title: Epileptic focus localization based on resting state interictal MEG recordings is feasible irrespective of the presence or absence of spikes.
abstract: OBJECTIVE
  To investigate whether epileptogenic focus localization is possible based on resting state connectivity analysis of magnetoencephalographic (MEG) data.
  
  
  METHODS
  A multivariate autoregressive (MVAR) model was constructed using the sensor space data and was projected to the source space using lead field and inverse matrix. The generalized partial directed coherence was estimated from the MVAR model in the source space. The dipole with the maximum information inflow was hypothesized to be within the epileptogenic focus.
  
  
  RESULTS
  Applying the focus localization algorithm (FLA) to the interictal MEG recordings from five patients with neocortical epilepsy, who underwent presurgical evaluation for the identification of epileptogenic focus, we were able to correctly localize the focus, on the basis of maximum interictal information inflow in the presence or absence of interictal epileptic spikes in the data, with three out of five patients undergoing resective surgery and being seizure free since.
  
  
  CONCLUSIONS
  Our preliminary results suggest that accurate localization of the epileptogenic focus may be accomplished using noninvasive spontaneous "resting-state" recordings of relatively brief duration and without the need to capture definite interictal and/or ictal abnormalities.
  
  
  CONCLUSIONS
  Epileptogenic focus localization is possible through connectivity analysis of resting state MEG data irrespective of the presence/absence of spikes.
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA.
authors.forename: B
authors.initials: B
authors.lastname: Krishnan
authors.affiliation: Biomedical Engineering, Louisiana Tech University, LA, USA.
authors.forename: I
authors.initials: I
authors.lastname: Vlachos
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA.
authors.forename: Z I
authors.initials: ZI
authors.lastname: Wang
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA.
authors.forename: J
authors.initials: J
authors.lastname: Mosher
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA.
authors.forename: I
authors.initials: I
authors.lastname: Najm
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA.
authors.forename: R
authors.initials: R
authors.lastname: Burgess
authors.affiliation: Biomedical Engineering, Louisiana Tech University, LA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Iasemidis
authors.affiliation: Cleveland Clinic Epilepsy Center, Cleveland, OH, USA. Electronic address: alexopa@ccf.org.
authors.forename: A V
authors.initials: AV
authors.lastname: Alexopoulos
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004569:Electroencephalography / Q000379:methods*; D004828:Epilepsies, Partial / Q000175:diagnosis / Q000503:physiopathology*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D015225:Magnetoencephalography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012146:Rest / Q000502:physiology
keywords: Epilepsy; Epileptogenic focus localization; Information flow; Interictal period; MEG; Resting state connectivity