With a tiny electronic chip implanted in his motor cortex, a man paralyzed for five years from the neck down has learned to use his thoughts to operate a computer, turn on a TV set, open e-mail, play a video game and manipulate a robotic arm.
Though the movements are still rudimentary, they represent the first successful steps toward using the mind to directly control machines, according to the lead article in Wednesday’s issue of the British scientific journal Nature.
Researchers reported that the paralyzed man, a 25-year-old Massachusetts resident, and a patient at the Rehabilitation Institute of Chicago have become so nimble with their mind-over-matter movements that they are able to carry out computer functions while talking, much as a normal person can interact with people while working at a keyboard.
A third quadriplegic patient, also from Massachusetts, who is unable to speak as a result of a stroke that destroyed her brain stem, has been able to use her thoughts to type messages using specialized software.
As the technology advances, the goal is for paralyzed people to use their muscles again, perhaps even walk, by allowing brain signals to bypass damaged spinal cords and operate lifeless limbs.
“This is a proof of concept that you can get signals out of the brain that can provide useful controls,” said senior author John Donoghue, director of Brown University’s Brain Science Program. “I see this as opening the door to a whole new kind of neurotechnology that will provide new opportunities for those who have paralysis or other movement disorders.”
The chip implanted in the patients is about the size of a baby aspirin and contains 100 electrodes, each thinner than a human hair, that pick up the electronic chatter from 30 to 60 neurons in the motor cortex, which normally controls arm movement.
When the patient imagines moving his arm, it activates the neurons. The chip converts this activity into a program for controlling a computer cursor, TV, e-mail and other devices.
The first patient to receive the chip was Matthew Nagle of Massachusetts, whose spinal cord was severed in 2001 by a stab wound in his neck. The experiment was “an incredible journey,” he said in a statement. “No one knew whether this would work with humans or how long it would take to master. After the first couple days, I was able to move a computer mouse, just by thinking. That was very impressive. And then we went on from there: I could turn on the TV, open and close lights and move a mechanical hand.”
The device, called the BrainGate Neural Interface System, is produced by Cyberkinetics of Foxborough, Mass., which was established by Donoghue and others.
Of the four patients given the brain chip, three are paralyzed from spinal cord injury or brain stem stroke, and one has amyotrophic lateral sclerosis, better known as Lou Gehrig’s disease. The FDA has authorized the recruitment of two more spinal cord injury patients and four more ALS patients.
Stronger brain cells
Experiments with monkeys showed that brain cells interacting with the chip become stronger with use, said University of Chicago neuroscientist Nicholas Hatsopoulos, who participated in the development of BrainGate while at Brown and is a co-founder of Cyberkinetics.
“Animal studies show that the motor cortex does adapt as the animal learns something new,” he said. “It’s like learning to use a tennis racket until it becomes an extension of your own arm.”
Will healthy people ever be able to use a brain chip to enhance their memory, strength, vision or other functions? Hatsopoulos says that’s still science fiction. Such a procedure, he added, would raise ethical issues because surgery is required to implant the device.
“But imagine a memory chip containing the Encyclopedia Britannica that would interact with your brain and you could access it,” he said. “That’s totally far out.”
The first brain-computer interface experiment in humans was conducted by Philip Kennedy of Georgia State University in 2000. Only one or two electrodes were used to pick up activity from a similar number of individual neurons in a paralyzed female.
By detecting the activity of many neurons at the same time, the Brown University device is more adept at detecting normal brain talk and converting it into more sophisticated controls.
The results of the study are preliminary but promising, neuroscientist Stephen Scott of Queen’s University in Kingston, Ontario, Canada wrote in a viewpoint article in Nature. Some scientists had thought the motor cortex would lose function from disuse after years of paralysis, but the Brown experiment showed these neurons were still viable, Scott said.
The research team still faces daunting problems of equipment reliability. Nagle’s device worked for about a year after it was implanted in 2004 but was removed when it began to fail.
BrainGate is “still far from being a useful device that actually increases the quality of life,” said Andrew Schwartz, a University of Pittsburgh neuroscientist who was not involved in the study but who conducts research on brain-computer interactions.
Donoghue said a new generation of technology is under development that would get rid of bulky equipment and wiring attached to a patient’s head in favor of a wireless communication system that would be more suitable for operating a TV or wheelchair.
Chicago patient involved
Dr. David Chen, director of the Rehabilitation Institute of Chicago’s spinal cord injury program, has been working with a 55-year-old patient who was paralyzed from a fall eight years ago. The man has shown a higher level of brain-chip response than Nagle and is expected to develop a greater degree of mind control, Chen said.
“We’re quite a ways away from developing treatments to repair spinal cord injuries,” Chen said. “This is one of those technologies that we felt has the potential to have a much more immediate application in terms of how it may impact on a person’s life.”
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rkotulak@tribune.com
