Neurocognitive Consequences of Sleep Deprivation

Jeffrey S. Durmer, MD, PhD; David F. Dinges, PhD


Semin Neurol. 2005;25(1):117-129. 

In This Article

Sleep Deprivation and Accident Risk

Sleep deprivation increases the risk of human-error related accidents.[1] The overall prevalence of insufficient sleep in adults has been estimated at 20%.[2] The effects of insufficient sleep on cognitive processing is described below; however, the most common measure in population based studies is daytime sleepiness. A recent study to determine the prevalence of daytime sleepiness, using interviews over 5.5 years to follow 1007 randomly selected young adults age 21 to 30 years, was performed in southeast Michigan.[3] They found the average nocturnal sleep time during weekdays was 6.7 hours and on weekends was 7.4 hours. Sleepiness was inversely proportional to hours slept, and difficulty falling asleep was more prevalent in single adults with a full-time job. Studies in young adults indicate that 8 to 9 hours of extended nocturnal sleep are needed to resolve sleepiness caused by decreased sleep time.[4,5] The apparent chronic partial sleep deprivation of the young adults surveyed in 1997 complements statistics that find young drivers, especially males, at much higher risk for drowsy driving and sleep-related crashes.[6,7,8]

Accidents related to sleep deprivation have been estimated to have an annual economic impact of $43 to $56 billion.[9] Motor vehicle accidents related to fatigue, drowsy driving, and falling asleep at the wheel are particularly common but often underestimated.[10,11] Increased time awake, nocturnal circadian phase, reduced sleep duration, prolonged driving duration, and use of soporific medications have all been found to contribute to the occurrence of drowsy-driving and fatigue-related motor vehicle crashes.[6,12,13] Studies of shift workers,[14,15,16] truck drivers,[17,18,19] medical residents,[20,21,22] and airline pilots[23,24,25,26] show an increased risk of crashes or near misses due to sleep deprivation.

Sleepiness-related motor vehicle crashes have a fatality rate and injury severity level similar to alcohol-related crashes.[6] Sleep deprivation has been shown to produce psychomotor impairments equivalent to those induced by alcohol consumption at or above the legal limit.[27] For example, in a study of simulated driving performance, impairments in lane-keeping ability after a night without sleep were equivalent to those observed at blood alcohol content (BAC) of 0.07%.[28] Similarly, a study of professional truck drivers found that deficits in performance accuracy and reaction time at 28 hours of sleep deprivation were equivalent to those found after alcohol intoxication (BAC at 0.1%).[29] It appears that as continuous daytime waking exceeds 16 hours, psychomotor performance deficits increase to levels equivalent to BACs between 0.05 and 0.1%.[27,29]

Sleep deprivation poses a risk to safe operation in all modes of transportation and to performance in other safety-sensitive activities. By studying the impact of sleep deprivation on cognitive abilities, investigators have revealed plausible neurocognitive explanations for the observed behavioral decrements in different operational environments.


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