The interactive effects of extended wakefulness and low-dose alcohol on simulated driving and vigilance.
OBJECTIVE
Sleep deprivation and alcohol both impair driving performance. This study assessed the interactive effect of low-dose alcohol and extended wakefulness.


METHODS
Repeated-measures, crossover design evaluating psychomotor and driving function in a non-sleep-deprived state and after extended wakefulness with and without low-dose alcohol.


METHODS
Teaching hospital sleep laboratory.


METHODS
Nineteen volunteer professional drivers.


METHODS
Driving simulation (AusEd) and the Psychomotor Vigilance Task (PVT) were measured in a rested state (12-15 hours awake) and after extended wakefulness (18-21 hours awake) during two sessions. Alcohol was administered during one session, with performance measured at blood alcohol concentrations (BAC) of 0.00%, 0.03%, and 0.05% in a non-sleep-deprived state, and at 0.03% after extended wakefulness (at 01:00 and 03:00). During the second session, tests were performed at the same times without alcohol.


RESULTS
The combination of extended wakefulness and low-dose alcohol had significant deleterious effects on reaction time and lapses (PVT) and variation in lane position and speed (AusEd). Extended wakefulness (18-21 hours awake) combined with low-dose alcohol (0.03% BAC) resulted in more lapses (t = -2.75, P < 0.05) and greater variation in lane position (t = -3.94, P < 0.01) and speed (t = -2.79, P < 0.05) than did a BAC of 0.05% in a rested state.


CONCLUSIONS
The combination of legal low-dose alcohol and extended wakefulness results in impairment worse than that at an alcohol level known to increase accident risk. Avoiding alcohol when driving after extended wakefulness may reduce accident risk.
Howard
Mark E
ME
Institute for Breathing & Sleep, Department of Respiratory & Sleep Medicine, Austin Health, Melbourne, Australia. mark.howard@austin.org.au
Jackson
Melinda L
ML
Kennedy
Gerard A
GA
Swann
Philip
P
Barnes
Maree
M
Pierce
Robert J
RJ
D000328:Adult; D000428:Alcohol Drinking / Q000503:physiopathology*; D000704:Analysis of Variance; D001334:Automobile Driving; D003198:Computer Simulation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010468:Perceptual Disorders / Q000209:etiology / Q000503:physiopathology; D011930:Reaction Time; D016037:Single-Blind Method; D012892:Sleep Deprivation / Q000150:complications*; D013647:Task Performance and Analysis; D014851:Wakefulness / Q000502:physiology*