1. Can't this most easily be explained by invoking hierarchical PCT?
2. Is there any other theory of motor behavior than can explain it at all?
I'll try to find the Nature report ASAP.
Best regards,
Ted
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May 17, 2012
<http://www.huffingtonpost.com/healthy-living/>
<http://www.huffingtonpost.com/healthy-living/>
Edition: U.S.
Paralyzed Woman Controls Robot Arm Using Only Her Mind
By MALCOLM RITTER 05/16/12 02:17 PM ET
Cathy Hutchinson of East Taunton, Mass. sips a drink held by a robotic arm
during a test at a long-term care residence for adults with neurological
disease in Dorchester, Mass. A report by researchers published in the
Thursday, May 17, 2012 issue of the journal Nature describes how two people,
paralyzed years before by strokes, were able to control free-standing
robotic arms with the help of a tiny sensor planted in their brains.
NEW YORK -- Using only her thoughts, a Massachusetts woman paralyzed for 15
years directed a robotic arm to pick up a bottle of coffee and bring it to
her lips, researchers report in the latest advance in harnessing brain waves
to help disabled people.
In the past year, similar stories have included a quadriplegic man in
Pennsylvania who made a robotic arm give a high-five and stroke his
girlfriend's hand, and a partially paralyzed man who remotely controlled a
small robot that scooted around in a Swiss lab.
It's startling stuff. But will the experimental brain-controlled technology
ever help paralyzed people in everyday life?
Experts in the technology and in rehabilitation medicine say they are
optimistic that it will, once technology improves and the cost comes down.
The latest report, which was published online Wednesday in the journal
Nature, comes from scientists at Brown University, the Providence VA Medical
Center in Rhode Island, Harvard Medical School and elsewhere.
It describes how two people who lost use of their arms and legs because of
strokes years before were able to control free-standing robotic arms with
the help of a tiny sensor implanted in their brains.
The sensor, about the size of a baby aspirin, eavesdropped on the electrical
activity of a few dozen brain cells as the study participants imagined
moving their arms. The chip then sent signals to a computer, which
translated them into commands to the robotic arms.
The computer was taught how to interpret the brain patterns through practice
as the paralyzed participants watched the robot arms move and then imagined
that they were moving their own arms the same way.[Emphasis mine -- Ted]
In one task to test the system, the two participants tried to direct a robot
arm to reach out and squeeze foam balls in front of them. The man succeeded
in less than half his attempts, but the woman was able to do it about 60
percent of the time.
The woman, Cathy Hutchinson of East Taunton, Mass., was also asked to use
the arm to drink the coffee. That involved picking up the bottle, bringing
it to her lips so she could sip from a straw, and putting the bottle back on
the table. She succeeded in four out of six tries with the arm, which was
specially programmed for this task.
"The smile on her face ... was just a wonderful thing to see," said Dr.
Leigh Hochberg, a researcher with the Providence VA, Brown and Massachusetts
General Hospital.
Researchers said in Hutchinson's case that the results show that the
implanted chip still worked after five years, and that her brain was still
generating useful signals even though she hadn't moved her arms in almost 15
years.
The ultimate goal, researchers said, is an implanted device that would
reactivate a person's own paralyzed limbs. Another goal is to operate
high-tech prostheses for amputees.
Andrew Schwartz, who is doing similar research at the University of
Pittsburgh, said the coffee-sipping was encouraging because it represents an
everyday task a paralyzed person might want to do. "I think it's showing
this technology has therapeutic potential," he said.
"The field is rapidly advancing, and I think this offers hope for people who
are paralyzed," Schwartz said. "The types of movements we'll be able to do
are getting more and more sophisticated at a rapid pace."
But he and others said the technology faces a number of hurdles to
widespread use, like reducing its high cost, making it more reliable, and
refining the technology. For example, the brain implant now sends signals
out with a wire through the skull, and researchers want to develop a
completely implanted version that communicates wirelessly.
Another step toward wide use will be enticing companies to invest the money
to make commercial products. Just when that might happen is an open
question, Schwartz said, but it could be in the next couple of years, with
prostheses or free-standing robotic arms on the market a few years after
that.
Dr. Bruce Gans, executive vice president and chief medical officer of the
Kessler Institute for Rehabilitation in West Orange, N.J., said the
technology is too expensive now for widespread use. But if brain control
finds uses outside the relatively limited market of paralyzed people, that
might drive improvements in technology and dramatically reduce the cost, he
said.
Gans suggested other uses might involve industrial applications;
neuroscientist Andrew Jackson of Newcastle University in England suggested
it might be in rehabilitation for victims of less severe strokes.
At some point, Gans said, "It may even turn into something that allows a
person with paralysis to go back to work, so it becomes a tool a vocational
rehabilitation program could eventually endorse and support."
Dr. Preeti Raghavan, an expert in physical rehabilitation of the arms and
hands at the New York University Langone Medical Center, noted that the cost
of the technology would be weighed against the significant expense of
caregiving for paralyzed people who can't do much on their own.
She said she expected that within a decade, many people may be using the
technology to control their own limbs or robotic arms. Gans said that wider
use of robotic arms might be feasible within five years, but that
reactivating paralyzed limbs could be decades away.
Science is the process of eliminating supernatural explanations. - Robert
Park