Ten-year disease progression in multiple sclerosis: walking declines more rapidly than arm and hand function

From a clinical perspective there is a difference in the decline of arm and hand function and leg function in patients with multiple sclerosis (PwMS). Therefore, this study investigated the course of walking and arm and hand functions in PwMS over the first 10 years after diagnosis, including whether any function declined earlier or faster.

A long-term prospective follow-up study of an incidence cohort of 156 patients with a definite diagnosis of MS, either non-relapse onset (n=28) or relapse onset (n=128) type. Participants were systematically examined immediately after definite diagnosis, at 6 months, and at 1, 2, 3, 6 and 10 years. Walking was determined with the fast 10-meter timed walk test (10mTWT), arm and hand function with the Action Research Arm test (ARAT) and the nine-hole peg test (9HPT). The 10-year trajectories of walking and arm and hand functions were compared using standardized z-scores.

From 3 years onwards the z-scores of the arm and leg function were visually diverging, with a trend towards significance at 6 years, and at 10 years the 10mTWT z-score is significantly higher than the 9HPT. This difference is more pronounced in non-relapse onset patients than in patients with relapse onset type MS, but present in both groups over the first 10 years. In the non-relapse onset group a difference in z-scores at 10 years post-diagnosis between the 10m TWT and 9HPT was found of -12.94 (95% confidence interval (CI) -20.2 to -5.73) for the right and -10.14 (95% CI -17.3 to -2.93) for the left hand. In the relapse onset group there was a difference at 10 years post-diagnosis of -2.17 (95% CI -3.75 to -0.59) for the right and a difference of -2.29 (95% CI -3.87 to -0.71) for the left hand.

This is the first longitudinal study that shows that walking declines earlier and more rapidly than arm and hand function in patients with MS. These results give important insights that can be linked to the pathophysiological disease process regarding the ascending order of deterioration in patients with MS.