title: EEG Functional Connectivity Prior to Sleepwalking: Evidence of Interplay Between Sleep and Wakefulness.
abstract: Although sleepwalking (somnambulism) affects up to 4% of adults, its pathophysiology remains poorly understood. Sleepwalking can be preceded by fluctuations in slow-wave sleep EEG signals, but the significance of these pre-episode changes remains unknown and methods based on EEG functional connectivity have yet to be used to better comprehend the disorder.
  
  
  
  We investigated the sleep EEG of 27 adult sleepwalkers (mean age: 29 ± 7.6 years) who experienced a somnambulistic episode during slow-wave sleep. The 20-second segment of sleep EEG immediately preceding each patient's episode was compared with the 20-second segment occurring 2 minutes prior to episode onset.
  
  
  
  Results from spectral analyses revealed increased delta and theta spectral power in the 20 seconds preceding the episodes' onset as compared to the 20 seconds occurring 2 minutes before the episodes. The imaginary part of the coherence immediately prior to episode onset revealed (1) decreased delta EEG functional connectivity in parietal and occipital regions, (2) increased alpha connectivity over a fronto-parietal network, and (3) increased beta connectivity involving symmetric inter-hemispheric networks implicating frontotemporal, parietal and occipital areas.
  
  
  
  Taken together, these modifications in EEG functional connectivity suggest that somnambulistic episodes are preceded by brain processes characterized by the co-existence of arousal and deep sleep.
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychology, Université de Montréal, Montréal, Canada.
authors.forename: Marie-Ève
authors.initials: MÈ
authors.lastname: Desjardins
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychology, Université de Montréal, Montréal, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Carrier
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|École de technologie supérieure, Department of Electrical Engineering, Montréal, Canada.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Lina
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychology, Université du Québec à Montréal, Montréal, Canada.
authors.forename: Maxime
authors.initials: M
authors.lastname: Fortin
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychology, Université de Montréal, Montréal, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Gosselin
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychiatry, Université de Montréal, Montréal, Canada.
authors.forename: Jacques
authors.initials: J
authors.lastname: Montplaisir
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur de Montréal, Montréal, Canada.|Department of Psychology, Université de Montréal, Montréal, Canada.
authors.forename: Antonio
authors.initials: A
authors.lastname: Zadra
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000503:physiopathology; D010296:Parietal Lobe / Q000503:physiopathology; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*; D013009:Somnambulism / Q000503:physiopathology*; D013997:Time Factors; D014851:Wakefulness / Q000502:physiology*
keywords: Electrophysiology; Functional connectivity; Parasomnias; Pathophysiology; Slow-wave sleep; Somnambulism