Investigating the relationship between multiple sclerosis disability and driving performance: A comparative study of the multiple sclerosis functional composite and expanded disability status scale.

ABSTRACT

INTRODUCTION: Multiple Sclerosis (MS) can affect the ability to perform complex tasks such as driving. The Expanded Disability Status Scale (EDSS) overlooks cognitive deficits crucial for driving. We investigated the relationship between the Multiple Sclerosis Functional Composite (MSFC), which includes cognitive assessment, and EDSS in relation to driving performance. METHODS:  This exploratory study involved 30 MS patients (mean EDSS 2.4 ± 2.0) and 15 healthy controls. We correlated the results of the EDSS, MSFC, and driving performance tests, namely the Two-Hand Coordination Test (2HAND) and the Speed Anticipation Reaction Test (SART). RESULTS: Patients did not differ from the healthy controls regarding age, sex, and driving experience. However, they exhibited lower mean Z-scores in MSFC, particularly in motor domains, but not in cognitive function. The mean Z-score for the 25-foot Walk test was -0.42 in patients compared to -0.04 in controls. For the 9-hole Peg Test, it was 0.17 in patients versus 1.47 in controls. Patients had a mean total error time of 19.7 seconds for both hands in the 2HAND test, compared to 7.7 seconds in controls. In MS patients, the MSFC and EDSS significantly correlated with SART and 2HAND components. While upper limb function (9-HPT) did not correlate with 2HAND, cognitive function (PASAT) did correlate with the number of 2HAND errors, indicating that cognitive dysfunction impacts driving performance more than physical dysfunction. CONCLUSION: The MSFC may provide valuable insights into the driving abilities of MS patients, potentially offering advantages over the EDSS in predicting driving performance. Further research with larger, more diverse populations across various driving environments is necessary to validate these findings.