LUKE'S LIMB

Soon, we’ll be able to control robot limbs with our minds, like Luke Skywalker

In the future, limbs may be disposable.

In 2014, a robot arm that connects into the electrical activity in muscles was approved for commercial sale by the US Food and Drug Administration. The arm allows amputees to do things like climb walls and eat sushi, albeit a little slowly. It was created by DEKA, the company founded by Dean Kamen (the man behind the Segway), and funded by the US Defense Advanced Research Projects Agency.

Now DARPA wants to develop this technology into something that can be controlled by the brain, as easily as a human arm, by amputees, quadriplegics, or anyone in need of a new limb.

The DEKA arm, in its current form, is about the size and weight as an adult man’s arm. It has the dexterity to pick up a grape without crushing it, and can be controlled by a foot pump, if tapping into’s an amputee’s remaining muscle tissue is not an option. IEEE Spectrum wrote about Kamen’s breakthrough invention in 2008, suggesting that FDA approval would only take a year. Even with DARPA backing Kamen, the device only received approval last year.

Part of DARPA’s interest in the project came from the sheer number of military personnel needing amputations. According to the Congressional Research Service, there have been over 1,500 soldiers who required major limb amputations after tours in Iraq and Afghanistan. That’s on top of the roughly 185,000 amputations that occur in the US each year.

DARPA handout image shows the DEKA Arm System
The current DEKA arm. (Reuters/DARPA)

DARPA only recently structured its funding in biotechnology research into the Biological Technologies Office, in April 2014. Its founding director, Geoffrey Ling, said at DARPABiT—the agency’s biotech conference—in New York June 23, that until recently, the most advanced arm prosthesis commercially available was a piece of plastic with a hook at its end, which wasn’t vastly different from what the wounded soldiers got after the Civil War. “Kids don’t want to grow up to look like Captain Hook,” Ling said.

 “Kids don’t want to grow up to look like Captain Hook,” Ling said. 

Ling led the original team that funded the DEKA arm, and has since handed the task of mind-controlled arms over to Doug Weber. His team is trying to figure out how to make “prosthetic limb systems that feel and function like natal limbs.” The body’s nervous system uses a code—Weber says it is not unlike Morse code—to send signals to move muscles. The team is working on interpreting that code, and will then build a small device that can interpret and send signals.

That device would be implanted in an amputee’s brain, and would be used to sense when the person wanted to move a limb, and then transmit that signal to the robot arm to move.

Speaking at the conference, both Ling and Weber said the program was influenced by Luke Skywalker’s bionic hand from The Empire Strikes Back. While it’s interesting to see that scientists are increasingly influenced by the same cultural touchstones we all enjoy, this work is not purely in the ream of science fiction. Ling’s original team already proved that this concept works—in 2012, they showed off a robot arm that was being controlled by a quadriplegic woman by a small device implanted in her brain.

The next challenge is to create robot arms that also give us the sense of feeling like a real arm would. In Star Wars, we see the doctor (also a robot) pricking Luke’s bionic fingers, which makes him react like an actual part of his body was being pricked. To achieve this, scientists will need to create devices that can sense external inputs and feed them back into the nervous system, not just send messages to the robot limbs. Weber calls this a “closed-loop.”

Weber spoke about taking the concept even further: In the future, scientists could be able to create input devices—similar to the one to control limbs—to control our adrenaline levels, blood pressure, or how our immune responds to an attack. “I want to build technology to access systems that control our nervous system,” he added.

Ling said at the conference that the DEKA arm project was given two years to reach its goal, and that it took longer to get it through the FDA approvals process than to develop. The mind-controlled version will get four years, assuming adequate progress is shown. “We’ll fund it ’til it makes sense,” he said, adding DARPA likes to “fail early, fail fast.”

Unfortunately, however advanced robot arms get, they will likely not change your relationship with your father, ancient religions, or hokey weapons.

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