The Pentagon's research arm has achieved another breakthrough in a project designed to revolutionize the technology behind prosthetic limbs and potentially help wounded troops.
The Defense Advanced Research Projects Agency this month announced that a 28-year-old man paralyzed for more than a decade from a spinal cord injury was able to feel physical sensations through a robotic hand wired to his brain.
The work builds on previous research in which a quadriplegic woman with a pair of pea-sized electrodes implanted onto her left motor cortex -- the area of the brain that controls movement -- used her thoughts to direct a robotic limb to grab a cup, shake hands and eat a chocolate bar.
The latest patient, who hasn't been identified, broke new ground by having electrode arrays also placed on his sensory cortex -- which identifies sensations.
"We've completed the circuit," Justin Sanchez, Darpa program manager, said in announcing the most recent results of the Revolutionizing Prosthetics program earlier this month at a conference in St. Louis, according to a press release from the agency.
"Prosthetic limbs that can be controlled by thoughts are showing great promise, but without feedback from signals traveling back to the brain it can be difficult to achieve the level of control needed to perform precise movements," he said. "By wiring a sense of touch from a mechanical hand directly into the brain, this work shows the potential for seamless bio-technological restoration of near-natural function."
The mechanical hand developed by John Hopkins University's Applied Physics Laboratory contains sophisticated torque sensors that can detect when pressure is applied to any of its fingers, then convert those physical changes into electric signals and route them to the electrode arrays, according to the release.
Here's how the agency described the experiment:
In the very first set of tests, in which researchers gently touched each of the prosthetic hand's fingers while the volunteer was blindfolded, he was able to report with nearly 100 percent accuracy which mechanical finger was being touched. The feeling, he reported, was as if his own hand were being touched.As Sanchez told us in an interview earlier this year, his office works to identify potential civilian patients for the program. The agency doesn't perform experiments on troops, even though the research is designed to help those who serve.
"At one point, instead of pressing one finger, the team decided to press two without telling him," said Sanchez, who oversees the Revolutionizing Prosthetics program. "He responded in jest asking whether somebody was trying to play a trick on him. That is when we knew that the feelings he was perceiving through the robotic hand were near-natural."
"Military personnel make the ultimate sacrifice," Sanchez said. "They serve our nation and their lives often are changed through their injury. The very least we can do is develop a technology that will help to improve their quality of life. We have to stay true to that. It's essential."