CAMBRIDGE, Mass. — For hours on end last year, Massachusetts Institute of Technology engineers ran the brain-controlled robotic limb through its paces, testing its capabilities on a series of patients and fine-tuning it like a pit crew preparing a race car for the Indy 500.
They had patients flex the prosthetic foot: toe up, toe down. Toe in, toe out. Walk up a flight of stairs, then back down. But it was after the day’s experiments, when patient Jim Ewing was seated and chatting with the team, that they made their most provocative observation: He fidgeted, pivoting the motorized ankle, unconsciously.
It wasn’t much, just a wiggle now and then, but it provided powerful evidence that the new robotic foot had become a seamless part of Ewing’s body in a way that has never been accomplished before with a prosthetic limb, the scientists reported Wednesday.