On-road assessment of fitness-to-drive in persons with MS with cognitive impairment: A prospective study.

BACKGROUND: Cognitive impairment is common in multiple sclerosis (MS). In other populations, cognitive impairment is known to affect fitness-to-drive. Few studies have focused on fitness-to-drive in MS and no studies have solely focused on the influence of cognitive impairment. OBJECTIVE: To assess fitness-to-drive in persons with MS with cognitive impairment and low physical disability. METHODS: Persons with MS, aged 18-59 years with EDSS ⩽ 4.0, impaired processing speed, and impairment on at least one measure of memory or executive function, were recruited. Cognition was assessed using the Minimal Assessment of Cognitive Function battery. A formal on-road driving assessment was conducted. Chi-square analysis examined the association between the fitness-to-drive (pass/fail) and the neuropsychological test results (normal/impaired). Bayesian statistics predicting failure of the on-road assessment were calculated. RESULTS: Of 36 subjects, eight (22.2%) were unfit to drive. Only the BVMTR-IR, measuring visual-spatial memory, predicted on-road driving assessment failure ( X2 ( df = 1, N = 36) = 3.956; p = 0.047) with a sensitivity of 100%, but low specificity (35.7%) due to false positives (18/25). CONCLUSION: In persons with MS and impaired processing speed, impairment on the BVMTR-IR should lead clinicians to address fitness-to-drive.

Visual Correlates of Fitness to Drive in Adults With Multiple Sclerosis.

The impact of visual and visual-cognitive impairments on fitness to drive in persons with multiple sclerosis (PwMS) are not well studied. We quantified visual correlates of fitness to drive in 30 PwMS. PwMS completed visual ability and visual attention assessments, and a standardized on-road assessment, and were compared with 145 older volunteer drivers. PwMS (vs. older volunteer drivers) made more total ( W = 12,139, p = .03) and critical driving errors (predictive of crashes) in adjustment to stimuli ( W = 11,352, p < .0001), vehicle positioning ( W = 11,449, p < .0001), and wide lane turns ( W = 9,932, p < .0001). PwMS who failed (vs. passed) made more total ( W = 325, p = .04), adjustment to stimuli ( W = 321.5, p = .02), and gap acceptance errors ( W = 333, p = .03). For PwMS, adjustment to stimuli errors moderately correlated with visual acuity (ρ = .50, p = .006), and gap acceptance errors moderately correlated with visual processing speed (ρ = .40, p = .03). Visual-cognitive impairments may be indicative of critical driving errors and help identify PwMS at-risk for fitness to drive.

Driving Errors That Predict On-Road Outcomes in Adults With Multiple Sclerosis.

Driving errors that predict on-road outcomes for persons with multiple sclerosis (PwMS) are not well studied. The objective of this study was to determine whether adjustment-to-stimuli and gap acceptance errors significantly predict passing/failing a standardized on-road assessment of PwMS. Thirty-seven participants completed visual ability and visual attention assessments, and participated in an on-road assessment, where seven types of driving errors and pass/fail outcomes were determined. Adjustment-to-stimuli (No.) and gap acceptance errors (commit/did not commit) significantly predicted passing/failing the on-road assessment, with an area under the curve of 91.6% ( p < .0001). With no gap acceptance errors committed, five adjustment-to-stimuli errors optimally determined pass/fail outcomes in PwMS. Furthermore, with no adjustment to stimuli errors committed, committing any gap acceptance errors also optimally determined pass/fail outcomes in PwMS. Further research may focus on visual, cognitive, and/or motor impairments underlying adjustment-to-stimuli and gap acceptance errors for eventual development of rehabilitation strategies for PwMS.

Development and Validity of Western University's On-Road Assessment.

Although used across North America, many on-road studies do not explicitly document the content and metrics of on-road courses and accompanying assessments. This article discusses the development of the University of Western Ontario's on-road course, and elucidates the validity of its accompanying on-road assessment. We identified main components for developing an on-road course and used measurement theory to establish face, content, and initial construct validity. Five adult volunteer drivers and 30 drivers with multiple sclerosis participated in the study. The road course had face and content validity, representing 100% of roadway components determined through a content validity matrix and index. The known-groups method showed that debilitated drivers (vs. not debilitated), made more driving errors ( W = 463.50, p = .03), and failed the on-road course, indicating preliminary construct validity of the on-road assessment. This research guides and empirically supports a process for developing a road course and its assessment.

Interrater reliability of Western University's on-road assessment.

BACKGROUND: Little empirical support exists for interrater reliability between evaluators from different backgrounds when assessing on-road outcomes of drivers. PURPOSE: We quantified interrater reliability of on-road outcomes between a certified driving school instructor (DI) and an occupational therapist and certified driver rehabilitation specialist (CDRS). METHOD: Both raters used the Global Rating Score (GRS) with two levels (pass, fail), the GRS with four levels (pass, pass with recommendations, fail remediable, fail), and the priority error rating score (PERS; most frequently occurring on-road errors in priority order) to assess 35 drivers (age, M = 48.31 years, SD = 9.76 years; 40% male; 86% with multiple sclerosis). FINDINGS: The DI and occupational therapist CDRS had excellent agreement on the GRS with two levels (κ = .892, p < .0001), GRS with four levels (κ = .952, p < .0001), and the PERS (κ = .847-.902, p < .0001), indicating interrater reliability. IMPLICATIONS: This research contributes to empirical support for the on-road assessment.