| Little is known about the specific cognitive impairments that may be the cause of the reported increased crash rate in individuals with early dementia. Though, it is widely accepted that attention, visuospatial and perceptual abilities are central in being able to operate a vehicle safely. This study had three objectives. The first was to clarify the neuropsychological profile, with an emphasis on attention, visuospatial and perceptual abilities, of individuals with early dementia with Lewy bodies (DLB), the next was to examine the driving performances of two groups of individuals with early dementia (i.e., early Alzheimer's disease, AD, and early DLB) and the last was to examine the degree of association between neuropsychological impairments and driving impairments in hopes of predicting poor driving outcomes. Fifty-six participants were recruited from three groups; 20 individuals diagnosed with early AD, 15 individuals diagnosed with early DLB and 21 healthy age-matched controls. All participants were administered the following neuropsychological tests: the Mini-Mental Status Exam (MMSE), the Dementia Rating Scale (DRS-2), the Boston Naming Test (BNT), the Test of Everyday Attention (TEA), the Visual Object and Space Perception Test (VOSP) and the Useful Field of View (UFOV). Additionally, a simulated driving task was completed, with data being collected through primary measures recorded by the simulator as well as an experimenter based driving assessment using a demerit-point test. Results indicated that individuals with early DLB were found to be most impaired in their visuospatial abilities, selective and divided attention abilities, and were found to have significant cognitive fluctuations. Driving performances confirmed that drivers with early dementia were at greater risk for motor vehicle collisions (MVC) and they were found to commit a significant number of driving errors during the driving simulation. Finally, this study was able to demonstrate that in drivers with early AD, attentional impairments were the strongest predictors of driving impairment, whereas in drivers with early DLB, visuospatial impairments were indicative of driving impairment. |
