Electroencephalogram (EEG, or “Brain Wave Test”)

An electroencephalogram is a test to detect problems in the electrical activity of the brain. Brain cells communicate with each other by producing tiny electrical impulses. In an EEG, this faint electrical activity is measured by putting electrodes on the scalp.

The test is performed by an EEG technician in your healthcare provider's office, at a hospital or at an independent laboratory. You will be asked to lie on your back on a bed or in a reclining chair. The technician will apply between 16 and 25 flat metal disks (electrodes) in different positions on your scalp, held in place with a sticky paste. The electrodes are connected by wires to an amplifier and a recording machine.

The recording machine converts the electrical impulses into patterns that can be seen on a computer screen as well as stored on a computer disk (Before computers, the activity was printed on paper).

In either case, the electical activity looks like a series of wavy lines. You will need to lie still with your eyes closed because any movement can alter the results. You may be asked to do certain things during the recording, such as breathe deeply and rapidly for several minutes or look at a bright flashing light.

• Multiple Sclerosis
• Parkinson’s Disease
• Migraine Headaches
• Balance and dizziness disorders
• Post-Concussion Syndrome

How to Prepare for the Test

• You will need to wash your hair the night before the test. Do not use any oils, sprays, or conditioner on your hair before this test.
• Your healthcare provider may want you to stop taking certain medications before the test. Do not change or stop medications without first talking to your healthcare provider.
• You should avoid all foods containing caffeine for eight hours before the test.
• You may be asked to reduce your sleep time the night before, since sometimes it’s necessary to sleep during the test. If you're asked to sleep as little as possible before the test, don't consume any caffeine, energy drinks, or other products that help you stay awake.

How the Test Will Feel

This test causes no discomfort. Although having electrodes pasted onto your skin may feel strange, they only record activity and do not produce any sensation. No significant electricity passes from the electrode into your skin.

Why the Test is Performed

EEG is used to help diagnose if you're having seizures and if so, what type. An EEG is also used to find the causes of confusion, and to evaluate head injuries, tumors, infections, degenerative diseases such as Alzheimer's disease, and abnormal changes in body chemistry that affect the brain.

It is also used to:

• Evaluate problems with sleep (sleep disorders).
• To investigate periods of unconsciousness.
• To monitor the brain during brain surgery.

EEG cannot be used to measure intelligence.

Risks

The procedure is very safe. However, the flashing lights or fast breathing (hyperventilation) required during the test may trigger seizures in those with seizure disorders. The healthcare provider performing the EEG is trained to take care of you if this happens. It may be difficult to get the paste out of your hair, but it should come out after a few washings with regular shampoo.