Reeve confounds medical experts again
The Associated Press
WASHINGTON — Seven years after actor Christopher Reeve was paralyzed from a spinal-cord injury, tests show his brain has maintained a near-normal ability to detect feeling and direct movement. The finding suggests the "use it or lose it" rule might not apply to the brain after all, experts say.
Years of research in animals has shown that when the spinal cord is severed, cutting off signals to parts of the brain, the brain will reorganize itself and eventually not respond to signals from the paralyzed part of the body.
But a study by researchers at Washington University School of Medicine in St. Louis, using an MRI technique, shows that might not be true for Reeve.
"We see evidence of some reorganization in this patient," said Dr. Maurizio Corbetta, a Washington University neurology researcher. "But we also see strong evidence for stability ... which goes against the principle of 'use it or lose it.' "
"We are very encouraged with these results," said Corbetta, the first author of a study in the Proceedings of the National Academy of Sciences.
Other experts cautioned that the study deals with one patient and that extensive studies would be needed to determine whether the findings are true in other patients with spinal-cord injuries.
Reeve, who played Superman and other roles in movies, was left paralyzed from the shoulders down after breaking his neck in a fall from a horse in 1995. The fall severed most of the nerves in the spinal neural bundle that carries signals between his brain and the rest of his body.
He started a program of exercise and electrical muscle stimulation in 1999, and doctors announced earlier this year that the actor has experienced a slow rebirth of limited sensation and movement. At the time, some doctors called it "an unprecedented amount of recovery" for a patient with such an injury.
Corbetta said the new studies show Reeve may be exceptional in another way — his brain has remained receptive to signals from the paralyzed portion of the body even though most of those signals were interrupted by the injury.
Some researchers, based on the animal studies, have suggested that repairing the spinal cord would do little good because the brain has effectively given up on the paralyzed portions of the body and has changed so it no longer could process those signals.
"The usual argument is that the brain has reorganized so what good is it going to do (to repair the spinal cord)?" Corbetta said. "At least in this case, some of the responses are more normal than we would have expected. So there is new hope."
Corbetta said he and others at Washington University used an MRI to map the patterns of brain activity in response to touch and movement. For the movement study, Reeve followed the video image of a tennis ball and indicated the direction with either his tongue or the movement of the left index finger.
As this occurred, the MRI detected the active parts of the brain.
"There is a picture of your body plotted on the brain," Corbetta said, "with different parts of the brain driving different parts of the body." MRI, in effect, maps the areas that respond to specific actions or sensations.
The researchers then compared Reeve's results with those of an identical test conducted on an able-bodied 23-year-old and found only slight differences.
"We were surprised with the results," said Dr. John W. McDonald, a Washington University researcher.
Corbetta said Reeve's brain was "pretty much normal on the sensory maps. He had feeling in both his foot and his hand." For motion, Corbetta said he found that areas of the brain that normally control the hand had been taken over, to some extent, by areas that control the face. The brain circuits linked to the foot were normal.
Reeve said he was excited by the results.
"I find it very encouraging, not only for myself, but for other spinal-cord injury patients as well," he said. "It means that there are no absolutes and patients should be encouraged to push as far as they can."