Driving and dementia: a review of the literature

Mild cognitive impairment: safe to drive?

Driving is an important aspect of daily living and for many older people provides autonomy and psycho-social benefits. Cognitive impairment has been found to impact driving skills at the level of dementia, however, uncertainty remains around the impact of a diagnosis of the pre-dementia condition mild cognitive impairment. Current official guidelines are unclear, and assessment of fitness to drive can be problematical. This editorial examines current official guidance available to the clinician and problems with existing assessment as well as the current position of research specifically into MCI and driving, and considers future direction for research in this field.

Development and pilot testing of a decision aid for drivers with dementia

BACKGROUND

An increasing number of older adults drive automobiles. Given that the prevalence of dementia is rising, it is necessary to address the issue of driving retirement. The purpose of this study is to evaluate how a self-administered decision aid contributed to decision making about driving retirement by individuals living with dementia. The primary outcome measure in this study was decisional conflict. Knowledge, decision, satisfaction with decision, booklet use and booklet acceptability were the secondary outcome measures.

METHODS

A mixed methods approach was adopted. Drivers with dementia were recruited from an Aged Care clinic and a Primary Care center in NSW, Australia. Telephone surveys were conducted before and after participants read the decision aid.

RESULTS

Twelve participants were recruited (mean age 75, SD 6.7). The primary outcome measure, decisional conflict, improved following use of the decision aid. Most participants felt that the decision aid: (i) was balanced; (ii) presented information well; and (iii) helped them decide about driving. In addition, mean knowledge scores improved after booklet use.

CONCLUSIONS

This decision aid shows promise as an acceptable, useful and low-cost tool for drivers with dementia. A self-administered decision aid can be used to assist individuals with dementia decide about driving retirement. A randomized controlled trial is underway to evaluate the effectiveness of the tool.

Driving, dementia and Australian physicians: primum non nocere?

Older Australians are increasingly reliant on automobiles as their sole form of transport. As our population is ageing and the prevalence of dementia is increasing, it is anticipated that the number of drivers with dementia will rise over time. Much of the literature relating to driving and dementia focuses on safety rather than mobility. The objective of this paper is to highlight several topical ethical issues that pertain to Australian drivers with dementia. It is recommended that future research, policy and practice should centre on the crucial mobility and transport needs of our senior citizens.

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

The objective of the present study was to examine the relationship between cognitive performance, driver perceptions and self-reported driving restrictions. A cross-sectional analysis was conducted on baseline data from Candrive II, a five-year prospective cohort study of 928 older drivers aged 70-94 years from seven cities. Cognitive performance was assessed using the Montreal Cognitive Assessment (MoCA) as well as the Trail Making Test, parts A and B. Driver perceptions were assessed using the Day and Night Driving Comfort Scales and the Perceived Driving Abilities scale, while driving practices were captured by the Situational Driving Frequency and Avoidance scales, as well as the Driving Habits and Intentions Questionnaire. The baseline data indicates this cohort is largely a cognitively intact group. Univariate regression analysis showed that longer Trails A and B completion times were significantly, but only modestly associated with reduced driving frequency and perceived driving abilities and comfort, as well as a significant tendency to avoid more difficult driving situations (all p<.05). Most of these associations persisted after adjusting for age and sex, as well as indicators of health, vision, mood and physical functioning. Exceptions were Trails A and B completion times and situational driving frequency, as well as time to complete Trails B and current driving restrictions. After adjusting for the confounding factors, the total MoCA score was not associated with any of the driving measure scores while the number of errors on Trails A was significantly associated only with situational driving frequency and number of errors on Trails B was significantly associated only with situational driving avoidance. Prospective follow-up will permit examination of whether baseline cognition or changes in cognition are associated with changes in driver perceptions, actual driving restrictions and on-road driving outcomes (e.g., crashes, violations) over time.

Cognitive deficits are associated with poorer simulated driving in older adults with heart failure

BACKGROUND

Cognitive impairment is prevalent in older adults with heart failure (HF) and associated with reduced functional independence. HF patients appear at risk for reduced driving ability, as past work in other medical samples has shown cognitive dysfunction to be an important contributor to driving performance. The current study examined whether cognitive dysfunction was independently associated with reduced driving simulation performance in a sample of HF patients.

METHODS

18 persons with HF (67.72; SD = 8.56 year) completed echocardiogram and a brief neuropsychological test battery assessing global cognitive function, attention/executive function, memory and motor function. All participants then completed the Kent Multidimensional Assessment Driving Simulation (K-MADS), a driving simulator scenario with good psychometric properties.

RESULTS

The sample exhibited an average Mini Mental State Examination (MMSE) score of 27.83 (SD = 2.09). Independent sample t-tests showed that HF patients performed worse than healthy adults on the driving simulation scenario. Finally, partial correlations showed worse attention/executive and motor function were independently associated with poorer driving simulation performance across several indices reflective of driving ability (i.e., centerline crossings, number of collisions, % of time over the speed limit, among others).

CONCLUSION

The current findings showed that reduced cognitive function was associated with poor simulated driving performance in older adults with HF. If replicated using behind-the-wheel testing, HF patients may be at elevated risk for unsafe driving and routine driving evaluations in this population may be warranted.

The impact of cognitive deficit on self-reported car crashes in ultra-octogenarian population: data of an Italian population-based study

OBJECTIVE

To examine the usefulness of specific neurocognitive tests for predicting the crash involvement in ultra-octogenarian population.

METHODS

A total of 800 subjects (mean age 82.4 + 3.1 years) underwent a battery of neuropsychological tests. Global intellectual functioning was assessed using the Mini Mental State Examination, mental flexibility and information processing speed were assessed using the Trail Making Test parts A and B (TMT-A and TMT-B), long-term memory was evaluated with the short story, and visuo-spatial skills were tested with Clock Drawing Test. One year after this evaluation, 343 (43%) participants have been interviewed by a telephone call to know if they were currently driving and if they had a car crash during this period.

RESULTS

Two hundred ninety-seven subjects had their driving license renewed and completed the follow-up 1 year after. Data shows that less than 11% of this group had a car crash during the first year of observation (Crash Involved). Older subjects involved in a car crash showed significant worse performances on TMT-B (TMT-B pathological Crash Involved vs. Noncrash Involved 47% vs. 27%; p = 0.02) and on short story (short story pathological Crash Involved vs. Noncrash Involved 19% vs. 5%; p = 0.02).

CONCLUSIONS

Trail Making test B and short story have been demonstrated to provide a predictive value of driving performance of older people. Therefore, we suggest that a simple and standardized battery of neuropsychological tests, lasting about 30 min and administered by an experienced staff, is a good diagnostic instrument for risk prevention of driving activity of older drivers.

The driving competence of 90-year-old drivers: from a hospital-based driving clinic

OBJECTIVES

To compare the performance on a standardized driving evaluation of a group of oldest old adults (age 90-97) against younger old adults (age 80-87) and examine whether the same cognitive variables and brake reaction time performance were associated with pass-fail status on a road test in both groups. Secondary objectives focused on an examination of the specific driving errors of both groups.

METHODS

This retrospective cohort study was conducted in the setting of a clinical driving evaluation program at an academic medical center in the United States. In this study we examined the performance of 88 participants (27 age 90-97 and 61 age 80-87) who completed comprehensive driving evaluations between 1997 and 2011. The outcome variable was performance on a standardized road test. Measures included the Trail Making Test (TMT), the Mini Mental State Examination (MMSE), and brake reaction time (BRT). An exploratory analysis of the possible predictive value of specific MMSE subtests was also performed.

RESULTS

Results indicate that the oldest old adults (90-97 years old) were at no greater driving risk than were a younger old (80-87 years old) cohort and made similar types and frequency of driving errors. TMT-B time was associated with pass-fail status in both groups. MMSE attention items discriminated between safe and unsafe younger old drivers, and MMSE orientation items were associated with pass-fail status in the oldest old cohort.

CONCLUSION

Drivers age 90 and above were at no greater driving risk than those one decade younger. MMSE orientation questions may be useful to assist in identifying which oldest old drivers could benefit from a comprehensive driving evaluation including an on-road test.

Driving cessation and dementia: results of the prospective registry on dementia in Austria (PRODEM)

OBJECTIVE

To assess the influence of cognitive, functional and behavioral factors, co-morbidities as well as caregiver characteristics on driving cessation in dementia patients.

METHODS

The study cohort consists of those 240 dementia cases of the ongoing prospective registry on dementia in Austria (PRODEM) who were former or current car-drivers (mean age 74.2 (±8.8) years, 39.6% females, 80.8% Alzheimer's disease). Reasons for driving cessation were assessed with the patients' caregivers. Standardized questionnaires were used to evaluate patient- and caregiver characteristics. Cognitive functioning was determined by Mini-Mental State Examination (MMSE), the CERAD neuropsychological test battery and Clinical Dementia Rating (CDR), activities of daily living (ADL) by the Disability Assessment for Dementia, behavior by the Neuropsychiatric Inventory (NPI) and caregiver burden by the Zarit burden scale.

RESULTS

Among subjects who had ceased driving, 136 (93.8%) did so because of "Unacceptable risk" according to caregiver's judgment. Car accidents and revocation of the driving license were responsible in 8 (5.5%) and 1(0.7%) participant, respectively. Female gender (OR 5.057; 95%CI 1.803-14.180; p = 0.002), constructional abilities (OR 0.611; 95%CI 0.445-0.839; p = 0.002) and impairment in Activities of Daily Living (OR 0.941; 95%CI 0.911-0.973; p<0.001) were the only significant and independent associates of driving cessation. In multivariate analysis none of the currently proposed screening tools for assessment of fitness to drive in elderly subjects including the MMSE and CDR were significantly associated with driving cessation.

CONCLUSION

The risk-estimate of caregivers, but not car accidents or revocation of the driving license determines if dementia patients cease driving. Female gender and increasing impairment in constructional abilities and ADL raise the probability for driving cessation. If any of these factors also relates to undesired traffic situations needs to be determined before recommendations for their inclusion into practice parameters for the assessment of driving abilities in the elderly can be derived from our data.

Dual-task effects of simulated lane navigation and story recall in older adults with and without memory impairment

While driving is a complex task, it becomes relatively automatic over time although unfamiliar situations require increased cognitive effort. Much research has examined driving risk in cognitively impaired elders and found little effect. This study assessed whether mildly memory impaired elders made disproportionate errors in driving or story recall, under simultaneous simulated driving and story recall. Forty-six healthy (61% women; mean age = 76.4) and 15 memory impaired (66% women, mean age = 79.4) elders participated. Cognitive status was determined by neuropsychological performance. Results showed that during dual-task conditions, participants stayed in lane more, and recalled stories more poorly, than when they did the tasks separately. Follow-up analysis revealed that verbatim recall, in particular, was reduced while driving for healthy participants. While memory impaired participants performed more poorly than healthy controls on both tasks, cognitive status was not associated with greater dual-task costs when driving and story recall were combined.

Neuropsychological assessment of driving safety risk in older adults with and without neurologic disease

Decline in cognitive abilities can be an important contributor to the driving problems encountered by older adults, and neuropsychological assessment may provide a practical approach to evaluating this aspect of driving safety risk. The purpose of the present study was to evaluate several commonly used neuropsychological tests in the assessment of driving safety risk in older adults with and without neurological disease. A further goal of this study was to identify brief combinations of neuropsychological tests that sample performances in key functional domains and thus could be used to efficiently assess driving safety risk. A total of 345 legally licensed and active drivers over the age of 50, with no neurologic disease (N = 185), probable Alzheimer's disease (N = 40), Parkinson's disease (N = 91), or stroke (N = 29), completed vision testing, a battery of 10 neuropsychological tests, and an 18-mile drive on urban and rural roads in an instrumented vehicle. Performances on all neuropsychological tests were significantly correlated with driving safety errors. Confirmatory factor analysis was used to identify 3 key cognitive domains assessed by the tests (speed of processing, visuospatial abilities, and memory), and several brief batteries consisting of one test from each domain showed moderate corrected correlations with driving performance. These findings are consistent with the notion that driving places demands on multiple cognitive abilities that can be affected by aging and age-related neurological disease, and that neuropsychological assessment may provide a practical off-road window into the functional status of these cognitive systems.

Both texting and eating are associated with impaired simulated driving performance

OBJECTIVE

Distracted driving is a known contributor to traffic accidents, and many states have banned texting while driving. However, little is known about the potential accident risk of other common activities while driving, such as eating. The objective of the current study was to examine the adverse impact of eating/drinking behavior relative to texting and nondistracted behaviors on a simulated driving task.

METHODS

A total of 186 participants were recruited from undergraduate psychology courses over 2 semesters at Kent State University. We utilized the Kent Multidimensional Assessment Driving Simulation (K-MADS) to compare simulated driving performance among participants randomly assigned to texting (N = 45), eating (N = 45), and control (N = 96) conditions. Multivariate analyses of variance (MANOVA) were conducted to examine between-group differences on simulated driving indices.

RESULTS

MANOVA analyses indicated that groups differed in simulated driving performance, F(14, 366) = 7.70, P < .001. Both texting and eating produced impaired driving performance relative to controls, though these behaviors had approximately equal effect. Specifically, both texting and eating groups had more collisions, pedestrian strikes, and center line crossings than controls. In addition, the texting group had more road edge excursions than either eating or control participants and the eating group missed more stop signs than controls.

CONCLUSIONS

These findings suggest that both texting and eating are associated with poorer simulated driving performance. Future work is needed to determine whether these findings generalize to real-world driving and the development of strategies to reduce distracted driving.

Impaired knowledge of driving laws is associated with recommended driving cessation in cognitively impaired older adults

Background/Aims

The present study examined if knowledge of driving laws independently predicts on-the-road driving performance among cognitively impaired older adults.

Methods

The current study consisted of retrospective observational analyses on 55 cognitively impaired older adults (77.9 ± 6.4 years) that completed an on-the-road driving evaluation, a 20-item knowledge test of driving laws, and a brief cognitive test battery.

Results

Logistic regression found poorer performance on the knowledge test was significantly associated with greater likelihood of recommended driving cessation beyond important demographic and cognitive variables (p < 0.05).

Conclusion

Cognitively impaired patients’ ability to drive may be related to their knowledge regarding common driving laws, in addition to their current level of cognitive functioning.

Neuropsychological assessment of fitness to drive following acquired cognitive impairment

PRIMARY OBJECTIVE

The study evaluated a neuropsychological assessment battery used to assess fitness to drive in cognitively impaired individuals and hypothesized that the battery would be associated with on-road outcome measures. A secondary aim was to explore the relationships between individual neuropsychological tests and driving performance.

RESEARCH DESIGN

The study used a cross-sectional design in which a sample of individuals with various types of cognitive impairment completed the test battery and an on-road driving test.

METHODS AND PROCEDURES

Performance on the test battery was compared to on-road driving performance in 104 individuals with acquired cognitive impairment.

MAIN OUTCOMES AND RESULTS

The battery had 73% sensitivity and 76% specificity in terms of agreement with the 'pass/fail' classification of the on-road driving test. Scores on the battery accounted for 18% of the variance in the total number of corrective interventions performed by a driving instructor during the on-road test. Most tests correlated significantly with driving test outcomes. While one test, the Rey Complex Figure Test, emerged as an independent predictor of driving performance in multiple regression analyses, the variance explained by this single test was small.

CONCLUSIONS

The results provide support for the use of a battery approach to assess fitness to drive.

How does dementia affect driving in older patients?

Driving is a complex activity that always becomes impaired at some point in older adults with degenerative dementia. Over time, disruption of the visual processing circuits of the brain that link the occipital and prefrontal regions, particularly in the right hemisphere, leads to increasing degrees of driving impairment that ultimately preclude safe driving. Neuropsychological tests of visuospatial ability, executive function and attention that tap into the integrity of these brain regions provide the clinician with important information regarding the need for a formal determination of driving competence. Enhancement of cognitive function in these domains through anti-dementia therapy and exercise may partially mitigate risk; however, all drivers with dementia must ultimately retire from driving when dementia becomes moderately severe, and often in earlier stages of the illness. Future efforts to improve screening tests for hazardous driving and to develop interventions to help prolong the time that drivers with mild dementia can continue to drive safely are needed for our increasingly aged and mobile population.

Cognitive impairment and driving: A review of the literature

Although some drivers with mild dementia may continue to drive after the condition has been diagnosed, the ability to drive a motor vehicle safely is eventually lost as the disease progresses. Clinicians involved in dementia care are often asked to make an assessment on whether a patient is fit to drive, even though they often lack basic knowledge and formal training in this area. The purpose of this review was to identify the factors that may differentiate safe from unsafe drivers with cognitive impairment and to discuss management strategies. Isolated information about staging measures or particular cognitive tests was found to be insufficient for decision making. Driving fitness counseling for patients with cognitive impairment requires a solid knowledge base, comprehensive assessment and thoughtful communication.

Predictors of driving safety in early Alzheimer disease

OBJECTIVE

To measure the association of cognition, visual perception, and motor function with driving safety in Alzheimer disease (AD).

METHODS

Forty drivers with probable early AD (mean Mini-Mental State Examination score 26.5) and 115 elderly drivers without neurologic disease underwent a battery of cognitive, visual, and motor tests, and drove a standardized 35-mile route in urban and rural settings in an instrumented vehicle. A composite cognitive score (COGSTAT) was calculated for each subject based on eight neuropsychological tests. Driving safety errors were noted and classified by a driving expert based on video review.

RESULTS

Drivers with AD committed an average of 42.0 safety errors/drive (SD = 12.8), compared to an average of 33.2 (SD = 12.2) for drivers without AD (p < 0.0001); the most common errors were lane violations. Increased age was predictive of errors, with a mean of 2.3 more errors per drive observed for each 5-year age increment. After adjustment for age and gender, COGSTAT was a significant predictor of safety errors in subjects with AD, with a 4.1 increase in safety errors observed for a 1 SD decrease in cognitive function. Significant increases in safety errors were also found in subjects with AD with poorer scores on Benton Visual Retention Test, Complex Figure Test-Copy, Trail Making Subtest-A, and the Functional Reach Test.

CONCLUSION

Drivers with Alzheimer disease (AD) exhibit a range of performance on tests of cognition, vision, and motor skills. Since these tests provide additional predictive value of driving performance beyond diagnosis alone, clinicians may use these tests to help predict whether a patient with AD can safely operate a motor vehicle.

A community based survey of cognitive functioning, highway-code performance and traffic accidents in a cohort of older drivers

BACKGROUND

The DVLA allows driving in early dementia contingent on regular medical assessment. GPs and psychiatrists require validated and accessible assessments. Some studies have suggested that cognitive testing has utility in the assessment of driving capacity in elderly drivers. One study raises the possibility of using a highway-code questionnaire as an adjunct to these tests.

METHOD

Two hundred drivers over the age of 65 were randomly selected from two GP surgeries. Baseline assessment comprised completion of a Highway Code questionnaire (DPHC-98), the Mini Mental State Examination (MMSE) and an abbreviated version of the Alzheimer's Disease Assessment Scale Cognitive Subsection (EURO-ADAS). A history of road traffic accidents (RTAs) over the preceding 5 years was obtained. At 12-month follow-up interview driving status of the subject and occurrence of RTAs were recorded. Predictive power of DPHC-98 and cognitive testing with regards RTAs were examined through logistic regression analysis.

RESULTS

Performance on the Highway Code questionnaire was identified as the only significant regression factor in the prediction of prospective RTAs. However, none of the logistic regression models were able to identify any drivers involved in RTAs either retrospectively or prospectively.

CONCLUSION

Cognitive tests are not linked with risk of driving accidents in older adults in any useful way.

A longitudinal study of drivers with Alzheimer disease

OBJECTIVE

The goal of this study was to define the natural progression of driving impairment in persons who initially have very mild to mild dementia.

METHODS

We studied 128 older drivers, including 84 with early Alzheimer disease (AD) and 44 age-matched control subjects without cognitive impairment. Subjects underwent repeated assessments of their cognitive, neurologic, visual, and physical function over 3 years. Self-reports of driving accidents and traffic violations were supplemented by reports from family informants and state records. Within 2 weeks of the office evaluation, subjects were examined by a professional driving instructor on a standardized road test.

RESULTS

At baseline, subjects with AD had experienced more accidents and performed more poorly on the road test, compared to controls. Over time, both groups declined in driving performance on the road test, with subjects with AD declining more than controls. Survival analysis indicated that while the majority of subjects with AD passed the examination at baseline, greater severity of dementia, increased age, and lower education were associated with higher rates of failure and marginal performance.

CONCLUSIONS

This study confirms previous reports of potentially hazardous driving in persons with early Alzheimer disease, but also indicates that some individuals with very mild dementia can continue to drive safely for extended periods of time. Regular follow-up assessments, however, are warranted in those individuals.

Computerized maze navigation and on-road performance by drivers with dementia

This study examined the ability of computerized maze test performance to predict the road test performance of cognitively impaired and normal older drivers. The authors examined 133 older drivers, including 65 with probable Alzheimer disease, 23 with possible Alzheimer disease, and 45 control subjects without cognitive impairment. Subjects completed 5 computerized maze tasks employing a touch screen and pointer as well as a battery of standard neuropsychological tests. Parameters measured for mazes included errors, planning time, drawing time, and total time. Within 2 weeks, subjects were examined by a professional driving instructor on a standardized road test modeled after the Washington University Road Test. Road test total score was significantly correlated with total time across the 5 mazes. This maze score was significant for both Alzheimer disease subjects and control subjects. One maze in particular, requiring less than 2 minutes to complete, was highly correlated with driving performance. For the standard neuropsychological tests, highest correlations were seen with Trail Making A (TrailsA) and the Hopkins Verbal Learning Tests Trial 1 (HVLT1). Multiple regression models for road test score using stepwise subtraction of maze and neuropsychological test variables revealed significant independent contributions for total maze time, HVLT1, and TrailsA for the entire group; total maze time and HVLT1 for Alzheimer disease subjects; and TrailsA for normal subjects. As a visual analog of driving, a brief computerized test of maze navigation time compares well to standard neuropsychological tests of psychomotor speed, scanning, attention, and working memory as a predictor of driving performance by persons with early Alzheimer disease and normal elders. Measurement of maze task performance appears to be useful in the assessment of older drivers at risk for hazardous driving.

Anxiety of Alzheimer's disease patients before and after a standardized on-road driving test

BACKGROUND

A large number of licensed elderly drivers are demented or are likely to become demented. On-road driving tests, a method often used to assess driver competency, are likely anxiety-provoking for elderly individuals. This article examines the relationship between anxiety and driving performance in a mildly demented and elderly control (EC) sample.

METHODS

Anxiety ratings of fear and tension, as assessed by visual analog scales, of 84 patients clinically diagnosed with mild Alzheimer's disease (AD) (68 safe/marginal and 16 unsafe drivers) were compared with those of 44 age- and education-equated safe/marginal EC participants, both before and after a standardized on-road driving test.

RESULTS

Analyses revealed significant positive correlations between AD patients' pre-road test and post-road test tension and post-road test fear ratings and total road test score. Subsequent analyses of variance showed no significant pre-road test differences in fear ratings between the three groups but significantly higher levels of tension among the unsafe AD participants. After adjusting for baseline group differences, unsafe AD drivers experienced stable or higher anxiety levels after road test, whereas both the EC and safe/marginal AD drivers endorsed a significant reduction in anxiety.

DISCUSSION

Unlike their safe EC and safe AD driver counterparts, unsafe AD patients reported continued elevated levels of fear and tension after the road test. Given these findings, we suggest that the most appropriate time for driving instructors to counsel patients regarding their driving skills might be directly after the road test.

Predictors of driving cessation in mild-to-moderate dementia

BACKGROUND

Although physicians in most provinces are mandated to report patients whose driving ability is impaired by illness, little is known about dementia-related factors associated with driving cessation. The purpose of our study was to explore factors that may affect the likelihood of driving cessation in a sample of elderly, community-dwelling patients with dementia.

METHODS

A 3-year prospective study, the Canadian Outcomes Study in Dementia (COSID) has enrolled 883 patients with mild-to-moderate dementia at 32 centres across Canada. Assessment tools included the Mini-Mental State Examination (MMSE) for cognition, the Global Deterioration Scale (GDS) for staging (severity), the Functional Autonomy Measurement System (SMAF) for function, and the Neuropsychiatric Inventory (NPI) for behaviour. Factors associated with the decision to quit driving after the baseline assessment were tested with Cox survival analysis.

RESULTS

Of 719 subjects who were or had been drivers, 203 (28.2%) were still driving at baseline. Over an observation period that averaged 23 months, 97 (48.5%) of 200 patients quit driving. Factors predictive of driving cessation included GDS (hazard ratio [HR] 1.68, 95% confidence interval [CI] 1.15-2.45), MMSE score (HR 0.90, 95% CI 0.83-0.97) and NPI findings (HR 1.63 for presence of > or = 3 behaviours, 95% CI 1.01-2.62). Among the NPI behaviours, when they were analyzed separately, agitation led to a decreased likelihood of driving cessation (p = 0.019), whereas apathy (p = 0.031) and hallucinations (p = 0.050) led to an increased likelihood.

INTERPRETATION

Cognitive impairment and behaviours such as agitation, apathy and hallucinations were significant predictors of driving cessation in patients with a mild to moderate degree of dementia. These findings should be considered when one counsels patients and their families.

Dementia and driving: autonomy versus safety

PURPOSE

This article reviews the effects of various types of dementia on driving skills, the available assessment measures, legal considerations, and the important role played by the nurse practitioner (NP) in the process of recommending driving cessation. It provides strategies and resources that may offer guidance to NPs who are attempting to balance the continued independence of patients with dementia, as represented by driving, with the safety not only of such patients but also of the public at large.

DATA SOURCES

A review of the biomedical literature, resources available on the World Wide Web, and illustrative case studies were used.

CONCLUSIONS

The diagnosis of dementia alone is often insufficient to determine driver competence because the topographic losses of dementia are complex. Recognizing when cessation should occur is made more difficult because objective assessment tools do not exist to predict impaired driving skills. Recommending driving cessation at the appropriate time can be a challenge for NPs, who must balance such a significant impact on the driver's autonomy with concerns about public safety if the patient continues to drive despite progressive impairment.

IMPLICATIONS FOR PRACTICE

The progressive loss of cognitive abilities in dementia presents a series of ongoing challenges for the patient throughout the disease continuum. Unfortunately, the recommendation to stop driving can present one of the more immediate issues confronting the patient, the family, and the healthcare provider. Failure to assess diminished driving skill can lead either to premature or to delayed driving cessation. Either outcome can have adverse effects on the patient, the patient's family, and public safety.

Neuropsychological deficits associated with driving performance in Parkinson's and Alzheimer's disease

Neuropsychological and motor deficits in Parkinson's disease that may contribute to driving impairment were examined in a cohort study comparing patients with Parkinson's disease (PD) to patients with Alzheimer's disease (AD) and to healthy elderly controls. Nondemented individuals with Parkinson's disease [Hoehn & Yahr (H&Y) stage I-III], patients with Alzheimer's disease [Clinical Demetia Rating scale (CDR) range 0-1], and elderly controls, who were actively driving, completed a neuropsychological battery and a standardized road test administered by a professional driving instructor. On-road driving ability was rated on number of driving errors and a global rating of safe, marginal, or unsafe. Overall, Alzheimer's patients were more impaired drivers than Parkinson's patients. Parkinson's patients distinguished themselves from other drivers by a head-turning deficiency. Drivers with neuropsychological impairment were more likely to be unsafe drivers in both disease groups compared to controls. Compared to controls, unsafe drivers with Alzheimer's disease were impaired across all neuropsychological measures except finger tapping. Driving performance in Parkinson's patients was related to disease severity (H&Y), neuropsychological measures [Rey Osterreith Complex Figure (ROCF), Trails B, Hopkins Verbal List Learning Test (HVLT)-delay], and specific motor symptoms (axial rigidity, postural instability), but not to the Unified Parkinson Disease Rating Scale (UPDRS) motor score. Multifactorial measures (ROCF, Trails B) were useful in distinguishing safe from unsafe drivers in both patient groups.

Neuropsychological deficits associated with driving performance in Parkinson's and Alzheimer's disease

Neuropsychological and motor deficits in Parkinson's disease that may contribute to driving impairment were examined in a cohort study comparing patients with Parkinson's disease (PD) to patients with Alzheimer's disease (AD) and to healthy elderly controls. Nondemented individuals with Parkinson's disease [Hoehn & Yahr (H&Y) stage I-III], patients with Alzheimer's disease [Clinical Demetia Rating scale (CDR) range 0-1], and elderly controls, who were actively driving, completed a neuropsychological battery and a standardized road test administered by a professional driving instructor. On-road driving ability was rated on number of driving errors and a global rating of safe, marginal, or unsafe. Overall, Alzheimer's patients were more impaired drivers than Parkinson's patients. Parkinson's patients distinguished themselves from other drivers by a head-turning deficiency. Drivers with neuropsychological impairment were more likely to be unsafe drivers in both disease groups compared to controls. Compared to controls, unsafe drivers with Alzheimer's disease were impaired across all neuropsychological measures except finger tapping. Driving performance in Parkinson's patients was related to disease severity (H&Y), neuropsychological measures [Rey Osterreith Complex Figure (ROCF), Trails B, Hopkins Verbal List Learning Test (HVLT)-delay], and specific motor symptoms (axial rigidity, postural instability), but not to the Unified Parkinson Disease Rating Scale (UPDRS) motor score. Multifactorial measures (ROCF, Trails B) were useful in distinguishing safe from unsafe drivers in both patient groups.