WASHINGTON - Doctors have had little to offer stroke survivors who lost the use of an arm. Now Alabama scientists report that patients can regain some movement with special intense rehabilitation - forcing them to use the bad arm by tying down the good one - that may help the stroke-damaged brain actually rewire itself.
Surprisingly, even patients who had strokes years ago improved. ''This offers hope that people can get better ... months and years after the damage has occurred,'' said Harvard Medical School neurologist Dr. Seth Finklestein.
But the study, published Thursday in the journal Stroke, has broader ramifications: It's another illustration of how the brain adapts after injury better than scientists once thought, part of doctors' ultimate quest to one day spur that repair process.
''We are on the brink of a revolution in rehabilitation,'' predicts study author Dr. Edward Taub of the University of Alabama at Birmingham, whose brain tests measured an almost doubling of active brain circuitry governing patients' stroke-weakened arms. ''We are, we believe, rewiring the brain.''
Other experts cautioned that while the rehab did help patients, more proof is needed of just what's happening in the brain. The National Institutes of Health has a similar study under way to answer that question.
Doctors once believed the brain was basically hard-wired by early childhood, with certain areas programmed to do certain functions, functions forever lost if cells were destroyed.
But a series of recent discoveries uncovered that the adult brain is remarkably more flexible. Now scientists know the brain continually adapts and reorganizes itself, a condition called ''plasticity.'' For example, brain scans of blind Braille readers show the brain region normally responsible for vision essentially gets taken over by the sense of touch as their fingers race across Braille text.
The question becomes how well adaptation occurs after injury and whether doctors might help spur it along.
Many stroke victims do improve with time - younger patients with smaller strokes have the best chance. Yet for today's more than 4 million stroke survivors, if immediate treatment didn't help their movement, ''the common knowledge is to think there's nothing that can be done,'' said Dr. Leonardo Cohen, whose NIH laboratory is conducting a similar rehab study.
Taub's study suggests intense rehab of the weakened arm helped the brain reorganize itself to compensate for stroke damage.
Patients had to have some residual arm movement to try the therapy. Taub tied down each patient's good arm. Then for six hours a day for 12 days, patients repeated arm exercises, like picking up objects or spooning food.
At first, forcing the arm to move is terribly hard. ''I had to really bear down to get it to do anything,'' said 65-year-old James Faust of Calera, Ala., who tested Taub's therapy two years after a stroke left his arm ''hanging like a rope.''
Then, ''one day it just looked like somebody had flipped a switch. My right arm was doing things I was not able to do prior.'' Today Faust eats, handles lawn equipment and does other everyday activities with his once disabled arm.
Taub's previous studies in more than 150 patients, including Faust, suggested improved arm motion, but many stroke experts remained skeptical. So his new study mapped the brain function of 13 additional patients. He used ''transcranial magnetic stimulation,'' or TMS, a powerful magnet that induces neuronal circuits to fire to measure their activity.
Before rehab, the area of the cerebral cortex that controls hand movement was much smaller on the brain's stroke-damaged side. After treatment, active circuitry on the stroke-damaged side almost doubled, an effect that lasted at least six months, Taub reported Thursday.
Did the area's surviving neurons form new circuits, or did forcing arm movement merely reawaken stroke-numbed circuits?
''We don't really know,'' cautioned stroke expert Dr. Gregory del Zoppo of the Scripps Research Institute. ''But what it implies overall is there's a potential for recovery that's already present and isn't being tapped.''
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