title: Auditory arousal responses and thresholds during REM and NREM sleep of sleepwalkers and controls.
abstract: BACKGROUND
  It has been suggested that sleepwalkers are more difficult to awaken from sleep than are controls. However, no quantified comparisons have been made between these two populations. The main goal of this study was to assess arousal responsiveness via the presentation of auditory stimuli (AS) in sleepwalkers and controls during normal sleep and recovery sleep following sleep deprivation.
  
  
  METHODS
  Ten adult sleepwalkers and 10 age-matched control subjects were investigated. After a screening night, participants were presented with AS during slow-wave sleep (SWS), REM, and stage 2 sleep either during normal sleep or daytime recovery sleep following 25 h of sleep deprivation. The AS conditions were then reversed one week later.
  
  
  RESULTS
  When compared to controls sleepwalkers necessitated a significantly higher mean AS intensity (in dB) to induce awakenings and arousal responses during REM sleep whereas the two groups' mean values did not differ significantly during SWS and stage 2 sleep. Moreover, when compared to controls sleepwalkers had a significantly lower mean percentage of AS that induced arousal responses during REM sleep while the opposite pattern of results was found during SWS.
  
  
  CONCLUSIONS
  The data indicate that sleepwalkers have a higher auditory awakening threshold than controls, but only for REM sleep. These findings may reflect a compensatory mechanism of the homeostatic process underlying sleep regulation during sleepwalkers' REM sleep in reaction to their difficulties maintaining consolidated periods of NREM sleep.
authors.affiliation: Center for Advanced Research in Sleep Medicine, Hôpital du Sacré-Cœur, Montréal, Québec, Canada.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Pilon
authors.forename: Alex
authors.initials: A
authors.lastname: Desautels
authors.forename: Jacques
authors.initials: J
authors.lastname: Montplaisir
authors.forename: Antonio
authors.initials: A
authors.lastname: Zadra
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001143:Arousal / Q000502:physiology*; D001309:Auditory Threshold / Q000502:physiology; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology*; D013009:Somnambulism / Q000503:physiopathology*