Electroencephalogram (EEG)

Electroencephalogram (EEG)

An electroencephalogram (EEG) is a test used to measure and record the electrical activity of your brain. With special sensors attached to your head, a computer records your brain’s electrical activity. Changes from a normal pattern of electrical activity can indicate certain conditions, such as:

  • Epilepsy, including type of seizure occurring
  • Sleep disorders, such as narcolepsy
  • Dementia
  • Brain damage

Our approach

At Northwell Health Neuroscience Institute, we provide you with the most advanced technology for measuring and recording the electrical activity of your brain. This includes multiple types of electroencephalogram tests, including:

  • Routine EEGs
  • Sleep deprived EEGs
  • Ambulatory EEG monitoring
  • Intracranial EEGs
  • Inpatient video EEG monitoring during medication changes, refractory epilepsy or for initial diagnosis and classification of epilepsy


EEG Risks and side effects

Electroencephalogram is a safe and painless test. Some of the adhesive used to hold electrodes to your head may stick in your hair and can be easily washed out. If needle electrodes were used, you may have some soreness or bleeding for one to two days after the test.  Although rare, you may experience some skin irritation or even ulceration.

Preparing for treatment

If you require an EEG, it may be performed either in a hospital or in your doctor’s office. An EEG technologist will perform the test. During the test, you will be asked to sit in a chair with your eyes closed or to lie on your back on a table or bed. The technologist will use electrodes that are hooked by wires to a computer that record the electrical activity in your brain. 

What to expect after treatment

An EEG test can take one to two hours. You can return to normal activities immediately after the test. However, if you were given a sleep medication, you will need someone to drive you home following the test. Your doctor will follow up with you regarding the results of your EEG test.