In MS, wearable sensors may help identify people at risk of worsening disability

EMBARGOED FOR RELEASE UNTIL 4:00 P.M. ET, WEDNESDAY, MARCH 4, 2026

MINNEAPOLIS — Wearable sensors may help identify people with multiple sclerosis (MS) who are more likely to have worsening disability and loss of brain volume, according to a study published on March 4, 2026, in Neurology®, the medical journal of the American Academy of Neurology. The study found that people with changes in their activity patterns were more likely to have worsening disability and loss of brain volume than people whose patterns did not change as much or at all.

The study does not prove that changes in activity lead to progression of MS; it only shows an association.

Wearable sensors measure how much light, moderate or vigorous physical activity people had during the day, how much time they spent sitting or inactive, and their circadian rhythms, or sleep-wake patterns.

“Timely identification of patients at risk for disease progression is essential to reduce long-term disability, but the current tests for measuring MS disability are not designed to detect small changes,” said study author Kathryn C. Fitzgerald, ScD, ScM, of Johns Hopkins University in Baltimore, Maryland. “Using a relatively inexpensive and accessible device around the wrist may help us identify early changes in the disease.”

The study involved 238 people with MS with an average age of 55 and who had been living with MS for an average of 13 years. At the start of the study, they had an average disability level of 3 on the Expanded Disability Status Scale, a scale that measures disability in MS, which indicates no problems with walking, but moderate disability in one of eight functional systems such as muscle weakness, problems with balance or problems with thinking and memory or mild disability in three or four areas.

People had no other serious health problems that could affect their physical activity and had not had an MS relapse within six months prior to the study.

The participants wore devices around their wrists 24 hours a day to measure their activity levels for two weeks. They did this every three months for an average of three years. They also took tests every six months to check their disability levels. They had brain scans at the start of the study and after two years to look for any changes in the brain.

During the study, 120 people had progression of the disease. People who had decreases in their daytime activity levels were more likely to have disease progression. People who had decreases in their activity levels in the first half of the day were about 20% more likely to have disease progression than people who did not have decreases in their activity level.

People who had declines in their activity levels in the morning, from 8:00 a.m. to 10:00 a.m., were more likely to have loss of volume in their brains. Every standard deviation decline in activity level was associated with a 0.18% decrease in whole brain volume as well as a 0.34% decrease in deep gray matter and a 0.35% loss in the volume of the thalamus area of the brain.

“More research is needed to confirm these findings, but it’s exciting to think that using easily accessible devices could help us predict who is at risk of worsening disease and potentially prevent those changes,” Mowry said. “Detecting small changes could also help us speed up research on new treatments.”

A limitation of the study is that a group of people who did not have MS was not included, which would help researchers understand how activity levels may change as a part of normal aging. Also, the participants were relatively older and more disabled, so the results may not apply to younger people with MS and those with less disability.

The study was supported by the National Institutes of Health.

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The American Academy of Neurology is the leading voice in brain health. As the world’s largest association of neurologists and neuroscience professionals with more than 44,000 members, the AAN provides access to the latest news, science and research affecting neurology for patients, caregivers, physicians and professionals alike. The AAN’s mission is to enhance member career fulfillment and promote brain health for all. A neurologist is a doctor who specializes in the diagnosis, care and treatment of brain, spinal cord and nervous system diseases such as Alzheimer's disease, stroke, concussion, epilepsy, Parkinson's disease, multiple sclerosis, headache and migraine.

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