How a Paralyzed Man Learned to Move Again

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June 27 2014 12:36 PM

The Quadriplegic Who Moved His Hand

Could brain implants spell the end of permanent paralysis?

Ian Burkhart was 19 and fearless and horsing around in the surf with friends on vacation in North Carolina’s Outer Banks when he mistimed a dive and a wave drove him headfirst into a sandbar.

Will Oremus Will Oremus

Will Oremus is Slate's senior technology writer.

“I knew instantly when I hit,” he says. “You’re facedown in the water and you’re trying to get up and all of a sudden you realize that you can’t move.” His friends hauled him safely onto the beach, but Burkhart was paralyzed.

The former high school lacrosse goalie spent five weeks in a hospital on a ventilator recovering from the water he had inhaled and processing the news that he was now a quadriplegic. Growing up in suburban Columbus, Ohio, the third child of four, Burkhart had always been self-sufficient—the kid who insisted on doing his own laundry in middle school, who started a landscaping business in high school, and who was out at all hours the moment he got his driver’s license. Now his dreams of becoming a video editor looked as dead as his lacrosse career.

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But from the start, Burkhart, now 23, had faith that 21st-century medicine could come to his aid. “One of the things that has helped me mentally ever since the accident is the fact that science and technology are growing and succeeding at such a rapid rate,” he says by phone from his family home in Ohio. “I always knew there was going to be something. I just didn’t know what or when.”

So when he was offered the chance to participate in a first-of-its-kind experiment at Ohio State University, he latched on to it, even though it meant brain surgery—and even though it came with no guarantee of improving his life.

The experiment was this: Working with researchers from Battelle, a Columbus nonprofit focused on scientific research and development, Ohio State surgeons would implant a small array of electrodes in Burkhart’s motor cortex. Then they’d wire his brain to a computer, which in turn would be wired to a specially designed sleeve on his arm. If all worked as planned, the contraption, called Neurobridge, would function as a sort of crude substitute for his spinal cord, harnessing and translating the signals from his brain to stimulate the muscles in his arm. In other words, Burkhart would be able to control his hand with his mind—which sounds outlandish until you realize it’s exactly what able-bodied people are doing all the time.

The difference is that the human spinal cord evolved in concert with the brain over eons to seamlessly transmit its impulses to our limbs. The technology to monitor and decode people’s neural activity—that is, to read their minds—is in its infancy. To make it work at all requires a grueling regimen of hospital visits and training sessions. To make it work well, at least at this point (or even to make it work at all outside of a hospital session), is out of the question.

The researchers at Battelle and Ohio State explained this to Burkhart. “It definitely was a big time commitment that I had to worry about,” he says. He’s pursuing a bachelor’s degree in business from Ohio State and Columbus State, and he coaches lacrosse at Dublin Jerome High School, his alma mater. “And then there’s the fact that you’re basically signing yourself up for elective brain surgery that you don’t need,” Burkhart adds.

He thought hard about the serious risks and limited rewards—and decided to do it anyway. “I really couldn’t pass up the opportunity to be part of something that might help other people in the future.”

140626_TECH_BrainHand
Doctors and researchers watch intently as Ian Burkhart becomes the first patient to move his paralyzed hand using groundbreaking technology called Neurobridge.

Photo courtesy Ohio State University Wexner Medical Center

Burkhart isn’t the first paralyzed person to get a chip implanted in his brain.  Pioneered on monkeys, brain-computer interfaces have been used in recent years to allow people with paralysis, Lou Gehrig’s disease, and even locked-in syndrome to control computer cursors or robotic appendages with their minds. A team at the University of Pittsburgh made headlines in December 2012 when it helped a quadriplegic woman named Jan Scheuermann feed herself chocolate with a robotic arm.

Those successes paved the path for Battelle to try something new with Burkhart: a system that would give patients control over their own limbs, rather than artificial ones. In the long run, it could prove less pricey and cumbersome, and it might have wider medical applications. In a three-hour operation on April 22, Ohio State neurosurgeon Ali Rezai opened Burkhart’s brain and implanted an electrode array a little smaller than a pea. Then the real work began.

To say that the software can read Burkhart’s mind is a little like saying that a first-year Latin student can read Catullus. Without a dictionary. And with most of the text missing.  

First of all, the sensors can only pick up signals from the tiny sampling of neurons that immediately surround them. The rest of the brain’s activity remains unreadable, beyond reach. And there’s no preset cipher for the signals they do pick up. Instead, a semblance of understanding between man and machine emerges gradually, through mutual effort.

It starts with Burkhart thinking as hard as he can about performing a certain task, like clasping his hand. (Figuring out exactly what to think about is trickier than it sounds, Burkhart notes. Back when he actually could clasp his hand, he never had to think about it.) As he concentrates, the sensors in his brain send data to a computer for analysis by specially designed machine-learning software. Over time, the software works to pick out an identifiable pattern of activity that corresponds to Burkhart trying to clasp his hand—and then, eventually, to differentiate that from the pattern that corresponds to Burkhart trying to unclasp his hand, or turn it over, or use it to wave hello.

On the software end, there are really three distinct problems to solve, explains Battelle’s Chad Bouton, leader of the Neurobridge project. The first is implanting the chip in the right part of the brain to decode the neural signals. The second is using software to decode those signals. And the third is recoding them and sending them to the sleeve to electrically stimulate the patient’s muscles in the appropriate ways. “We’re basically creating what we believe is going to be a virtual spinal cord,” Bouton says.

Crucially, though, it isn’t just the software that’s learning. Burkhart, for his part, learns by trial and error how to focus his mental activity in a way that the software can understand. That wouldn’t be so hard if the only goal were to reliably perform a single movement, like tapping a single key on a keyboard. But it becomes exponentially more difficult when the goal is to simultaneously modulate the movements of multiple digits and string them together into specific patterns. Add in the fact that he still can’t feel anything in his hands—he can control them, but there’s no sensory feedback mechanism—and Burkhart says he’d be “shocked” if he could pull off something as complex as typing on a keyboard anytime soon.

In the end, the process isn’t so much like one person learning a foreign language. It’s more like two people who speak different languages inventing a new one they can both understand.

For Burkhart, the experience has been as fascinating as it is exhausting. “The guys I’m working with, between the doctors at OSU and the researchers at Battelle—they’re ridiculously smart,” he says. “I have learned a lot just going into those sessions and kind of being a fly on the wall. It’s pretty amazing that I can give them feedback and be a part of it.”

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This photo captures the moment a paralyzed man moved his hand for the first time using his own thoughts.

Photo courtesy Ohio State University Wexner Medical Center

This week, two months after Burkhart’s surgery, Ohio State and Battelle went public with their achievements, billing Burkhart as the first paralyzed man to move his own hand with his thoughts. So far he has mastered five discrete patterns of movement: opening and closing his hand, rotating it up or down, moving it up or down with his wrist, and drumming on a table with his fingers, one after the next. Burkhart goes to the hospital and does these things, and he and the researchers rejoice and marvel at how far he’s come, and videographers record it and send news of the achievement to the world, and then he goes home and is immobile again.

There’s one more catch. As Antonio Regalado poignantly documented in a recent feature story for MIT Technology Review, the chips that researchers implant in patients’ brains aren’t permanent. Rather, the sensors’ reach degrades over time. The result is that Scheuermann, the Pittsburgh woman who made headlines just 18 months ago for feeding herself chocolate with a robotic arm, is already losing some of the dexterity she fought so hard to regain.

Burkhart says he knows the chip will have to come out eventually—probably within five years. But he has faith that experiments like his will lead to further technological advances by then. “It’s already pretty crazy what they’re able to do now. But I wouldn’t go so far as to say we’re living in the future. I know just by looking at history that it’s only going to get better.”

That might seem like a safe bet, but as Regalado’s article makes clear, it’s not a certainty. Not only is the technology invasive, expensive, and impractical, but the potential market—that is, quadriplegics—is too small to excite venture capitalists or corporations with the kind of resources needed to develop and commercialize it.

Battelle’s Bouton emphasizes to me that the Neurobridge research is still in its early stages, with approval so far to work with up to five patients. Provided it goes well, he agrees the eventual goal will be to find commercial applications. There’s some hope, for instance, that the technology could be adapted for rehabilitation of stroke victims, of whom there are about a million a year in the United States alone. “It’s a big unmet need,” Bouton says.

Even better than brain implants would be a system that could read people’s brains from outside their skulls, like an electroencephalography headset. So far, however, external EEG headsets’ performance has not matched their hype, because they can detect only the very crudest signals emanating from the brain. That’s why the highly anticipated ceremonial first kick of the 2014 World Cup—taken by a paraplegic with an EEG headset and a robotic suit—ended up being a bit of a letdown. Yet despite the enormous cost and limited practicality of brain-computer interfaces, Brown University’s John Donoghue pointed out in MIT Technology Review that the first pacemakers were similarly unwieldy.

Burkhart, for his part, is eager to be a spokesman for the technology—which, of course, is exactly what researchers need if they want to attract more funding. Meanwhile, he’s also asking for donations for his own ongoing medical expenses. Of his paralysis, Burkhart says, “I wouldn’t wish that on anybody, but I really can’t complain about the way my life is right now. If nothing else, I can say I was the first person ever to do something, which is an opportunity I never expected to have.”

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