title: Moderate sleep restriction in treated older male OSA participants: greater impairment during monotonous driving compared with controls.
abstract: OBJECTIVE
  To examine the effects on monotonous driving of normal sleep versus one night of sleep restriction in continuous positive airway pressure (CPAP) treated obstructive sleep apnoea (OSA) patients compared with age matched healthy controls.
  
  
  METHODS
  Nineteen CPAP treated compliant male OSA patients (OSA-treated patients (OPs)), aged 50-75 years, and 20 healthy age-matched controls underwent both a normal night's sleep and sleep restriction to 5h (OPs remained on CPAP) in a counterbalanced design. All participants completed a 2h afternoon monotonous drive in a realistic car simulator. Driving was monitored for sleepiness-related minor and major lane deviations, with 'safe' driving time being total time driven prior to first major lane deviation. EEGs were recorded continuously, and subjective sleepiness ratings were taken at regular intervals throughout the drive.
  
  
  RESULTS
  After a normal night's sleep, OPs and controls did not differ in terms of driving performance or in their ability to assess the levels of their own sleepiness, with both groups driving 'safely' for approximately 90 min. However, after sleep restriction, OPs had a significantly shorter (65 min) safe driving time and had to apply more compensatory effort to maintain their alertness compared with controls. They also underestimated the enhanced sleepiness. Nevertheless, apart from this caveat, there were generally close associations between subjective sleepiness, likelihood of a major lane deviation and EEG changes indicative of sleepiness.
  
  
  CONCLUSIONS
  With a normal night's sleep, effectively treated older men with OSA drive as safely as healthy men of the same age. However, after restricted sleep, driving impairment is worse than that of controls. This suggests that, although successful CPAP treatment can alleviate potential detrimental effects of OSA on monotonous driving following normal sleep, these patients remain more vulnerable to sleep restriction.
authors.affiliation: Sleep Research Centre, Loughborough University, Leicestershire LE11 3TU, UK. ashleigh.filtness@monash.edu
authors.forename: Ashleigh J
authors.initials: AJ
authors.lastname: Filtness
authors.forename: Louise A
authors.initials: LA
authors.lastname: Reyner
authors.forename: James A
authors.initials: JA
authors.lastname: Horne
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control; D000368:Aged; D000375:Aging / Q000502:physiology; D000513:Alpha Rhythm; D001334:Automobile Driving; D001611:Beta Rhythm; D045422:Continuous Positive Airway Pressure; D006801:Humans; D008297:Male; D008875:Middle Aged; D010465:Perception / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D012892:Sleep Deprivation / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D012894:Sleep Stages / Q000502:physiology*; D013826:Theta Rhythm; D014584:User-Computer Interface