Robotic treadmill training helps retrain brain, improves walking

People who have suffered partial paralysis from spinal-cord injury show increased activity in the part of the brain responsible for muscle movement and motor learning after 12 weeks of training on a robotic treadmill, researchers at UT Southwestern Medical Center have found.

Their study, which is currently online and will be published in the December issue of the journal Neurorehabilitation and Neural Repair, is the first to demonstrate that locomotor training can promote activation in the parts of the brain involved in walking in spinal-cord injury patients, said lead author Dr. Patricia Winchester, chairwoman of physical therapy at UT Southwestern Allied Health Sciences School. The results suggest that rehabilitation strategies could be designed “based in part upon whether or not they engage the critical areas of the brain necessary for walking,” said Dr. Winchester.

Additionally, the findings suggest that a diagnostic technique called functional magnetic resonance imaging (fMRI), used by the researchers to measure the activation of these brain areas, “may be useful in predicting which individuals will benefit from a particular intervention” after spinal-cord injury, Dr. Winchester said.

David Cunniff, one of the study patients, described his improvements as “quite dramatic.” He said within about a month of training on the robotic treadmill, he stood up out of his wheelchair for the first time. “I had no idea I’d be able to do that,” he said. Prior to the training, he could only stand with assistance and could not walk. Today he uses only a cane to move about. “I don’t think I could have ever gotten to the place I am without the Lokomat robotic device and UT Southwestern,” Mr. Cunniff said.

The study followed four spinal-cord injury patients with varying degrees of paralysis. All underwent rehabilitation therapy using a computerized treadmill called the Lokomat Driven Gait Orthosis. The device supports the weight of the patient in a harness, while robotic devices control their limb movements on a treadmill. During training, the patient watches his or her progress on a real-time computer monitor. By providing sensory information to the spinal cord and brain, the device signals the body to step again.

The study participants were assessed before and after completion of the treadmill training with fMRI. Pictures of blood flow in the brain during body movement were compared to fMRI images taken when the patients were at rest.

After training, those patients who showed the most progress in completing a simple task – flexing their ankles – showed increased activity in the portion of their brains called the cerebellum while undergoing fMRI. However, only those patients who showed a “substantial” change in the cerebellum during the task improved their ability to walk.

Of the four patients, Mr. Cunniff and another man who could walk with a cane after the training had the greatest changes in activation of the cerebellum. Prior to training, the second man required a walker, a brace and physical assistance to walk.

Of the other two patients, one was able to walk with a walker and some physical assistance after the 12-week Lokomat training. Before the training, he had been unable to walk or stand. The fourth patient could not walk before or after training, but nonetheless showed some increased brain activation – but not in the cerebellum – after using the Lokomat.

“The study suggests that the cerebellum plays an important role in recovery of walking,” said Dr. Winchester.

The researchers have now enrolled more than 25 study patients. The next step in the research is to use single positron emission computerized tomography (SPECT) to look at the patient’s blood flow in the brain during the performance of a task. SPECT involves the administration of a radioactive dye that migrates to the patient’s brain and produces a three-dimensional image of hot spots of brain activity.

Other UT Southwestern researchers involved in the study were Dr. Roderick McColl, associate professor of radiology; Dr. Ross Querry, assistant professor of physical therapy; Nathan Foreman and James Mosby, faculty associates in physical therapy; Dr. Keith Tansey, assistant professor of neurology and physical medicine and rehabilitation and director of the Southwestern Spinal Cord Injury Program; and Dr. Jon Williamson, professor of physical therapy.

The study was supported in part by the Western Rehabilitation Research Network.