Brainstem auditory evoked response (BAER) is a test to measure the brain wave activity that occurs in response to clicks or certain tones.
You lie on a reclining chair or bed and remain still. Electrodes are placed on your scalp and on each earlobe. A brief click or tone will be transmitted through earphones you are wearing during the test. The electrodes pick up the brain's responses to these sounds and record them. You do not need to be awake for this test.
You may be asked to wash your hair the night before the test.
Young children often need medicine to help them relax (sedation) so they can stay still during the procedure.
The test is done to:
This test may also be performed during surgery to decrease the risk for injury to the hearing nerve and brain.
Normal results vary. Results will depend on the person and the instruments used to perform the test.
Abnormal test results may be a sign of hearing loss, multiple sclerosis, acoustic neuroma, or stroke.
Abnormal results may also be due to:
There are no risks associated with this test.
Reviewed By: Josef Shargorodsky, MD, MPH, Johns Hopkins University School of Medicine, Baltimore, MD. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.