TRIPASS XR تري باس

 

385

Jennie Chung

Susan H. Morgan

54 Neonatal Hearing Screening

A. Purpose

1. To identify hearing loss in the neonatal period in order

to provide early intervention so that delay in speech

and language development may be minimized.

2. To support accurate reporting by state of incidence of

congenital hearing loss.

B. Background

1. The prevalence of congenital hearing loss in newborns

is 1.4 (range 0 to 4.6) per 1,000 infants screened with

97% of newborns screened in the United States (1).

2. The risk of hearing loss can increase substantially

when infants are exposed to certain perinatal risk factors (e.g., cytomegalovirus) or have medical conditions

requiring certain interventions (e.g., extracorporeal

membrane oxygenation) in intensive care nurseries

(Table 54.1).

3. Early intervention for hearing loss can help maximize

the child’s potential (2). Delaying diagnosis of hearing

loss can lead to significant problems in language and

speech acquisition (3).

C. Indications

1. Every newborn should receive a hearing screen before

discharge from the hospital (4,5).

a. Currently, 47 states and the District of Columbia

have passed legislation mandating universal newborn hearing screening for every infant regardless of

background and risk factors (6).

b. Every US state and territory has established an Early

Hearing Detection and Intervention (EHDI) program to help insure infants receive hearing screening and intervention services (7).

c. The Centers for Disease Control and Prevention’s

Early Hearing Detection and Intervention Program

recommends that infants identified by a failed hearing screen be referred for a comprehensive audiology evaluation as soon as possible and always before

3 months of age (8).

2. Infants who meet high-risk criteria for acquiring hearing loss warrant immediate hearing screening, followed

by ongoing monitoring. Table 54.1 lists factors known

to be associated with permanent congenital, late-onset,

or progressive hearing loss in childhood. Even if they

have passed their initial hearing screen, it is critical that

infants with any of these risk factors be referred to audiology after discharge so that they may continue to be

monitored during the early years of language acquisition and development (5).

D. Types of Hearing Loss

1. Conductive: Resulting from impaired sound transmission through ear canal, tympanic membrane, and middle ear

2. Sensorineural: Due to cochlear or retrocochlear

disorder

3. Mixed: Has a both conductive and sensorineural component

4. Auditory neuropathy spectrum disorder: A relatively new

term used to describe auditory characteristics of patients

who exhibit normal cochlear outer hair cell function

but disordered or dyssynchronous neural conduction in

other sites deep to the cochlea along the auditory pathway (9).

E. Types of Hearing Screen

1. Otoacoustic emissions (OAE): A noninvasive screening

tool that measures sounds generated by a functioning

cochlea. A probe containing a miniature microphone

delivers a sound stimulus, either click or tone, into the

ear canal and records the cochlear response that travels

from the cochlea back into the ear canal. This assembly

is coupled to a computer for analysis of the sound in the

ear canal and for processing of the otoacoustic emission. Results may be automatically analyzed and interpreted as either “pass” or “refer” for each ear. Figure

54.1 shows an infant undergoing OAE screening. This

screening tool evaluates the peripheral auditory system

extending to cochlear function.