Despite drop out of the more impaired drivers within the Parkinson disease (PD) cohort, returning drivers with PD, who drove like controls without PD at baseline, showed many more driving safety errors than controls after 2 years, a recent study found. Drivers with PD (n=67) and healthy controls (n=110) drove a standardized route in an instrumented vehicle and were invited to return 2 years later. A professional driving expert reviewed drive data and videos to score safety errors and found:

• At baseline, drivers with PD performed worse on visual, cognitive, and motor tests, and committed more road safety errors compared to controls.
• At baseline, returnees with PD made fewer errors than non-returnees with PD and performed similar to control returnees.
• Baseline global cognitive performance of returnees with PD was better than that of non-returnees with PD, but worse than for control returnees.
• After 2 years, returnees with PD showed greater cognitive decline and larger increase in error counts than control returnees.