What contributes to driving ability in Parkinson's disease

Purpose. To determine the most significant clinical predictors that influence driving ability in Parkinson disease (PD). Methods. National-multi-centre, cross-sectional study covering PD outpatients. Clinical assessment was based on the following questionnaires: cognition (SCOPA-Cog); motor impairment and disabilities (SCOPA motor); depression/anxiety; sleep (SCOPA-Sleep); psychosis and severity/global impairment (HY and CISI-PD). Driving status data was obtained using a standardized questionnaire. Comparisons between drivers and ex-drivers were calculated using χ2 and Student t-tests as appropriate. Multi-variate logistic regression analysis was performed to identify independent driving ability clinical predictors. Results. Compared with the drivers, the ex-drivers were older (p = 0.00005), had longer disease duration (p = 0.03), had more overall cognitive dysfunction (p = 0.004) and had greater motor impairment, as measured by the CISI (p = 0.02), HY stage (p = 0.034) and by the SCOPA-motor scale (p = 0.002) and difficulty in activities of daily life (p = 0.002). In the regression model analysis, aging and ADL impairment were the principal clinical predictors that differentiated drivers from ex-drivers. Conclusions. Although overall driving impairment in PD is associated with advancing disease severity, driving ability seems to be more strongly influenced by age and ADL impairment. Multi-disciplinary teams are required to assess driving ability in patients with PD and develop rehabilitation measures for safer driving.