RENEE MONTAGNE, HOST:
And now to a scientific advance - scientists say they have restored a paralyzed man's sense of touch. NPR's Jon Hamilton reports on the technology that's allowing this man to feel again using a robotic hand.
JON HAMILTON, BYLINE: Nathan Copeland has been paralyzed since he was 18.
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NATHAN COPELAND: In 2004, I wrecked my car, and I broke my neck.
HAMILTON: That's from a video made by the University of Pittsburgh Medical Center after Copeland agreed to take part in an experiment. Robert Gaunt, a researcher at the University of Pittsburgh, says Copeland was a good candidate because he can't control his fingers or feel what they touch.
ROBERT GAUNT: With Nathan, his hand has been disconnected from his brain because of his spinal cord injury. But the brain hasn't lost its ability to feel.
HAMILTON: It just needs a signal, so researchers began looking for a way to send that signal. Gaunt says the first step was to monitor Copeland's brain activity.
GAUNT: And we were able to see the parts of his brain that became active when he was watching videos of a hand being touched.
HAMILTON: Then the team placed electrodes in his brain that could stimulate those precise areas. Gaunt says it was several weeks before the team sent the first tiny pulse of electricity to the electrodes in Copeland's head.
GAUNT: When it finally happened, he just very calmly said yup, I felt it on my index finger. And he was very calm and nonchalant about it all. But in the background, I was breathing a sigh of relief. And other people were cheering (laughter).
HAMILTON: The real-world test came when the team connected Copeland's brain to a robotic arm that had sensors in each finger. Copeland says he was immediately able to feel something.
COPELAND: It's a really weird sensation. Sometimes, it feels kind of, like, electrical. And sometimes, it's more of a pressure.
HAMILTON: Gaunt says when Copeland is connected to the robotic arm, he now has a rudimentary sense of touch.
GAUNT: He can tell us how intense it is. Does it feel hard? Does it feel soft? But, you know, we're really not at the point where we could say, get him to feel the difference between silk and burlap or anything like that. Even so, any sense of touch is useful. Mike McLoughlin is an engineer at the Johns Hopkins University Applied Physics Laboratory, which made the robotic arm Copeland uses. It's part of a project funded by the military. McLoughlin says we depend on touch every day, though we rarely think about it. He says, imagine using a prosthetic arm to drink coffee from a Styrofoam cup.
MIKE MCLOUGHLIN: Without sensory feedback, somebody would actually, you know, have to look at the prosthetic, look at the cup, start to close the hand, visually see - OK, the cup's starting to deform...
HAMILTON: And relax their grip before crushing it. McLoughlin says adding even a basic sense of touch makes tasks like this much easier.
MCLOUGHLIN: We're on the verge of something here that's going to, you know, transform lives.
HAMILTON: Of people who are paralyzed or who have a wide range of other disabilities. The results appear in the journal Science Translational Medicine.
Jon Hamilton, NPR News.
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