title: MEG in frontal lobe epilepsies: localization and postoperative outcome.
abstract: OBJECTIVE
  This study aimed to analyze magnetoencephalography (MEG) localizations of epileptic clusters in different cortical regions of the frontal lobe and relate these findings to postoperative outcomes associated with frontal lobe epilepsy (FLE).
  
  
  METHODS
  Thirty-nine patients from the Epilepsy Center of Erlangen-Nuremberg University with or without lesions on their magnetic resonance imaging (MRI) scans underwent MEG measurements and operation and were then analyzed retrospectively. MEG data were obtained using systems with either 74 or 248 channels. Single dipole analysis assuming a spherical head model was performed for localization.
  
  
  RESULTS
  Epileptic clusters were detected by MEG in 30 patients, corresponding to a sensitivity of 76.9%; there was a sensitivity of 66.7% (20 of 30) in patients with monofocal activity (70% had an Engel class 1 outcome) and 33.3% (10 of 30) in patients with multifocal activity (20% had an Engel class 1 outcome). Of the patients who had isolated clusters, the distance between the MEG localizations and the respective lesions was equal to or <3 cm in 90% (18 of 20) of patients (13 of them had an Engel class 1 outcome) and >3 cm in 10% (2 of 20) of patients (one of them had an Engel class 1 outcome). A statistical difference was found between the outcomes of patients with a single focus and with multiple foci (p < 0.05).
  
  
  CONCLUSIONS
  Patients with a single focus had better postoperative outcomes compared with patients with multiple foci. MEG localizations close to the lesion marked the lesion or its surrounding network as epileptogenic. Therefore, source localization can provide important information for the presurgical evaluation of patients with FLE.
authors.affiliation: Neurological Clinic, University Hospital Erlangen, Erlangen, Germany. hermann.stefan@uk-erlangen.de
authors.forename: Hermann
authors.initials: H
authors.lastname: Stefan
authors.forename: Xintong
authors.initials: X
authors.lastname: Wu
authors.forename: Michael
authors.initials: M
authors.lastname: Buchfelder
authors.forename: Stefan
authors.initials: S
authors.lastname: Rampp
authors.forename: Burkhard
authors.initials: B
authors.lastname: Kasper
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hopfengärtner
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Schmitt
authors.forename: Arnd
authors.initials: A
authors.lastname: Dörfler
authors.forename: Ingmar
authors.initials: I
authors.lastname: Blümcke
authors.forename: Dong
authors.initials: D
authors.lastname: Zhou
authors.forename: Daniel
authors.initials: D
authors.lastname: Weigel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis* / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015225:Magnetoencephalography; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011300:Preoperative Care; D016896:Treatment Outcome; D055815:Young Adult