EMG analysis and evaluation of body-sway evoked by tactile stimuli

Tactile sense as one of the five regular senses of human body has always been considered as an efficient substitution for the other senses of body such as sight and hearing. For example, a tactile interface system is able to transfer an essential set of information by using the tactile sense instead of visual or hearing sense. Today we can see the various applications of this substitution in different interface and interactive display systems that are helping people specially the physically challenged ones to perform many of their daily tasks despite of a loss in one of their sensory organs [1]. The concept of tactile apparent movement recognition that have boon considered in this research is normally a subjective sense of human body. The term apparent movement refers to the illusory perception of a movement on skin that is created by the discrete stimulations of a number of points on skin of a part of body that are appropriately separated in space and time and can be controlled by different parameters. These parameters have been studied particularly in this research. Applying the tactile apparent movement to an individually defined engineering system, a quantitative evaluation study becomes necessary and possible. In previous studies, finding the body-sway (testing arm of an experiment subject) caused by the tactile apparent movement in a fixed experimental condition became possible. However, characteristic of the body-sway that appeared in the experiment was not thoroughly investigated. In this study, investigating the body-sway caused by tactile apparent movement in a fixed experimental condition was aimed. Therefore, we focused on 3 group of information; the biological information, the body-sway and the information that resulted from the comparison between the apparent movement recognized trials and the non-recognized trials. The EMG data recorded under particular tactile stimuli was analyzed by performing the time-to-frequency transform tools as the short-time Fourier transform (STFT). The findings of this research will be conducive to optimize the performance of the systems that are using the tactile apparent movement.