Sonomyography: Monitoring morphological changes of forearm muscles in actions with the feasibility for the control of powered prosthesis

  title={Sonomyography: Monitoring morphological changes of forearm muscles in actions with the feasibility for the control of powered prosthesis},
  author={Zheng, Yong-Ping and Chan, MMF and Shi, Jun and Chen, Xin and Huang, Qing-Hua},
  journal={Medical engineering \& physics},

Electromyography (EMG) has been widely used for the assessment of musculoskeletal functions and the control of electrical prostheses, which make use of the EMG signal generated by the contraction of the residual muscles. In spite of the successful applications of EMG in different fields, it has some inherent limitations, such as the difficulty to differentiate the actions of neighboring muscles and to collect signals from deep muscles using the surface EMG. The majority of current EMG controlled prostheses can only provide sequential on–off controls using signals from two groups of muscles, so the users are required to put many conscious efforts in monitoring the speed and range of motion of the terminal devices being controlled. Recently, many alternative signals based on the detection of dimensional changes of muscles or tendons during actions have been reported. The objective of this study was to investigate the potential of the dimensional change of muscles detected using sonography for musculoskeletal assessment and control. A portable B-mode ultrasound scanner was used to collect the dynamic ultrasound images of the forearm muscles of six normally limbed young adults and three amputee subjects. A motion analysis system was used to collect the movement of the wrist angle during the experiments for the normal subjects. It was demonstrated that the morphological changes of forearm muscles during actions can be successfully detected by ultrasound and linearly correlated (R2 = 0.876 ± 0.042, mean ± S.D.) with the wrist angle. We named these sonographically detected signals about the architectural change of the muscle as sonomyography (SMG) http://levitra..magra/. The mean ratio between the wrist angle and the percentage deformation of the forearm muscle was 7.2 ± 3.7°/% for the normal subjects. The intraclass correlation coefficient (ICC) of this ratio among the three repeated tests was 0.868. The SMG signals from the residual forearms were also successfully detected when the three amputee subjects contracted their residual muscles. The results demonstrated that SMG had potentials for the musculoskeletal control and assessment.

The authors of \cite{zheng2006sonomyography} investigated the potential application of detection in muscle morphological changes using ultrasound images for musculoskeletal assesment and control.
As in other studies ultrasound image sequences are captured and morphological measures of muscles are estimated, in this case using a tracking algorithm to track manually delimited region of interest known as sonomyogrphy.
Ultrasound images of the fore arm of six normall subjects and three amputee subjects were obtained.
Simultaneously a motion capture ssystem was used to collect the wrist angle during movement of normal subjects.
The morphological changes of muscles could be detected and are correlated with wrist angles.
The morphological changes by SMG of amputed subjects were also succesfully detected.
The results of this study shows potential applications of SMG to control musculoskeletal prothesis.
However its aplications, the equipment used in this study to capture ultrasound images is too expensive and impractical so that a less precise but more practical device sohuld be used.