What is an EEG?
An electroencephalogram (EEG) is a neurodiagnostic test that measures and records the electrical activity in your brain.
Why is an EEG performed?
EEGs are used to identify abnormalities in your brain, such as a tumor or the presence of a stroke. Certain conditions, such as seizures, can be seen by studying the changes and patterns in your brain’s electrical activity. EEGs are often used to diagnose epilepsy, a group of related conditions characterized by their tendency for recurrent seizures.
What to expect:
You will be instructed about what to wear to your appointment, what to eat before the test, how the test will be performed, and how the test will feel.
Before your EEG, your doctor may ask you to stop taking certain medications that could affect your brain’s normal electrical activity. The night before or the morning of your EEG, shampoo your hair, rinse with clear water, and do not apply conditioner or styling products after shampooing.
When you arrive for your EEG, you will lie on your back on a bed or table or you will be seated in a chair. Special sensors called electrodes will be attached to your scalp using a special paste. The electrodes are hooked by wires to a computer that will record the electrical activity in your brain. The computer will record your brain’s electrical activity by drawing a series of wavy lines on a moving piece of paper or as an image on the computer screen.
An EEG is painless and usually takes 1 – 2 hours to complete. Though your brain’s electrical activity is recorded, no electrical current is ever put into your body. The EEG results are often available the same day or day after.