Low levels of alcohol impair driving simulator performance and reduce perception of crash risk in partially sleep deprived subjects.
OBJECTIVE
Partial sleep deprivation and alcohol consumption are a common combination, particularly among young drivers. We hypothesized that while low blood alcohol concentration (<0.05 g/dL) may not significantly increase crash risk, the combination of partial sleep deprivation and low blood alcohol concentration would cause significant performance impairment.


METHODS
Experimental


METHODS
Sleep Disorders Unit Laboratory


METHODS
20 healthy volunteers (mean age 22.8 years; 9 men).


METHODS
Subjects underwent driving simulator testing at 1 am on 2 nights a week apart. On the night preceding simulator testing, subjects were partially sleep deprived (5 hours in bed). Alcohol consumption (2-3 standard alcohol drinks over 2 hours) was randomized to 1 of the 2 test nights, and blood alcohol concentrations were estimated using a calibrated Breathalyzer. During the driving task subjects were monitored continuously with electroencephalography for sleep episodes and were prompted every 4.5 minutes for answers to 2 perception scales-performance and crash risk.


RESULTS
Mean blood alcohol concentration on the alcohol night was 0.035 +/- 0.015 g/dL. Compared with conditions during partial sleep deprivation alone, subjects had more microsleeps, impaired driving simulator performance, and poorer ability to predict crash risk in the combined partial sleep deprivation and alcohol condition. Women predicted crash risk more accurately than did men in the partial sleep deprivation condition, but neither men nor women predicted the risk accurately in the sleep deprivation plus alcohol condition.


CONCLUSIONS
Alcohol at legal blood alcohol concentrations appears to increase sleepiness and impair performance and the detection of crash risk following partial sleep deprivation. When partially sleep deprived, women appear to be either more perceptive of increased crash risk or more willing to admit to their driving limitations than are men. Alcohol eliminated this behavioral difference.
Banks
Siobhan
S
Unit for Experimental Psychiatry, Division of Sleep and Chronobiology, Department of Psychiatry, University of Pennsylvania School of Medicine, Philadelphia 19104-6021, USA. sbanks@mail.med.upenn.edu
Catcheside
Peter
P
Lack
Leon
L
Grunstein
Ron R
RR
McEvoy
R Doug
RD
D000063:Accidents, Traffic; D000328:Adult; D000428:Alcohol Drinking / Q000009:adverse effects* / Q000453:epidemiology*; D001334:Automobile Driving; D001364:Awareness / Q000187:drug effects*; D004569:Electroencephalography; D000431:Ethanol / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D010468:Perceptual Disorders / Q000453:epidemiology* / Q000209:etiology*; D011930:Reaction Time / Q000187:drug effects; D012892:Sleep Deprivation / Q000097:blood / Q000453:epidemiology*
D000431:Ethanol