what is an eeg? - Marquette General Hospital

This pamphlet has been designed by the
health care professionals of Marquette
General Health System to provide you with
information on:
• what an EEG (Electroencephalogram)is.
• what information an EEG provides to the
doctor.
• what can be expected before, during, and
after an EEG.
We hope you will find this information helpful
and informative.
WHAT IS AN EEG?
The word electroencephalogram means
brain writing. The brain is made up of millions
of nerve cells that give off electrical
energy. During an EEG, electrodes pick up
the brain’s electrical impulses and carry
them to a computer where their pattern is
recorded as waves.
WHAT DOES THE
TEST TELL US?
The EEG can provide your doctor with
valuable clues to the causes of headaches,
seizures, or other puzzling problems. It
is also used to evaluate infections of the
nervous system, strokes, tumors, and the
growth and development of the nervous
system in babies, children, and adults. The
EEG does not record thoughts or measure
intelligence.
WHAT PREPARATION
IS NECESSARY?
Wash your hair the night before the test.
Do not use any hair care products after
shampooing.
If you are taking any medication,
continue to do so and inform the staff.
Eat normally, avoid caffeinated drinks.
You may be asked to avoid sleep the
night before the test. If so, do not drink
caffeinated beverages such as coffee, tea,
or soft drinks. Do not take tablets made to
keep you awake.
WHAT HAPPENS
DURING THE TEST?
The neurophysiology technician
will measure your head, clean your skin
with a mild abrasive, and apply small metal
discs (electrodes) to your scalp with a
paste. Other electrodes may be applied to
your chest, face, or arms to monitor movement
and/or other electrical impulses
such as your heart beat.
You will sit in a comfortable chair
or recliner while the recording is made.
If you start to fall asleep, the tech may
awaken you.
Activating procedures may be used
such as having you breathe deeply (hyperventilation)
or look at a flashing light
(photic stimulation). The machine will
pick up any movement so you must keep
your head still.
If the test is being done on your baby
or your child, it may help to bring along a
bottle, a blanket or a favorite toy.
The test will take about one hour.
It is painless and safe. You will not receive
any electrical shock.

HEALTH INFORMATION
If you are asked to avoid sleep, you
may be excessively sleepy after the test.
Please arrange to have someone d r i v e
you home if you are an outpatient.
If your child is being tested, ask if the
test can be scheduled during nap time.
AFTER YOUR TEST
You may find some of the following
hints helpful in removing the paste used
to attach the electrodes to your scalp.
QUESTIONS
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PAMPHLET
E.E.G
Electroencephalogram
• Comb or brush hair to remove flakes
or paste.
• Depending on the paste used, nail
polish remover may be needed to dissolve
any residue.
• Shampoo.
• The technologist will give you
additional instructions on paste
removal.
The paste residue will not show up
on x-ray and this will not interfere with
other tests.
You can get the results of your EEG
from your doctor, who will receive a
report in 2-3 days.
Additional health information is available
through the MGH Health Information Center
(906) 225-4950
or 1-800-562-9753, ext. 4950
© 1983 Marquette General Hospital, Inc.
REVISED—SEPTEMBER—2004