title: Rapid eye movement sleep reveals epileptogenic spikes for resective surgery in children with generalized interictal discharges.
abstract: OBJECTIVE
  Epilepsy surgery can be successful in children with extensive congenital or early acquired focal or hemispheric brain lesion on magnetic resonance imaging (MRI) despite generalized interictal epileptiform discharges (IEDs). The aim of this study was to assess if rapid eye movement (REM) sleep reduced generalized IEDs and revealed lateralized IEDs to identify the epileptogenic hemisphere in children with generalized IEDs and normal/subtle changes on MRI.
  
  
  METHODS
  We studied 20 children with generalized IEDs on scalp electroencephalography (EEG) and normal/subtle changes on MRI who underwent intracranial video-EEG for epilepsy surgery. We assessed a minimum of 100 IEDs during REM, non-REM, and wakefulness, and assigned the distribution (generalized, left, or right hemisphere) to each IED. The number of lobes in the resected areas and seizure outcome were compared between 20 children with generalized IEDs and a comparison group of 28 children without generalized IEDs.
  
  
  RESULTS
  The mean occurrence rate of generalized IEDs during REM (37%) was significantly lower than that during non-REM (67%, p < 0.001) and wakefulness (54%, p = 0.003). The number of children whose largest number of IEDs was lateralized in REM was significantly higher than that in non-REM (15 vs. 3 children, 75% vs. 15%, p < 0.001). The hemisphere with lateralized IEDs among three states corresponded with the surgical side in 16 children with generalized IEDs. Seventeen children (85%) with generalized IEDs and 27 (96%) without generalized IEDs underwent resective surgery. Multilobar resection was required for 16 children (94%) with generalized IEDs more frequently than 7 children (26%) without generalized IEDs (p < 0.001). Thirteen children (77%) with generalized IEDs and 19 (73%) without generalized IEDs were seizure-free with a mean of 3.3 years of follow-up.
  
  
  CONCLUSIONS
  Our study demonstrates the importance of assessing REM in children with generalized IEDs as it reveals lateralized epileptogenic spikes. Seizure freedom may be achieved with multilobar resection in these children with generalized IEDs and normal/subtle changes on MRI. Generalized IEDs in children with normal/subtle changes on MRI should not preclude surgical resection.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Okanari
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Shiro
authors.initials: S
authors.lastname: Baba
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
authors.affiliation: Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Elysa
authors.initials: E
authors.lastname: Widjaja
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Satoru
authors.initials: S
authors.lastname: Sakuma
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Cristina Y
authors.initials: CY
authors.lastname: Go
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Jones
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Nishioka
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Shimpei
authors.initials: S
authors.lastname: Oba
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Tasuku
authors.initials: T
authors.lastname: Matsui
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ueno
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Shogo
authors.initials: S
authors.lastname: Ukitsu
authors.affiliation: Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
authors.affiliation: Division of Neurosurgery, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: James M
authors.initials: JM
authors.lastname: Drake
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Donner
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Shelly K
authors.initials: SK
authors.lastname: Weiss
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods*; D012895:Sleep, REM / Q000502:physiology*; D014851:Wakefulness
keywords: Epileptogenic hemisphere; Intracranial video EEG; Lateralized interictal epileptiform discharges; Multilobar resection; Normal/subtle changes on MRI