By Joshua Melvin, AFP
PARIS — A decade after a bike crash that left an American man paralyzed from the shoulders down, he can again feed himself, researchers hailing a medical first reported Wednesday. The remarkable advance hinges on a prosthesis which circumvents rather than repairs his spinal injury, using wires, electrodes as well as computer software to reconnect the severed link between his brain and muscles. “To our knowledge, this is the first instance in the world of a person with severe and chronic paralysis directly using their own brain activity to move their own arm and hand to perform functional movements,” lead study author Bolu Ajiboye of Case Western Reserve University in the United States told AFP. The study’s only patient, 56-year-old Bill Kochevar, has two surgically implanted clusters of electrodes — each no bigger than a baby aspirin — in his head to read his brain signals, which are interpreted by a computer.
His muscles then receive their instructions from electrodes in his arm. After around ten years of immobility, this has allowed Kochevar to sip coffee, scratch his nose and eat mashed potatoes in laboratory tests. To overcome gravity that would otherwise prevent him from raising his limb, Kochevar uses a mobile support, which is also under his brain’s control, according to the study published in The Lancet medical journal. Though the prosthesis remains experimental, the researchers hope their work will one day help people with paralysis do daily tasks on their own. ‘Groundbreaking, but’ Scientists are seeking, but have not found, a way to mend spinal cord injuries that result in paralysis. In the meantime, they are developing work-around solutions that reconnect the brain to the body’s muscles. Previous efforts have also used prostheses. One reported on last year was linked to electrodes on the skin that helped an American man, Ian Burkhart, with less severe paralysis open and close his hand, the authors said.
Other methods allow participants to control a robotic arm using their thoughts.
For Kochevar the process of learning to use the prosthesis started by him practicing with a simulation of an arm that appeared on a screen. From there he quickly progressed to using his mind to direct the movements of his arm.