Hazard perception, traffic situation overview and reaction time in drivers with early Alzheimer’s disease

In the Netherlands patients with early Alzheimer’s disease (AD) are allowed to drive if their fitness to drive is positively evaluated. The assessment consists of a clinical interview and an on-road examination. Previous research concludes that on-road performance by AD patients could be accurately predicted (92.7 percent) within a clinical setting on the bases of a combination of three assessments: 1) a clinical interview, 2) neuropsychological tests and 3) driving in a driving simulator (Piersma et al., 2016). In the current research at SWOV, the Dutch Institute for Road Safety Research, we examine if this method leads to the same prediction with a new group of AD patients. The neuropsychological tests include a series of reaction time tests, a hazard perception test, the Adaptive Tachistoscopic Traffic Perception Test and a driving simulator test drive. It is hypothesized that early AD patients react slower, have more difficulty overseeing traffic situations and perceiving possible hazards while driving. Results confirm the hypothesis in the sense that, compared to healthy controls, AD patients have a slower cognitive/motoric RT to visual/auditory/combined stimuli, need more time to react to traffic situations, have a harder time getting an overview of traffic situations and brake later in response to a driver that suddenly swerves onto the road in a simulated drive. In future research the reduction of hazard perception ability, the ability to get an overview of traffic situations and cognitive/motoric RT at which an AD driver can still safely participate in traffic and also the effectiveness of coping strategies could be investigated.