Why And When?

An electroencephalogram (EEG) is a test used to detect abnormalities related to electrical activity of the brain. This procedure tracks and records brain wave patterns. Small metal discs with thin wires (electrodes) are placed on the scalp, and then send signals to a computer to record the results.

Why Is EEG Testing Done?

EEG testing is done to diagnose epilepsy and see what type of seizures are occurring. EEG is the most useful and important test for confirming a diagnosis of epilepsy. Ability to check for problems with loss of consciousness or dementia. It can help determine a person's chance of recovery after a change in consciousness. Contributes to study sleep disorders, such as narcolepsy.
Watch brain activity while a person is receiving general anesthesia during brain surgery.
Help find out if a person has a physical problem (problems in the brain, spinal cord, or nervous system) or a mental health problem.

Preparation

Before the day of the electroencephalogram (EEG) test, tell your doctor if you are taking any medicines. Your doctor may ask you to stop taking certain medicines (such as sedatives and tranquilizers, muscle relaxants, sleeping aids, or medicines used to treat seizures) before the test. These medicines can affect your brain's usual electrical activity and cause abnormal test results.

Do not eat or drink foods that have caffeine (such as coffee, tea, cola, and chocolate) for 12 hours before the test.