PROVIDENCE, R.I.— John Donoghue believes there may be a solution to spinal cord injuries that doesn’t require a move into the controversial world of stem cell research.
The Brown University neuroscience professor believes computers and wiring may be able to stand in for the body’s own circuits, linking brain to muscles and bypassing the injury.
“We’re replacing the biological wires with physical ones,” he said.
The BrainGate Neural Interface system, a brain-computer linkup developed first in Donoghue’s lab at Brown and refined at Cyberkinetics, a Foxboro, Mass., company he founded, has been implanted in Matthew Nagle, who was paralyzed by a knife wound to the neck in 2001.
For about nine months, Nagle, who cannot move his legs or arms, has been able to control a computer cursor using only his thoughts. With it, Nagle can control a television, open messages in a mock e-mail program and play simple video games.
Donoghue says the technology, which is years away from being fully developed, could someday help people like Nagle to live more independently or hold jobs by connecting their brains with computers, robotic devices or even their paralyzed limbs.
The tiny device that allows Nagle to manipulate the cursor is implanted on the surface of his brain, at the site on his primary Motor cortex dedicated to arm movement.
When Nagle thinks about moving his hand to the right, the impulses are captured by the sensor, which transmits them to computers, which in turn, translate them into a direction to move the cursor to the right on a computer screen. Nagle has enough control to draw a wobbly circle.
His control isn’t nearly as good as if he had his hand on a computer mouse, but Donoghue said the very fact that Nagle can manipulate the computer by thinking about it answered some important questions.
Because Nagle’s spinal cord was damaged and his brain has been cut off for a few years from the muscles it would normally control, scientists weren’t sure whether his brain could still generate the impulses that were once needed to move his arms. Nagle’s implant showed it does.
“We didn’t really know that just by thinking he could modulate the (neural) activity,” Donoghue said, adding that while it’s previously been shown monkeys can play video games using only their minds, their nervous systems were uninjured.
The development means scientists might one day be able to connect the brains of paralyzed patients to muscle stimulators, allowing them to once again move their paralyzed limbs. Donoghue envisions a time in the future when people with spinal cord injuries or disease that attack the nerves will move like others, with wiring under their skin replacing their own nervous system.
Walking might be a challenge to restore, because it requires a complex combination of muscle interaction and balance, but Donoghue thinks the technology can be used to restore to patients many of the activities a healthy person can perform. For example, patients could one day use the technology to operate robotic arms or to power an electric wheelchair.
“Eventually, we would like to hook (Nagle) up to a physical device that can do things for him, or to his own muscles,” Donoghue said.
Currently, the BrainGate device is in the first of two required federal Food and Drug Administration trials on humans. The researchers are looking for four more people to test the device for the first round of trials.
Donoghue is working on making the implant wireless so that the patient won’t have to be physically connected to a computer console, and automating the system so it doesn’t need to be calibrated each time it’s used.
Another challenge is refining how the brain’s signals are translated into on-screen motion so patients have more precise control. The translation process involves complex algorithms that transform the language of firing neurons into commands that control the computer.
Donoghue’s approach has its critics, with some arguing there was no reason to use an invasive, surgical technique with a patient like Nagle, who can operate some devices using the limited muscle movements he retains. They argue that BrainGate might only make sense for a completely “locked in” patient who couldn’t move at all.
Even for severely limited patients, alternatives exist, such as computers controlled using eye movement.
But Donoghue says technologies such as sensors that track eye motion have drawbacks because they take up a person’s attention.
“You can’t carry on everyday activity” while using them, he said, noting that while Nagle is manipulating the computer cursor with the motor cortex of his brain, he can also carry on a conversation.
Other technologies, he said, are “a substitute or a surrogate for the function you want,” he said, whereas BrainGate uses the appropriate part of the brain for the task.
By ELIZABETH ZUCKERMAN – Associated Press Writer