Introduction Some patients with OSAS are at higher risk of being involved in road traffic accidents. No objective tests have been shown to predict reliably whether an individual is safe to drive or not and there is significant variation in the advice given by the clinicians. Using continuously measured variables in an advanced PC-based driving simulator the at risk patients can be identified with a high degree of accuracy.
We have investigated whether this finding is repeatable. Individuals may “raise their game” if they know that their licence is at stake. We have therefore also investigated the effect of an incentive on the test.
Methods 150 untreated OSAS patients (males-131) were randomised to either the repeatability (n = 50) or incentive arm (n = 100). All performed a simulator run, after initial acclimatisation. In the repeatability arm, patients performed the simulator run on two separate occasions with no knowledge of the results. In the incentive arm, patients performed the simulator run on two separate occasions but just prior to the second run were told about their performance and offered a prize if they could improve their performance by 10%.
SDLP in epoch 3 and “veer” reaction time (Veer-RT) were the co-primary outcome variables. Classification of patients into "pass", "fail" and "indeterminate" were the secondary outcome variables. Results were analysed using paired and unpaired T tests with the level of significance set at p < 0.05.
Results 137 patients (repeatability arm-48, incentive arm-89) completed the trial. The median duration between the two simulator runs was 13 days (range, 5–55). SDLP in epoch 3 and Veer-RT were repeatable (P- 0.54, Δ SDLP- 0.01 and P- 0.37, Δ Veer-RT- 0.13) respectively. There was no effect of an incentive on SDLP in epoch 3 (P-0.18) and Veer-RT (P-0.57). There was no difference in the simulator outcome between the two runs [pass (P- 0.70), indeterminate (0.06), fail (P- 0.16)].
Conclusions SDLP and Veer-RT are consistent between runs on the MiniUoLDS and this is not affected by a simple incentive. Advanced office PC based simulators may be helpful when advising patients with OSAS about driving.