WASHINGTON (Talk Media News) – Johnny Matheny wears a prosthetic arm that’s integrated with his body, he thinks and the mechanical arm anchored to his humorous bone responds accordingly.
“We had metal hooks and we had these kind of low tech solutions. We said ‘nope, we don’t want any of that.’ We want arms that have the same size, shape, grip strength as an adult human arm,” said Justin Sanchez, director of the Biological Technologies Office at the Defense Advanced Research Projects Agency (DARPA).
DARPA launched the revolutionizing prosthetics program in 2006 and, in partnership with the Johns Hopkins University Applied Physics Lab, developed the prototype arm. It’s the world’s most advanced prosthetic arm, according to Sanchez.
“The idea was to be able to connect the brain to the prosthetic in a way that allows us to move the prosthetic much like we move our natural limbs,” said Michael McLoughlin, the chief engineer at the Research and Exploratory Development Department at Johns Hopkins University Applied Physics Lab.
“The prosthetic learns how to understand what you want to do as opposed to you learning how to operate the prosthetic.”
McLoughlin explained that the Myo armband Matheny wears around his upper arm picks up electrical signals from residual limb nerves. Those signals are transmitted via Bluetooth to a computer inside the prosthetic arm, which translates the signal and drives motors inside the device.
Matheny, 61, lost his arm to cancer in 2008, and was unable to return to work as a bread sales and delivery man. With three children who enlisted in the service, he wanted to use his body to give back.
He joined the DARPA project in 2011, receiving the nerve rerouting procedure, called targeted muscle reinnervation (TMR). In 2015 Matheny became the first American with TMR to undergo osseointegration, a surgical procedure that allows him to connect prosthetic devices directly to the bone of his upper arm.
“Before, with a traditional prosthetic, I couldn’t even drink a glass of water, couldn’t feed myself,” Matheny said, describing the prosthetic’s mobility. “Now, with this, you get the hand all the way up to the mouth. You can do anything.”
The arm Matheny wears is capable of detecting texture, pressure and temperature. In order for him to feel what his prosthetic feels, however, the sensation has to be routed back to his brain — a feat that could come in the not to distant future — creating a closed circuit that melds synthetic and biological wires.
DARPA wants to push the concept further, replacing the wearable Myo armband that sits atop the arm with sensory implants.
Implanted devices are already being tested in humans, and so far have shown promise — restoring the sense of touch and reducing the phantom limb pain experienced by many amputees.
The robotic arm could not only help soldiers returning from service without a limb, but also those with any other type of mobility hindrance because of nerve damage, routing a signal directly from the brain’s somatosensory cortex to the prosthetic and back.
The dexterous hand capabilities developed under the program also have been applied to small robotic systems and used to diffuse unexploded ordnance, according to DARPA.
The arm Matheny wears is not FDA approved, but one created by DEKA Research & Development Corporation in partnership with DARPA is. DEKA’s arm doesn’t operate in the same way, however, using more traditional technology to move the prosthetic.
Matheny only uses the prosthetic during laboratory testing or public demos every few months, going without a left arm at home. But, he said that he’ll soon be able to bring it home to use daily.
“If you think it looks amazing now, can you imagine what it’s going to look like day in and day out?” he said.