Micera cautioned that it will take several years of additional research to create a first-generation artificial hand that can feel, and looks more like a traditional prosthetic. First, they have to prove these nerve implants can last; for safety reasons, Sorensen’s were surgically removed after the experiment.
But a lot of work is under way.
In Ohio, Tyler’s team recently issued video showing a blindfolded man gently pulling stems from cherries without crushing them, thanks to similar implanted nerve stimulators and a sensor-equipped prosthetic hand. The main difference, said Switzerland’s Micera, is in how the nerve electrodes are implanted. The European approach puts them inside the nerve rather than around it for better control, but that’s more invasive and some researchers worry it could damage the nerve over time.
In Pittsburgh, Schwartz’s team is about to test another approach — a brain-controlled robotic hand for the paralyzed that would “feel” through electrodes implanted in a brain region known as the sensory cortex.
Whatever the approach, touch is a complex sense and these are all basic first steps involving how someone grasps, not more sophisticated sensations such as texture or temperature.
“There is definitely tremendous value to having a sense of touch, a sense of feeling from the hand,” said Case Western’s Tyler. “What that feeling is, how we use it — that’s yet to come.”