"Imagine all the joints that are in your hand. There's 20 motions around all those joints," says Pittsburgh neurobiologist Andrew Schwartz. "It's not just reaching out and crudely grasping something. We want them to be able to use the fingers we've worked so hard on."
Just when that might happen is an open question, Schwartz said, but it could be in the next couple of years, with prostheses or free-standing robotic arms on the market a few years after that.