Hearing Exams in Newborns and Infants
According to the Early Hearing Detection & Intervention (EHDI) Program of the Centers for Disease Control and Prevention (CDC), more than 12,000 infants with impaired hearing are born each year in the United States. Because early diagnosis and intervention are important to insure normal development, most newborns undergo hearing tests before leaving the hospital. This testing program is called Universal Newborn Hearing Screening (UNHS).
Hearing testing in newborns and infants includes otoacoustic emissions (OAEs) tests and auditory brainstem response (ABR) tests. In many cases, these painless tests can detect even mild hearing impairment.
During normal hearing, sound waves that reach the cochlea cause tiny hair-like cells to vibrate, creating inaudible sounds called otoacoustic emissions. In otoacoustic emissions testing, a small probe is inserted into the ear canal and used to detect these inaudible sounds. This test can be used to diagnose hearing impairment caused by conditions that affect the outer ear, the middle ear, and the outer hair-like cells in the cochlea.
An auditory evoked response is an involuntary response to sound that occurs in the auditory system (e.g., inner ear, auditory nerve, brainstem). Auditory brainstem response is a type of auditory evoked response that starts in the auditory nerve. This response can be evaluated using a non-invasive test called an electroencephalogram (EEG or brain wave test).
In this test, electrodes (small disks) are placed on the head and attached by wires to a machine that detects and records brain wave activity in response to sound. Electrical signals from the brain are converted into wavy lines on a moving sheet of graph paper. ABR can detect hearing impairment caused by abnormal function of the cochlea, auditory nerve, or brainstem.
When otoacoustic emissions or auditory brainstem response testing indicates hearing impairment, follow-up testing is required. If further tests confirm the results, the infant should be evaluated by an audiologist (hearing specialist) by 3 months of age. Infants with suspected hearing impairment and infants who are at increased risk require regular (e.g., every 6 months) follow-up care.
The CDC reports that pediatricians can and should play a major role in the care of infants who do not pass newborn hearing screening. It's important for these infants to be identified and receive follow-up treatmentre-screening, a comprehensive audiologic evaluation, and/or therapeutic services.
Updated by Remedy Health Media