Brainstem auditory evoked response (BAER) is a test to measure the brain wave activity that occurs in response to clicks or certain tones.

How the Test is Performed

You lie on a reclining chair or bed and remain still. Electrodes are placed on your scalp and on each earlobe. The earphones give off a brief click or tone. The electrodes pick up the brain's responses to these sounds and record them. You do not need to be awake for this test.

How to Prepare for the Test

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

How the Test Will Feel

There is little discomfort.

Why the Test is Performed

The test is done to help diagnose nervous system problems and hearing losses (especially in low birth weight newborns), and to assess neurological functions.

Normal Results

The normal range for auditory brain stem values will vary among patients and with the instruments used.

What Abnormal Results Mean

Abnormal test results may indicate a hearing loss, multiple sclerosis, or stroke.

Additional conditions under which the test may be performed:

• Acoustic neuroma
• Brain injury
• Brain malformation
• Brain tumor
• Central pontine myelinolysis
• Speech disorders

This test may also be performed during surgery to decrease the risk of injury to the auditory nerve and the brain.

Risks

There are no risks.

Alternative Names

Evoked auditory potentials; BAEP - brainstem auditory evoked potentials; Evoked response audiometry