Driving simulation with EEG monitoring in normal and obstructive sleep apnea patients

Study Objectives: To measure simulated driving performance in obstructive s leep apnea patients and its relationship with EEG defined attention lapses. Design: Prospective, mixed design comparing apnea patients and control subj ects over a 60-minute driving simulation task while continuously recording both driving performance and EEG measures. Setting: Sleep disorders center Participants: 15 polysomnographically diagnosed obstructive sleep apnea pat ients (mean age 42 +/- 6 yrs.) and 15 healthy volunteers (mean age 38 +/- 6 yrs.). Interventions: NA Measurements and Results: A computer based driving simulator recorded lane position variability, speed variability, steering rate variability, and cra sh frequency. The frequency and duration of EEG-defined attention lapses we re also measured. The results demonstrated that the apnea group had signifi cantly greater variability in lane position, steering rate, and speed than the control group. The apnea group also had more crashes. In addition, the apnea group had more EEG-defined attention lapses of longer duration. Excep t for speed and steering rate variability, these differences increased over the 60-minute task. Measures of lane position variability and crash freque ncy had a significant positive correlation with attention lapse frequency a nd duration. Conclusions: The driving simulation task unmasked and quantified marked per formance impairments in the sleep apnea group that increased over time, The poor performance appeared related to the EEG-defined attention lapses. Lan e position variability appeared to be the most sensitive measure for assess ing and quantifying impairment. This study suggests that poorer driving per formance and crashes are not entirely due to overt sleep, but inattention d ue to sleepiness.