A Reliable Muscle Synergy Extraction Method based on Multivariate Curve Resolution-Alternating Least Squares

Yehao Ma,Sijia Ye,Changcheng Shi,Guokun Zuo,Dazheng Zhao,T Zhu,A Sharifi,M Anpo

doi:10.1051/e3sconf/202127103019

Abstract

Muscle synergy is an important approach to evaluate motor function for patients with neurological diseases. Nonnegative matrix factorization (NMF) is the most widely used muscle synergy extraction method from electromyography (EMG) data. However, NMF usually falls into local optimum and is susceptible to noise, which significantly limit the promotion of muscle synergy. In this paper, a reliable synergy extraction method based on multivariate curve resolution-alternating least squares (MCRALS) was put forward. Its performance was compared with NMF through analyzing the EMG data of upper limb motor. The repeatability and intra-subject consistency were used to evaluate the two methods. As a result, MCR-ALS provided unique resolution result and better repeatability and consistency in contrast to NMF. Thus, the results of this study are of significance for the expansion and application of muscle synergy in medicine.

Highlights

Muscle synergy was proposed to answer how the central nervous system (CNS) to accomplish complex motor
Muscle synergy provides an important approach to quantify the covariation of the muscle during a task, and its is used to evaluate the motor function of the patients with stroke[4], spinal cord injury[5] and cerebral palsy[6]
Muscle synergies were extracted with average variance account for (VAF) values of 87.82±4.80% and 88.05±4.65% for Nonnegative matrix factorization (NMF) and multivariate curve resolutionalternating least squares (MCR-alternating least squares (ALS)), respectively

Summary

Introduction

Muscle synergy was proposed to answer how the central nervous system (CNS) to accomplish complex motor. CNS coordinately activate these synergies to overcome the complexity of limb dynamics for musculoskeletal system[1,2]. Despite the physiological origin and meaning of muscle synergies are still debated [3], it is certain that motor task execution can be described by the coordination of a limited number of muscle synergies. A muscle synergy is the activation of a group of muscles contributing to a particular movement, reducing the dimensionality of muscle control. Muscle synergy provides an important approach to quantify the covariation of the muscle during a task, and its is used to evaluate the motor function of the patients with stroke[4], spinal cord injury[5] and cerebral palsy[6]

Methods

Results

Conclusion