Ask the Medical Experts
Gail Linn, Au.D., Potomac Audiology
I recently heard of a baby being diagnosed with a hearing loss. How do you test babies and young children?
Luckily we have a battery of tests that can be used for testing infants, children and individuals that cannot participate in a hearing test for one reason or another. Two important tests are:
Otoacoustic Emissions: This is a non-invasive test that allows a tester to present a click or tone stimulus to an ear and measure back a response. The click presents a broad band of frequencies to the cochlea and an echo is measured in response. The echo that is measured helps determine if the baby has normal or near normal cochlear function and rules out moderate to profound hearing loss. This test is performed in most hospitals at the time of birth.
Auditory Brainstem Response: During this test electrodes are placed on the head and sound is delivered to the eighth auditory nerve. The electrodes allow the machinery to measure those sounds as they travel through the nerve and system. If the sound can be measured when it is very soft, 25 dB or less, then normal hearing in that frequency is assumed. Using this method, audiologists are able to get a good idea of the softest sound that can be heard in a variety of frequencies or pitches. Previously the person being tested had to be extremely quiet for the test to be effective. This meant that many children had to be sedated which always has a risk factor. Recent advances in technology allow the test to be given without sedation.
Testing children takes a great deal of time, skill, patience and experience. Because of this, finding a Pediatric Audiologist can be difficult. A number of the audiology training programs have incentives for students to pursue Pediatric Audiology.