Ambulatory electroencephalogram (EEG)

An electroencephalogram (EEG) measures and records the electrical activity in your brain. Your physician may recommend an ambulatory EEG test to get a recording over a few days, as opposed to a few hours. You're not required to stay in the hospital for an ambulatory EEG. You can move around, typically at home.

Why would your doctor recommend an ambulatory EEG?

Your brain's electrical activity changes frequently, and routine EEGs only measure activity over a few minutes. Your HonorHealth neurologist might suggest an ambulatory EEG to evaluate your brain waves over a few days. This lets your physician to see your brain waves while you're awake and while you're asleep.

Your physician might recommend an ambulatory EEG to diagnose or study Epilepsy or nonepileptic seizures.

It's helpful to study you while you're engaged in your normal day-to-day activities because those events sometimes might serve as triggers for your symptoms.

How to prepare for an ambulatory EEG

You should arrive for your appointment with clean and dry hair, without any oils or heavy products.

  1. Wear comfortable clothing. The set-up is a bit involved, and you might want to consider a button-down shirt and/or a tank top to make things easier once your electrodes are hooked up.
  2. Plan on eating and sleeping as you normally would — before, during and after the testing.
  3. Take your prescribed medication(s) as usual, unless your physician instructs you otherwise.

What can you expect during an ambulatory EEG?

When you arrive at the office, you may first be asked a few questions about your symptoms. This information is helpful in interpreting the test and providing you with a diagnosis.

You'll then lie down on a table where you'll be made to feel warm and comfortable. A technician will measure and mark your head with a grease pencil to ensure the electrodes are put on the proper place. Electrodes connected to EEG wires will be placed on your scalp using a gritty gel followed by a type of paste to affix them. Everything will be covered with gauze and a special cap to ensure the electrodes stay in place.

Some of the testing will take place in the office. You'll be asked to lie quietly, open and close your eyes, answer simple questions and perhaps perform a few mental tasks (such as simple math or spelling). You also may be asked to do a bit of deep breathing, which could make you feel lightheaded or dizzy. This is a normal reaction and will subside once you stop the deep breathing exercises.

You'll then be sent home for 24 to 72 hours. During this time, you'll be attached to a portable monitor. You'll be asked to keep a diary with notes about what you're doing and whether you're experiencing seizures or other symptoms.

Once the test is over, you'll receive instructions on what to do next. You may remove the electrodes at home or have them removed in the office. It takes a bit of work to remove the paste. Once you're back home you'll want to wash your hair to get all the sticky residue out of your hair.

Although the testing is inconvenient, it's non-invasive and not painful.