A Motor Point Tracking Stimulation Device for surface FES on Biceps Brachii

Functional electrical stimulation (FES) is one of the early rehabilitation methods to restore motor function in patients suffered from central nervous system disorder. To improve the stimulation efficiency of FES, studies have been conducted on methods to stimulate the motor point (MP). Since the position of the MP on the skin changes with changes in muscle geometry during dynamic rehabilitation, this study proposes a MP tracking stimulation (MPTS) device to reduce muscle fatigue by accurately stimulating the MP by controlling electrode positions using a linear actuator. To deliver stimulation to the biceps brachii, the device follows and stimulates the MP by moving the stimulating electrode in accordance with the elbow joint angle measured by a rotary encoder. As an evaluation of this device, we compared the MPTS device with a conventional method of simultaneous 3-channel stimulation (SS). A muscle fatigue protocol was used to compare the effect of the two methods on muscle fatigue. The results showed that the rate of change in maximum voluntary contraction force (MVC) before and after the experiment was significantly smaller using MPTS than SS. MPTS has been indicated to be an effective method for reducing muscle fatigue associated with FES.