Journal of Rehabil itation Research & Development Dynamic monitoring of forearm muscles using one-dimensional sonomyography system

Abstract—We introduce a method, known as one-dimensional sonomyography (1-D SMG), that uses A-mode ultrasound sig-nals to detect dynamic thickness changes in skeletal muscle during contraction. We custom-designed a 1-D SMG system to collect synchronized A-mode ultrasound, joint angle, and sur-face electromyography (EMG) signals of forearm muscles dur-ing wrist extension. We extracted the 1-D SMG signal from the ultrasound signal by automatically tracking the corresponding echoes, which we then used to calculate muscle thickness changes. We tested the right forearm muscles of nine nondis-abled young subjects while they performed wrist extensions at 15.0, 22.5, and 30.0 cycles/min and their largest wrist exten-sion angle ranged from 80 ° to 90°. We found that the muscle deformation and EMG root mean square signals correlated lin-early with wrist extension angle. The ratio of deformation t