An electroencephalogram (EEG) is one of the main tests used to diagnose epilepsy. There are several types of EEGs that may be performed.
A routine EEG is a test that uses small flat metal disks called electrodes that are attached to your scalp. The electrodes detect the electrical activity in your brain. You will experience little or no pain or discomfort during the EEG. A routine EEG typically takes 30 minutes to an hour to complete and is done during a scheduled appointment with your doctor.
It can sometimes be difficult to detect a seizure episode during a routine EEG. Therefore a doctor may recommend an ambulatory EEG, also called an extended EEG. An ambulatory EEG typically studies the brain for 24, 48, or 72 hours. For an ambulatory EEG, you do not have to be admitted to the hospital. You will wear a portable EEG unit, which will monitor your brain’s activity throughout the day, increasing the chances of catching an epileptic event.
A video EEG records your brain activity and takes a video of your brain at the same time. This is an important early step in the management of seizures because people may have seizures for reasons other than epilepsy, such as irregular heart rhythm or stress. The video EEG is a helpful tool for patients whose seizures do not respond to anti-seizure medications because it helps identify what part of the brain is causing the seizures. Knowing where the seizures are coming from can help patients and doctors make decisions about whether surgery is a good option to treat epilepsy.