Two phantoms have come back to life, making their presence felt in the real world. One is a phantom body locked in a paralyzed patient’s mind, which has taken control of a robot arm. The other is a research venture, locked into a company that vanished in the economic disaster of 2008, only to reappear as academic science, supported by major universities, that today scored a dramatic success.
But what’s truly amazing here are the patients, doing what you see in this photo: A woman named Cathy, who hasn’t been able to move anything below her neck for 15 years, is drinking coffee from a bottle she lifted to her lips, with a computerized arm that is wired into her brain. The connection, a plug in the top of her head, is called BrainGate, and it was developed by the Brown University neuroscientist John Donoghue and his team. What BrainGate and Cathy have done, along with similar feats by another paralyzed patient named Bob, are described in detached scientific prose in today’s issue of Nature. (Cathy is patient “S3″ and Bob is “T2.”)
But even dry language can’t hide this: These otherwise frozen people have an image of their arm and how it moves mapped onto a group of brain cells—that’s the phantom—and the device is able to read it. When Cathy thinks “grab,” the robot does what her real arm used to do.
When I first wrote about linking mind and machine several years ago for National Geographic, BrainGate got only a few sentences because it was facing some trouble. Matt Nagle, one of the earliest paralyzed patients in this study, had learned to move a cursor around a computer screen but then had his plug removed so he could take advantage of some therapy. (He subsequently passed away.) And Cyberkinetics Neurotechnology Systems, the private company Donoghue formed to supervise the clinical trial, went under in 2009. “It closed because of the 2008 financial crisis,” Donoghue says.
So another technology, helping amputees by connecting robotic arms to the severed nerves of their stumps, took center stage. I drank several cups of coffee with a woman named Amanda Kitts, who lifted a cup and angled it into her mouth just as if she were using her real arm. And in a sense she was: Her phantom limb still existed in her brain, and she just thought about natural movements and they happened.
At the Rehabilitation Institute of Chicago, which pioneered this work, scientists were able to conjure up the phantom on a computer screen, by attaching electrodes to Amanda’s stump to read the nerve signals. We watched the arm on the screen twist and grab, although Amanda’s flesh arm ended above her elbow.
But now “my hat is off to John Donoghue,” says Todd Kuiken, a physician and biomedical engineer at the institute who figured out how to link real nerves and artificial arms. “I let the brain and the nerves process these signals, and then I hijack them,” he says. By the time signals make it to the stump, they are refined and a lot of extraneous noise is removed naturally. “But John is reading activity directly from the brain, and extracting meaningful signals,” Kuiken says. “He’s right at the source.”
Indeed, the BrainGate plug is an array of 96 electrodes attached to the top of the skull and extending into the motor cortex, a brain region that controls body movements. “We’re focused on a little collection of cells, really just a few dozen neurons,” Donoghue says. A computer takes their electrical activity, finds signatures when Cathy and Bob are thinking “reach forward” and “bend the elbow,” and turns them into commands that move motors in the robot arm.
To make this happen after Cyberkinetics went under, Donoghue says, “we brought [the trial] back into the academic setting.” Brown University, Massachusetts General Hospital (an affiliate of Harvard Medical School), and Providence VA Hospital formed a collaboration, with Mass General administering the clinical trial. Stanford University recently joined the group. The academics, unlike the private company, found it easier to get financing from federal agencies.
And what they’ve been able to show is that paralyzed patients, after years of immobility, maintain a sophisticated phantom that can move in three dimensions, in the real world rather than just the flat two dimensions of a computer screen. BrainGate—a device inserted through the skull, tethering a patient to a computer with wires—is proof of feasibility, not therapy itself. (Kuiken’s arms, in contrast, have left the lab and gone home with dozens of patients.) But what BrainGate illuminates is a path along which the patients, through their phantoms, may be able to reach out in reality.
To learn more about Cathy’s journey along this path, you can read her biography, The Electric Mind, written by Jessica Benko and available today from The Atavist, an online publisher of short books, for iPads and Kindles.
[Photo credit: Braingate2.org]