A Microcontroller based Bio-mimetic Stimulation Envelope for Correction of Drop-foot in Hemiplegics using Functional Electrical Stimulation

摘要

A low-cost, programmable, single channel stimulator for patterned electrical stimulation has been developed. The prototype is small, light in weight, battery-operated, and flexible for foot drop application. A microcontroller is used for control of charge compensation, pulse rate and duration, as well as generating "natural patterns" of stimulation envelope and functional use regimes. During normal gait, the electromyographic (EMG) signal from the tibialis anterior (TA) muscle indicates that muscle force varies during the swing phase. The traditional trapezoidal/square stimulation intensity approach is inconsistent with the muscle activity patterns and therefore unsuitable. The objective of this paper was to provide more natural stimulation intensity envelope which is expected to accurately reproduce the natural TA EMG profile generated while walking speed of hemiplegic patients for thecorrection of drop foot which may enhance the gait by generating greater torque at the ankle and thereby increase the efficiency of the stimulation with reduced fatigue.