Biomechanical Modeling, Muscle Synergy-Based Rehabilitation Assessment, and Real-Time Fatigue Monitoring for Piano-Integrated Upper Limb Therapy

TL;DR

This paper introduces a new piano-based therapy system that uses biomechanical modeling and real-time fatigue monitoring to improve upper limb rehabilitation.

Contribution

A novel integration of biomechanical modeling, muscle synergy analysis, and real-time fatigue monitoring for piano-based rehabilitation is proposed.

Findings

The biomechanical model accurately predicted interaction forces during piano-playing tasks.

Patients showed improved muscle synergy and similarity to healthy subjects after three weeks of therapy.

The CMFI correlated strongly with subjective fatigue ratings (r > 0.83, p < 0.001).

Abstract

Piano-based occupational therapy has emerged as an engaging and effective rehabilitation strategy for improving upper limb motor functions. However, a lack of comprehensive biomechanical modeling, objective rehabilitation assessment, and real-time fatigue monitoring has limited its clinical optimization. This study developed a comprehensive “key–finger–exoskeleton” biomechanical model based on Hill-type muscle dynamics and rigid-body kinematics. A three-dimensional muscle synergy analysis method using non-negative tensor factorization (NTF) was proposed to quantitatively assess rehabilitation effectiveness. Furthermore, a real-time Comprehensive Muscle Fatigue Index (CMFI) based on multi-muscle coordination was designed for fatigue monitoring during therapy. Experimental validations demonstrated that the biomechanical model accurately predicted interaction forces during piano-playing tasks. After three weeks of therapy, patients exhibited increased synergy modes and significantly improved similarities with healthy subjects across spatial, temporal, and frequency domains, particularly in the temporal domain. The CMFI showed strong correlation (r > 0.83, p < 0.001) with subjective fatigue ratings, confirming its effectiveness in real-time fatigue assessment and training adjustment. The integration of biomechanical modeling, synergy-based rehabilitation evaluation, and real-time fatigue monitoring offers an objective, quantitative framework for optimizing piano-based rehabilitation. These findings provide important foundations for developing intelligent, adaptive rehabilitation systems.

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