NEW YORK (Reuters Health) - In a development that may offer hope to some people with spinal cord injuries, Arizona researchers report that a partly paralyzed man can now walk several hundred meters after having electrodes implanted in his lower back.

When used in combination with rehabilitation on a treadmill, the electric impulses delivered by the electrodes seem to have helped the spinal cord's circuitry "relearn" how to walk, according to Dr. Richard Herman of Arizona State University in Tempe.

The man still has to use a wheelchair, but he is able to walk on his own during his daily activities, such as trips to the bathroom and from the car to restaurants and shops, Herman told Reuters Health in an interview.

"There's a possibility that wheelchair-dependent people can walk again," Herman stated.

But the Arizona researcher stressed that the technique is not expected to benefit all people with spinal cord injuries. The man who was able to walk again had a so-called incomplete spinal cord lesion, Herman noted, meaning that his spinal cord had not been severed completely. After the injury, he still had some sensation in his legs, although he had no useful muscle strength, Herman explained.

Herman also noted that the treatment is in the very early stages. The researchers have since implanted the electrodes in a second patient, but the technique needs to be studied in many more patients, Herman said.

Herman and his colleagues report the results of the treatment in the February issue of the journal Spinal Cord. The patient was a 43-year-old man who was dependent on a wheelchair more than 3 years after having an injury that partially severed his spinal cord.

The man first underwent rehabilitation on a treadmill before electrode implantation. He was placed on the treadmill, but he was supported by a harness that bore most of his weight. Physical therapists worked with the man to walk at various speeds, and as he improved, he gradually supported more and more of his own weight.

Eventually, Herman said, the patient was able to walk about 1.5 miles an hour, which was an improvement, but still lagged behind the normal pace of an uninjured person, which is about 2.5 to 3 miles per hour. He was able to support only about 70% of his weight, which meant that he would have to rely on a walker to travel any considerable distance, according to Herman.

After the treadmill therapy, it took the man about 2.5 minutes to walk 15 meters, or about 50 feet.

But his walking abilities dramatically improved after a pair of electrodes were implanted in his lower back.

When the patient wants to walk, he places a disk on the skin over the electrodes, Herman explained. This disk receives signals from a remote device. These signals excite the circuitry in the spinal cord that is responsible for movement and rhythm, he said.

The activation of the electrodes slashed the amount of time it took the man to walk 15 meters, and he continued to improve with practice. About 6 weeks after he started using the electrodes, he could walk 15 meters in less than a minute. And after 4 months, he was able to walk 270 meters, or almost one-fifth of a mile.

"He's reached levels of function that we didn't anticipate," Herman said.

And walking has become nearly effortless for the man, Herman pointed out. The patient says his legs feel very light and he does not feel fatigued after walking.

The man still has to use a wheelchair, but the combination therapy has allowed him to be more independent in his daily life, Herman added.

The researchers have implanted the electrodes in a second patient and hope to treat a third in the future. At that point, the US Food and Drug Administration (news - web sites) will review the data, Herman said.

Eventually, the researchers would like to see if the combination of treadmill training and electrodes will benefit people with more severe disability, Herman noted.

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