Extension of the Interface for Visual Feedback of Center of Foot Pressure in Insole Type Measurement Device

Abstract

Ankle osteoarthritis (AOA) is a disease with a high prevalence in the elderly. Sensory feedback is considered to be an effective tool in the rehabilitation of patients and is commonly used. In the previous study, the relationship between plantar pressure and static balance during walking in elderly people was suggested, and it is thought to be applicable to AOA patients. In this study, we developed a system to present the data to subjects in real time. For this purpose, we used an insole-type plantar pressure measurement device and a bracelet-type display device to measure the gait of a healthy person when walking naturally and when wearing the display device on the right arm and the left arm. In this experiment, Bluetooth was used for communication between the measurement device and the display device. Since it was necessary to reduce the sampling frequency to use wireless communication, we created 10 Hz ~ 60 Hz data from 200 Hz data and compared them. The results showed that the x-axis of plantar pressure showed no change compared to the 200 Hz data when the sampling frequency was over 30 Hz. On the other hand, for the y-axis, even at 60 Hz, we could not obtain a waveform that matched the 200 Hz data. The data of 40 Hz or higher can be used as a reference for feedback rather than analysis. In the comparison between natural walking and walking with the display device, the x-axis displacement increased when walking with the display device. The displacement of subjects considered to be right-footed was larger for the right foot, and two different results were obtained for neither the right nor the left foot. From the above, we were able to find the characteristics of plantar pressure in each gait. In addition, we were able to find the necessary sampling frequency for using wireless communication.