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Published on: April 21, 2017
Comparison of Consumer Smartwatch and Research-Grade Accelerometer-Derived Step Counts in Amyotrophic Lateral
Gordon Jewett1,2,3, Reed Ferber4,5, Colin B Josephson2,3,6,7,8,9
1Data Intelligence for Health Lab, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Muscle & Nerve
|June 19, 2026
Summary
Smartwatch monitoring is feasible for long-term remote tracking in amyotrophic lateral sclerosis (ALS). While smartwatch step counts correlate well with accelerometers, they are lower and have wide agreement limits, suitable for group analyses.
Area of Science:
- Neurology
- Biomedical Engineering
- Digital Health
Background:
- Amyotrophic lateral sclerosis (ALS) requires objective, scalable functional measures.
- Research-grade accelerometers are effective but challenging for remote monitoring.
- Consumer smartwatches present a practical alternative for long-term data collection.
Purpose of the Study:
- To assess the feasibility of long-term smartwatch monitoring in ALS patients.
- To compare daily step counts derived from smartwatches and accelerometers.
Main Methods:
- A prospective observational study involving 40 ALS participants.
- Participants wore a smartwatch (Fitbit Sense) and an accelerometer (ActiGraph GT9X Link) concurrently.
- Data analysis included paired comparison of daily step counts on valid wear days.
Main Results:
- Data from 39 participants across 8093 smartwatch and 915 accelerometer days were collected.
- A strong correlation (r=0.91) was found between smartwatch and accelerometer step counts.
- Smartwatches systematically underestimated step counts compared to accelerometers, with wide limits of agreement.
Conclusions:
- Long-term remote monitoring using smartwatches is feasible in ALS.
- Smartwatch data is strongly correlated with accelerometer data but shows device-specific bias.
- Smartwatch-derived step counts are potentially useful for group-level and longitudinal ALS studies.
