Study 1: Patients with Parkinson's disease (PD) patients are difficult to engage in driving due to an impaired motor function and decreased attention capabilities. In our study, driving simulator (Safety Master NT-932) was applied to evaluate the driving ability of 'On' state PD patients (n=42) in comparison with neurological signs. We studied the correlations between the total Unified Parkinson's disease Scale (UPDRS) score, the UPDRS part III score, braking reaction time, steering wheel errors and total scores for driving safety test results. The number of steering wheel errors was increased in association with higher total UPDRS, UPDRS part III and postural instability sub-scores. However, the braking reaction time showed no correlation with the scores. The UPDRS alone is not sufficient to decide whether PD patients should be allowed to drive. Determining the driving ability using a driving simulator might be useful as an adjunct to UPDRS scores in the assessment of PD drivers.
Study 2: Pregabalin, a novel agent in treating partial epilepsy and peripheral neuropathic and central pain, was studied for its effect on driving performance in healthy volunteers. A double-blind, parallel-group, placebo-controlled study was conducted in 16 healthy male subjects receiving an oral dose of pregabalin 75 mg or placebo, and a second dose 12 hours after. The driving simulator was used to test the braking reaction time and steering-wheel technique before and after taking the pregabalin or placebo. The effect of training during the driving test on the driving performance of each group was also evaluated. There were no significant differences in driving performance between the pregabalin and the placebo groups. The pregabalin group also showed no improvement in steering-wheel skills with training, whereas the placebo group showed a significant (p<0.05) improvement with training. Pregabalin did not impair the driving performance but mildly reduced the training effects of driving experiments. Although pregabalin caused sleepiness, it had no severe effect on driving ability after a second dose of 75 mg after the initial introduction of pregabalin.