Diagnostic tests
Electroencephalogram (EEG)
An electroencephalogram records the brain’s electrical activity through small sensors placed on the scalp.
What it is
An electroencephalogram records the brain’s electrical activity through small sensors placed on the scalp. It helps evaluate seizures, epilepsy and episodes of altered awareness. A routine EEG is done in the office; an ambulatory EEG records for one or more days at home.
How to prepare
Wash your hair the night before and skip conditioners, oils and sprays. Take your usual medications unless your physician says otherwise. You may be asked to limit sleep the night before.
What to expect
Sensors are attached with a removable paste. You rest quietly and may be asked to breathe deeply or look at a flashing light. The test is painless; a routine EEG typically takes about an hour.
This information is educational and does not replace a medical evaluation.