title: Fatigue: The forgotten symptom of sleep apnea.
abstract: OBJECTIVE
  The present investigation was designed to explore the role and implications of both daytime sleepiness and fatigue in obstructive sleep apnea syndrome with respect to sleep, perceived health quality, and psychological functioning.
  
  
  METHODS
  Our participants consisted of two groups: 124 older community volunteers who completed a polysomnographic sleep study and were diagnosed with sleep apnea, and 19 healthy controls. All participants completed self-report measures of sleepiness, fatigue, sleep quality, health quality, and psychological functioning.
  
  
  RESULTS
  The apnea sample was divided according to clinically relevant cut-offs on sleepiness and fatigue. When those with mid-range scores were ruled out, the following groups remained: low sleepiness/low fatigue (LL, n=23), high sleepiness/high fatigue (HH, n=28), high sleepiness/low fatigue (HS, n=10) and low sleepiness/high fatigue (HF, n=13). The respiratory disturbance index did not differ significantly among these groups and only the two highly fatigued groups (HH and HF) experienced significantly lower average oxygen saturation than the control group. Analyses revealed that the HH group was significantly worse than the LL and control groups on most sleep, health quality, and psychological measures. On these same measures, the groups for whom fatigue was low (LL and HS), regardless of sleepiness, were similar to controls.
  
  
  CONCLUSIONS
  When patients with sleep apnea are classified into different sleepiness/fatigue categories, the results show that high fatigue is associated with more severe dysfunction than high sleepiness. The current debate on whether to treat apnea patients with low sleepiness needs to consider the impact of fatigue.
authors.affiliation: Jewish General Hospital, Montreal, Canada. sally.bailes@mcgill.ca
authors.forename: Sally
authors.initials: S
authors.lastname: Bailes
authors.forename: Eva
authors.initials: E
authors.lastname: Libman
authors.forename: Marc
authors.initials: M
authors.lastname: Baltzan
authors.forename: Roland
authors.initials: R
authors.lastname: Grad
authors.forename: Ibrahim
authors.initials: I
authors.lastname: Kassissia
authors.forename: Laura
authors.initials: L
authors.lastname: Creti
authors.forename: Dorrie
authors.initials: D
authors.lastname: Rizzo
authors.forename: Rhonda
authors.initials: R
authors.lastname: Amsel
authors.forename: Catherine S
authors.initials: CS
authors.lastname: Fichten
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D057566:Self Report; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000175:diagnosis; D011795:Surveys and Questionnaires