Electroencephalogram (EEG)

What is an electroencephalogram?

An electroencephalogram records the electrical activity generated in the brain. An EEG is done by applying electrodes directly onto the scalp surface. An EEG provides an assessment of cerebral activity, which is useful in the diagnosis of epilepsy, and as a screening procedure for coma and organic brain syndrome.

What can I expect before the test?

Take only the medications approved by the doctor who ordered the EEG.

You may eat your regular meals, but do not drink coffee, tea, or cola drinks in the 24 hours before the test.

Shampoo your hair the night before the test. Do not put on hair spray or hair products such as gels or mousse. Do not have your hair elaborately done before your test.

You may be asked to be "sleep-deprived." This means that you must be awake from the day before.

Your physician will give you instructions about this.

How long does the test take?

It will take approximately 45-60 minutes.

Please allow an extra 10-15 minutes prior to the test for registration.

What can I expect during the test?

YOU WILL NOT RECEIVE AN ELECTRICAL SHOCK.

Electrodes will be arranged on your scalp to permit the recording of activity in various head regions; the amplified activity of the working cells (neurons) will be recorded continuously by the monitor.

For baseline recording, you will lie quietly with your eyes closed.

For activation procedure (done to elicit abnormal electrical stimulation) you will be asked to hyperventilate for 3-4 minutes and there will be a bright flashing light; eyes are closed for both activations.

You may be asked to fall asleep so that the machine can obtain any abnormal brain waves during sleep and upon awakening.

What can I expect after the test?

The electrodes will be removed from your head.

You will be given a comb to straighten out your hair.

You will be allowed to leave and return to your normal routine.

Your test will be interpreted by a neurologist later that day.

A report of the test will be forwarded to your physician, who will discuss the results with you at a later date.