Parkinson's disease and driving ability.

There is no guidance available for clinicians who have to decide on the fitness to drive of patients who have Parkinson's disease (PD). A computerised driving simulator was used to examine the effect of PD on driving ability. Ten drivers with idiopathic PD were tested as well as 10 age and sex-matched healthy drivers and four PD drivers who were no longer driving. Both the simulated driving reaction time and the accuracy of steering were significantly impaired in the PD group compared with the controls. Both of these measures correlated significantly with the severity of PD as measured on Webster's rating scale. Caution may be needed if the findings of simulated tests are to be extrapolated to real driving. However, our findings show that the severity of disability in PD as measured by Webster's rating scale may assist in assessing the fitness of a PD patient to drive.