The brainstem auditory evoked response (BAER) test measures responses in brain waves that are stimulated by a clicking sound to check the central auditory (hearing) pathways of the brainstem.

You lie on a reclining chair or bed and remain still. Electrodes are placed on your scalp and on each earlobe. You hear clicking noises or tone bursts through earphones, and the electrodes pick up the brain's response and record it on a graph.

You may be asked to wash your hair the night before the test.

Infants and children:

The preparation you can provide for this test depends on your child's age and experience. For general information regarding how you can prepare your child, see the following topics:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

There is little discomfort.

The test is performed to help diagnose nervous system abnormalities, hearing losses (especially in low-birth-weight newborns), and to assess neurologic functions.

The auditory brain stem values are in a normal range. This range varies among patients and instruments used.

Abnormal findings may indicate a hearing loss, multiple sclerosis, or a cerebrovascular accident (stroke).

Additional conditions under which the test may be performed:

• Acoustic neuroma
• Central pontine myelinolysis

There are no risks.