TOPLINE

Among patients with primary progressive multiple sclerosis (MS), real-life walking speed (RWS) measured with wearable accelerometers identified disability progression earlier and more frequently than conventional clinical tests.

METHODOLOGY

• Researchers conducted a prospective cohort study to determine whether tracking RWS via wearable accelerometers can detect disability progression earlier than conventional clinical tests in patients with primary progressive MS.
• The study analysed 110 patients with primary progressive MS (mean age, 51 years; 34.5% women; median Expanded Disability Status Scale [EDSS] score, 3.5) at a university medical centre in Germany between 2012 and 2022. Patients were followed up for a median duration of 5 years, with visits occurring every 3 months in the first year and then annually.
• At each visit, participants wore a wearable accelerometer for 1 week under usual living conditions, with valid measurements averaging 16.1 h/d of wear time.
• Outcome measures included the EDSS and standard Multiple Sclerosis Functional Composite metrics, such as the timed 25-foot walk (T25FW) test, Nine-Hole Peg Test (9HPT), and Symbol Digit Modalities Test (SDMT), alongside RWS, quantified as the 50th and 90th percentiles of all walking speed samples averaged over 7 consecutive days.
• Disease progression was defined as at least a 20% increase in the T25FW test or 9HPT score, at least an 8-point decrease in the SDMT score, at least a 1.0-point or 0.5-point increase in the EDSS score, or a decrease of at least 0.08 m/sec in RWS.

TAKEAWAY

• RWS declined steadily as disability worsened and showed a broader range of walking performance than the T25FW test, which was clustered within a narrow performance range at baseline, with 62% of patients completing the test in 3-6 seconds.
• Annual rates of disability progression exceeded 30% using RWS, compared with fewer than 20% for the EDSS and SDMT and fewer than 10% for the T25FW test and 9HPT.
• Composite endpoints incorporating RWS at the 50th percentile identified disability progression earlier and more frequently than both T25FW test-based endpoints and the Multiple Sclerosis Functional Composite, with 78% and 86% higher risks for progression, respectively (P < .001 for both).
• Below the EDSS score of 4.5, RWS demonstrated the highest sensitivity to disease progression, and RWS at the 90th percentile remained informative up to the EDSS score of 6; above the EDSS score of 6.5, manual and cognitive assessments were more discriminative.

IN PRACTICE

"RWS measured through precise accelerometry represents a promising, sensitive biomarker of disease progression in PPMS [primary progressive MS]. Its direct impact on daily living and autonomy, together with advances in wearable technologies, offers added value for individualized and research-level monitoring in PPMS and other disease types in an era of practically no relapse and efficient control of MRI activity," the authors wrote.

"These findings highlight the potential utility of incorporating RWS in composite disability endpoints to improve the detection of progression in PPMS," they added.

SOURCE

This study was led by Maeva Cotinat, Hôpitaux Sud, APHM, Aix Marseille University, Marseille, France. It was published online on August 17, 2026, in Multiple Sclerosis Journal.

LIMITATIONS

Differences in the duration of follow-up and shorter observation periods for many patients may have affected the precision of progression estimates. The single-centre design limited the generalisability of the findings. Contextual factors such as lifestyle factors, environmental conditions, or comorbidities potentially affecting RWS were not systematically controlled.

DISCLOSURES

The study was performed by a laboratory member of the France Life Imaging network, with initial data collection and study initiation partially supported by grants from Merck Serono and Novartis. One author declared receiving financial support from the France Life Imaging network, and another author declared serving as the head of Trium Analysis Online GmbH and the Sylvia Lawry Centre for Multiple Sclerosis Research organisations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.