Test: EEG

Electroencephalography (EEG) may be used to help diagnose conditions, such as epilepsy, that are associated with abnormal electrical activity in the brain. Electrodes are attached to a person’s scalp, and recordings are made of brain activity with the eyes open and closed. A strobe light may be switched on for short periods to see if brain activity changes. The procedure takes approximately 20–30 minutes and is painless.

During the procedure

With the electrodes attached to your scalp, you relax on a bed while a continuous recording of your brain activity is made.



These three EEG traces taken from a multitrace recording show an episode of abnormal electrical activity in the brain of a person who has had recurrent seizures.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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