https://www.sciencedaily.com/releases/2018/07/180726161023.htm

In order to explore AD and healthy older drivers, a video recording device was placed behind the rear-view mirror of each driver's vehicle. Twenty patients with early-stage Alzheimer's disease and twenty-one healthy older adults were included in the study. Two expert psychologists assessed driving performance using a specially designed Naturalistic Driving Assessment Scale (NaDAS), paying particular attention to self-regulation behavior (capacity to adapt driving speed, respect safe distances, change lanes correctly, and appropriately anticipate or plan actions. All critical safety events (accident, near-accident, incident) were also recorded.

The results showed that self-regulation behavior was poorer in AD patients than in healthy older drivers. Lower self-regulation reflects a reduced capacity to adapt driving speed, ensure safe distances, change lanes, and appropriately anticipate or plan actions. Moreover, AD patients experienced twice as many critical events as healthy older drivers. Several naturalistic driving studies have demonstrated that the number of critical events is associated with accident risk. Interestingly, two thirds of critical events were considered "unaware" events, which means the driver was observed to have no clear reaction during the critical event. AD patients who exhibited the worst self-regulation had the most critical events. This relationship between a high number of critical events and poorer self-regulation behavior has not been demonstrated previously.