Electronystagmography (ENG)

Electronystagmography (ENG)


Procedure overview

What is electronystagmography?

Electronystagmography (ENG) is used to evaluate people with vertigo (a false sense of spinning or motion that can cause dizziness) and certain other disorders that affect hearing and vision. Electrodes are placed at locations above and below the eye to record electrical activity. By measuring the changes in the electrical field within the eye, ENG can detect nystagmus (involuntary rapid eye movement) in response to various stimuli. If nystagmus does not occur on stimulation, a problem may exist within the ear, nerves that supply the ear, or certain parts of the brain. This test may also be used to distinguish between lesions in various parts of the brain and nervous system.

Anatomy of the ear

Anatomy of the ear
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The ear is the organ of hearing. The parts of the ear include:

Different types of ENG tests

The ENG is actually a battery of tests that may include one or more of the following measurements:

Reasons for the procedure

The ENG is used to detect disorders of the peripheral vestibular system (the parts of the inner ear that interpret balance and spatial orientation) or the nerves that connect the vestibular system to the brain and the muscles of the eye.

The test may be performed if an individual is experiencing unexplained dizziness, vertigo, or hearing loss. Additional conditions in which ENG may be performed are acoustic neuroma, labyrinthitis, Usher syndrome, and Ménière’s disease. If a known lesion exists this test can identify the actual site.

There may be other reasons for your doctor to recommend an ENG.

Risks of the procedure

ENG is associated with minimal risks. Some people may experience dizziness or nausea during the test.

ENG should not be used in individuals with pacemakers because the equipment may interfere with pacemaker function.

Back or neck problems may be aggravated by rapid changes in position required for the test.

The water caloric test may produce mild discomfort. Patients who have previously been diagnosed with a perforated tympanic membrane should not undergo the water caloric portion of the ENG test.

There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your doctor prior to the procedure.

Certain factors or conditions may interfere with ENG. These include, but are not limited to, the following:

Before the procedure

During the procedure

An ENG may be performed on an outpatient basis or as part of your stay in a hospital. Procedures may vary depending on your condition and your doctor's practices.

Generally, the ENG follows this process:

  1. If there is wax in the ear, it will be removed.
  2. Before positioning the electrodes, areas of the skin on your face will be cleaned with an alcohol-saturated cotton pad and allowed to air-dry.
  3. A paste will be used to attach the electrodes. One electrode will be positioned in the center of your forehead, and the other electrodes will be positioned above the eyebrow and below the eye in a way that allows you to close your eyes. Electrodes may also be placed to the side of each eye.
  4. Depending on the type of test being performed, you may be asked to look up, down, or to the side or move your head and/or entire body. You may also be asked to close your eyes, which does not hinder the recording of eye movement.
  5. For caloric testing, either air or water will be introduced to the ear while eye movements are recorded.
  6. The electrical activity detected by the electrodes will be fed into a recorder, which amplifies the signal and charts it so that your doctor can interpret the results.

After the procedure

Once the test is complete, the electrodes will be removed and the electrode paste washed off. You may be instructed to avoid rubbing your eyes to avoid spreading the electrode paste.

You will be observed for any signs of weakness, dizziness, and nausea, and may need to lie down or sit for a few minutes to recover.

Your doctor will inform you as to when to resume any medications you stopped taking before the test.

Your doctor may give you additional or alternate instructions after the procedure, depending on your particular situation.

Online resources

The content provided here is for informational purposes only, and was not designed to diagnose or treat a health problem or disease, or replace the professional medical advice you receive from your doctor. Please consult your health care provider with any questions or concerns you may have regarding your condition.

This page contains links to other websites with information about this procedure and related health conditions. We hope you find these sites helpful, but please remember we do not control or endorse the information presented on these websites, nor do these sites endorse the information contained here.

Acoustic Neuroma Association

American Academy of Neurology - Public Education

American Hearing Research Foundation

American Tinnitus Association

Brain Injury Association of America

National Brain Tumor Society

National Institute of Neurological Disorders and Stroke

National Institutes of Health (NIH)

National Library of Medicine

Vestibular Disorders Association


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