title: Magnetoencephalographic studies of focal epileptic activity in three patients with epilepsy suggestive of Lennox-Gastaut syndrome.
abstract: OBJECTIVE
  To determine the electromagnetic sources of localized epileptic activities using magnetoencephalography (MEG) in three adult patients with epilepsy suggestive of Lennox-Gastaut syndrome (LGS).
  
  
  METHODS
  MEG and simultaneous electroencephalography (EEG) were recorded from three adult patients using a 204-channel, whole-head MEG system. Equivalent current dipoles (ECDs) were calculated for epileptic spikes on MEG according to the single dipole model.
  
  
  RESULTS
  In two patients, MEG showed epileptiform discharges restricted to the unilateral temporal area, corresponding to the EEG spikes. The ECDs calculated from these MEG spikes were clustered in the unilateral temporal lobe. In our third patient, MEG spikes appeared in the right centroparietal area; ECDs were located to the right parietal lobe.
  
  
  CONCLUSIONS
  The sources of epileptiform discharges that were detected in a restricted area were localized to specific parts of the brain cortex. Despite certain limitations (small number of patients; atypical late-onset epilepsy in one) our study suggests that MEG may prove to be a useful tool for investigating electromagnetic features of localized epileptic discharges in patients with LGS. Based on these preliminary results, further studies performed in patients with typical LGS features are justified.
authors.affiliation: Department of Psychiatry and Neurology, Hokkaido University School of Medicine, Sapporo, Japan. kootaroo@m2.dion.ne.jp
authors.forename: Kotaro
authors.initials: K
authors.lastname: Sakurai
authors.forename: Naoaki
authors.initials: N
authors.lastname: Tanaka
authors.forename: Kyousuke
authors.initials: K
authors.lastname: Kamada
authors.forename: Fumiya
authors.initials: F
authors.lastname: Takeuchi
authors.forename: Youji
authors.initials: Y
authors.lastname: Takeda
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Koyama
mesh_terms: D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000503:physiopathology*; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000706:statistics & numerical data; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000503:physiopathology; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000503:physiopathology; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male