Researchers at University of California, Irvine have successfully used a paraplegic man’s own legs as thought-controlled prostheses. By bypassing damaged nerves with wires, the test subject–a 26-year-old-man–walked almost 12 feet on his own legs.
After a spinal cord injury, there’s usually little option but to put the injured person in a wheelchair, and this has secondary effects, aside from the whole wheelchair-access issue. Sitting all day leads to obesity, osteoporosis, and other life-shortening problems. But without a connection between an otherwise healthy brain and legs, a paraplegic person has no way to walk.
Using an EEG cap to detect brainwaves, the researchers hooked the subject’s brain up to a computer which uses algorithms to translate brain signals into muscle signals. After 19 weeks of training to get his muscles strong enough to partially support him, and using a virtual-reality training room to verify that the brain signals were being correctly translated, the subject walked successfully, just like anyone else, although with the help of some weight-bearing assistance from a harness support and a walking frame for balance and support.
The interface is basic. The brain doesn’t control movement directly. Instead, the brain issues go and stop commands, and the computer does the actual controlling of the legs, activating them in turn as if they were mechanical prostheses. But the team, headed by Zoran Nenadic and An H. Do, thinks that the same principles could be used to create an implant with much higher “resolution.”
“We hope that an implant could achieve an even greater level of prosthesis control,” Zoran told the Guardian, “because brain waves are recorded with higher quality. In addition, such an implant could deliver sensation back to the brain, enabling the user to feel their legs.”
DARPA has already managed to use sensors in the fingertips of a prosthetic hand to feed back signals to the brain and give the wearer a sense of touch. Could Zoran’s technique be used in the reverse direction, using the subject’s own hands and feet as sensors and sending their signals back to the brain after computer translation?
That’s a long way off. The next step is to expand the test to more subjects to see if the system is viable on a large scale. Only then would “invasive,” or implanted, alternatives be used. The system could also help patients with partial nerve damage, allowing them to strengthen “residual connections between the brain and spinal motor pools,” says the published report.