title: Individual variation in rapid eye movement sleep is associated with pain perception in healthy women: preliminary data.
abstract: OBJECTIVE
  Sleep-deprivation experiments suggest that sleep loss increases pain sensitivity. It is unclear from preliminary studies, however, whether sleep-related processes are directly associated with pain perception or whether hyperalgesia is due to the secondary effects of sleep deprivation and/or demand characteristics. Consequently, we sought to evaluate relationships between sleep architecture and laboratory measures of pain processing in healthy women, sleeping under normal conditions.
  
  
  METHODS
  Correlational, 2-night polysomnographic study with laboratory pain testing conducted on subsequent days.
  
  
  METHODS
  General clinical research center inpatient unit with private room.
  
  
  METHODS
  Sixteen healthy, female, pain-free good sleepers, free from centrally acting agents (mean age = 24 +/- 4.5 years).
  
  
  RESULTS
  Standard polysomnographic sleep-continuity and architecture variables and subject responses to standard noxious thermal stimuli delivered to the ventral and dorsal surfaces of the forearm via thermal sensory analyzer. Ratings of thermal pain threshold as well as suprathreshold indices of central pain processing (mean/peak ratings and intensity of painful aftersensations) were obtained. Averaging across nights/days, we found significant negative relationships between rapid eye movement sleep latency and suprathreshold pain ratings, ie, measures of heightened central pain processing (r = -.64 to -.73, P < .01). Significant positive relationships were also found between percentage of rapid eye movement sleep and suprathreshold ratings(r = .56 to .66, P < .050).
  
  
  CONCLUSIONS
  These data are the first to demonstrate a relationship between individual variation in rapid eye movement sleep and pain-modulatory processes. The results have implications for the etiology of pain disorders and suggest that neurobiologic substrates regulating sleep may also play a role in central pain processing.
authors.affiliation: Johns Hopkins University School of Medicine, Behavioral Medicine Research Laboratory and Clinic, 600 North Wolfe Street, Meyer 1-108, Baltimore, MD 21287, USA. msmith62@jhmi.edu
authors.forename: Michael T
authors.initials: MT
authors.lastname: Smith
authors.forename: Robert R
authors.initials: RR
authors.lastname: Edwards
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Stonerock
authors.forename: Una D
authors.initials: UD
authors.lastname: McCann
mesh_terms: D000328:Adult; D005260:Female; D006304:Health Status; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D010146:Pain / Q000175:diagnosis / Q000209:etiology*; D010147:Pain Measurement; D017288:Pain Threshold; D017286:Polysomnography; D012720:Severity of Illness Index; D012892:Sleep Deprivation / Q000150:complications; D012893:Sleep Wake Disorders / Q000175:diagnosis / Q000209:etiology; D012895:Sleep, REM / Q000502:physiology*