Brainstem Auditory Evoked Response Test
Alternate Names : BAER Test, Auditory Brain Stem Response, ABR, Evoked Response Audiometry
The brainstem auditory evoked response test, or BAER, helps evaluate the following:
hearing, or auditory, structures in the brain
how well a person hears
During this test, clicking noises stimulate the hearing nerves that run between the ear and the brain. Electrodes are attached to the scalp and ear lobes to record tiny changes in brain waves from these sounds. These changes appear on a graph as peaks, or highs, and troughs, or lows.
Because the response to BAER is involuntary, this test is used to check hearing in those who cannot respond or cooperate, such as babies, young children, and people in comas. It is also helpful in determining whether certain hearing problems are physical or psychological.
Who is a candidate for the test?
The test may be done on newborns to check hearing. It may also be used when a person shows the following signs:
a balance disorder, such as Meniere disease
a brain tumor that affects hearing
certain conditions that attack the nerves, such as multiple sclerosis
hearing impairments or deafness
hearing nerve damage
a stroke that affects hearing
How is the test performed?
Usually the test takes less than 30 minutes. A healthcare provider may perform the test in an office, clinic, or hospital. Often, a person sits up for this test. Dabs of ointment are applied at certain spots on the person's scalp and each ear lobe. Electrodes are placed on these spots. As earphones deliver clicks to each ear, brain waves sensed by the electrodes are graphed.