Electrically Induced Gait Changes Post Stroke, Using an FNS System with Intramuscular Electrodes and Multiple Channels

Abstract

This study investigated the feasibility and benefit of using a multichannel functional neuromuscular stimulation (FNS) system with intramuscular electrodes for stroke rehabilitation. The subject was 46 years old and four years post-left CVA, with right hemiparesis resulting in multiple gait deficits that were unchanged for two years prior to entry into the study. Ten muscles were implanted with intramuscular electrodes. The stimulator controlled each channel separately, providing adjustable stimulation patterns for FNS exercise and gait training. Outcome measures were gait swing phase kinematics: knee flexion at toe-off ; peak swing knee flexion; and knee extension prior to heelstrike. Tests were conducted during voluntary walking (no FNS), before and after nine months of FNS treatment. Following treatment, the gait pattern was significantly improved for knee flexion at toe-off, peak swing knee flexion, and knee extension prior to heelstrike. Former right swing phase compensatory movements were resolved. With the intramuscular electrodes, it was possible to stimulate specific muscles, obtain consistent muscle response from day to day, and use sufficient stimulus intensity within comfort to obtain a useful therapeutic effect. The microprocessor-based stimulator made possible a well-coordinated movement pattern. These results support the merit of further study of this FNS system for exercise and gait training treatment post-stroke.