Shain, Adam Hersh. Characterization of the flexor digitorum superficialis as a predictor of grasping strength. Retrieved from https://doi.org/doi:10.7282/T3RJ4JQ0
DescriptionThe activity of forearm musculature during grasp has been studied by a variety of testing modalities in order to assess muscular conditions, predict grasping strength and control powered prosthetics. Myotonometry has been shown to correlate directly to changes muscle stiffness and tone for the assessment of muscle recovery but has no real time application and is limited to rehabilitative and physical therapy application. Of all testing modes Force Myography (FMG) is the only one that has demonstrated simultaneous multifunctional and multi degree of freedom control of prosthetic hands with sensors placed over the surface of the skin. These studies, however, were not able to identify magnitudes of individual muscle activation for control of volitional movement. In the present study a new testing modality is introduced, targeted Force Myography (tFMG). tFMG detects the change in radial pressure and stiffness of a single muscle during contraction through the voltage response of a single force sensing resistor (FSR) strapped above the muscle body intrinsically combined with the overall change in radial pressure of the harnessed body segment. In this study tFMG of the flexor digitorum superficialis is assessed during power grasp. The results correlate well to myotonometry, r2 = 0.86, and show the ability to predict a subject's level of muscle activation, r2 = 0.94 +/- .03. This was achieved through the development of inexpensive testing fixtures and methods in order to linearize and calibrate the voltage response curves of FSRs, making them an accurate and reliable tool in the assessment of grip force and forearm pressure. It is demonstrated here that tFMG results have the ability record the changing stiffness of the underlying muscle as well as predict grasping strength.