The automobile, for better or for worse, has become a crucial ally in our day-today functioning. Even older individuals who have moved beyond the demands of work or shuttling children are adamant about continuing to drive, if only to the local grocery store or senior centre. When asked, they will say they want the freedom to come and go as they please, the independence from reliance on relatives or friends. Driving does enhance autonomy but also, unfortunately, poses safety risks. Manipulating this ever more sophisticated piece of machinery in a fastpaced environment requires quick reactions and the ability to process multiple stimuli simultaneously. Unfortunately, these critical cognitive skills become compromised with ageing: reaction time is slowed and it is more difficult to focus on more than one thing at a time. Elderly drivers are at higher risk than all other age groups for involvement in motor vehicle accidents (MVA) on a per-mile basis, consequent to age-related changes in cognitive, sensory, and motor functions as well as increased medical complications. When an older person suffers dementia, there are disturbances in a broad range of cognitive functions; and a deterioration in previously learned abilities, especially complex tasks. Unfortunately dementia, even in early stages, can also affect insight and judgement so that these cognitive impairments are not recognised and appropriate modifications are not self instituted. While most investigators and professionals agree that persons with advanced dementia are at increased risk for hazardous driving, there is no consensus on whether or when individuals with mild or questionable dementia should have restrictions on driving. This latter group presents a major challenge to family members and professionals. Deficits are mild and perhaps inconsistent, and the primary care physician cannot easily differentiate an early dementing process from what might be normal ageing. The neuropsychologist, in collaboration with other healthcare professionals, is in a unique position to assist in the diagnosis of early cognitive decline, to determine the severity of neurocognitive and neurobehavioral dysfunction, to track progression of impairment over time, to identify patterns of cognitive strengths and weaknesses that may predict functional impairment, and to assist individuals and families in negotiating the delicate balance between safety and autonomy, particularly in regard to driving. Despite the well-established value of neuropsychological assessment in the diagnosis of early cognitive decline, the utility of neuropsychological measures in the determination of driving competence has not been researched adequately. Surprisingly few studies have examined the role of neuropsychological functioning as an early indicator of potentially unsafe driving. Findings from the limited studies that have examined the relationship between cognitive factors and driving ability are inconsistent, likely reflecting the varied mental status and neuropsychological instruments utilised, the differing criterion measures of driving competence, and the small sample sizes and heterogeneity of patient populations. Studies examining the relationship between Mini Mental Status Examination (MMSE) scores and driving ability have been equivocal, as might be expected using a single, broad test that has been shown to be insensitive to early-stage cognitive loss. As such, Duchek and colleagues suggested that cognitive screening measures should be used to identify those individuals at risk for driving impairment and in need of more thorough evaluation of the specific skills and processes that influence driving performance. Investigators who employed specific neuropsychological tests have reported inconsistent results. The majority of these studies either restricted their focus to measures of memory, language, and visuoperception, while neglecting to examine the role of specific executive functions, or they utilised executive measures that may not detect the specific type of dysfunction that affects driving ability. Executive functions such as planning, problem-solving, response initiation/inhibition, and sustained, selective and divided attention have intuitive appeal as factors related to safe driving. However, they have not been explored adequately to date. One notable exception is the research on visual attention. (A)
Abstract