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Robotic Treadmill Helps Partially Paralyzed

Guided walking seems to retrain brain's movement center, study finds

FRIDAY, Dec. 16, 2005 (HealthDay News) -- Three months of training on a high-tech robotic treadmill helped reactivate a part of the brain linked to walking in patients partially paralyzed after spinal cord injuries, Texas researchers report.

Increased activation in the brain's muscle control center, the cerebellum, was reflected in improved movement ability in three of the four patients in the small study.

The robotic treadmill allows patients to mimic walking in a normal, independent way, rather than having to rely on three therapists working together to manually help them walk. This more natural approach seemed to improve sensory communication between the legs and the brain -- essentially retraining the brain to allow patients to walk.

The technique "provides normal sensory input during walking, and enough practice to cause reorganization in learning in the networks in the brain," explained study author Patricia Winchester, co-director of the Spinal Cord Injury Laboratory at the University of Texas Southwestern Medical Center in Dallas.

Cerebellum activation appeared to be related to how much the patients improved their function, she added. This activation was measured by functional magnetic resonance imaging (fMRI) that was done before and after therapy.

"It appears that the cerebellum plays a critical role in recovery of functional walking," Winchester said. "I could almost line up the patients' functional gains by how their cerebellums lit up."

If further studies confirm these findings, "down the road we could use fMRI's to predict which individuals are going to benefit from [this type of therapy]," Winchester said.

The results appear in the December issue of Neurorehabilitation and Neural Repair.

Approximately 11,000 people annually suffer a spinal cord injuries linked to accidents or illness, according to the Mayo Clinic. Damage to the spinal cord can result in a breakdown of the neurological brain-body "message system" that enables movement.

Spinal cord injuries are classified by two types -- complete, which means that no motor or sensory information can be transferred from below the site of the injury to the brain; and incomplete or partial injury, where there is some transfer of motor and/or sensory information from below the site of the injury to the brain, according to the Mayo Clinic. With rehabilitation, individuals with incomplete spinal cord injury can often regain some use of their limbs.

For the study, Winchester and her colleagues chose four men between the ages of 20 and 49 with incomplete spinal cord injuries. All had some sensory function below the site of their injuries, a range of motion sufficient for standing, and muscle and joint stability that allowed for weight-bearing.

After an initial fMRI, each of the four men had one-hour sessions of robotic treadmill therapy three times a week for three months. At each session, they were strapped into a robotic device called a Lokomat Driven Gait Orthosis (DGO), which enabled them to stand and walk on a treadmill calibrated to be in sync with Lokomat. In this way, the patients' leg movements simulated normal walking.

Following the therapy, study participants had a follow-up fMRI. Winchester and her colleagues compared the activation in their cerebellums with any functional changes they had undergone, noting "how very closely the change in the activation of the cerebellum mirrored the improvement in functional overground walking."

Improvements were striking. One man who had not been able to walk, and another who could only walk with a brace, a walker and physical assistance, managed to both walk again using canes. A third patient who had been unable to walk or stand prior to the training could walk with a walker and some physical assistance following the therapy.

A fourth patient who could not walk before the therapy was not helped by the program. Unlike the other three patients, he showed no increased activation in the cerebellum.

Dr. David Gater, medical director of the Spinal Cord Injury Service at the University of Michigan Medical School, said the jury is still out on whether the robotic approach to physical therapy provides enough active drive from the patient himself. He added that more study is needed to compare the benefits of robotic therapy to traditional rehabilitation, where physical therapists help patients manually.

"Nonetheless, it is interesting to be able to demonstrate that there are functional changes going on," he said. "The cerebellum has tremendous modifying capabilities."

"My bias is that in the long run, exercise is going to be a better means of improving gait than the current emphasis on pharmaceutical and stem cell research," Gater said. "We ought to optimize our rehabilitation strategies, and this is one of those situations that we should invest in fully."

More information

For more on rehabilitation after paralysis, head to the National Spinal Cord Injury Association.

SOURCES: Patricia Winchester, PT, PhD., co-director, Spinal Cord Injury Laboratory, University of Texas Southwestern Medical Center, Dallas; David Gater, M.D., medical director, Spinal Cord Injury Service, University of Michigan Medical School, and staff physician, VA Ann Arbor Health Care System; December 2005 Neurorehabilitation and Neural Repair
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