Electroencephalography (EEG) Introduction
The electroencephalogram (EEG) is a measure of brain waves. It is a readily available test that provides evidence of how the brain functions over time.
- The EEG is used in the evaluation of brain disorders. Most commonly it is used to show the type and location of the activity in the brain during a seizure. It also is used to evaluate people who are having problems associated with brain function. These problems might include confusion, coma, tumors, long-term difficulties with thinking or memory, or weakening of specific parts of the body (such as weakness associated with a stroke).
An EEG is also used to determine brain death. It may be used to prove that someone on life-support equipment has no chance of recovery.
Scientists first captured and recorded brain waves in dogs in 1912. By the 1950s the EEG was used commonly throughout the United States.
Very few risks are associated with an EEG. The patient may be asked not to take certain seizure or antidepressant medications 1 to 2 days before having an EEG. This may make the person more prone to having a seizure, which is exactly what the doctor would like to measure. During an EEG, the doctor may encourage the things that stimulate seizures, such as deep breathing or flashing lights, so that he or she can see what happens in the brain during the seizures.
Medically Reviewed by a Doctor on 4/5/2016
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