Electronystagmography (ENG) testing

Diagnostic tests such as electronystagmography (ENG) help Advocate Health Care’s team of audiologists check for possible inner ear and balance problems. An ENG is used to find the cause of vertigo, involuntary eye movements (nystagmus), balance disorder and dizziness so you can get the best treatment possible.

What is an electronystagmography test?

ENG measures involuntary eye movements, known as nystagmus, to assess the functionality of the vestibular (balance) system and certain neurological functions.

The vestibular system is responsible for maintaining balance and spatial orientation, which is the natural ability to understand the direction of objects (forward or backward, right or left and above or below).

How an ENG test works

ENG testing typically takes 90 minutes and involves small electrodes. Your audiologist will attach the electrodes around your eyes to monitor and record the electrical activity of the eye muscles during a series of maneuvers that include:

• Following a visual target with your eyes
• Introducing warm or cold air or water into the ear canal to stimulate the inner ear, causing eye movements
• Moving your head into various positions to assess uncontrolled eye movements associated with changes in head position

The electrodes pick up the signals generated by the eye movements and send the findings to a computer. The signals are then analyzed by your provider to pinpoint the characteristics of nystagmus.

While ENG provides accurate measurements of eye movements, the use of electrodes may introduce some limitations. The electrodes can be sensitive to movement and the setup process may take more time.

What’s the difference between electronystagmography (ENG) and videonystagmography (VNG)?

There are other methods for checking vestibular function, such as videonystagmography (VNG) and rotary chair testing, which may offer similar information but use different technologies.

ENG uses electrodes attached around the eyes to record electrical impulses generated by eye movements to perform an electronystagmography.

VNG, on the other hand, uses infrared video cameras to record eye movements. Small cameras are placed near the eyes to visually capture and record the movements. VNG is typically more comfortable for patients since it involves video goggles or cameras without electrodes.

Both ENG and VNG are both valuable tests for assessing vestibular function and diagnosing disorders related to balance and spatial orientation. The choice between the two often depends on your doctor’s preferences, equipment availability and your specific situation.

Why you might need an electronystagmography

ENG is often used to diagnose and evaluate disorders of the inner ear, vestibular nerve and central nervous system. Some common reasons your doctor might recommend an ENG test include:

• Assessment of vestibular function: ENG can provide information about how well the vestibular system is functioning. This includes assessing the response to head movements, changes in body position and other stimuli that may provoke nystagmus.
• Dizziness and vertigo: ENG provides inner ear testing to determine whether the symptoms are related to benign paroxysmal positional vertigo (BPPV), labyrinthitis or Meniere's disease.
• Evaluation of involuntary eye movements (nystagmus): Electronystagmography is particularly effective in recording and analyzing involuntary eye movement patterns, which helps your doctor diagnose specific conditions.
• Monitoring treatment progress: In some cases, ENG testing may be used to monitor the effectiveness of treatments for vestibular disorders.
• Unexplained balance Issues: If a person is experiencing difficulties with balance without an obvious cause, ENG can be used to assess the vestibular system and identify potential underlying issues.

Preparing for your electronystagmography test

If your provider recommends an ENG test, they will give you instructions on how to get ready for your test. Some general guidelines that may help you prepare include:

• Don’t drink alcohol or caffeine before the test
• Tell your doctor what medications you are taking as they may ask you to stop taking them temporarily prior to testing
• Don’t wear makeup or jewelry
• Plan ahead and have a ride to and from the testing facility

Your specific instructions may vary depending on your provider and the testing facility.

Risks of an electronystagmography test

There are minimal risks with an electronystagmography test. Some people experience nausea and dizziness. Other risks include:

• Water from the caloric test may cause mild discomfort. If you’ve been diagnosed with a perforated tympanic membrane, you should not do the water caloric portion of the test.
• Neck or back problems may be aggravated by changes in the position needed for testing.

Discuss any concerns with your doctor prior to your test.