What is stereoelectroencephalography (SEEG)?

Stereoelectroencephalography (SEEG) is a minimally invasive surgical procedure that is used to identify areas of the brain where epileptic seizures originate. During SEEG, doctors place electrodes in targeted brain areas, which are then monitored to precisely locate the source of the seizure. A SEEG can find seizure sites deep in the brain that a regular electroencephalography (EEG) test may not reach. It covers both sides (hemispheres) of the brain.

When the source of the seizure is found, another brain surgery can be planned to help get seizures under control. This second surgery is usually done four to eight weeks after the SEEG. The ultimate goal of this surgery is to make the patient seizure-free, even with triggers.

Who is a candidate for a SEEG?

If you have generalized epilepsy, SEEG surgery is not an option. SEEG may help if you:

  • Have focal epilepsy and seizures (complex partial seizures) that do not respond to two anti-convulsant medications or medical treatment.
  • Are a potential candidate for epilepsy surgery.
  • If the origin sites of your seizures can’t be found with other tests.

What are the benefits of SEEG?

  • SEEG is a minimally invasive approach for epilepsy localization. To implant the electrodes, the surgeon makes 10 to 20 (depending on the patient) small incisions in the scalp and skull, with minimal blood loss.
  • While SEEG surgery lasts about four hours and requires general anesthesia, removal of the electrodes is a simple procedure that only takes 10 to 15 minutes under local anesthesia.
  • SEEG reaches areas deep in the brain.
  • SEEG can be used to monitor both sides of the brain.

What are the risks of a SEEG?

Though SEEG is safe and less invasive it is still brain surgery, which has risks. The main risks are:

  • Infection.
  • Bleeding.
  • Stroke.

Last reviewed by a Cleveland Clinic medical professional on 01/08/2020.


  • Iida K, Otsubo H. Stereoelectroencephalography: Indication and Efficacy. Neurol Med Chir (Tokyo). 2017;57(8):375–385. doi:10.2176/nmc.ra.2017-0008
  • Childhood Epilepsy Surgery Foundation. Stereotactic EEG. Accessed 1/15/2020.
  • Epilepsy Foundation. Implanted EEG Electrodes. Accessed 1/15/2020.

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