AbilityRoboCart: Design and Implementation of Overground Robotic Gait Trainer for Individuals Post-Stroke

This study aimed to design and develop the AbilityRoboCart, a robotic gait trainer, and assess its potential to enhance the use of the paretic leg while minimizing compensatory strategies in the non-paretic leg of post stroke individuals. The main focus was to investigate whether the application of constraint force, delivered either gradually or abruptly using an overground robotic gait trainer to the nonparetic limb in the posterior direction during overground walking, could improve the use of the paretic leg in individuals with chronic stroke. Four individuals after stroke participated in two experimental conditions, overground walking with a gradual constraint force applied to the nonparetic leg and overground walking with an abrupt constraint force applied to the nonparetic leg. The force application was carried out with a novel technology—an overground gait trainer named AbilityRoboCart—specifically designed for post-stroke individuals. The core idea behind the device is to apply a resistive force to the non-paretic leg during the early swing phase of gait, achieved through a mechanical system, particularly employing a cable and pulley system. The real-time application of this constraining force is regulated by the kinematics of the foot. To facilitate seamless communication with the AbilityRoboCart software throughout the experimental protocol, each participant is equipped with inertial sensors. These sensors enable the continuous monitoring and adjustment of the resistive force in real-time. Participants recruited were tested in the following procedures that consisted of overground walking with either constraint force, instrumented split-belt treadmill walking, and pressure sensitive walking on walkway GaitRite before and after the overground walking with the gait trainer. Practicing overground walking with the constraint force resulted in greater enhancement in the propulsion force of the paretic side for half of the participants, while the remaining participants exhibited a pronounced enhancement in the braking force. Those who showed improvement in the propulsion force of the paretic side (P< 0.01), muscular activity of hip abductor (P< 0.02) during early-mid stance and mid-late stance phase and increase in the muscular activity of ankle plantarflexors (P< 0.01) also showed an improvement in the propulsion asymmetry and in their overground walking speed in both application of the force conditions. Overground walking sessions with constraint force tended to induce a more substantial increase in self-selected overground walking speed (+0.08 m/s) than the no-constraint effect. Applying constraint force to the nonparetic leg during early swing phase of gait in overground walking may enhance use of the paretic leg, improve propulsion force of the paretic side and muscle activity in hip abductors and plantarflexors of the paretic leg, and consequently increase walking speed.