An electroencephalogram (EEG) is a test that records electrical activity in the brain. Brain cells communicate via electrical impulses and are active all the time, even during sleep. This activity shows up as wavy lines on an EEG recording.
An EEG is one of the main diagnostic tests for epilepsy (seizures). An EEG can also play a role in diagnosing other brain disorders.
During the test, patient will usually lie comfortably on the exam bed for about 20-30 minutes with eyes closed. Initially small electrodes are attached the scalp using special adhesive and removed after the test. The electrodes do not transmit any sensations but just record the brain activity.
There is specific risk involved with the EEG. It is safe and painless. Sometimes seizures are intentionally triggered in people with epilepsy during the test, but appropriate medical care is provided if needed.
The patient should wash their hair the night before or the day of the test, but should not apply conditioners, or apply hair creams, sprays or styling gels.
If sleep deprived EEG is ordered, you might be asked to sleep less or avoid sleep the night before your test.