevedo, 2007 ).

 Gunnar and Quevedo ( 2007 ) indicated that the

amygdala is of particular importance in the regulation of CRH, and the prefrontal cortex in

conjunction with the hippocampus play a role in

analysis of the stressor and threat appraisal.

 Activation of the anxiety system, similar

to Gray ’ s behavioral inhibition system (1982) ,

results in avoidance behaviors. The anxiety

system is put into action when the expectation of

an event is negative. Thus, in any situation, we

all have certain expectations of what will occur.

We expect a hug from a friend to feel good and

a shot to be only slightly painful. If the friendly

hug turns into an uncomfortable squeeze or the

injection has a burning quality not previously

experienced, then our expectation does not match

the real situation, and we fi nd ourselves with

increased arousal and anxiety. Gray stated that if

a match occurred between expected and actual

input, the behavioral inhibition system was not

activated and general behavior was not altered.

If a mismatch occurred, the behavioral inhibition

system was activated and took control of behavior, leading to increased arousal and attention to

incoming stimuli, often producing anxiety. This

system has been linked with serotonin function

and activity in the septohippocampal region

( Gray, 1987 ).

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 167

 If one accepts the concept of limbic involvement in sensory modulation, then stress behaviors may play a role in the manifestation of

sensory over-responsiveness. When incoming

and expected inputs are mismatched, Gray ’ s

behavioral inhibition system takes over, leading

to increased arousal and attention to the sensory

stimuli, perhaps resulting in a defensive response.

These concepts of sensory modulation remain

hypothetical, however, and require considerably

more study.

HERE ’ S THE POINT

• The limbic system functions to support the

intake and processing of sensation, as well as

in the attachment of emotional signifi cance

and memory to sensation. Dysfunction

in limbic processing has been linked with

increased sensory responsivity, aggression, and

emotionality.

• The reticular system mediates arousal level and

is dependent on sensory input to accomplish

this role. Optimal arousal is task-dependent

and may be infl uenced by stimulus intensity.

• Sensory “shutdown” may refl ect reduced

parasympathetic and increased SNS activity in

response to an overwhelming environment.

• Alterations in aspects of serotonin system

function have been of interest to scientists

investigating sensory sensitivity.

• Stress may moderate behavioral responses to

environmental stimuli but additional research is

needed to fully understand this relationship.

Sensory Modulation Disorders

 As noted earlier, sensory modulation disorders

can be seen across different sensory systems

and are manifested in varied ways. Here we will

focus on those more commonly recognized modulation disorders within the somatosensory and

vestibular systems (refer to Chapter 4 , Structure

and Function of the Sensory Systems). We look

briefl y at other sensory systems as well, acknowledging that less is known about these disorders.

 The focus in this section is on children whose

primary concern is that of sensory modulation.

Although modulation disorders have been identifi ed in conjunction with disorders such as

ASD and ADHD, they have importantly been

documented in children without other diagnoses. The work of Reynolds and Lane ( 2008 );

 van Hulle, Schmidt, and Goldsmith (2012) ; and

 Miller and colleagues ( 2012 ) support this. Reynolds and Lane documented three distinct cases

of children with SOR and no additional diagnosis, and van Hulle and colleagues indicated that

more than 50% of children with SOR in their

study ( n = 970) failed to meet criteria for other

recognized childhood psychiatric diagnoses. The

work of Miller and colleagues also indicated that

although there is considerable overlap between

children with ADHD and children with SMD,

there are clear differences in sensory responsivity, both behaviorally and physiologically, as well

as on measures refl ecting emotion and attention.

We will return to the coexistence of modulation

disorders with ASD and ADHD at the end of this

section.

Tactile Defensiveness

 Considering potential links to CNS structures

and functions, we now look at modulation dysfunction that has been associated with specifi c

sensory systems. In this section, we present

information on both observable behaviors and

suggested neurophysiological links. The earliest

identifi ed, and most often discussed, is tactile

defensiveness. In 1964, Ayres proposed a “provisional theory,” based in part on earlier observations of Head ( 1920 ), to explain a clinical

syndrome composed of defi cits in tactile defensiveness, distractibility, and increased level of

activity. Expanding on these ideas, Ayres ( 1972 )

described the two tactile systems as a continuum

rather than a strict dichotomy. They interacted “to

provide a continuum of information and response

with a need-for-defense interpretation and reaction at one end of the continuum and a discriminative interpretation and discrete response at

the other end” (p. 214; Fig. 6-7 ). Ayres hypothesized that tactile defensiveness was the result

of an imbalance between discriminative interpretation and need for defense. She generalized

from a protopathic-epicritic continuum to an

anterolateral-dorsal column continuum ( Ayres,

 1964, 1972 ). According to Ayres ( 1972 ), tactile

defensiveness occurred when the discriminative

dorsal column medial lemniscal (DCML) system

failed to exert its normal inhibitory infl uence over

the anterolateral system. Therefore, light touch

168 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

evoked protective, escape-like behavior and

strong emotional responses. She hypothesized:

 The tactile defensive response, and other

defensive responses to nociceptive qualities

in sensory stimuli, represents an insuffi cient

amount of the inhibitory component in a functional system designed to monitor a certain

type of impulse control. Thus, the behavioral

response system designed for protection and

survival predominated over a system designed

to allow the organism to respond to the spatial

temporal qualities of the tactile stimuli. ( Ayres,

 1972 , p. 215)

 Ayres ( 1964 ) also suggested that adrenaline

(epinephrine), released from the SNS during

stress, played a role in the behavioral manifestations of tactile defensiveness in that the reticular activating system was sensitive to the effects

of adrenaline and the DCML pathway was not.

Ayres theorized that anxiety was both a cause and

an effect of the predominance of the protective

system and that the problem was self-perpetuating.

Furthermore, a child chronically controlled by the

protective system would be offered little opportunity for appropriate environmental exploration,

and this might lead to delays in perceptualmotor development.

 As early as 1972, Ayres recognized that the

gate control theory of Melzack and Wall ( 1965 )

“unifi ed” various historical perspectives on the

duality of the tactile system. She proposed that

the gate control theory provided a conceptual

model for tactile defensiveness. Briefl y stated,

this theory suggested that “gate” neurons present

in the substantia gelatinosa of the spinal cord

controlled the passage of impulses to the CNS.

Control of these gate cells was infl uenced both by

incoming tactile inputs and by cortical infl uences

( Fig. 6-8 ). Tactile inputs carried in large A-beta

fi bers commonly associated with touch-pressure

and other inputs mediated by the DCML pathway

activated the gate cells, which, in turn, prevented

the transmission of pain to the CNS.

 In contrast, inputs mediated by small A-delta

and C (pain) fi bers inhibited the gate cell. Thus,

because the “gate is open” when the gate cell

is inhibited, transmission of pain impulses was

permitted. Importantly, cortical infl uences, such

as anxiety, attention, and anticipation, as well

as sensory input regarding other channels, also

mediate gated activity. All of these played a role

in determining whether the gate cell was activated (gate closed) or inhibited (gate opened)

and, therefore, whether pain transmission could

proceed ( Melzack & Wall, 1965 ).

 Ayres ( 1972 ) believed that the provision of

specifi c (discriminative) tactile and proprioceptive stimuli would activate the DCML system to

“close the gating mechanism” so as to block the

protective response to touch and diminish associated increased levels of activity and distractibility. Moreover, she believed that tactile stimuli that

elicited a defensive response inhibited the gate

cell, thereby permitting transmission of stimuli

to the CNS and resulting in a defensive response.

Deep touch-pressure and other sensations mediated by the dorsal column seemed to result in

gate cell activation, decreasing transmission of

defense-eliciting stimuli and, thereby, diminishing the defensive response. These hypotheses

also explained the ability of previous stimuli,

moods, and so forth, to infl uence the responses

of a child with tactile defensiveness. These

factors would be a component of the descending

cortical infl uences on the gate, whereby stressful

states, for example, might result in gate cell inhibition and, thus, permit transmission of defenseeliciting stimuli.

 Unfortunately, some aspects of the gate control

theory have not been confi rmed by research, and

others are poorly understood and controversial.

For instance, no actual gate neurons have been

found in the spinal cord, and the mechanism of

action of large afferent fi bers infl uencing pain

transmission and central mediation of pain has

been shown to be different ( Moayedi & Davis,

FIGURE 6-7 Ayres proposed that the protopathic (anterolateral) pathways and epicritic (discriminative) pathways

functioned as a continuum. When we perceive touch as a threat, it activates our protective responses, such as

withdrawal or aggression. As our perception of touch moves from threat toward neutral and beyond, we can

use touch to explore the environment.

Threat; activation of

“protopathic” system,

defensive response

Neutral

Salient; activation of

the “epicritic” system,

seek more information

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 169

FIGURE 6-8 In their gate control theory, Melzack and Wall proposed that gate neurons in the spinal cord

mediated the transmission of pain impulses to the brain. It was thought that the gate neurons were infl uenced

by incoming touch or higher brain regions. Spinal level gate neurons have not been identifi ed, but this theory is

still foundational for our understanding of pain transmission.

 2013 ). However, descending central pain controls exist, and it is likely that stimulation of the

dorsal column will lead to pain relief ( Moayedi &

Davis, 2013 ).

 In 1983, Fisher and Dunn published a review

of pain control theories, including perspectives

on the gate control theory of Melzack and Wall

 ( 1965 ) and evidence of inhibitory pain pathways.

An important contribution of Fisher and Dunn

 ( 1983 ) was the recognition that the reduction

of tactile defensiveness would not lead to improved tactile discrimination. Rather, they

stressed that tactile defensiveness and poor tactile discrimination were separate disorders of

tactile processing and not two ends of the same

continuum; both tactile defensiveness and poor

tactile discrimination could, and often did, occur

in isolation ( Fisher & Dunn, 1983 ).

 One year earlier, Larson ( 1982 ) had hypothesized that tactile defensiveness was the result

of a fi ltering defi cit resulting from too little

inhibition. She explained the high arousal, distractibility, and defensiveness observed in children with tactile defensiveness by a lack of

inhibition of irrelevant input. Fisher and Dunn

 ( 1983 ) subsequently suggested that the application of the phrase “lack of inhibition” to the

child with tactile defensiveness was appropriate

in describing the failure of higher CNS structures to modulate incoming tactile stimuli. They

pointed out that “clinical descriptions of ‘lack of

inhibition’ in children who display [tactile defensiveness] seem to be compatible with the concept

that higher-level infl uences are not adequately

modulating tactile inputs” (p. 2). Thus, they

advocated the use of intervention to decrease

arousal, including touch-pressure, proprioception, and linear vestibular stimulation.

 Although Larson ( 1982 ) and Fisher and Dunn

 ( 1983 ) limited themselves to discussions of children with tactile defensiveness, their arguments

could readily be applied to children with other

Pain signals sent along

acute and chronic pain fibers.

Pain signals are still sent via

acute and chronic pain.

Rubbing the injury

sends messages

along touch

and pressure.

The gate in spinal cord

is closed, so no pain messages

get through to the brain.

The gate in spinal cord

is open, so pain messages

get through to the brain.

Messages from

touch and pressure

activate the gating

nerve cell in

the spinal cord.

170 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

manifestations of sensory defensiveness. Further,

although Larson ( 1982 ) emphasized a lack of

inhibition resulting in tactile defensiveness, she

actually described an imbalance in descending

mechanisms, resulting in either too little or too

much inhibition. “This imbalance decreases the

ability to perceive incoming stimuli from tactile

and other sensory modalities [italics added]”

( Larson, 1982 , p. 592).

 A great deal of research on SOR has taken

place since these initial hypotheses were put

forward; much of this is summarized in Chapter 16

(Advances in Sensory Integration Research: Basic

Science Research). The work of Mary Schneider

and colleagues ( 2009 ) provided a causal link

between prenatal stress and tactile defensiveness

in a primate model and linked tactile defensiveness to altered striatal dopamine activity. This

link was supported in human research conducted

by Keuler and colleagues ( 2011 ). These same

investigators found that tactile and auditory

over-responsivity (defensiveness) was heritable,

infl uenced by prenatal environment, and correlated with negative affect and fear.

 Defi cits in tactile modulation have been identifi ed in children with ADHD and children with

ASD. In children with ADHD, Parush and colleagues ( 2007 ) demonstrated that tactile defensiveness was distinguishable from poor tactile

discrimination relative to central processing

mechanisms. This work is important for its contribution to our understanding of defensive and

discriminatory mechanisms and for the support it

provides for the hypothesis of altered neural inhibition put forward by Fisher and Dunn ( 1983 ). In

children with ASD, sensory modulation differences have been noted generally, and tactile and

auditory over-responsivity are commonly identifi ed when individual sensory systems are examined ( Tomchek & Dunn, 2007 ).

 Tactile defensiveness is a problem, in large

part, because of inappropriate behaviors that

accompany it. Tactile defensiveness may be

identifi ed by a meaningful collection of behaviors, such as:

• Avoidance of touch

 • Avoidance of certain styles or textures

(e.g., scratchy or rough) of clothing or,

conversely, an unusual preference for

certain styles or textures of clothing (e.g.,

soft materials, long pants, or sleeves)

 • Preference for standing at the end of a line

to avoid contact with others

 • Tendency to pull away from anticipated

touch or from interactions involving

touch, including avoidance of touch to

the face

 • Avoidance of play activities that involve

body contact, sometimes manifested by a

tendency to prefer solitary play

• Aversive responses to non-noxious touch

 • Aversion or struggle when picked up,

hugged, or cuddled

 • Aversion to certain daily living tasks,

including baths or showers, cutting of

fi ngernails, haircuts, and face washing

 • Aversion to dental care

 • Aversion to art materials, including

avoidance of fi nger paints, paste, or sand

• Atypical affective responses to non-noxious

tactile stimuli

 • Responding with aggression to light touch

to arms, face, or legs

 • Increased stress in response to being

physically close to people

• Objection, withdrawal, or negative responses

to touch contact, including that encountered

in the context of intimate relationships

( Royeen & Lane, 1991 , p. 112)

 As can be discerned from this list, defensiveness

to touch potentially interferes with all occupations and roles. When a child limits food and

clothing choices and resists activities, such as

face and hair washing and nail clipping, basic

self-care becomes a trying ordeal. Avoiding

sand, refusing to walk barefoot on the grass, or

needing to control play activities can negatively

affect one ’ s role as a peer or sibling player. Even

the more subtle behaviors that we noted with

Michael, seeming to be very quiet and not engaging with others in the classroom, impair occupational engagement and performance. These and

other behaviors may disrupt classroom behavior,

making learning diffi cult.

 Beyond behaviors that are linked easily to

defensive responses to touch are those that are

secondary to the need to control the sensory

environment. Often children with defensiveness

to touch are seen as distractible and overly active

as they respond to irrelevant incoming sensory

input ( Ayres, 1965, 1966, 1969 ; Bauer, 1977 ).

It is important to note that several investigators

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 171

have indicated that although over-responsivity

to touch may overlap with these characteristics

of attention defi cit, the two disorders are distinct

(S. J. Lane, Reynolds, & Thacker, 2010 ; Mangeot

et al., 2001 ; Miller et al., 2012 ; Reynolds

et al., 2009 ). Furthermore, Wilbarger and Royeen

 ( 1987 ) speculated that tactile defensiveness could

be a predisposing factor for irregular emotional

tone, lability, extreme need for personal space,

and disruption in personal care. Scardina ( 1986 )

hypothesized that tactile defensiveness interfered

with the ability to establish or maintain intimate

relationships. Thus, a child or adult with tactile

defensiveness may experience a myriad of secondary defi cits.

 Identifi cation of tactile defensiveness is possible by looking for a meaningful cluster of behaviors, many of which were listed earlier. Many

children dislike having their face washed and

nails trimmed. These behaviors alone do not constitute tactile defensiveness. As with all disorders

of sensory integration, the identifi cation of tactile

defensiveness is based on the presence of a consistent pattern (i.e., a suffi cient number of aversive or negative reactions to touch) to confi rm

that it is, indeed, the response to touch that provides the basis of the reaction. This is particularly important when we consider the affective

or emotional overlay that may occur with tactile

defensiveness.

Aversive Responses to Vestibular

and Proprioceptive Inputs,

Gravitational Insecurity,

and Vestibular and Proprioceptive

Under-Responsiveness

 Poor modulation within the vestibular system

also has been identifi ed. The vestibular system

is thought to be a primary organizer of sensory

information ( Ayres, 1972, 1978, 1979 ). The vestibular system coordinates movement of the body

and eyes in response to environmental demand; it

is responsible for awareness of position in space,

provides a stable visual fi eld, and contributes

to physical and emotional security. According

to Ayres, our relationship with gravity is more

essential to our well-being than is our relationship with our mother (1979).

 Fisher and Bundy ( 1989 ) indicated that

over-responsivity to vestibular and proprioceptive sensations may be manifested in two ways:

Aversive responses to vestibular-proprioceptive

inputs are characterized by nausea, vomiting, dizziness or vertigo, and other feelings of discomfort associated with autonomic (sympathetic)

nervous system stimulation. Gravitational insecurity is characterized by excessive emotional

reactions or fear that is out of proportion to the real

threat or actual danger arising from vestibularproprioceptive stimuli or position of the body

in space. Although neither disorder is well

understood, both are hypothesized to be a result

of hyperresponsiveness or poor modulation

of vestibular-proprioceptive inputs ( Fisher &

Bundy, 1989 ), and there is some evidence that

increased sensitivity to vestibular stimulation or

visual-vestibular confl ict can result in motion

sickness ( Baloh & Honrubia, 1979 ) [italics

added] (p. 92).

 Grounded in the work of Ayres and Fisher

and Bundy, May-Benson and Koomar (2007)

indicated that gravitational insecurity could be

linked to inadequate vestibulocerebellar interactions and potentially decreased vestibularocular integration, leading to increased arousal

and fear responses to unexpected movement

experiences. Children with gravitational insecurity fear generic, everyday movement experiences, slow or fast, particularly those that involve

head movements out of the vertical. Clinicians

report that children with gravitational insecurity

perceive small movements to be larger than they

are. Children with this disorder may avoid activities that require new body or head positions,

especially when their feet cannot be in contact

with the fl oor. Fisher ( 1991 ) suggested that gravitational insecurity was related to an inability to

resolve sensory confl ict and inadequate development of body scheme. Because children with

this modulation disorder seem to misjudge the

amount of head movement they are experiencing, it also may be that gravitational insecurity is

a problem of discrimination within this system.

An alternative explanation has been suggested to

be ineffi cient proprioceptive processing because

proprioception has been said to modulate vestibular inputs ( Ayres, 1979 ). The fear caused by

gravitational insecurity is basic and profound

and can affect emotional and behavioral development. Seemingly simple tasks, such as getting

into and out of a car or stepping down off a curb,

present anxious moments for individuals with

gravitational insecurity. Of particular concern

for these individuals is backward space, and, as

172 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

such, they avoid activities such as swinging on

swings.

 Aversive responses to, or intolerance of,

movement is the reaction we feel when we

become car-, plane-, or seasick. It is characterized by strong feelings of discomfort, nausea,

vomiting, or dizziness after movement that activates the semicircular canals (i.e., angular acceleration). This disorder may result from faulty

modulation of inputs to the semicircular canal.

Alternatively, aversive reactions to movement

may result from an inability to resolve sensory

confl ict among visual, vestibular, and proprioceptive inputs ( Fisher, 1991 ).

 Aversive responses to movement may not

appear during or even directly after an activity.

Children showing aversive responses to movement may have diffi culty interpreting the sensory

input and may respond several hours later with

a negative reaction. Fisher and Bundy ( 1989 )

and Fisher (unpublished data) described an individual with whom they had carried out an indepth interview and vestibular testing. She was

described as experiencing “sensory overload” or

“sensory disorientation” after a period of visualvestibular stimulation that included visualvestibular confl ict. Fisher ( 1991 ) described this

client ’ s response as follows:

 Approximately 3 hours after stimulation, the

subject began to experience the feeling that her

head, arms, and legs had become detached from

her body and were fl oating in space. When she

attempted to walk on a level surface, she felt

as if she were walking on an uneven, unpredictable surface. Sometimes the surface would

seem to be higher than she expected it to be,

and sometimes the ground would be lower than

she expected it to be. (p. 90)

 Thus, an inability to resolve movement, proprioception, and visual input had a strongly disruptive effect on this individual ’ s internal body

scheme. Under-responsivity to movement is

seen in children such as Michael, in this case,

in conjunction with under-responsivity to proprioception. Michael seeks activities that provide

movement and proprioceptive sensations in order

to obtain what he considers to be an optimal

level of arousal and attention in the classroom

and at home.

 Clinicians have debated the existence of

an SMD related strictly to proprioception that

appears to resemble under-responsiveness in

that it is characterized by behaviors designed

to obtain a great deal of proprioceptive input

( Blanche & Schaff, 2001 ). Thus, children may

hit, bang, bump, or fall on purpose. They may

appear very aggressive in their interactions, and

their movements may seem clumsy. Blanche and

colleagues developed and pilot-tested an observation tool for proprioceptive functions intended

to be used with other clinical observations of proprioceptive function (the Comprehensive Observation of Proprioception, Blanche, Bodison,

Chang, & Reinoso, 2012 ). Using an exploratory

factor analysis, they identifi ed four proprioceptive factors (muscle tone and joint stability,

proprioceptive seeking, postural control, motor

planning); the seeking provides initial support

for the suggestion that proprioceptive modulation defi cits exist. Whether this is a specifi c disorder or a refl ection of other sensory integrative

problems continues to require further clinical and

empirical investigation.

 Vestibular and proprioceptive modulation

defi cits have the potential to interfere with occupational performance in many ways. When children show over-responsivity to vestibular input,

they generally avoid many types of movement.

Fearing movement through space, infants and

toddlers engage in diminished environmental

exploration and gross motor activity. As preschoolers, children with vestibular modulation

defi cits may become tense and anxious on playground equipment, avoid rough and tumble play,

or become easily nauseated when riding in a

vehicle. School-age children may avoid amusement parks, camp activities, and sports. Vestibular and proprioceptive modulation defi cits may

lead to a poor sense of position in space and

movement through space and result in behaviors

such as pushing, crashing, and falling.

Sensory Modulation Dysfunction

in Other Sensory Systems

 In addition to these somewhat classic examples

of specifi c SMD that have been under study for

several years, behavioral and physiological evidence has documented auditory modulation defi -

cits ( Chang et al., 2010 ), and clinical evidence

has suggested that over-responsiveness may be

a factor in the visual system as well. Children

with auditory modulation disorders may cover

their ears when in the cafeteria or grocery store,

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 173

where sound bounces off of hard surfaces. They

might also have diffi culty paying attention to

the teacher or their seat work if they have overresponsiveness to a busy visual environment.

Many clinicians document taste and smell sensitivity, and it has clearly been identifi ed by some

investigators in children with autism (e.g., A. E.

 Lane, Molloy, & Bishop, 2014 ). Observations of

a broader construct of sensory modulation disorder would be very consistent with the work

of McIntosh, Miller, Shyu, & Hagerman ( 1999 )

and fi t well with the concept of a general SMD.

Careful documentation of behaviors that appear

to refl ect modulation defi cits in these sensory

systems—and examination of the underlying

neuroscience correlates of the behaviors—is

needed. Suggestions for intervention with clients

who have SMD can be found in Chapter 12 (The

Art of Therapy), Chapter 13 (The Science of

Intervention: Creating Direct Intervention from

Theory), and Chapter 14 (Distilling Sensory

Integration Theory for Use: Making Sense of

the Complexity), where the art and science of

intervention are presented along with different

models for treatment.

Sensory Modulation Disorder

in Children with Additional Diagnoses

 Sensory modulation has been identifi ed as a

“stand-alone” disorder, but also it has been linked

with other neurodevelopmental disorders, such

as ASD and ADHD. Investigators have examined

sensory modulation in conjunction with behavior and participation, stress responses, and ANS

responses to sensation in children with ASD

and ADHD. We will look briefl y at the research

along these lines, and more information can be

found in Chapter 16 (Advances in Sensory Integration Research: Basic Science Research).

Autism Spectrum Disorder

 Sensory modulation in children with ASD

is complex, with reports of both over- and

under-responsivity. The Sensory Profi le (SP) and

the Short Sensory Profi le (SSP) have been used

most commonly to identify sensory modulation

disorders; the SP provided the fi rst formalized

identifi cation of sensory modulation disorders

in children with ASD ( Kientz & Dunn, 1997 ).

Although this initial work did not show a link

with severity of autism, later work by several

investigators ( Baranek, David, Poe, Stone, &

Watson, 2006 ; Ben-Sasson et al., 2008 ; Kern

et al., 2007 ; A. E. Lane et al., 2014 ; Watson

et al., 2011 ) has indicated that differences in

sensory modulation do correlate with autism

severity and, in some studies, with mental age

( Baranek et al., 2006 ; Leekam, Nieto, Libby,

Wing, & Gould, 2007 ).

 Links between inadequate sensory modulation

and stress responses also have been established.

Children with ASD were noted to show reduced

SNS responses to sensory challenge along with

behavioral and emotional over-responsivity

( Schoen, Miller, Brett-Green, & Nielsen, 2009 ).

Later work suggested two response patterns: a

high level of tonic SNS activity coupled with

high responsivity to sensory challenge, and lower

SNS activity coupled with lower responses to

sensory challenge ( Schoen, Miller, Brett-Green,

Reynolds, & Lane, 2008 ). Further, SOR has been

linked with anxiety in toddlers with ASD ( Green,

Ben-Sasson, Soto, & Carter, 2012 ). The complexity of this link in ASD is emphasized by Corbett,

Schupp, Levine, and Mendoza ( 2009 ) with the

fi nding that some aspects of sensory processing

associate with elevated morning cortisol whereas

others associate with lower morning cortisol.

 There is some indication that differences in

sensory processing in children with ASD may

show specifi c characteristic patterns. Patterns on

the SP are different for children with ASD compared with children with ADHD and to children

developing typically ( Ermer & Dunn, 1998 ).

Tactile and taste or smell over-responsivity has

been documented ( Wiggins et al., 2009 ) and

linked with stereotyped behaviors. Ausderau

and colleagues ( 2014 ) also identifi ed a range of

sensory subtypes, linking them with child characteristics (i.e., gender, age factors, and autism

severity) and family characteristics. Lane and

colleagues (Lane et al., 2010) have worked to

develop a typology that more fully characterizes

sensory modulation defi cits in children with ASD.

Their most recent work examined SP scores along

with verbal IQ, autism severity, age, and gender.

Through this study, they identifi ed four sensory

clusters: sensory adaptive, refl ecting children with

no clear sensory modulation defi cits; taste/smell

sensitive, refl ecting extreme taste or smell sensitivity, with poor auditory fi ltering and sensoryseeking or under-responsive behaviors; postural

inattentive, refl ecting extreme scores for the low

174 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

energy weak items, with poor auditory fi ltering and SS or under-responsivity; and general

sensory modulation defi cits, which included

movement sensitivity ( Lane, Molloy, & Bishop,

 2014 ). Interestingly, in this study they also found

a relatively large proportion (37%) of children in

the sensory adaptive group, indicating no clear

modulation defi cits. This fi nding differs from

those of others (c.f. Tomchek & Dunn, 2007 ),

indicating that up to 92% of children with ASD

may have concomitant sensory modulation defi -

cits. Lane and colleagues suggested this may be

the result of differences in sampling.

 Sensory modulation differences in children

with ASD also have been linked with aspects of

function, although the relationships continue to

need clarifi cation. Baker and colleagues ( Baker,

Lane, Angley, & Young, 2008 ) suggested there

were relationships between maladaptive and emotional or behavioral problems and the SSP patterns of under-responsivity or seeking, auditory

fi ltering, and low energy/weak. Similarly, poor

academic, behavioral, and emotional performance

have been linked with sensitivity to touch, auditory fi ltering diffi culty, and under-responsivity or

seeking ( Ashburner, Ziviani, & Rodger, 2008 ).

Sensory avoiding, a quadrant in the Dunn model,

interferes with occupational engagement and participation ( Little, Sideris, Ausderau, & Baranek,

 2014 ). Ben-Sasson and colleagues ( 2008 ) took

a somewhat different approach with young children with ASD and found three broad groups of

children: those with a low frequency of behaviors indicative of poor sensory modulation on the

Sensory Profi le, those with mixed frequency, and

those with high frequency of behaviors indicative

of poor sensory modulation; negative emotions,

anxiety, and depressive symptoms were found

more commonly in the high frequency group,

whether the sensory response patterns indicated

over- or under-responsivity. Recent work with

preschool-aged children with ASD uncovered a

strong link between sensory processing patterns

and receptive and expressive language. In this

study ( Tomchek, Little, & Dunn, 2015 ), when

children showed less auditory or visual sensitivity and characteristics consistent with the

low energy/weak category, they had increased

language skills; children with hypo-responsivity

and taste or smell sensitivity also had decreased

language skills. Sensory-seeking distractibility

interfered with social behavior as well as fi ne and

gross motor skills; adaptive behavior was negatively impacted by tactile and movement sensitivity, taste and smell sensitivity, and SS.

 Baranek, Boyd, Poe, David, and Watson

 ( 2007 ) developed a performance tool to identify sensory modulation disorder, suggesting that

parent report tools may be insuffi cient. Using

their tool, they investigated sensory sensitivities in children with ASD, as well as other disorders, fi nding that SOR appears to be linked

with mental age for children with ASD as well

as with more general developmental delay. These

investigators also identifi ed sensory underresponsiveness to auditory input in their study

group. Under-responsiveness was substantiated

in children with ASD ( Ben-Sasson et al., 2009 )

and, for some children, found to coexist with

SOR ( Ben-Sasson et al., 2007 ; Lane, Reynolds,

& Thacker, 2010 ).

Attention Defi cit-Hyperactivity Disorder

 Sensory modulation has been documented in

children with ADHD, with initial studies indicating that there were fairly global sensory differences between children with ADHD and children

developing typically ( Dunn & Bennett, 2002 ;

 Miller, Nielsen, & Schoen, 2012 ; Yochman,

Parush, & Ornoy, 2004 ). Although children

with ADHD were characterized as having diffi -

culty processing auditory, tactile, emotional, and

behavioral information related to sensation and

showing SS, along with diffi culty with adaptive

responses to sensation, emotional reactivity, and

inattention or distractibility, a systematic review

indicated that there was insuffi cient evidence for

clear subtypes ( Ghanizadeh, 2011 ). The defi cits

in sensory modulation have been shown to be

related to behavioral concerns. Similar fi ndings

were reported by Shimizu, Bueno, and Miranda

 ( 2014 ) in a Brazilian sample.

 SOR has been noted in some children with

ADHD, and it may play a role in teasing apart

features of this disorder ( Mangeot et al., 2001 ;

 Reynolds, Lane, & Gennings, 2009 ). Children

with both ADHD and SOR (ADHD + SOR) show

greater anxiety than either children developing

typically or children with ADHD but no SOR

(ADHD-SOR). They demonstrate higher cortisol

responses and ineffi cient SNS recovery following sensory challenge (S. J. Lane, Reynolds, &

Thacker, 2010 ; Reynolds et al., 2009 ). Looking

somewhat more broadly, children with ADHD

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 175

and SMD also differ from children developing

typically and children without SMD on measures

of SNS function, somatic complaints, adaptability, and aspects of anxiety or depression ( Miller

et al., 2012 ).

HERE ’ S THE POINT

• Ayres likened the neural processes underlying

tactile defensiveness to those defi ned by

Melzack and Wall, relative to the gate control

theory of pain. Although the spinal level

gate neuron has not been identifi ed, there is

evidence for descending pain control elicited by

deep pressure input.

• Many behaviors linked with tactile

defensiveness reflect the need to control the

environment.

• Gravitational insecurity (GI) and aversiveness to

movement refl ect different modulation defi cits

within the vestibular system. GI is seen as fear

of movement and fear of moving the head

out of upright; aversiveness to movement is an

intolerance to movement.

• Poor proprioceptive modulation has been

less well defi ned but some research supports

proprioceptive seeking as a possible modulation

concern.

• Sensory modulation defi cits are well established

in children with autism, with indicators

supporting different subtypes or subcategories.

Research indicates that one subgroup of

children with autism shows adaptive or typical

sensory modulation, whereas other subgroups

continue to be refi ned.

• Some children with ADHD demonstrate sensory

modulation defi cits, reflected in SOR as well

as SS. When SOR is identifi ed in this group of

children, it has been linked to anxiety.

Summary and Conclusions

 In summary, SMD is complex and multidimensional, and yet our knowledge has grown regarding this disorder through the past several years.

When any sensory input is not modulated in an

expected way, the behavior that results is “out

of step” with what is needed for an adaptive

environmental interaction. For some children,

disorders of modulation are linked to disruptive

behaviors, whereas for others, such as Michael,

who was presented at the beginning of the

chapter, SMD is paralleled by withdrawal and

poor registration. Poor modulation has ramifi -

cations, both within the nervous system (e.g.,

affecting attention, arousal, and modulation of

other inputs) and in the outside world because

it results in the production of behaviors that do

not match environmental demand or expectation. Research has provided suffi cient information that we know modulation disorders exist in

the absence of other comorbidities, but also in

addition to diagnoses such as ASD and ADHD.

Although researchers continue to unravel the

neural links that underlie poor modulation, more

needs to be done in this area.

Where Can I Find More?

 Sensory modulation, and its impact on participation and occupation, have been studied by many

investigators. Looking for additional information on the impact of disorders of modulation

is perhaps best served by identifying the area of

occupation about which there is concern. Here

are some recent examples. Please note this is far

from an all-inclusive list!

Child Participation

 Mische-Lawson, L., Foster, L., Lawson, L. M., &

Foster, L. (2016). Sensory patterns, obesity and

physical activity participation of children with

autism spectrum disorder. American Journal

of Occupational Therapy, 70 (1), 7005180070.

doi:10.1111/j.1467-7687.2009.00882.x.Better

 Piller, A., & Pfeiffer, B. (2016). The Sensory

Environment and Participation of Preschool

Children with Autism Spectrum Disorder.

Occupational Therapy Journal of Research

(Thorofare NJ), 36 (3), 103–111. doi:10.1177/

1539449216665116

Parent Participation

 DaLomba, E., Baxter, M. F., Fingerhut, P., &

O’Donnell, A. (2017). The effects of sensory

processing and behavior of toddlers on parent

participation: A pilot study. Journal of Occupational Therapy, Schools, & Early Intervention, 10 (1), 27–39. doi:10.1080/19411243.20

16.1257968

 Toileting

 Bellefeuille, I. B., Schaaf, R. C., Polo, E. R.,

Beadury, I., Schaaf, R. C., & Ramos, E. (2013).

176 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

Occupational therapy based on Ayres Sensory

Integration in the treatment of retentive fecal

incontinence in a 3-year-old boy. American

Journal of Occupational Therapy, 67 (5), 601–

606. doi:10.5014/ajot.2013.008086

 Eating

 Engel-Yeger, B., Hardal-Nasser, R., & Gal, E.

(2016). The relationship between sensory processing disorders and eating problems among

children with intellectual developmental defi -

cits. British Journal of Occupational Therapy,

79 (1), 17–25. doi:10.1177/0308022615586418

 References

 Apter , M. J. ( 1984 ). Reversal theory and personality:

A review . Journal of Research in Personality , 18 ,

 265 – 288 .

 Aron , E. N. , & Aron , A. ( 1997 ). Sensory-processing

sensitivity and its relation to introversion and

emotionality . Journal of Personality and Social

Psychology , 72 ( 2 ), 345 – 368 .

 Ashburner , J. , Ziviani , J. , & Rodger , S. ( 2008 ).

 Sensory processing and classroom emotional,

behavioral, and educational outcomes in children

with autism spectrum disorder . American

Journal of Occupational Therapy , 62 , 564 – 573 .

 doi:10.5014/ajot.62.5.564

 Ausderau , K. K. , Furlong , M. , Sideris , J. , Bulluck ,

 J. , Little , L. M. , Watson , L. R. , . . . Baranek ,

 G. T. ( 2014 ). Sensory subtypes in children

with autism spectrum disorder: Latent profi le

transition analysis using a national survey of

sensory features. Journal of Child Psychology and

Psychiatry , 55 , 935 – 944 . doi:10.1111/jcpp.12219

 Ayres , A. J. ( 1964 ). Tactile functions: Their relations

to hyperactive and perceptual motor behavior .

American Journal of Occupational Therapy , 18 ,

 6 – 11 .

 Ayres , A. J. ( 1965 ). Patterns of perceptual-motor

dysfunction in children: A factor analytic study .

Perceptual and Motor Skills , 20 , 335 – 368 .

 Ayres , A. J. ( 1966 ). Interrelationships among

perceptual-motor functions in children. American

Journal of Occupational Therapy , 20 , 288 – 292 .

 Ayres , A. J. ( 1969 ). Defi cits in sensory integration

in educationally handicapped children. Journal of

Learning Disabilities , 2 , 160 – 168 .

 Ayres , A. J. ( 1972 ). Sensory integration and

learning disorders . Los Angeles, CA : Western

Psychological Services.

 Ayres , A. J. ( 1978 ). Learning disabilities and

the vestibular system. Journal of Learning

Disabilities , 11 , 18 – 29 .

 Ayres , A. J. ( 1979 ). Sensory integration and the child .

 Los Angeles, CA : Western Psychological Services .

 Baker , A. E. Z. , Lane , A. , Angley , M. T. , &

 Young , R. L. ( 2008 ). The relationship between

sensory processing patterns and behavioural

responsiveness in autistic disorder: A pilot study .

Journal of Autism and Developmental Disorders ,

38 , 867 – 875 . doi:10.1007/s10803-007-0459-0

 Baloh , R. W. , & Honrubia , V. ( 1979 ). Clinical

neurophysiology of the vestibular system .

 Philadelphia, PA : F.A. Davis .

 Baranek , G. T. , Boyd , B. A. , Poe , M. D. , David ,

 F. J. , & Watson , L. R. ( 2007 ). Hyperresponsive

sensory patterns in young children with autism,

developmental delay, and typical development .

American Journal of Mental Retardation , 112 ( 4 ),

 233 – 245 . doi:10.1352/0895-8017(2007)112

[233:HSPIYC]2.0.CO;2

 Baranek , G. T. , David , F. J. , Poe , M. D. , Stone ,

 W. L. , & Watson , L. R. ( 2006 ). Sensory experience

questionnaire: Discriminating sensory features

in young children with autism, developmental

delays, and typical development. Journal of Child

Psychology and Psychiatry , 47 ( 6 ), 591 – 601 .

 Bar-Shalita , T. , & Cermak , S. A. ( 2016 ). Atypical

sensory modulation and psychological distress

in the general population. American Journal of

Occupational Therapy , 70 , 1 – 9 .

 Bar-Shalita , T. , Deutsch , L. , Honigman , L. , &

 Weissman-Fogel , I. ( 2015 ). Ecological aspects

of pain in sensory modulation disorder . Research

in Developmental Disabilities , 45–46 , 157 – 167 .

 doi:10.1016/j.ridd.2015.07.028

 Bar-Shalita , T. , Vatine , J. J. , & Parush , S. ( 2008 ).

 Sensory modulation disorder: A risk factor for

participation in daily life activities. Developmental

Medicine and Child Neurology , 50 ( 12 ), 932 – 937 .

 doi:10.1111/j.1469-8749.2008.03095.x

 Bauer , B. ( 1977 ). Tactile-sensitive behavior in

hyperactive and non-hyperactive children.

American Journal of Occupational Therapy , 31 ,

 447 – 450 .

 Bear , M. F. , Connors , B. W. , & Paradiso , M. A.

( 2015 ). Neuroscience: Exploring the brain

( 4th ed .). Philadelphia, PA : Lippincott Williams &

Wilkins .

 Ben-Sasson , A. , Cermak , S. A. , Orsmond , G. I. ,

 Tager-Flusberg , H. , Carter , A. S. , Kadlec , M. B. ,

& Dunn , W. ( 2007 ). Extreme sensory modulation

behaviors in toddlers with autism spectrum

disorders. American Journal of Occupational

Therapy , 61 , 584 – 592 .

 Ben-Sasson , A. , Cermak , S. A. , Orsmond , G. I. ,

 Tager-Flusberg , H. , Kadlec , M. B. , & Carter , A. S.

( 2008 ). Sensory clusters of toddlers with autism

spectrum disorders: Differences in affective

symptoms. Journal of Child Psychology and

Psychiatry , 49 , 817 – 825 .

 Ben-Sasson , A. , Hen , L. , Fluss , R. , Cermak , S. A. ,

 Engel-Yeger , B. , & Gal , E. ( 2009 ). A metaanalysis of sensory modulation symptoms in

individuals with autism spectrum disorders.

Journal of Autism and Developmental Disorders ,

39 ( 1 ), 1 – 11 . doi:10.1007/s10803-008-0593-3

 Ben-Sasson , A. , Soto , T. W. , Heberle , A. E. ,

 Carter , A. S. , & Briggs-Gowan , M. J. ( 2017 ).

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 177

 Early and concurrent features of ADHD and

sensory over-responsivity symptom clusters.

Journal of Attention Disorders , 21 , 835 – 845 .

 doi:10.1177/1087054714543495

 Ben-Sasson , A. , Soto , T. W. , Martínez-Pedraza ,

 F. , & Carter , A. S. ( 2013 ). Early sensory overresponsivity in toddlers with autism spectrum

disorders as a predictor of family impairment and

parenting stress. Journal of Child Psychology

and Psychiatry, and Allied Disciplines , 54 ( 8 ),

 846 – 853 . doi:10.1111/jcpp.12035

 Berlyne , D. E. ( 1960 ). Confl ict, arousal, & curiosity .

 New York, NY : McGraw-Hill .

 Berlyne , D. E. ( 1971 ). Aesthetics and psychobiology .

 New York, NY : Appleton-Century-Crofts .

 Blanche , E. I. , Bodison , S. , Chang , M. C. , & Reinoso ,

 G. ( 2012 ). Development of the Comprehensive

Observations of Proprioception (COP): Validity,

reliability, and factor analysis . American Journal

of Occupational Therapy , 66 ( 6 ), 691 – 698 .

 doi:10.5014/ajot.2012.003608

 Blanche , E. I. , & Schaff , R. C. ( 2001 ). Proprioception:

A cornerstone of sensory integration intervention .

 In S. S. Roley , E. I. Blanche , & R. C. Schaff

( Eds .), Understanding the nature of sensory

integration with diverse populations ( pp . 109 –

 124 ). San Antonio, TX : Pro-Ed .

 Bruneau , E. G. , Jacoby , N. , & Saxe , R. ( 2015 ).

 Empathic control through coordinated interaction

of amygdala, theory of mind and extended pain

matrix brain regions. NeuroImage , 114 , 105 – 119 .

 doi:10.1016/j.neuroimage.2015.04.034

 Cermak , S. ( 1988 ). The relationship between attention

defi cits and sensory integration disorders

(Part 1) . Sensory Integration Special Interest

Section Newsletter , 11 , 1 – 4 .

 Chang , M. C. , Parham , L. D. , Blanche , E. I. , Schell ,

 A. , Chou , C.-P. , Dawson , M. , & Clark , F. ( 2010 ).

 Autonomic and behavioral responses of children

with autism to auditory stimuli . American

Journal of Occupational Therapy: Offi cial

Publication of the American Occupational

Therapy Association , 66 ( 5 ), 567 – 576 . doi:10.5014/

ajot.2012.004242

 Cheung , P. P. P. , & Siu , A. M. H. ( 2009 ). A

comparison of patterns of sensory processing

in children with and without developmental

disabilities. Research in Developmental

Disabilities: A Multidisciplinary Journal , 30 ,

 1468 – 1480 . doi:10.1016/j.ridd.2009.07.009

 Corbett , B. A. , Schupp , C. W. , Levine , S. , &

 Mendoza , S. ( 2009 ). Comparing cortisol, stress,

and sensory sensitivity in children with autism.

Autism Research , 2 , 39 – 49 .

 Donovick , P. J. ( 1968 ). Effects of localized septal

lesions on hippocampal EEC activity in behavior

in rats . Journal of Comparative and Physiological

Psychology , 66 , 569 – 578 .

 Dunn , W. ( 1997 ). The impact of sensory processing

abilities on the daily lives of young children and

their families: A conceptual model . Infants and

Young Children , 9 , 23 – 25 .

 Dunn , W. ( 1999 ). Sensory Profi le . San Antonio, TX :

 The Psychological Corporation .

 Dunn , W. ( 2014 ). Sensory Profi le TM 2 . San Antonio,

TX : The Psychological Corporation .

 Dunn , W. , & Bennett , D. ( 2002 ). Patterns of sensory

processing in children with attention defi cit

hyperactivity disorder . Occupational Therapy

Journal of Research , 22 , 4 – 15 .

 Edelberg , R. ( 1972 ). The electrodermal system . In

 N. S. Greenfi eld & R. A. Sternbach ( Eds .),

Handbook of psychophysiology ( pp . 367 – 418 ).

 New York, NY : Holt, Rinehart, & Watson .

 Ermer , J. , & Dunn , W. ( 1998 ). The sensory profi le: A

discriminant analysis of children with and without

disabilities. American Journal of Occupational

Therapy , 52 , 283 – 290 .

 Fisher , A. G. ( 1991 ). Vestibular-proprioceptive

processing and bilateral integration and

sequencing defi cits . In A. G. Fisher , E. A. Murray ,

& A. C. Bundy ( Eds .), Sensory integration theory

and practice ( pp . 71 – 107 ). Philadelphia, PA :

F.A. Davis .

 Fisher , A. G. , & Bundy , A. C. ( 1989 ). Vestibular

stimulation in the treatment of postural and

related disorders. In O. D. Payton , R. P. DiFabio ,

 S. V. Paris , E. J. Protas , & A. F. VanSant ( Eds .),

Manual of physical therapy techniques

( pp . 239 – 258 ). New York, NY : Churchill

Livingstone.

 Fisher , A. G. , & Dunn , W. ( 1983 ). Tactile

defensiveness: Historical perspectives, new

research: A theory grows . Sensory Integration

Special Interest Section Newsletter , 6 ( 2 ), 1 – 2 .

 Fowles , D. C. ( 1986 ). The eccrine system

and electrodermal activity . In M. C. H.

 Coles , E. Dorchin , & S. W. Porges ( Eds .),

Psychophysiology: Systems, processes, and

applications ( pp . 51 – 96 ). New York, NY : Guilford

Press.

 Fried , P. A. ( 1972 ). The effect of differential

hippocampal lesions and pre- and post-operative

training on extinction. Revenue Canadienne de

Psychologie , 26 , 61 – 70 .

 Ghanizadeh , A. ( 2011 ). Sensory processing problems

in children with ADHD, a systematic review .

Psychiatry Investigation , 8 ( 2 ), 89 – 94 . doi:10.4306/

pi.2011.8.2.89

 Gilman , S. , & Newman , S. W. ( 1992 ). Essentials of

clinical neuroanatomy and neurophysiology

( 9th ed ., p . 4 ). Philadelphia, PA : F.A. Davis .

 Gothelf , D. , Furfaro , J. A. , Hoeft , F. , Eckert , M. A. ,

 Hall , S. S. , O’Hara , R. , . . . Reiss , A. L. ( 2008 ).

 Neuroanatomy of fragile X syndrome is associated

with aberrant behavior and the fragile X mental

retardation protein (FMRP). Annals Neurology ,

63 , 40 – 51 .

 Gray , J. A. ( 1982 ). The neuropsychology of anxiety .

 New York, NY : Claredon .

 Gray , J. A. ( 1987 ). The psychology of fear and stress .

 New York, NY : Cambridge University Press .

 Gray , T. S. , & Bingaman , E. W. ( 1996 ). The

amygdala: Corticotropin-releasing factor, steroids,

178 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

and stress. Critical Review of Neurobiology , 10 ,

 155 – 168 .

 Green , R. H. , & Schwartzbaum , J. S. ( 1968 ). Effects

of unilateral septal lesions on avoidance behavior,

discrimination reversal, and hippocampal EEG.

Journal of Comparative and Physiological

Psychology , 65 , 388 – 396 .

 Green , S. A. , Rudie , J. D. , Colich , N. L. , Wood , J. J. ,

 Shirinyan , D. , Hernandez , L. , . . . Bookheimer ,

S. Y. ( 2013 ). Overreactive brain responses to

sensory stimuli in youth with autism spectrum

disorders. Journal of the American Academy

of Child and Adolescent Psychiatry , 52 ( 11 ),

 1158 – 1172 . doi:10.1016/j.jaac.2013.08.004

 Green , S. A. , Ben-Sasson , A. , Soto , T. W. , &

 Carter , A. S. ( 2012 ). Anxiety and sensory overresponsivity in toddlers and autism spectrum

disorders: Bidirectional effects across time .

Journal of Autism and Developmental Disorders ,

42 , 1112 – 1119 . doi:10.1007/s10803-011-1361-3

 Grossman , S. P. ( 1978 ). An experimental “dissection”

of the septal syndrome. In Functions of the

septohippocampal system ( pp . 227 – 273 ). Ciba

Foundation Symposium 58 (new series). New

York, NY : Elsevier .

 Gunnar , M. , & Quevedo , K. ( 2007 ). The

neurobiology of stress and development. Annual

Review of Psychology , 58 , 145 – 173 . doi.

org/10.1146/annurev.psych.58.110405.085605

 Hanft , B. E. , Miller , L. J. , & Lane , S. J. ( 2000 ,

 September ). Towards a consensus in terminology

in sensory integration theory and practice:

Part 3: Sensory integration patterns of function and

dysfunction: Observable behaviors: Dysfunction

in sensory integration. Sensory Integration Special

Interest Section Quarterly , 23 , 1 – 4 .

 Head , H. ( 1920 ). Studies in neurology ( Vol. 2 ). New

York, NY : Oxford University .

 Hebb , D. O. ( 1949 ). The organization of behavior .

 New York, NY : Wiley .

 Hebb , D. O. ( 1955 ). Drives and the CNS (conceptual

nervous system). Psychological Review , 62 ,

 243 – 254 .

 Homberg , J. R. , Schubert , D. , Asan , E. , & Aron ,

 E. N. ( 2016 ). Sensory processing sensitivity

and serotonin gene variance: Insights into

mechanisms shaping environmental sensitivity .

Neuroscience and Biobehavioral Reviews , 71 ,

 472 – 483 .

 Isaacson , R. L. ( 1982 ). The limbic system ( 2nd ed. ).

 New York, NY : W.B. Saunders .

 Jaiswal , P. , Mohanakumar , K. P. , & Rajamma , U.

( 2015 ). Serotonin mediated immunoregulation

and neural functions: Complicity in the aetiology

of autism spectrum disorders. Neuroscience

& Biobehavioral Reviews , 55 , 413 – 431 .

 doi:10.1016/j.neubiorev.2015.05.013

 Juckel , G. ( 2015 ). Serotonin: From sensory

processing to schizophrenia using an

electrophysiological method . Behavioural

Brain Research , 277 , 121 – 124 . doi:10.1016/

j.bbr.2014.05.042

 Kepser , L.-J. , & Homberg , J. R. ( 2015 ). The

neurodevelopmental effects of serotonin: A

behavioural perspective. Behavioural Brain

Research , 277 , 3 – 13 . doi:10.1016/j.bbr.2014

.05.022

 Kern , J. K. , Trivedi , M. H. , Grannemann , B. D. ,

 Garver , C. R. , Johnson , D. G. , Andrews , A. A. ,

. . . Schroeder , J. L. ( 2007 ). Sensory correlations

in autism. Autism: The International Journal

of Research and Practice , 11 ( 2 ), 123 – 134 .

 doi:10.1177/1362361307075702

 Kerr , J. H. ( 1990 ). Stress and sport: Reversal theory .

 In J. G. Jones & L. Hardy ( Eds .), Stress and

performance in sport ( pp . 107 – 131 ). Chichester,

West Sussex, England : Wiley .

 Kerr , J. H. ( 1997 ). Motivation and emotion in sport .

 New York, NY : Psychology Press Ltd .

 Keuler , M. M. , Schmidt , N. L. , Van Hulle , C. A. ,

 Lemery-Chalfant , K. , & Goldsmith , H. H. ( 2011 ).

 Sensory overresponsivity: Prenatal risk factors

and temperamental contributions. Journal of

Developmental and Behavioral Pediatrics , 32 ( 7 ),

 533 – 541 . doi:10.1097/DBP.0b013e3182245c05

 Kientz , M. A. , & Dunn , W. ( 1997 ). A comparison

of the performance of children with and without

autism on the sensory profi le . American Journal

of Occupational Therapy , 51 , 530 – 537 .

 Kimball , J. G. ( 1976 ). Vestibular stimulation and

seizure activity . Center for the Study of Sensory

Integrative Dysfunction Newsletter (now Sensory

Integration International), July, 4 .

 Kimball , J. G. ( 1977 ). Case history follow up report .

Center for the Study of Sensory Integrative

Dysfunction Newsletter (now Sensory Integration

International), 5 .

 Kimball , J. G. ( 1999 ). Sensory integration frame of

reference: Theoretical base, function/dysfunction

continua, and guide to evaluation. In P. Kramer

& J. Hinojosa ( Eds .), Frames of reference for

pediatric occupational therapy ( 2nd ed. ,

 pp . 119 – 168 ). Philadelphia, PA : Lippincott

Williams & Wilkins .

 Kingsley , R. E. ( 2000 ). Concise text of neuroscience .

 Philadelphia, PA : Lippincott Williams & Wilkins .

 Knickerbocker , B. M. ( 1980 ). A holistic approach

to learning disabilities . Thorofare, NJ : C. B.

Slack.

 Lai , J.-S. , Parham , D. L. , & Johnson-Ecker ,

 C. ( 1999 ). Sensory dormancy and sensory

defensiveness: Two sides of the same coin?

Sensory Integration Special Interest Section

Quarterly , 22 , 1 – 4 .

 Lane , A. E. , Molloy , C. A. , & Bishop , S. L. ( 2014 ).

 Classifi cation of children with autism spectrum

disorder by sensory subtype: A case for sensorybased phenotypes. Autism Research , 7 ( 3 ),

 322 – 333 . doi:10.1002/aur.1368

 Lane , A. E. , Young , R. L. , Baker , A. E. , & Angley ,

 M. T. ( 2010 ). Sensory processing subtypes in

autism: Association with adaptive behavior .

Journal of Autism and Developmental Disorders ,

40 ( 1 ), 112 – 122 . doi:10.1007/s10803-009-0840-2

CHAPTER 6 Sensory Modulation Functions and Disorders ■ 179

 Lane , S. J. , Lynn , J. Z. , & Reynolds , S. ( 2010 ).

 Sensory modulation: A neuroscience and

behavioral overview . OT Practice , 15 ( 21 ),

37 – 44 .

 Lane , S. J. , Reynolds , S. , & Thacker , L. ( 2010 ).

 Sensory over-responsivity and ADHD:

Differentiating using electrodermal responses,

cortisol, and anxiety . Frontiers in Integrative

Neuroscience , 4 ( 8 ), 1 – 14 . doi:10.3389/

fnint.2010.00008

 Larson , K. A. ( 1982 ). The sensory history of

developmentally delayed children with and

without tactile defensiveness. American Journal of

Occupational Therapy , 36 , 590 – 596 .

 Lee , A. D. , Leow , A. D. , Lu , A. , Reiss , A. L. ,

 Hall , S. , Chiang , M.-C. , . . . Thompson , P. M.

( 2007 ). 3D pattern of brain abnormalities in

fragile X syndrome visualized using tensor-based

morphometry . Neuroimage , 34 , 924 – 938 .

 Leekam , S. R. , Nieto , C. , Libby , S. J. , Wing , L. , &

 Gould , J. ( 2007 ). Describing the sensory

abnormalities of children and adults with autism.

Journal of Autism and Developmental Disorders ,

37 , 894 – 910 . doi:10.1007/ s10803-006-0218-7

 Little , L. M. , Sideris , J. , Ausderau , K. , & Baranek ,

 G. T. ( 2014 ). Activity participation among

children with autism spectrum disorder . American

Journal of Occupational Therapy , 68, 177 – 185 .

 doi:10.5014/ajot.2014.009894

 Mangeot , S. D. , Miller , L. J. , McIntosh , D. N. ,

 McGrath-Clarke , J. , Simon , J. , Hagerman ,

 R. J. , & Goldson , E. ( 2001 ). Sensory modulation

dysfunction in children with attention-defi cithyperactivity disorder . Developmental Medicine

and Child Neurology , 43 , 399 – 406 .

 May-Benson , T. A. , & Koomar , J. A. ( 2007 ).

 Identifying gravitational insecurity in children:

A pilot study . American Journal of Occupational

Therapy , 61 , 142 – 147 .

 McIntosh , D. N. , Miller , L. J. , Shyu , V. , & Hagerman ,

 R. J. ( 1999 ). Sensory-modulation disruption,

electrodermal responses, and functional behaviors.

Developmental Medicine & Child Neurology , 41 ,

 608 – 615 .

 Melzack , R. , & Wall , P. D. ( 1965 ). Pain mechanisms:

A new theory . Science , 50 , 971 – 979 .

 Merriam Webster Online . ( 2015 ). Downloaded from

 http://www.merriam-webster.com/dictionary/

modulate

 Miller , L. J. , Anzalone , M. E. , Lane , S. J. , Cermak ,

 S. A. , & Osten , E. T. ( 2007 ). Concept evolution

in sensory integration: A proposed nosology for

diagnosis. American Journal of Occupational

Therapy , 61 ( 2 ), 135 – 140 .

 Miller , L. J. , McIntosh , D. N. , McGrath , J. , Shyu ,

 V. , Lampe , M. , Taylor , A. K. , . . . Hager , R. J.

( 1999 ). Electrodermal responses to sensory stimuli

in individuals with fragile X syndrome . American

Journal of Medical Genetics , 83 , 268 – 279 .

 Miller , L. J. , Nielsen , D. M. , & Schoen , S. A.

( 2012 ). Attention defi cit hyperactivity disorder

and sensory modulation disorder: A comparison

of behavior and physiology. Research in

Developmental Disabilities , 33 , 804 – 818 .

 doi:10.1016/j.ridd.2011.12.005

 Miller , L. J. , & Summers , C. ( 2001 ). Clinical

applications in sensory modulation dysfunction:

Assessment and intervention considerations. In

 S. S. Roley , E. I. Blanche , & R. C. Schaaf ( Eds .),

Understanding the nature of sensory integration

with diverse populations . San Antonio, TX :

 Therapy Skill Builders .

 Moayedi , M. , & Davis , K. D. ( 2013 ). Theories of

pain: From specifi city to gate control . Journal

of Neurophysiology , 109 ( 1 ), 5 – 12 . doi:10.1152/

jn.00457.2012

 Olton , D. S. , & Gage , F. H. ( 1974 ). Role of the fornix

in the septal syndrome. Physiology and Behavior ,

13 , 269 – 279 .

 Parham , D. L. , & Mailloux , Z. ( 1996 ). Sensory

integration. In J. Case-Smith , A. S. Allen , &

P. N. Pratt ( Eds .), Occupational therapy for

children ( 3rd ed. , pp . 307 – 355 ). St. Louis, MO :

 Mosby .

 Parush , S. , Sohmer , H. , Steinberg , A. , & Kaitz , M.

( 2007 ). Somatosensory function in boys with

ADHD and tactile defensiveness. Physiology

& Behavior , 90 ( 4 ), 553 – 558 . doi:10.1016/j.

physbeh.2006.11.004

 Porges , S. W. ( 2007 ). The polyvagal perspective .

Biological Psychology 74 ( 2 ), 116 – 143 .

 Pribram , C. ( 1975 ). Arousal, activation and effort in

the control of attention. Psychological Review , 82 ,

 116 – 149 .

 Purves , D. , Augustine , G. J. , Fitzpatrick , D. , Hall ,

 W. C. , LaMantia , A.-S. , & White , L. E. ( 2011 ).

Neuroscience ( 5th ed. ). Cambridge, MA : Sinauer

Associates, Inc .

 Recio , G. , Conrad , M. , Hansen , L. B. , & Jacobs ,

 A. M. ( 2014 ). On pleasure and thrill: The

interplay between arousal and valence during

visual word recognition. Brain and Language ,

134 , 34 – 43 . doi:10.1016/j.bandl.2014.03.009

 Reiss , A. L. , Abrams , M. T. , Greenlaw , R. , Freund ,

 L. , & Denkla , M. B. ( 1995 ). Neurodevelopmental

effects of the FMR-1 full mutation in humans .

Nature and Medicine , 1 , 159 – 167 .

 Reiss , A. L. , Lee , J. , & Freund , L. ( 1994 ).

 Neuroanatomy of fragile X syndrome: The

temporal lobe . Neurology , 44 , 1317 – 1324 .

 Restak , R. ( 1995 ). Brainscapes . New York, NY :

 Hyperion .

 Reynolds , S. , Bendixen , R. M. , Lawrence , T. , &

 Lane , S. J. ( 2011 ). A pilot study examining

activity participation, sensory responsiveness,

and competence in children with high functioning

autism spectrum disorder . Journal of Autism and

Developmental Disorders , 41 ( 11 ), 1496 – 1506 .

 doi:10.1007/s10803-010-1173-x

 Reynolds , S. , & Lane , S. J. ( 2008 ). Diagnostic

validity of sensory over-responsivity: A review of

the literature and case reports. Journal of Autism

and Developmental Disorders , 38 , 516 – 529 .

 doi:10.1007/s10803-007-0418-9

180 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 Reynolds , S. , Lane , S. J. , & Gennings , C. ( 2009 ).

 The moderating role of sensory over-responsivity

in HPA activity: A pilot study with children

diagnosed with ADHD. Journal of Attention

Disorders , 13 , 468 – 478 .

 Royeen , C. B. ( 1989, August ). Tactile defensiveness.

An overview of the construct. Paper presented

at the International Society for Social Pediatrics,

Brixen, Italy .

 Royeen , C. B. , & Lane , S. J. ( 1991 ). Tactile

processing and sensory defensiveness. In A. G.

 Fisher , E. A. Murray , & A. C. Bundy ( Eds .),

Sensory integration: Theory and practice

( pp . 108 – 136 ). Philadelphia, PA : F.A. Davis .

 Scardina , V. ( 1986 ). A. Jean Ayres lectureship .

Sensory Integration Newsletter , 14 , 2 – 10 .

 Schneider , A. , Hagerman , R. J. , & Hessl , D. ( 2009 ).

 Fragile X syndrome—From genes to cognition .

Developmental Disabilities Research Reviews ,

15 ( 4 ), 333 – 342 . doi:10.1002/ddrr.80

 Schneider , M. L. , Moore , C. F. , Larson , J. A. , Barr ,

 C. S. , DeJesus , O. T. , & Roberts , A. D. ( 2009 ).

 Timing of moderate level prenatal alcohol

exposure infl uences gene expression of sensory

processing behavior in rhesus monkeys. Frontiers

in Integrative Neuroscience , 3 , 1 – 9 . doi:10.3389/

neuro.07.030.2009

 Schoen , S. A. , Miller , L. J. , Brett-Green , B.

A. , & Nielsen , D. M. ( 2009 ). Physiological

and behavioral differences in sensory

processing: A comparison of children with

autism spectrum disorder and sensory

modulation disorder . Frontiers in Integrative

Neuroscience , 3 ( November ), 1 – 11 . doi:10.3389/

neuro.07029.2009

 Schoen , S. A. , Miller , L. J. , Brett-Green , B. A. ,

 Reynolds , S. , & Lane , S. J. ( 2008 ). Arousal and

reactivity in children with sensory processing

disorder and autism spectrum disorder .

Psychophysiology , 45 , S102 .

 Schoen , S. A. , Miller , L. J. , & Sullivan , J. C. ( 2014 ).

 Measurement in sensory modulation: The Sensory

Processing Scale Assessment. American Journal of

Occupational Therapy , 68 , 522 – 530 . doi:10.5014/

ajot.2014.012377

 Schoen , S. A. , Miller , L. J. , & Sullivan , J. ( 2016 ).

 The development and psychometric properties

of the Sensory Processing Scale Inventory: A

report measure of sensory modulation. Journal of

Intellectual and Developmental Disability , 42 ( 1 ),

 12 – 21 . Doi: 10.31109/13668250.2016.1195490

 Shimizu , V. , Bueno , O. , & Miranda , M. ( 2014 ).

 Sensory processing abilities of children with

ADHD. Brazilian Journal of Physical Therapy ,

18 ( 4 ), 343 – 352 . doi:10.1590/bjpt-rbf.2014.0043

 Siegel , A. , & Sapru , H. N. ( 2015 ). Essential

neuroscience ( 3rd ed. ). Philadelphia, PA :

 Lippincott Williams & Wilkins .

 Tomchek , S. D. , & Dunn , W. ( 2007 ). Sensory

processing in children with and without autism: A

comparative study using the short sensory profi le .

American Journal of Occupational Therapy ,

61 ( 2 ), 190 – 200 .

 Tomchek , S. D. , Little , L. M. , & Dunn , W. ( 2015 ).

 Sensory pattern contributions to developmental

performance in children with autism spectrum

disorder . American Journal of Occupational

Therapy , 69 , 6905185040 . doi:10.5014/

ajot.2015.018044

 Van Hulle , C. A. , Schmidt , N. L. , & Goldsmith ,

 H. H. ( 2012 ). Is sensory over-responsivity

distinguishable from childhood behavior

problems? A phenotypic and genetic analysis .

Journal of Child Psychology and Psychiatry,

and Allied Disciplines , 53 ( 1 ), 64 – 72 .

 doi:10.1111/j.1469-7610.2011.02432.x

 Veenstra-VanderWeele , J. , Muller , C. L. , Iwamoto ,

 H. , Sauer , J. E. , Owens , W. A. , Shah , C. R. ,

. . . Blakely , R. D. ( 2012 ). Autism gene variant

causes hyperserotonemia, serotonin receptor

hypersensitivity, social impairment and repetitive

behavior . Proceedings of the National Academy

of Sciences , 109 ( 14 ), 5469 – 5474 . doi:10.1073/

pnas.1112345109

 Watson , L. R. , Patten , E. , Baranek , G. T. , Poe , M. D. ,

 Boyd , B. A. , Freuler , A. , & Lorenzi , J. ( 2011 ).

 Differential associations between sensory response

patterns and language, social, and communication

measures in children with autism or other

developmental disabilities. Journal of Speech,

Language, and Hearing Research , 54 ,

1562 – 1576 .

 Waxman , S. G. ( 2010 ). Clinical neuroanatomy ( 26th

ed. ). New York, NY : McGraw-Hill .

 Wiggins , L. D. , Robins , D. L. , Bakeman , R. , &

 Adamson , L. B. ( 2009 ). Brief report: Sensory

abnormalities as distinguishing symptoms of

autism spectrum disorders in young children.

Journal of Autism and Developmental Disorders ,

39 ( 7 ), 1087 – 1091 . doi:10.1007/s10803-009-0711-x

 Wilbarger , P. , & Royeen , C. B. ( 1987, May ). Tactile

defensiveness: Theory, applications and treatment .

 Annual Interdisciplinary Doctoral Conference,

Sargent College, Boston University .

 Wilbarger , P. , & Wilbarger , J. ( 1991 ). Sensory

defensiveness in children aged 2–12: An

intervention guide for parents and other

caregivers . Denver, CO : Avanti Educational

Programs.

 Yang , C.-J. , Tan , H.-P. , & Du , Y.-J. ( 2014 ). The

developmental disruptions of serotonin signaling

may be involved in autism during early

brain development. Neuroscience , 267 , 1 – 10 .

 doi:10.1016/j.neuroscience.2014.02.021

 Yochman , A. , Parush , S. , & Ornoy , A. ( 2004 ).

 Responses of preschool children with and without

ADHD to sensory events in daily life . American

Journal of Occupational Therapy , 58 ( 3 ), 294 – 302 .

 Retrieved from http://www.ncbi.nlm.nih.gov/

pubmed/15202627

181

CHAPTER

7

Sensory Discrimination

Functions and Disorders

 Shelly J. Lane , PhD, OTR/L, FAOTA ■ Stacey Reynolds , PhD, OTR/L

 Chapter 7

 Sensations are “food” or nourishment for the nervous system . . . every

sensation is a form of information. . . . Without a good supply of many

kinds of sensations, the nervous system cannot develop adequately.

 —A. Jean Ayres

Upon completion of this chapter, the reader will be able to:

✔ Appraise the foundations for sensory

discrimination within each sensory system.

✔ Recognize behaviors associated with sensory

discrimination disorders across all sensory

systems.

✔ Describe the interactions between sensory

systems relative to sensory discrimination.

✔ Identify tools for the measurement of sensory

discrimination abilities.

LEARNING OUTCOMES

Purpose and Scope

 The theoretical model presented in Chapter 1

(Sensory Integration: A. Jean Ayres’ Theory

Revisited) depicts sensory perception as a foundation for sensory discrimination, postural ocular

skills, visual motor skills, and body scheme

development, and all these function as a basis for

the development of praxis. Using a sensory integrative framework, therapists will often assess

sensory discrimination in order to understand

the underlying components of praxis and praxisrelated disorders. Similarly, treatment from an SI

perspective does not focus on the development

of discrimination skills in isolation but rather as

elements of adaptive environmental interactions.

It is in this context that we examine discrimination in our sensory systems.

 In this chapter, we will present a bit more

detail on neural connections within the sensory

systems, examine foundations for discrimination

within and between sensory systems, ground this

information in clinical links, and take a look at

assessment approaches. Some of the assessment

approaches are outside the typical realm of occupational therapy and sensory integration (SI)

theory but warrant inclusion here because they

contribute to our understanding of the bigger

picture associated with sensory processing. Intervention approaches for improving sensory discrimination are addressed in Chapter 12 (The

Art of Therapy), Chapter 13 (The Science of

Intervention: Creating Direct Intervention from

Theory), and Chapter 18 (Complementary Programs for Intervention).

Sensory Discrimination

Sensory perception involves the interpretation

of sensory stimuli and the use of that interpretation as a basis for interacting with the world. The

term sensory discrimination refers to the ability

to tell two stimuli apart ( Macmillan & Creelman,

182 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 2005 ). Although this is a relatively simple defi -

nition, the ability to discriminate is a complex

neurological function that can be altered based

on experience, psychological state, and the environment. Accuracy and effi ciency in discrimination across all sensory systems contribute to

an individual ’ s ability to move through space,

effectively interact with objects in the environment, and perform basic daily occupations such

as reading, eating, and dressing, as well as fulfi lling roles such as student, sibling, and friend.

The role of sensory discrimination is to allow

us to make quick decisions about environmental

inputs that support decision-making relative to

behavior. A defi ciency in the ability to discriminate sensations in any sensory system, or across

sensory systems, in a way that impairs occupational performance may be considered a sensory

discrimination disorder ( Miller, Anzalone,

Lane, Cermak, & Osten, 2007 ).

 Merfeld ( 2011 ) acknowledged two aspects

of discrimination: detection and recognition.

Detection refers to the ability to discriminate a

positive stimulus (e.g., an auditory tone) from

a null stimulus (e.g., no sound). Hearing tests

usually use a detection paradigm to determine

whether someone can or cannot hear at specifi c

frequencies. Recognition is what we more commonly associate with discriminative capabilities,

which is the ability to tell two positive (non-null)

stimuli apart. For example, if an individual is

exposed to two tones, one at 75 dB and one at

120 dB, auditory discriminatory functions would

allow the individual to recognize which of those

tones was louder. In the case of movement discrimination, a person with intact discriminatory

functions would be able to recognize if he or she

had moved up or down on an escalator, without

visual cues. For the purposes of this chapter, the

general term discrimination will be used to refer

to the ability to tell two stimuli apart, whether or

not one stimulus is null.

 Discrimination occurs before conscious perception of a stimulus. Although discrimination

does not require conscious effort, discriminatory

functions are intimately linked with cognitive

areas of attention, memory, and decision-making.

Behavioral methods of assessing discrimination often require attention and cooperation

on the part of the participant, which can make

assessment of discriminatory abilities in children potentially diffi cult. Children with greater

attention skills have been shown to score higher

on tests of sound (linguistic) discrimination compared with children who have more diffi culty

maintaining their attention ( Davids et al., 2011 ).

This means that the level of attention or saliency

that an individual attributes to sensations in his

or her environment may affect the quality and

accuracy in which those inputs are perceived

and stored. In many standardized assessments of

discrimination, two stimuli are presented sequentially in a trial. A comparison or judgment is

made against the short-term memory left by the

fi rst stimulus. In daily life, the ability to identify or classify a sensory stimulus requires the

comparison of that stimulus to a reference stored

in long-term memory ( Romo & de Lafuente,

 2013 ). Because precise and effi cient discrimination of sensory inputs is a prerequisite for accurate memory storage, individuals with sensory

discrimination disorders may have diffi culty not

only with processing sensory feedback but also

with the feedforward mechanisms necessary for

decision-making and the motor commands used

to execute those decisions ( Pleger & Villringer,

 2013 ).

 Discrimination is believed to occur across all

sensory systems (i.e., auditory, visual, gustatory,

olfactory, tactile, proprioceptive, and vestibular),

though the integration of accurate sensory information from each system is necessary for many

daily life skills. For example, both tactile and

proprioceptive discrimination functions contribute to the ability to type on a keyboard or manipulate a pencil for writing without a constant need

for visual monitoring. Olfactory and gustatory

discrimination skills are necessary for optimal

fl avor recognition and play a role in determining

which foods we eat. The ability to move through

space is heavily dependent on vestibular, proprioceptive, and visual discrimination skills. For

the purposes of organizing this chapter, auditory

and visual discrimination will be discussed separately, whereas chemosensations of taste and

smell have been grouped together; proprioception is addressed in conjunction with both vestibular and tactile functions.

HERE ’ S THE POINT

• Sensory perception and sensory discrimination

refer to different processes.

CHAPTER 7 Sensory Discrimination Functions and Disorders ■ 183

• The role of sensory discrimination is to guide

us in decision-making regarding environmental

inputs; in this way, discrimination infl uences

behavior.

• Sensory detection and recognition are

components of sensory discrimination.

• Sensory discrimination is infl uenced by multiple

factors including attention, cognition, and

memory.

Sensory Discrimination:

An Illustration

CASE STUDY ■ RICKY

 When he was 6 years old, Ricky was referred to

an occupational therapist because of signifi cant

motor clumsiness. He could not walk through

his classroom without bumping into desks or

tripping over objects in his path. Although he

lived only two blocks from school, he was not

allowed to walk to school by himself because

he could not determine when it was safe to

cross the street. On the playground, he misjudged the movement of the swings, resulting

in many “near misses” when he walked by children who were swinging.

 Ricky had trouble fi nding his way around

the school and did not seem to know how to

use landmarks as a guide. Gym class presented

real challenges. Ricky could not catch a ball

unless it hit him in the chest so that he could

trap it. When playing dodgeball, he was always

the fi rst eliminated.

 In his classroom, Ricky was able to read

as well as his peers. Printing, however, was a

challenge. He had diffi culty holding the pencil;

it either slipped from his fi ngers or he gripped

it so tight his hand got tired very fast. He could

not keep his letters within the lines, and the

size and spacing of his letters varied tremendously. Math was also diffi cult. When using

counters to solve a problem, Ricky counted

some of them more than once and some

not at all.

 Ricky still needed help in dressing. He put

on shirts backward, and both his legs ended

up in the same pant leg. He had diffi culty with

fasteners such as buttons and zippers. He wore

slip-on shoes because he could not tie shoelaces, but sometimes he tried to put one shoe

on upside down, with the sole facing up, and he

could not fi gure out what was wrong.

 Children such as Ricky are familiar to many

occupational therapists, and his description fi ts

many children with sensory integrative dysfunction. Ricky ’ s problems are complex, likely

involving poor discrimination across multiple

sensory systems. We will look more carefully

at these concerns as we move through this

chapter.

Touch Discrimination

 The tactile system encompasses a diverse and

widespread set of receptors, and it includes

responses that are both discriminative and protective. Here we focus on discriminative touch;

the protective aspects of this system were

covered in Chapter 6 (Sensory Modulation Functions and Disorders). The term somatosensation

is used to include both touch and proprioception,

and both of these senses underlie discrimination.

As such, we address proprioception here relative to its contribution to skills, such as threedimensional shape recognition, and will also

address it relative to the discrimination of movement later in this chapter.

Foundations of Somatosensory

Discrimination

 Discrimination within the somatosensory system

relies on complex interpretation of inputs from

multiple skin receptors ( Bear, Connors, & Paradiso, 2015 ; Purves et al., 2011 ). This system is

differently organized than other sensory systems

in its wide distribution of receptors designed to

detect multiple features of a stimulus, such as

texture, shape, force, and movement. Receptors

associated with discrimination vary considerably in their characteristics; within this system

are receptors with fast and slow adaptation rates,

small or relatively large receptive fi elds, varying

thresholds for activation, and varying transmission speeds for information to reach the central

nervous system (CNS; Abraira & Ginty, 2013 ;

 McGlone, Wessberg, & Olausson, 2014 ; see

 Table 4-1 ). Our knowledge of the receptors and

their processing properties comes primarily from

research conducted on what is called glabrous,

or non-hairy, skin, such as that on the palm of

184 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

the hand. Receptors contributing to somatosensory discrimination include Meissner corpuscles,

which are relatively superfi cial and thus very sensitive to skin indentation. It has been noted that

these receptors respond to movement of texture

on the skin and guide grip in their ability to

detect slippage of a held object. Pacinian corpuscles lie deeper in the skin and respond to deeper

touch and vibratory input; they are thought to

contribute to grip and skilled tool use. Merkel

cells or discs are very sensitive to edges, points,

and curves, contributing to detection of form and

texture. Ruffi ni endings are less well understood

but contribute to our ability to detect movement

of the fi ngers, a proprioceptive function ( Purves

et al., 2011 ). No other sensory system has such

a diverse set of receptors. Proprioceptive sensations also come from joint receptors and muscle

spindles; these receptors transduce different

movement patterns and provide information

about where body parts are in space and in relation to one another.

 Receptors attach to fi bers that project to the

dorsal horn of the spinal cord and ascend to the

medulla, synapsing there in either the nucleus

gracilis (lower extremity fi bers) or nucleus

cuneatus (upper limb, trunk, neck fi bers), and

it is likely that some aspects of somatosensory

perception begin here ( McGlone et al., 2014 ).

The pathway associated with transmitting this

information from the spinal cord to the CNS,

the dorsal column medial lemniscal system

(DCML), was described in Chapter 4 (Structure and Function of the Sensory Systems; see

 Fig. 4-14 ). This pathway projects from these

medullary nuclei to the ventral posterior thalamic nuclei, with each receptor type connecting

with unique thalamic cells. At the thalamus there

is further interpretation of somatosensory information ( Bear et al., 2015 ). Projections then go

to the primary sensory cortex, S-I. This region

can be subdivided into Brodmann areas 3a, 3b,

1, and 2, and within each area is a map of the

body: a sensory homunculus (see Fig. 4-15 ).

The maps refl ect the density of receptors in any

given area of the body; as such, the hand and

mouth region are very large, whereas the trunk

and leg regions are relatively small. The density

of receptors has been linked with their function

such that those areas dense in receptors have

functions that require detailed sensory information. For instance, the hand and fi ngers are well

innervated, supporting the need for precise information from these regions to interpret input and

lay a foundation for fi ne motor control. Similarly,

the dense innervation around the lips and tongue

is important for speech production and eating

skills ( Bear et al., 2015 ).

 Cortical cells in S-I respond to different types

of inputs, which becomes important when considering dysfunction. Area 3b appears to be a

primary somatosensory reception area in that

damage here impacts all aspects of somatosensory perception; in contrast, damage to area 1

leads to diffi culty with texture discrimination

and to area 2 with size and shape discrimination

( Bear et al., 2015 ; Purves et al., 2011 ). Areas 2

and 3 play an important role in proprioceptive

processing because they receive information primarily from muscle spindles and Golgi tendon

organs. From S-I, information is projected to

S-II, the secondary somatosensory cortex, where

new sensory discriminations are thought to occur

via integration of signals from both the ventral

posterior lateral (VPL) nucleus of the thalamus

and S-I. Additional projections go to areas 5

and 7 of the parietal lobe. Area 5 plays a role in

integration of touch and proprioception, and in

area 7 somatosensory information is integrated

with visual inputs (see Fig. 4-7 ).

 Somatosensory discrimination underlies our

ability to use our hands to grip and manipulate

tools and objects. You might hypothesize that

Ricky has diffi culty with somatosensory discrimination because one of his concerns is diffi culty

manipulating and gripping his pencil with the

right amount of force. He also struggles with fasteners and tying his shoes, which may be because

of poor tactile discrimination.

 Skills associated with somatosensory discrimination are essential for interaction and function

in everyday life. Discrimination of somatosensation involves being able to identify the spatial

and temporal qualities of sensation. It encompasses skills including two-point discrimination,

stereognosis, texture discrimination, and detection of direction of touch. Two-point discrimination, a measure of tactile-spatial acuity, is the

ability to detect two distinct points on the skin,

applied simultaneously. This skill is thought by

many investigators to be more challenging the

closer together the two points of touch lie, and

in a typical nervous system the limits of this

skill are paralleled by the size of the receptive

CHAPTER 7 Sensory Discrimination Functions and Disorders ■ 185

fi eld ( Purves et al., 2011 ). Interestingly, there is

some recent evidence that suggests this is inaccurate and that basic two-point discrimination

testing provides an infl ated view of this aspect

of tactile perception. Tong, Mao, and Goldreich

 ( 2013 ) suggested that two-point tactile orientation discrimination provides a better means of

determining this function. This involves being

able to distinguish whether a stimulus is placed

on the skin in a vertical or horizontal orientation.

Stereognosis is a commonly assessed discriminative skill associated with the somatosensory

system. This skill requires integration of tactile

and proprioceptive inputs in three-dimensional

object discrimination; stereognosis also involves

visual memory, bringing us back to the importance of multisensory integration relative to

functional use of sensory discrimination.

 Thinking again about the diffi culty Ricky

has with his pencil suggests poor integration of

touch and proprioception. How the hand is used

in tactile exploration infl uences the information

obtained and, as such, plays a role in the accuracy of this discriminatory skill. The ability to

use one ’ s hands to explore objects and integrate

sensory input matures gradually throughout

childhood ( Kalagher & Jones, 2011a ). Although

children younger than 5 years of age appear to

have the ability to use suffi cient hand skills to

identify objects, they do not consistently do so

( Kalagher & Jones, 2011b ). At 6 years of age,

Ricky should be able to use tactile discrimination

to support his ability to button, pull up a zipper,

and tie his shoes. The report that he has diffi -

culty with these tasks indicates that the therapist

should be looking at touch discrimination as a

contributing factor in Ricky ’ s manipulation and

dexterity skills.

 Inadequate somatosensory discrimination was

repeatedly linked with motor planning defi cits

in the early work of Ayres ( 1965, 1966a, 1966b,

1969, 1971, 1972b, 1977, 1989 ). As explained in

 Chapter 5 (Praxis and Dyspraxia), the term somatodyspraxia has been used to classify children

who have diffi culty planning and executing novel

motor actions and who demonstrate poor body

scheme or body awareness and inadequate tactile

perception ( Ayres, 1979, 2005 ). Defi cits seen

in children with somatodyspraxia may include

poor playground skills, diffi culty manipulating

tools, or challenges learning to ride a bike. You

may recognize many of these concerns apply to

Ricky. In recent work, Mailloux and colleagues

( Mailloux et al., 2011 ) indicated that somatodyspraxia overlapped with visuodyspraxia,

forming a single factor in their analysis; this

interface between visually-based dyspraxia and

somatosensory-based dyspraxia requires further

consideration.

Measurement of Somatosensory

Discrimination

 Of the tools that are currently available, tactile

and kinesthetic subtests from the Sensory Integration and Praxis Tests (SIPT) offer the most

comprehensive perspective on somatosensory

processing in children. Thus, in spite of its

age, the SIPT can provide insight into overall

processing within the somatosensory system.

More information on the SIPT is presented in

 Chapter 8 (Assessment of Sensory Integration

Functions Using the Sensory Integration and

Praxis Tests). Pertinent subtests from the SIPT

include the range of tactile tests, generally done

with vision occluded:

• Manual Form Perception (MFP) a test

of stereognosis requiring tactile shape

identifi cation

• Two-point discrimination (Localization of

Tactile Stimuli; LTS) examining the ability

to distinguish where a tactile stimulus is

delivered on the hand or arm

• Finger identifi cation (Finger Identifi cation;

FI)

• Graphesthesia (Graphesthesia; GRA), a test

of dynamic tactile sensation in which the

child replicates a design drawn on the back

of the hand

• Kinesthesia (Kinesthesia; KIN), which

examines conscious proprioception in asking

the child to replicate a movement of the arm

and hand from one point to another

 Ricky was assessed using the SIPT. His standardized scores on the subtests looking at touch

and proprioception are presented in Table 7-1

and Figure 7-1 . Keep in mind that when scores

are standardized, typical performance is refl ected

in scores within 1 standard deviation from the

mean. The majority of Ricky ’ s scores fall greater

than 1.0 below the mean, indicating that he has

diffi culty with many aspects of somatosensory

discrimination.

186 ■ PART II The Neuroscience Basis of Sensory Integration Disorders

 Although the SIPT is the most thorough test

of sensory discrimination available for the pediatric population, other assessments may provide

insight into somatosensory processing in children such as Ricky. For example, the National

Institutes of Health (NIH) Toolbox is a set of

psychometrically sound performance-based and

self-report measures useful in screening cognition, emotion, motor skills, and sensation across

the life span ( HealthMeasures, 2017 ). The sensation battery of the NIH Toolbox has items

addressing somatosensory function, including a

Brief Kinesthesia Test (based on the SIPT Kinesthesia test) and a Tactile Discrimination Test

addressing texture discrimination (W. Dunn et al.,

 2015 ). Other test batteries include tactile items

(e.g., the Miller Assessment for Preschoolers),

but the items generally do not stand on their own.

HERE ’ S THE POINT

• Discrimination in the somatosensory system

involves an array of receptor types.

• The density of peripheral receptors is refl ected

in the needed function of that region of the

body.

• Somatosensory discrimination infl uences our

ability and skill in using our hands and body for

action.

• Tactile discrimination has been linked with

praxis.

• Sensory integrative assessment of the

somatosensory system can be largely

accomplished using subtests of the SIPT.

Movement Discrimination

 The ability of an individual to perceive movement of his or her body through space requires

integration of information from multiple sensory

systems, including the proprioceptive and vestibular systems. Accurate discrimination of sensation in these systems is necessary for the brain

to generate accurate estimates of head and body

position, orientation, and speed and timing of

motion ( Naseri & Grant, 2012 ).

Foundations of Proprioceptive

Discrimination

 The reception and transmission of proprioceptive sensation was touched on previously and

presented in somewhat more detail in Chapter 6

(Sensory Modulation Functions and Disorders).

Accuracy in interpreting and distinguishing proprioceptive information provides the foundation

upon which individuals are able to monitor their

own movement patterns, make adjustments to

motor plans, and effectively execute novel and

learned motor tasks ( Murray-Slutsky & Paris,

 2014 ). Proprioception contributes heavily to

an individual ’ s overall body scheme, the neural

representation of the body used to guide motor

activity ( Holmes & Spence, 2004 ). Although

body scheme is thought to represent one construct of how the brain interprets the body as

a whole, research has shown that the ability to

discriminate between movements of different

extent using proprioception is site specifi c ( Han,

Waddington, Adams, & Anson, 2013 ). Athletes,

TABLE 7-1 Somatosensory Scores on the SIPT

for Ricky

SUBTEST STANDARD SCORE

MFP –1.9

LTS –0.8

FI –1.1

GRA –2.3

KIN –1.5

FIGURE 7-1 Ricky ’ s standardized SIPT somatosensory

scores. Scores below –1.0 are considered potentially

problematic, but it is important to look for clusters.

Ricky scored below –1.0 on all but one of these

subtests, indicating diffi culty with somatosensory

discrimination.

2.5 2 1.5 1 0.5 0

SIPT subtests: KIN: kinesthesia; GRA: graphesthesia;

Fl: finger identification; LTS: localization of tactile stimuli;

MFP: manual form perception

MFP

LTS

FI

GRA

KIN

sensory integration disorder

sensory integration

sensory integration therapy

sensory integration dysfunction

sensory integration therapy near me

sensory integration frame of reference

sensory integration and praxis test

sensory integration theory

sensory integration disorder icd 10

sensory integration and the child

sensory integration activities

sensory integration assessment

sensory integration autism

sensory integration and the child pdf

sensory integration and praxis test (sipt)

sensory integration adults

sensory integration activities for adults

sensory integration approach

sensory integration books

sensory integration brushing

sensory integration brain

sensory integration billing code

sensory integration benefits

sensory integration book pdf

sensory integration balance training

sensory integration behavior problems

sensory integration books for occupational therapists

sensory integration by jean ayres

sensory integration certification

sensory integration clinic

sensory integration clinic boston

sensory integration cpt code

sensory integration courses

sensory integration challenges

sensory integration center

sensory integration ceu courses

sensory integration clinic near me

sensory integration catalog

sensory integration disorder symptoms

sensory integration definition

sensory integration disorder in adults

sensory integration disorder treatment

sensory integration disorder dsm 5

sensory integration disorder autism

sensory integration dysfunction icd 10

sensory integration examples

sensory integration evaluation

sensory integration exercises

sensory integration equipment

sensory integration exercises for adults

sensory integration education

sensory integration early childhood

sensory integration early intervention

sensory integration emotional regulation

sensory integration evidence based practice

sensory integration for adults

sensory integration for

sensory integration for autism

sensory integration fidelity measure

sensory integration for adhd

sensory integration for dementia

sensory integration for occupational therapy

sensory integration fact sheet aota

sensory integration for anxiety

sensory integration goal bank

sensory integration gym

sensory integration goals

sensory integration global network

sensory integration google scholar

sensory integration group activities

sensory integration guide for parents

what is the meaning of sensory integration

does sensory integration work

why sensory integration is important

sensory integration handout for parents

sensory integration heavy work

sensory integration hyposensitivity

sensory integration hypersensitivity

sensory integration head banging

sensory integration history

sensory integration hierarchy

sensory integration hk

sensory integration hammocks

sensory integration help

sensory integration issues

sensory integration interventions

sensory integration is critical to the development of

sensory integration inventory

sensory integration in the classroom

sensory integration interventions occupational therapy

sensory integration interventions examples

sensory integration icd 10

sensory integration involves

sensory integration inventory revised

sensory integration jean ayres

sensory integration jobs

sensory integration jean ayres pdf

sensory integration jobs uk

sensory integration journal article

sensory integration journal

sensory integration ترجمة

sensory processing jobs

sensory processing jumping

sensory integration therapy jobs

sensory integration kindergarten

sensory integration kit

sensory integration kinesthesia

sensory integration key role

sensory processing kinesthesia

sensory integration therapy kolkata

sensory integration therapy kent

sensory integration center kota kinabalu

sensory integration therapy katy

sensory integration disorder kindergarten

sensory integration level 1

sensory integration login

sensory integration level 2

sensory integration levels

sensory integration level 3

sensory integration learning disabilities

sensory integration london

sensory integration learning

sensory integration level 4

sensory integration low registration

sensory integration model

sensory integration meaning

sensory integration massage

sensory integration music therapy

sensory integration milestones

sensory integration masters

sensory integration module 1

sensory integration meaning in hindi

sensory integration materials

sensory integration module 2

sensory integration near me

sensory integration network

sensory integration needs

sensory integration network login

sensory integration nhs

sensory integration network jobs

sensory integration neurodiversity

sensory integration neuroscience

sensory integration network find a therapist

sensory integration network courses

sensory integration occupational therapy

sensory integration ot

sensory integration ot near me

sensory integration occupational therapy interventions

sensory integration occupational therapy near me

sensory integration occupational therapy activities

sensory integration occupational therapy goals

sensory integration ot theory

sensory integration observation worksheet

sensory integration occupational therapy assessment

sensory integration praxis test

sensory integration problems

sensory integration processing disorder

sensory integration pdf

sensory integration psychology

sensory integration proprioception

sensory integration pediatric occupational therapy

sensory integration pediatrics

sensory integration principles

sensory integration play

sensory integration questionnaire

sensory integration quizlet

sensory integration quotes

sensory integration questions

sensory integration quadrants

sensory integration quiz

sensory integration qualification

sensory processing questionnaire pdf

sensory processing quadrants

sensory processing quotes

sensory integration research

sensory integration room

sensory integration resources

sensory integration room design

sensory integration room equipment

sensory integration room ideas

sensory integration register

sensory integration report

sensory integration research articles

sensory integration rcot

sensory integration strategies

sensory integration specialist

sensory integration skills

sensory integration speech therapy

sensory integration symptoms

sensory integration swings

sensory integration syndrome

sensory integration screening questionnaire

sensory integration supplies

sensory integration systems

sensory integration training

sensory integration therapy for adults

sensory integration therapy at home

sensory integration theory and practice

sensory integration techniques

sensory integration therapy for autism

sensory integration therapy for adults near me

sensory integration usc

sensory integration uk

sensory integration ulster university

sensory integration ulster

sensory processing uk

sensory processing under responsive

sensory processing under sensitivity

sensory processing underwear

sensory processing understood

sensory processing unit

sensory integration vs sensory processing

sensory integration vs modulation

sensory integration vestibular

sensory integration video

sensory integration visual activities

sensory integration vestibular activities

sensory integration vestibular dysfunction

sensory integration vision

sensory integration vs aba

sensory integration vestibular proprioception

sensory integration webinar

sensory integration with diverse populations

sensory integration with autism

sensory integration what is it

sensory integration workshop

sensory integration wikipedia

sensory integration weighted blanket

sensory integration work

sensory integration with adults

sensory integration with older adults

sensory integration xyz

sensory integration xi

sensory integration xray

sensory integration yoga

sensory integration youtube

sensory integration york

sensory processing youtube

multisensory integration youtube

sensory integration 2 year old

sensory integration therapy youtube

sensory integration and yoga course

sensory integration disorder 3 year old

sensory integration zebrafish

sensory integration zhongwen

sensory processing zone out

zoloft sensory integration disorder

what's sensory integration

example of sensory integration

best sensory integration books

best sensory activities for autism

best sensory swing for autism

best sensory items for autism

best sensory apps for ipad

best bean bag chairs for sensory integration

best books for sensory integration

how to improve sensory integration

is sensory integration evidence based

best sensory swing for adults

best sensory items for adults

best sensory objects for autism

best sensory kits for toddlers

best sensory toys for kindergarten

best sensory swing for toddlers

best sensory toys for asd

best sensory room ideas

best sensory room items

best sensory rooms

best sensory swing indoor

best sensory videos for newborns

best sensory bins for autism

best sensory items for toddlers

sensory integration for asd

sensory integration for adults with autism

sensory integration for adults with learning disabilities

sensory integration for autistic toddlers

benefits of sensory integration for autism

sensory integration for babies

sensory integration for blind child

sensory integration for balance

brushing techniques for sensory integration

therapy ball for sensory integration

bean bag chair for sensory integration

building blocks for sensory integration

modified clinical test for sensory integration and balance

sensory integration for cerebral palsy

sensory integration for pc

sensory integration for chronic pain

icd 10 code for sensory integration disorder

sensory integration activities for the classroom

sensory integration courses for occupational therapists

icd-10 code for sensory integration disorder of childhood

clinician's guide for implementing ayres sensory integration

sensory integration for down syndrome

sensory integration for dogs

sensory integration for dummies

sensory integration for dyspraxia

icd 10 for sensory integration disorder

sensory integration inventory for individuals with developmental disabilities

different textures for sensory integration

sensory integration therapy for down syndrome

sensory integration for elderly

examples of occupational therapy goals for sensory integration

evidence for sensory integration therapy

suspended equipment for sensory integration

sensory integration explained for parents

sensory integration therapy for elderly

equipment for sensory integration therapy

exercises for sensory integration

vestibular exercises for sensory integration

sensory integration frame of reference for adults

a frame of reference for sensory integration

sensory integration for hand flapping

swing frame for sensory integration

what are sensory integration techniques

sensory integration for geriatrics

sensory integration a guide for preschool teachers

gum chewing for sensory integration

sample occupational therapy goals for sensory integration

song games for sensory integration

sample iep goals for sensory integration

ot goals for sensory integration disorder

sensory integration for hyperactivity

sensory integration for human balance control

the integration site for sensory and motor information in humans is the

sensory integration for mental health

home program for sensory integration

heavy work for sensory integration

how do you test for sensory integration disorder

occupational therapy for kids/specializing in sensory integration

occupational therapy interventions for sensory integration

what is sensory integration therapy for autism

south african institute for sensory integration

interventions for sensory integration

what part of the brain is responsible for sensory integration

clinical test for sensory integration in balance

what is a weighted vest for sensory integration

joint compression for sensory integration

jumping for sensory integration

sensory integration training for speech and language therapists

lap weight for sensory integration

perceptual level for sensory integration

lycra for sensory integration

sercri solutions for sensory integration lda

sensory integration for middle school students

sensory integration for motor planning

areas for interpretation and integration of most sensory information

outcome measures for sensory integration

sensory integration activities for mouth

materials for sensory integration

sensory integration for neuropathy

sensory integration for special needs

other name for sensory integration disorder

another name for sensory integration disorder

sensory integration for ot

sensory integration training for occupational therapists

sensory integration activities for 3 year old

sensory integration for parents

sensory integration for preschool

sensory integration for process

sensory integration therapy for autism pdf

brushing protocol for sensory integration

sensory integration and praxis test for adults

vibration plate for sensory integration

sensory integration for stroke patients

sensory integration questionnaire for parents

the thalamus is responsible for the integration of sensory information

primitive reflexes for sensory integration

reasons for sensory integration disorder

reflex for sensory integration

sensory integration for speech therapy

sensory integration for schizophrenia

swings for sensory integration

sensory integration therapy for schizophrenia

spinning for sensory integration

sensory integration for teachers

sensory integration for trauma

sensory integration for toddlers

sensory integration for therapist

sensory integration training for teachers

sensory integration training for occupational therapists uk

what is sensory integration therapy used for

sensory integration therapy used for autism

what to use for sensory integration disorder

sensory integration therapy for cerebral palsy usa

sensory integration for vestibular

sensory integration for visual impairments

occupational therapy and sensory integration for visual impairment

vibration for sensory integration

vestibular activities for sensory integration

pressure vest for sensory integration

ankle weights for sensory integration

sensory integration therapy for adults with autism

the wilbarger protocol (brushing) for sensory integration

sensory integration therapy for child with autism

sensory integration therapy for adults with dementia

what is the icd 10 code for sensory integration disorder

yoga for sensory integration

what do you do for sensory integration dysfunction

sensory integration ideas

sensory integration for infants

best sensory

what are the best sensory toys for autism

intensive sensory integration therapy

best sensory products

best sensory items

benefits of sensory integration

integration of senses

pros and cons of sensory integration therapy

types of sensory integration therapy

g-sensor sensitivity

best indoor sensory swing

best sensory kits

best proprioceptive toys

sensory integration programs

best sensory room equipment

best sensory integration therapy

best sensory integration courses

best sensory integration tools

sensory-integration therapy

best x axis sensitivity fortnite

best x and y sens fortnite

best z-wave motion sensor

best z-wave sensors

adults with sensory integration disorder

adhd with sensory integration disorder

a child with sensory integration disorder

sensory integration is an evidence-based practice for students with disabilities

how to help child with sensory integration disorder

child with sensory integration disorder

parenting a child with sensory integration disorder

child with sensory integration difficulties

understanding the nature of sensory integration with diverse populations

sensory integration and the perceptual experience of persons with autism

effects of occupational therapy with sensory integration

effects of occupational therapy with sensory integration emphasis

what is sensory integration dysfunction

sensory integration inventory for adults with developmental disabilities

sensory integration therapy for students with autism

how to get diagnosed with sensory integration disorder

how occupational therapy helps with sensory integration issues

activities to help with sensory integration

toys to help with sensory integration

how to work with sensory integration disorder

help with sensory integration

helping child with sensory integration

issues with sensory integration

sensory integration jane ayres

sensory integration theory jean ayres

sensory integration methods

sensory integration with occupational therapy

ot with sensory integration

sensory integration therapy with ot

problems with sensory integration

patients with sensory integration dysfunction

sensory and reflex integration

sensory integration primitive reflexes

sensory integration disorder without autism

sensory integration vs sensory modulation

occupational therapy with sensory integration

sensory integration explained

sensory play with yogurt

sensory enrichment zoo tycoon

sensory friendly zoo lights

sensory processing without autism

sensory disorder without autism

sensory deprivation without tank

sensory issues without autism

sensory integration therapy not evidence based

sensory overload without autism

sensory processing disorder without autism

sensory integration frame of reference occupational therapy

sensory integration therapy for adhd

sensory integration and praxis tests (sipt)

sensory integration clinical observation

sensory integration and praxis tests

sensory integration and trauma

sensory integration ayres

sensory integration activities for autism

sensory integration aba

sensory integration and the child 25th anniversary edition

sensory integration activities for toddlers

sensory integration blessings

sensory integration babies

sensory integration bundy

sensory integration book ayres

sensory integration brushing teeth

sensory processing brain

sensory integration ceu

sensory integration classroom

sensory integration classes

sensory integration child

sensory integration calming techniques

sensory integration cerebral palsy

sensory integration conference

sensory integration clasi

sensory processing cup analogy

sensory processing cartoon

sensory processing cup

sensory integration diet

sensory integration disorder in toddlers

sensory integration disorder vs autism

sensory integration deep pressure

sensory integration delay

sensory processing disorder

sensory processing disorder toddler

sensory processing disorder simulation

sensory processing disorder vs autism

sensory processing disorder in hindi

sensory processing disorder explained

sensory processing disorder tiktok

sensory integration eating

sensory integration evidence

sensory processing explained

sensory integration therapy exercises

sensory integration feeding therapy

sensory integration frame of reference ot

sensory integration food aversions

sensory integration frame

sensory integration feeding

sensory processing from a child's perspective

sensory integration in hindi

sensory integration intervention

sensory integration in school setting

sensory integration ideas for the classroom

sensory integration in speech therapy

sensory integration in the brain

sensory integration in preschool classroom

sensory integration in the child

sensory integration in ot

sensory integration intensive

sensory integration in cerebral palsy

sensory integration lecture

sensory integration motor

sensory integration mouth

sensory integration module 3

sensory integration module 4

sensory motor integration techniques

sensory processing measure

sensory processing measure scoring

sensory processing measure 2

ayres sensory integration and neuroscience

sensory integration olfactory activities

sensory integration outcome measures

sensory integration online course

sensory integration obstacle course

sensory processing occupational therapy

sensory processing overload

sensory processing over responsive

neural integration sensory input

sensory integration physical therapy

sensory integration pyramid of learning

sensory integration practitioner

sensory integration pyramid

sensory integration products

sensory integration premature babies

sensory integration programme

sensory integration process

sensory integration proprioceptive activities

sensory integration powerpoint

sensory integration pathway

sensory integration therapy room

sensory integration session

sensory integration strategies for the classroom

sensory integration screening

sensory integration senses

sensory integration smell

sensory integration sound sensitivity

sensory integration systematic review

sensory integration swing activities

sensory integration speech and language therapy

sensory processing sensitivity

sensory processing sensitivity (sps)

sensory integration therapy for cerebral palsy

sensory integration therapy for sound

sensory integration tactile

sensory integration therapy for autism in tamil

sensory integration therapy in hindi

sensory integration therapy for autism in hindi

sensory integration usmle

sensory integration ultrasound

sensory processing video

sensory integration xbox

sensory integration zen

sensory integration zoo

sensory integration zoom

sensory integration zen den

sensory integration zakir naik