Reason to smile. stimulation of the injured spinal cord of Rob Summers has restored a voluntary movement.
The Lancet
Five years, Rob Summers was 20 years old and about to enter his first year State University of Oregon in Corvallis, where he was a baseball team's pitcher. One night when he went out to get a gym bag from his car, another car jumped the curb, hit him, and then took off. Summers was paralyzed from the chest down. Today, in a case report published in The Lancet , physicians and researchers reveal that Summers has regained the ability to stand for a few minutes and do some voluntary movement of his legs, through electrodes they implanted in his spinal cord.
Other researchers say that the degree of recovery is remarkable, perhaps even unprecedented, but they warn that the procedure has not produced a complete cure and may not work as well for patients who are older or have more serious injuries. At a press conference today announcing the results, the researchers who conducted the study, neuroscientists V. Reggie Edgerton of the University of California, Los Angeles, and Susan Harkema of the University of Louisville Kentucky, framed their method as a way to make the most of the neural circuit that remains intact after an injury to the spine, as opposed to restoring the severed connections.
After his injury, Summers was unable to move his legs or trunk, although he had some ability to feel a light touch or bite in these areas. Two years of intensive physical therapy have failed to restore voluntary movement. The reason for spinal cord injuries cause lasting paralysis is that neurons in the adult spinal cord can not sprout new axons armlike extensions that neurons use to connect to each other. As a result, parts of the cerebral cortex that plan and initiate movements remain disconnected from spinal neurons that normally help their bidding.
In December 09, Summers became the first patient enrolled in a clinical trial of a pioneering method in studies with rodents and cats by Edgerton and others. Louisville surgeons placed a small strip of electrodes on the hard, protective layer surrounding the spinal cord. Summers has regularly undergone physiotherapy sessions during which the researchers spent pulses of electrical current through the electrodes to stimulate neurons in the spinal cord. After a few sessions, Summers was able to stand with assistance. At the end of 80 sessions over 7 months, Summers was able to stand up and support his own weight for several minutes and, with help, to step. Lying in bed, he was able to move his toes, feet and legs on command. Although these exploits require the pacemaker to be on, Summers also reported improved bladder control and sexual function, even with the stimulator off, Edgerton and colleagues reveal in The Lancet paper.
Research in animals with lesions of the spine showed that this type of epidural stimulation can activate neural circuits in the spinal cord and allow them to use sensory information to coordinate leg contractions necessary to act and take a step muscle, Edgerton said at the press conference. The results show for the first time that this method works in humans, Edgerton said.
"This is the first time someone with complete, chronic motor paralysis demonstrated any type of voluntary movement," said Gregoire Courtine, a neuroscientist at the University of Zurich in Switzerland.
"it is an individual, so you should take it with a grain of salt," says Michael Beattie, a neuroscientist at the University of California, San Francisco. "on the other hand, it is really very impressive." the fact that Summers has taken a voluntary movement suggests that at least some nerve fibers from the cortex to the spinal cord should have been spared by the injury, Beattie said. He noted that patients with spinal cord severed probably could not recover all voluntary movements.
in a press release issued by the Lancet , Summers said the treatment has done wonders for his sense of well-being. "This procedure has completely changed my life for someone who for four years was unable to even move a toe, to have the freedom and ability to stand on my own is the most amazing feeling. "
Although Courtine think there is still much room for improvement. Improvements to the design of the stimulation electrodes and more sophisticated models of electrical stimulation could produce better effects. So could stimulant, in conjunction with injections of drugs into the liquid bathing the spinal cord to improve neuronal repair, he said.
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