Man moves prosthetic arm with his mind in proof-of-concept study

BALTIMORE, Feb. 17 (UPI) -- Using his mind, a man moved fingers attached to the hand of a prosthetic arm, which scientists at Johns Hopkins University believe is a first for a person who has not undergone extensive training before doing so.

Scientists said it may be years before technology used in the new proof-of-concept study can be widely applied, but precise mapping of the brain has given them a much greater understanding of how people can interact with prosthetic body parts.

The man in the study, who is not missing a limb, was able to move individual fingers to grab things just by thinking about it, as a result of electrodes implanted in his brain. The enhanced information gained from these electrodes, the scientists said, is what they say makes their study so significant.

"The electrodes used to measure brain activity in this study gave us better resolution of a large region of cortex than anything we've used before and allowed for more precise spatial mapping in the brain," Guy Hotson, graduate student at Johns Hopkins University, said in a press release. "This precision is what allowed us to separate the control of individual fingers."

For the study, which is published in the Journal of Neural Engineering, the scientists recruited a man with epilepsy undergoing brain mapping to identify the origin of his seizures.

Scientists in the study took advantage of the fact that a 128-electrode array of sensors placed in the man's brain for his epilepsy treatment could also control a prosthetic limb developed at the university.

After mapping which parts of the man's brain were responsible for moving each finger, and programming the prosthesis to respond to signals from that part of the brain, the scientists connected the limb and asked him to "think" about moving each of his fingers individually.

The man's accuracy at moving the prosthetic was around 76 percent, until the ring and little fingers were coupled to move together -- because those parts of the brain overlap and people often move the two digits together -- increasing his accuracy to about 88 percent.

Most notable is that the man did not need to be taught to control the system or prosthesis, and the entire experiment took less than two hours, unlike other prosthetics that often take weeks to learn to use and gain accuracy.

Further research into prosthetic technology, computer systems, and much more extensive mapping of the brain are needed before the method can be used with people without limbs, but the potential for it to help people is huge, scientists said.