Driving Automation for Older Adults with Preclinical Alzheimer's Disease.

INTRODUCTION: Older adults with preclinical Alzheimer's disease (AD) show changes in on-road driving performance. The impact of preclinical AD on using automated vehicle (AV) technology is unknown. The aim was to evaluate safety and cognitive workload while operating AV technology in drivers with preclinical AD. INTRODUCTION: This cross-sectional study included 40 participants: 19 older adults (age 74.16 ± 4.78; MOCA scores 26.42 ± 2.52) with preclinical AD, evidenced by elevated cortical beta-amyloid; and 21 controls (age 73.81 ± 5.62; MOCA scores 28.24 ± 1.67). All participants completed two scenarios in a driving simulator. Scenario 1 included conditional automation with an emergency event that required a manual take-over maneuver. Scenario 2 was identical but with a cognitive distractor task. Emergency response time was the main safety outcome measure. Cognitive workload was calculated using moment-to-moment changes in pupillary size and converted into an Index of Cognitive Activity (ICA). Mann-Whitney U and independent t tests were used to compare group differences. RESULTS: Emergency response times were similar between drivers with preclinical AD and controls in scenario 1 (20.85 s ± 1.08 vs. 20.52 s ± 3.18; p = 0.83) and scenario 2 (14.83 s ± 7.37 vs. 13.45 s ± 10.43; p = 0.92). Likewise, no differences were found in ICA between drivers with preclinical AD and controls in scenario 1 (0.34 ± 0.08 vs. 0.33 ± 0.17; p = 0.74) or scenario 2 (0.30 ± 0.07 vs. 0.29 ± 0.17; p = 0.93). CONCLUSIONS: Older drivers with preclinical AD may safely operate AV technology, without increased response times or cognitive workload. Future on-road studies with AV technology should confirm these preliminary results in drivers with preclinical AD.

Delivering Rehabilitation Care Around the World: Voices From the Field.

OBJECTIVES: To identify the challenges and common issues that the rehabilitation health workforce experienced in delivering services in different practice settings across the world. These experiences could suggest approaches to improving rehabilitation care to people in need. DESIGN: A semi-structured interview protocol centering on 3 broad research questions was conducted to collect data. The data were analyzed to identify common themes across the cohort interviewed. SETTING: Interviews were conducted using Zoom. Interviewees not able to access Zoom provided written responses to the questions. PARTICIPANTS: Participants included 30 key rehabilitation opinion leaders from different disciplines from 24 countries, across world regions and income levels (N=30). INTERVENTIONS: NA. MAIN OUTCOME MEASURES: Although rehabilitation care deficiencies differ in severity, participants reported that the demand for services consistently outstrips available care, regardless of world region or income level. Access and social barriers, particularly in rural areas and remote regions, are common challenges for those delivering and receiving rehabilitation care. RESULTS: Individual voices from the field reported both challenges and hopeful changes in making rehabilitation services available and accessible. CONCLUSIONS: The descriptive approach undertaken has allowed individual voices, rarely included in studies, to be highlighted as meaningful data. Although the research findings are not generalizable beyond the convenience cohort included without further analysis and validation in specific local practice contexts, the authentic voices that spoke out on these issues demonstrated common themes of frustration with the current state of rehabilitation services delivery but also hopefulness that more solutions are on the horizon.

Frailty and Falls in People Living With Multiple Sclerosis.

OBJECTIVE: To explore the association between frailty and history of falls in people living with multiple sclerosis (MS). DESIGN: Secondary analysis. SETTING: University research laboratories in the United States and Israel. PARTICIPANTS: A total of 118 people (N=118) with relapsing-remitting MS (mean age, 48.9±10.0 years; 74.6% female; Expanded Disability Status Scale [EDSS] range, 1.0-6.0) were studied in this cross-sectional analysis. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: A frailty index was calculated from 40 health deficits by following standard validated procedures. The number of falls (12-month history) was recorded. RESULTS: Overall, 33.9%, 29.7%, and 36.4% of participants were classified as nonfrail, moderately frail, and severely frail, respectively. The frailty index was significantly correlated (ρ=0.37, P<.001) with higher scores on the EDSS. In univariable negative binomial regression analysis, the frailty index was associated with a higher number of falls (incidence rate ratio [IRR]=3.33; 95% CI, 1.85-5.99; P<.001). After adjustment for age, sex, and EDSS, frailty remained strongly associated with history of falls (IRR=2.78; 95% CI, 1.51-5.10; P=.001). CONCLUSIONS: The current study identifies a significant relationship between frailty and history of falls in MS, independent of age, sex, and disease severity. These findings support the notion that frailty is a syndrome related to but independent of disability in MS.

Cortical Correlates of Increased Postural Task Difficulty in Young Adults: A Combined Pupillometry and EEG Study.

The pupillary response reflects mental effort (or cognitive workload) during cognitive and/or motor tasks including standing postural control. EEG has been shown to be a non-invasive measure to assess the cortical involvement of postural control. The purpose of this study was to understand the effect of increasing postural task difficulty on the pupillary response and EEG outcomes and their relationship in young adults. Fifteen adults completed multiple trials of standing: eyes open, eyes open while performing a dual-task (auditory two-back), eyes occluded, and eyes occluded with a dual-task. Participants stood on a force plate and wore an eye tracker and 256-channel EEG cap during the conditions. The power spectrum was analyzed for absolute theta (4−7 Hz), alpha (8−13 Hz), and beta (13−30 Hz) frequency bands. Increased postural task difficulty was associated with greater pupillary response (p < 0.001) and increased posterior region alpha power (p = 0.001) and fronto-central region theta/beta power ratio (p = 0.01). Greater pupillary response correlated with lower posterior EEG alpha power during eyes-occluded standing with (r = −0.67, p = 0.01) and without (r = −0.69, p = 0.01) dual-task. A greater pupillary response was associated with lower CoP displacement in the anterior−posterior direction during dual-task eyes-occluded standing (r = −0.60, p = 0.04). The pupillary response and EEG alpha power appear to capture similar cortical processes that are increasingly utilized during progressively more challenging postural task conditions. As the pupillary response also correlated with task performance, this measurement may serve as a valuable stand-alone or adjunct tool to understand the underlying neurophysiological mechanisms of postural control.

Cognitive Testing During Mild Acute Ischemic Stroke Predicts Long-Term Return to Work.

OBJECTIVES: Many survivors of a mild ischemic stroke do not return to work or driving. Cognitive testing is commonly done to assess long-term cognitive impairment after stroke. Inpatient cognitive testing during the acute period of ischemic stroke may also be a predictor for workforce reengagement and functional outcome. MATERIALS AND METHODS: At our comprehensive stroke center, we prospectively enrolled previously working adults < 65 years old who were diagnosed with first-ever ischemic stroke, had a prestroke modified Rankin Scale (mRS) ≤ 1 and NIHSS ≤ 3. Testing performed within 1 week of stroke included the Montreal Cognitive Assessment (MOCA), Clock Drawing Test (CDT), Trail Making Tests A and B, Backward Digit Span Test, and Hospital Anxiety and Depression Scale (HADS). Other data obtained included age, gender, years of education, occupation, stroke location, stroke laterality, and presence of white matter disease on imaging. Outcome measures assessed at 3 months, 6 months, and 12 months post-stroke included return to work, return to driving, and mRS. In a logistic regression analysis, we performed both univariate and multivariate analyses. Multivariate analysis was completed on variables with p-value ≤ 0.05 in the univariate analysis. RESULTS: Of 39 total stroke patients enrolled and tested (median [IQR] age 55 [46-60] years; 77.5% male; 22.5% female), 36 completed 3-month follow up, of which 58% returned to work, 78% returned to driving, and 72% had mRS of 0-1. In multivariate analysis, a single point increase in the clock drawing task score increased the odds of return to work by 3.79 (95% CI, 1.10-14.14) and return to driving by 6.74 (95% CI, 1.22-37.23) at 3 months. MOCA and HADS were both associated with mRS ≤ 1. MOCA was associated with return to work at 6 months and CDT was associated with return to work at 12 months. CONCLUSION: Cognitive testing with CDT and MOCA in the acute period after ischemic stroke may predict common patient goals post stroke, including return to work, driving, and independence. These tools can potentially be used for prognosis and identifying those who may benefit from further interventions.

Reliability and Validity of Pupillary Response During Dual-Task Balance in Parkinson Disease.

OBJECTIVE: To investigate the reliability and validity of pupillary response during dual-task balance conditions in individuals with Parkinson disease (PD). DESIGN: Cross-sectional study. SETTING: University of Kansas Medical Center Parkinson's Disease and Movement Disorder Center. PARTICIPANTS: Participants (N=68) included individuals with PD (n=33) and healthy controls (n=35). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Pupillary response was the main outcome measure that was measured during the following conditions: single-task balance eyes open, single-task balance eyes occluded, dual-task eyes open, and dual-task eyes occluded. After each condition, the National Aeronautics and Space Administration-Task Load Index (NASA-TLX) was administered to assess self-reported cognitive workload. To examine the test-retest reliability of the pupillary response, the conditions were administered twice for each individual within 2 hours. Intraclass correlation coefficients (ICC) were used to analyze the test-retest reliability of pupillary response in each condition for both groups. Pearson's r correlation was used to assess the convergent validity of pupillary response against the NASA-TLX. RESULTS: The test-retest reliability was excellent for both groups in almost all conditions (ICC>0.75). There were no correlations between pupillary response and the NASA-TLX. However, increased mental demand (a subitem of the NASA-TLX) significantly correlated with increased pupillary response in individuals with PD (r=0.38; P=.03). CONCLUSIONS: Pupillary response showed excellent test-retest reliability and validity during dual-task balance for individuals with PD and healthy controls. Overall, these results suggest that pupillary response represents a stable index of cognitive workload during dual-task balance in individuals with PD.

Cognitive workload during verbal abstract reasoning in Parkinson's disease: a pilot study.

BACKGROUND: Pupillary response reflects cognitive workload during processing speed, working memory, and arithmetic tasks in Parkinson's disease (PD). Abstract reasoning, a higher-order cognitive function that relates different objects, events, or thoughts in a similar manner, may also be compromised in PD. The aim of this study was to compare pupillary response as a measure of cognitive workload while completing a verbal abstract reasoning test between patients with PD and age-matched controls. METHODS: Nineteen non-demented individuals with PD (66.6 ± 8.9 years) and 10 healthy controls (65.3 ± 7.3 years) were recruited. A remote eye tracker recorded the pupillary response at 60 Hz, while the participants were performing the Similarities test of Wechsler Adult Intelligence Scale-IV. Outcome measures included pupillary response, evaluated by the Index of Cognitive Activity (ICA), and behavioral responses of the Similarities test. RESULTS: The PD group (scaled scores = 8.9 ± 2.2) did not show impairment in behavioral performance on Similarities test compared with healthy controls (scaled scores = 8.8 ± 2.3; p = .91). However, the PD group (ICA = .32 ± .09) demonstrated significantly greater cognitive workload during the Similarities test compared to controls (ICA = .24 ± .08; p = .03). CONCLUSIONS: Non-demented individuals with PD exerted greater cognitive workload to complete a verbal abstract reasoning task despite similar behavioral performance compared to healthy controls. Clinical utilities of pupillary response to detect and monitor early impairment in higher-order executive function will be the subject of further study in the PD population.

Classification of Parkinson's disease and essential tremor based on balance and gait characteristics from wearable motion sensors via machine learning techniques: a data-driven approach.

BACKGROUND: Parkinson's disease (PD) and essential tremor (ET) are movement disorders that can have similar clinical characteristics including tremor and gait difficulty. These disorders can be misdiagnosed leading to delay in appropriate treatment. The aim of the study was to determine whether balance and gait variables obtained with wearable inertial motion sensors can be utilized to differentiate between PD and ET using machine learning. Additionally, we compared classification performances of several machine learning models. METHODS: This retrospective study included balance and gait variables collected during the instrumented stand and walk test from people with PD (n = 524) and with ET (n = 43). Performance of several machine learning techniques including neural networks, support vector machine, k-nearest neighbor, decision tree, random forest, and gradient boosting, were compared with a dummy model or logistic regression using F1-scores. RESULTS: Machine learning models classified PD and ET based on balance and gait characteristics better than the dummy model (F1-score = 0.48) or logistic regression (F1-score = 0.53). The highest F1-score was 0.61 of neural network, followed by 0.59 of gradient boosting, 0.56 of random forest, 0.55 of support vector machine, 0.53 of decision tree, and 0.49 of k-nearest neighbor. CONCLUSIONS: This study demonstrated the utility of machine learning models to classify different movement disorders based on balance and gait characteristics collected from wearable sensors. Future studies using a well-balanced data set are needed to confirm the potential clinical utility of machine learning models to discern between PD and ET.

Pupillary response: cognitive effort for breast cancer survivors.

PURPOSE: The purpose of this cross-sectional comparative pilot study was to evaluate cognitive effort, indexed by pupillary response (PR), for breast cancer survivors (BCS) with complaints of cognitive dysfunction following chemotherapy. STUDY AIMS: Compare the cognitive effort employed by BCS to healthy controls (HC) during neuropsychological tests (NPT) for memory, sustained attention, verbal fluency, visuospatial ability, processing speed and executive function; and Investigate the relationship between PR-indexed cognitive effort and participants' self-report of cognitive function. METHODS: Self-report of cognitive function was collected from 23 BCS and 23 HC. PR was measured during NPT. Independent two-sample t tests or Wilcoxon rank sum tests were used to compare group scores. Between-group effect size (Cohen's d) was calculated for each outcome. Correlation between mean self-report scores and PR values, as well as 95% confidence intervals, was calculated. RESULTS: No group differences were demonstrated for NPT performance. BCS reported more issues with cognitive function than HC (p < .0001). A group effect for BCS was seen with PR-indexed cognitive effort for components of most NPT (p < .05). PR was correlated with most self-report measures of cognitive function (r = 0.33-0.45). CONCLUSIONS: PR sensitivity to cognitive effort across a variety of NPT and correlation with self-report of cognitive function was demonstrated. The portability, affordability, and "real-time" aspects of PR are attractive for potential use in the clinic setting to assess cognitive function. A larger study is needed to confirm these results. Prospective investigation of PR in BCS is needed to demonstrate sensitivity to cognitive function changes over time.

Clinical Determinants of Fitness to Drive in Persons With Multiple Sclerosis: Systematic Review.

OBJECTIVE: To critically appraise the evidence for the clinical determinants of fitness to drive in adults with multiple sclerosis (MS). DATA SOURCES: The research librarian and lead author searched 7 databases for driving simulator and on-road studies for adults with MS published in the English language from 1991 to 2018. STUDY SELECTION: Three reviewers independently screened titles, abstracts, and full-texts for studies with: cohort, case-control, or cross-sectional designs; participants, 18 years or older, with relapsing or progressive MS; visual, cognitive, or motor clinical assessments as predictors; and driving performance through simulator or fitness to drive through on-road assessment as outcomes. DATA EXTRACTION: Using the 2017 American Academy of Neurology guidelines, reviewers independently classified each study from class I to class IV, or highest to lowest amount of rigor. For each clinical assessment, reviewers independently rated the level of confidence for predicting driving performance or fitness to drive from level A, highly probable; B, probable; C, possible; to level U, insufficient conclusions. DATA SYNTHESIS: Through qualitative synthesis, 2 class III and 4 class IV driving simulator studies employed 24 clinical assessments with level C (n=4) or level U (n=20) confidence for predicting driving performance. Six class II and 3 class IV on-road studies employed 35 clinical assessments with level B (n=9), level C (n=22), or level U (n=4) confidence for predicting fitness to drive. CONCLUSIONS: This systematic review identified mostly insufficient conclusions for predicting driving performance in driving simulator studies, and possible conclusions for predicting fitness to drive in on-road studies. The best available evidence suggests that the Stroke Driver Screening Assessment and Useful Field of View test probably predict fitness to drive in adults with MS (level B). Class I studies that compare predictors of fitness to drive with large prospective samples of adults with and without MS are necessary for highly probable conclusions.

The Impact of Advanced Age on Driving Safety in Adults with Medical Conditions.

BACKGROUND: Adults aged 85 and older, often referred to as the oldest-old, are the fastest-growing segment of the population. The rapidly increasing number of older adults with chronic and multiple medical conditions poses challenges regarding their driving safety. OBJECTIVE: To investigate the effect of advanced age on driving safety in drivers with medical conditions. METHODS: We categorized 3,425 drivers with preexisting medical conditions into four age groups: middle-aged (55-64 years, n = 1,386), young-old (65-74 years, n = 1,013), old-old (75-84 years, n = 803), or oldest-old (85 years and older, n = 223). All underwent a formal driving evaluation. The outcome measures included fitness to drive recommendation by the referring physician, comprehensive fitness to drive decision from an official driving evaluation center, history of motor vehicle crashes (MVCs), and history of traffic violations. RESULTS: The oldest-old reported more cardiopulmonary and visual conditions, but less neurological conditions than the old-old. Compared to the middle-aged, the oldest-old were more likely to be considered unfit to drive by the referring physicians (odds ratio [OR] = 4.47, 95% confidence interval [CI] 2.20-9.10) and by the official driving evaluation center (OR = 2.74, 95% CI 1.87-4.03). The oldest-old reported more MVCs (OR = 2.79, 95% CI 1.88-4.12) compared to the middle-aged. CONCLUSION: Advanced age adversely affected driving safety outcomes. The oldest-old are a unique age group with medical conditions known to interfere with safe driving. Driving safety strategies should particularly target the oldest-old since they are the fastest-growing group and their increased frailty is associated with severe or fatal injuries due to MVCs.

Interdisciplinary Approaches to Facilitate Return to Driving and Return to Work in Mild Stroke: A Position Paper.

Adults with mild stroke face substantial challenges resuming valued roles in the community. The term "mild" provides false representation of the lived experience for many adults with mild stroke who may continue to experience persistent challenges and unmet needs. Rehabilitation practitioners can identify and consequently intervene to facilitate improved independence, participation, and quality of life by facilitating function and reducing the burden of lost abilities among adults with mild stroke. The Health and Wellness Task Force identified 2 important, and often interdependent, goals that frequently arise among adults living with mild stroke that must be addressed to facilitate improved community reintegration: (1) return to driving and (2) return to work. Adults with mild stroke may not be receiving adequate rehabilitative services to facilitate community reintegration for several reasons but primarily because current practice models are not designed to meet such needs of this specific population. Thus, the Health and Wellness Task Force convened to review current literature and practice trends to (1) identify opportunities based on the evidence of assessment and interventions, for return to driving and return to work; and (2) identify gaps in the literature that must be addressed to take advantage of the opportunities. Based on findings, the task force proposes a new interdisciplinary practice model for adults with mild stroke who are too often discharged from the hospital to the community without needed services to enable successful return to driving and work.

Determinants of On-Road Driving in Multiple Sclerosis.

OBJECTIVE: To investigate the cognitive, visual, and motor deficits underlying poor performance on different dimensions of on-road driving in individuals with multiple sclerosis (MS). DESIGN: Prospective cross-sectional study. SETTING: MS clinic and driving simulator lab. PARTICIPANTS: Active drivers (N=102) with various types of MS. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Off-road cognitive, visual, and motor functions, as well as 13 specific driving skills. These skills were categorized into hierarchic clusters of operational, tactical, visuo-integrative, and mixed driving. Stepwise regression analysis was used to determine the off-road functions influencing performance on the on-road test and each cluster. RESULTS: Visuospatial function (P=.002), inhibition (P=.008), binocular acuity (P=.04), vertical visual field (P=.02), and stereopsis (P=.03) best determined variance in total on-road score (unadjusted R2=.37). Attentional shift (P=.0004), stereopsis (P=.007), glare recovery (P=.047), and use of assistive devices (P=.03) best predicted the operational cluster (unadjusted R2=.28). Visuospatial function (P=.002), inhibition (P=.002), reasoning (P=.003), binocular acuity (P=.04), and stereopsis (P=.005) best determined the tactical cluster (unadjusted R2=.41). The visuo-integrative model (unadjusted R2=.12) comprised binocular acuity (P=.007) and stereopsis (P=.045). Inhibition (P=.0001) and binocular acuity (P=.001) provided the best model of the mixed cluster (unadjusted R2=.25). CONCLUSIONS: Our results provide more insights into the specific impairments that influence different dimensions of on-road driving and may be used as a framework for targeted driving intervention programs in MS.

Left ventricular hypertrophy in acute stroke patients with known hypertension.

BACKGROUND: Despite effective treatments, hypertension remains uncontrolled in nearly half of the people with hypertension in the United States. Uncontrolled hypertension leads to end organ damage, such as left ventricular hypertrophy (LVH). To identify reasons for uncontrolled hypertension, we interviewed acute stroke patients with a history of hypertension and evaluated for LVH. METHODS: Using a standardized questionnaire, we collected demographic, socioeconomic, and health-care data in 300 acute ischemic and hemorrhagic stroke patients in one hospital. We also collected relevant clinical data from medical records. We analyzed factors associated with echocardiographic LVH as a marker of uncontrolled hypertension in 190 acute stroke patients with a history of hypertension. RESULTS: Overall, 46% (88/190) of patients had LVH. In univariate analysis, lower household income and self-reported poor adherence to hypertension treatment were significantly associated with increased risk of LVH. In multiple logit modeling, only poor adherence to hypertension treatment remained significantly associated with LVH, odds ratio 1.77 (95% CI: 1.01-3.11), p < 0.05. CONCLUSIONS: In acute stroke patients, poor adherence to hypertension treatment is a significant independent predictor of LVH. A clear reason for poor adherence to treatment is elusive in a large proportion of these patients in our study. Further research is needed to identify and develop strategies to combat the key factors responsible for poor adherence to hypertension treatment.

Use of a driving simulator to improve on-road driving performance and cognition in persons with Parkinson's disease: A pilot study.

BACKGROUND/AIM: The use of simulators as an assessment and intervention tool for driving is an emerging field in occupational therapy. We investigated the potential usefulness of a driving simulator to improve on-road skills and cognitive functions in drivers with Parkinson's disease (PD). METHOD: Fifteen participants with PD, and Hoehn and Yahr stages between 2 and 3 participated in this pre-post comparison study. Twelve of the 15 individuals (median age (Q1-Q3), 68 (63.5-72.5); 10 men) completed 10 hours of training in a high-fidelity driving simulator. A practical road test as well as off-road cognitive and simulator tests were administered at pre-training and post-training. RESULTS: Nine participants, who passed the road test before training, passed at post-training. Furthermore, all three participants who initially failed the on-road test passed after training. Participants' performance improved significantly from pre- to post-training on two cognitive tests: (i) the Montreal Cognitive Assessment and (ii) Dot Cancellation test. CONCLUSION: This pilot study demonstrates the potential usefulness of a simulator to improve on-road driving and driving-related cognitive skills in PD. Adequately powered randomized controlled trials are needed to further expand this field of study.

Agreement Between Physician's Recommendation and Fitness-to-Drive Decision in Multiple Sclerosis.

OBJECTIVE: To investigate the agreement of fitness-to-drive decisions made by the referring physicians and by the on-road assessors in individuals with multiple sclerosis (MS). DESIGN: Retrospective analysis. SETTING: Driving institute. PARTICIPANTS: A sample of individuals with MS (N=218) who completed the medical and driving questionnaire and performed an official on-road test. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Fitness-to-drive decision made by the on-road assessor. RESULTS: The referring physician and on-road assessor agreed on fitness to drive in 191 (88%) of the cases (prevalence-adjusted and bias-adjusted κ=.81, P<.0001). When compared with the on-road assessor's judgment, the physician's recommendation of fitness to drive was overestimated in 16 individuals with MS and underestimated in 11 individuals with MS. Patients with poor binocular acuity were more likely to be inaccurately classified by the physician (P=.001). CONCLUSIONS: This study showed a high level of agreement between the fitness-to-drive decisions made by the physicians and the on-road assessors in individuals with MS. Visual functions should be assessed in the doctor's office for more accurate referrals.

Association between site of lesion and driving performance after ischemic stroke.

BACKGROUND: Stroke presents with heterogeneous recovery periods, severity, and manifestation of deficits, all of which may adversely impact fitness-to-drive. Little is known about the association between site of lesion and driving performance after stroke. OBJECTIVE: To investigate the association between site of stroke lesion and driving performance. METHOD: Seventy-three participants (age = 56 ± 11 years; 66 men) underwent a detailed battery of visual, cognitive, and on-road tests to determine fitness-to-drive at about 10 months after ischemic stroke. Associations between stroke location and driving performance were calculated using rank biserial (r rb) correlation coefficients. Correlations were considered weak below 0.10, moderate between 0.10 and 0.49, and strong above 0.50. Wilcoxon rank sum tests were employed to discern differences in on-road driving performance between participants whose performance was of concern to the driving assessor and those who exhibited no major difficulties on the road. RESULTS: In all, 28 (38%) out of the 73 participants exhibited major difficulties on the road. Those who showed difficulties on the road performed worse in all driving skills (P < 0.05). Correlation analysis showed moderate to strong correlations between site of lesion and performance in several visual, cognitive and on-road tests. Lesions in the parietal lobe showed correlations ranging between 0.23 and 0.25 with driving skills including vehicle control and speed adaptations. Lesions in the occipital lobes correlated strongly with visual field (r rb = 0.53) and moderately with visual neglect (r rb = 0.28). CONCLUSIONS: Our results suggest that cortical lesions in the parietal and occipital lobes are associated with driving deficits after stroke. Further advances in our understanding of the neural correlates of driving performance may provide prognostic markers of fitness-to-drive and lead to early, targeted rehabilitation.

On-road driving impairments and associated cognitive deficits after stroke.

BACKGROUND: Little is known about the critical on-road driving skills that get affected after a stroke. The purpose of this study was to investigate the key on-road driving impairments and their associated cognitive deficits after a stroke. A second aim was to investigate if lateralization of stroke impacts results of the cognitive and on-road driving tests. METHODS: In this cross-sectional study, 99 participants with a first-ever stroke who were actively driving prior to stroke underwent a cognitive battery and a standardized road test that evaluated 13 specific on-road driving skills. These on-road driving skills were mapped onto an existing, theoretical framework that categorized the on-road items into hierarchic clusters of operational, tactical, visuo-integrative, and mixed driving skills. The total score on the road test and the on-road decision, made by a certified fitness-to-drive expert, decided the main outcome. The critical on-road driving skills predicting the on-road decision were identified using logistic regression analysis. Linear regression analysis was employed to determine the cognitive impairments leading to poor total on-road scores. Analyses were repeated for right- and left-sided strokes. RESULTS: In all, 37 persons scored poorly on the road test. These participants performed worse in all hierarchic clusters of on-road driving. Performances on the operational cluster and the visuo-integrative cluster best predicted on-road decisions (R(2) = 0.60). 'Lane changing' and 'understanding, insight, and quality of traffic participation' were the critical skill deficits leading to poor performance on the road test (R(2) = 0.65). Divided attention was the main determinant of on-road scores in the total group (R(2) = 0.06). Participants with right-sided stroke performed worse on visual field, visual neglect, visual scanning, visuo-constructive skills, and divided attention compared with those with left-sided stroke. Divided attention was the main determinant of total on-road scores in the right-sided stroke group (R(2) = 0.10). A combination of visual scanning, speed of processing, and executive dysfunction yielded the best model to predict on-road scores in left-sided strokes (R(2) = 0.46). CONCLUSIONS: Poor performance in the road test after stroke is determined by critical operational and visuo-integrative driving impairments. Specific and different driving evaluation and training programs are needed for right- and left-sided strokes.