Ambulatory Electroencephalography (EEG)

What is an ambulatory EEG?

An ambulatory electroencephalogram (EEG) is a neurodiagnostic test that measures and records the electrical activity in your brain. Unlike an EEG, an ambulatory EEG allows an extended recording in a patient’s home. The patient can move around and is not required to stay in the hospital for the recording.

Why is an ambulatory EEG performed?

An ambulatory EEG is often performed when an extended recording is necessary to diagnose a disorder. While a traditional EEG records for 1 – 2 hours, an ambulatory EEG can record continuously for up to 72 hours, increasing the likelihood that abnormal electrical activity in the brain can be recorded.
Your doctor may order an ambulatory EEG for you to confirm an epilepsy diagnosis, confirm the existence of seizures you may not be aware of, evaluate the effectiveness of a treatment plan for a seizure disorder, evaluate nocturnal or sleep-related events, or evaluate syncope, a sudden and temporary loss of consciousness.

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 ambulatory 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 ambulatory EEG, shampoo your hair, rinse with clear water, and do not apply conditioner or styling products after shampooing.

During your ambulatory EEG appointment, 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 small, portable recording unit that will record the electrical activity in your brain. The portable recording unit will record your brain’s electrical activity by drawing a series of wavy lines as an image on the computer screen.

To help your doctor understand what occurred during the testing period, you may be asked to write down all the things you did during the recording in a notebook. You may be asked to record activities such as eating, speaking, watching TV, etc. You should not bathe while undergoing an ambulatory EEG.

An ambulatory EEG is painless and your recording may take a full day or more to complete. When testing is over, you will have the electrodes removed and along with the portable recording unit.

Though your brain’s electrical activity is recorded, no electrical current is ever put into your body. The EEG results are often available within a week.