Daily step patterns may help track disability in progressive MS
Study: They can potentially inform timing of mobility-focused interventions
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Two people walk on a boardwalk. Walking problems are common in MS. (Photo by iStock)
- Tracking daily step patterns offers a more complete picture of disability in progressive MS than occasional clinic visits.
- Patients with greater disability or walking impairment consistently take fewer daily steps.
- Continuous step-count profiles can serve as real-time markers to complement clinical scales and assess functional performance.
Daily step patterns — captured via wearable devices such as smartwatches — may offer a more complete picture of disability in people with progressive forms of multiple sclerosis (MS) than measurements taken during occasional clinic visits, a study found.
Using more than two years of step count data from more than 500 people, researchers found that those with greater MS-related disability or walking impairment generally took fewer daily steps, with the differences especially pronounced during late morning and afternoon. Daily step patterns were also closely associated with clinic-based measures of MS-related disability.
“This study suggests that … step count profiles could be reliable, time-sensitive markers of disability in progressive MS by providing daily, real-time information about when mobility differences are most apparent,” researchers wrote, highlighting “their potential to complement clinical scales and to inform the timing of mobility-focused interventions.”
The study, “Diurnal step count patterns in progressive multiple sclerosis,” was published in the Multiple Sclerosis Journal.
Wearable activity trackers can continuously measure movement
In MS, inflammation and damage to nerve cells lead to movement problems, fatigue, and other symptoms that can make everyday physical activity increasingly difficult. In people with progressive forms of MS, disability gradually accumulates over time.
MS-related disability is tracked using clinic-based measures such as the Expanded Disability Status Scale (EDSS), which assesses walking, balance, and other MS-related functional domains, and the Timed 25-Foot Walk (T25FW), which assesses walking speed and mobility by measuring how long it takes a person to walk 25 feet.
But these tests capture a patient’s performance at a particular moment. They may miss changes in mobility that occur throughout the day outside of scheduled clinic visits. Fluctuations in physical abilities can occur due to factors like fatigue, heat sensitivity, mood, and the body’s natural rhythms.
Wearable activity trackers offer a way to continuously measure movement during everyday life. In healthy adults, physical activity generally increases after waking, peaks around midday, and declines toward evening. Previous research suggests that this daily pattern is altered in MS, particularly as disability increases.
A team of researchers at the University of California, San Francisco therefore set out to examine whether daily step patterns could provide additional information about disability in progressive MS.
Researchers analyzed participants’ step counts minute by minute
The team analyzed step count data from 529 adults, ages 18 to 65, with primary or secondary progressive MS who took part in the Phase 3 SPI2 trial (NCT02936037).
That trial had tested whether a formulation of high-dose biotin could ease disability (EDSS scores) or improve walking speed (T25FW) relative to a placebo in people with progressive MS, but ultimately failed to meet its main goal.
During the 27-month study, participants wore a wrist-worn Fitbit that continuously tracked their steps, while EDSS, T25FW, and other neurological assessments were performed every three months.
For this analysis, researchers analyzed participants’ step counts minute by minute and accounted for periods when the device was likely not being worn, allowing them to map how a person’s activity changed over the course of a typical day.
Higher EDSS scores, reflecting greater disability, and longer T25FW times, reflecting slower walking speed, were consistently associated with lower step counts, particularly in the late morning and afternoon.
Because MS-related symptoms … fluctuate throughout the day … step-count profiles can serve as a proxy that more comprehensively reflects the combined impact of these factors on functional performance.
Compared with people who had EDSS scores of 3 to 3.5 — indicating a degree of disability that doesn’t require walking aids — midday step counts were about 50% lower among those with an EDSS of 6 and 70% lower among those with an EDSS of 6.5. Scores of 6 or 6.5 indicate a more severe level of disability in which a person requires at least one walking aid, such as a cane or crutches.
Similarly, people who needed at least eight seconds to complete the T25FW took about 50% fewer midday steps than those who completed it in less than six seconds.
EDSS was more strongly associated with daily step patterns than the T25FW, although combining the two provided the most information for predicting variations in step count patterns across the day. The researchers suggested this may be because EDSS captures several aspects of neurological function, whereas the T25FW focuses specifically on walking speed.
Looking at the different neurological functions assessed through the EDSS, walking ability, motor function, and coordination explained the most variation in daily step patterns, with walking ability having the strongest association.
“Because MS-related symptoms … fluctuate throughout the day … step-count profiles can serve as a proxy that more comprehensively reflects the combined impact of these factors on functional performance,” the researchers wrote. “Therefore, daily step counts could become a clinically meaningful assessment of physical activity … and complement patient-reported outcome assessments as well as clinic-based assessments for observational studies.”
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