Association of Changes in Activity Patterns With Brain Atrophy and Disability Progression in People With Multiple...

Area of Science:

• Neurology
• Biomedical Engineering
• Rehabilitation Science

Background:

• Multiple Sclerosis (MS) is a chronic neurological disease characterized by progressive disability.
• Subtle changes in daily activity may indicate early disease progression in people with MS (PwMS).
• Objective monitoring of physical activity is crucial for understanding disease trajectory.

Purpose of the Study:

• To determine if accelerometry can detect subtle, longitudinal changes in disability among PwMS.
• To assess the relationship between accelerometry-derived activity measures and brain atrophy and disability worsening at an individual level.

Main Methods:

• Longitudinal study of 238 PwMS (aged ≥40) over 3 years, with annual brain MRI and quarterly accelerometer use.
• Accelerometry measured total activity, sedentary time, and circadian rhythm parameters.
• Disability worsening assessed via Expanded Disability Status Scale-plus (EDSS+); brain atrophy via whole-brain segmentation.

Main Results:

• A 2.0% annual decline in total activity was observed.
• Within-person decreases in daytime activity (8:00-14:00) significantly predicted higher risk of EDSS+-confirmed disability progression.
• Declines in morning activity correlated with increased whole-brain, deep gray matter, and thalamic volume loss.

Conclusions:

• Reductions in daytime activity patterns precede clinical disability worsening and brain atrophy in PwMS.
• Longitudinal accelerometry shows promise as a sensitive, noninvasive biomarker for detecting subclinical disease progression in MS.
• Further research is needed to establish thresholds and responsiveness for accelerometry measures.