Stroke is the leading cause of serious long-term disability in the US with approximately 17 million individuals experiencing it each year. About 8 out of 10 stroke survivors suffer from “hemiparesis”, a paralysis that typically impacts the limbs and facial muscles on one side of their bodies, and often causes severe difficulties walking, a loss of balance with an increased risk of falling, as well as muscle fatigue that quickly sets in during exertions.
Using an untethered version of the exosuit that carries its own battery and motor, they showed in a cohort of six post-stroke survivors with hemiparesis that their device could significantly increase individuals’ walking speed by an average 0.14 meters per second, with one individual walking as much as 0.28 meters per second faster. These same individuals, when asked to walk as far as they can in 6 minutes, were able to go 32 meters farther, on average, with one person traveling over 100 meters farther.
The exosuit deployed in this study weighs less than five kilograms and targets the limbs of stroke survivors during distinct phases of the gait cycle. Fully mobile, it is powered by a battery and initiated by an actuator unit both worn at the hips. It delivers mechanical power to the ankles via a cable-based mechanism, whereby the cables and other parts of the exosuit are anchored to the body by lightweight functional textiles. Adding further to its low weight and potential to reduce gait asymmetries is the fact that patients wear it only on the impaired paretic side, unlike rigid exoskeleton systems – many of which need to be worn on both sides.