The Scalp EEG is the Most Useful Test in Extratemporal Lobe Epilepsy Surgery

In the June 3 online publication of the journal JAMA Neurology, Dr. Noe and colleagues from the Mayo Clinic in Minnesota and Arizona present an analysis of the noninvasive diagnostic test results of 85 patients who have drug resistant, nonlesional (no abnormalities on MRI) extratemporal lobe epilepsy to assess which tests are the most predictive of a good surgical outcome. The study found:

• 38% of 24 patients who underwent surgery with a nonlesional extratemporal lobe epilepsy focus had an excellent outcome after resective epilepsy surgery for up to 10 years.

• The most consistent predictor of success was localized interictal epileptiform discharge on scalp EEGs.

• The authors concluded that scalp EEG is the most useful test for identifying patients with normal MRI findings and extratemporal lobe epilepsy who were likely to have excellent outcomes after surgery.

• Extending outcome analysis beyond the resective surgical group to the entire group of patients highlights the challenge that these patients pose.

  • Of 31 patients undergoing intracranial EEG, 9 ultimately went on to resective surgery and only 11% had long term excellent outcomes.