Two patients in the United States who are paralysed from the neck down
have been able tocontrol a robotic arm using their thoughts.
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It allowed one to drink unaided for the first time in nearly 15 years.
The technique, described in the journal Nature, links a sensor
implanted in the brain to a computer, which translates electrical
signals into commands.
In years to come, scientists want to reconnect the brain to paralysed
limbs to enable them tofunction again.
The project was a partnership by Brown University and the Department
of Veteran Affairs, Rhode Island, and the Departmentof Neurology at
Massachusetts General Hospital and Harvard Medical School, Boston.
In 2006 in a previous Nature paper , the team showed that the same
neural interface system could be used by a paralysed patient to
control a cursor on a computer screen.
I couldn't believe my eyes when I was able to drink coffee without
help. I was ecstatic. I had feelings of hope and a great sense of
independence"
Cathy Hutchinson
Study patient
The key is a tiny sensor implantedon to the surface of the motor cortex.
'True happiness'
Thinking about moving an arm orhand activates neurons in this part of
the brain and the electricalactivity is sent via a cable to a
computer, which translates them into commands.
Both patients in this latest research project were paralysed many
years ago by strokes and have no viable movement below the neck.
Video footage shows 58-year-old Cathy Hutchinson using the
neuralinterface to control a robotic arm and bring a flask of coffee
to her mouth. It was the first time in nearly 15 years that she had
taken a drink unaided.
She communicates by picking out letters on a board using eye movement
and wrote: "I couldn't believe my eyes when I was able to drink coffee
without help. I was ecstatic. I had feelings of hope and a great sense
of independence."
That was echoed by Prof John Donoghue, a neurologist at Brown University.
He said: "There was a moment of true joy, true happiness. It was
beyond the fact that it was an accomplishment. I think it was an
important advance in the field of brain-computer interfaces that we
had helped someone do something they had wished to dofor many years."
Practical use
This research shows that the part of the brain that deals with
movement continues to function more than a decade after paralysis.
The sensor is implanted in the patient's brain and linked to a computer
Furthermore, the chip continues to function long-term - Cathy
Hutchinson had the sensor fitted six years earlier.
The technology is years away from practical use and the trial
participants used the system under controlled conditions in their
homes with a technician on hand.
Nonetheless, another of the report authors, Prof Leigh Hochberg, said
the team had four goals:
To develop effective communications systems for people with locked-in
syndrome, giving them control over a cursoron a computer screen
To create improved neural control of robotic-assistive devices for
patients with paralysis
To use the system to allow amputees to control a prosthetic limb by
the neural interface
To enable paralysed patients to reconnect their brain to their limbs
using this system so that they could use their own hand to pick up a
coffee cup.
Prof Hochberg freely admitted that the third and fourth goals were
distant ambitions but they were the "real dream" for people with such
disabilities. The researchers say it is impossible toput a timescale
on when this might be achieved.
Story Landis, director of the National Institute of Neurological
Disorders and Stroke, which part-funded the work, said: "This
technology was made possible bydecades of investment and research into
how the brain controls movement.
"It's been thrilling to see the technology evolve from studies of
basic neurophysiology and move into clinical trials, where it is
showing significant promise for people with brain injuries
anddisorders."
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