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Stroke victims train brains to see
again
Chicago -
A new study bolsters evidence that people partially blinded
by a stroke or brain injury may be able to improve their field of
vision by teaching new parts of their brain to see, U.S. researchers
said on Thursday.
Using a computer workout program
for the brain, about three-quarters of patients in the study could
see better after six months of treatment with the therapy, which
trains neighboring brain cells to take over for damaged areas.
The therapy, which is marketed by
NovaVision of Boca Raton, Florida and won U.S. Food and Drug
Administration approval in 2003, is controversial among neurologists
because it challenges the widely held belief that vision lost
through brain injury or stroke can't be treated.
A German study published in the
British Journal of Ophthalmology in 2005 pronounced the therapy a
flop.
But NovaVision says the latest
study, conducted on patients in the last two years and whose results
were presented at the International Stroke Conference in San
Francisco on Thursday, reinforces its contention that the treatment
works.
NovaVision
says the results of the therapy proved the brain is plastic, capable
of rewiring itself even long after an injury. The idea of "neuroplasticity"
has been used to help stroke patients recover lost speech and
movement but vision had been thought to be immutable.
"It makes no sense to believe there
is no plasticity in the visual cortex," said Dr. Jose Romano, a
neurologist at the University of Miami who conducted the study and
serves on NovaVision's scientific advisory board.
Vision restoration therapy could
help the 1.5 million stroke or brain injury victims in the United
States who have visual defects that make everyday tasks like reading
and watching television a challenge, the company says.
SEEING MORE
Romano and colleagues evaluated 161
patients who underwent treatment at 16 U.S. research centers for six
months.
Using a special laptop and attached
chin rest, patients stared at a fixed dot while various lights
flashed along the border of their blind spot. They clicked a
computer mouse each time they could detect the flash of light.
After six months of twice daily
therapy, 76 percent of patients were helped, regaining on average 5
degrees of their visual field, Romano said in an interview with
Reuters.
That is roughly the equivalent of a
hand held at arm's length, then moved five inches to the right or
left. "It allows you to read and to not bump into things," Romano
said.
Stroke researcher Randolf Marshall
of Columbia University Medical Center in New York, who has used the
therapy in his own practice, examined six patients before and after
one month of therapy using functional magnetic resonance imaging or
fMRI.
Marshall, who has no ties to
NovaVision, found that all six showed increased activity in the area
of the brain bordering the injury.
"The brain has essentially learned
to use more of its activity ... in this particular trained location.
We are really looking at a pattern of learning," he said.
Last month, NovaVision raised $20
million in its third round of financing, snagging Johnson & Johnson
as one of its investors. The $6,000 treatment is not covered by most
insurance, but the company is seeking reimbursement under the U.S.
government's Medicare health program for the elderly.
-- Reuters News
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