It's a small but hopeful step: A man paralyzed from the neck down due to a spinal injury sustained in a 2004 car accident says he's feeling "possibly natural" sensations in his hand after scientists electrically stimulated his brain. A team led by researchers at the University of Pittsburgh implanted four microelectrode arrays in then-28-year-old Nathan Copeland's brain and "linked [them] to a robotic arm in the same room via a computer," New Scientist explains. When touched, the goal was to have the bionic hand essentially trigger a response in Copeland’s brain, and it worked. "He feels these sensations coming from his own paralyzed hand," one researcher tells New Scientist. The team was particularly excited by the consistency across what Scientific American reports were 6 months of experiments described in a study published in Science Translational Medicine.
Copeland described the sensation as "possibly natural" 93% of the time, and over the course of 190 trials intended to measure quality, 67% involved the feeling of pressure, 15% of warmth (like "a shot of vodka, that warm but not like holding-a-cup-of-coffee warm," Copeland says) and 15% of electrical stimulation. When specific fingers were targeted, he identified which one correctly 84% of the time, though he couldn't discern an item's texture, and New Scientist notes he didn't register feeling in his thumb or fingertips, which is a barrier to getting Copeland to the point where he could grip an object. TribLive reports Copeland began using the robotic arm in November 2014, and expects to participate in the study for 4 more years. When it ends, he'll have to give up the arm. (Artificial skin is advancing, too.)