Shaping and Massed Practice Rehabilitation
In May 1981 Edward Taub was forty-nine, heading up his own lab, the Behavioral Biology Center in Silver Spring, Maryland, with grand plans to transform the work he was doing with monkeys into a treatment for stroke. But these plans got waylaid by an eager young volunteer he hired to work in his research lab. His name was Alex Pacheco and, although he told Taub he was considering becoming a medical researcher, he was actually the cofounder and president of People for the Ethical Treatment of Animals (PETA), the militant animal rights group.
Pacheco's goal was to free the seventeen "Silver Spring monkeys" and
make them a rallying cry for an animal rights campaign, and he did just that when Taub went away on vacation for a few days. When he returned, his life was thrown into an uproar. He was arrested and put on trial for cruelty to animals, charged with 119 counts. He suffered professional isolation; lost his salary, his grants, and his animals; was prevented from experimenting; and was driven from his home in Silver Spring.
In the end, the charges were dropped and he regained the support of NIH and 67 other professional societies, but undoing all the damage would take years. It meant starting over from scratch, which he did in 1986 when he was hired by the University of Alabama. He got a grant to study strokes and leaped at the opportunity to test out his theories on actual patients.
In 1987 he opened the Taub Clinic and purchased crates of slings and mitts, required garb for the dozens of stroke patients he treats at this facility. Mitts go on good hands and slings go on good arms and are required wear for 90% of every day.
In his early work with monkeys, Taub had learned an important lesson. If he simply offered them a reward for using their bad arms to reach for food — if he tried to do what behaviorists call "conditioning" — the monkeys made no progress. He turned to another technique called "shaping," which molds a behavior in very small steps. So, a deafferented animal would get a reward not only for successfully reaching for the food but for making the first, most modest gesture toward it.
The Taub clinic always uses the behavioral technique of "shaping," taking an incremental approach to all tasks. Adults play what look like children's games: some patients push large pegs into peg-boards, or grasp large balls; others pick the pennies out of a pile of pennies and beans and put them in a piggy bank. The game like quality is no accident — these people are relearning how to move, going through the small steps we all went through as babies, in order to retrieve the motor programs that Taub believes are still in the nervous system, even after many strokes, illnesses, or accidents.
Conventional rehab usually lasts for an hour, and sessions are three times a week. Taub patients drill six hours a day, for ten to fifteen days straight. Patients do ten to twelve tasks a day, repeating each task ten times apiece. Improvement begins rapidly, then lessens progressively. Taub's original studies showed that treatment works for virtually all stroke survivors who are left with some ability to move their fingers — about half of patients who have had chronic strokes.
Currently Taub is studying what length of training is best. He has begun to get reports from clinicians that three hours a day may produce good results and that increasing the number of movements per hour is better than undergoing the exhausting six hours of treatment. What rewires patients' brains is not mitts and slings, of course.
Though they force the patients to practice using their damaged arms, the essence of the cure is the incremental training or shaping, increasing in difficulty over time. "Massed practice" — concentrating an extraordinary amount of exercise in only two weeks — helps rewire their brains by triggering plastic changes
Many of these people have had severe chronic strokes and showed very large improvements. Even patients who had had their strokes, on average, more than four years before beginning CI therapy benefited significantly.
Excerpted from her book: The Brain That Changes Itself
Stories of Personal Triumph from the Frontiers of Brain Science
By Norman Doidge, MD, Penguin Publishing, December, 2007