Test Overview

An electronystagmogram (ENG) measures normal
eye movement and involuntary rapid eye movements called
nystagmus. It also checks the muscles that control eye
movements. ENG checks how well the eyes,
inner ears, and brain help you keep your balance and position (such as when
you change from lying down to standing).

ENG is done to help see
whether there is damage or a problem in how the inner ear, brain, or nerves
connecting them work. These problems may cause
dizziness,
vertigo, or loss of balance.

Nystagmus
occurs normally when the head is moved. But nystagmus without moving your head
or nystagmus that does not go away may be caused by conditions that affect the
inner ear, brain, or the nerves connecting them.

During ENG,
electrodes are attached to the face near the eyes to record eye movements. The
movements are recorded on graph paper. A series of recordings is done.

  • Baseline recordings are taken with your head at rest.
  • More recordings are done:
    • While you move your head up and down, left and right.
    • While you look at a moving object.
    • After warm or cold water (or air) is placed inside your
      ears.

Why It Is Done

An electronystagmogram (ENG) is done
to:

  • Find where the problem is in the inner ear, brain, or nerves
    connecting them that is causing dizziness, vertigo, or a loss of
    balance.
  • Find any damage to structures or nerves in the inner ear, brain,
    or nerves connecting them.

How To Prepare

For 2 to 5 days before the test, you
will be asked to stop taking:

  • Medicines that help your vertigo.
  • Sedatives and tranquilizers.
  • Drinks with alcohol.
  • Foods that contain caffeine, such as coffee, tea, cola, and
    chocolate.

Your doctor may ask you to eat a light meal or not eat for
3 to 4 hours before the test, because the test can cause nausea and
vomiting.

Do not wear facial makeup during the test so the
electrodes can attach to the skin.

If you normally wear glasses,
contact lenses, or hearing aids, bring them to the test.

If you have
a neck or back problem, tell your doctor, so your neck and back will be
protected during the test.

How It Is Done

An electronystagmogram (ENG) may be done
in a hospital or in a doctor’s office by a doctor or hearing specialist (audiologist).

Before the test begins,
your eyes and ears will be checked. Any earwax in your ear canal will be
removed.

Five electrodes will be attached with a special paste to
your face. You will be in a dark room for the test. The test may have six
parts.

  • To find the right settings for the measuring tool, you will
    follow a moving point of light with only your eyes. You should not move your
    head during this part of the test.
  • Readings will be taken with your eyes closed. You may be given a
    mental task to do, such as an arithmetic problem, during this part of the test.
    Readings will be taken while you look straight ahead and to each side.
  • Readings will be taken while your eyes follow the back-and-forth
    movement of a pendulum.
  • Readings will be taken while you follow a series of moving
    objects out of your line of vision. As each object leaves your line of vision,
    you will be asked to look immediately at the next moving object.
  • Readings will be taken while you move your head from side to side
    and up and down. You may be asked to move your body (as well as your head) into
    different positions.
  • Near the end of the test, your eye movements may be recorded
    while cool and warm water is placed inside your ears. In some cases, warm and
    cool air may be blown gently into your ears instead of using water. This part
    of the test is called the caloric test and may be done without using electrodes
    near your eyes. The caloric test is not done if you have a perforated eardrum,
    because water used in the caloric test can get into the middle ear and lead to
    infection. The caloric test can be done with air instead of water, but if the
    eardrum is perforated, the caloric test may not be done at all.

The test may take 60 to 90 minutes.

How It Feels

You may feel weak, dizzy, or nauseated
during an electronystagmogram. You may feel as if you are going to fall down
during the test, but don’t worry-the doctor or audiologist will make sure you
do not fall. These feelings will go away when the test is done.

If you are having the test because you have dizziness or vertigo, you may find
that the test causes your condition to be worse for a short time.

During the caloric test, you may feel nauseous and may vomit. You may
need to lie down until the nausea and vomiting or vertigo pass.

Risks

An electronystagmogram may cause vomiting. There
is a small chance of causing a neck or back problem to get worse during the
test because of the quick body movements that are done.

Results

An electronystagmogram (ENG) measures
normal eye movement and involuntary rapid eye movements called
nystagmus. It also checks the muscles that control eye
movements. ENG checks how well the eyes,
inner ears, brain, and nerves connecting them help you keep your balance and
position (such as when you change from lying down to standing). Results are
recorded as normal or abnormal.

Normal

Test results are normal if there are no
abnormal involuntary eye movements during the test. Some nystagmus occurs
normally when you turn your head.

Results of the caloric test are
normal if involuntary eye movements have normal direction and intensity.

Abnormal

Test results are abnormal if there is
nystagmus with head-turning that does not go away in a specific or normal
length of time. The results of the caloric test are abnormal if there are fewer
eye movements or no eye movement during the test. Abnormal results may:

What Affects the Test

Reasons you may not be able to
have the test or why the results may not be helpful include:

  • Taking some medicines, such as stimulants (including caffeine),
    depressants,
    sedatives, and medicines to help vertigo.
  • Too many movements of the head or other eye movements, such as
    blinking.
  • Not being able to do what is asked during the test. Medical
    conditions that affect attention, poor eyesight, or cause sleepiness can affect
    the test results.

What To Think About

  • At some centers you can’t have an electronystagmogram if you
    have a pacemaker because the tool that measures eye movements can affect
    pacemaker function.
  • Because an electronystagmogram can’t find some inner ear
    problems, a normal result does not mean an inner ear condition is not
    present.
  • To check for hearing loss or
    tinnitus, other tests such as audiometry or an auditory brain stem response (ABR) test may be done. If a tumor or stroke is
    suspected in a certain part of the brain, a
    CT scan or
    MRI may be used to confirm the diagnosis.

References

Other Works Consulted

  • Chernecky CC, Berger BJ (2013). Laboratory Tests and Diagnostic Procedures, 6th ed. St. Louis: Saunders.
  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
  • Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby Elsevier.

Credits

ByHealthwise Staff
Primary Medical Reviewer Anne C. Poinier, MD – Internal Medicine
Specialist Medical Reviewer Karin M. Lindholm, DO – Neurology

Current as ofOctober 9, 2017