What It Is
An electroencephalogram (EEG) is a test used to detect
abnormalities related to electrical activity of the brain. This
procedure tracks and records brain wave patterns. Small metal discs
with thin wires (electrodes) are placed on the scalp, and then send
signals to a computer to record the results. Normal electrical
activity in the brain makes a recognizable pattern. Through an EEG,
doctors can look for abnormal patterns that indicate seizures and
other problems.
Why It's Done
The most common reason an EEG is performed is to diagnose and
monitor seizure disorders. EEGs can also help to identify causes of
other problems such as sleep disorders and changes in behavior.
EEGs are sometimes used to evaluate brain activity after a severe
head injury or before heart or liver transplantation.
Preparation
If your child is having an EEG, preparation is minimal. Your
child's hair should be clean and free of oils, sprays, and
conditioner to help the electrodes stick to the scalp.
Your doctor may recommend that your child stop taking certain
medications before the test that can alter results. It's often
recommended that kids avoid caffeine up to 8 hours before the test.
If it's necessary for your child to sleep during the EEG, the
doctor will suggest ways to help make this easier.
The Procedure
An EEG can either be performed in an area near the doctor's
office or at a hospital. Your child will be asked to lie on a bed
or sit in a chair. The EEG technician will attach electrodes to
different locations on the scalp using adhesive paste. Each
electrode is connected to an amplifier and EEG recording
machine.
The electrical signals from the brain are converted into wavy
lines on a computer screen. Your child will be asked to lie still
because movement can alter the results.
If the goal of the EEG is to mimic or produce the problem your
child is experiencing, he or she may be asked to look at a bright
flickering light or breathe a certain way. The health care provider
performing the EEG will know your child's medical history and
will be prepared for any issues that may arise during the test.
Most EEGs take about an hour to perform. If your child is
required to sleep during it, the test will take longer. You
might be able to stay in the room with your child, or you can step
outside to a waiting area.
What to Expect
An EEG isn't uncomfortable and patients do not feel any
shocks on the scalp or elsewhere; however, having electrodes pasted
to the scalp can be a little stressful for kids, as can lying still
during the test.
Getting the Results
A neurologist (a doctor trained in nervous system disorders)
will read and interpret the results. Though EEGs vary in complexity
and duration, results are typically available in several days.
Risks
EEGs are very safe. If your child has a seizure disorder, your
doctor might want to stimulate and record a seizure during the EEG.
A seizure can be triggered by flashing lights or a change in
breathing pattern.
Helping Your Child
You can help prepare your child for an EEG by explaining that
the test won't be uncomfortable. You can describe the room and
the equipment that will be used, and reassure your child that
you'll be right there for support. For older kids, be sure to
explain the importance of keeping still while the EEG is done so it
won't have to be repeated.
If You Have Questions
If you have questions about the EEG procedure, speak with your
doctor. You can also talk to the EEG technician before the
exam.
Reviewed by:
Kate M. Cronan, MD
Date reviewed: September 2008
Note: All information is for educational purposes only. For specific medical advice,
diagnoses, and treatment, consult your doctor.
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