BAER - brainstem auditory evoked response

Alternative Names: Evoked auditory potentials; Brainstem auditory evoked potentials; Evoked response audiometry; Auditory brainstem response; ABR; BAEP

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

Why is the Test Performed?

The test is done to:

• Help diagnose nervous system problems and hearing loss (especially in newborns and children)
• Determine how well the nervous system works

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

How is the Test 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.

Preparation for the Test

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

Young children often require some type of sedation (medicine to relax them) so they remain still during the procedure.

BAER - brainstem auditory evoked response Risks

There are no risks.

Normal Results for BAER - brainstem auditory evoked response

Normal results vary, and depend on the patient and the instruments used to perform the test.

What Abnormal Results Mean

Abnormal test results may be a sign of hearing loss, multiple sclerosis, acoustic neuroma, or stroke.

Abnormal results may also be due to:

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

Brain	Brain wave monitor

Review Date: 8/3/2010
Reviewed By: Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; Seth Schwartz, MD, MPH, Otolaryngologist, Virginia Mason Medical Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

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