title: Intracerebral recordings of nocturnal hyperkinetic seizures: demonstration of a longer duration of the pre-seizure sleep spindle.
abstract: OBJECTIVE
  Nocturnal frontal lobe epilepsy (NFLE) seizures occur primarily during non-rapid eye movement sleep stage 2. We observed in several patients rhythms of same localization and frequency as sleep spindles, immediately preceding and sometimes continuing at seizure onsets. We aimed to study the link between sleep spindles and seizure onsets.
  
  
  METHODS
  We used intracerebral stereo-EEG ictal recordings of two MRI-negative patients with clinically defined NFLE. For each of the six studied seizures, sustained activity in the frontal sleep spindle frequency (12Hz) was observed around seizure onset. The duration of this pre-seizure sleep spindle was compared to that of the 10 preceding sleep spindles.
  
  
  RESULTS
  The pre-seizure sleep spindles were clearly of longer duration than the "interictal" sleep spindles for all seizures. This sustained pre-seizure 12Hz activity could be differentiated from normal awakenings, and showed no spatial relation to the ictal onset.
  
  
  CONCLUSIONS
  We demonstrated a functional alteration of the sleep spindle-generating thalamocortical loop concomitant with the seizure onsets. This defect may also be involved in seizure generation.
  
  
  CONCLUSIONS
  A thalamic participation in NFLE pathogenesis is likely in our two patients. The study of additional patients will allow to evaluate the role of the thalamocortical circuits in NFLE.
authors.affiliation: Department of Neurology, University Hospital and Medical School of Geneva, 24 rue Micheli-du-Crest, 1211 Geneva 14, Switzerland. Fabienne.Picard1@hcuge.ch
authors.forename: F
authors.initials: F
authors.lastname: Picard
authors.forename: P
authors.initials: P
authors.lastname: Mégevand
authors.forename: L
authors.initials: L
authors.lastname: Minotti
authors.forename: P
authors.initials: P
authors.lastname: Kahane
authors.forename: P
authors.initials: P
authors.lastname: Ryvlin
authors.forename: M
authors.initials: M
authors.lastname: Seeck
authors.forename: C M
authors.initials: CM
authors.lastname: Michel
authors.forename: G
authors.initials: G
authors.lastname: Lantz
mesh_terms: D000293:Adolescent; D001931:Brain Mapping; D002648:Child; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography / Q000379:methods; D012640:Seizures / Q000503:physiopathology*; D012890:Sleep