BAER - brainstem auditory evoked response
Definition
Brainstem auditory evoked response (BAER) is a test to measure the brain wave activity that occurs in response to clicks or certain tones.
Alternative Names
Evoked auditory potentials; BAEP - brainstem auditory evoked potentials; Evoked response audiometry
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.
Reviewed By: Luc Jasmin, MD, PhD, Departments of Anatomy and Neurological Surgery, University of California, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
