The relationship between multiple sclerosis symptom severity measures and performance on driving variability metrics in a virtual reality simulator

Abstract

Objective: Driving ability can be compromised in individuals with multiple sclerosis (MS); however, the progressive nature of multiple sclerosis makes it difficult for clinicians to assess when performance on functional tasks, such as driving, has started to decline. The aim of the study was to evaluate the relationship between two measures of multiple sclerosis severity, the Expanded Disability Status Scale and the Multiple Sclerosis Functional Composite, and minor driving errors in a virtual reality driving simulator. Design: Symptom severity was measured in 31 active drivers with multiple sclerosis using the Expanded Disability Status Scale and Multiple Sclerosis Functional Composite. Driving performance was measured using a standardized virtual reality driving simulator route. Executive functioning, a cognitive function commonly related to driving, was evaluated using the Trail Making Test B. Results: Greater impairment on the Multiple Sclerosis Functional Composite was related to increased difficulty maintaining lane positioning (r = −0.49, P = 0.01) and poorer executive functioning (r = −0.52, P < 0.01). In contrast, the Expanded Disability Status Scale was not related to either measure. Conclusions: These findings suggest that poorer performance on the Multiple Sclerosis Functional Composite, and not the Expanded Disability Status Scale, may indicate vulnerability to minor driving errors as an early sign of driving compromise. The use of screening tools, such as the Multiple Sclerosis Functional Composite, could help clinicians identify increased driving risk and consider comprehensive driving evaluations earlier, before a major driving violation or accident occurs.