Stroke victims train brains to see again
|
|
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.
Print Version
Tell-a-Friend comments powered by Disqus
