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.
Young children often require some type of sedation (medicine to relax them) so they remain still during the procedure.
Why the test is 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.
Normal results vary, and depend on the patient and the instruments used to perform the test.
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.