Search

Patients with obstructive sleep apnoea syndrome (OSAS) have an increased car accident rate. Investigations on accident frequency are based on case history, insurance reports and driving simulator studies. The present study combines neuropsychological testing of different attention aspects engaged in driving a car and driving simulation to evaluate a suitable instrument for assessing therapeutic effects of continuous positive airway pressure (CPAP). Driving simulator investigation and neuropsychological testing of alertness, vigilance and divided attention were performed in 31 patients with polysomnographically confirmed OSAS (apnoea-hypopnoea index 24.8+/-21.5.h(-1)) before, and 2 and 42 days after initiation of CPAP. Divided attention and alertness improved significantly during CPAP, whereas vigilance remained unchanged. However, accident frequency (OSAS before therapy: 2.7+/-2.0; 2 days after CPAP: 1.5+/-1.4; 42 days after CPAP: 0.9+/-1.3) and frequency of concentration faults (OSAS before therapy: 12.4+/-5.1; 2 days after CPAP: 6.5+/-3.9; 42 days after CPAP: 4.9+/-3.3) decreased in the simulated driving situation after 2 and 42 days of therapy. There was no relation between accident frequency, concentration faults and daytime sleepiness, as measured by the Epworth Sleepiness Scale, and polysomnographic or neuropsychological findings, respectively. In conclusion, the present results suggest that driving simulation is a possible benchmark parameter of driving performance in obstructive sleep apnoea syndrome patients.

Abstract. Patients with obstructive sleep apnea syndrome (OSAS) have an accident rate between two and seven times higher than normals. Investigations on accident frequency are based on case history, insurancy reports, and driving simulator investigations. The present controlled study was planned to test whether an increased accident risk could be demonstrated in patients with OSAS before and on CPAP (continuous positive airway pressure)-therapy using the driving simulator C.A.R. Driving simulator performance was investigated in 31 patients with polysomnographically confirmed OSAS (apnea-hypopnea-index 24.8 +/- 21.5/h) before, 2 and 42 days after initiation of CPAP and was compared to 10 healthy controls in whom OSAS was excluded by polysomnography. Driving simulator performance was significantly worse in OSAS as compared to normals especially in terms of accident frequency (OSAS: 2.7 +/- 2.0, controls: 1.3 +/- 1.5, p < 0.05) and concentration faults (OSAS: 12.4 +/- 5.1, controls: 7.1 +/- 3.2, p < 0.01). On CPAP accident frequency (OSAS before therapy: 12.4 +/- 5.1, 2 days CPAP: 1.5 +/- 1.4, p < 0.01; 42 days CPAP: 0.9 +/- 1.3, p < 0.001) and frequency of concentration faults (OSAS before therapy: 12.4 +/- 5.1, 2 days CPAP: 6.5 +/- 3.9, p < 0.001; 42 days CPAP: 4.9 +/- 3.3, p < 0.001) could be lowered significantly both in the short and medium term of therapy. The driving simulator C.A.R. is an adequate tool for the evaluation of an increased accident risk in OSAS-patients and demonstrates the efficiency of CPAP-therapy.