MEG Slow Wave Dipole Density (SWDD) in Presurgical Evaluation of Epilepsy Patients: Preliminary Results of a Prospective Study

Abstract

Main objective(s)The aim of this prospective study is to examine the potential contribution of SWDD localisation in clinical preoperative epilepsy focus localisation.MethodsPreoperative MEG-SWDD localisations are calculated and overlaid on MR-images of pharmaco-resistant epilepsy patients undergoing presurgical focus localisation evaluation. For all 10 patients who have been operated within at least 6 months, postsurgical outcomes available up to now, are discussed. SWDD localisation results are compared to other preoperative findings and to MEG-spike results and are correlated to postoperative outcome (Engel) after 6 months or 12 months.Results7 of 10 patients showed significant local increase of SWDD. In these SWDD localisation results were always concordant with preoperative findings. All 7 patients were postoperatively seizure-free or had a worthwhile improvement of seizure situation. 3 of 10 patients showed no significant local increase of SWDD and, therefore, were without SWDD result.Comparison to MEG spike results: Among these 7 patients, 6 showed MEG-spike concordant localisations, one had no spikes in the MEG.ConclusionsSWDD is able to localise brain areas exhibiting pathological slow wave activity and might become a useful tool for preoperative epilepsy diagnosis.