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BAER - brainstem auditory evoked response
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.
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. 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.
How to Prepare for the 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.
Why the Test is Performed
The test is done to:
- Help diagnose nervous system problems and hearing loss (especially in newborns and children)
- Find out how well the nervous system works
- Check hearing ability in people who cannot do other hearing tests
This test may also be performed during surgery to decrease the risk for injury to the hearing nerve and brain.
Normal Results
Normal results vary. Results will depend on the person 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.
Hearing loss
Hearing loss is being partly or totally unable to hear sound in one or both ears.
Multiple sclerosis
Multiple sclerosis is an autoimmune disease that affects the brain and spinal cord (central nervous system).
Acoustic neuroma
An acoustic neuroma is a slow-growing tumor of the nerve that connects the ear to the brain. This nerve is called the vestibular cochlear nerve. It...
Abnormal results may also be due to:
- Brain injury
- Brain malformation
- Brain tumor
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Central pontine myelinolysis
Central pontine myelinolysis
Central pontine myelinolysis is brain cell dysfunction. It is caused by the destruction of the layer (myelin sheath) covering nerve cells in the mid...
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Risks
There are no risks associated with this test.
References
Brown CJ, Johnson TA. Electrophysiologic assessment of hearing. In: Flint PW, Haughey BH, Lund V, et al, eds. Cummings Otolaryngology: Head & Neck Surgery . 6th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 134.
Hahn CD, Emerson RG. Electroencephalography and evoked potentials. In: Daroff RB, Jankovic J, Mazziotta JC, Pomeroy SL, eds. Bradley's Neurology in Clinical Practice . 7th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 34.
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Brain - illustration
The major areas of the brain have one or more specific functions.
Brain
illustration
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Brain wave monitor - illustration
The brainstem auditory evoked response test (BAER), is performed to help diagnose nervous-system abnormalities, hearing losses (especially in low-birth weight newborns), and to assess neurologic functions. The test focuses on changes and responses in brain waves. The brain waves are stimulated by a clicking sound to evaluate the central auditory pathways of the brainstem.
Brain wave monitor
illustration
-
Brain - illustration
The major areas of the brain have one or more specific functions.
Brain
illustration
-
Brain wave monitor - illustration
The brainstem auditory evoked response test (BAER), is performed to help diagnose nervous-system abnormalities, hearing losses (especially in low-birth weight newborns), and to assess neurologic functions. The test focuses on changes and responses in brain waves. The brain waves are stimulated by a clicking sound to evaluate the central auditory pathways of the brainstem.
Brain wave monitor
illustration
Review Date: 5/25/2016
Reviewed By: Sumana Jothi, MD, specialist in laryngology, Assistant Clinical Professor, UCSF Otolaryngology, NCHCS VA, SFVA, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
