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An electroencephalogram (EEG) is a diagnostic test doctors use to record and analyze brain waves. During an EEG scan, you can typically expect to relax comfortably, as the test is painless. In fact, the most troubling part of it may be lying still if you have a tendency to become restless. In some cases, you may receive a sedative before an EEG scan, but this is usually only to help you fall asleep if your scan is to take place while you are sleeping. Usually, an EEG scan lasts for about a half hour to 60 minutes.
When you have to undergo an EEG scan, you will likely be asked to relax in a position that is comfortable for you. For example, you may be asked to relax in a comfortable chair. Typically, an EEG technician will attach electrodes to your scalp using adhesive. The adhesive is unlikely to cause damage to your scalp or hair. You can usually wash it out once you return home after the test.
The electrodes used for an EEG are flat metal disks that connect to a device used to transmit brain waves to a computer. The brain waves are enlarged and recorded on the computer for your doctor’s analysis. The test only analyzes your brain wave patterns. It cannot reveal your thoughts to the test taker or the doctor who analyzes your brain waves.
You are likely to spend most of an EEG scan with your eyes closed. The EEG technician may make several requests during the course of the test, however. For example, he may ask you to open and close your eyes or gaze at a photograph. He may also ask you to read, solve a simple math problem, or stare at a light. He may even ask you to breathe deeply in an effort to detect changes in your brain’s electrical activity.
If you are scheduled to have an EEG scan performed while you are asleep, you will likely receive a sedative to help you sleep during the test. As with a regular EEG scan, this test is intended to record and evaluate brain activity, which may appear different when you are asleep. You may, however, have to remain at the testing facility for a short time after an EEG scan that is performed while you are sleeping. This will allow the sedative to wear off fully. You will likely need to have a friend or family member drive you home after the test, though this is usually not necessary if you do not receive a sedative.