Drivers with Parkinson's disease: are the symptoms of PD associated with restricted driving practices?

This study examined whether symptoms (motor, cognitive, vision, sleepiness, depression) of Parkinson's disease (PD) were associated with restricted driving practices. To quantify driving practices, electronic devices were installed in the vehicles of 27 drivers with PD (78 % men; M = 71.6, SD = 6.6; Unified Parkinson's Disease Rating Scale (UPDRS) motor score M = 30.1, SD = 8.6; disease duration M = 3.9, SD = 2.8 years) and 20 controls (80 % men; M = 70.6, SD = 7.9) for 2 weeks. Participants completed measures of sleepiness, depression, quality of life, and assessments of motor, cognitive and visual functions. The PD group had significantly slower brake response times (p < 0.05), poorer cognitive and quality of life scores (p < 0.01) and greater depression (p < 0.05) compared to controls. Slower reaction time was significantly related to reduced driving; specifically, fewer trips (r = -0.46; p < 0.05), distance (r = -0.54, p < 0.01) and duration at night (r = -0.58, p < 0.01). Better cognitive scores were associated with driving less often in difficult situations such as bad weather and rush hour (p < 0.05), as well as reduced speed on city streets, but only for the control group. While most drivers with PD rated their overall health as good or excellent, the five PD drivers who rated their health more poorly had significantly worse clinical symptoms (UPDRS motor scores, contrast sensitivity, depression, brake response time) and more restricted driving patterns. These findings show that drivers with PD who perceive their health poorly have greater symptomatology and were more likely to restrict their driving, possibly due to noticeable declines in multiple driving-related abilities.