How to investigate fitness to drive in patients with Alzheimer’s dementia

Background: In early stages of dementia, some patients are still fit to drive, but others are not. Patients and their family members seek for advice from their physicians. The gold standard to determine fitness to drive is a test ride on the road, but it remains difficult to decide which patients should be advised to do such a time and effort demanding on-road driving assessment and which not, as sensitive alternative instruments are lacking. Objective: The goal of this study is to develop a validated off-road fitness-to-drive test battery for older drivers with dementia. Methods: Patients with Alzheimer’s disease (n=100) performed a fitness-to-drive test battery consisting of interviews with the patient and an informant, various neuropsychological tests and rides in a driving simulator. All participants also completed a test ride on the road. Results: The validity of the off-road fitness-to-drive test battery was examined, in particular regarding its accuracy in predicting on-road driving performance. With information from the interviews only, 72,3% of the patients were classified correctly as fit or unfit to drive. When using neuropsychological tests or driving simulator rides, respectively 81,6% and 78,9% of the patients were classified correctly. A combination of the predictions based on the interviews, neuropsychological tests and driving simulator rides resulted in a correct classification in 88,5% of the cases. Conclusion: Interviews with patients with dementia and their informants have predictive value for fitness to drive. Neuropsychological tests and driving simulator rides both improve the accuracy of the prediction significantly. Three tests of the test battery were most predictive: tests for motor speed, hazard perception, and traffic theory knowledge. The test battery will serve both patients affected as well as those involved in the decision making process