An EEG or electroencephalogram (e-lek-tro-en-sef-ah-lo-gram) is an
important test that records the electrical activity produced by the billions
of nerve cells in the brain. An EEG gives a physician vital information about
the health and functioning of the brain in order to either make a diagnosis
or monitor ongoing treatment.
This test is useful in diagnosing medical conditions such as seizure
disorders, head injuries, headaches, brain tumors, staring episodes, encephalitis
(brain inflammation) drug overdose, sleep disturbances, and irreversible
brain death. An EEG does not measure intelligence, thoughts or feelings,
nor does the test treat or cure illness. Since it does not send electric
activity into the brain, an EEG cannot give the child a shock.
Brain cells generate electrical impulses that carry messages to and
from all parts of the body through the nervous system. The brain sends out
signals that control breathing, heartbeat, muscle coordination and regulate
body processes such as metabolism and blood sugar levels. Messages are also
sent from one part of the brain to another that control thought, memory,
and other sensory functions.
When a child is healthy, these electrical messages will produce certain
wave patterns. When a child is ill or injured, these electrical signals become
blocked or altered, causing characteristic changes in the brain wave patterns.
These variations are then analyzed to help detect the cause and location
of the problem. It takes a trained specialist, a neurologist, to read the
EEG since all abnormal patterns don't always indicate that there's a problem!
During an EEG, electrodes (kids like to call them "small buttons with
wires") are placed on areas of the child's head with cream (similar to the
electrodes used on the chest during an electrocardiogram). The child is then
asked to lie very still with his/her eyes closed and try to relax. The electrodes
pick up the brain's electrical impulses and sends them to the EEG machine
where they are recorded on a computer or on paper. The test is not painful
and usually takes about 90 minutes.
An EEG recording taken during the sleep state is very helpful since
some abnormal patterns are seen only during sleep. To accomplish this,
the EEG is often scheduled during young children's normal nap time. For older
youngsters, parents are instructed to keep their child up several hours past
their normal bedtime and wake up 3-4 hours earlier than usual. This causes
the child to be sleepy during the procedure instead of using medication (sedation
can interfere with the brain patterns).
Each EEG lab has its own sent of instructions for parents to follow
prior to having the test done on your child. In general, you can prepare
your child by:
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Explaining the test to your child.
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Shampooing your child's hair the night before the test. Do not use
any hair spray, oil or mousse.
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Allowing the child to eat and/or drink as usual
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Having the child take his or her usual prescribed medications. (Always
let the EEG technician know what medication your child is taking)
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Bringing your child's favorite toy and/or security item such as a
blanket.
During the test, if your child is old enough, he or she may be asked
to breathe rapidly and deeply for a few minutes. In addition, a flashing
strobe light may be placed in front of your child's eyes. These procedures
activate certain brain wave patterns that are useful for a diagnosis. Younger
children may be held by their parents during the test in order to get a better
recording.
After the EEG, the electrodes are removed and a wet wash cloth is
used to clean the hair and scalp Once home, your child can resume his/her
normal activities. A neurologist, a doctor who specializes in the nervous
system, will read the tracing and send a report to the child's pediatrician.
Results from the test are usually in the hands of the referring physician
within 5-7 days, or sooner, if the reason for the test was urgent.
