Epilepsy Services: Electroencephalogram (EEG)

UW Health's comprehensive epilepsy program offers state-of-the-art care for patients with epilepsy or those suspected of having seizures, including using electroencephalogram (EEG) to monitor the activity of the brain.


Electroencephalogram (EEG) and Epilepsy


An EEG records the electrical activity of the brain. Highly-sensitive monitoring equipment records the activity through electrodes that are placed on the patient’s scalp.
Through this painless test, physicians are able to diagnose a variety of neurological problems, from common headaches and dizziness to seizure disorders, strokes and degenerative brain disease.
Types of EEG

Invasive Monitoring EEG


Invasive monitoring EEG uses subdural and depth electrodes to record electrical activity directly from the brain and clarify any inconsistencies presented by less invasive EEG results. Invasive EEG can present an accurate gauge of important language and movement functions.

  • Subdural electrodes are implanted surgically as a strip or grid, and record brain information without interference of the brain and scalp. Mild electric currents then stimulate parts of the brain, activating them or shutting them down. This mapping procedure is almost always painless, though the initial implantation of electrodes can cause discomfort that can be treated with pain medication.
  • Depth electrodes are placed directly on the brain but, unlike subdural electrodes, do not require a large opening in the skull. After placement, computed tomography (CT) scans ensure proper positioning and reveal any bleeding in the brain. Depth electrodes provide the best recordings of seizures deep in the brain.