Teaching the Brain to See
Doctors are finding some success in new treatment for patients who suffer vision loss from stroke or trauma
Brain trauma patients with certain visual deficits, including gaps in the visual field, can gain back a good portion of sight by using a novel computer program that retrains brain circuits, scientists have found.
The device, developed by German doctors a decade ago, is making a debut in the United States at Columbia University Medical Center. Dr. Randolph Marshall, a neurologist at Columbia, has tested it with 55 patients, most of whom had at least some restoration of sight. "For patients who experience a 10 to 20 percent improvement, it can be the difference between seeing a piece of paper or just half of it," Marshall said.
The idea of strengthening the visual areas of the brain was born out of work done on stroke patients to strengthen weakened limbs. By tying down the stronger arm, the patient's weaker arm was trained to move more robustly. The brain's motor system was actually repairing itself.
Marshall said that visual deficits occur in 15 percent of stroke or trauma patients, and such problems impair their ability to read, drive and navigate their everyday environment. Like arm strengthening following semi-paralysis, a similar approach is being taken to strengthen the brain's visual system.
Sitting in front of a computer screen, patients fixate on a dot as stimuli appear around it. They press a keyboard button to respond to the geometric shapes that move in patterns across the screen. They do this six days a week for 20 minutes, twice a day.
The customized treatment to stimulate their damaged neurons takes six months, and the results are lasting, Marshall said.
He said that about 65 percent of patients report some improvement. Studies have shown that blind fields are reduced in size by 20 percent.
"We are now trying to figure out what is going on in the brain," said Marshall, who is working with the makers of the device, Nova Vision, to design ways to measure brain plasticity or ability to self-repair. "We think that parts of the brain are taking over for the damaged areas."
The therapy is not offered right away because there is a small window of time when spontaneous recovery from stroke occurs. Vision problems occur during the actual episode and usually don't get worse over time.
Vision therapy is being offered after three months. Because it is a new technology, the company is still seeking medical reimbursement. The six-month treatment costs $6,000, which includes a detailed mapping of the patient's visual field. The therapy is built around this map.
Scientists suspect that visual restoration therapy restores the partially damaged neurons that are trying to compensate after injury.
This technology is forcing neighboring cells around the area of damage in the visual cortex to turn on, taking over for the dying cells.
By Jamie Talan, Newsday Staff Writer
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