MEMS Biomedical Sensor for Gait Analysis

Abstract

Gait analysis is the study of lower limb movement patterns and involves the identification of gait events and the measurements of kinetics and kinematics parameters. These include for example, toe-off, landing, stance, swing, displacement, speed, acceleration, force, pressure and the pressure-time-integral. Gait analysis is a very important procedure in assessing and improving many quality of life indicators. In sports, gait analysis can be used to improve athlete’s performance and injury prevention. For patients, such as those suffering from diabetes, gait analysis can be used to screen for development of foot ulceration thus preventing them. In term of gait stability, gait analysis is proven to be very helpful in assessing and improving balance among the elderly, patients with diabetes or peripheral neuropathy and many other sicknesses. Gait analysis is also widely used in rehabilitation. The occurrence of fall is becoming more of a significant health threat recently. This is due to the fact that the worldwide phenomenon of growing population of the elderly is continuously observed in many developed and developing countries. It is estimated that the world’s elderly citizen will reach 2 billion in 2050 from current figure of 670 million. To make matters worse, the total number of the world’s diabetic sufferers is increasing from 171 million in 2000 to 366 million in 2030, with an obvious trend of surging proportion for the above 65 years group. In order to further understand the situation that leads to the health hazard, many research groups around the world are seriously looking into the matter. Recently, it is reported that foot plantar pressure can be used to asses gait stability and risk of fall. In addition, foot clearance above ground/floor during gait is also reported to be related to the occurrence of fall among the elderly. This is especially true when the foot is swaying on the air, or also called swing phase. Notably, pressure is measured when the foot is already touching the ground, which is known as stance phase, while clearance is measured during mid-swing to heel strike. If both pressure and clearance parameters of gait analysis are used together in an integrated manner, a better way of fall prediction and prevention can be produced. In addition to assessing balance, the measurement of foot plantar pressure and foot clearance are also useful in many other gait assessments. This foot pressure measurement has wide applications, for example in screening for high risk diabetic foot ulceration, design of orthotics for diabetes mellitus and peripheral neuropathy, footwear design, sports injury prevention in athletes, study of the development of gait among the children plus many more. It also can be used to identify gait events such as heel strike, toe off, the timing of swing, stance, stride, the double support phase and also cadence. If stride length is known,