Driving performance in persons with mild senile dementia of the Alzheimer type

Drivers with dementia and outcomes of becoming lost while driving

Researchers of driving and dementia have reported that drivers with early Alzheimer's disease (AD) may continue to drive for extended periods of time, as long as their driving is evaluated or monitored. The earliest symptoms of AD are known to include loss of recent memory and the inability to recognize familiar environments. In an exploratory study, we examined 207 reports of lost drivers with dementia over 10 yr reported by newspapers and media. Seventy AD drivers were not found, 32 drivers were found dead, and 116 drivers were found alive, although of those found alive, 35 people were found injured. Miles driven and days missing were also reported in some cases, in addition to cause of death (such as drowning or exposure to weather). Becoming lost may have serious consequences. Additional research is needed in this area to more clearly understand the consequences of becoming lost while driving.

The older adult driver with cognitive impairment: "It's a very frustrating life"

Although automobiles remain the transportation of choice for many older adults, late-life cognitive impairment and dementia often impair the ability to drive safely. However, there is no commonly used method of assessing dementia severity in relation to driving, no consensus on the assessment of older drivers with cognitive impairment, and no gold standard for determining driving fitness. Yet clinicians are called on by patients, their families, other health professionals, and often their state's Department of Motor Vehicles to assess their patients' fitness to drive and to make recommendations about driving privileges. This article describes the challenges of driving with cognitive impairment for both the patient and caregiver, summarizes the literature on dementia and driving, discusses evidence-based assessment of fitness to drive, and addresses important ethical and legal issues. It also describes the role of physician assessment, referral for neuropsychological testing, screening for functional ability, tools to assess dementia severity, driving evaluation clinics, and Department of Motor Vehicles referrals that may assist with evaluation. Lastly, it discusses mobility counseling (eg, exploration of transportation alternatives), because health professionals need to address this important issue for older adults who lose the ability to drive. The application of a comprehensive, interdisciplinary approach to the older driver with cognitive impairment will have the best opportunity to enhance patients' social connectedness and quality of life while meeting their psychological and medical needs and maintaining personal and public safety.

Practice parameter update: evaluation and management of driving risk in dementia: report of the Quality Standards Subcommittee of the American Academy of Neurology

OBJECTIVE

To review the evidence regarding the usefulness of patient demographic characteristics, driving history, and cognitive testing in predicting driving capability among patients with dementia and to determine the efficacy of driving risk reduction strategies.

METHODS

Systematic review of the literature using the American Academy of Neurology's evidence-based methods.

RECOMMENDATIONS

For patients with dementia, consider the following characteristics useful for identifying patients at increased risk for unsafe driving: the Clinical Dementia Rating scale (Level A), a caregiver's rating of a patient's driving ability as marginal or unsafe (Level B), a history of crashes or traffic citations (Level C), reduced driving mileage or self-reported situational avoidance (Level C), Mini-Mental State Examination scores of 24 or less (Level C), and aggressive or impulsive personality characteristics (Level C). Consider the following characteristics not useful for identifying patients at increased risk for unsafe driving: a patient's self-rating of safe driving ability (Level A) and lack of situational avoidance (Level C). There is insufficient evidence to support or refute the benefit of neuropsychological testing, after controlling for the presence and severity of dementia, or interventional strategies for drivers with dementia (Level U).

Validity and Critical Driving Errors of On-Road Assessment for Older Drivers

OBJECTIVES. We examined the validity of our on-road driving assessment to quantify its outcomes.

METHOD. Older drivers (N = 127) completed a driving assessment on a standardized road course. Measurements included demographics, driving errors, and driving test outcomes; a categorical global rating score (pass–fail); and the sum of maneuvers (SMS) score (0–273).

RESULTS. There were significant differences in the SMS (F = 29.9, df = 1 p ≤ .001) between drivers who passed the driving test and those who failed. The SMS cutoff value of 230 points was established as the criterion because it yielded the most optimal combination of sensitivity (0.91) and specificity (0.87). The strongest predictors of failure were adjustment to stimuli and lane maintenance errors.

CONCLUSION. The SMS differentiated between passing and failing drivers and can be used to inform clinical decision making.

Test Acceptability and Confidence Levels in Older Adults Referred for Fitness-to-Drive Evaluations

In this study, we examined confidence and face validity or client acceptability of tests used in a Veterans Affairs Medical Center driving clinic. The clinic used evidence-based off-road tests and adopted the Washington University Road Test (WURT) as a performance-based on-road examination. Forty-three clients consented to participate in the study; most were male with an average age of 78.2 years (standard deviation = 12.6). In general, a trend existed toward higher client acceptability of tests adopted from the Neuropsychological Assessment Battery (Stern & White, 2003) and the WURT than of other off-road measures. Confidence decreased after administration of the psychometric test battery, yet it increased after the on-road evaluations despite a 47% failure rate in the sample. Additional study is needed on test acceptability because it may have the potential to increase understanding, compliance, or both with driving recommendations. Additional research is also needed to examine client confidence levels and their potential impact on performance during the driving evaluation process.

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.

Effects of Alzheimer's disease and mild cognitive impairment on driving ability: a controlled clinical study by simulated driving test

OBJECTIVE

To assess the effects of Alzheimer's disease (AD) and Mild Cognitive Impairment (MCI) on simulated car driving ability.

METHODS

Twenty patients with a probable AD of mild severity (Clinical Dementia Rating, CDR = 1) were compared with 20 subjects with MCI (CD = 0.5), and a group of age-matched neurologically normal controls on a driving simulation task. Measures of driving competence included the length of run, the number of infractions (omission of stop at pedestrian crossings, speed limits violation), the number of stops at traffic lights, the mean time to collision, and the number of off-road events. Results in the driving competence measures were correlated with scores obtained from simple visual reaction times and mini-mental state examination (MMSE).

RESULTS

The patients with mild AD performed significantly worse than MCI subjects and controls on three simulated driving measures, length of run and mean time to collision (p < 0.001), and number of off-road events (p < 0.01). MCI subjects had only a significantly shorter time-to-collision than healthy controls (p < 0.001). Simple visual reaction times were significantly longer (p < 0.001) in patients with AD, compared to MCI and healthy controls, and showed a borderline significant relation (p = 0.05) with simulated driving scores. Driving performance in the three groups did not significantly correlate with MMSE score as measure of overall cognitive function.

CONCLUSIONS

Mild AD significantly impaired simulated driving fitness, while MCI limitedly affected driving performance. Unsafe driving behaviour in AD patients was not predicted by MMSE scores.

Driving assessment for maintaining mobility and safety in drivers with dementia

BACKGROUND

Demographic changes are leading to an increase in the number of older drivers: as dementia is an age-related disease, there is also an increase in the numbers of drivers with dementia. Dementia can impact on both the mobility and safety of drivers, and the impact of formal assessment of driving is unknown in terms of either mobility or safety. Those involved in assessment of older drivers need to be aware of the evidence of positive and negative effects of driving assessment. Although cognitive tests are felt by some authors to have poor face and construct validity for assessing driving performance, extrapolating from values in one large-scale prospective cohort study, the cognitive test that most strongly predicted future crashes would, if used as a screening tool, potentially prevent six crashes per 1000 people over 65 screened, but at the price of stopping the driving of 121 people who would not have had a crash.

PRIMARY OBJECTIVES

1. To assess whether driving assessment facilitates continued driving in people with dementia 2. To assess whether driving assessment reduces accidents in people with dementia.

SECONDARY OBJECTIVE

To assess the quality of research on assessment of drivers with dementia.

SEARCH STRATEGY

The Cochrane Dementia Group's Specialized Register was searched on 30 October 2007 using the terms: driving or driver* or "motor vehicle*" or "car accident*" or "traffic accident*" or automobile* or traffic. This register contains records from major healthcare databases, ongoing trial databases and grey literature sources and is updated regularly.

SELECTION CRITERIA

We sought randomized controlled trials prospectively evaluating drivers with dementia for outcomes such as transport mobility, driving cessation or motor vehicle accidents following driving assessment.

DATA COLLECTION AND ANALYSIS

Each author retrieved studies and assessed for primary and secondary outcomes, study design and study quality.

MAIN RESULTS

No studies were found that met the inclusion criteria. A description and discussion of the driving literature relating to assessment of drivers with dementia relating to the primary objectives is presented.

AUTHORS' CONCLUSIONS

In an area with considerable public health impact for drivers with dementia and other road users, the available literature fails to demonstrate the benefit of driver assessment for either preserving transport mobility or reducing motor vehicle accidents. Driving legislation and recommendations from medical practitioners requires further research that addresses these outcomes in order to provide the best outcomes for both drivers with dementia and the general public.

Using the Attention Network Test to predict driving test scores

Driving is a complex multi-factorial task that taps underlying mechanisms of cognition and attention. Not surprisingly, therefore, many tests of cognition and attention are significantly associated with driving outcomes. In this article, we introduce driving researchers and clinicians with an interest in driving to the Attention Network Test (ANT), which to our knowledge has not previously been used in driving research. It is a recently developed test that is based on a neural network model of the human attention system. It combines elements of Posner's cuing paradigm [Posner, M.I., 1980. Orienting of attention. Quarterly Journal of Experimental Psychology 32, 3-25.] with the Eriksen & Eriksen flanker task [Eriksen, B.A., Eriksen, C.W., 1974. Effects of noise letters upon the identification of a target letter in a nonsearch task. Perception & Psychophysics 16, 143-149.], and provides measures of three distinct functions of attention: alerting, orienting, and executive function. Our results demonstrate that the ANT has very good concurrent validity with the Useful Field of View (UFOV), and that it is comparable to UFOV in its ability to predict road test scores for a simulated drive. These findings suggest that further investigation of the usefulness of the ANT as a tool for driving researchers and clinicians is merited.

Patients with minimal hepatic encephalopathy have poor insight into their driving skills

BACKGROUND & AIMS

Minimal hepatic encephalopathy (MHE) is associated with impaired driving skills. It is not clear whether patients have insight into this. The Driving Behavior Survey (DBS) is a validated self- or observer-administered questionnaire. DBS consists of a total score (maximum, 104) and an attention-related driving skills section (maximum, 40). DBS was used to compare self-assessment with observer-assessment of driving skills in cirrhotic patients tested for MHE.

METHODS

Forty-seven nonalcoholic cirrhotic patients and 40 controls underwent psychometric tests, DBS, and driving simulation with navigation/driving tasks. An adult familiar with the subject's driving completed the DBS independently. Simulator performances, total DBS scores, and driving skill scores were compared between/within groups (MHE+, MHE-, and controls) with respect to self-assessment and observer assessment.

RESULTS

Thirty-six patients were MHE+ and 11 were MHE-. MHE+ had a significantly higher simulator crash (MHE+, 3; MHE-, 1.2; controls, 1.7; P = .001) and illegal turn rate (MHE+, 1.2; MHE-, 0.3; controls, 0.1; P = .0001). Despite this worse performance, MHE+ patients rated themselves similar to MHE- patients and control groups on total (P = .28) and driving skills scores (P = .19). Observer assessment in MHE+ was significantly lower for total (P = .0001) and driving skills (P = .0001) compared with observer assessment for MHE- patients and control groups. MHE+ patients were rated significantly lower on driving skills (34 vs 37; P = .02) and trended lower in the total score (P = .08) by observers compared with self-ratings. In contrast, MHE- and control groups rated themselves similar to their observers on driving skills and total DBS scores.

CONCLUSIONS

MHE patients have poor insight into their driving skills. A part of the MHE patient's clinical interview should be to increase awareness of this driving impairment.

Predicting driving performance in older adults: we are not there yet!

OBJECTIVE

We set up this study to determine the predictive value of approaches for which a statistical association with driving performance has been documented.

METHODS

We determined the statistical association (magnitude of association and probability of occurrence by chance alone) between four different predictors (the Mini-Mental State Examination, Trails A test, Useful Field of View [UFOV], and a composite measure of past driving incidents) and driving performance. We then explored the predictive value of these measures with receiver operating characteristic (ROC) curves and various cutoff values.

RESULTS

We identified associations between the predictors and driving performance well beyond the play of chance (p < .01). Nonetheless, the predictors had limited predictive value with areas under the curve ranging from .51 to .82.

CONCLUSIONS

Statistical associations are not sufficient to infer adequate predictive value, especially when crucial decisions such as whether one can continue driving are at stake. The predictors we examined have limited predictive value if used as stand-alone screening tests.

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.

Objective metamemory testing captures awareness of deficit in Alzheimer's disease

For reasons that remain unknown, there is marked inter-person variability in awareness of episodic memory loss in patients with Alzheimer's disease (AD). Existing research designs, primarily subjective in nature, have been at a relative disadvantage for evaluating disordered metamemory and its relation to the clinical and neuropathological heterogeneity of AD, as well as its prognosis for various disease outcomes. The current study sought to establish an objective means of evaluating metamemory in AD by modifying traditional metacognitive paradigms in which participants are asked to make predictions regarding their own memory performance. Variables derived from this measure were analyzed in relation to clinically rated awareness for memory loss. As predicted, a range of awareness levels existed across patients with mild to moderate AD (n=24) and clinical ratings of awareness (CRA) were significantly associated with verbal episodic memory monitoring (r = .46, p = .03). Further, patients who were rated as aware of their memory loss remained well calibrated over the course of the task whereas those rated as relatively unaware grew over-confident in their predictions [F (1, 33) = 4.19, p = .02]. Findings suggest that over-confidence may be related to impaired online error recognition and compromised use of metamemory strategies such as the Memory for Past Test (MPT) heuristic. Importantly, clinically rated awareness did not vary as a function of demographic variables, global cognition, or verbal memory. However, participants characterized as relatively unaware were impaired on a nonverbal memory task as compared to aware participants [F (1, 20) = 6.98, p = .02]. The current study provides preliminary support for the use of a recognition-based verbal episodic memory monitoring task as a quantitative measure of awareness for memory loss in AD, and offers insight into the manner in which metamemory breaks down. Discrepancies in nonverbal memory across the two awareness groups provide preliminary support for the idea that metamemory variability in AD may be related to the neuroanatomic presentation of the disease, with disordered awareness potentially reflective of a critical level of right hemisphere involvement.

Sensory-motor and cognitive tests predict driving ability of persons with brain disorders

OBJECTIVE

Brain disorders can lead to a decreased ability to perform the physical and cognitive functions necessary for safe driving. This study aimed to determine how accurately a battery of computerized sensory-motor and cognitive tests (SMCTests) could predict driving abilities in persons with brain disorders.

METHODS

SMCTests and an independent on-road driving assessment were applied to 50 experienced drivers with brain disorders referred to a hospital-based driving assessment service. The patients comprised 36 males and 14 females, a mean age of 71.3 years (range 43-85 years) and diagnoses of 35 stroke, 4 traumatic brain injury, 4 Alzheimer's disease, and 7 other. Binary logistic regression (BLR) and nonlinear causal resource analysis (NCRA) were used to build model equations for prediction of on-road driving ability based on SMCTests performance.

RESULTS

BLR and NCRA correctly classified 94% and 90% of referrals respectively as on-road pass or fail. Leave-one-out cross-validation estimated that BLR and NCRA would correctly predict the classification of 86% and 76% respectively of an independent referral group as on-road pass or fail.

CONCLUSIONS

Compared with other studies, SMCTests have shown the highest predictive accuracy against true on-road driving ability as estimated in an independent data set and in persons with brain disorders. SMCTests also have the advantage of being able to comprehensively and objectively assess both sensory-motor and higher cognitive functions related to driving.

Insight and danger in Alzheimer's disease

To determine the frequency, and demographic and clinical correlates of dangerous behaviours in Alzheimer's disease (AD). We assessed a consecutive series of 278 patients with AD and 45 age-comparable healthy controls with a comprehensive psychiatric and neuropsychological evaluation. Caregivers rated the frequency of patients' exposure to dangerous situations or commission of dangerous behaviours. The frequency of dangerous behaviours was 16% in the AD group and 2% in the healthy control group. The presence of anosognosia was associated with a threefold increase in the risk of dangerous behaviours, but there was no significant association between dangerous behaviours and patients' age, years of education, diagnosis of major or minor depression and presence of suicide ideation. Sixteen per cent of a consecutive series of patients with AD had dangerous behaviours during the month preceding the clinical evaluation. Anosognosia was the main clinical correlate of dangerous behaviours in this population.

Systematic Review of Driving Risk and the Efficacy of Compensatory Strategies in Persons with Dementia

OBJECTIVES

To determine whether persons with dementia are at greater driving risk and, if so, to estimate the magnitude of this risk and determine whether there are efficacious methods to compensate for or accommodate it.

DESIGN

Systematic review of the literature.

SETTING

Case-control studies.

PARTICIPANTS

Drivers with a diagnosis of dementia.

MEASUREMENTS

Most studies used state and caregiver reported crash rates, performance-based road tests, and driving simulator evaluations as their outcome measures.

RESULTS

Twenty-three studies were included. Drivers with dementia universally exhibited poorer performance on road tests and simulator evaluations, although only one study using an objective measure of motor vehicle crashes was able to show that drivers with dementia were involved in more crashes than control subjects. No studies were found that examined the efficacy of methods to compensate for or accommodate their worse driving performance.

CONCLUSION

Drivers with dementia are poorer drivers than cognitively normal drivers, but studies have not consistently demonstrated higher crash rates. Clinicians and policy makers must take these findings into account when addressing issues pertinent to drivers with a diagnosis of dementia.

Driving abilities in frontotemporal dementia patients

OBJECTIVE

To evaluate driving competency and the relationship between neuropsychiatric symptoms and driving behavior in frontotemporal dementia (FTD) patients.

METHODS

Fifteen patients with a diagnosis of FTD and 15 healthy controls were administered a driving simulation task. Measures of driving performance and neuropsychiatric symptoms were assessed.

RESULTS

The FTD patients received more speeding tickets, ran more stop signs and were involved in more off-road crashes and collisions than the controls. The patients' overall average speed was significantly higher. Driving performance was correlated with agitated behavior.

CONCLUSIONS

Behavioral changes characteristic of FTD patients have an impact on their driving skills leading to inappropriate driving behavior.

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.

Clinical Utility of Office-Based Cognitive Predictors of Fitness to Drive in Persons with Dementia: A Systematic Review

OBJECTIVES

To perform a systematic review of evidence available regarding in-office cognitive tests that differentiate safe from unsafe drivers with dementia.

DESIGN

A comprehensive literature search of multiple databases including Medline, CINAHL, PsychInfo, AARP Ageline, and Sociofile from 1984 to 2005 was performed. This was supplemented by a search of Current Contents and a review of the bibliographies of all relevant articles.

SETTING

English prospective cohort, retrospective cohort, and case-control studies that used accepted diagnostic criteria for dementia or Alzheimer's disease and that employed one of the primary outcomes of crash, simulator assessment, or on-road assessment were included.

PARTICIPANTS

Two reviewers.

MEASUREMENTS

The reviewers independently assessed study design, main outcome of interest, cognitive tests, and population details and assigned a Newcastle-Ottawa quality assessment rating.

RESULTS

Sixteen articles met the inclusion criteria. Tests recommended by guidelines (e.g., the American Medical Association (AMA) and Canadian Medical Association guidelines) for the assessment of fitness to drive did not demonstrate robustly positive findings (e.g., Mini-Mental State Examination, Trails B) or were not evaluated in any of the included studies (e.g., Clock Drawing). Fifteen studies did not report any cutoff scores.

CONCLUSION

Without validated cutoff scores, it is impossible to employ tests in a standardized fashion in front-line clinical settings. This study identified a research gap that will prevent the development of evidence-based guidelines. Recommendations to address this gap are that driving researchers routinely perform cutoff score analyses and that stakeholder organizations (e.g., AMA, American Geriatrics Society) sponsor consensus fora to review driving research methodologies.

Visual attention and older drivers: the contribution of inhibition of return to safe driving

Increasing data suggest that visual attention may be impaired in some older drivers, and that such impairment may be related to poorer driving abilities and a higher crash risk. Because effective scanning of the environment is important for safe driving, the authors sought to examine the relationship between a reflexive visual attention mechanism and driving. To examine this issue the authors conducted a preliminary study using the inhibition of return (IOR) paradigm, which has been labeled as a fundamental search mechanism. Forty-one drivers aged 55 and over completed two on-road driving evaluations and IOR testing. After accounting for the contribution of age, IOR statistically predicted overall driving evaluation scores (p = .045), and the number of errors in scanning the environment (p = .031). To the authors' knowledge these findings represent the first documentation of a relationship between IOR and driving. The results are informative regarding the importance of reflexive visual attention mechanisms towards safe driving.

Systematic Review of the Optimal Frequency of Follow-up in Persons With Mild Dementia Who Continue to Drive

Fitness-to-drive guidelines commonly indicate that persons with mild dementia may be safe to drive but that periodic reevaluation is required. This paper presents the findings of a systematic review of primary evidence regarding the optimal timing of follow-up in persons with mild dementia who continue to drive. A search of Medline, CINAHL, PsychInfo, AARP Ageline, and Sociofile from 1984 to 2005 was performed. No published studies focus primarily on the timing of follow-up of drivers with mild dementia. Three studies present longitudinal data that the authors reference when recommending periodicity of follow-up. This study identifies a concerning research gap in the field of dementia and driving. To provide better evidence to guide recommendations for periodicity of follow-up, 3 recommendations are proposed: (1) that prospective cohort driving research be undertaken to follow patients with mild dementia who continue to drive, (2) that data from such longitudinal research be presented as survival analyses, and (3) that existing research on the progression rates of Alzheimer disease be employed as a default until the first 2 recommendations are realized.

Les conducteurs âgés en bonne santé font plus d’erreurs et d’oublis que d’infractions

OBJECTIVES

Driving is an important part of everyday life for the elderly today. Older drivers are suspected to be involved in more automobile accidents than younger adults. Although healthcare professionals are aware of specific diseases and impairments that increase accident risks, they cannot distinguish safe from unsafe drivers among the healthy elderly population in general practice. Previous English studies of younger populations differentiate three main types of bad driving that are associated with accident involvement: violations, errors, and lapses. The aim of this study was to assess the driving behavior associated with car crashes in a healthy elderly population.

METHOD

This prospective survey of healthy drivers aged 65 years or older living in the community asked subjects about their habitual driving and accident history in the past three years. Subjects also completed the French version of the Manchester Aging Driver Questionnaire, which contains 24 items, scored from 0 (never) to 5 (nearly all the time) and yields three sub-scales: errors, violations, and lapses. Simple logistic regression, adjusted for age and sex, was used to analyze associations between the questionnaire results and driving history.

RESULTS

These elderly drivers (mean age: 69 years) reported primarily lapses (mean: 5.42) but also violations (mean: 3.76) and errors (mean: 2.12). In all, 237 drivers (27%) reported accidents: 29.4% of the men compared with 20.2% of the women (p<0.01). After adjustment for age and gender, the logistic regression showed four specific errors and one lapse to be associated with accidents: "Queuing to turn left onto main road, you pay such close attention to the main stream that you nearly hit the car in front" (OR: 1.71; 95% CI: 1.05-2.08); "On turning left, nearly hit a cyclist who has come up on your side" (OR: 1.58; 95% CI: 1.01-2.45); "Underestimate the speed of an oncoming vehicle when overtaking" (OR: 1.48; 95% CI: 1.09-2.02); "Brake too quickly on a slippery road, or steer the wrong way into a skid" (OR: 1.60; 95% CI: 1.15-2.29); and "Hit something when reversing that you had not previously seen" (OR: 1.73; 95% CI: 1.19-2.50).

CONCLUSION

As previously reported, errors and lapses are more common than violations among healthy elderly drivers. Five specific actions were associated with accident risk. The ADQ is a short, simple survey questionnaire that is useful for screening bad driving behavior in elderly drivers and for promoting safe driving practice among them.

Driving Cessation in Older Adults With Dementia of the Alzheimer's Type

The psychometric profile of 143 drivers with dementia who stopped driving did not differ from that of 58 individuals with dementia of similar severity who still drove. The reasons given for driving cessation by drivers with dementia as reported by a collateral source are reported.

Sustained attention in mild Alzheimer's disease

The vigilance decrement in perceptual sensitivity was examined in 10 patients with mild Alzheimer's disease (AD) and 20 age-matched controls. A visual high-event rate digit-discrimination task lasting 7.2 min. (six 1.2 min blocks) was presented at different levels of stimulus degradation. Previous studies have shown that sensitivity decrements (d') over time at high-stimulus degradation result from demands on effortful processing. For all degradation levels, the overall level of vigilance (d') was lower in AD patients than in controls. All participants showed sensitivity decrement over blocks, with greater decrement at higher degradation levels. AD patients exhibited greater sensitivity decrement over time at the highest degradation level they all could perform relative to control participants. There were no concomitant changes in either response bias (C) or response times. The results indicate that mild AD patients have overall lower levels of vigilance under conditions that require both automatic and effortful processing. Mild AD patients also exhibit a deficit in the maintenance of vigilance over time under effortful processing conditions. Although the sample of AD patients was small, results further suggest that both possible and probable AD patients had greater sensitivity decrement over time at the highest degradation level than did control participants, but only probable AD patients had lower overall levels of vigilance. In the possible AD patients as a group, the decrement in vigilance occurred in the absence of concurrent deficits on standard attentional tasks, such as the Stroop and Trail Making tests, suggesting that deficits in vigilance over time may appear earlier than deficits in selective attention.

Self-rated driving performance among elderly drivers referred for driving evaluation

PURPOSE

To explore whether elderly drivers of varying driving skill levels (1) differ in their perception of their driving evaluation performance and (2) determine if self-rated driving evaluation performance is related to cognitive ability.

METHODS

One hundred and fifty-two drivers aged 65 years or older and referred for a driving evaluation were enrolled into the study. Subjects were asked the question, "how well do you think you will perform today on your driving evaluation compared to others your own age?" Subjects also completed the Mini-Mental State Exam and a 30-min drive on a STISIM Drivetrade mark simulation (Systems Technology, Inc., Hawthorne, CA). Only 47 subjects completed both the simulated drive and self-rated item.

RESULTS

Sixty-five percent of drivers rated themselves as performing better on a driving test than others of their age. Another 31.9% felt they would perform the same as others of their age on a driving test. A 50.0% of those considering themselves "a little better" and 52.9% of those considering themselves "a lot better" had an unsafe driving performance. As self-rated driving evaluation performance increased, there was a significantly increased risk of unsafe driving (p=0.02) in the study population. Drivers who considered themselves at least a little better than others of their age were over four times more likely to be unsafe drivers compared to others who believed they were comparable to or worse than other drivers of their age (RR=4.13, 95% CI=1.08-15.78). There was no significant difference in MMSE between self-rating groups (p=0.76).

CONCLUSION

Older drivers assign high ratings to their driving performance, even in the presence of suspected skill decline. Cognitive ability was not related to self-rated driving evaluation performance.

Clinician assessment of the driving competence of patients with dementia

OBJECTIVES

To determine the validity and reliability of clinician ratings of the driving competence of patients with mild dementia.

DESIGN

Observational study of a cross-section of drivers with mild dementia based on chart review by clinicians with varying types of expertise and experience.

SETTING

Outpatient dementia clinic.

PARTICIPANTS

Fifty dementia subjects from a longitudinal study of driving and dementia.

MEASUREMENTS

Each clinician reviewed information from the clinic charts and the first study visit. The clinician then rated the drivers as safe, marginal, or unsafe. A professional driving instructor compared these ratings with total driving scores on a standardized road test and categorical ratings of driving competence. Clinicians also completed a visual analog scale assessment of variables that led to their determinations of driving competence.

RESULTS

Accuracy of clinician ratings ranged from 62% to 78% for the instructor's global rating of safe versus marginal or unsafe. In general, there was moderate accuracy and interrater reliability. Accuracy could have been improved in the least-accurate raters by greater attention to dementia duration and severity ratings, as well as less reliance on the history and physical examination. The most accurate predictors were clinicians specially trained in dementia assessment, who were not necessarily the most experienced in their years of clinical experience.

CONCLUSION

Although a clinician may be able to identify many potentially hazardous drivers, accuracy is insufficient to suggest that a clinician's assessment alone is adequate to determine driving competence in those with mild dementia.

Driver landmark and traffic sign identification in early Alzheimer's disease

OBJECTIVE

To assess visual search and recognition of roadside targets and safety errors during a landmark and traffic sign identification task in drivers with Alzheimer's disease.

METHODS

33 drivers with probable Alzheimer's disease of mild severity and 137 neurologically normal older adults underwent a battery of visual and cognitive tests and were asked to report detection of specific landmarks and traffic signs along a segment of an experimental drive.

RESULTS

The drivers with mild Alzheimer's disease identified significantly fewer landmarks and traffic signs and made more at-fault safety errors during the task than control subjects. Roadside target identification performance and safety errors were predicted by scores on standardised tests of visual and cognitive function.

CONCLUSIONS

Drivers with Alzheimer's disease are impaired in a task of visual search and recognition of roadside targets; the demands of these targets on visual perception, attention, executive functions, and memory probably increase the cognitive load, worsening driving safety.

Driving scenes test of the Neuropsychological Assessment Battery (NAB) and on-road driving performance in aging and very mild dementia

The Driving Scenes test of the new Neuropsychological Assessment Battery (NAB; [Stern, R.A., & White, T. (2003a). Neuropsychological Assessment Battery. Lutz, FL: Psychological Assessment Resources, Inc.]) measures several aspects of visual attention thought to be important for driving ability. The current study examined the relationship between scores on the Driving Scenes test and on-road driving performance on a standardized driving test. Healthy participants performed significantly better on the Driving Scenes test than did very mildly demented participants. A correlation of 0.55 was found between the brief, office-based Driving Scenes test and the 108-point on-road driving score. Furthermore, the Driving Scenes test scores differed significantly across the driving instructor's three global ratings (safe, marginal, and unsafe), and results of a discriminant function analysis indicated that the Driving Scenes test correctly classified 66% of participants into these groups. Thus, the new NAB Driving Scenes test appears to have good ecological validity for real-world driving ability in normal and very mildly demented older adults.

Prediction of on-road driving performance in patients with early Alzheimer's disease

OBJECTIVES

Physicians and family members frequently are asked to provide information about driving ability in patients with Alzheimer's disease (AD), yet there has been little research on the validity of their assessments of driving performance.

DESIGN

Cross-sectional.

SETTING

Participants were recruited from the neurology department of a community hospital affiliated with Brown Medical School.

PARTICIPANTS

Participants included 75 older adults (17 with mild AD, 33 with very mild AD, and 25 elderly controls).

MEASUREMENTS

The participant him/herself, an informant, and an experienced neurologist rated each participant's driving ability on a 3-point rating scale (safe, marginal, unsafe). A professional driving instructor also completed a standardized 108-point on-road driving assessment of each participant and then rated driving ability on the 3-point scale. Ratings were compared with the on-road driving score and with each other.

RESULTS

Only the neurologist's rating of the participants' driving abilities was significantly related to on-road driving score. When related to the instructor's safety rating, the neurologist's ratings were the most sensitive and specific. Mini-Mental State Examination score was a borderline covariate for the neurologist's rating. Overall, the instructor was the most stringent rater of participant driving ability, followed by the neurologist, the informant, and the participant.

CONCLUSION

An experienced neurologist's assessment of driving competence may be a valid predictor of driving performance of patients with early AD.

Driving and dementia: a review of the literature

The purpose of this article is to review the literature on the ability of individuals with dementia to drive an automobile. Based on a review of the literature, several factors were identified that may be useful in differentiating between people with dementia who presently remain safe drivers from those who have progressed to impaired driving. These factors include disease duration and severity, sex, patient self-assessment, family assessment, neuropsychological measures, findings on road evaluations, and driving simulator testing. The approach of the physician to driving and dementia is addressed, including in-office screening, referral for on-road driving assessments, and the potential for physician reporting to state agencies.

Association between older driver characteristics, on-road driving test performance, and crash liability

From May 1999, a new system for licensing older drivers was introduced in New Zealand. It included a practical on-road driving test with expanded scope, to be completed every two years from the time the driver turns 80. The relationship between crashes and test performance needed to be studied to inform the debate regarding the testing system. The population studied was all drivers who entered this licensing system during its first three years of operation. They were defined as crash involved if they were involved in an injury crash during the two years following their first licensure under the new system. Logistic regression was used to describe the risk of crash involvement in terms of driving test performance and other driver characteristics. Each driving test failure was associated with a 33% increase in the odds of crash involvement (95% CI 14% to 55%), controlling for age, gender, minor traffic violations, and whether the older driver lived with another licensed driver or not. Minor traffic violations in the two years following the driving test were associated with twice the odds of crash involvement. These results suggest that the new on-road driving test does identify older driver behaviors or limitations that are related to crash liability. It is anticipated that the results presented here will provide essential information for discussing older driver licensing systems, whose impact will grow in importance as the population of drivers ages.

Older driver crash rates in relation to type and quantity of travel

It is a well-established phenomenon that, notwithstanding their overall good crash record, older drivers have a higher than average rate of involvement in injury crashes when the rate is calculated by dividing crash numbers by distance driven. It has been hypothesised that at least some of this higher crash rate is an artefact of the different nature of driving undertaken by many older drivers. For example, driving in congested urban environments provides more opportunities for collisions than driving the same distance on a motorway. However, there have been few opportunities to investigate this theory, as relevant data are difficult to acquire. High-quality data from the New Zealand Travel Survey (1997/1998) were combined with crash data to enable a statistical model to estimate the risk of driver groups under various driving conditions characterised by the type of road used, time of day, day of week, and season of year. Despite elevated crash risks per distance driven compared with middle-aged drivers for most road types, older drivers were as safe as any other age group when driving on motorways. Accounting for the fragility of older drivers and their passengers in the risk estimates for other road types, older drivers appeared to have daytime risks comparable to 25-year-olds and night-time risks as low as any other age group. The driving patterns of older drivers (in terms of when and where they drive) were estimated to minimize their risks in comparison with the driving patterns of other age groups. These results are of interest to both policy makers and transportation planners working against the background of inevitable increases in the number of older drivers as the population ages.

The Relationship Between Neuropsychological Functioning and Driving Ability in Dementia: A Meta-Analysis

A meta-analysis of 27 primary studies was conducted to examine the relationship between neuropsychological functioning and driving ability for adults with dementia. When studies using a control group were included, the relationship between cognitive measures and on-road or non-road driving measures was significant for all reported domains; mean correlations ranged from.35 to.65. Caregiver reports of driving ability and cognitive variables were correlated significantly only on measures of mental status and visuospatial skills. When studies using a control group were excluded, moderate mean correlations were observed for visuospatial skills and on-road or non-road measures, and for mental status with non-road tests. Other effects were small or nonsignificant. Implications for basing driving recommendations on neuropsychological testing are discussed.

Older Driver Safety: A Report from the Older Drivers Project

Older driver safety is a growing public health concern for which interventions are currently being sought. Statistics show that older drivers suffer a disproportionately high rate of motor vehicle fatalities compared with other adult drivers. This disproportion is due to two factors: an increased crash rate per vehicle mile driven and an increased risk of fatality in the event of a crash. Traditionally, traffic safety efforts for the older population have focused on methods to identify unsafe drivers to enforce driving cessation, but driving cessation deprives the majority of older Americans of their primary form of transportation and has been associated with an increase in depressive symptoms. In response to these concerns, the Older Drivers Project, created by the American Medical Association in partnership with the National Highway Traffic Safety Administration, describes and advocates a more acceptable approach to traffic safety. The primary objective of this approach involves helping older drivers stay on the road safely to preserve their mobility and independence. This can be accomplished through three methods: (1) optimizing the driver, (2) optimizing the driving environment, and (3) optimizing the vehicle. In this approach, driving cessation is recommended only after the safety of the driver cannot be secured through any other means.

The role of physicians in assessing older drivers: barriers, opportunities, and strategies

BACKGROUND

Evaluation of the older driver is a difficult task for primary care physicians. We investigated the physician-perceived barriers to assessing older drivers in primary care practice.

METHODS

Twenty family physicians whose patients had completed a clinical questionnaire and neuropsychological tests participated in one of 2 focus groups. Physicians were asked about barriers to assessing older drivers in primary care and the usefulness of neuropsychological tests for assessing driving ability.

RESULTS

A number of themes emerged related to barriers in the assessment of the older driver. Major themes included concerns about being liable for the results of driving related screening and about patients reacting unfavorably to a driving assessment including cognitive tests. Physicians uniformly agreed that a protocol to guide driving assessment would be useful.

CONCLUSIONS

Physicians encounter a number of barriers to assessing older drivers but recognize the importance of driving within the context of geriatric functional assessment.

Visual dysfunction, neurodegenerative diseases, and aging

The four most common sight-threatening conditions in older adults in North America are cataract, ARM, glaucoma, and diabetic retinopathy. Even in their moderate stages, these conditions cause visual sensory impairments and reductions in health-related quality of life, including difficulties in daily tasks and psychosocial problems. Many older adults are free from these conditions, yet still experience a variety of visual perceptual problems resulting from aging-related changes in the optics of the eye and degeneration of the visual neural pathways. These problems consist of impairments in visual acuity, contrast sensitivity, color discrimination, temporal sensitivity, motion perception, peripheral visual field sensitivity, and visual processing speed. PD causes a progressive loss of dopaminergic cells predominantly in the retina and possibly in other areas of the visual system. This retinal dopamine deficiency produces selective spatial-temporal abnormalities in retinal ganglion cell function, probably arising from altered receptive field organization in the PD retina. The cortical degeneration characteristics of AD, including neurofibrillary tangles and neuritic plaques, also are present in the visual cortical areas, especially in the visual association areas. The most prominent electrophysiologic change in AD is a delay in the P2 component of the flash VEP. Deficits in higher-order visual abilities typically are compromised in AD, including problems with visual attention, perceiving structure from motion, visual memory, visual learning, reading, and object and face perception. There have been reports of a visual variant of AD in which these types of visual problems are the initial and most prominent signs of the disease. Visual sensory impairments (e.g., contrast sensitivity or achromatopsia) also have been reported but are believed more reflective of cortical disturbances than of AD-associated optic neuropathy.

Maze test performance and reported driving ability in early dementia

A battery of standard neuropsychological tests examining various features of executive function, attention, and visual perception was administered to 27 subjects with questionable to mild dementia and compared to a 4-point caregiver rating scale of driving ability. Based on the results of this study, a computerized maze task, employing 10 mazes, was administered to a second sample of 40 normal elders and questionable to moderately demented drivers. Comparison was made to the same caregiver rating scale as well as to crash frequency. In the first study of neuropsychological tests, errors on Porteus Mazes emerged as the only significant predictor of driving ability in a stepwise regression analysis. In the follow-up study employing the computerized mazes, all 10 mazes were significantly related to driving ability ratings. Computerized tests of maze performance offer promise as a screening tool to identify potential driving impairment among cognitively impaired elderly and demented drivers.

Neurologic conditions: assessing medical fitness to drive

Clinicians are often asked to make an assessment on whether a patient is medically fit to drive, even though few have been formally trained in this area. Driving is a complex task that requires having adequate operational, cognitive and higher executive functions that work together. These functions can be compromised to a greater or lesser extent in neurological disorders, such as stroke, traumatic brain injury, peripheral neuropathy, dementia, Parkinson's disease and epilepsy. There is insufficient standardized information relating to impaired function at this time. Because of this, state laws vary in their assessment of medical conditions as they relate to driver licensing. Wisconsin laws are reviewed as an example. There are numerous assessment tests for various functions, but they lack a validated correlation with actual driving performance. These and other factors, as well as practical recommendations for the practicing physicians, are the subjects of this review.