Impaired driving simulation in patients with Periodic Limb Movement Disorder and patients with Obstructive Sleep Apnea Syndrome.

BACKGROUND

Excessive daytime sleepiness (EDS) is considered to be responsible for increased collision rate and impaired driving simulator performance in Obstructive Sleep Apnea Syndrome (OSAS) patients. Periodic Limb Movement Disorder (PLMD) patients also frequently report EDS and may also have impaired driving capacities.

METHODS

PLMD patients (n=16), OSAS patients (n=18), and controls (n=16) performed a monotonous 25-min driving simulation task. Parameters for driving capacity were the slope of the standard deviation of the lane position, lapses of attention (LOA), and structural deviations. The severity of sleep disruption and the degree of subjective sleepiness were measured.

RESULTS

Slope and LOA were significantly higher in patients than controls, pointing to a decreased driving performance. At start patients and controls had similar driving capacity. The PLMD and OSAS groups did not differ on any scale or simulation performance, although OSAS patients generally performed worse. Subjective sleepiness was higher in patients than controls, and correlated positively with driving simulator parameters. Severity of the disorder and performance were uncorrelated.

CONCLUSION

PLMD and OSAS patients showed impaired performance in a simulated monotonous driving task. At start, patients and controls performed similarly, but patient performance decreased clearly with time, suggesting that decreased vigilance as a result of disturbed sleep is an important component of deteriorated simulated and, possibly, real driving performance.