Predictors of driving cessation in mild-to-moderate dementia

Abstract

A landmark study of the epidemiology of dementia, the Canadian Study on Health and Aging (CSHA) determined that in 1992, some 316 500 Canadians over the age of 65 years (1 in 13) had dementia, with the risk of the disease doubling for every 5 years of age after 65.1,2 With the increasing mean age of our population, it is estimated that 500 000 Canadians will have dementia by 2021, and 750 000 by 2031.3 Although incidents involving drivers affected by dementia frequently make the headlines in the lay press, there is surprisingly little data on the factors in dementia that may be associated with driving cessation. In a cross-sectional study of community-dwelling subjects, Foley and colleagues 4 found that 46% of those whose dementia was rated as questionable (i.e., with a Clinical Dementia Rating 5 [CDR] of 0.5) and 22%, as mild (CDR 1) were still driving. Indeed, Duchek and associates 6 found that of patients who passed an on-road test at baseline, only about 20% of those with questionable dementia and none of those with mild dementia passed another road test 2 years later. In a retrospective study of 430 patients at a memory clinic, age, an urban dwellingplace, level of cognitive function and relative ability to perform the activities of daily living were found to be predictive of driving cessation.7 Similarly, in a small prospective study of 53 patients with dementia, age and Mini-Mental State Examination (MMSE) 8 score predicted driving cessation over the next 2-3 years.9 Determination of the factors associated with driving cessation is important, given the well-documented association between the risk of being involved in a motorvehicle collision and the severity and duration of the dementia. 10Clinical practice guidelines have not been consistently helpful in providing physicians with guidance related to driving and dementia. For example, although the conclusions of the Canadian Consensus Conference on Dementia 3 emphasized the need to assess patients with dementia for fitness to drive and provided suggestions for factors requiring evaluation (e.g., cognition, function, medical status, medication review), there did not provide specific guidelines for how to determine when driving cessation was necessary. In contrast, the American Academy of Neurology practice parameter for risk of driving in cases of Alzheimer's disease 11 provides much clearer recommendations for driving cessation, based on CDRs. Unfortunately, most primary care physicians are unfamiliar with CDRs and may have difficulty using athe ratings in everyday practice. The guide published by the Canadian Medical Association 12 quotes the National Safety Code, which has suggested that patients whose MMSE score is less than 24 are ineligible to hold a driver's license unless they have undergone a complete neurologic assessment. Unfortu- Predictors of driving cessation in mild-to-moderate dementiaBackground: Although physicians in most provinces are mandated to report patients whose driving ability is impaired by illness, little is known about dementi...

Practice Parameter update: Evaluation and management of driving risk in dementia

“…In patients with mild to moderate dementia (mean MMSE ϭ 21.9), a Class II study 31 reported that agitation and aggression were predictive of a refusal to discontinue driving (hazard ratio for driving cessation ϭ 0.54, 95% CI 0.32-0.90). In a Class III study of all-aged drivers (downgraded one evidence class), 32 deliberate violations of driving laws, across all ages, correlated with future crashes (␤ ϭ Ϫ0.12, p Ͻ 0.001).…”

The relationship between cognitive performance, perceptions of driving comfort and abilities, and self-reported driving restrictions among healthy older drivers

“…Insight into one's driving capabilities may play a role in the decision making regarding driving cessation or restriction. Although prior studies have shown that driver perceptions are related to self-regulatory practices in healthy older drivers Myers et al, 2011), those with cognitive impairment may lack the capacity to recognize their driving limitations and restrict their driving practices to compensate appropriately (Herrmann et al, 2006;Rapoport et al, 2007).…”

Psychological and Cognitive Aspects of Ageing: The Importance of Driving on Senior Living

“…Although a large number of studies suggest that individuals with moderate to severe dementia are unable to drive, there is no clear definition regarding the onset of dementia [62][63][64], relatively little is known about the driving performance of senior drivers with MCI [51,65], few studies demonstrate the relationship between MCI and driving performance [65][66][67][68][69][70][71][72][73], and there is no full consensus on the measurement of impairment in driving in seniors with MCI or whether they consequently have a higher risk of accidents compared to healthy people of the same age [51,64]. The available research from driving simulators and road studies suggests that drivers with MCI have prominent difficulties with navigation and decisions.…”