Abstract
Using an ankle spasticity measurement device, we developed a calculation formula and a measurement method for stiffness which was a quantitative index of muscle-tendon extensibility. Stiffness was calculated using acquired data of an angle sensor and a gyro sensor by the suggested formula, and they were compared to verify the validity. 9 healthy adult subjects were given to continuous electrical stimulation (4 levels intensity) of the plantar flexor muscles of the ankle joint to reproduce pseudo hypertonia. We performed a two-way ANOVA with sensor and stimulus intensity as factors to compare the two groups. As a result, only the stiffness calculated using the data of a gyro sensor increased according to the stimulus intensity increased. The following is suggested as to the cause of this problem. When using an angle sensor, the angular acceleration needs to be calculated by second-order differentiation of the angle data. However, noise is amplified by numerical differentiation, and the accuracy of the stiffness measurement is reduced. Therefore, the ankle spasticity instrumentation device with a gyro sensor has enabled the measurement of ankle stiffness with high validity.
https://ror.org/02z5nms51 
