EEG (ELECTROENCEPHALOGRAM)

EEG is short for electroencephalogram. This painless test records the brain's electrical activity. Nerve cells work by carrying tiny electrical charges. Several electrodes are attached to the person's head. They measure low-level electricity, but cannot shock the patient.

An EEG can help evaluate or diagnose:

seizure disorders, such as epilepsy
head injury
psychological disorders and
brain death in terminally ill patients

Prior to the test, the person must avoid caffeine. It is also necessary to stop taking drugs that affect the nervous system for 1 or 2 days. The test lasts about 30 to 60 minutes. The person relaxes in a reclining chair or on a bed. It is important to relax, because nervousness can change brain wave patterns.

A technician attaches 16 or more electrodes to the scalp with a special paste. The electrodes send information to a machine that records brain waves on paper. During the test, the examiner may ask the person to remain still, open or close his eyes, or breathe deeply and rapidly. Certain disorders require an EEG during sleep. The device records how the brain responds to these changes. The brain wave recordings are available immediately for interpretation.

After the test the person can resume taking prescription drugs.

Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.

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