Retraining of Human Gait - Are Lightweight Cable-Driven Leg Exoskeleton Designs Effective?

Abstract

Exoskeletons for gait training commonly use a rigid-linked "skeleton" which makes them heavy and bulky. Cable-driven exoskeletons eliminate the rigid-linked skeleton, providing a lighter and transparent design. Current cable-driven exoskeletons are aimed only at gait assistance by providing short bursts of forces to the leg during walking. It has not yet been shown if these designs are suitable for gait retraining, where rehabilitative forces need to be continuously applied to the leg in response to errors from a desired movement. The goal of this study is to investigate if a cable-driven leg exoskeleton can retrain the gait of human users. Nine healthy subjects were trained by a cable-driven leg exoskeleton to walk in a new gait pattern with 30% increase in step height from their natural gait. After 40 min of training, the gait of the subjects became significantly closer to the target gait than before the training. In three different post-training sessions, the step height of the subjects increased by 22%, 29%, and 31% on an average. In a fourth post-training session, when the subjects were instructed to ignore the training and walk naturally, the step height remained increased by 11%. These results confirm the potential of cable-driven designs in gait training applications.