Stroke is a leading cause of death and disability worldwide. One of the most common impairments caused by stroke is hemiparesis, which is characterized by weakness on one side of the body. Hemiparesis can affect walking, and people with hemiparesis often have difficulty taking long, even steps.
A new device called the Moterum iStride Device™ is designed to help people with hemiparesis improve their walking. The shoe is a passive, portable, wearable device that moves the nonparetic foot backward while the individual walks over ground. The backward motion of the shoe is generated passively by redirecting the wearer’s downward force during stance phase. The motion is generated by the wearer’s force, which allows easier adaptation to the motion, but this also causes the speed to vary slightly from person to person.
The Moterum iStride Device™ helps with gait relearning in several ways. First, the backward motion exaggerates step length asymmetry such that some of the resulting spatiotemporal aspects of gait will be more symmetric once the shoe is taken off. This can be thought of as a version of error augmentation where the asymmetric step length is exaggerated. Secondly, the motion of the shoe encourages the use of the paretic side by making it harder to walk on the nonparetic side. Thirdly, it is untethered and portable, so it enables rehabilitation in a variety of locations. Making rehabilitation available in more locations should improve the context-dependent learning so patients are relearning gait in the same places that they will generally be walking. This context should also help generalize the knowledge to real-world scenarios instead of just the laboratory setting. Fourthly, the device could enable patients to work on their gait in their own time and at their own pace.