Risk evaluation of need for care by motion analysis from sitting-up to walking using inertial sensor

Abstract

In order to prevent the need for nursing care in elderly, it is necessary to early detect the decrease of activity. In this study, we propose a new evaluation method for the risk for reduced activity by analyzing posture change from sitting-up to walking. Five sensor units which have three axes accelerometer and gyro-sensor, are attached to the subject's head, trunk, sacrum, thigh, and calf, respectively, to obtain sagittal, frontal, and twist angle changes through the appropriate digital filter. From the results of simulated data by a physical therapist, the characteristics of angle changes in each body part to complete the posture changes, could be observed at the same phase in active subject's data, whereas their characteristics could be observed sequentially in activity-decreased elderly. It is demonstrated that the present method can be useful for the early diagnosis of risk requiring the nursing care.