Tests and diagnostics
What happens during an EEG
Demo Author
An electroencephalogram, or EEG, records the electrical activity of the brain. If a neurologist has asked you to have one, here is what to expect.
Information
This article is general information and does not replace advice about your own situation. Reviewed by Dr. Priya Raman, MBBS, MD, DM (Neurology).
Before the test
Wash your hair the night before and do not use oil, gel, or spray, so the sensors stick well. Ask the clinic whether to keep taking your usual medicines. For some EEGs you may be asked to sleep less the night before.
During the test
A technologist attaches small sensors to your scalp with a paste. You then rest with your eyes open or closed. You may be asked to breathe deeply for a few minutes or to look at a flashing light. A standard recording usually takes about 30 to 60 minutes. The test does not send electricity into the body.
After the test
The sensors and paste are removed. You can wash your hair and return to your usual activities. There is no recovery time for a standard EEG.
Getting your results
A neurologist reviews the recording and explains what it means at a follow-up, together with your history and any other tests. An EEG on its own is not a diagnosis.
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