Science fiction becomes reality with linking of man, machine
Posted on Wed, Aug. 04, 2004
_Science fiction becomes reality with linking of man, machineNEURAL ENGINEERING: Researchers rebuild a power company worker who lost his arms, giving him a robotic limb he controls with his mind.BY RONALD KOTULAKCHICAGO TRIBUNE
CHICAGO - Jesse Sullivan doesn't know exactly how his brain liberated itself from his armless body and began doing things for him on its own. But he has become a pioneer in a new field of medicine called neural engineering, whose practitioners are proving that there is such a thing as mind over matter.
Sullivan, a Tennessee power company worker who lost both arms in a job-related accident, has been outfitted by Rehabilitation Institute of Chicago researchers with a kind of bionic arm, which is controlled directly by his thoughts. This extraordinary achievement -- one of several breakthroughs nationally in linking mental activity with machines -- signifies an impending step of immense proportions: The human brain is poised to make its biggest evolutionary leap since the appearance of early man eons ago.
The first direct brain-computer hookups have been achieved in paralyzed patients with limited success. Building on that, Cyberkinetics, a Massachusetts biotech company, has government approval to implant chips containing 100 tiny electrodes into the brains of five quadriplegics this year to see if their thoughts can operate computers. At least two other research teams are planning similar brain-machine experiments in people.
"I think what we're going to find is that we can help people who are disabled become super-able in a new sense," said Timothy Surgenor, Cyberkinetics chief executive. "These people may be able to do things we can't do, like operate a computer faster or do very precise tasks. That's what we're really trying to accomplish. We're not trying to make an incremental change for these people. We're trying to do something that's a breakthrough."
These experiments have ushered science into the age of the cyborg, where the melding of brain and machine, long envisioned by the masters of science fiction, is possible. And the research is not just aimed at the disabled. Able-bodied people also may be able to expand the capacity of their minds.
"We're getting into sort of a scary field, in a way, that of cyborgs, where relatively healthy people are going to control machines" with their thoughts, said Dr. Philip Kennedy of Neural Signals Inc. in Atlanta. In 1998, Kennedy, a former Emory University neurologist, was the first researcher to implant an electrode into the brain of a totally paralyzed patient, who was then empowered to use his mind to slowly spell out words on a computer.
If it works the way Kennedy and many other scientists believe, the two-way brain-machine interface could give people expanded memory banks and calculating power. Implanted computer chips, for example, could enable people to quickly learn a foreign language and master other tough subjects.
The technology raises disturbing questions: Who would have access to electronic mind-enhancers? Would companies and other institutions coerce employees to have chips implanted in their brains to gain a competitive edge? Would chips be given to children? Would they be used to control the behavior of sex offenders and others? Would it change our notion of what it means to be human?
"How much can I do this and still be me?" asked Arthur Caplan, director of the University of Pennsylvania's Center for Bioethics. "Not every intervention threatens our sense of who we are, but if you really started to change your memory speed, or clearly started to be able to do things that you weren't able to do before, like learn languages in a day, or had infrared vision, you do start to get to questions about, 'Is that still me?'
"My answer to that is, I'm not sure. But that won't stop people."
The National Science Foundation essentially concluded, in a 2002 report called"Converging Technologies for Improving Human Performance," that "super people" are around the corner:
"At this unique moment in the history of technical achievement, improvement of human performance becomes possible. Better understanding of the human body and development of tools for direct human-machine interaction have opened completely new opportunities."
Sullivan, 57, of Dayton, Tenn., entered this dazzling world three years ago when his arms were incinerated on the job as a lineman for a Tennessee power company. He doesn't remember how it happened, but somehow he accidentally grabbed a high-tension wire carrying 7,400 volts of electricity. His arms took the full fury of the charge.
When it came time to rebuild Sullivan, doctors first fitted him with a standard plastic-and-metal prosthesis. But it moved clumsily and demanded arduous shoulder gyrations.
That's the way things stood until last year, when Sullivan happened to be in the right place at the right time. That was Rehabilitation Institute of Chicago, where Dr. Todd Kuiken, director of amputee services, was getting ready to test a 20-year-old dream, an experimental myoelectric arm, a device intended to transmit instructions from the brain via unused nerves to points outside the body. In short, Sullivan was to think the arm to move.
Sullivan had one important thing in his favor: The memory of his arms and hands remained fresh in his mind, while the neural circuits that controlled those parts were still powered up as they had been before the accident. Would the impulses that commanded movement in his missing left arm leap from his brain, travel down his functional but destination-less nerves to the computerized artificial arm and bring it to life?
Sullivan remembers the moment well. It was a January day in Chicago, but Sullivan's thoughts were on matters far from the frigid weather outside. A single mantra kept running through his mind as he concentrated on getting plastic and metal to react solely to his will: "Think, Jesse, think."
Then it happened. Something moved.
"That was probably one of the best feelings I'd had since I had my accident, when they first put it on and told me to close my hand," Sullivan said. "When I did, this thing closed. This grasper on the end of the arm closed up."
Sullivan's robotic arm has given him a new sense of independence. He can do things he couldn't a year ago, such as shave, put on socks, weed the garden, water the yard, open small jars, use a pair of scissors and throw a ball to his grandson.
"It gave me part of my dignity back," he said.
Sullivan doesn't have to think hard anymore about doing something; he simply does it the way he always did. "I feel my hand when I want to pick something up, then I just close my hand," he said. When he wants to grab a bottle of water, for instance, the computerized arm moves forward, the elbow bends and the mechanical hand grasps the bottle, bringing it to his lips, as his natural arm once did.
It feels so natural, in fact, that Sullivan forgot himself this summer and yanked off the mechanical hand trying to start a lawn mower. The arm had to be sent back to the Rehabilitation Institute for repairs.
Human Brain to Machine Interface May Now Be Feasible
Human Brain to Machine Interface May Now Be Feasible
Laurie Barclay, MD
May 6, 2004 — Directly using human brain neuronal activity to operate external neuroprostheses may now be feasible, according to a presentation on May 4 at the 72nd annual meeting of the American Association of Neurological Surgeons held in Orlando, Florida. This work could potentially benefit patients with quadriplegia or other focal neurological injury who are unable to use their extremities because of a breakdown in connectivity between their limbs and brain motor centers.
"For all kinds of motor training, such as riding a bicycle, people incorporate an external device into their schema, and the process becomes subconscious," senior author Dennis Turner, MD, MA, a neurosurgeon at Duke University in Durham, North Carolina, told Medscape. "We will build on that phenomenon in our human studies."
Earlier studies revealed that monkeys could use brain signals from hundreds of neurons chronically implanted with high-density microelectrode arrays to control a neuroprosthetic robotic arm.
In this study, 11 volunteer patients with Parkinson's disease had ensemble recordings of neuronal activity from a novel 32-channel electrode array implanted in the subthalamic nucleus and thalamic motor regions during surgical placement of deep brain stimulators. There were no intraoperative complications.
At the same time, the patients played a hand-controlled video game for up to 10 minutes, in which they were placed in a semi-sitting position before a video screen and instructed to adjust their hand-gripping force on a squeeze ball to reach a target level of force as quickly as possible. Shoulder and arm contractions were prevented by positioning the limb on an armboard so that the only motion tested was the patient's gripping force generated by the hand.
During 23 recording sessions, the investigators simultaneously recorded up to 55 neurons. After optimal training, synchronously recorded neuronal activity predicted motor activity (r = 0.64; r2 = 0.68). Larger neuronal ensembles produced more accurate motor predictions, with 61% of neurons from the subthalamic nucleus and 81% of neurons from thalamic motor areas varying with gripping force.
These recorded signals contained sufficient information to reliably predict hand motions, and therefore to accurately control an external robotic prosthesis. This was especially encouraging because there were only about five minutes of data per patient, which included about one or two minutes to train the patient to perform the task. As clinical testing progresses and electrode arrays are implanted for a long period of time, it would be easier to achieve a workable control system for external devices, according to the authors.
Unlike the monkey studies, in which recording was from the cortical surface, the human studies used recording from subcortical structures. Although both locations may provide viable options for sampling neuronal information to control a prosthetic device, subcortical electrodes offer certain advantages. The subcortical areas are denser, with more cells to record from in a smaller area; they filter all the signals for motor control before they reach the final cortical output; and they are deeper, so electrodes implanted there are more stable than cortical electrodes.
In addition to a neuroprosthetic hand, potential applications of this technique include a neurally controlled wheelchair or keyboard, or even a speech synthesizer for patients with stroke or amyotrophic lateral sclerosis.
"Patients who don't have use of their arm still show in MRI studies that the control centers in the brain are working normally [and become active] when they are asked to imagine moving their arm," Dr. Turner says. "We have good hope that the neurons in those centers can still provide the same signals, even though the arm isn't physically working."
Although the investigators have applied for approval to begin implanting experimental electrode arrays for long-term use in quadriplegic patients, they caution that many years of development and clinical testing must ensue before any neuroprosthetic devices are clinically available.
This work is in press in the July 2004 issue of Neurosurgery. The Defense Advanced Research Projects Agency and the National Institutes of Health supported this study.
AANS 72nd Annual Meeting: Abstract 825. Presented May 4, 2004.
Reviewed by Gary D. Vogin, MD