A Turn in the Road: Real-life Driving Differences in Obstructive Sleep Apnoea and Excessive Daytime Sleepiness

Background: A driver with untreated obstructive sleep apnoea (OSA) is at an increased relative risk of crashing their vehicle. Nonetheless, the chance of any individual being involved in a collision remains low and it is not clear how we can identify which drivers with OSA are most at risk. Since motion detection is used by insurers to assess risky driving, we sought to characterise how driving changes with OSA and daytime sleepiness in real life. Methods: Ninety-one recruited participants (mean age 51 [22 to 77] years; 35% female; mean ESS 12.5, mean ODI 15/h) completed 7,834 journeys (mean duration 15.6 minutes), yielding 508,544 driving events. Participants were recruited at referral to our sleep service and installed a smartphone app that recorded driving data, at least until diagnostic outcomes were known. Data were analysed for driving events of braking, accelerating and turning using linear mixed-effects models against participant data including age, sex, BMI, Epworth Sleepiness Scale (ESS), oxygen desaturation index (ODI), time into trip and journey duration. Findings: ESS and ODI combined showed all clinical groups robustly differed from non-OSA / non-EDS, [ODI<5 / ESS<11] in turning behaviour. Younger age was linked to different, potentially riskier behaviour, while ESS and ODI, when analysed independently, showed no robust association with identifiable differences in driving. Interpretation: Smartphone telematics can distinguish people with self-reported sleepiness and OSA from non-OSA / non-EDS individuals, via turning behaviour. This supports shifting emphasis from diagnosis and self-report towards objective behavioural indicators of impairment. Combining telematics with cognitive, physiological and/or subjective measures could yield practical criteria to improve crash-risk assessments and provide objective support for decisions around driving cessation or continuance. Funding: This research was supported by funds from the Royal Papworth Charity and Consciousness and Cognition Lab.