Wearable-based digital biomarker provides a valid alternative to traditional clinical measures for post-stroke upper-limb motor recovery

Existing clinical assessments for upper-limb motor rehabilitation post-stroke pose limitations as endpoints for efficient clinical trials. This study aims to develop the Digital Arm Performance Scale (DAPS), a wearable-based digital biomarker for assessing motor recovery using accelerometer data collected in naturalistic environments. Approximately 23,000 hours of data from 215 participants, including subacute and chronic stroke survivors and healthy individuals, were analyzed. The proposed analytical approach decomposed continuous accelerometer data into lower-level movement segments, from which key features were extracted and aggregated using a linear mixed-effects model to produce an interpretable biomarker. DAPS demonstrated excellent reliability, sensitivity, concurrent validity, known-groups validity, discriminant validity, responsiveness, and enabled nearly 60% reduction in the required sample size for clinical trials compared to traditional assessments. These findings highlight its potential as a low-burden, scalable assessment tool for upper-limb motor recovery, with applications in both clinical trials and practice.

Recommended citation: Wang, R., Lang, C. E., Stoykov, M. E., Bonato, P., & Lee, S. I. (2025). Wearable-based digital biomarker provides a valid alternative to traditional clinical measures for post-stroke upper-limb motor recovery. medRxiv, 2025-01.
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