title: Spatial relationship between fast and slow components of ictal activities and interictal epileptiform discharges in epileptic spasms.
abstract: OBJECTIVE
  We analyzed the spatial distribution and concordance of fast (>10Hz) and slow (<5Hz) electroencephalogram (EEG) components of ictal activities and interictal epileptiform discharges (IIED) recorded by intracranial video EEG (IVEEG) in children with epileptic spasms (ES).
  
  
  METHODS
  We studied eight children with ES, who underwent IVEEG before resective surgery for epilepsy. We quantified the root-mean-square (RMS) amplitude of the fast and slow components of ictal activities during ES and IIED. We compared the concordance between the spatial distributions of the fast and slow components of ES and IIED.
  
  
  RESULTS
  There was a larger concordance between the spatial distributions of the fast and slow components in IIED than in ES (p=0.0206 and 0.0401).
  
  
  CONCLUSIONS
  The spatial concordance between the fast and slow EEG components was significantly different between ES and IIED.
  
  
  CONCLUSIONS
  The mechanisms underlying the generation of slow EEG components may differ between ES and IIED. The slow EEG components of ES might indicate an extensive epileptic network involving remote symptomatic zones for ES in either the cortical or subcortical areas. The high spatial concordance between the fast and slow components of IIED suggests the involvement of a local inhibitory process within the epileptic cortex.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada; Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Akiyama
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada; Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
authors.forename: Mari
authors.initials: M
authors.lastname: Akiyama
authors.affiliation: Department of Child Neurology, Okayama University Hospital, Okayama, Japan.
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kobayashi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada; Department of Child Neurology, Seirei Hamamatsu Hospital, Shizuoka, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Okanishi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Cyrus G
authors.initials: CG
authors.lastname: Boelman
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Dragos A
authors.initials: DA
authors.lastname: Nita
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Cristina Y
authors.initials: CY
authors.lastname: Go
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.affiliation: Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada.
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
authors.affiliation: Division of Neurosurgery, The Hospital for Sick Children, Toronto, Canada.
authors.forename: James M
authors.initials: JM
authors.lastname: Drake
authors.affiliation: Department of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Sylvester
authors.initials: S
authors.lastname: Chuang
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Canada. Electronic address: hiroshi.otsubo@sickkids.ca.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
mesh_terms: D000293:Adolescent; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D013997:Time Factors
keywords: Epileptic spasms; Fast waves; Interictal epileptiform discharges; Slow waves; Spatial distribution