Postural stability evaluation using wearable wireless sensor

This paper presents a wearable wireless sensor as a support tool used to assess the postural stability of a subject. Changes in postural steadiness are age-related. Their characterization and identification, through the development of a non-invasive device, will allow to identify persons at risk. In this work we develop an accurate device for real-time estimation of balance parameters with the aim to reduce falls in the elderly population. The proposed device embeds a 3-axis accelerometer, a 3-axis gyroscope and a 3-axis magnetometer. In order to get an accurate estimation of the displacement of the Center of Gravity (CoG) and of the Centre of Pressure (CoP), a data fusion algorithm is used. In particular, an Attitude and Heading Reference System (AHRS) has been implemented and optimized to provide an estimate of the orientation of the human body wearing the sensors. Moreover, we proposed an algorithm to evaluate the postural stability. Therefore, our algorithm has the aim of obtaining the CoG and CoP displacements in the anterior-posterior (AP) and medial-lateral (ML) directions, from the information provided by the AHRS, based on the inverse pendulum mathematical model. Results from these experiments on a population of healthy subjects suggest that the proposed device and algorithm can effectively be used for measuring CoG and CoP displacements.