Driving environments that influence on-road outcomes in persons with Multiple Sclerosis

IntroductionDrivers with Multiple Sclerosis (MS) who demonstrate adjustment to stimuli and gap acceptance errors may be prone to fail a standardized on-road assessment. However, the complexity (e.g., traffic speed, volume of road users, flow of traffic, spaced interchanges) of driving environments, and their relationship to driving errors critical for failing, is not fully understood. This prospective research study determines the predictive validity of the total number of adjustment to stimuli and gap acceptance errors (modelled as one variable) in residential, suburban, city, or highway environments on drivers with MS failing (vs. passing) a standardized on-road assessment.MethodsCommunity-dwelling participants with MS (N = 35) completed a comprehensive driving evaluation consisting of clinical and on-road assessments, adhering to the regulations for assessing fitness to drive in Ontario, Canada.ResultsLogistic regression models indicated that, as sole predictors, the total number of adjustment to stimuli and gap acceptance errors made in suburban (OR = 0.43, 95% CI = 0.23, 0.83], p = .012) and city environments (OR = 0.34, 95% CI = 0.13, 0.89], p = .028) significantly increased the odds of participants failing the on-road assessment. Also, the total number of adjustment to stimuli and gap acceptance errors made in suburban (AUC = 0.84, SE = 0.11, p = .006, 95% CI = 0.63, 1.00]) and city environments (AUC = 0.74, SE = 0.12, p = .05, 95% CI = 0.51, 0.98]) predicted on-road outcomes. A cut-point of 4 or more adjustment to stimuli and gap acceptance errors made in suburban environments optimally predicted on-road outcomes with 71.4% sensitivity, 92.9% specificity, and 4 misclassifications; while a cut-point of 2 or more adjustment to stimuli and gap acceptance errors made in city environments optimally predicted on-road outcomes with 57.1% sensitivity, 92.9% specificity, and 5 misclassifications.ConclusionThe total number of adjustment to stimuli and gap acceptance errors made in suburban and city environments predict drivers with MS failing a standardized on-road assessment. Assessing adjustment to stimuli and gap acceptance errors in these environments are critical for informing fitness to drive decisions.