title: Lateralized interictal epileptiform discharges during rapid eye movement sleep correlate with epileptogenic hemisphere in children with intractable epilepsy secondary to tuberous sclerosis complex.
abstract: OBJECTIVE
  We assessed lateralization of interictal epileptiform discharges (IEDs) in children with intractable epilepsy secondary to tuberous sclerosis complexes (TSCs) during rapid eye movement sleep (R), compared with non-rapid eye movement sleep (NR) and wakefulness (W), to determine epileptogenicity of R-IEDs.
  
  
  METHODS
  We retrospectively studied 23 children with TSC, who underwent prolonged scalp video-electroencephalography (EEG) and magnetic resonance imaging (MRI). We determined the lateralization of ictal EEG, clinical semiology, and the largest tuber on MRI. We analyzed a minimum of 100 IEDs during R, NR, and W to classify right/left/generalized spikes to compare the lateralization with ictal EEG, clinical semiology, and MRI.
  
  
  RESULTS
  R-IEDs were lateralized in 22 patients (96%), W-IEDs in 19 (83%), and NR-IEDs in 16 (70%). Ictal EEGs were lateralized in 15 patients (65%) and clinical semiology in 5 (22%). Ictal EEG lateralization was concordant to R-IEDs in 14 patients (93%), W-IEDs in 11 (73%), and NR-IEDs in 10 (67%). The lateralization of clinical semiology was concordant with R-IEDs in 4 (80%), W-IEDs in 3 (60%), and NR-IEDs in 2 (40%). MRI lateralization of the largest tuber was concordant with R-IEDs in 16 (70%), W-IEDs in 12 (52%), and NR-IEDs in 11 (48%). Thirteen patients (57%) underwent resective surgery, the hemisphere of which was concordant with R-IEDs in 13 (100%), W-IEDs in 8 (62%), and NR-IEDs in 8 (62%). Nine (69%) of them achieved good seizure control after surgery.
  
  
  CONCLUSIONS
  R provoked the most lateralized IEDs compared to NR and W in children with TSC. Lateralization of R-IEDs corresponded with the hemisphere of ictal EEG and largest tuber, and can be used to identify surgical candidacy in TSC children with intractable epilepsy.
authors.affiliation: Division of Neurology, The Hospital for Sick Children, Toronto, ON, Canada. ayako.ochi@sickkids.ca
authors.forename: Ayako
authors.initials: A
authors.lastname: Ochi
authors.forename: Ryan
authors.initials: R
authors.lastname: Hung
authors.forename: Shelly
authors.initials: S
authors.lastname: Weiss
authors.forename: Elysa
authors.initials: E
authors.lastname: Widjaja
authors.forename: Tonia
authors.initials: T
authors.lastname: To
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nawa
authors.forename: Taiki
authors.initials: T
authors.lastname: Shima
authors.forename: Cristina
authors.initials: C
authors.lastname: Go
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Akiyama
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Donner
authors.forename: James
authors.initials: J
authors.lastname: Drake
authors.forename: James T
authors.initials: JT
authors.lastname: Rutka
authors.forename: O Carter
authors.initials: OC
authors.lastname: Snead
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Otsubo
mesh_terms: D001921:Brain / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D004827:Epilepsy / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging; D008297:Male; D012189:Retrospective Studies; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology*; D014402:Tuberous Sclerosis / Q000150:complications* / Q000473:pathology / Q000503:physiopathology