Mutual Information Analysis of Body Sway Accompanied by Tactile Apparent Movement

Abstract

In this research, we examined a tactile sense for sensory substitution in people who have lost a certain sense. We considered use of apparent movement to communicate something via a tactile sense. It is necessary to measure a tactile apparent movement objectively and quantitatively because of an apparent movement is normally a subjective sense. This paper proposes the technique which measure the body sway accompanied by the recognition of a tactile apparent movement more securely. We examined the sway of body part by using EMGs around a shoulder, 3 axes acceleration data of the forearm, tracking data based on CCD camera of the upper part, and center of gravity sways of a person's body. By assuming a causal relationship between the sway of body part and EMGs, as an input and an output of the information channel, the transition probabilities and the averaged mutual information were obtained for 4 normal subjects. Moreover, relationship between a tactile apparent movement and tactile stimuli was investigated by the multiple comparison test. As a result, relevance with the body sway accompanied by the recognition of a tactile apparent movement and EMGs was evaluated quantitatively.