title: Slow eyelid closure as a measure of driver drowsiness and its relationship to performance.
abstract: OBJECTIVE
  Slow eyelid closure is recognized as an indicator of sleepiness in sleep-deprived individuals, although automated ocular devices are not well validated. This study aimed to determine whether changes in eyelid closure are evident following acute sleep deprivation as assessed by an automated device and how ocular parameters relate to performance after sleep deprivation.
  
  
  METHODS
  Twelve healthy professional drivers (45.58 ± 10.93 years) completed 2 randomized sessions: After a normal night of sleep and after 24 h of total sleep deprivation. Slow eye closure (PERCLOS) was measured while drivers performed a simulated driving task.
  
  
  RESULTS
  Following sleep deprivation, drivers displayed significantly more eyelid closure (P < .05), greater variation in lane position (P < .01) and more attentional lapses (P < .05) compared to after normal sleep. PERCLOS was moderately associated with variability in both vigilance performance (r = 0.68, P < .05) and variation in lane position on the driving task (r = 0.61, P < .05).
  
  
  CONCLUSIONS
  Automated ocular measurement appears to be an effective means of detecting impairment due to sleep loss in the laboratory.
authors.affiliation: a Institute for Breathing and Sleep, Austin Health , Melbourne , Australia.|b School of Health Sciences, RMIT University , Melbourne , Australia.
authors.forename: Melinda L
authors.initials: ML
authors.lastname: Jackson
authors.affiliation: c MedStar Health Research Institute, Washington Hospital Center , Washington, DC.
authors.forename: Susan
authors.initials: S
authors.lastname: Raj
authors.affiliation: d School of Psychology, University of Wollongong , Wollongong , Australia.
authors.forename: Rodney J
authors.initials: RJ
authors.lastname: Croft
authors.affiliation: e Centre for Human Psychopharmacology, Swinburne University of Technology , Hawthorn , Australia.
authors.forename: Amie C
authors.initials: AC
authors.lastname: Hayley
authors.affiliation: e Centre for Human Psychopharmacology, Swinburne University of Technology , Hawthorn , Australia.|f Department of Psychology , Swansea University , Swansea, Wales , UK.
authors.forename: Luke A
authors.initials: LA
authors.lastname: Downey
authors.affiliation: g School of Psychology, Counselling & Psychotherapy, Cairnmillar Institute , Melbourne , Australia.
authors.forename: Gerard A
authors.initials: GA
authors.lastname: Kennedy
authors.affiliation: a Institute for Breathing and Sleep, Austin Health , Melbourne , Australia.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Howard
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology; D001334:Automobile Driving / Q000523:psychology* / Q000706:statistics & numerical data; D003198:Computer Simulation; D005143:Eyelids / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012890:Sleep; D012892:Sleep Deprivation / Q000523:psychology*; D012894:Sleep Stages / Q000502:physiology*; D013647:Task Performance and Analysis; D055815:Young Adult
keywords: professional drivers; reaction time; simulated driving; sleep deprivation; slow eyelid closure; standard deviation of lateral position; vigilance