Driving impairment and crash risk in Parkinson disease: A systematic review and meta-analysis

Effectiveness of a time to fixate for fitness to drive evaluation in neurological patients

We present a method to automatically calculate time to fixate (TTF) from the eye-tracker data in subjects with neurological impairment using a driving simulator. TTF presents the time interval for a person to notice the stimulus from its first occurrence. Precisely, we measured the time since the children started to cross the street until the drivers directed their look to the children. From 108 neurological patients recruited for the study, the analysis of TTF was performed in 56 patients to assess fit-, unfit-, and conditionally-fit-to-drive patients. The results showed that the proposed method based on the YOLO (you only look once) object detector is efficient for computing TTFs from the eye-tracker data. We obtained discriminative results for fit-to-drive patients by application of Tukey's honest significant difference post hoc test (p < 0.01), while no difference was observed between conditionally-fit and unfit-to-drive groups (p = 0.542). Moreover, we show that time-to-collision (TTC), initial gaze distance (IGD) from pedestrians, and speed at the hazard onset did not influence the result, while the only significant interaction is among fitness, IGD, and TTC on TTF. Obtained TTFs are also compared with the perception response times (PRT) calculated independently from eye-tracker data and YOLO. Although we reached statistically significant results that speak in favor of possible method application for assessment of fitness to drive, we provide detailed directions for future driving simulation-based evaluation and propose processing workflow to secure reliable TTF calculation and its possible application in for example psychology and neuroscience.

Parkinson's Disease and Driving Fitness: A Systematic Review of the Existing Guidelines

BACKGROUND

Motor/nonmotor symptomatology and antiparkinsonian drugs deteriorate the driving ability of Parkinson's disease (PD) patients.

OBJECTIVES

Treating neurologists are frequently asked to evaluate driving fitness of their patients and provide evidence-based consultation. Although several guidelines have been published, the exact procedure along with the neurologist's role in this procedure remains obscure.

METHODS

We systematically reviewed the existing guidelines, regarding driving fitness evaluation of PD patients. We searched MEDLINE and Google Scholar and identified 109 articles. After specified inclusion criteria were applied, 15 articles were included (nine national guidelines, five recommendation papers, and one consensus statement).

RESULTS

The treating physician is proposed as the initial evaluator in 8 of 15 articles (neurologist in 2 articles) and may refer patients for a second-line evaluation. The evaluation should include motor, cognitive, and visual assessment (proposed in 15, 13, and 8 articles, respectively). Specific motor tests are proposed in eight articles (cutoff values in four), whereas specific neuropsychological and visual tests are proposed in seven articles each (cutoff values in four and three articles, respectively). Conditional licenses are proposed in 11 of 15 articles, to facilitate driving for PD patients. We summarized our findings on a graphic of the procedure for driving fitness evaluation of PD patients.

CONCLUSIONS

Neurological aspects of driving fitness evaluation of PD patients are recognized in most of the guidelines. Motor, neuropsychological, visual, and sleep assessment and medication review are key components. Clear-cut instructions regarding motor, neuropsychological, and visual tests and relative cutoff values are lacking. Conditional licenses and periodical reevaluation of driving fitness are important safety measures.

Digital driving data can track driving exposure and quality of life in Parkinson's disease

OBJECTIVE

Parkinson's disease (PD) impairs motor and non-motor functions. Driver strategies to compensate for impairments, like avoiding driving in risky environments, may reduce on-road risk at the cost of decreasing driver mobility, independence, and quality of life (QoL). It is unclear how PD symptoms link to driving risk exposure, strategies, and QoL. We assessed associations between PD symptoms and driving exposure (1) overall, (2) in risky driving environments, and (3) in relationship to QoL.

METHODS

Twenty-eight drivers with idiopathic PD were assessed using the Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and RAND 36-Item Short Form Health Survey (SF-36). Real-world driving was monitored for 1 month. Overall driving exposure (miles driven) and risky driving exposure (miles driven in higher risk driving environments) were assessed across PD symptom severity. High traffic, night, and interstate roads were considered risky environments.

RESULTS

18,642 miles (30,001 km) driven were collected. Drivers with PD with worse motor symptoms (MDS-UPDRS Part III) drove more overall (b = 0.17, P < .001) but less in risky environments (night: b = -0.35, P < .001; interstate roads: b = -0.23, P < .001; high traffic: b = -0.14, P < .001). Worse non-motor daily activities symptoms (MDS-UPDRS Part I) did not affect overall driving exposure (b = -0.05, P = .43) but did affect risky driving exposure. Worse non-motor daily activities increased risk exposure to interstate (b = 0.36, P < .001) and high traffic (b = 0.09, P = .03) roads while reducing nighttime risk exposure (b = -0.15, P = .01). Daily activity impacts from motor symptoms (MDS-UPDRS Part II) did not affect distance driven. Reduced driving exposure (number of drives per day) was associated with worse physical health-related QoL (b = 2.87, P = .04).

CONCLUSIONS

Results provide pilot data revealing specific PD symptom impacts on driving risk exposure and QoL. Drivers with worse non-motor impairments may have greater risk exposure. In contrast, drivers with worse motor impairments may have reduced driver risk exposure. Reduced driving exposure may worsen physical health-related QoL. Results show promise for using driving to inform clinical care.

Does in-vehicle automation help individuals with Parkinson's disease? A preliminary analysis

Introduction

PD is a progressive neurodegenerative disorder that affects, according to the ICF, body systems (cognitive, visual, and motor), and functions (e.g., decreased executive functions, decreased visual acuity, impaired contrast sensitivity, decreased coordination)-all which impact driving performance, an instrumental activity of daily living in the domain of "Activity" and "Participation" according to the ICF. Although there is strong evidence of impaired driving performance in PD, few studies have explored the real-world benefits of in-vehicle automation technologies, such as in-vehicle information systems (IVIS) and advanced driver assistance systems (ADAS), for drivers with PD. These technologies hold potential to alleviate driving impairments, reduce errors, and improve overall performance, allowing individuals with PD to maintain their mobility and independence more safely and for longer periods. This preliminary study aimed to fill the gap in the literature by examining the impact of IVIS and ADAS on driving safety, as indicated by the number of driving errors made by people with PD in an on-road study.

Methods

Forty-five adults with diagnosed PD drove a 2019 Toyota Camry equipped with IVIS and ADAS features (Toyota Safety Sense 2.0) on a route containing highway and suburban roads. Participants drove half of the route with the IVIS and ADAS systems activated and the other half with the systems deactivated.

Results

The results suggest that systems that assume control of the driving task, such as adaptive cruise control, were most effective in reducing driving errors. Furthermore, individual differences in cognitive abilities, particularly memory, were significantly correlated with the total number of driving errors when the systems were deactivated, but no significant correlations were present when the systems were activated. Physical capability factors, such as rigidity and bradykinesia, were not significantly correlated with driving error.

Discussion

Taken together, these results show that in-vehicle driver automation systems can benefit drivers with PD and diminish the impact of individual differences in driver cognitive ability.

Medication and Road Test Performance Among Cognitively Healthy Older Adults

Importance

Older adults are increasingly prescribed medications that have adverse effects. Prior studies have found a higher risk of motor vehicle crashes to be associated with certain medication use.

Objective

To determine whether specific medication classes were associated with performance decline as assessed by a standardized road test in a community sample of cognitively healthy older adults, to evaluate additional associations of poor road test performance with comorbid medical conditions and demographic characteristics, and to test the hypothesis that specific medication classes (ie, antidepressants, benzodiazepines, sedatives or hypnotics, anticholinergics, antihistamines, and nonsteroidal anti-inflammatory drugs or acetaminophen) would be associated with an increase in risk of impaired driving performance over time.

Design, Setting, and Participants

This was a prospective cohort study of 198 cognitively healthy adults 65 years and older with a valid driver's license who were followed up annually, with rolling enrollment. Data were collected from participants in St Louis, Missouri, and neighboring Illinois who were enrolled in the Knight Alzheimer's Disease Research Center. Data were collected from August 28, 2012, to March 14, 2023, and analyzed from April 1 to 25, 2023. Participants with healthy cognition, defined as a Clinical Dementia Rating score of 0 at baseline and subsequent visits, who had available clinical, neuropsychological, road tests, and self-reported medication data were included.

Exposure

Potentially driver-impairing medication use.

Main Outcomes and Measures

The primary outcome measure was performance on the Washington University Road Test (pass or marginal/fail). Multivariable Cox proportional hazards models were used to evaluate associations between potentially driver-impairing medication use and road test performance.

Results

Of the 198 included adults (mean [SD] baseline age, 72.6 [4.6] years; 87 female [43.9%]), 70 (35%) received a marginal/fail rating on the road test over a mean (SD) follow-up of 5.70 (2.45) years. Any use of antidepressants (adjusted hazard ratio [aHR], 2.68; 95% CI, 1.69-4.71), serotonin and norepinephrine reuptake inhibitors (aHR, 2.68; 95% CI, 1.54-4.64), sedatives or hypnotics (aHR, 2.70; 95% CI, 1.40-5.19), or nonsteroidal anti-inflammatory drugs (aHR, 2.72; 95% CI, 1.31-5.63) was associated with an increase in risk of receiving a marginal/fail rating on the road test compared with control individuals. Conversely, participants taking lipid-lowering agents had a lower risk of receiving a marginal/fail rating compared to control individuals. There were no statistically significant associations found between anticholinergic or antihistamines and poor performance.

Conclusions and Relevance

In this prospective cohort study, specific medication classes were associated with an increase in risk of poor road test performance over time. Clinicians should consider this information and counsel patients accordingly when prescribing these medications.

Real-World Driving Data Indexes Dopaminergic Treatment Effects in Parkinson's Disease

Background

Driving is a complex, everyday task that impacts patient agency, safety, mobility, social connections, and quality of life. Digital tools can provide comprehensive real-world (RW) data on driver behavior in patients with Parkinson's disease (PD), providing critical data on disease status and treatment efficacy in the patient's own environment.

Objective

This pilot study examined the use of driving data as a RW digital biomarker of PD symptom severity and dopaminergic therapy effectiveness.

Methods

Naturalistic driving data (3974 drives) were collected for 1 month from 30 idiopathic PD drivers treated with dopaminergic medications. Prescriptions data were used to calculate levodopa equivalent daily dose (LEDD). The association between LEDD and driver mobility (number of drives) was assessed across PD severity, measured by the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS).

Results

PD drivers with worse motor symptoms based on self-report (Part II: P = 0.02) and clinical examination (Part III: P < 0.001) showed greater decrements in driver mobility. LEDD levels >400 mg/day were associated with higher driver mobility than those with worse PD symptoms (Part I: P = 0.02, Part II: P < 0.001, Part III: P < 0.001).

Conclusions

Results suggest that comprehensive RW driving data on PD patients may index disease status and treatment effectiveness to improve patient symptoms, safety, mobility, and independence. Higher dopaminergic treatment may enhance safe driver mobility in PD patients with worse symptom severity.

Factors Influencing Driving following DBS Surgery in Parkinson's Disease: A Single UK Centre Experience and Review of the Literature

Parkinson's disease (PD) is a complex neurodegenerative disorder, leading to impairment of various neurological faculties, including motor, planning, cognitivity, and executive functions. Motor- and non-motor symptoms of the disease may intensify a patient's restrictions to performing usual tasks of daily living, including driving. Deep Brain Stimulation (DBS) associated with optimized clinical treatment has been shown to improve quality of life, motor, and non-motor symptoms in PD. In most countries, there are no specific guidelines concerning minimum safety requirements and the timing of return to driving following DBS, leaving to the medical staff of individual DBS centres the responsibility to draw recommendations individually regarding patients' ability to drive after surgery. The aim of this study was to evaluate factors that might influence the ability to drive following DBS in the management of PD. A total of 125 patients were included. Clinical, epidemiological, neuropsychological, and surgical factors were evaluated. The mean follow-up time was 129.9 months. DBS improved motor and non-motor symptoms of PD. However, in general, patients were 2.8-fold less likely to drive in the postoperative period than prior to surgery. Among the PD characteristics, patients with the akinetic subtype presented a higher risk to lose their driving licence postoperatively. Furthermore, the presence of an abnormal postoperative neuropsychological evaluation was also associated with driving restriction following surgery. Our data indicate that restriction to drive following surgery seems to be multifactorial rather than a direct consequence of DBS itself. Our study sheds light on the urgent need for a standardised multidisciplinary postoperative evaluation to assess patients' ability to drive following DBS.

Parkinson's disease affects gaze behaviour and performance of drivers

The aim of this study was to investigate the effects of PD and ageing on gaze behaviour and performance of drivers in a simulated task. Ten drivers with PD, ten neurologically healthy older drivers, and ten neurologically healthy younger adult drivers were asked to drive in a car simulator for three minutes, maintaining car speed between 100 and 120 km/h and avoiding collisions. Driver's eye movements were recorded. Drivers with PD had more collisions and spent less time driving within the speed zone than the younger-drivers. Drivers with PD performed an increased number of fixations towards task-irrelevant areas of the visual scene and higher visual entropy, indicating a more random gaze behaviour. Older drivers restricted their visual search to the lane area in order to detect threat-related stimuli. PD led to drops in performance of drivers in the car simulator. Practitioner summary: Parkinson's disease (PD) and ageing process caused a drop in driving performance. Drivers with PD made fewer fixations on task-relevant information and showed higher visual entropy than young adults. Older drivers restricted their visual search to the lane than other areas of interest.

Association Between Young-Onset Dementia and Risk of Hospitalization for Motor Vehicle Crash Injury in Taiwan

IMPORTANCE

Several studies have suggested that older-onset dementia is associated with an increased risk of motor vehicle crash injury (MVCI). However, evidence of an association between young-onset dementia and the risk of MVCI is insufficient, particularly in Asia.

OBJECTIVE

To investigate the association between young-onset dementia and MVCI-related hospitalization in Taiwan.

DESIGN, SETTING, AND PARTICIPANTS

In this nationwide, population-based cohort study in Taiwan, a cohort of 39 344 patients aged 40 to 64 years with incident dementia diagnosed between 2006 and 2012 was matched 1:1 with a cohort of participants without dementia by age, sex, and index year (initial diagnosis of dementia). Participants were identified from Taiwan's National Health Insurance Research Database (NHIRD). Data were analyzed between March 25 and October 22, 2021.

EXPOSURES

Dementia, defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes.

MAIN OUTCOMES AND MEASURES

Hospitalization for MVCI, determined using linked data from Taiwan's Police-Reported Traffic Accident Registry and the NHIRD from January 1, 2003, to December 31, 2015. Hazard ratios (HRs) for MVCI-related hospitalization were estimated using Cox proportional hazards regression models adjusted for sex, age, salary-based insurance premium, urbanization level, and comorbidities.

RESULTS

Of the 78 688 participants, 47 034 (59.8%) were male; the mean (SD) age was 54.5 (7.4) years. During the 10-year follow-up period, the incidence density of MVCI-related hospitalization was 45.58 per 10 000 person-years (95% CI, 42.77-48.39 per 10 000 person-years) among participants with dementia and 24.10 per 10 000 person-years (95% CI, 22.22-25.99 per 10 000 person-years) among participants without dementia. Compared with participants without dementia, patients with young-onset dementia were at higher risk of MVCI-related hospitalization (adjusted HR [aHR], 1.83; 95% CI, 1.63-2.06), especially those in younger age groups (aged 40-44 years: aHR, 3.54; 95% CI, 2.48-5.07) and within a shorter period (within 1 year of follow-up: aHR, 3.53; 95% CI, 2.50-4.98) after dementia was diagnosed. Patients with young-onset dementia also had a higher risk of being a pedestrian when the crash occurred (aHR, 2.89; 95% CI, 2.04-4.11), having an intracranial or internal injury (aHR, 2.44; 95% CI, 2.02-2.94), and having a severe injury (aHR, 2.90; 95% CI, 2.16-3.89).

CONCLUSIONS AND RELEVANCE

In this retrospective cohort study, patients in Taiwan with a diagnosis of young-onset dementia had a higher risk of MVCI-related hospitalization than did individuals without dementia and the risk varied by age, disease duration, transport mode, injury type, and injury severity. These findings suggest a need for the planning of strategies to prevent transportation crashes among patients with young-onset dementia.

Clinical Factors Predicting Voluntary Driving Cessation among Patients with Parkinson’s Disease

Factors that influence the decision of voluntary driving cessation in patients living with Parkinson’s disease (PD) are still unclear. We aimed to reveal the factors affecting the decision of voluntary driving cessation in patients with PD. This hospital-based cross-sectional study recruited consecutive outpatients with PD. Data on sociodemographic and clinical characteristics and medication use were collected from the patients using semistructured interviews. Cognitive function was evaluated using the Japanese version of the Montreal Cognitive Assessment (MoCA-J). We excluded patients with dementia or motor impairment ( $\text{Hoehn}-\text{Yahr}\text{stage}>3$ ). We divided the patients into two groups, with and without voluntary driving cessation (D: driver; RD: retired driver), and conducted investigations using multivariate logistic regression analyses. Of the 40 patients, 8 (20.0%) voluntarily retired from driving. Patients who decided on driving cessation had a higher prevalence of freezing of gait (FOG) (D vs. RD, 25.0% vs. 87.5%; $P=0.001$ ) and tended to have lower scores for attention in the MoCA-J (D vs. RD, $5.0\pm 1.2$ vs. $4.1\pm 1.4$ ; $P=0.086$ ). Multivariable analysis showed that FOG was independently associated with driving cessation (odds ratio: 14.46, 95% confidence interval: 1.91–303.74). FOG was associated with voluntary driving cessation in patients with PD without dementia or severe motor impairment. Physicians should consider providing extensive social support to maintain patients’ mobility and independence, especially if the patients have these clinical factors.

Tourette Syndrome and Driving

BACKGROUND

Driving ability may be impaired in patients with various movement disorders, but it has not been studied in patients with Tourette syndrome (TS).

CASES

We describe a series of 6 patients from our large cohort of TS patients followed in our movement disorders clinic in whom severe tics have had interfered with their driving abilities. The motor tics involved facial muscles and caused visual impairment because of frequent blinking and transient blepharospasm (dystonic tic), but complex limb and truncal tics also seriously impacted their driving.

CONCLUSIONS

Although majority of patients with TS have no functional impairment, severe motor tics in some patients may adversely affect their driving ability, potentially causing danger to themselves and others. Screening for such troublesome tics should be considered in patients with TS, particularly in teenagers who are being evaluated for driver's licensing.

Overconfidence in visual perception in parkinson's disease

Increased dependence on visual cues in Parkinson's disease (PD) can unbalance the perception-action loop, impair multisensory integration, and affect everyday function of PD patients. It is currently unknown why PD patients seem to be more reliant on their visual cues. We hypothesized that PD patients may be overconfident in the reliability (precision) of their visual cues. In this study we tested coherent visual motion perception in PD, and probed subjective (self-reported) confidence in their visual motion perception. Twenty patients with idiopathic PD, 21 healthy aged-matched controls and 20 healthy young adult participants were presented with visual stimuli of moving dots (random dot kinematograms). They were asked to report: (1) whether the aggregate motion of dots was to the left or to the right, and (2) how confident they were that their perceptual discrimination was correct. Visual motion discrimination thresholds were similar (unimpaired) in PD compared to the other groups. By contrast, PD patients were significantly overconfident in their visual perceptual decisions (p = .002 and p < .001 vs. the age-matched and young adult groups, respectively). These results suggest intact visual motion perception, but overestimation of visual cue reliability, in PD. Overconfidence in visual (vs. other, e.g., somatosensory) cues could underlie increased visual dependence and impaired multisensory/sensorimotor integration in PD. It could thereby contribute to gait and balance impairments, and affect everyday activities, such as driving. Future work should investigate and compare PD confidence in somatosensory function. A better understanding of altered sensory reliance might open up new avenues to treat debilitating PD symptoms.

Driving in Parkinson's disease: a retrospective study of driving and mobility assessments

BACKGROUND

To guide decision-making about driving ability, some patients with Parkinson's disease (PD) undergo specialist driving assessment. However, decisions about driving safety in most patients need to be made without this definitive test. There is no consensus on what predicts unsafe driving in PD nor a validated prediction tool to guide clinician decision-making and the need to refer for further assessment.

OBJECTIVES

To describe the characteristics of patients with PD assessed at a Driving Mobility Centre and investigate factors that predict driving assessment outcome.

METHODS

Retrospective cohort study of patients with PD assessed between 2012 and 2016. Descriptive analyses and logistic models to determine factors predicting a negative outcome.

RESULTS

There were 86 assessments of patients with PD. The mean age was 70 years (±9.2), 86% were male, median disease duration 7 years (interquartile range 5-12.5 years) and 59% were referred by the Driver and Vehicle Licensing Agency. In total, 62% had a negative 'not drive' outcome. The Rookwood Driving Battery (RDB), depth of vision deficit, usual driving frequency, age, duration license held and response time were all predictors in univariable analysis. The RDB was the best predictor of assessment failure, conditional on other variables in a backward stepwise model (odds ratio 1.29; 95% confidence interval 1.05, 1.60; P = 0.015).

CONCLUSIONS

This is the first study to describe patients with PD undergoing driving assessments in the UK. In this population, RDB performance was the best predictor of outcome. Future prospective studies are required to better determine predictors of driving ability to guide development of prediction tools for implementation into clinical practice.

Implementation of a Community-Based Exercise Program for Parkinson Patients: Using Boxing as an Example

BACKGROUND

Persons with Parkinson's disease (PD) benefit from continuous exercise through participation in community-based exercise programs. However, community programs often lack PD-specific knowledge needed to provide safe and adequately dosed exercise.

OBJECTIVE

To evaluate the acceptability and safety of a PD-specific boxing program in the community.

METHODS

We developed specific educational resources to facilitate the boxing instructors. We also organized an educational and practical workshop for patients (n = 26) and instructors (n = 10), and assessed: (a) participants' satisfaction; (b) instructors' appreciation of the educational resources; and (c) numbers of patients interested in participating in the boxing program. After 18 months, patients and instructors completed a questionnaire evaluating: (a) participants' satisfaction; (b) adverse events; (c) facilitators and barriers; and (d) proportion of participants at follow-up.

RESULTS

Twenty-six persons with PD (62% men) and 10 boxing instructors participated in the workshop. 81% of patients and 80% of instructors were very satisfied. Instructors found the educational materials "very helpful" (60%) or "helpful" (40%). Patients expressed a clear interest (54%) or possible interest (46%) in the program. We initiated classes with 10 participants. At 18-months follow-up, the program consisted of four boxing sessions/week, led by three instructors, with 40 participants. Seventeen patients responded to the questionnaire at follow-up. Participants were "very satisfied" (53%), "satisfied" (35%) and neither satisfied nor unsatisfied (12%) with the program. Adverse effects were mild (e.g., muscle aches). Transportation and physical disability were the main barriers for participation.

CONCLUSIONS

The boxing program was well-received, with increasing numbers of participants at 18 months. The educational resources can support boxing instructors participating in current and future boxing classes being delivered in the community.

Driving in Parkinson Disease

Driving is impaired in most patients with Parkinson disease because of motor, cognitive, and visual dysfunction. Driving impairments in Parkinson disease may increase the risk of crashes and result in early driving cessation with loss of independence. Drivers with Parkinson disease should undergo comprehensive evaluations to determine fitness to drive with periodic follow-up evaluations as needed. Research in rehabilitation of driving and automation to maintain independence of patients with Parkinson disease is in progress.

A systematic review of the risk of motor vehicle collision after stroke or transient ischemic attack

BACKGROUND

Returning to driving after stroke is one of the key goals in stroke rehabilitation, and fitness to drive guidelines must be informed by evidence pertaining to risk of motor vehicle collision (MVC) in this population.

OBJECTIVES

The purpose of the present study was to determine whether stroke and/or transient ischemic attack (TIA) are associated with an increased MVC risk.

METHODS

We searched MEDLINE, CINAHL, EMBASE, PsycINFO, and TRID through December 2016. Pairs of reviewers came to consensus on inclusion, based on an iterative review of abstracts and full-text manuscripts, on data extraction, and on the quality of evidence.

RESULTS

Reviewers identified 5,605 citations, and 12 articles met inclusion criteria. Only one of three case-control studies showed an association between stroke and MVC (OR 1.9, 95% CI 1.0-3.9). Of five cohort reports, only one study, limited to self-report, found an increased risk of MVC associated with stroke or TIA (RR 2.71, 95% CI 1.11-6.61). Two of four cross-sectional studies using computerized driving simulators identified a more than two-fold risk of MVCs among participants with stroke compared with controls. The difference in one of the studies was restricted to those with middle cerebral artery stroke.

CONCLUSIONS

The evidence does not support a robust increase in risk of MVCs. While stroke clearly prevents some patients from driving at all and impairs driving performance in others, individualized assessment and clinical judgment must continue to be used in assessing and advising those stroke patients who return to driving about their MVC risk.