On Thursday, at the White House Frontiers Conference in Pittsburg, President Barack Obama shook hands with a remarkable young man. Nathan Copeland, who is now 30, has been paralyzed since his car spun out of control one rainy winter night when he was a teen. But thanks to a new breakthrough in prosthetics, when Obama shook his hand, Copeland could feel it. When they fist-bumped, Copeland could feel that, too.
The sensation of feeling came via Copeland's mind-controlled robotic arm. Last spring, surgeons implanted four tiny microelectrode arrays into the sensory cortex area of Copeland's brain. The prosthetic arm delivers currents to the electrodes that stimulate his brain to create sensations of touch that feel as if they are coming from his own paralyzed hand.
Copeland can control the arm using other chips implanted in a different part of his brain. The whole thing works as a sort of sensory feedback loop: Copeland's brain sends a signal to the robotic arm to move, and the arm then sends a signal back to him. This is, of course, how feelings like touch typically work, but here researchers were able to reroute those signals to a prosthetic limb.
Last fall, DARPA announced that, for the first time, neural technologies developed under DARPA’s Revolutionizing Prosthetics program had allowed a patient to "feel." The University of Pittsburgh research that Copeland was a part of was funded by the same DARPA program. Copeland's prosthesis is the first time that such a technology has worked for an extended period of time, outside of a lab.
“I can feel just about every finger,” Copeland told The Washington Post. “Sometimes it feels electrical, and sometimes it's pressure, but for the most part, I can tell most of the fingers with definite precision. It feels like my fingers are getting touched or pushed.”
The number of things that Copeland can feel are still minimal. He can feel pressure with exactness, but cannot sense, for example, whether something is hot or cold.
“With Nathan, he can control a prosthetic arm, do a handshake, fist bump, move objects around,” study author Robert Gaunt told the Post. “Now we want to put those two things together so that when he reaches out to grasp an object, he can feel it. … He can pick something up that’s soft and not squash it or drop it.”
The goal is to eventually make using a prosthetic limb feel completely natural. But there are hurdles. For one, we don't understand everything about the regions of the brain that control all of the sensations of touch that researchers would eventually like to restore.
In the meantime, though, Nathan Copeland didn't just get to fist bump the president—he got to feel it.