Evaluation of Lower Limb Motor Function Using Wireless Motion Sensors—A Comparison of Normal Elderly Subjects and those Requiring Support Level 1

This study quantitatively compared lower limb motility of normal subjects and those requiring support level 1 (support_1). We developed a wireless inertia sensor with an embedded tri-axial accelerometer and angular velocity sensor. Six normal elderly subjects and ten elderly subjects who were classified as support_1 by the Japanese care insurance system participated in the study. We attached the wireless motion sensors to the center of the lower back and both thighs in the subjects. Subjects were then asked to walk 10 m and perform a stepping exercise. For the evaluation, the cadence, pitch angle, and pitch angular velocity of the thigh auto-correlation function and root mean square (RMS) on the lower back were calculated. The autocorrelation coefficient function for the support_1 subjects was smaller than in the normal subjects, while the RMS was larger in support_1. These differences indicated that the gait and balance abilities of the support_1 subjects were poorer than those of the normal subjects. This suggests that our wireless motion sensor is useful for assessing the motility of the lower limbs while walking and climbing steps.