High-tech device gives hope for a better life

Electronic chips implanted in paralyzed patients help them use their minds to perform everyday tasks


CHICAGO -- With a tiny, electronic chip implanted in the motor cortex of his brain, a 25-year-old man paralyzed from the neck down for five years 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 - the first successful steps toward using the mind to directly control machines.

Two subsequent patients with the implanted brain chips - one at the Rehabilitation Institute of Chicago - have advanced their brain-computer interface skills even further, although all movements are still rudimentary. One, a Massachusetts quadriplegic unable to speak as a result of a stroke that destroyed her brain stem, uses her thoughts to type messages using specialized software.

So nimble has their mind-over-matter movements become that the two patients who were able to speak could carry out their computer functions while talking at the same time, much as a normal person interacts with computers and people, according to the lead article in yesterday's issue of the British scientific journal Nature.

"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."

So far, four patients have been implanted with the brain chip. Three were paralyzed from spinal cord injury or brain stem stroke, and one has amyotrophic lateral sclerosis, better known as ALS or Lou Gehrig's disease. The FDA has authorized the recruitment of two more spinal cord injury patients and four more ALS patients.

The chip that's implanted in their brains is about the size of a baby aspirin. It has 100 electrodes, each thinner than a human hair, that pick up the electronic chatter from between 30 to 60 neurons in the motor cortex, which normally controls arm movement.

The device, called the BrainGate Neural Interface System, is produced by Cyberkinetics of Foxborough, Mass., which was established by Donoghue and others.

The patient imagines moving his arm to activate the neurons. The chip registers this activity, which is then converted into a program for controlling a computer cursor, TV, e-mail and other devices, and patients quickly learn how to adjust their thought processes to control the different systems. It only takes minutes, for example, for a patient to imagine moving his arm to track a moving cursor on a computer screen, and then to be able to move the cursor with his own thoughts.

Experiments with monkeys showed that the 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 normally healthy people ever be able to use a brain chip to enhance their memory, strength, vision or other functions? Hatsopoulos says that's more science fiction right now and would raise ethical issues because the procedure involves surgery to implant the device on the brain.

"But imagine a memory chip containing the Encyclopedia Britannica that would interact with your brain and you could access it. That's totally far out," he said.

The first brain-computer interface experiment in humans was conducted with limited results in 2000 by Philip Kennedy of Georgia State University. Only one or two electrodes were used in a paralyzed female patient. They picked up activity from a similar number of individual neurons.

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.

Although the results of the study are preliminary and more research needs to be conducted, they are promising, neuroscientist Stephen H. Scott of Queen's University, Kingston, Ontario, wrote in a News and Views article in the same Nature issue. "This research suggests that implanted prosthetics are a viable approach for assisting severely impaired individuals to communicate and interact with the environment."

While some scientists believed the motor cortex would lose function from disuse after years of paralysis, Scott said the Brown experiment showed for the first time that these neurons were still viable.

Nevertheless, the research team still faces daunting problems of equipment reliability. The first patient, Matthew Nagle, a Massachusetts man whose spinal cord was severed by a neck stab wound in 2001, received the first brain implant in 2004. The device worked for about a year but then began to fail, and it was removed.

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