Paralyzed man moves computer cursor through thought

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Brain sensor allows mind-control

Mr Nagle was the first patient to trial the device
A sensor implanted in a paralysed man's brain has enabled him to control objects by using his thoughts alone.
The experimental set-up allowed the man, who has no limb movement at all, to open e-mail, play a computer game, and pinch a prosthetic hand's fingers.

The US team behind the sensor hopes its technology can one day be incorporated into the body to restore the movement of paralysed limbs themselves.

The Massachusetts-based team's study is published in the journal Nature.

It's just wild

Matthew Nagle

Matthew Nagle, 25 at the time of the trial, was left paralysed from the neck down and confined to a wheelchair after a knife attack in 2001. He was the first patient to try out the brain sensor.

A team of scientists inserted the device, called a neuromotor prosthesis (NMP), into an area of the brain known as the motor cortex, which is responsible for voluntary movement.

The NMP comprises an internal sensor that detects brain cell activity, and external processors that convert the activity into signals that can be recognised by a computer.


See how the system works

Although the patient's spinal cord had been severed for three years by the time of the trial, the scientists found that brain cell activity - or neural firing patterns - persisted in the patient's motor cortex.

The electrodes in the NMP were able to record this activity and send it to a computer. The computer then translated the firing patterns into movement commands which could drive computer controls or artificial limbs.

Regained independence

Using the device, Mr Nagle was able to move a computer cursor to open an e-mail, play simple computer games, open and close a prosthetic hand, and use a robot limb to grasp and move objects.

Mr Nagle said the sensor had restored some of his independence by allowing him to carry out a number of tasks - such as turning the lights on - that a nurse would normally do for him.

He told the BBC: "I can't put it into words. It's just wild."

Lead researcher Dr Leigh Hochberg, a neurologist at the Massachusetts General Hospital, said: "One of the exciting results from the trial is that this part of the brain, the motor cortex, could still be activated voluntarily by this gentleman with spinal cord injury.

"The fact that this activity was still there, despite the injury that had occurred several years ago, is very encouraging for our potential ability to harness those signals to control an external device."

Co-author Professor John Donoghue is director of the brain science programme at Brown University and chief scientific officer of Cyberkinetics, the company that created and trialled the sensor.

He said: "The results hold promise to one day being able to activate limb muscles with these brain signals, effectively restoring brain-to-muscle control via a physical nervous system."

The sensor is inserted directly into the brain
The team also looked at a second, 55-year-old patient, but said technical issues meant the sensor could not record brain activity.

Professor Stephen Scott, from Queen's University, Ontario, Canada, said in a related article: "This research suggests that implanted prosthetics are a viable approach for assisting severely impaired individuals to communicate and interact with the environment."

But he warned that considerable problems needed to be overcome before this technology could be put into regular use.

He said problems such as the device's longevity, infection risks, and data transfer methods needed to be looked at.

Tested too early?

Professor Igor Aleksander, an expert in neural systems engineering at Imperial College London, UK, said: "I think this is enormously important stuff because there is real potential for helping people that have had severe neural disabilities."

But Professor Miguel Nicolelis, a neurobiologist from Duke University, was critical of the research.

He told the BBC's Science in Action programme that although some positive signs had been seen for one patient, the paper showed that the technology did not work in the second, older patient.

He said: "When you decide, like this company did, to go into clinical trials for an invasive technique the stakes are very high.

"They should have demonstrated something that lasts for a long period of time, that it is reliable and safe, and that it can restore much more elaborate functions. I don't think that this paper shows that.

"I think it was too early to use this kind of technology in this kind of clinical trial."

Matthew Nagle's story was featured in a BBC Radio 4 Frontiers programme last year. Wednesday's announcement represents the formal publication of the research in a scientific journal.

According to Health Day News report of Steven Reinberg dated July 12,2006 wednesdsay:In the first such experiment in humans, researchers say a quadriplegic patient with spinal cord injury produced brain signals that allowed him to shift a cursor on a computer screen.

Using signals picked up by a sensor implanted in his brain that were then translated into electronic impulses, the 25-year-old man was able to control a computer cursor that allowed him to manipulate mechanical devices.

Successful use of this "brain-computer interface device" is being hailed as an important breakthrough for those paralyzed by injury or disease.

"One of the most exciting findings is that one part of the brain -- the motor cortex that usually sends its signals down through the spinal cord to control movement -- can still be used by this patient to control an external device, even after the spinal cord injury," said lead researcher Dr. Leigh Hochberg, a neurologist at Massachusetts General Hospital.

The study utilized a new brain-computer interface device called the BrainGate Neural Interface System. It's in the early stages of clinical testing, Hochberg said.

His team reports the findings in the July 13 issue of Nature.

The patient under study is a 25-year-old man who suffered a knife wound in 2001 that cut his spinal cord at the neck, leaving his arms and legs paralyzed.

In the trial, the patient underwent 57 sessions over nine months, during which time the implanted BrainGate sensor recorded activity in his motor cortex while the man imagined moving his paralyzed limbs. He then used that "imagined motion" in several computer-based tasks.

Within little or no learning time, the patient began to be able to move a computer cursor via the device to open simulated e-mail, draw circular shapes and play simple video games. He also was able to open and close a prosthetic hand and use a robotic limb to grasp and move objects, the researchers said.

The findings may have implications for paralyzed patients everywhere. "In the short run, it may be possible for someone who can't use their arms or legs to regain control over their environment," Hochberg said. "In the long-run, using additional stimulation technology, they may be able to regain control over their own limbs," he added.

Hochberg see this as an important first step in helping paralyzed patients regain some control over their lives.

"This study suggests that the signals in the motor cortex are not only still there, but they can be modulated voluntarily to do things that are similar to what those cells were doing before," Hochberg said. "So, it is possible that someone who can't use their arms might be able to use the same cell in the motor cortex through a device like this to control a cursor on a computer screen and therefore improve their ability to control their environment."

Bijan Pesaran, an assistant professor of neural science at New York University's Center for Neural Science, called the finding "an exciting advance in the field of neural prostheses. For the first time, they show that the motor cortex of paralyzed human patients is still active years after a spinal cord injury."

"By simply imagining movements, their patient can use signals in the motor cortex to achieve effective prosthetic control. The next step will be to compare the performance and longevity of this device with other devices that use different signals and different brain areas involved in movement planning," Pesaran added.

In another study reported in the same issue of the journal, researchers at Stanford University say they've found a faster method of processing signals from the brain. The new technology could improve devices such as BrainGate.

"We found that it is possible to select targets, for example, keys on a keyboard, much more rapidly than previously believed," said senior author Krishna Shenoy, an assistant professor of electrical engineering and neuroscience.

The importance of the finding is that it will make it easier for patients to regain some independence, Shenoy said.

In their experiments, Shenoy's team worked with rhesus macaque monkeys. By identifying the brain waves the monkeys generated when they were only thinking about moving an arm, the researchers were able to find the optimum point for both speed and accuracy for the direction of the movement. This was then used to create a computer algorithm that can be used in neuro-prosthetic devices.

"We are really talking about a day where we can build interfaces with the brain," Shenoy said. "If it is a spinal cord injury, we can bypass it. If you're blind, we could write visual images into areas of the brain," he explained.

The difference in treating spinal cord injuries with stem cells or with a neuroprosthetic is that stem cells have the potential for a cure, Shenoy said. "What we are talking about isn't a cure, it's a remediation, it's a bypass," he said.

In a News and Views article in the same issue of Nature, one expert surveyed recent progress in neuroprosthetics.

Stephen H. Scott, from the Centre for Neuroscience Studies at Queens University, Kingston, Ontario, Canada, said these devices will probably do more than just help patients communicate. They may also help them regain control of important bodily processes such as bladder function, he said.

Whether this technology can actually help someone regain their ability to walk is more doubtful, Scott said.

"Are they going to be able to run an electric wheelchair? I think they could do that. It's possible they could drive a car. Getting them to walk is harder," he said.

According to another report from LONDON: A Paralyzed man using a new brain sensor has been able to move a computer cursor, open e-mail and control a robotic device simply by thinking about doing it, a team of scientists said on Wednesday.

They believe the BrainGate sensor, which involves implanting electrodes in the brain, could offer new hope to people Paralyzed by injuries or illnesses.

"This is the first step in an ongoing clinical trial of a device that is encouraging for its potential to help people with paralysis," Dr Leigh Hochberg, of Massachusetts General Hospital, said in an interview.

The 25-year-old man who suffered paralysis of all four limbs three years earlier completed tasks such moving a cursor on a screen and controlling a robotic arm.

He is the first of four patients with spinal cord injuries, muscular dystrophy, stroke or motor neurone disease testing the brain-to-movement system developed by Cyberkinetics Neurotechnology Systems Inc in Massachusetts.

"This is the dawn of major neurotechnology where the ability to take signals out of the brain has taken a big step forward. We have the ability to put signals into the brain but getting signals out is a real challenge. I think this represents a landmark event," said Professor John Donoghue of Brown University in Rhode Island and the chief scientific officer of Cyberkinetics.

The scientists implanted a tiny silicon chip with 100 electrodes into an area of the brain responsible for movement. The activity of the cells was recorded and sent to a computer which translated the commands and enabled the patient to move and control the external device.

"This part of the brain, the motor cortex, which usually sends its signals down the spinal cord and out to the limbs to control movement, can still be used by this participant to control an external device, even after years had gone by since his spinal cord injury," added Hochberg, a co-author of the study published in the journal Nature.

Although it is not the first time brain activity has been used to control a cursor, Stephen Scott of Queen's University in Ontario, Canada said it advances the technology.

"This research suggests that implanted prosthetics are a viable approach for assisting severely impaired individuals to communicate and interact with the environment," he said in a commentary in the journal.

In a separate study, researchers from Stanford University Schools of Medicine and Engineering described a faster way to process signals from the brain to control a computer or prosthetic device.

"Our research is starting to show that, from a performance perspective, this type of prosthetic system is clinically viable," Stephen Ryu, an assistant professor of neurosurgery at Stanford, said in a statement.



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