Audiogram & ENG
Also known as: Electronystagmogram/audiogram
(ENG)
What is it?
An audiogram is a hearing test that checks how well a
person can hear pure tones in each ear. ENG stands for
electronystagmogram, which is a test of the balance
mechanism of the inner ear. ENG may also be referred to as
caloric stimulation.
Who needs this procedure?
An audiogram provides the most accurate diagnosis of
most hearing problems. It is used to identify the presence
of hearing loss, as well as the cause. ENG is performed to
check for damage to the acoustic nerve, located in the
inner ear where it provides hearing and helps with
balance. An ENG might be recommended when an audiogram
shows hearing loss, when a patient experiences frequent
vertigo (a false sensation of movement or spinning), or to
test for brain damage in comatose patients.
How do I prepare for this procedure?
There are no special preparations for an audiogram. If
you are having an ENG, your doctor will recommend that you
avoid alcohol and caffeine for at least 24 hours before
the test, and refrain from eating any heavy meals just
prior to the test. Your doctor will also give you
instructions for the types of medications you can and
cannot take before this test.
How is this procedure performed?
An audiogram is performed by a hearing specialist
called an audiologist. You will sit in a special
soundproof testing booth with earphones on your head. The
audiologist will transmit sounds through the earphones,
testing each ear separately. You will be asked to indicate
when you hear a sound, and in which ear. This is called
air conduction hearing. With the earphones removed, the
audiologist will test bone conduction hearing by holding a
vibrating instrument against the bone behind your ear.
Both tests are painless. With an electronystagmogram
(ENG), first cool, then warm liquid is run through a
special tube into the ear canal. The change in temperature
stimulates the inner ear, which causes the eyes to move
rapidly. This reflexive, or involuntary, movement is
called nystagmus. A study of the eye movements in response
to the change in temperature indicates how well the inner
ear’s balance mechanism is working. You may find that you
experience severe vertigo during the ENG. This feeling
should pass quickly.
What can I expect after the procedure?
Audiogram results are usually shown in graph form. The
audiologist will explain the results to you, and show you
how to read the graph. The results of the ENG will be used
to determine a treatment plan. You should experience no
side effects from either test. Report any continued or
severe vertigo to your doctor.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
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