Coherence of Hand Muscles During Activities of Daily Living

This paper applies the Coherence Spectrogram (CS) to forearm muscles of 22 patients performing activities of daily living in order to study the spectral characteristics of forearm muscle coherence. This study is novel in that it observes coherence spectra between EMG locations on the arm for three sources of coherent activity, namely that from sensors reading the same muscle, agonistic muscles, and antagonistic muscles. Coherent activity for thumb actuation was observed when comparing EMG from the dorsal and palmar forearm halfway between the elbow and hand above the radius. This was the largest source of coherence in the entire data set. This research could be improved by observing joint angles during actions and increasing the time resolution. The application of CS algorithm to forearm EMG provides a novel tool for analysis of human interface devices, and can be used to observe different physiological actions of muscles during activities of daily living. A complete appendix of muscle origin, insertion, action, and joint angle for the forearm and hand can be shared upon request.