New stimulation method for stimulus point

The purpose of this study was to develop a new type of the sensory feedback system for myoelectrically controlled the biomimetic prosthetic hand. One of the characteristic features of the neuromuscular control system in man is the increase in the compliance around the joint with decreasing activity of the muscle. For the sensory feedback system we used the interferential current that uses two waves and we synthesized low frequency current in the body. We examined whether the difference of stimulus can be detected by the interference current in our previous study. These results showed that the subjects can distinguish the change of stimulus frequency when one frequency was fixed and the other frequency was changed. We confirmed that the interference current was useful method for the sensory feedback system of a prosthetic hand. However, this method can transfer only single information. We want to transfer two kinds of information such as grasping force and finger angle. Therefore, we examined whether the point of the stimulus could be moved with fixed electrodes. Our experimental results showed that the phase change is possible to move the stimulus point. As a future work, we will try to produce a sensory feedback device for a prosthetic hand, using the interference current.