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Electroencephalogram (EEG): About Your Child's Test

What is it?

An electroencephalogram (EEG) lets a doctor see the electrical activity of your child's brain.

Your child will have small pads or patches attached to different places on his or her head. These are called electrodes. Wires connect the electrodes to a computer.

The computer records the activity of the brain. This looks like wavy lines on the computer screen or on paper.

Why is this test done?

The test is often used to diagnose epilepsy. It helps a doctor know what types of seizures a child is having.

An EEG can also check brain activity in people with sleep disorders.

It can also help a doctor know why a person passed out (lost consciousness).

How do you prepare for the test?

  • An EEG can be scary for a child. The testing room will have unfamiliar equipment in it, and wires will be attached to your child's head. Reassure your child that the test doesn't hurt. Tell him or her that you will be nearby at all times.
  • Tell your doctor if your child is taking any medicines. Your doctor may ask that your child stop taking certain medicines before the test. These include sedatives and medicines used to treat seizures.
  • Do not give your child anything with caffeine in it for 12 hours before the test. This includes cola, energy drinks, and chocolate.
  • Shampoo your child's hair and rinse with clear water the evening before or the morning of the test. Do not put any hair conditioner or oil on the hair after you wash it.
  • Your doctor may ask that your child not sleep the night before the test. Or the doctor may ask that your child not nap before the test. This is because some types of brain activity can only be seen when your child is asleep.

How is the test done?

  • Your child will lie on his or her back on a bed or table. Or your child might relax in a chair with eyes closed.
  • A technologist will attach the electrodes to different places on your child's head. Or your child might get a cap with fixed electrodes on it.
  • Your child will lie still with eyes closed. He or she will be told not to talk unless it's needed.
  • The technologist may ask your child to:
    • Breathe deeply and rapidly. This is called hyperventilating.
    • Look at a bright, flashing light called a strobe.
    • Go to sleep. If your child can't fall asleep, he or she may get medicine to help.

What are the risks of the test?

  • There is no pain. No electrical current goes through your child's body.
  • If your child has a seizure disorder such as epilepsy, the flashing lights or hyperventilation may cause a seizure. The technologist is trained to take care of your child if this happens.

How long does the test take?

The test will take about 1 to 2 hours.

What happens after the test?

  • Your child will probably be able to go home right away.
  • Your child can go back to his or her usual activities right away.

When should you call for help?

Watch closely for changes in your child's health, and be sure to contact your doctor or nurse advice line if:

  • Your child has any problems that you think may be from the test.
  • You have any questions about the test or have not received your child's results.

Follow-up care is a key part of your child's treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if your child is having problems. It's also a good idea to keep a list of the medicines your child takes. Ask your doctor when you can expect to have your child's test results.

Where can you learn more?

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