Hearing Screening Tests for Newborns
It is estimated that serious hearing loss occurs in about 2 to 3 of every 1,000 newborns. Without screening or testing, hearing loss may not be noticed until the baby is more than 1 year old. If hearing loss is not found until later years, the brain's hearing centers will not be properly stimulated. This can affect hearing development, and can delay speech and language. Social and emotional development and success in school may also be affected.
Most hearing loss is congenital (present at birth), but some babies develop hearing loss after they are born. Hearing loss is more likely in premature babies, and babies with infections, respiratory problems requiring long-term use of breathing machines, and certain medications.
Because of these risks, many health organizations now recommend universal infant hearing screening. Today, nearly all newborns are screened for hearing loss, which allows earlier treatment to prevent delays in language and development.
Types of testing
There are 2 types of hearing screening for newborns. They may be done before babies leave the hospital, but should be done before the age of 1 month. These may be used alone or together:
Evoked otoacoustic emissions (EOAE). A test that uses a tiny, flexible plug that is inserted into the baby's ear. Sounds are sent through the plug. A microphone in the plug records the otoacoustic emissions (responses) of the normal ear in reaction to the sounds. There are no emissions in a baby with hearing loss. This test is painless and is usually completed within a few minutes, while the baby sleeps.
Auditory brainstem response (ABR). A test that uses electrodes (wires) attached with adhesive to the baby's scalp. While the baby sleeps, clicking sounds are made through tiny earphones in the baby's ears. The test measures the brain's activity in response to the sounds. As in EOAE, this test is painless and takes only a few minutes.
If the screening test shows a possible hearing loss, further testing is needed. All babies who do not pass the screening test should be checked by an audiologist, a hearing specialist by 3 months of age. Treatment for hearing loss should begin before the baby is 6 months old, an important time for speech and language development.