Abstract
STUDY OBJECTIVES: Although excessive daytime sleepiness (EDS) has a crucial impact on motor vehicle crashes (MVCs), the assessment of subjective sleepiness as a screening tool for MVC has limitations. Objective daytime sleepiness may be a better predictor of MVCs rather than subjective daytime sleepiness. Therefore, we aimed to examine the association of psychomotor vigilance as a surrogate marker of objective sleepiness and subjective sleepiness with MVCs in a prospective cohort study of the general population. METHODS: The study participants were 903 community-dwelling Japanese followed up 5 years after baseline and ascertained history of MVC over the study period. Psychomotor vigilance was measured by the psychomotor vigilance test and categorized into quartiles by the reciprocal of the mean reaction time (mean1/RT). Subjective EDS was defined using the Japanese version of the Epworth Sleepiness Scale. Multivariable logistic regression analysis was used to examine the association between mean1/RT and MVC after stratification by subjective EDS. RESULTS: The multivariable-adjusted odds ratio (95% confidence interval) for MVC among the highest quartile group of mean1/RT was 0.31 (0.17-0.57), compared with the lowest group (P for trend < .01). After stratification by subjective EDS, the significant association was found only among the nonsubjective EDS group (P for trend < .01) and not among the subjective EDS group (P for trend = .16). CONCLUSIONS: Decreased psychomotor vigilance measured by the psychomotor vigilance test was associated with a higher risk of MVCs, and the association was more evident among the nonsubjective EDS group. The psychomotor vigilance test may be useful to prevent sleep-related MVCs in the general population, particularly for individuals without subjective EDS. CITATION: Matsuo R, Tanigawa T, Oshima A, et al. Decreased psychomotor vigilance is a risk factor for motor vehicle crashes irrespective of subjective daytime sleepiness: the Toon Health Study. J Clin Sleep Med. 2023;19(2):319-325.