In MS, Leg Function Declines More Rapidly Than Hand Function, Study Finds

A new analysis of disease progression in patients with multiple sclerosis (MS) suggests patients’ ability to walk declines more rapidly than their hand function.

The study, published in the journal Multiple Sclerosis and Related Disorders, lends new context into how the disease typically affects patients as time goes on.

Investigators from Amsterdam University Medical Centers, in the Netherlands, noted that the exact mechanism of MS disease progression remains a topic of discussion.

“Initially, impairments caused by MS progression were seen as a direct consequence of white matter lesions in the brain and spinal cord,” said S.T. Timmermans, the study’s corresponding author, in an email to The American Journal of Managed Care®. “The (possible) impact of neurodegeneration on MS disease progression, related to impairment of different parts of the body, is getting more attention the last couple of years.”

Timmermans and colleagues noted that in patients with non-relapse onset (NRO) MS, the neurodegenerative process begins earlier than in patients with relapse-onset (RO) MS. Atrophy of white and gray matter, however, appears at an early stage in all MS patients, regardless of type.

The authors decided to evaluate differences between the progression of different types of impairment and see if any trends emerged, as well as whether there was a difference in such trends among patients with NRO and RO MS.

The authors constructed a long-term (10-year) prospective follow-up study of 156 patients with MS. Of the total, 28 had NRO MS, the rest had RO MS.

Patients were examined at diagnosis, at 6 months, and then five more times through the first decade. To gauge a patient’s walking impairment, the authors used the 10-meter timed walk test (10mTWT). Arm and hand function were evaluated using the Action Research Arm test (ARA) and the 9-hole peg test (9HPT). The authors then used standardized z-scores to analysis the trend of walking and hand function.

What they found was that by the third year following diagnosis, the trajectories of leg and arm function began to diverge.

“Three years post-diagnosis we started seeing a divergence in the NRO group, at 6 years there was a clear trend, and at 10 years this difference between leg function and arm and hand function was significant in both RO and NRO type MS,” the authors wrote.

Just what is causing the disparity is difficult to know for sure, but the investigators said it could be a sign that neurodegeneration is occurring sooner than previously thought.

“We assume that one of the explanations might be that the longest corticospinal tracts are impacted first in the disease process of patients with MS causing the earlier and faster deterioration of leg function,” they said. “The corticospinal tracts are the connection between the brain motor cortex and the lower and upper extremities.”

Timmermans said such questions warrant further research.

In the meantime, he said these findings offer clinicians the opportunity to provide patients with more precise expectations.

“The results of this study can help paint a clearer picture, both for physicians and newly diagnosed patients with MS, about the expected impact of impairments of arms and legs on daily functioning,” he said. “But in our view physicians should always focus on the specific health complaints of the patient in front of them.”

Reference

Timmermans S, Groot VD, Beckerman H. Ten-year disease progression in multiple sclerosis: walking declines more rapidly than arm and hand function. Mult Scler Relat Disord. Published online June 26, 2020. doi:10.1016/j.msard.2020.102343