Real-time isometric finger extension force estimation based on motor unit discharge information
Objective . The goal of this study was to perform real-time estimation of isometric finger extension
force using the discharge information of motor units (MUs). Approach . A real-time electromyogram
(EMG) decomposition method based on the fast independent component analysis (FastICA) algorithm was
developed to extract MU discharge events from high-density (HD) EMG recordings. The decomposition
was first performed offline during an initialization period, and the obtained separation matrix was
then applied to new data samples in real-time. Since MU pool discharge probability reflects the
neural drive to spinal motoneurons, individual finger forces were estimated based on a firing
rate-force model established during the initialization, termed the neural-drive method. The
conventional EMG amplitude-based method was used to estimate the forces as a comparison, termed the
EMG-amplitude method. Simulated HD-EMG signals were first used to evaluate the accuracy of the
real-t...