Electroencephalogram (EEG) | Brain Activity Test | MedStar Health

The electroencephalogram (EEG) is a commonly used diagnostic test that measures and records the electrical activity in the brain.

An EEG can be used to:

  • Diagnose epilepsy and seizures
  • Study sleep disorders

  • Evaluate problems in brain functioning, such as confusion, dementia, or loss of consciousness
  • Evaluate psychiatric patients

The procedure typically takes one hour and is painless. To perform the test, a nurse or technician will attach 16-25 electrodes to your scalp, using a special, temporary glue. You will not feel any pain as the electrical activity in your brain is recorded.

During the exam, the nurse or technician may ask you to breathe slowly or quickly, or may use visual stimuli to evaluate their effects on your brain activity. Once the exam is completed, you are able to go home and resume normal activities. Patients who have been sleep deprived for the study should make arrangements to get a ride home and not drive.

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