Driving Performance and Its Correlation with Neuropsychological Tests in Senior Drivers with Cognitive Impairment in Japan.

BACKGROUND With the rapid aging of the population, the issue of driving by dementia patients has been causing increasing concern worldwide. OBJECTIVE To investigate the driving difficulties faced by senior drivers with cognitive impairment and identify the specific neuropsychological tests that can reflect specific domains of driving maneuvers. METHODS Senior drivers with cognitive impairment were investigated. Neuropsychological tests and a questionnaire on demographic and driving characteristics were administered. Driving simulator tests were used to quantify participants' driving errors in various domains of driving. RESULTS Of the 47 participants, 23 current drivers, though they had better cognitive functions than 24 retired drivers, were found to have impaired driving performance in the domains of Reaction, Starting and stopping, Signaling, and Overall (wayfinding and accidents). The parameters of Reaction were significantly related to the diagnosis, and the scores of MMSE, TMT-A, and TMT-B. As regards details of the driving errors, "Sudden braking" was associated with the scores of MMSE (ρ= -0.707, p < 0.01), BDT (ρ= -0.560, p < 0.05), and ADAS (ρ= 0.758, p < 0.01), "Forgetting to use turn signals" with the TMT-B score (ρ= 0.608, p < 0.05), "Centerline crossings" with the scores of MMSE (ρ= -0.582, p < 0.05) and ADAS (ρ= 0.538, p < 0.05), and "Going the wrong way" was correlated with the score of CDT (ρ= -0.624, p < 0.01). CONCLUSION Different neuropsychological factors serve as predictors of different specific driving maneuvers segmented from driving performance.