Effect of subthalamic nucleus deep brain stimulation on driving in Parkinson disease

Objective: To examine the influence of subthalamic nucleus (STN) deep brain stimulation (DBS) on driving in patients with Parkinson disease (PD). Methods: Using a driving simulator setup proven to reflect on-road driving, 2 main analyses were performed: 1) comparison of driving performance among 23 patients with deep brain surgery (DBS patients), 21 patients without surgery (no-DBS patients), and 21 controls; and 2) analysis of the effect of stimulation vs levodopa on driving performance. To this end, 3 tests were run in the medicated DBS patient cohort, with 3 different conditions: “stimulation on” (STIM) (equated to daily treatment), “stimulation off” (OFF), and “stimulation off/levodopa” (LD) (dosage aimed at maintaining motor status). Differences in driving times and errors among conditions were analyzed. Results: Age and cognitive deficits influenced driving performance negatively. The no-DBS patient group performed worse in driving time and driving errors than controls. DBS patients drove slower than controls and no-DBS patients. Driving safety was comparable to controls but higher than in no-DBS patients. Within the DBS patient group, driving was more accurate with STIM than with LD, although motor effects did not differ. Driving with STIM, but not with LD, was superior to driving in the OFF condition. Conclusion: DBS of the STN seems to have a beneficial effect on driving ability in patients with PD, potentially because of nonmotor driving-relevant aspects. Our data suggest that driving permission for DBS-treated patients with PD should not be handled more restrictively than permissions for patients with PD in general. Classification of evidence: This study provides Class IV evidence that STN-DBS in patients with PD is associated with a reduction in driving errors and improvements in driving accuracy in driving simulations.