Comparison of sonomyography and electromyography of forearm muscles in the guided wrist extension

Electromyography (EMG) and ultrasonography have been widely used for skeletal muscle assessment. The muscle thickness change detected using ultrasound has been recently defined as sonomyography. In this study, the performances of one dimensional sonomyography (1-D SMG) and surface EMG signal in tracking the guided patterns of wrist extension were compared, and the potential of 1-D SMG for skeletal muscle assessment and prosthesis control was investigated. Sixteen normal subjects were instructed to perform the wrist extension under the guidance of displayed sinusoidal, square and triangular waveforms at movement rates of 20, 30, 50 cycles per minute. SMG and EMG root mean squares (RMS) were collected from the extensor carpi radialis respectively and their RMS errors in relation to the guiding signals were compared. Paired t-test showed that the RMS errors of SMG tracking were significantly smaller than those of EMG. The results suggest that SMG signal has great potential to be an alternative method of EMG to evaluate muscle function and control prosthesis.