A biosignal analysis for reducing prosthetic control durations: a proposed method using electromyographic and mechanomyographic control theory

OBJECTIVES: This project proposes a unique methodology utilizing electromyography and mechanomyography to determine the intensity of a desired movement which may be useful in further developing decomposition algorithms for prosthetic controls. METHODS: Ten males performed isometric leg extension muscle actions corresponding to 20, 40, 60, 80, and 100% of their maximal voluntary isometric contraction force. The duration and amplitude of the gross lateral movement of the mechanomyographic signal as well as electromechanical delay were measured during each contraction. RESULTS: The results indicated that the duration of the gross lateral movement decreased with increases in intensity (20<40=60<80<100% maximal voluntary isometric contraction) and that the amplitude of the gross lateral movement increased with increases in intensity (20<40=60<80<100% maximal voluntary isometric contraction). In addition, electromechanical delay decreased with each increase in intensity. These measurements occurred within 40 ms from the onset of the electromyographic signal. CONCLUSIONS: Thus, these measurements may be incorporated into existing prosthetic control algorithms to reduce grasp times and identify the intensity of a movement earlier. In addition, the gross lateral movement and electromechanical delay measurements may provide more intuitive controls for prosthetic users.