The Role of Sleep-Disordered Breathing, Daytime Sleepiness, and Impaired Performance in Motor Vehicle Crashes-A Case Control Study

Study Objective: To examine levels of sleep-disordered breathing, daytime sleepiness, and impaired performance in 60 motor vehicle crash drivers and 60 controls matched for age, gender, and body mass index. Measurements and Results: All participants underwent polysomnography and daytime function assessments. Cases reported significantly higher levels of driver sleepiness (% sleepiness: mean ± SD; cases: 26 ± 17%; controls: 16 ± 12%; p = 0.003) and demonstrated slower reaction times on a sustained attention task (p = 0.02). There was a trend for more objective sleepiness in cases (maintenance of wakefulness test: cases: 17 ± 4 minutes; controls: 18 ± 3 minutes, p = 0.06) despite no differences in general subjective sleepiness (Epworth score: cases: 8 ± 4; controls: 8 ± 4; p = 0.93). There were no significant differences in polysomnography measures between groups (apneas + hypopneas per hour slept: cases: 8 ± 9; controls: 9 ± 16; p = 0.89; arousals per hour slept: cases: 18 ± 8; controls: 21 ± 12; p = 0.11). Conclusion: Crash drivers demonstrated significantly more driver sleepiness, slower reaction times and a trend for greater objective sleepiness compared with well-matched controls. However, the findings in crash drivers were independent of medical causes of sleep fragmentation, with both cases and controls showing moderate levels of unrecognized mild sleep-disordered breathing. Crash prevention strategies should focus on increasing personal awareness of the risks of sleepiness behind the wheel in all individuals.

KEYWORDS

Sleep-disordered breathing - traffic crashes - sleepiness - performance - MWT

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