Image courtesy of ReWalk
When someone suffers a stroke, he or she often loses some mobility, and some 60 percent of survivors are left with lower-limb deficits. “They usually have one leg that's more impaired than the other leg, and then they undergo rehabilitation and physical therapy. And often they don't fully recover,” said Conor Walsh, professor of engineering and applied sciences at the John A. Paulson Harvard School of Engineering and Applied Sciences and a core faculty member at the Wyss Institute for Biologically Inspired Engineering, in an interview with MD+DI.
But a new device called ReStore, developed by ReWalk, may help stroke survivors learn to walk better. ReStore is a powered, lightweight, soft exo-suit for use in gait training in people with lower-limb disabilities. The device has been submitted for review by the U.S. FDA and for review in the European Union. (Read our previous coverage of the prototype here.) ReWalk had previously received FDA clearance for its ReWalk Personal System, an exoskeleton for patients with spinal cord injuries.
The patient wears the device in a waist pack, which holds two motors, each with a cable that goes down to the foot and ankle. The cables then extend to a foot plate under the shoe. Sensors clipped to the patient’s shoes detect motion and communicate to a smart phone controller when the user needs assistance in moving the foot. Using data analytics displayed on the smart phone, a therapist can adjust the assistance level, monitor key metrics, and record standard gait-training assessments.
“Let's say the [patient’s] right leg was affected more, they’ll take a step with the left leg, then they’ll take a step with the right leg and receive propulsion assistance, the level of which can be controlled by the therapist with a smart phone controller,” said Andy Dolan, vice president of marketing, ReWalk. “Sensors on both feet actually pick up the timing to help the person walk more symmetrically, having one leg look like the other leg [that is] less affected by the stroke.”
Walsh said that one of the key innovations of ReStore is the ability to apply force to the body, but not restrict how a person moves. “The idea of anchoring the body with textiles and flexible soft components is a fundamentally new way of applying assistance with a wearable robot,” he noted. “And the other innovation is the algorithm. We want to make sure that we're allowing the person to remain in control and we're applying assistance on a step-by-step basis in a way that adapts to how a person walks,” he continued. “The person is always fully in control, and the system is only helping them when they need help.”
ReStore is designed to be fully compatible with all the typical activities associated with gait therapy. “Because it's a very nonrestrictive and lightweight device, a therapist can put this on a patient and they can go through all their normal [gait therapy] activities, and the ReStore system will just help make those better,” said Walsh.
The first use of ReStore with be with patients with lower limb deficits, but there are other potential applications for the device, Walsh said. “The ReStore system focuses on the ankle joint, but we think that it's possible to have hip systems that could also be applied to stroke survivors,” he said. “And we have some research going on at Harvard at the moment exploring how the technology could fit with MS and also how it could fit with Parkinson's disease, and we're also interested in is uses for the elderly. That's the ongoing research that we hope in the future will lead to additional products based on the exo-suit technology.”
All requirements for submission to FDA and the EU have been completed and are under review. “Our general forecast is that around mid-year we should be selling ReStore in both United States and Europe,” said Larry Jasinski, CEO of ReWalk. “I view this as a Main Street product. The exo-suit is built around local therapy, near-your-home-type centers, all over the United States, that will be able to bring this technology in,” he said. “We believe any local rehab clinic would find this beneficial.”