* Paralysed woman controls robotic arm with thought
* Brain-machine interface research moving fast
* Technology could re-awaken unresponsive muscles
* Difficult ethical questions
By Chris Wickham
LONDON, Dec 17 (Reuters) – Researchers in the United States
have developed a robotic arm controlled directly by thought with
a level of agility closer than ever to a normal human limb.
Jan Scheuermann, a 52 year-old woman who was diagnosed with
a degenerative brain disorder 13 years ago and is paralysed from
the neck down, was able operate the robotic arm with a level of
control and fluidity not seen before in this type of advanced
prosthesis.
Experts are calling it a remarkable step forward for
prosthetics controlled directly by the brain. Other systems have
already allowed paralysed patients to type or write in freehand
simply by thinking about the letters they want.
And in the last month, researchers in Switzerland used
electrodes implanted directly on the retina to enable a blind
patient to read.
The development of brain-machine interfaces is moving
quickly and scientists predict the technology could eventually
be used to bypass nerve damage and re-awaken a person’s own
paralysed muscles.
In the meantime, they say, systems like this could be paired
with robotic ‘exoskeletons’ that allow paraplegics and
quadraplegics to walk.
COMPLEX ALGORITHM
In the latest study, published in the Lancet, a research
team from the University of Pittsburgh Medical Center implanted
two microelectrode devices into the woman’s left motor cortex,
the part of the brain that initiates movement.
The medics used a real-time brain scanning technique called
functional magnetic resonance imaging to find the exact part of
the brain that lit up after the patient was asked to think about
moving her now unresponsive arms.
The electrodes were connected to the robotic hand via a
computer running a complex algorithm to translate the signals
that mimics the way an unimpaired brain controls healthy limbs.
“These electrodes are remarkable devices in that they are
very small,” Michael Boninger, who worked on the study, told
Reuters. “You can’t buy them in Radio Shack.”
But Boninger said the way the algorithm operates is the main
advance. Accurately translating brain signals has been one of
the biggest challenges in mind-controlled prosthetics.
“There is no limit now to decoding human motion,” he said.
“It gets more complex when you work on parts like the hand, but
I think that, once you can tap into desired motion in the brain,
then how that motion is effected has a wide range of
possibilities.”
It took weeks of training for Scheuermann to master control
of the hand, but she was able to move it after two days, and
over time she completed tasks – such as picking up objects,
orientating them, and moving them to a target position – with a
91.6 percent success rate. Her speed increased with practice.
The researchers plan to incorporate wireless technology to
remove the need for a wired connection between the patient’s
head and the prosthesis.
They also believe a sensory loop could be added that gives
feedback to the brain, allowing the user to tell the difference
between hot and cold, or smooth and rough surfaces.
“This bioinspired brain-machine interface is a remarkable
technological and biomedical achievement,” said Gr (c)goire
Courtine at the Swiss Federal Institute of Technology in
Lausanne, who was not involved in the study.
“Though plenty of challenges lie ahead, these sorts of
systems are rapidly approaching the point of clinical fruition,”
Courtine said in a comment piece in the Lancet linked to the
study.
ETHICAL QUESTIONS
Although using technology to restore movement, sight or
hearing in the disabled would for many seem uncontroversial,
some disability rights groups and ethicists are wary.
They argue that restoring hearing, for instance, could fuel
a prejudice that a deaf life is less rich, or less well lived.
Andy Miah, a professor at the University of the West of
Scotland who has written extensively about human enhancement in
the context of the Paralympics, says it is far from
straightforward.
“For instance, a few years ago, there was a case of a deaf
lesbian couple who sought to use in vitro fertilisation to
select for deafness.
“They argued that absence of hearing is precisely not an
impairment, but allows access to a rich community.”
The ethics become more complex with the prospect of using
these technologies to enhance the able-bodied.
“It’s quite likely that therapy is the back door to
enhancement in these kinds of technological interventions,” says
Miah. “People will question whether this is desirable, but we
already live in a society that tolerates such modifications.
“Laser eye surgery interventions have grown astronomically
over the last decade and nobody complains that it is making
people superhuman.”
For Jan Scheuermann, the experience has been transforming.
“It’s given her a renewed purpose,” said Boninger. “On the
first day that we had her move the arm, there was this amazing
smile of joy. She could think about moving her wrist and
something happened.”
(Editing by Rosalind Russell)
