title: Visual vigilance in drivers with obstructive sleep apnea.
abstract: OBJECTIVE
  To determine the effects of obstructive sleep apnea (OSA) on visual vigilance during simulated automobile driving.
  
  
  METHODS
  Twenty-five drivers with OSA and 41 comparison drivers participated in an hour-long drive in a high-fidelity driving simulator. Drivers responded to light targets flashed at seven locations across the forward horizon. Dependent measures were percent correct [hit rate (HR)] and reaction time (RT). Self-assessment of sleepiness used the Stanford Sleepiness Scale (SSS) before and after the drive and the Epworth Sleepiness Scale (ESS).
  
  
  RESULTS
  OSA drivers showed reduced vigilance based on lower HR than comparison drivers, especially for peripheral targets (80.7+/-14.8% vs. 86.7+/-8.8%, P=.03). OSA drivers were sleepier at the end of the drive than comparison drivers (SSS=4.2+/-1.2 vs. 3.6+/-1.2, P=.03), and increased sleepiness correlated with decreased HR only in those with OSA (r=-0.49, P=.01). Lower HR and higher post-drive SSS predicted greater numbers of driving errors in all subjects. Yet, ESS, predrive SSS, and most objective measures of disease severity failed to predict driving and vigilance performance in OSA.
  
  
  CONCLUSIONS
  Reduced vigilance for peripheral visual targets indicates that OSA drivers have restriction of their effective field of view, which may partly explain their increased crash risk. This fatigue-related decline in attention is predicted by increased subjective sleepiness during driving. These findings may suggest a means of identifying and counseling high-risk drivers and aid in the development of in-vehicle alerting and warning devices.
authors.affiliation: Department of Neurology, University of Iowa, Iowa City, IA 52242, USA. jon-tippin@uiowa.edu
authors.forename: Jon
authors.initials: J
authors.lastname: Tippin
authors.forename: JonDavid
authors.initials: J
authors.lastname: Sparks
authors.forename: Matthew
authors.initials: M
authors.lastname: Rizzo
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology*; D001248:Asthenopia / Q000453:epidemiology / Q000503:physiopathology; D001334:Automobile Driving / Q000706:statistics & numerical data*; D006970:Disorders of Excessive Somnolence / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D017286:Polysomnography; D015995:Prevalence; D011930:Reaction Time / Q000502:physiology; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D014584:User-Computer Interface; D014794:Visual Fields / Q000502:physiology; D014796:Visual Perception