Sandra M. Winter

Evidence-based review on epilepsy and driving.

OBJECTIVE The aim of this study was to synopsize the evidence on predictors of crashes and driving status in people with epilepsy (PWE). METHODS Evidence-based review of the published English literature was the method used. We searched various databases and extracted data from 16 (of 77) primary studies. On the basis of American Academy of Neurology criteria, we assigned each study a class of evidence (I-IV, where I indicates the highest level of evidence) and made recommendations (Level A: predictive or not; Level B: probably predictive or not; Level C: possibly predictive or not; Level U: no recommendations). RESULTS For PWE, the following characteristics are considered useful: For identifying crash risk, epilepsy (level B) and short seizure-free intervals (≥3 months) (Level C) are not predictive of motor vehicle crash (MVC). For self/proxy-reported crash risk, epilepsy surgery (Level B), seizure-free intervals (6-12 months) (Level B), few prior non-seizure-related crashes (Level B), and regular antiepileptic drug adjustments (Level B) are protective against crashes; seizures contribute to MVCs (Level C); mandatory reporting does not contribute to reduced crashes (Level C). No recommendations for reliable auras, age, and gender (Level U), as data are inadequate to make determinations. For self-reported driving or licensure status, employment and epilepsy surgery are predictive of driving (Level C); there are no recommendations for antiepileptic drug use, self-reported driving, gender, age, receiving employment benefits, or having reduced seizure frequency (Level U). CONCLUSION Limitations, that is, heterogeneity among studies, examining the English literature from 1994 to 2010, must be considered. Yet, this is the first evidence-based review to synopsize the current PWE and driving literature and to provide recommendation(s) to clinicians and policy makers. Class I studies, matched for age and gender, yielding Level A recommendations are urgently needed to define the risks, benefits, and causal factors underlying driving performance issues in PWE.

Predicting older driver on-road performance by means of the useful field of view and trail making test part B

The Useful Field of View(®) (UFOV) and Trail Making Test Part B (Trails B) are measures of divided attention. We determined which measure was more accurate in predicting on-road outcomes among drivers (N = 198, mean age = 73.86, standard deviation = 6.05). Receiver operating characteristic curves for the UFOV (Risk Index [RI] and Subtests 1-3) and Trails B significantly predicted on-road outcomes. Contrasting Trails B with the UFOV RI and subtests, the only difference was found between the UFOV RI and Trails B, indicating the UFOV RI was the best predictor of on-road outcomes. Misclassifications of drivers totaled 28 for the UFOV RI, 62 for Trails B, and 58 for UFOV Subtest 2. The UFOV RI is a superior test in predicting on-road outcomes, but the Trails B has acceptable accuracy and is comparable to the other UFOV subtests.

MMSE as a predictor of on-road driving performance in community dwelling older drivers.

Screening tools such as the MMSE have been used extensively in driving research studies to determine mild cognitive impairment or dementia. While some studies have shown the MMSE to correlate with driving performance, few studies have shown the predictive validity of the MMSE in determining on-road performance. In a sample of 168 community dwelling older adults, including 20 with Parkinsons disease (PD), the primary objective was to determine the validity of the MMSE to predict pass/fail outcomes of an on-road driving test using receiver operating characteristics curves. The area under the curve (AUC), an index of discriminability, for the total sample was .654, 95% CI=0.536-0.772, p=.009. Meanwhile, the AUC for the PD group was 0.791, 95% CI=0.587-0.996, p=.036. The total sample showed statistically significant yet poor predictive validity. However, the PD group showed statistically significant and good predictive validity of the MMSE to predict pass/fail outcomes on the road test, but caution is warranted as the confidence intervals are wide (due to small sample) and the positive and negative predictive values are less than desirable due to the associated error. The findings show that using the current cut-off point of ≤24 on the MMSE is not adequately sensitive to predict on-road performance in both community dwelling older drivers and in drivers with PD. This study offers strong evidence to support the current best practice of not using the MMSE in isolation to predict on-road performance.

Gender differences among older drivers in a comprehensive driving evaluation

Research studies typically consider older drivers as a homogenous group and do not report on the influence of gender on driving performance. Prior studies report that females are over-represented in crashes compared to males, caused by errors of yielding, gap acceptance, and speed regulation, all of which are assessed in a comprehensive driving evaluation (CDE). In a sample of 294 community dwelling older drivers, we examined and compared specific and total driving errors of both genders, and determined predictors of gender-specific driving errors and pass/fail outcomes who completed a CDE assessed by a certified driving rehabilitation specialist. No differences in specific or total number of driving errors on the CDE were found between older males (Mean age 73.4±6.0) and older females (Mean age 73.8±5.7). Education, days of driving, Useful Field of View™ (UFOV), Rapid Paced Walk Test (RPW) and the Mini-Mental State Exam (MMSE) were all independent predictors of failing a road test for both genders (p<0.05). However, older females were 22% less likely than older males to fail an on-road test. Within group comparisons showed that older males and females >75 years were 3.2 and 3.5 times more likely to fail the on-road test compared to younger males and females (aged between 63 and 75), respectively. Our findings suggest that focusing on older old (75+) and old-old (85+) age groups may be more efficient for future investigations of driving performance.

Psychometrics of the self-report safe driving behavior measure for older adults.

We investigated the psychometric properties of the 68-item Safe Driving Behavior Measure (SDBM) with 80 older drivers, 80 caregivers, and 2 evaluators from two sites. Using Rasch analysis, we examined unidimensionality and local dependence; rating scale; item- and person-level psychometrics; and item hierarchy of older drivers, caregivers, and driving evaluators who had completed the SDBM. The evidence suggested the SDBM is unidimensional, but pairs of items showed local dependency. Across the three rater groups, the data showed good person (≥3.4) and item (≥3.6) separation as well as good person (≥.93) and item reliability (≥.92). Cronbachs α was ≥.96, and few items were misfitting. Some of the items did not follow the hypothesized order of item difficulty. The SDBM classified the older drivers into six ability levels, but to fully calibrate the instrument it must be refined in terms of its items (e.g., item exclusion) and then tested among participants of lesser ability.

Literature Review on Older Adult Gender Differences for Driving Self-regulation and Cessation

Researchers are calling for increased studies with regard to differences between older men and women drivers. This literature review focuses on gender comparisons for self-regulation of driving and driving cessation. We reviewed 20 articles and assigned levels of evidence. Seven studies were level II (eg, prospective cohort) and 13 were level III (eg, cross-sectional). Subsequently, 5 evidence-based recommendations were made to address gender-specific needs of older men and women. Additional research is needed to clarify gender patterns for self-regulation and cessation and increase the level of evidence supporting gender-specific driving interventions.

Associations between clinical tests and simulated driving performance in persons with epilepsy

People with epilepsy (PWE) may experience seizures that constitute a risk to road safety. Consequently, many states have instituted restrictions, such as being seizure-free for intervals of 3 to 12 months, before driving can be resumed. However, 30% of drivers with recurrent seizures still drive despite having a restricted license. As a result of recurrent and uncontrolled seizures, PWE may have impairments in motor, visual and cognitive abilities, as well as impaired driving performance. No studies to date have prospectively examined factors associated with driving performance in PWE. The primary objective of this study was to determine which tests, from a clinical battery, are correlated with driving errors in PWE using a simulator. The sample consisted of 16 drivers with epilepsy (mean age 44.3±12.0; 63% women) recruited from the epilepsy monitoring unit at the University of Florida. All participants completed a clinical battery of cognitive, visual and motor tests, as well as a 35-minute drive on a simulator. Significant correlations emerged between: visual acuity with visual scanning (r=.69, p<.01) and adjustment to stimuli (r=.60, p<.05); contrast sensitivity with lane maintenance (r=-.54, p>.05), vehicle position (r=-.61, p>.05) and total number of errors (r=-.72, p>.01); and useful field of view scores (subtest 2) with visual scanning (r=.57, p>.05) and vehicle position (r=.63, p>.05). Limitations and future implications are addressed. The preliminary findings suggest visual and visual-cognitive tests are associated with driving errors in a simulated driving environment.

Systematic Literature Review and Model for Older Driver Safety

Using the Precede-Proceed Model of Health Promotion (PPMHP) and an etiological systematic literature review, we examined the risk/protective factors of older driver safety in the United States. We described key features of this literature review and developed a structural model illustrating the prevalence of risk/protective factors in the health domain (63%) and in other PPMHP domains (environment 20%; behavior and lifestyle 10%; predisposing 1%; reinforcing 3%, enabling 2%; health education 2%). This model, a first step in synopsizing and quantifying these risk/protective factors, informs rehabilitation professionals of their etiology and prevalence, affords opportunities for multidisciplinary research, and lays the foundation for intervention planning.

Utility of an occupational therapy driving intervention for a combat veteran

Many combat veterans are injured in motor vehicle crashes shortly after returning to civilian life, yet little evidence exists on effective driving interventions. In this single-subject design study, we compared clinical test results and driving errors in a returning combat veteran before and after an occupational therapy driving intervention. A certified driving rehabilitation specialist administered baseline clinical and simulated driving assessments; conducted three intervention sessions that discussed driving errors, retrained visual search skills, and invited commentary on driving; and administered a postintervention evaluation in conditions resembling those at baseline. Clinical test results were similar pre- and postintervention. Baseline versus postintervention driving errors were as follows: lane maintenance, 23 versus 7; vehicle positioning, 5 versus 1; signaling, 2 versus 0; speed regulation, 1 versus 1; visual scanning, 1 versus 0; and gap acceptance, 1 versus 0. Although the intervention appeared efficacious for this participant, threats to validity must be recognized and controlled for in a follow-up study.

Psychometrics of the Fitness-to-Drive Screening measure

We employed item response theory (IRT), specifically using Rasch modeling, to determine the measurement precision of the Fitness-to-Drive Screening Measure (FTDS), a tool that can be used by caregivers and occupational therapists to help detect at-risk drivers. We examined unidimensionality through the factor structure (how items contribute to the central construct of fitness to drive), rating scale (use of the categories of the rating scale), item/person-level separation (distinguishing between items with different difficulty levels or persons with different ability levels) and reliability, item hierarchy (easier driving items advancing to more difficult driving items), rater reliability, rater effects (severity vs. leniency of a rater), and criterion validity of the FTDS to an on-road assessment, via three rater groups (n = 200 older drivers; n = 200 caregivers; n = 2 evaluators). The FTDS is unidimensional, the rating scale performed well, has good person (>3.07) and item (>5.43) separation, good person (>0.90) and item reliability (>0.97), with <10% misfitting items for two rater groups (caregivers and drivers). The intraclass correlation (ICC) coefficient among the three rater groups was significant (.253, p < .001) and the evaluators were the most severe raters. When comparing the caregivers’ FTDS rating with the drivers’ on-road assessment, the areas under the curve (index of discriminability; caregivers .726, p < .001) suggested concurrent validity between the FTDS and the on-road assessment. Despite limitations, the FTDS is a reliable and accurate screening measure for caregivers to help identify at-risk older drivers and for occupational therapy practitioners to start conversations about driving.