With an existing analog (or even powered) prosthesis, there's often an infuriating lag between intention and action because the user has to physically contract a muscle to activate it. Not so with the IMES system. When electrical signals from the user's brain hit the end of the amputated leg, they're picked up by a pair of sensors embedded in the surrounding muscle tissue. These sensors, in turn, send a wireless signal to the Proprio foot telling it to flex or extend. And since the muscles themselves aren't contracting, there's no lag between thinking about moving and actually doing so. What's more, the implantation surgery only takes about 15 minutes and requires an single single-centimeter-long incision. Even cooler is the fact that the sensors are powered by tiny magnetic coils housed in the prosthetic socket so they won't have to be replaced once installed. "We believe this is a lifelong sensor," Thorvaldur Ingvarsson, Ossur's head of R&D, told Popular Science.
"It's really surreal," Gudmundur Olafsson, one of the the company's two initial test subjects, said in a statement. "The first time, to be honest, I started to cry. You are moving the ankle, and I basically haven't had one in 11 years." Olafsson spent 14 months using the IMES-enabled Proprio as his sole prosthetic.
Up next, the company plans to hold large-scale clinical trials and hopes to have the device to market within the next three to five years. There's no word yet on how much the devices will cost once they do become available.