Infant hearing assessment using Otoacoustic Emission testing

May 15, 2009
OtoacousticIt is an unfortunate fact that hearing-impaired children whose hearing was not assessed at birth may not be correctly identified as having a hearing loss until they are 2 ½ to 3 years of age, sometimes even older.

Delayed language development is often the strongest indicator to parents that something is wrong, but since newborns are not expected to be able to talk, it is very common for parents not to detect congenital hearing impairment in their newborn children. A hearing impairment may have a significant impact on a child’s future. Specifically, an undiagnosed hearing impairment in the first months/years of life may affect the child’s language development, cognitive development, learning skills, behaviour, and socialization.

How audiologists assess an infant’s hearing

The objective of a hearing evaluation is to assess the function of the auditory system. Audiologists select which test procedures to use based on the child’s age or developmental stage. For example, play audiometry, which requires the child to respond to tones by placing a block or small toy into or onto another object, is often used to test children 3 – 5 years of age. Visual reinforcement audiometry, which visually rewards a child for turning his or head toward test tones emanating from speakers placed to the left or right of the child, is usually used to test 1 – 3 year olds. Newborns, however, are too young to participate in play audiometry and visual reinforcement audiometry. Fortunately there is an excellent and objective measurement that can be used to assess their inner ear function.

Otoacoustic Emission (OAE) testing is reliable, rapid, and objectively measures responses from infants. This test involves the presentation of tones through a small earphone placed in the ear canal, and measures the inner ear’s response to those tones. This simple examination takes approximately 30 seconds per ear. If a child fails to show a response, more advanced audiometric testing (ex.: auditory brainstem response audiometry) and a medical examination are required to confirm the presence (and the extent, if any) of the hearing loss. When a hearing impairment is confirmed, the audiologist refers the child and the family to the appropriate medical and rehabilitative resources (ear-nose-throat specialist, audioprosthetist, speech-language pathologist, audiologist in rehab center, early intervention program coordinator) in order to maximize the child’s potential and, if possible, prevent developmental delays.

In summary, an undiagnosed hearing impairment may have serious consequences on your child’s development. Reliable diagnostic procedures and equipment are available to test any child’s hearing (including a newborn’s) so that delays in the child’s development are prevented. Do not hesitate to consult an audiologist if your baby was not screened for hearing impairment at birth, or if you have any concerns about his or her response to sounds or voices.