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.