Real-time wireless ambulatory gait monitoring system incorporating online periodical gait evaluations
thesisposted on 31.01.2017, 04:49 authored by Gouwanda, Darwin
Human gait analysis studies the coordination of human lower extremity in providing propulsion to move forward while maintaining the body balance, with one foot in contact with the ground at all time. Hence, gait analysis plays an important role in clinical settings and rehabilitations. It is widely performed to identify various gait disorders, to assess the functional performance of a patient’s lower limb before and after a surgery or medical treatment, and to evaluate patient’s rehabilitation progress. In engineering, its importance is reflected in the design and development of the prosthetic limb, Functional Electrical Stimulation (FES) system as well as the humanoid robot. Optical motion capture system and force platform are commonly used in gait analysis to quantify human motion. However, these systems are expensive, bulky and can only capture human motion in a dedicated environment i.e. laboratory. As an alternative, this thesis developed a real-time gait monitoring system that utilizes wireless miniature gyroscopes. The miniature gyroscope is small, light-weight, and can capture human motion in both indoor and outdoor environments. More importantly, it is equipped with wireless data transmission, which offers additional benefits. Wireless gyroscope provides relatively larger movement area. It also does not obstruct the natural motion of human lower extremity. Apart from the advantages offered by the wireless gyroscopes, this system also uses several novel methods to assist clinicians and researchers in identifying abnormal gait. These methods evaluate three main aspects of human gait. They are referred as the gait normality test, gait asymmetry analysis, and the estimation of gait dynamic stability. Gait normality test examines a person’s gait relative to normal/healthy individual’s gait that was established by other researchers. Gait asymmetry analysis is an evaluation that examines the bilateral differences between the left and right limbs.The estimation of gait dynamic stability determines human walking stability using nonlinear time series analysis. It uses short-term and long-term maximum Lyapunov exponent to quantify the ability of human neuromuscular locomotor system in maintaining body balance during walking. Experimental study was also conducted to examine the overall capability of this system. This study simulated the abnormal gait by placing a load on one side of the limbs and by wearing a sandal on one foot. These methods successfully altered the inertial property of a person’s lower limb, hence inducing significant differences in spatio-temporal gait parameters between the affected limb and the non-affected limb. As expected, the experimental results were satisfactory. Significant differences between normal and abnormal gait were observed with p < 0.01. These results validated the use of these methods to simulate abnormal gait on a healthy individual. They also demonstrated the viability of this system for future clinical applications.