title: Sleep stage dynamics in fibromyalgia patients and controls.
abstract: OBJECTIVE
  To determine whether previously described sleep stage dynamics, reflecting the mean duration of specific sleep stages, may have clinical utility in a sample of patients with fibromyalgia syndrome (FMS) and controls.
  
  
  METHODS
  Women with FMS (n=15, screened to exclude other sleep disorders) and age-matched women in good health (n=15) were studied with nocturnal polysomnography, multiple sleep latency tests, 2-week pain diaries, and a measure of current pain intensity.
  
  
  RESULTS
  The FMS subjects, in comparison to controls, did not show differences in several common polysomnographic measures, except for increased numbers of stage shifts (126+/-27 vs. 107+/-22, p=.042). Mean durations for episodes of total sleep, stage 1 sleep, stage 3/4 sleep, and rapid eye movement sleep failed to distinguish FMS and control subjects (Wilcoxon rank sum tests, p>.10 for each), but those for stage 2 sleep were shorter in the FMS subjects (p=.006), possibly because transitions to stage 3/4 sleep occurred more quickly (p=.036). Shorter stage 2 sleep durations predicted higher pain diary scores (Spearman rho=-.56, p=.0014) and current pain intensity (rho=-.71, p<0.0001).
  
  
  CONCLUSIONS
  Sleep stage dynamic, and, more specifically, shorter durations of sleep stage 2 periods, distinguish FMS and control female subjects and may predict pain levels experienced in FMS. Analysis of the lengths of individual sleep stages, in addition to the usual sleep stage amounts and percentages listed in standard polysomnogram reports, may have clinical utility.
authors.affiliation: Michigan Tech Research Institute, Michigan Technological University, 3600 Green Court, Suite 100, Ann Arbor, MI 48105, USA. joseph.burns@mtu.edu
authors.forename: Joseph W
authors.initials: JW
authors.lastname: Burns
authors.forename: Leslie J
authors.initials: LJ
authors.lastname: Crofford
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Chervin
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D004569:Electroencephalography; D005260:Female; D005356:Fibromyalgia / Q000503:physiopathology*; D006801:Humans; D008875:Middle Aged; D010147:Pain Measurement; D017286:Polysomnography; D011237:Predictive Value of Tests; D012894:Sleep Stages / Q000502:physiology*; D013997:Time Factors