106   Functional Network Analysis in Surgical XXXX @entity1 Using Magnetoencephalography.

@entity1 @entity410 @entity1625 @entity132 @entity1315 @entity302 @entity74
INTRODUCTION: Intractable @entity1625 is a @entity74 with profound effects on cognition and quality of life. @entity302 surgery can lead to @entity410 freedom in @entity1 with @entity1625 ; however, sometimes it fails owing to an incomplete delineation of the epileptogenic zone (EZ). Brain networks in @entity302 can be studied with resting-state functional connectivity (RSFC) analysis, yet previous investigations using functional MRI or electrocorticography have produced inconsistent results. Magnetoencephalography (MEG) allows noninvasive whole-brain recordings, and can be used to study both @entity132 in @entity1625 and regional connectivity at the EZ. METHODS: In MEG recordings from presurgical @entity302 @entity1 , we examined: (1) global functional connectivity maps in @entity1 vs controls, and (2) regional functional connectivity maps at the region of resection, compared with the homotopic nonepileptogenic region in the contralateral hemisphere. RESULTS: Sixty-one @entity1 were studied, including 30 with mesial @entity1315 and 31 with focal neocortical @entity302 . Compared with a group of 31 controls, @entity302 @entity1 had decreased RSFC in widespread regions, including perisylvian, posterior temporoparietal, and orbitofrontal cortices (P < .01, false discovery rate-corrected). Decreased mean global connectivity was related to longer duration of @entity302 and higher frequency of consciousness-impairing @entity410 (P < .01, linear regression). Furthermore, @entity1 with increased regional connectivity within the resection site (n = 24) were more likely to achieve postoperative @entity410 freedom (87.5% with Engel I outcome) than those with neutral (n = 15, 64.3% @entity410 free) or decreased (n = 23, 47.8% @entity410 free) regional connectivity (P < .02,   ). CONCLUSION: Widespread global decreases in functional connectivity are observed in @entity1 with @entity1625 and may reflect deleterious long-term effects of recurrent @entity410 . Furthermore, enhanced regional functional connectivity at the area of resection may help predict @entity410 outcome and aid surgical planning.
