Electroencephalography (EEG) is a test that measures your brain wave activity (brain function). Your doctor may order this test to check for seizures or other brain problems. For this test, small metal disks (electrodes) are attached to the scalp with glue, or with water-based gel or paste. During the test, wavy lines (waveforms) appear on a screen or on paper. They will be studied to assess your brain function. In some people who are prone to seizures, parts of this test may slightly increase their chance of having a seizure but the benefits of this test far outweigh this risk.
Prepare for your test as instructed. Wash and dry your hair. But don't use any hairstyling products. Your scalp and hair should be clean and free of excess oil. Take your routine medications, unless told not to. You may be asked to sleep during the EEG. To help you do this you may be told to stay up all or part of the night before the test or you may be given medication to help you sleep during your test. If so, someone will need to drive you home after the test. Your test will take approximately 90 minutes. Please allow extra time to check in.
For your safety and the success of your test, tell the technologist:
You may also be asked questions about your overall health.
You will sit in a reclining chair or lie down on an exam table in a softly lighted room. The technologist will measure certain points on your head. He or she will use a special pencil to mark the spots where electrodes will be placed on your scalp. Your scalp will be rubbed with a mild abrasive, and electrodes will be attached. You will then be asked to do any of the following:
When your test is done, all of the electrodes will be removed. At home, wash your hair to remove any remaining glue, gel or paste. You can get right back to your normal routine. If you stopped taking any medications before the test, ask your doctor when you can start taking them again. Your doctor will let you know when your results are ready.