title: Gradient magnetic-field topography reflecting cortical activities of neocortical epilepsy spikes.
abstract: OBJECTIVE
  To compare and validate the gradient magnetic-field topography (GMFT) method of current source localization for understanding epileptic zones against equivalent current dipole (ECD) and intracranial video-EEG (IVEEG) data in patients with intractable neocortical epilepsy.
  
  
  METHODS
  We used retrospective data from eight patients to determine GMFT at onset (O) and peak (P) of interictal magnetoencephalography (MEG) spikes and mapped GMFT(O) and GMFT(P) locations and distributions using 12 zones in unilateral hemisphere. We compared GMFT with ECD, ictal onset zones (IOZ) and interictal zones on IVEEG, and seizure outcomes.
  
  
  RESULTS
  We projected GMFT(Os) and (Ps) for all spikes on volume-rendered brain surfaces. We localized ECDs for 6-61% of spikes (mean, 28.4%). GMFT(Ps) (mean, 10.3 zones) extended over more zones than GMFT(Os) (6.3 zones) for each spike (p<0.01). The ECD distributions (2.3 zones) were almost equal to the zones of IOZ and surgical areas. GMFT(O) localizations distributed much more extensively than IOZs and surgical areas in three patients with residual seizures comparing with those in five seizure-free patiens.
  
  
  CONCLUSIONS
  We validate the potential of GMFT to study the distribution of MEG spikes. GMFT has an advantage in analyzing the cortical activity and propagation from MEG spikes in neocortical epilepsy.
authors.affiliation: Department of Neurosurgery, Hiroshima University, Hiroshima, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Shirozu
authors.forename: Koji
authors.initials: K
authors.lastname: Iida
authors.forename: Akira
authors.initials: A
authors.lastname: Hashizume
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Hanaya
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kiura
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kurisu
authors.forename: Kazunori
authors.initials: K
authors.lastname: Arita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
mesh_terms: D000293:Adolescent; D000328:Adult; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004569:Electroencephalography / Q000379:methods; D004827:Epilepsy / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D015225:Magnetoencephalography; D008297:Male; D009493:Neurosurgery / Q000379:methods; D012189:Retrospective Studies; D016896:Treatment Outcome; D014741:Video Recording / Q000379:methods; D055815:Young Adult