Left to right: Tim Hemmes, Michael Boninger, Andrew Schwartz, Wei Wang, Mike McLaughlin
Tim Hemmes, of Butler, Penn., has been paralyzed from the neck down for eight years following a motorcycle accident. He is able to speak normally and looks like a regular, if thin, 31-year-old, sitting about a foot taller than the scientist around him because of his mobile chair. His arms have been resting at the sides of that chair for eight years.
Then on October 2011, he thought about reaching out to his girlfriend? and a robotic arm next to him extended and did it.
In the second panel of the 2012 Popular Mechanics Breakthrough Awards, Wei Wang, Michael Boninger, and Andrew Schwartz of the University if Pittsburgh talked to PM contributing editor Logan Ward about their newest success in developing a brain-computer interface, or BCI, which finally allowed Hemmes to move again, if through a robotic prosthesis.
"The doctor was asking me why I wanted to be the subject of this trial," Tim Hemmes says, "and I said, I was happy with my life, raising my daughter, rescuing pit bulls, but I still remember what everything feels like. She was drinking from a water bottle, and I remembered exactly what it felt like to wrap my fingers around that bottle, to feel the crunch of the thin plastic. I wanted that feeling back."
The BCI concept, first brokered 40 years ago, was largely confined to the realm of possibility until this group of doctors and engineers made a leap forward into reality last October. "It worked. All this hard work and it worked," remembers Boninger, the lead physician on the trial.
BCIs were first mentioned in scientific literature in the 70s. Six years ago PM gave a Breakthrough award to Brain Gate, the first project to have real world success by training a patient to control the movement of a cursor on a screen with his mind. In 2010 a version of that device became commercially available, leaving the Pitt team to figure out how to build on it.
"The only way I know what?s going on in the place between your ears is by how you move," Schwartz, neurobiologist and another leader of the team, says. Schwartz has been working to decode brain activity for decades. But only now has he and his team developed the ability to take in signals from many neurons at once. "When you move, billions of neurons are at work at once," Schwartz says. He compares it to listening to the roar of the crowd from outside a stadium ? you hear the whole attitude, but not individual voices.
Boninger, like many involved in the project, is a doctor and engineer, at the nexus of medicine and engineering. The two groups could collaborate on research more often, according to him. "They don?t talk enough, but when they do great stuff happens." In the case of a spinal cord injury like Hemmes suffered, the mind can generate a thought of movement, but the signal can?t travel past the break in the cord. The Pitt team fused many fields of science to decode the neural signals of a thought and restructure it into a robotic command, bypassing the spinal injury. And they had only 30 days before Hemmes?s brain implants would be taken out.
Hemmes remembers the first day he moved the arm. He watched it move on its own for a while, then, with all the researchers standing around, they finally plugged him in. "I was just thinking, and the arm moved, and then the room erupted. People were calling DARPA and DC."
That moment was the result of a grueling training regimen?two two-hour sessions per day six days a week, in which Hemmes moved a virtual ball around a 3D screen with his mind so doctors could parse his brain signals. "Trying to move something you can?t move is mentally exhausting," he says.
Boninger says: "In 14 days this project took off. If we had a year, what could we accomplish?" He expects a clinically useful device resulting from the research to be available in 5 to 10 years. "We?re building off of what we have, which is something that really happened." But until they can achieve meaningful sensory feedback from the arm, he doesn?t think it is good enough for patients at large. "Movement is great, but sensation is exponentially more beautiful."
Mike McLaughlin, an electrical engineer at Johns Hopkins University, led the team of engineers in what was originally a separate project?the DARPA-funded robotic arm, which has 26 degrees of freedom. Although the technology for below-the-knee prosthetics is very advanced, most upper extremities amputees still wear a hook. "We wanted to create an arm that could move individual fingers, and lift 40 to 50 pounds," says McLaughlin.
The arm was hooked up to an electrocorticography grid?small metal disk electrodes laid on top of Hemmes?s brain. "It?s actually very simple technology, used for 50 years," says Wei Wang, a doctor and engineer who oversaw the day-to-day project. The same basic method has been used to gather brain activity from seizure or epilepsy patients. "It?s basically a translator, turning neural activity into a robotic command," says Wang.
The next step is to graduate to flexible materials for the brain implants, which could be left in permanently.
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