Electronystagmography is a test that looks at eye movements to see how well two nerves in the brain are working. These nerves are:
Vestibular nerve (eighth cranial nerve), which runs from the brain to the ears
Oculomotor nerve, which runs from the brain to the eyes
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How the Test is Performed
Patches called electrodes are placed above, below, and on each side of your eyes. They may be sticky patches or attached to a headband. Another patch is attached to the forehead.
The health care provider will spray cold water or air into each ear canal at separate times. The patches record eye movements that occur when the inner ear and nearby nerves are stimulated by the water or air. When cold water enters the ear, you should have rapid, side-to-side eye movements called nystagmus.
Next, warm water or air is placed into the ear. The eyes should now move rapidly toward the warm water then slowly away.
You may also be asked to use your eyes to track objects, such as flashing lights or moving lines.
The test takes about 90 minutes.
How to Prepare for the Test
Most of the time, you do not need to take special steps before this test.
Your provider will tell you if you need to stop taking any medicines before you have this test.
DO NOT stop or change your medicines without talking to your provider first.
How the Test will Feel
You may feel discomfort due to cold water in the ear. During the test, you may have:
Nausea or vomiting
Brief dizziness (vertigo)
Why the Test is Performed
The test is used to determine whether a balance or nerve disorder is the cause of dizziness or vertigo.
You may have this test if you have:
Dizziness or vertigo
Possible damage to the inner ear from certain medicines
Certain eye movements should occur after the warm or cold water or air is placed into your ears.
Note: Normal value ranges may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
What Abnormal Results Mean
Abnormal results may be a sign of damage to the nerve of the inner ear or other parts of the brain that control eye movements.
Any disease or injury that damages the acoustic nerve can cause vertigo. This may include:
Blood vessel disorders with bleeding (hemorrhage), clots, or atherosclerosis of the blood supply of the ear
Amit M. Shelat, DO, FACP, FAAN, Attending Neurologist and Assistant Professor of Clinical Neurology, Stony Brook University School of Medicine, Stony Brook, NY. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.