Lynnette Kay

Predicting Fitness to Drive in People With Cognitive Impairments by Using DriveSafe and DriveAware

OBJECTIVES To examine the psychometric properties of DriveSafe and DriveAware and their predictive validity. DESIGN Prospective study compared screening tests with criterion standard. SETTING Two driving rehabilitation centers affiliated with a university and a geriatric rehabilitation facility. PARTICIPANTS Consecutive sample of drivers with functional impairments (n=115) and subgroup of drivers with cognitive impairments (n=96) referred for a driving assessment. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURE Driving performance was measured by a standardized assessment in real traffic. RESULTS Rasch analysis provided evidence for construct validity and internal reliability of both tests. Tests trichotomized drivers into unsafe, safe, and further testing categories. The optimal lower cutoff identified unsafe drivers with a specificity of 97% (95% confidence interval [CI], 83-100) in the test sample and 96% (95% CI, 80-100) in the validation sample. The optimal upper cutoff identified safe drivers with a sensitivity of 93% (95% CI, 77-99) and 95% (95% CI, 76-100), respectively. CONCLUSIONS By using DriveSafe and DriveAware, drivers with cognitive impairments referred for a driving assessment can be categorized as unsafe, safe, or requiring further testing, with only 50% needing an on-road assessment. Before clinical practice is changed, these findings should be replicated.

Validity and reliability of the on-road driving assessment with senior drivers.

The on-road driving assessment is widely regarded as the criterion measure for driving performance despite a paucity of evidence concerning its psychometric properties. The purpose of this study was 2-fold. First, we examined the psychometric properties of an on-road driving assessment with 100 senior drivers between 60 and 86 years (80 healthy volunteers and 20 with specific vision deficits) using Rasch modeling. Second, we compared the outcome of the gestalt decision made by trained professionals with that based on weighted error scores from the standardized assessment. Rasch analysis provided good evidence for construct validity and inter-rater reliability of the on-road assessment and some evidence for internal reliability. Goodness of fit statistics for all items were within an acceptable range and the item hierarchy was logical. The test had a moderate reliability index (0.67). The best cut off score yielded sensitivity of 81% and specificity of 95% compared with the gestalt decision. Further research is required with less competent drivers to more fully examine reliability. Healthy senior drivers failed to check blind spots when changing lanes and made errors when asked to report road markings and traffic signs as they drove. In addition unsafe drivers had difficulty negotiating intersections and lane changes.

Contribution of off-road tests to predicting on-road performance: A critical review of tests

BACKGROUND/AIM Driving is an essential activity of daily living. Because it is easily disrupted by illness or injury, it is a common subject of occupational therapy assessment. Assessments of driving are critically important and carry legal implications for therapists. A full occupational therapy assessment comprising both off- and on-road testing is time and labour intensive and therefore expensive. Off-road tests are used to inform on-road assessments, and, if they have sufficient sensitivity and specificity they may replace an on-road assessment for some clients. The twofold purpose of this article is to compare and critique off-road tests to predict driving performance and to determine if any is sufficiently accurate to identify drivers who do not require an on-road assessment. METHODS We reviewed tests commonly used by researchers to predict driving capacity (i) that have been used in research since 2000 and (ii) for which sensitivity and specificity had been (or could be) calculated. We compared the tests on five characteristics: diagnostic makeup of samples, sample sizes, outcome measures, sensitivity and specificity and potential for use as a supplement to on-road assessment or to identify drivers for whom an on-road assessment is not necessary. RESULTS AND CONCLUSIONS No gold standard off-road test exists for predicting on road performance. DriveSafe/DriveAware and SMC Tests had the highest reported sensitivity and specificity. Thus, with further research, one or both may be found to predict on-road performance accurately and to minimise the need for on road assessment. Several other tests are a useful supplement to on-road testing.

Validity, reliability and predictive accuracy of the Driving Awareness Questionnaire

Purpose. To examine the psychometric properties of the Driving Awareness Questionnaire (DriveAware) and to compare this rating of awareness of driving ability with the rating made in the context of an on-road assessment. Method. A prospective design was employed to examine the psychometric properties of DriveAware using Rasch analysis. Participants (n = 91) with varying diagnoses were recruited from two driving rehabilitation centres in Sydney, Australia. They completed DriveAware in the context of a standard driving assessment. Awareness of driving ability determined by DriveAware was compared with awareness determined in the on-road assessment. Results. Rasch analysis provided good evidence for construct validity and inter-rater reliability and some evidence for internal reliability of DriveAware. The item hierarchy was logical and goodness-of-fit statistics for four of five items were within an acceptable range. The test had a moderate reliability index (0.73). Measurement precision could be improved by including more items to assess drivers with little awareness. When compared with the on-road measure of awareness, the best DriveAware cut-off score yielded sensitivity of 84% and specificity of 94%. Conclusion. This short and easy-to-administer test could provide a useful tool with sound psychometric properties to measure awareness of driving ability.

Current licensing authority standards for peripheral visual field and safe on-road senior aged automobile driving performance

Background:  The current licensing authoritys (Austroads) visual field standards are met when a person demonstrates an intact visual field extending horizontally at least 120 degrees within 10 degrees above and below the horizontal midline. A person cannot be licensed unconditionally if they have a hemianopia, quadrantanopia or any significant visual field loss (scotoma) that is likely to impede driving performance. Despite fairly rigorous implementation of these vision standards by licensing authorities, there is little scientific evidence available to demonstrate that a driver will or will not be safe on road depending on the extent of their visual field.