title: On the potential clinical relevance of the length of arousals from sleep in patients with obstructive sleep apnea.
abstract: OBJECTIVE
  To assess, in individuals referred for evaluation of obstructive sleep apnea, the potential clinical significance of brief versus longer arousals from sleep.
  
  
  METHODS
  Full-night polysomnographic tracings from 100 patients referred for evaluation of obstructive sleep apnea were analyzed to delineate the duration of each arousal event. These data were then correlated to the patient's subjective perception of sleepiness as estimated by the Epworth Sleepiness Scale (ESS).
  
  
  RESULTS
  A significant relationship (p < .0001, r(2) = .167) was noted between the frequency of the longer arousals (> 15 seconds) and the ESS. This relationship was significant, but distinctly weaker (p = .004, r(2) = .073), with the shorter arousals (3-15 seconds); moreover, the association with the brief arousals failed to remain significant (p = .678) after controlling for the effect of the longer arousals.
  
  
  CONCLUSIONS
  Individuals with obstructive sleep apnea experience frequent respiratory event associated cortical arousals, many of which are greater than 15 seconds in duration. These longer arousals, which, in this study, constituted 18.4% of all arousals and accounted for 37.5% of the total arousal time, correlate more closely with the ESS than does the frequency or time attributable to the more numerous brief arousals. This suggests that these more-prolonged arousal events may have a greater impact on the restorative aspect of sleep, or on the perception thereof.
authors.affiliation: The Tampa Sleep Center, University Community Hospital, Department of Medicine, University of South Florida, Tampa, FL 33613, USA. thetampasleepcenter@att.net
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Schwartz
authors.forename: Pat
authors.initials: P
authors.lastname: Moxley
mesh_terms: D001143:Arousal / Q000502:physiology*; D015992:Body Mass Index; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005121:Extremities / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D017286:Polysomnography; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology; D013997:Time Factors