What is an EEG?

One of the tests that is frequently performed in the diagnosis and treatment of epilepsy is an EEG. In this test, electrodes are attached to the scalp and the electrical activity of the brain measured. Abnormalities in the pattern that is obtained can indicate whether there is a behavior of the brain that causes seizures.

It is quite painless and normally takes about 40 minutes. We like to obtain patterns during sleep, drowsiness and while the patient is awake.

We will also do tests over several days (ambulatory EEG). In these tests, the patient wears a small recording device that records brain electrical activity during normal activites and thus gives the doctor a much more comprehensive picture.

It is probable that an EEG will be obtained during a 3-5 day hospital visit (Video EEG). This is different from the above tests - in this case, we want the patient to have a seizure so that we can see the changes on an EEG and correlate this with a video recording of what the patient is doing at the time. As we hope for a seizure, we stop medications. The test is performed in a hospital so that the patient is safe.

The Video EEG is a very important test that differentiates between different types of seizure - the results may make a big difference in the treatments that will be used to get seizures controlled.