Reactions at intersections of drivers with Alzheimer’s disease: the association between neuropsychological assessment and driving errors in a driving simulator

Driving maneuvers that require increased cognitive load may be more systematically impaired than global driving ability in drivers with Alzheimer’s disease (AD). Because navigating an intersection is a demanding on road event, errors seen in this context might be more sensitive and indicative of the extent of cognitive changes seen in drivers with AD. The objective of this study is to explore the associations between neuropsychological test outcomes and driving simulator performance at intersections. Seventeen English speaking older adults with a diagnosis of mild AD were recruited from a hospital-based memory clinic. Twenty-one neurologically healthy control participants were also recruited as age-matched control participants. Neuropsychological measures were administered to all participants prior to completing two simulated driving scenarios. Errors at intersections were examined using a systematic scoring system to classify all errors made during preparation, execution, or at recovery. In contrast to our previously published data, one global measure of cognition (the Mini Mental State Exam; MMSE) was significantly associated with driver errors, specifically while coping with intersections. Errors of preparation and execution at intersections were significantly associated with MMSE scores for AD drivers. This suggests that the more fine-grained evaluation of driver behaviour at intersections, relative to overall driving simulator performance, may provide further insight into the cognitive challenges that drivers with AD experience. The systematic approach to analysing intersections presented here allows for greater sensitivity in identifying important differences in driver behaviour. This evaluation scheme provides a novel approach to evaluate driver behaviour and allows for the calculation of the frequency of errors according to type and when they occur in the intersection. Further, insofar as we are concerned with fitness to drive, the cognitive challenges experienced by AD drivers may be better captured by this highly specific approach when compared to other variables of overall driving performance.