Development of a posture monitoring system

Poor postures of the spine have been considered in association with a number of spinal musculoskeletal disorders, including structural deformity of the spine and back pain. Improper posturing for the patients with spinal disorders may further deteriorate their pain and deformities. Therefore, posture training has been proposed and its rationale is to use the patient's own back muscles to keep the spine within the natural curvature. A posture training device may help to facilitate this therapeutic approach by providing continuous posture monitoring and feedback signals to the patient when "poor" posture is detected. In addition, the users of the device may learn good postural habits that could carry over into their whole life.;In this thesis, a portable posture monitoring system has been developed, which consists of 3 inertial sensor modules, a data logging and feedback system, an integrated garment, and with additional software for analysis of posture information and visual display software for providing posture training. The sensor modules were used for tracking the trunk posture change at the thoracic and lumbar regions in the sagittal and coronal planes relative to a neutral position, in terms of curvature alteration measured between adjacent sensor modules. An auto-reset algorithm has been developed and integrated into the measurement system for minimizing the measurement errors due to the inherent limitations of the inertial sensors. In the evaluation process, the measured posture change was compared with the total change of the inter-segmental angles of the trunk measured by a motion analysis system. The results showed that inertial sensor modules could provide trunk posture information of the thoracic and lumbar regions and its measurements were found to be comparable to those of the motion analysis system. The new developed system has been used to monitor posture changes of healthy human subjects and patients with adolescent idiopathic scoliosis during daily activity. The results demonstrated that the subjects could alter their postures with an audio-biofeedback signal provided. This verified the potential of the developed system in facilitating posture training. With this promising result, it is worthy for further developments and enhancements. The ultimate goal of this system is towards applications in occupational health promotion as a prophylactic measure for those jobs with a high-risk of low back pain as well as a treatment option for the patients with posture deviations or spinal diseases.