Sleepiness, driving, and motor vehicle accidents: A questionnaire-based survey

In Switzerland, the prevalence of an excessive daytime sleepiness (EDS) in drivers undergoing a driving capacity assessment is currently not known. In this study, private and professional drivers were evaluated by means of a paper-based questionnaire, including Epworth Sleepiness Scale, Berlin Questionnaire, and additional questions to sleepiness-related accidents, near-miss accidents, health issues, and demographic data. Of the 435 distributed questionnaires, 128 completed were returned. The response rate was 29%. The mean age of the investigated drivers was 42.5 years (20-85 years). According to the Epworth Sleepiness Scale, 9% of the participants are likely to suffer from excessive daytime sleepiness. An equal percentage has a high risk for obstructive sleep apnea syndrome based on the Berlin Questionnaire. 16% admitted an involuntary nodding off while driving a motor vehicle. This subset of the participants scored statistically significant higher on the Epworth Sleepiness Scale (p = 0.036). 8% of the participants already suffered an accident because of being sleepy while driving. An equal number experienced a sleepiness-related near-miss accident on the road. The study shows that a medical workup of excessive daytime sleepiness is highly recommended in each driver undergoing a driving capacity assessment. Routine application of easily available and time-saving assessment tools such as the Epworth Sleepiness Scale questionnaire could prevent accidents in a simple way. The applicability of the Berlin Questionnaire to screen suspected fatal sleepiness-related motor vehicle accidents is discussed.