How Do You Test a Baby’s Hearing?
That’s a good question! Newborn infants now have their hearing screened after being born, before discharge from the hospital. A newborn hearing screening is conducted using one of two tests, either an auditory brainstem response (ABR) test or an otoacoustic emission (OAE) test. Both are computerized tests that do not require a behavioral response from the infant and only take a few minutes to complete if the baby is relatively quiet.
An ABR test involves delivering a soft sound into the ear using a small tip and placing some electrodes (stickers) around the ears and forehead. The electrodes measure how the hearing nerve for each ear responds to sound. With an OAE test, a small tip is placed in the ear and a computerized sound is generated into the ear canal. An echo or a response from microscopic cells that line the inner ear is recorded. This cellular response is recorded and is used to determine if the inner ear cells for hearing are functioning normally or if they may be damaged.
If an infant does not pass an ABR hearing screening or an OAE hearing screening their hearing may be rescreened a second time, preferably within a few weeks of discharge from the hospital. If they do not pass the second screening then a diagnostic hearing test should be scheduled, ideally prior to 3 months of age.
A diagnostic hearing test is completed using a combination of ABR and OAE tests however takes longer than a screening and gives more specific information regarding hearing sensitivity.
OAE and ABR testing are sometimes conducted on older children and perhaps adults. Both tests provide useful, objective diagnostic information regarding hearing sensitivity without the need for a behavioral or subjective response from the person being tested.