Date Presented 04/07/19
This prospective study determined the driving errors underlying a strategic driving maneuver that validly predicted passing versus failing an on-road assessment in drivers with multiple sclerosis (MS). Study findings indicate that through lane maintenance or speed regulation errors, the strategic driving maneuver may supplement on-road driving performance to help determine pass versus fail outcomes in drivers with MS.
Primary Author and Speaker: Sarah Krasniuk
Contributing Authors: Sherrilene Classen, Sarah Morrow
PURPOSE: Persons with Multiple Sclerosis (PwMS) with higher-order cognitive impairment may commit driving errors underlying strategic driving maneuvers. Strategic driving maneuvers require higher-order cognitive function to assess, initiate, plan, reason, decide, and problem-solve when preparing or navigating routes to reach goal-directed destinations (Michon, 1985). Previously, we found that adjustment to stimuli and gap acceptance errors validly predict 92% of on-road outcomes in PwMS (Krasniuk et al., 2017). However, we do not understand the driving errors of strategic driving maneuvers in the MS population. Understanding such driving errors may elucidate on-road decisions for PwMS. The purpose of this study is to determine the driving errors underlying a strategic driving maneuver that validly predict PwMS passing vs. failing the on-road assessment.
DESIGN: This prospective study obtained ethics approval from the institutions’ research ethics boards. We recruited community-dwelling PwMS from MS Clinics in London, Canada. Participants (M age=50 years) included 35 licensed drivers with a physician-verified diagnosis of MS and low physical disability, but cognitive impairment in processing speed and one of either memory or executive function (Morrow et al., 2017).
METHOD: All participants completed the Minimal Assessment of Cognitive Function in MS and Useful Field of View™. A licensed driving instructor and occupational therapist certified driver rehabilitation specialist jointly administered the on-road assessment, incorporating the strategic driving maneuver, with excellent inter-rater reliability and construct validity (Classen et al., 2016). The strategic driving maneuver included a navigational task requiring participants to select a route from several alternatives varying in task difficulty to reach the goal-directed destination. Descriptive statistics and Wilcoxon rank-sum tests determined significant differences in clinical assessments and driving errors between PwMS who passed vs. failed the on-road assessment. Bivariate Spearman rho correlations determined the magnitude and direction of relationships between clinical assessments and significant driving errors. Logistic regression and receiver operating characteristic curve analyses determined the predictive validity of significant driving errors on pass vs. fail outcomes.
RESULTS: No clinical assessments differed between PwMS who passed (n=28) vs. failed (n=7) the on-road assessment. PwMS who failed (vs. passed) made significantly more lane maintenance (M=1.1 vs. .3, p=.02), and speed regulation errors (M=.7 vs. .04, p=.03) in the strategic driving maneuver. Poorer long-term visuospatial memory moderately correlated with more speed regulation errors (ρ=-.37,p=.03). Two final regression models indicated that lane maintenance errors (OR=.18, p=.009, CI=[.05, .66]) and speed regulation errors (OR=.04, p=.009, CI=[.003, .44]) solely predicted pass vs. fail outcomes in PwMS. Optimal cut-points >1 for lane maintenance (AUC=.78, p=.02; 71% sensitivity, 79% specificity, 45% positive and 92% negative predictive values, 23% misclassified) and speed regulation errors (AUC=.77, p=.03; 57% sensitivity, 96% specificity, 80% positive and 90% negative predictive values, 11% misclassified) validly predicted on-road outcomes.
CONCLUSION: We concluded that, through lane maintenance or speed regulation errors, the strategic driving maneuver may supplement on-road driving performance to help determine pass vs. fail outcomes in PwMS. Type II error may exist for some non-significant findings due to the small sample size and not having adequate power to detect significant differences. Further research may compare study findings in an adequately-powered sample of PwMS vs. control group.
References
Classen, S., Krasniuk, S., Alvarez, L., Monahan, M., Morrow, S. A., & Danter, T. (2017). Development and validity of Western University’s On-Road Assessment. OTJR: Occupation, Participation & Health, 37, 14-29. doi: 10.1177/1539449216672859
Krasniuk, S., Classen, S., Morrow, S. A., Miriam, M., Danter, T., Rosehart, H., & Wenqing, He. (2017). Driving errors that predict on-road outcomes in adults with Multiple Sclerosis. OTJR: Occupation, Participation and Health, 37(3), 115-124. doi: 10.1177/1539449217708554
Michon, J. A. (1985). A critical view of driver behavior models: What do we know, what should we do? In E. L. Evans & R. Schwing (Eds.), Human Behavior and Traffic Safety (pp. 485-520). New York: Plenum.
Morrow, S. A., Classen, S., Monahan, M., Danter, T., Taylor, R., Krasniuk, S., Rosehart, H., & He, W. (2017). On-road assessment of fitness to drive in persons with MS with cognitive impairment: A Prospective study. Multiple Sclerosis Journal, Online First, 1-8. doi: 10.1177/1352458517723991
