A new clinical tool to assess fitness-to-drive in obstructive sleep apnea

Following a screening visit and obtaining informed consent, participants undergo one week of activity monitoring and sleep diary assessments, followed by a two-day experimental laboratory protocol. Following a screening visit and obtaining informed consent, participants undergo one week of activity monitoring and sleep diary assessments, followed by a two-day experimental laboratory protocol. The experimental laboratory protocol starts in the evening of day 1 with an overnight baseline polysomnography assessment. On the second day, participants will be woken up between 6:00 and 6:30 am and will remain awake for an extended period of 22 hours. Throughout the protocol, adherence to remain awake will be monitored with CCTV and direct surveillance. All participants will undergo a 90-minute assessment of driving simulator tests (primary performance outcome) at baseline (~2 hours awake at 8:00 am) and with extended wakefulness (~19 hours wake at 1:00 am), which is administered and monitored by the researcher. For the duration of the test, the participant will be seated behind a desk with foot pedals and a steering wheel behind a 22-inch monitor. Selected candidate biomarker measures are obtained in 5 blocks of neurobehavioral test batteries, 4 maintenance of wakefulness tests (MWT), and two blood samples obtained prior and after the two driving tests respectively. The neurobehavioral tests commence at 9:00 and are repeated every 2 hours. The MWT commences at 10:00 and is repeated every 2 hours. Participants may opt-out for blood sampling without affecting their participation. The repetition of biomarker assessments allows to evaluate the stability and test-retest reliability of baseline biomarkers as well as refining the optimal testing period during the circadian day. Healthy age- and gender-matched healthy control participants will undergo the identical protocol to establish normative thresholds for driving and neurobehavioral performance. At the end of the extended wakefulness period, participants are given the opportunity to sleep as normal in the lab or being discharged with the possibility to be driven home by taxi. The focus of this study is to use an extended-wakefulness protocol to test driving performance, routine clinical sleep study metrics and the identified candidate biomarkers in a new cohort of OSA patients, and divide them into vulnerable versus resistant groups, based on normal control data cut-offs. We will complete a phase-1 diagnostic test evaluation study to validate the predictive value of candidate biomarkers identified in our discovery study and contrast this with the MWT in differentiating between OSA patients who are vulnerable versus those who are resistant to alertness failure. The focus of this study is to use an extended-wakefulness protocol to test driving performance, routine clinical sleep study metrics and the identified candidate biomarkers in a new cohort of OSA patients, and divide them into vulnerable versus resistant groups, based on normal control data cut-offs. We will complete a phase-1 diagnostic test evaluation study to validate the predictive value of candidate biomarkers identified in our discovery study and contrast this with the MWT in differentiating between OSA patients who are vulnerable versus those who are resistant to alertness failure.