The objective was to compare a standardized road test to naturalistic driving by older people who may have cognitive impairment to define improvements that could potentially enhance the validity of road testing in this population.
Road testing has been widely adapted as a tool to assess driving competence of older people who may be at risk for unsafe driving because of dementia; however, the validity of this approach has not been rigorously evaluated.
For 2 weeks, 80 older drivers (38 healthy elders and 42 with cognitive impairment) who passed a standardized road test were video recorded in their own vehicles. Using a standardized rating scale, 4 hr of video was rated by a driving instructor. The authors examine weighting of individual road test items to form global impressions and to compare road test and naturalistic driving using factor analyses of these two assessments.
The road test score was unidimensional, reflecting a major factor related to awareness of signage and traffic behavior. Naturalistic driving reflected two factors related to lane keeping as well as traffic behavior.
Maintenance of proper lane is an important dimension of driving safety that appears to be relatively underemphasized during the highly supervised procedures of the standardized road test.
Road testing in this population could be improved by standardized designs that emphasize lane keeping and that include self-directed driving. Additional information should be sought from observers in the community as well as crash evidence when advising older drivers who may be cognitively impaired.
driving; aging; dementia; Alzheimer’s disease; cognitive impairment
The goal of this study was to define the natural progression of driving impairment in persons who initially have very mild to mild dementia.
We studied 128 older drivers, including 84 with early Alzheimer’s disease (AD) and 44 age-matched control subjects without cognitive impairment. Subjects underwent repeated assessments of their cognitive, neurological, visual and physical function over three years. Self-reports of driving accidents and traffic violations were supplemented by reports from family informants and state records. Within two weeks of the office evaluation, subjects were examined by a professional driving instructor on a standardized road test.
At baseline, AD subjects 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 AD subjects 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.
This study confirms previous reports of potentially hazardous driving in persons with early AD, but also indicates that some individuals with very mild dementia can continue to drive safely for extended periods of time. Regular followup assessments, however, are warranted in those individuals.
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.
driving; dementia; mild cognitive impairment; maze; computerized assessment
Single photon emission computed tomography (SPECT) was used in this study to examine the neurophysiologic basis of driving impairment in 79 subjects with dementia. Driving impairment, as measured by caregiver ratings, was significantly related to regional reduction of right hemisphere cortical perfusion on SPECT, particularly in the temporo-occipital area. With increased severity of driving impairment, frontal cortical perfusion was also reduced. Clock drawing was more significantly related to driving impairment than the Mini-Mental State Examination. Driving impairment in Alzheimer's disease is related to changes in cortical function which vary according to severity of disease. Cognitive tests of visuoperceptual and executive functions may be more useful screening tools for identifying those at greatest risk for driving problems than examinations like the Mini-Mental State Examination, that are weighted toward left hemisphere based verbal tasks.
SPECT; driving; Alzheimer's disease; 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.
driving; dementia; Alzheimer’s disease; neuropsychology; cognition
Better tools for assessing cognitive impairment in the early stages of Alzheimer’s disease (AD) are required to enable diagnosis of the disease before substantial neurodegeneration has taken place and to allow detection of subtle changes in the early stages of progression of the disease. The National Institute on Aging and the Alzheimer’s Association convened a meeting to discuss state of the art methods for cognitive assessment, including computerized batteries, as well as new approaches in the pipeline. Speakers described research using novel tests of object recognition, spatial navigation, attentional control, semantic memory, semantic interference, prospective memory, false memory and executive function as among the tools that could provide earlier identification of individuals with AD. In addition to early detection, there is a need for assessments that reflect real-world situations in order to better assess functional disability. It is especially important to develop assessment tools that are useful in ethnically, culturally and linguistically diverse populations as well as in individuals with neurodegenerative disease other than AD.
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.
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.
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.
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.
Alzheimer’s disease; Driving; Road test; Anxiety; Visual analog mood scales
To determine the validity and reliability of clinician ratings of the driving competence of patients with mild dementia.
Observational study of a cross-section of drivers with mild dementia based on chart review by clinicians with varying types of expertise and experience.
Outpatient dementia clinic.
Fifty dementia subjects from a longitudinal study of driving and dementia.
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.
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.
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.
dementia; driving; Alzheimer’s disease
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.
Participants were recruited from the neurology department of a community hospital affiliated with Brown Medical School.
Participants included 75 older adults (17 with mild AD, 33 with very mild AD, and 25 elderly controls).
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.
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.
An experienced neurologist’s assessment of driving competence may be a valid predictor of driving performance of patients with early AD.
dementia; driving; assessment; 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.
Dementia; Motor vehicles; Cognition; Memory; Neurodegenerative diseases; Basal ganglia
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.
dementia; driving; competence; impairment
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.
Driving; Aging; Dementia; Neuropsychology; Attention; Visual
We conducted a combined observational cohort and case-control study in patients with Alzheimer’s disease (AD) to assess the effects of acetylcholinesterase inhibitor (ChEI) treatment on cognitive functions important for driving.
Performance of twenty-four outpatients with newly diagnosed (untreated) early stage AD was compared prior to beginning ChEI (Pre-ChEI) and after 3 months of therapy (Post-ChEI) on a set of computerized tests of visual attention and executive function administered under both single-task and dual-task conditions. In order to address the limitation of a lack of an untreated control group in this observational cohort study, performance of thirty-five outpatients with newly diagnosed (untreated) early stage AD (ChEI Non-Users) were also compared to a demographically-matched group of AD patients treated with stable doses of a ChEI (ChEI Users) on these tasks.
Performance was consistently worse under dual-task than single-task conditions regardless of ChEI treatment status. However, ChEI treatment consistently affected specific components of attention within each test across both sets of comparisons: ChEI treatment enhanced simulated driving accuracy, and was associated with significantly better visual search target detection accuracy and response time in both Pre/Post ChEI and Users/Non-Users treatment comparisons. ChEI treatment also improved overall time to complete a set of mazes while not affecting accuracy of completion.
ChEI treatment was associated with improvements in tests of executive function and visual attention. These findings could have important implications for patients who continue to drive in the early stages of AD.
All cognitive disorders/dementia; Alzheimer’s disease; Cholinesterase inhibitors; Attention; Driving
The present study examined if knowledge of driving laws independently predicts on-the-road driving performance among cognitively impaired older adults.
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.
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).
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.
Cognitive impairment; Driving performance; Driving license; Road traffic; Knowledge of driving laws
Patients with amnestic mild cognitive impairment (MCI) demonstrate decline in everyday function. In this study, we investigated whether whole brain atrophy and apolipoprotein E (APOE) genotype are associated with the rate of functional decline in MCI.
Participants were 164 healthy controls, 258 MCI patients, and 103 patients with mild Alzheimer’s disease (AD), enrolled in the Alzheimer’s Disease Neuroimaging Initiative (ADNI). They underwent brain MRI scans, APOE genotyping, and completed up to 6 biannual Functional Activities Questionnaire (FAQ) assessments. Random effects regressions were used to examine trajectories of decline in FAQ across diagnostic groups, and to test the effects of ventricle-to-brain ratio (VBR) and APOE genotype on FAQ decline among MCI patients.
Rate of decline in FAQ among MCI patients was intermediate between that of controls and mild AD patients. Patients with MCI who converted to mild AD declined faster than those who remained stable. Among MCI patients, increased VBR and possession of any APOE ε4 allele were associated with faster rate of decline in FAQ. In addition, there was a significant VBR by APOE ε4 interaction such that patients who were APOE ε4 positive and had increased atrophy experienced the fastest decline in FAQ.
Functional decline occurs in MCI, particularly among patients who progress to mild AD. Brain atrophy and APOE ε4 positivity are associated with such declines, and patients who have elevated brain atrophy and are APOE ε4 positive are at greatest risk of functional degradation. These findings highlight the value of genetic and volumetric MRI information as predictors of functional decline, and thus disease progression, in MCI.
MRI; Brain atrophy; APOE ε4; activities of daily living; MCI
Given previous demonstrations of both selective and divided attention deficits in Alzheimer’s disease (AD) patients, understanding how declines in the integrity of component processes of selective attention in these patients interact with impairments to executive processes mediating dual-task performance has both theoretical and practical relevance. To address this issue, healthy elderly and AD patients performed computerized tasks of spatial orienting, Simon response interference, and visual search both in isolation and while simultaneously engaged in a visuomotor tracking task (i.e., maintaining car position within a simulated driving environment). Results from the single-task conditions confirmed previous demonstrations of selective attention deficits in AD. Dual-task conditions produced in AD patients (but not healthy elderly) a change in the efficiency of the selective attention mechanisms themselves, as reflected in differential effects on cue or display conditions within each task. Rather than exacerbating the selective attention deficits observed under single-task conditions, however, dual-task conditions produced an apparent diminution of these deficits. We suggest this diminution is due to the combination of deficient top-down inhibitory processes along with a decrease in the attention-capturing properties of cue information under dual-task conditions in AD patients. These findings not only increase our understanding of the nature of the attentional deficits in AD patients, but also have implications for understanding the processes mediating attention in neurologically intact individuals.
divided attention; dementia; executive control; spatial orienting; visual search; response interference
Although automobiles remain the transportation of choice for older adults, late life cognitive impairment and dementia often impair the ability to drive safely. There is, however, no commonly utilized 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 upon by patients, their families, other health professionals, and often the Department of Motor Vehicles (DMV) to assess their patients' fitness-to-drive and to make recommendations about driving privileges. Using the case of Mr W, we describe the challenges of driving with cognitive impairment for both the patient and caregiver, summarize the literature on dementia and driving, discuss evidenced-based assessment of fitness-to-drive, and address important ethical and legal issues. We describe the role of physician assessment, referral to neuropsychology, functional screens, dementia severity tools, driving evaluation clinics, and DMV referrals that may assist with evaluation. Finally, we discuss mobility counseling (eg, exploration of transportation alternatives) since 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 our patients' social connectedness and quality of life, while meeting their psychological and medical needs and maintaining personal and public safety.
The frequent co-occurrence of Alzheimer disease (AD) pathology in patients with normal pressure hydrocephalus suggests a possible link between ventricular dilation and AD. If enlarging ventricles serve as a marker of faulty cerebrospinal fluid (CSF) clearance mechanisms, then a relationship may be demonstrable between increasing ventricular volume and decreasing levels of amyloid beta peptide (Aβ) in CSF in preclinical and early AD. CSF biomarker data (Aβ, tau, and phosphorylated tau) as well as direct measurements of whole brain and ventricular volumes were obtained from the Alzheimer's Disease Neuroimaging Initiative dataset. The ratio of ventricular volume to whole brain volume was derived as a secondary independent measure. Baseline data were used for the group analyses of 288 subjects classified as being either normal (n=87), having the syndrome of mild cognitive impairment (n=136), or mild AD (n=65). Linear regression models were derived for each biomarker as the dependent variable, using the MRI volume measures and age as independent variables. For controls, ventricular volume was negatively associated with CSF Aβ in APOE ε4 positive subjects. A different pattern was seen in AD subjects, in whom ventricular volume was negatively associated with tau, but not Aβ in ε4 positive subjects. Increased ventricular volume may be associated with decreased levels of CSF Aβ in preclinical AD. The basis for the apparent effect of APOE ε4 genotype on the relationship of ventricular volume to Aβ and tau levels is unknown, but could involve altered CSF-blood-brain barrier function during the course of disease.
Alzheimer's; MRI; cerebrospinal fluid; A-beta
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.
Alzheimer’s disease; cognition; dementia; driving; perception
Over the past 10 years, several instruments developed specifically for the assessment of Quality of Life (QOL) in dementia have been introduced. The goal of the current review is to present, compare, and critique existing QOL measures for dementia populations to assist investigators and clinicians in selecting the optimal inventory for their specific needs. Nine measures are reviewed with a focus on conceptualizations of QOL, psychometric data, targeted patient population, and administration and scoring procedures. Critical discussion and comparison of the instruments is presented after the scales are described individually. Differences in definitions of QOL, assessment procedures, and methods that were used to establish the validity of instruments are highlighted. An important direction for future research on QOL scales for dementia is to establish their responsiveness to change over time. It will also be important to identify factors that affect reports of QOL, determine the how perceived QOL affects decisions regarding the care of dementia patients, and evaluate interventions to increase patient QOL.
To develop a cognitive and functional screening battery for the on-road performance of older drivers with dementia.
A prospective observational study.
On-road driving evaluation clinic at an academic rehabilitation center
Ninety-nine older people with dementia (63% male, mean age = 74.2 years, SD= 9), referred by community physicians to an Occupational Therapy driving clinic.
The outcome variable was pass/fail on the modified Washington University Road Test. Predictor measures were tests of visual, motor and cognitive functioning, selected for their empirical or conceptual relationship to the complex task of driving safely.
Sixty-five (65%) of participants failed the on-road driving test. The best predictive model, with an overall accuracy of up to 85% when participants were blinded, included AD-8 score, the Clock Drawing Test score, and the time to complete either the Snellgrove Maze Test (SMT) or Trail Making Test A. Visual and motor functioning were not associated with road driving test failure.
A screening battery that could be performed in less than 10 minutes predicted with good accuracy a failure rating on the on-road driving test in this sample of older drivers with dementia. A “probability of failure” calculator is provided from a logistic regression model that may be useful for clinicians in their decision to refer impaired older adults for further testing. More studies are needed in larger community based samples, along with discussions with patients, families and clinicians, in regards to acceptable levels of test uncertainty.
on-road driving safety; dementia; older drivers