Cognitive test performance and crash risk in an older driver population

The effect of cannabis edibles on driving and blood THC

BACKGROUND

Cannabis has been shown to impact driving due to changes produced by delta-9-tetrahydrocannabinol (THC), the psychoactive component of cannabis. Current legal thresholds for blood THC while driving are based predominantly on evidence utilizing smoked cannabis. It is known that levels of THC in blood are lower after eating cannabis as compared to smoking yet the impact of edibles on driving and associated blood THC has never been studied.

METHODS

Participants drove a driving simulator before and after ingesting their preferred legally purchased cannabis edible. In a counterbalanced control session, participants did not consume any THC or cannabidiol (CBD). Blood was collected for measurement of THC and metabolites as well as CBD. Subjective experience was also assessed.

RESULTS

Participants consumed edibles with, on average, 7.3 mg of THC, which is less than the maximum amount available in a single retail package in Ontario, providing an ecologically valid test of cannabis edibles. Compared to control, cannabis edibles produced a decrease in mean speed 2 h after consumption but not at 4 and 6 h. Under dual task conditions in which participants completed a secondary task while driving, changes in speed were not significant after the correction for multiple comparison. No changes in standard deviation of lateral position (SDLP; 'weaving'), maximum speed, standard deviation of speed or reaction time were found at any time point or under either standard or dual task conditions. Mean THC levels were significantly increased, relative to control, after consuming the edible but remained relatively low at approximately 2.8 ng/mL 2 h after consumption. Driving impairment was not correlated with blood THC. Subjective experience was altered for 7 h and participants were less willing/able to drive for up to 6 h, suggesting that the edible was intoxicating.

INTERPRETATION

This is the first study of the impact of cannabis edibles on simulated driving. Edibles were intoxicating as revealed by the results of subjective assessments (VAS), and there was some impact on driving. Detection of driving impairment after the use of cannabis edibles may be difficult.

Effectiveness of road safety interventions: An evidence and gap map

Background

Road Traffic injuries (RTI) are among the top ten leading causes of death in the world resulting in 1.35 million deaths every year, about 93% of which occur in low- and middle-income countries (LMICs). Despite several global resolutions to reduce traffic injuries, they have continued to grow in many countries. Many high-income countries have successfully reduced RTI by using a public health approach and implementing evidence-based interventions. As many LMICs develop their highway infrastructure, adopting a similar scientific approach towards road safety is crucial. The evidence also needs to be evaluated to assess external validity because measures that have worked in high-income countries may not translate equally well to other contexts. An evidence gap map for RTI is the first step towards understanding what evidence is available, from where, and the key gaps in knowledge.

Objectives

The objective of this evidence gap map (EGM) is to identify existing evidence from all effectiveness studies and systematic reviews related to road safety interventions. In addition, the EGM identifies gaps in evidence where new primary studies and systematic reviews could add value. This will help direct future research and discussions based on systematic evidence towards the approaches and interventions which are most effective in the road safety sector. This could enable the generation of evidence for informing policy at global, regional or national levels.

Search Methods

The EGM includes systematic reviews and impact evaluations assessing the effect of interventions for RTI reported in academic databases, organization websites, and grey literature sources. The studies were searched up to December 2019.

Selection Criteria

The interventions were divided into five broad categories: (a) human factors (e.g., enforcement or road user education), (b) road design, infrastructure and traffic control, (c) legal and institutional framework, (d) post-crash pre-hospital care, and (e) vehicle factors (except car design for occupant protection) and protective devices. Included studies reported two primary outcomes: fatal crashes and non-fatal injury crashes; and four intermediate outcomes: change in use of seat belts, change in use of helmets, change in speed, and change in alcohol/drug use. Studies were excluded if they did not report injury or fatality as one of the outcomes.

Data Collection and Analysis

The EGM is presented in the form of a matrix with two primary dimensions: interventions (rows) and outcomes (columns). Additional dimensions are country income groups, region, quality level for systematic reviews, type of study design used (e.g., case-control), type of road user studied (e.g., pedestrian, cyclists), age groups, and road type. The EGM is available online where the matrix of interventions and outcomes can be filtered by one or more dimensions. The webpage includes a bibliography of the selected studies and titles and abstracts available for preview. Quality appraisal for systematic reviews was conducted using a critical appraisal tool for systematic reviews, AMSTAR 2.

Main Results

The EGM identified 1859 studies of which 322 were systematic reviews, 7 were protocol studies and 1530 were impact evaluations. Some studies included more than one intervention, outcome, study method, or study region. The studies were distributed among intervention categories as: human factors (n = 771), road design, infrastructure and traffic control (n = 661), legal and institutional framework (n = 424), post-crash pre-hospital care (n = 118) and vehicle factors and protective devices (n = 111). Fatal crashes as outcomes were reported in 1414 records and non-fatal injury crashes in 1252 records. Among the four intermediate outcomes, speed was most commonly reported (n = 298) followed by alcohol (n = 206), use of seatbelts (n = 167), and use of helmets (n = 66). Ninety-six percent of the studies were reported from high-income countries (HIC), 4.5% from upper-middle-income countries, and only 1.4% from lower-middle and low-income countries. There were 25 systematic reviews of high quality, 4 of moderate quality, and 293 of low quality.

Authors' Conclusions

The EGM shows that the distribution of available road safety evidence is skewed across the world. A vast majority of the literature is from HICs. In contrast, only a small fraction of the literature reports on the many LMICs that are fast expanding their road infrastructure, experiencing rapid changes in traffic patterns, and witnessing growth in road injuries. This bias in literature explains why many interventions that are of high importance in the context of LMICs remain poorly studied. Besides, many interventions that have been tested only in HICs may not work equally effectively in LMICs. Another important finding was that a large majority of systematic reviews are of low quality. The scarcity of evidence on many important interventions and lack of good quality evidence-synthesis have significant implications for future road safety research and practice in LMICs. The EGM presented here will help identify priority areas for researchers, while directing practitioners and policy makers towards proven interventions.

Cannabis and Driving in Older Adults

Importance

Epidemiological studies have found that cannabis increases the risk of a motor vehicle collision. Cannabis use is increasing in older adults, but laboratory studies of the association between cannabis and driving in people aged older than 65 years are lacking.

Objective

To investigate the association between cannabis, simulated driving, and concurrent blood tetrahydrocannabinol (THC) levels in older adults.

Design, Setting, and Participants

Using an ecologically valid counterbalanced design, in this cohort study, regular cannabis users operated a driving simulator before, 30 minutes after, and 180 minutes after smoking their preferred legal cannabis or after resting. This study was conducted in Toronto, Canada, between March and November 2022 with no follow-up period. Data were analyzed from December 2022 to February 2023.

Exposures

Most participants chose THC-dominant cannabis with a mean (SD) content of 18.74% (6.12%) THC and 1.46% (3.37%) cannabidiol (CBD).

Main outcomes and measures

The primary end point was SD of lateral position (SDLP, or weaving). Secondary outcomes were mean speed (MS), maximum speed, SD of speed, and reaction time. Driving was assessed under both single-task and dual-task (distracted) conditions. Blood THC and metabolites of THC and CBD were also measured at the time of the drives.

Results

A total of 31 participants (21 male [68%]; 29 White [94%], 1 Latin American [3%], and 1 mixed race [3%]; mean [SD] age, 68.7 [3.5] years), completed all study procedures. SDLP was increased and MS was decreased at 30 but not 180 minutes after smoking cannabis compared with the control condition in both the single-task (SDLP effect size [ES], 0.30; b = 1.65; 95% CI, 0.37 to 2.93; MS ES, -0.58; b = -2.46; 95% CI, -3.56 to -1.36) and dual-task (SDLP ES, 0.27; b = 1.75; 95% CI, 0.21 to 3.28; MS ES, -0.47; b = -3.15; 95% CI, -5.05 to -1.24) conditions. Blood THC levels were significantly increased at 30 minutes but not 180 minutes. Blood THC was not correlated with SDLP or MS at 30 minutes, and SDLP was not correlated with MS. Subjective ratings remained elevated for 5 hours and participants reported that they were less willing to drive at 3 hours after smoking.

Conclusions and relevance

In this cohort study, the findings suggested that older drivers should exercise caution after smoking cannabis.

Translation and concurrent validity, sensitivity and specificity of Chinese version of Short Orientation Memory Concentration Test in people with a first cerebral infarction

Purpose

This study aimed to translate the English version of the Short Orientation-Memory-Concentration (SOMC) test into a Chinese version, denoted the C-SOMC test, and to investigate the concurrent validity, sensitivity, and specificity of the C-SOMC test against a longer and widely used screening instrument in people with a first cerebral infarction.

Methods

An expert group translated the SOMC test into Chinese using a forward-backward procedure. Eighty-six participants (67 men and 19 women, mean age = 59.31 ± 11.57 years) with a first cerebral infarction were enrolled in this study. The validity of the C-SOMC test was determined using the Chinese version of Mini Mental State Examination (C-MMSE) as the comparator. Concurrent validity was determined using Spearman's rank correlation coefficients. Univariate linear regression was used to analyze items' abilities to predict the total score on the C-SOMC test and the C-MMSE score. The area under the receiver operating characteristic curve (AUC) was used to demonstrate the sensitivity and specificity of the C-SOMC test at various cut-off values distinguishing cognitive impairment from normal cognition.

Results

The total score for the C-SOMC test and the score for item 1 on this test exhibited moderate-to-good correlations with the C-MMSE score, with respective ρ-values of 0.636 and 0.565 (P < 0.001). The scores for each of items 2, 4, 5, 6, and 7 yielded fair correlations with C-MMSE score, with ρ-value from 0.272 to 0.495 (P < 0.05). The total score on the C-SOMC test and the item score were good predictors (adjusted R² = 0.049 to 0.615) of the C-MMSE score, and six items were good predictors (adjusted R² = 0.134 to 0.795) of the total score. The AUC was 0.92 for the C-SOMC test. A cut-off of 17/18 on the C-SOMC test gave optimal performance: correct classification of 75% of participants, with 75% sensitivity and 87.9% specificity.

Conclusion

The C-SOMC test demonstrated good concurrent validity, sensitivity and specificity in a sample of people with a first cerebral infarction, demonstrating that it could be used to screen for cognitive impairment in stroke patients.

Age-related effects of executive function on takeover performance in automated driving

The development of highly automated vehicles can meet elderly drivers' mobility needs; however, worse driving performance after a takeover request (TOR) is frequently found, especially regarding non-driving related tasks (NDRTs). This study aims to detect the correlation between takeover performance and underlying cognitive factors comprising a set of higher order cognitive processes including executive functions. Thirty-five young and 35 elderly participants were tested by computerized cognitive tasks and simulated driving tasks to evaluate their executive functions and takeover performance. Performance of n-back tasks, Simon tasks, and task switching were used to evaluate updating, inhibition, and shifting components of executive functions by principal component analysis. The performance of lane changing after TOR was measured using the standard deviation of the steering wheel angle and minimum time-to-collision (TTC). Differences between age groups and NDRT engagement were assessed by two-way mixed analysis of variance. Older participants had significantly lower executive function ability and were less stable and more conservative when engaged in NDRT. Furthermore, a significant correlation between executive function and lateral driving stability was found. These findings highlight the interaction between age-related differences in executive functions and takeover performance; thus, provide implications for designing driver screening tests or human-machine interfaces.

Strong evidence for age as the single most dominant predictor of medically supervised driving test-mini mental status test outcomes provide only weak but significant moderate additional predictive value

Background

With age, medical conditions impairing safe driving accumulate. Consequently, the risk of accidents increases. To mitigate this risk, Swiss law requires biannual assessments of the fitness to drive of elderly drivers. Drivers may prove their cognitive and physical capacity for safe driving in a medically supervised driving test (MSDT) when borderline cases, as indicated by low performance in a set of four cognitive tests, including e.g. the mini mental status test (MMST). Any prognostic, rather than indicative, relations for MSDT outcomes have neither been confirmed nor falsified so far. In order to avoid use of unsubstantiated rules of thumb, we here evaluate the predictive value for MSDT outcomes of the outcomes of the standard set of four cognitive tests, used in Swiss traffic medicine examinations.

Methods

We present descriptive information on age, gender and cognitive pretesting results of all MSDTs recorded in our case database from 2017 to 2019. Based on these retrospective cohort data, we used logistic regression to predict the binary outcome MSDT. An exploratory analysis used all available data (model 1). Based on the Akaike Information Criterion (AIC), we then established a model including variables age and MMST (model 2). To evaluate the predictive value of the four cognitive assessments, model 3 included cognitive test outcomes only. Receiver operating characteristics (ROC) and area under the curve (AUC) allowed evaluating discriminative performance of the three different models using independent validation data.

Results

Using N = 188 complete data sets of a total of 225 included cases, AIC identified age (p < 0.0008) and MMST (p = 0.024) as dominating predictors for MSDT outcomes with a median AUC of 0.71 (95%-CI 0.57–0.85) across different training and validation splits, while using the four cognitive test results exclusively yielded a median AUC of 0.55 (95%-CI 0.40–0.71).

Conclusions

Our analysis provided strong evidence for age as the single most dominant predictor of MSDT outcomes. Adding MMST provides only weak additional predictive value for MSDT outcomes. Combining the results of four cognitive test used as standard screen in Swiss traffic medicine alone, proved to be of poor predictive value. This highlights the importance of MSDTs for balancing between the mitigation of risks by and the right to drive for the elderly.

Driving Performance in Older Adults: Current Measures, Findings, and Implications for Roadway Safety

Background and Objectives

Over 10,000 people a day turn 65 in the United States. For many older adults, driving represents an essential component of independence and is one of the most important factors in overall mobility. Recent survey studies in older adults suggest that up to 60% of older adult drivers with mild cognitive impairment, and up to 30% with dementia, continue to drive. The purpose of this review is to provide a comprehensive and detailed resource on the topics of cognition and driving for clinicians, researchers, and policymakers working on efforts related to older adult drivers.

Research Design and Methods

Publications on PubMed and Medline and discussions with experts working in geriatrics, technology, driving policy, psychology, and diverse aspects of driving performance were utilized to inform the current review.

Results

Research indicates that there is a complex and inverse correlation between multiple cognitive measures, driving performance, and risky driving behaviors. The fragmented nature of available peer-reviewed literature, and a reliance on correlative data, do not currently allow for the identification of the temporal and reciprocal nature of the interplay between cognition and driving endpoints.

Discussion and Implications

There are currently no widely accepted definitions, conceptual models, or uniform set of analyses for conducting geriatric research that is focused on driving. Establishing conventions for conducting research that harmonizes the fields of geriatrics, cognition, and driving research is critical for the development of the evidence base that will inform clinical practice and road safety policy.

Age Predicts Older Adults' Driving Self-Regulation but Not Dangerous Driving Behaviors after Controlling for Executive Function

OBJECTIVES

The aim of the study was to examine the unique contributions of age to objectively measure driving frequency and dangerous driving behaviors in healthy older adults after adjusting for executive function (EF).

METHOD

A total of 28 community-dwelling older adults (mean age = 82.0 years, standard deviation [SD] = 7.5) without dementia who were in good physical health and enrolled in a longitudinal aging study completed several EF and clinical self-report measures at baseline. Participants subsequently had a sensor installed in their vehicle for a mean of 208 (SD = 38, range = 127-257) days.

RESULTS

Participants drove for an average of 54 min per day. Mixed-effects models indicated that after controlling for EF, older age was associated with less time driving per day, decreased number of trips, and less nighttime driving. Age was not associated with hard brakes or hard accelerations.

DISCUSSION

After accounting for EF, greater age is associated with higher driving self-regulation but not dangerous driving behaviors in healthy older adults. Future studies should recruit larger samples and collect sensor-measured driving data over a more extended time frame to better determine how and why these self-regulation changes take place.

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.

Driving and Alzheimer's dementia or mild cognitive impairment: a systematic review of the existing guidelines emphasizing on the neurologist's role

BACKGROUND

Driving is a complex task requiring the integrity and the cooperation of cognition, motor, and somatosensory skills, all of which are impacted by neurological diseases.

OBJECTIVE

Identification of neurologist's role when assessing fitness to drive of cognitively impaired individuals.

METHODS

We performed a systematic review of the guidelines/recommendations (G/Rs) regarding the evaluation of driving fitness of patients with mild cognitive impairment (MCI) and/or dementia. Emphasis was put on the neurological and neuropsychological aspects of the evaluation.

RESULTS

Eighteen G/Rs were included in the review (9 national guidelines, 5 recommendation papers, 3 consensus statements, and 1 position paper). All G/Rs referred to drivers with dementia and 9/18 referred to drivers with MCI. A common approach among G/Rs is the initial trichotomization of patients in safe to drive, unsafe to drive, and undetermined cases, which are referred to a second-line evaluator. First-line evaluators are general practitioners in 10/18 G/Rs; second-line evaluators are neurologists in 7/18 G/Rs. Specific neuropsychological tests are proposed in 11/18 G/Rs and relative cut-off values in 7/18. The most commonly used tests are the MMSE, TMT, and CDT. A thorough neurological examination is proposed in only 1/18 G/R.

CONCLUSION

Although extensive multi-disciplinary research has provided useful information for driving behavior of cognitively impaired individuals, we are still far from a widely accepted approach of driving ability evaluation in this increasing population. A comprehensive assessment from a multi-disciplinary team in which the neurologist plays a critical role seems to be required, although this has not yet been implemented in any G/Rs.

Age-Related Effect of Sleepiness on Driving Performance: A Systematic-Review

Background: Several studies highlighted that sleepiness affects driving abilities. In particular, road traffic injuries due to excessive daytime sleepiness are about 10–20%. Considering that aging is related to substantial sleep changes and the number of older adults with driving license is increasing, the current review aims to summarize recent studies on this issue. Further, we intend to provide insights for future research. Methods: From the 717 records screened, ten articles were selected and systematically reviewed. Results: Among the selected articles, (a) five studies investigated sleepiness only by self-reported standardized measures; (b) two studies assessed sleepiness also using a behavioral task; (c) three studies obtained objective measures by electroencephalographic recordings. Conclusions: The available literature on the topic reports several limitations. Overall, many findings converge in evidencing that older drivers are less vulnerable to sleep loss and sleepiness-related driving impairments than young adults. These discrepancies in sleepiness vulnerability between age groups may be ascribed to differences in subjects’ lifestyles. Moreover, it has been hypothesized that older adults self-regulate their driving and avoid specific dangerous situations. We believe that an easy protocol to objectively evaluate the vigilance level in elderly and young adults is required, and further studies are needed.

Using Speech Data From Interactions With a Voice Assistant to Predict the Risk of Future Accidents for Older Drivers: Prospective Cohort Study

Background

With the rapid growth of the older adult population worldwide, car accidents involving this population group have become an increasingly serious problem. Cognitive impairment, which is assessed using neuropsychological tests, has been reported as a risk factor for being involved in car accidents; however, it remains unclear whether this risk can be predicted using daily behavior data.

Objective

The objective of this study was to investigate whether speech data that can be collected in everyday life can be used to predict the risk of an older driver being involved in a car accident.

Methods

At baseline, we collected (1) speech data during interactions with a voice assistant and (2) cognitive assessment data—neuropsychological tests (Mini-Mental State Examination, revised Wechsler immediate and delayed logical memory, Frontal Assessment Battery, trail making test-parts A and B, and Clock Drawing Test), Geriatric Depression Scale, magnetic resonance imaging, and demographics (age, sex, education)—from older adults. Approximately one-and-a-half years later, we followed up to collect information about their driving experiences (with respect to car accidents) using a questionnaire. We investigated the association between speech data and future accident risk using statistical analysis and machine learning models.

Results

We found that older drivers (n=60) with accident or near-accident experiences had statistically discernible differences in speech features that suggest cognitive impairment such as reduced speech rate (P=.048) and increased response time (P=.040). Moreover, the model that used speech features could predict future accident or near-accident experiences with 81.7% accuracy, which was 6.7% higher than that using cognitive assessment data, and could achieve up to 88.3% accuracy when the model used both types of data.

Conclusions

Our study provides the first empirical results that suggest analysis of speech data recorded during interactions with voice assistants could help predict future accident risk for older drivers by capturing subtle impairments in cognitive function.

Spatial Mental Transformation Skills Discriminate Fitness to Drive in Young and Old Adults

Literature on driving research suggests a relationship between cognition and driving performance in older and younger drivers. There is little research on adults and driving, despite them being the largest age cohort behind the wheel. Among the cognitive domains, visuospatial abilities are expected to be highly predictive of driving skills and driving fitness. The relationship between specific spatial mental transformation skills (i.e., object and self-based ones) and driving performance has not yet been examined. The present study aimed to investigate the relationship between overall cognitive functioning, self and object-based spatial mental transformation skills, and driving performance in a sample of younger and older adult drivers. Participants were comprised of one hundred younger and 83 older adult Italian drivers. Participants completed a computerized driving test assessing traffic stress resilience, visual and motor reaction time, and the ability to obtain an overview of the traffic scenario (DT, vRT, mRT, and ATAV respectively in the Shufried®-Vienna Test System-DRIVESC). The Mental Rotation Test (MRT) and the Object Perspective Taking Test (OPT) were administered in order to assess object-based and self-based spatial mental transformation skills. The Montreal Cognitive Assessment Test (MoCA) was administered control for global cognitive functioning. The effects of education and gender were also controlled in the analysis. The results of the present study suggested that: (1) The effect of age, favoring younger participants, was found in DT, vRT, mRT, and ATAVT tests. (2) The effect of global cognitive functioning was found in DT and ATAV tests. (3) The effect of the spatial mental transformation tests was found in DT, vRT (MRT only), and ATAVT (OPT only) tests. Taken together, these results suggest the specific contribution of spatial mental transformation skills in the execution of complex behaviors connected to the fitness to drive. Prospectively, the results of the present study relating spatial mental transformation skills and driving processes may be a valuable source of knowledge for researchers dealing with the relationship between cognitive resources and navigation aids.

Relationship Between Physical Activity and Motor Vehicle Crashes Among Older Adult Drivers

Background: There are approximately 42 million licensed drivers aged 65 years or older in the United States, who face unique age-related risks while driving. While physical activity affects several chronic conditions thought to be associated with motor vehicle crashes (MVCs), it is unclear if increased physical activity leads to fewer MVCs. This study explores whether self-reported vigorous and moderate physical activity is associated with MVCs in the previous year. Methods: Using cross-sectional data from the LongROAD study, a large multisite prospective cohort study of 2990 older adult drivers, we examined variables related to physical activity and performed a multivariate regression analysis to examine the association of physical activity health behaviors with self-reported MVCs. Results: Overall, 41.2% of participants reported vigorous and 69.6% of participants reported moderate exercise at least once per week. Eleven percent of participants reported at least 1 MVC in the previous year. Neither vigorous nor moderate physical activity was significantly associated with self-reported MVCs in the previous year. Select variables that were significantly associated with self-reported MVC included self-reported unsafe driving practices (odds ratio [OR] 1.55, confidence interval [CI] 1.05-2.29), and fall in the past 12 months (OR 1.46, CI 1.14-1.85). Conclusions: We were unable to detect a significant association between self-reported physical activity and MVCs in the past year among this group of older drivers. Use of objective measures of activity may better clarify this relationship.

Effects of multitasking and intention-behaviour consistency when facing yellow traffic light uncertainty

We examined the effects of multitasking on resolving response bistability to yellow traffic lights, using the performance metrics of reaction time and stopping frequency. We also examined whether people's actual behaviours, measured by implicit foot pedal responses, differed from their intentions related to these factors, as measured by explicit verbal commands. In a dual-task paradigm, participants responded to random traffic light changes, presented over a static background photograph of an intersection, using either foot pedals or verbal commands, while simultaneously identifying spoken words as either "animals" or "artefacts" via button pressing. The dual-task condition was found to prolong reaction times relative to a single-task condition. In addition, verbal commands were faster than the foot pedal responses, and conservativeness was the same for both types of responses. A second experiment, which provided a more dynamic simulation of the first experiment, confirmed that conservativeness did not differ between verbal commands and foot pedal responses. We conclude that multitasking affects a person's ability to resolve response bistability to yellow traffic lights. If one considers that prolonged reaction times reduce the amount of distance available to safely stop at intersections, this study underscores how multitasking poses a considerable safety risk for drivers approaching a yellow traffic light.

Exploring the contribution of executive functions to on-road driving performance during aging: A latent variable analysis

With the aging of the population the issue of older drivers safety has gained importance in recent years. Age-related cognitive decline is frequently cited as the main cause of unsafe driving performance in older drivers.

OBJECTIVE

The present study investigated how executive functions (EFs), measured as latent variables, are related to on-road driving performance during aging.

METHOD

One hundred and twenty-six participants aged from twenty to eighty-two, completed a two hundred and forty-seven km on-road driving test and a set of executive tasks selected to tap three often postulated EFs: inhibition (inhibiting prepotent responses), updating (updating working memory representations), and shifting (shifting task sets).

RESULTS

Confirmatory factor analysis reproduces previous results obtained by Miyake et al. (2000), Miyake and Friedman (2012) of unity and diversity of EFs in an adult life span sample. Structural equation modeling suggested that on-road driving performance was related to inhibition. Furthermore, findings indicate that the age-related driving performance decline in normal aging may be mediated by the inhibition function.

CONCLUSIONS

The results highlight the importance of a proper method to assess executive functioning in a specific domain as well as emphasising the major role of those functions in driving performance while aging.

Driving in the elderly in health and disease

Driving is a complex, multifaceted instrumental activity of daily living that has an independent influence on multiple health and well-being outcomes among older adults. Therefore, the benefits of driving to the individual must be balanced, through careful assessment and diagnosis, with the potential risk to self and others posed by a medically impaired driver. The influence of dementia changes substantially during the disease progression from very mild to mild, and driving is not advised for those who have progressed to the moderate stage of Alzheimer disease. Fortunately, validated high-quality screening instruments, including modern simulators and other technology aids, can help clinicians trichotomize risk (i.e., high, moderate, or low) and determine which patients need further evaluation by a driving specialist (e.g., those in the moderate range). Moreover, a body of evidence is building regarding the efficacy of certain intervention pathways to maintain current levels of driving performance among individuals with dementia, or at least slow its decline. Even with the progression of advanced driving technologies, understanding driving ability of patients with dementia will remain a critical challenge to clinicians for the foreseeable future.

Age, Gender and Mechanism of Injury Interactions in Post-Concussion Syndrome

BACKGROUND

Certain factors such as age and gender seem to affect the risk of developing post-concussion syndrome (PCS). We assessed the interactions between age, gender, concussion history and mechanism of injury in PCS patients so that a better understanding could guide the development of targeted prevention strategies.

METHODS

Demographic data including age, gender, concussion mechanism of injury and concussion history were collected from (1) a prospective study evaluating PCS biomarkers and (2) a retrospective chart review of PCS patients. A total of 437 PCS patients who were assessed at the Canadian Concussion Centre or Toronto Western Hospital, Toronto, ON, were included.

RESULTS

Overall, there were more men with PCS; however, a greater percentage of women had PCS after a single concussion. The results showed that age, gender and concussion history are conditionally dependent on the mechanism of injury, and independent of one another. The relative frequency of having PCS was greater in the following instances: (1) being a woman and having had concussion from a fall or motor vehicle collision (MVC), (2) being older and having had concussion from a fall or MVC or (3) having a single concussion with cause being MVC or fall.

CONCLUSION

In patients with PCS, age and gender interact with the mechanism of injury to influence the risk of concussion. Targeted prevention strategies may be essential to prevent injuries leading to PCS.

Relationships Between Older Drivers' Cognitive Abilities as Assessed on the MoCA and Glance Patterns During Visual-Manual Radio Tuning While Driving

Objective

Research has established that long off-road glances increase crash risk, and other work has shown increased off-road glance behavior in older drivers. This study investigated the relationship between older drivers' (M = 66.3, range 61-69 years) cognitive abilities and the duration of off-road glances while engaged in secondary visual-manual activities.

Method

Twenty-two drivers completed the Montreal Cognitive Assessment (MoCA) prior to driving an instrumented vehicle and completing a set of radio-tuning tasks. Glance behavior was recorded and manually coded into 7 glance regions (toward the forward roadway, instrument cluster, center stack, rearview mirror, left, right, and other).

Results

On average, older drivers with higher MoCA scores used shorter glances and glanced away from the forward roadway for less total time when manually tuning the radio.

Discussion

These findings suggest that lower MoCA scores may represent a driving force behind the "age" differences reported in earlier studies of off-road glance behavior. Questions are raised concerning the identification of MoCA scores that might be used as inclusion cut-points in driving research and in identifying individuals needing further evaluation related to suitability for continuance of driving.

Default-mode network dynamics are restricted during high speed discrimination in healthy aging: Associations with neurocognitive status and simulated driving behavior

Numerous daily tasks, including car driving, require fine visuospatial tuning. One such visuospatial ability, speed discrimination, declines with aging but its neural underpinnings remain unknown. In this study, we use fMRI to explore the effect of aging during a high speed discrimination task and its neural underpinnings, along with a complete neuropsychological assessment and a simulated driving evaluation in order to examine how they interact with each other through a multivariate regression approach. Beyond confirming that high speed discrimination performance is diminished in the elderly, we found that this deficit might be partly due to a lack of modulation in the activity and connectivity of the default mode network (DMN) in this age group, as well as an over-recruitment of frontoparietal and cerebellar regions, possibly as a compensatory mechanism. In addition, younger adults tended to drive at faster speeds, a behavior that was associated to adequate DMN dynamics and executive functioning, an effect that seems to be lost in the elderly. In summary, these results reveal how age-related declines in fine visuospatial abilities, such as high speed discrimination, were distinctly mediated by DMN functioning, a mechanism also associated to speeding behavior in a driving simulator.

Does Chronic Kidney Disease-Induced Cognitive Impairment Affect Driving Safety?

PURPOSE OF REVIEW

One of the principal mechanisms by which illness can affect driving safety is by impairing cognition. Nevertheless, despite the substantial evidence demonstrating cognitive impairment in chronic kidney disease (CKD), little is known about the effects of CKD on driving safety.

OBJECTIVE

Investigate the current national medical guidelines and research literature with respect to CKD and driving safety.

SOURCES OF INFORMATION

Medline, CINAHL, PEDro, Scopus as of August 2017. The most up to date national driving guidelines and available information provided by the provincial and territorial ministries of transportation across Canada.

FINDINGS

Fives studies of driving fitness in patients with CKD have been published with minimal data available for patients at early stages of the disease. Amongst these studies, only two come from an era when modern end stage renal disease therapies were routinely provided. The first study demonstrated that 40% of 186 surveyed patients on hemodialysis felt uncomfortable driving and that 1/3 of patients were involved in motor vehicle collisions (MVC) since starting dialysis. Of the patients who felt comfortable driving, more than 75% were found to be at increased driving risk. The second study reported that 15% of patients on hemodialysis were involved in MVCs over a three year span and that the "Am I A Safe Driver" assessment tool by the American Medical Association may not capture all patients at high driving risk. Despite these alarming numbers, national guidelines place few driving restrictions on this patient population and only 3 of 11 available provincial or territorial driving forms include kidney disease as a category that physicians should consider when assessing medical fitness to drive.

LIMITATIONS

Our review is limited by the lack of randomized control studies evaluating the effects of CKD on driving safety.

IMPLICATIONS

Our review demonstrates that driving safety in this patient population remains poorly understood. The limited evidence that does exist, however, suggests that these patients are at substantial risk for unsafe driving. Future research is necessary to determine the impact of CKD-associated cognitive impairment on driving risk, and to parse out the contributions of CKD and its various treatments to driving impairment.

General cognitive impairment as a risk factor for motor vehicle collision involvement: a prospective population-based study

This study examined whether cognitive impairment and decline as assessed by a brief mental status screening test is associated with future crash risk in a cohort of older drivers. A three-year prospective study was conducted in a population-based sample of 2000 licensed drivers, aged 70 years and older. At the baseline visit, cognitive impairment was defined as <24 on the Mini Mental State Exam (MMSE). Decline was defined as those with a one-year change in MMSE scores in the lowest quartile (largest decrease). Motor vehicle collision involvement was obtained from the Alabama Department of Public Safety. Poisson regression was used to calculate crude and adjusted rate ratios (RR). There were 278 crashes during the follow-up period. Rates of crash involvement were higher for those with cognitive impairment (crude RR = 2.33) compared to those without impairment at baseline; adjustment for potential confounders namely age and visual processing speed attenuated this relationship (adjusted RR = 1.26, 95% confidence interval (CI) 0.65–2.44). Drivers who experienced a pronounced decline in estimated MMSE scores in one year were 1.64 (95% CI 1.04–2.57) times more likely to have a future at-fault crash, as compared to those whose scores did not decline. Evaluation of MMSE over time may provide important insight in an older driver’s future risk of at-fault crash involvement.

Associations of Near-Miss Traffic Incidents with Attention and Executive Function among Older Japanese Drivers

Background: Attention and executive function may play an important role in ensuring safe driving as they involve paying attention to complex information and making an instantaneous judgment during driving. We hypothesized that poor performance in attention and executive function may increase the risk of near-miss incidents among older drivers. Objective: The aim of this study was to examine associations of current experience of near-miss traffic incidents with attention and executive function among older Japanese drivers. Methods: The study included 3,421 general older drivers (mean age: 71.7 ± 4.9 years; 56.3% men) with a valid driver’s license who were currently driving at least once per week and who had participated in a community-based cohort study between February 2015 and August 2016. The participants were asked about their experiences of near-miss traffic incidents in 10 situations that had almost happened during driving in the previous year. Results: Of the 3,421 older drivers, 1,840 (53.8%) had experienced near-miss incidents during driving in the previous year at least once. Male sex (OR 1.46, 95% CI 1.27–1.69) and high driving frequency (OR 1.11, 95% CI 1.07–1.15) were significantly associated with the current experience of near-miss traffic incidents when the overall data were analyzed. In young-old drivers aged 65–74 years, poor performance in attention as assessed by the Trail Making Test-part A (OR 1.45, 95% CI 1.05–2.00) was significantly associated with near-miss traffic incidents. Conclusion: Male sex, high driving frequency, and poor performance in attention (in young-old drivers) were associated with near-miss traffic incidents. Improvement in attention may play a role in decreasing the risk of traffic accidents among older drivers.

Driving in Somerset

Aims and Methods

The number of drivers on our roads with dementia is likely to increase as the elderly population grows. We performed a retrospective analysis of patients referred to our Memory Clinic in Taunton who were still driving despite a high suspicion of dementia.

Results

Twenty per cent of the patients were still driving at the time of their assessment. Ten per cent had a diagnosis of Alzheimer's disease and 10% mild cognitive impairment. The patients and/or carers stated that the patient had not been told to stop driving and none of the referral letters documented any advice about driving.

Clinical Implications

Referrers should advise all patients with possible dementia to refrain from driving until assessment by a specialist team is completed. They should be informed of the risk of medico-legal consequences if they continue to drive.

A validation of the low mileage bias using naturalistic driving study data

INTRODUCTION

This paper evaluated the low mileage bias (LMB) phenomenon for senior drivers using data mined from the Second Strategic Highway Research Program (SHRP 2) Naturalistic Driving Study. Supporters of the LMB construct postulate that it is only those seniors who drive the lowest annual mileage who are primarily responsible for the increased crash rates traditionally attributed to this population in general.

METHOD

The current analysis included 802 participants, all aged 65 or older who were involved in 163 property damage and injury crashes, and deemed to be at-fault in 123 (75%) of those instances. Poisson regression models were used to evaluate the association between annualized mileage driven and crash risk.

RESULTS

Results show that the crash rate for drivers with lower annualized mileage (i.e., especially for those driving fewer than approximately 3000miles per year) was significantly higher than that of drivers with higher annualized mileage, and that 25% of the overall sample were low- mileage drivers according to this criterion. Data were also evaluated by gender and meta-age group (i.e., younger-old: 65-74 and older-old: 75-99), and the results were consistent across these sub-groups.

CONCLUSIONS

This study provides strong support for the existence of the LMB.

PRACTICAL APPLICATIONS

These results can help to reshape how transportation safety stakeholders view senior drivers in general and help them to focus their efforts on those seniors most in need of either risk-reducing countermeasures or alternative means of transportation.

Effect of Speed of Processing Training on Older Driver Screening Measures

Objective: Computerized training for cognitive enhancement is of great public interest, however, there is inconsistent evidence for the transfer of training gains to every day activity. Several large trials have focused on speed of processing (SOP) training with some promising findings for long-term effects on daily activity, but no immediate transfer to other cognitive tests. Here, we examine the transfer of SOP training gains to cognitive measures that are known predictors of driving safety in older adults. Methods: Fifty-three adults aged 65-87 years who were current drivers participated in a two group non-randomized design with repeated measures and a no-contact matched control group. The Intervention group completed an average of 7.9 (SD = 3.0) hours of self-administered online SOP training at home. Control group was matched on age, gender and test-re-test interval. Measures included the Useful Field of View (UFOV) test, a Hazard Perception test, choice reaction time (Cars RT), Trail Making Test B, a Maze test, visual motion threshold, as well as road craft and road knowledge tests. Results: Speed of processing training resulted in significant improvement in processing speed on the UFOV test relative to controls, with an average change of -45.8 ms (SE = 14.5), and effect size of ω2 = 0.21. Performance on the Maze test also improved, but significant slowing on the Hazard Perception test was observed after SOP training. Training effects on the UFOV task was associated with similar effects on the Cars RT, but not the Hazard Perception and Maze tests, suggesting transfer to some but not all driving related measures. There were no effects of training on any of the other measures examined. Conclusion: Speed of processing training effects on the UFOV task can be achieved with self-administered, online training at home, with some transfer to other cognitive tests. However, differential effects of training may be observed for tasks requiring goal-directed search strategies rather than diffuse attention.

Analyzing injury severity of bus passengers with different movements

OBJECTIVE

Though public transport vehicles are rarely involved in mass casualty accidents, when they are, the number of injuries and fatalities is usually high due to the high passenger capacity. Of the few studies that have been conducted on bus safety, the majority focused on vehicle safety features, road environmental factors, as well as driver characteristics. Nevertheless, few studies have attempted to investigate the underlying risk factors related to bus occupants. This article presents an investigation aimed at identifying the risk factors affecting injury severity of bus passengers with different movements.

METHOD

Three different passenger movement types including standing, seated, and boarding/alighting were analyzed individually using classification and regression tree (CART) method based on publicly available accident database of Great Britain.

RESULTS

According to the results of exploratory analyses, passenger age and vehicle maneuver are associated with passenger injury severity in all 3 types of accidents. Moreover, the variable "skidding and overturning" is associated with injury severity of seated passengers and driver age is correlated with injury severity of standing and boarding/alighting passengers.

CONCLUSIONS

The CART method shows its ability to identify and easily explain the complicated patterns affecting passenger injury severity. Several countermeasures to reduce bus passenger injury severity are recommended.

Predictors of older drivers' involvement in high-range speeding behavior

OBJECTIVE

Even small increases in vehicle speed raise crash risk and resulting injury severity. Older drivers are at increased risk of involvement in casualty crashes and injury compared to younger drivers. However, there is little objective evidence about older drivers' speeding. This study investigates the nature and predictors of high-range speeding among drivers aged 75-94 years.

METHODS

Speed per second was estimated using Global Positioning System devices installed in participants' vehicles. High-range speeding events were defined as traveling an average 10+km/h above the speed limit over 30 seconds. Descriptive analysis examined speeding events by participant characteristics and mileage driven. Regression analyses were used to examine the association between involvement in high-range speeding events and possible predictive factors.

RESULTS

Most (96%, 182/190) participants agreed to have their vehicle instrumented, and speeding events were accurately recorded for 97% (177/182) of participants. While 77% (136/177) of participants were involved in one or more high-range events, 42% (75/177) were involved in greater than five events during 12-months of data collection. Participants involved in high-range events drove approximately twice as many kilometres as those not involved. High-range events tended to be infrequent (median = 6 per 10,000 km; IQR = 2-18). The rate of high-range speeding was associated with better cognitive function and attention to the driving environment.

CONCLUSION

This suggests those older drivers with poorer cognition and visual attention may drive more cautiously, thereby reducing their high-range speeding behavior.

Relationship Between Cognitive Perceptual Abilities and Accident and Penalty Histories Among Elderly Korean Drivers

OBJECTIVE

To investigate the relationship between cognitive perceptual abilities of elderly drivers based on the Cognitive Perceptual Assessment for Driving (CPAD) test and their accident and penalty histories.

METHODS

A total of 168 elderly drivers (aged ≥65 years) participated in the study. Participant data included CPAD scores and incidents of traffic accidents and penalties, attained from the Korea Road Traffic Authority and Korea National Police Agency, respectively.

RESULTS

Drivers' mean age was 70.25±4.1 years and the mean CPAD score was 52.75±4.72. Elderly drivers' age was negatively related to the CPAD score (p<0.001). The accident history group had marginally lower CPAD scores, as compared to the non-accident group (p=0.051). However, incidence rates for traffic fines did not differ significantly between the two groups. Additionally, the group that passed the CPAD test had experienced fewer traffic accidents (3.6%), as compared to the group that failed (10.6%). The older age group (12.0%) had also experienced more traffic accidents, as compared to the younger group (2.4%).

CONCLUSION

Overall, elderly drivers who experienced driving accidents had lower CPAD scores than those who did not, without statistical significance. Thus, driving-related cognitive abilities of elderly drivers with insufficient cognitive ability need to be further evaluated to prevent traffic accidents.

Predictors of older drivers' involvement in rapid deceleration events

Rapid deceleration occurs when substantial force slows the speed of a vehicle. Rapid deceleration events (RDEs) have been proposed as a surrogate safety measure. As there is concern about crash involvement of older drivers and the effect of age-related declining visual and cognitive function on driving performance, we examined the relationship between RDEs and older driver's vision, cognitive function and driving confidence, using naturalistic driving measures. Participants aged 75 to 94 years had their vehicle instrumented for 12 months. To minimise the chance of identifying false positives, accelerometer data was processed to identify RDEs with a substantial deceleration of >750 milli-g (7.35m/s²). We examined the incidence of RDEs amongst older drivers, and how this behaviour is affected by differences in age; sex; visual function, cognitive function; driving confidence; and declines over the 12 months. Almost two-thirds (64%) of participants were involved in at least one RDE, and 22% of these participants experienced a meaningful decline in contrast sensitivity during the 12 months. We conducted regression modelling to examine associations between RDEs and predictive measures adjusted for (i) duration of monitoring and (ii) distance driven. We found the rate of RDEs per distance increased with age; although, this did not remain in the multivariate model. In the multivariate model, we found older drivers who experienced a decline in contrast sensitivity over the 12 months and those with lower baseline driving confidence were at increased risk of involvement in RDEs adjusted for distance driven. In other studies, contrast sensitivity has been associated with increased crash involvement for older drivers. These findings lend support for the use of RDEs as a surrogate safety measure, and demonstrate an association between a surrogate safety measure and a decline in contrast sensitivity of older drivers.

Driving Safety

Driving is a common and hazardous activity that is a prominent cause of death worldwide. Driver behavior represents a predominant cause, contributing to over 90% of crashes. In this review, I will focus on how driver behavior influences driving safety by describing the types of crashes and their general causes, the driving process, the perceptual and cognitive characteristics of drivers, and driver types and impairments. Evidence from each of these perspectives suggests that breakdowns of a multilevel control process are the fundamental factors that undermine driving safety. Drivers adapt and drive safely in a broad range of situations but fail when expectations are violated or when feedback is inadequate. The review concludes by considering driving safety from a societal risk management perspective.

Not all minds wander equally: The influence of traits, states and road environment factors on self-reported mind wandering during everyday driving

Inattention is a road safety problem, but few studies have focused specifically on mind wandering during everyday driving. This paper explores differences in self-reported mind wandering according to driver demographic characteristics (including age and gender), cognitive traits (such as tendency toward cognitive failure or mindful attention), states (such as feeling tired or stressed) and road environment factors (such as route familiarity). Five hundred and two participants (113 male, average age 44.4 years, SD=14.0years) completed a series of questionnaires (Mindful Attention and Awareness Scale (MAAS), Cognitive Failures Questionnaire (CFQ) and Driver Behaviour Questionnaire (DBQ)), as well as study-specific questions about mind wandering during different personal states and across a range of road and traffic situations. All respondents reported mind wandering during driving at least some of the time. Mind wandering was more likely to be reported on familiar roads than on unfamiliar roads and when drivers are tired. Drivers who reported relatively more mind wandering were younger, reported less mindful attention in daily life, more cognitive failures, and more driving violations and lapses. Together, the findings suggest that mind wandering is common in everyday driving, however any link with crash risk remains unclear. Future research using self-report and naturalistic methods could provide more insight into relationships between mind wandering, error and crash risk.

A longitudinal investigation of the predictors of older drivers' speeding behaviour

There is little objective evidence about the extent older drivers' are involved in speeding or factors that may influence this behaviour. Particular concern exists for the increasing number of older drivers with poor or declining cognitive and visual function. This study investigates whether a reduction in speeding forms part of the self-restrictive driving behaviour evident when older drivers experience poor cognitive and visual function. Driving data over 12 months were collected from 182 volunteers aged 75-94years. Driving speed was estimated using Global Positioning System location, and speed limit data was based on a service-provider database. Speed events were defined as driving 1km/h or more, with 3% tolerance, above a single speed limit, averaged over 30s. Almost all participants (99%) were involved in speed events. While, 16-31% of participants experienced a meaningful decline in cognitive or visual function during the 12-months, these declines were not predictive of a change in speed events. Our results indicate speeding behaviour in this age group was highly prevalent, but less so for the oldest drivers whereby the rate of speed events was 7% lower per year older (IRR=0.93, 95%CI=0.89-0.96). Older drivers with worse function were less involved in speed events (unadjusted for distance driven) during 12 months of observation. Weekly distance driven decreased over the year by approximately 0.45km with every week of monitoring for these older drivers. When distance driven was taken into account, decreased function was not predictive of involvement in speed events, indicating the reduction in speed events may be achieved by older drivers with lower function reducing distance driven. These results are important for developing policy to address speeding behaviour of the growing population of older drivers to reduce the incidence of crashes and resulting casualties.

Age-related Differences in Driving: Are Older Drivers More Serial?

A measurement-instrumented car was used to test the hypothesis that older drivers organise their car-controlling movements in a more serial way in order to reduce the momentary mental workload produced by complex traffic situations. Forty-two older drivers (65+, mean age 67.5) and 36 young middle-aged drivers (26-49, mean age 36.8) drove a measurement-instrumented car around a 7.4 km route in normal traffic. The use of car controls (e.g. clutch, brake) was registered by sensors connected to a computer. In the most complex parts of the test route (e.g. during which three or more controls were in use simultaneously), the older drivers tended to use three controls rather than four or more, whereas the younger group had a greater percentage of four or more controls. This percentage was positively related to speed. However, although older drivers drove more slowly in general, in pairs matched for speed, they still drove in a less parallel manner. Irrespective of age, parallel use of controls was positively related to the level of skill as indicated by the amount of cumulated driving experience. The shift towards more serial operation of controls possibly represents an empirical demonstration of a compensatory mechanism allowing older drivers to maintain their level of performance.

License Suspension Revisited: A 3-Year Follow-Up Study of Older Drivers

This 3-year follow-up study addressed changes in health, cognitive functioning, and driving status among 37 older drivers and 37 individually matched controls. Initially, the study group had suspended driver’s licenses due to traffic violations. The in-person follow-up medical and neuropsychological examinations concerned 20 case participants and 22 controls. Mortality tended to be higher with case participants than with controls (p = .085), and there was more dementia or cognitive impairment with case participants (5/37) than with controls (0/37,p = .027). Initially, crash-involved case participants performed consistently worse on measures of cognitive functioning than did controls and noncrashed case participants and showed greater deterioration over time. Compared to controls, more crash-involved drivers had died (p = .019) or had stopped driving (p = .040). Because some older drivers with unsafe driving behavior may be in early phases of dementing processes or serious medical conditions, they should be medically and cognitively assessed.

Driving Cessation and Health in Older Women

To study the association of health and driving cessation in older female drivers, a mail survey was sent to all Finnish women born in 1927 who gave up their driver license at the age of 70 (n = 1,476) and to a corresponding random sample of women who renewed their license at the age of 70 (n = 1,494). The ex-drivers had poorer overall health status than the drivers, but the health conditions related to driving cessation were in general not of the type impairing driving ability but rather decreasing overall well-being and physical mobility. The results suggest that there is a significant number of older women giving up their license while still fit to drive; hence, for many women, driving cessation may imply a voluntary but unnecessary resignation from an active and independent life.

Driver License Renewal for the Elderly: A Case Study

Periodic renewal of driver licenses is an integral part of the driver licensing procedures for most states. Renewal of driver licenses is usually required every 4 years, and many states conduct vision tests before granting renewal. A few states require additional testing, whereas several states have no vision testing or any other examinations at renewal. Still fewer have additional requirements for older drivers. The increasing percentage of older drivers and the visual changes due to aging or disease are also additional concerns. Thus, it was considered important to systematically review current practices regarding license renewal and retesting and identify potential changes in these procedures. For older drivers, a more frequent renewal period is proposed, accompanied by a vision screening and a medical questionnaire to determine physical and mental status of older drivers.

Potentially Unsafe Activities and Living Conditions of Older Adults with Dementia

OBJECTIVES

To examine the prevalence of dementia in the absence of a reported dementia diagnosis and whether potentially unsafe activities and living conditions vary as a function of dementia diagnosis status in a nationally representative sample of older adults.

DESIGN

Observational cohort study.

SETTING

Community.

PARTICIPANTS

Medicare beneficiaries aged 65 and older enrolled in the National Health and Aging Trends Study (N = 7,609).

MEASUREMENTS

Participants were classified into four groups based on self-report of dementia diagnosis, proxy screening interview, and cognitive testing: probable dementia with reported dementia diagnosis (n = 457), probable dementia without reported dementia diagnosis (n = 581), possible dementia (n = 996), or no dementia (n = 5,575). Potentially unsafe activities (driving, preparing hot meals, managing finances or medications, attending doctor visits alone) and living conditions (falls, living alone, and unmet needs) were examined according to dementia status subgroups in stratified analyses and multivariate models, adjusting for sociodemographic factors, medical comorbidities, and physical capacity.

RESULTS

The prevalence of driving (22.9%), preparing hot meals (31.0%), managing finances (21.9%), managing medications (36.6%), and attending doctor visits alone (20.6%) was lowest in persons with probable dementia; however, but in persons with probable dementia, the covariate-adjusted rates of driving, preparing hot meals, managing finances, managing medications, and attending doctor visits alone were significantly higher in those without reported dementia diagnosis than in those with reported diagnosis (all odds ratios ≥2.00, all P < .01).

CONCLUSION

Older adults with probable dementia who are not aware of a dementia diagnosis are more likely to report engaging in potentially unsafe behaviors. Understanding the prevalence of potentially unsafe activities and living conditions can help clinicians focus safety screening and counseling in older adults with diagnosed or suspected dementia.

Neurocognitive Correlates of Young Drivers' Performance in a Driving Simulator

PURPOSE

Differences in neurocognitive functioning may contribute to driving performance among young drivers. However, few studies have examined this relation. This pilot study investigated whether common neurocognitive measures were associated with driving performance among young drivers in a driving simulator.

METHODS

Young drivers (19.8 years (standard deviation [SD] = 1.9; N = 74)) participated in a battery of neurocognitive assessments measuring general intellectual capacity (Full-Scale Intelligence Quotient, FSIQ) and executive functioning, including the Stroop Color-Word Test (cognitive inhibition), Wisconsin Card Sort Test-64 (cognitive flexibility), and Attention Network Task (alerting, orienting, and executive attention). Participants then drove in a simulated vehicle under two conditions-a baseline and driving challenge. During the driving challenge, participants completed a verbal working memory task to increase demand on executive attention. Multiple regression models were used to evaluate the relations between the neurocognitive measures and driving performance under the two conditions.

RESULTS

FSIQ, cognitive inhibition, and alerting were associated with better driving performance at baseline. FSIQ and cognitive inhibition were also associated with better driving performance during the verbal challenge. Measures of cognitive flexibility, orienting, and conflict executive control were not associated with driving performance under either condition.

CONCLUSIONS

FSIQ and, to some extent, measures of executive function are associated with driving performance in a driving simulator. Further research is needed to determine if executive function is associated with more advanced driving performance under conditions that demand greater cognitive load.

Driving Trail Making Test part B: a variant of the TMT-B

[Purpose] The Trail Making Test part B (TMT-B) is used in evaluating driving abilities and includes testing for the executive function. A driving simulator version of this test (DTMT-B) was developed to measure drivers’ executive abilities in three-dimensional space. The purpose of the present study was to assess the validity of the DTMT-B for driving assessment. [Subjects] Thirty stroke patients and 65 healthy subjects were recruited. [Methods] Participants performed the TMT-B and DTMT-B. The DTMT-B was run on a driving simulator in which the individual performed a task on virtual roads connecting the lettered and numbered TMT-B points by simulated driving instead of connecting them with lines as in the paper or computerized TMT-B. Intra-class correlation coefficients (ICCs) were used to assess validities. Significant correlations were found between the TMT-B and DTMT-B. [Results] Participants performed the TMT-B and DTMT-B. Intra-class correlation coefficients (ICCs) were used to assess validities. Significant correlations were found between the TMT-B and DTMT-B. [Conclusion] The results suggest that the DTMT-B may be useful as part of driver screening assessment using a driving simulator for stroke patients and that it may also be used to assess the executive functions for healthy people.

Motor Output Variability Impairs Driving Ability in Older Adults

BACKGROUND

The functional declines with aging relate to deficits in motor control and strength. In this study, we determine whether older adults exhibit impaired driving as a consequence of declines in motor control or strength.

METHODS

Young and older adults performed the following tasks: (i) maximum voluntary contractions of ankle dorsiflexion and plantarflexion; (ii) sinusoidal tracking with isolated ankle dorsiflexion; and (iii) a reactive driving task that required responding to unexpected brake lights of the car ahead. We quantified motor control with ankle force variability, gas position variability, and brake force variability. We quantified reactive driving performance with a combination of gas pedal error, premotor and motor response times, and brake pedal error.

RESULTS

Reactive driving performance was ~30% more impaired (t = 3.38; p < .01) in older adults compared with young adults. Older adults exhibited greater motor output variability during both isolated ankle dorsiflexion contractions (t = 2.76; p < .05) and reactive driving (gas pedal variability: t = 1.87; p < .03; brake pedal variability: t = 4.55; p < .01). Deficits in reactive driving were strongly correlated to greater motor output variability (R ² = .48; p < .01) but not strength (p > .05).

CONCLUSIONS

This study provides novel evidence that age-related declines in motor control but not strength impair reactive driving. These findings have implications on rehabilitation and suggest that interventions should focus on improving motor control to enhance driving-related function in older adults.

Neuropsychological Correlates of Hazard Perception in Older Adults

OBJECTIVES

Hazard perception, the ability to identify and react to hazards while driving, is of growing importance in driving research, given its strong relationship to real word driving variables. Furthermore, although poor hazard perception is associated with novice drivers, recent research suggests that it declines with advanced age. In the present study, we examined the neuropsychological correlates of hazard perception in a healthy older adult sample.

METHODS

A total of 68 adults age 60 and older who showed no signs of dementia and were active drivers completed a battery of neuropsychological tests as well as a hazard perception task. Tests included the Repeatable Battery for the Assessment of Neuropsychological Status, Wechsler Test of Adult Reading, Trail Making Test, Block Design, Useful Field of View, and the Delis-Kaplan Executive Function System Color Word Interference Test.

RESULTS

Hazard perception errors were related to visuospatial/constructional skills, processing speed, memory, and executive functioning skills, with a battery of tests across these domains accounting for 36.7% of the variance in hazard perception errors. Executive functioning, particularly Trail Making Test part B, emerged as a strong predictor of hazard perception ability.

CONCLUSIONS

Consistent with prior work showing the relationship of neuropsychological performance to other measures of driving ability, neuropsychological performance was associated with hazard perception skill. Future studies should examine the relationship of neuropsychological changes in adults who are showing driving impairment and/or cognitive changes associated with Mild Cognitive Impairment or dementia.

Neurocognitive Recovery After Hospital-Treated Deliberate Self-Poisoning With Central Nervous System Depressant Drugs: A Longitudinal Cohort Study

Hospital-treated deliberate self-poisoning (DSP) by central nervous system depressant drugs (CNS-D) has been associated with impairments in cognitive and psychomotor functions at the time of discharge. We aimed to replicate this finding and to compare recovery in the first month after discharge for CNS-D and CNS nondepressant drug ingestions. We also examined a series of multivariate explanatory models of recovery of neurocognitive outcomes over time. The CNS-D group was impaired at discharge compared with the CNS-nondepressant group in cognitive flexibility, cognitive efficiency, and working memory. There were no significant differences at discharge in visual attention, processing speed, visuomotor speed, or inhibition speed. Both groups improved in the latter measures over 1 month of follow-up. However, the CNS-D group's recovery was significantly slower for key neurocognitive domains underlying driving in complex traffic situations, namely, cognitive flexibility, cognitive efficiency, and working memory. Patients discharged after DSP with CNS-D drugs have impairments of some critical cognitive functions that may require up to 1 month to recover. Although more pre- than post-DSP variables were retained as explanatory models of neurocognitive performance overall, recovery over time could not be explained by any one of the measured covariates. Tests of cognitive flexibility could be used in clinical settings as a proxy measure for recovery of driving ability. Regulatory authorities should also consider the implications of these results for the period of nondriving advised after ingestion of CNS-D in overdose. Future research, with adequate sample size, should examine contributions of other variables to the pattern of recovery over time.

Mobility and safety issues in drivers with dementia

Although automobiles remain the mobility method of choice for older adults, late-life cognitive impairment and progressive dementia will eventually impair the ability to meet transport needs of many. There is, however, no commonly utilized method of assessing dementia severity in relation to driving, no consensus on the specific types of assessments that should be applied to older drivers with cognitive impairment, and no gold standard for determining driving fitness or approaching loss of mobility and subsequent counseling. Yet, clinicians are often called upon by patients, their families, health professionals, and driver licensing authorities to assess their patients' fitness-to-drive and to make recommendations about driving privileges. We summarize the literature on dementia and driving, discuss evidenced-based assessments of fitness-to-drive, and outline the important ethical and legal concerns. We address the role of physician assessment, referral to neuropsychology, functional screens, dementia severity tools, driving evaluation clinics, and driver licensing authority referrals that may assist clinicians with an evaluation. Finally, we discuss mobility counseling (e.g. 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.

Participating in mobility: People with schizophrenia driving motorized vehicles

Participation of people with schizophrenia in individual mobility is an important aspect of inclusion according to the UN convention of human rights of persons with disabilities. However, driving motorized vehicles can be dangerous due to positive, negative, and cognitive symptoms, side effects of antipsychotic drugs and concomitant substance abuse. The objective of this study was to explore the patterns of individual mobility in a representative patient population, to determine predictors for active use of motorized vehicles, and to compare the results with data of the general population in the respective region. We interviewed N=150 participants with schizophrenia or schizoaffective disorder, 66 in-patients and 84 out-patients, in different types of out-patient services. A questionnaire developed for this purpose was used in interviews. 64% of the participants had a driving licence, 32% had driven a motorized vehicle in the past year, 31% owned a car, 2% a motor bike. The driving licence had been withdrawn from 24.7% of participants, 32.7% reported having been involved in a road accident. Participants drove considerably less in time and distances than the general population. Significant variables determining the chance of active use of motorized vehicles in a logistic regression model were Global Assessment of Functioning (GAF) (OR 1.04 per each point), number of previous admissions (OR 0.52 per admission), and history of driving under alcohol or drugs (OR 0.18).

DriveSafe and DriveAware Assessment Tools Are a Measure of Driving-Related Function and Predicts Self-Reported Restriction for Older Drivers

Safety concerns together with aging of the driving population has prompted research into clinic-based driving assessments. This study investigates the relationship between the DriveSafe and DriveAware assessments and restriction of driving. Community-dwelling adults aged more than 75 ( n = 380) were recruited in New South Wales, Australia. Questionnaires were administered to assess driving habits and functional assessments to assess driving-related function. Self-reported restriction was prevalent in this cross-sectional sample (62%) and was related to DriveSafe scores and personal circumstances but not DriveAware scores. DriveSafe scores were correlated with better performance on the Trail-Making Test (TMT; β = −2.94, p < .0001) and better contrast sensitivity (β = 48.70, p < .0001). Awareness was associated with better performance on the TMT (β = 0.08, p < .0001). Our data suggest that DriveSafe and DriveAware are sensitive to deficits in vision and cognition, and drivers with worse DriveSafe scores self-report restricting their driving.