Researchers in UofL’s provided a combination therapy to five children with complete paralysis. The children, ages 7-12, took part in a clinical study in which they received external electrical stimulation over the spine, combined with activity-based therapy and encouragement to consciously intend to step. During the study, the children all gained the ability to take steps and experienced unexpected improvements in sensation, bladder function, transferring and other abilities. The study was published in the.

“We have found that electrical stimulation can “charge” the spinal cord, making it possible for a paralyzed individual to step voluntarily,” said Andrea Behrman, professor in the UofL Department of Neurological Surgery and director of the Center for Pediatric NeuroRecovery, who led the study. “This ability increases over time when the stimulation is combined with locomotor training and mental intent to step.”

Stimulation + activation + intent

In the study, children who were completely paralyzed for more than a year, unable to move below their level of spinal injury, participated in a series of 60 sessions that included noninvasive, transcutaneous (through the skin) electrical stimulation of the sensory nerves to the spinal cord and specialized physical therapy.

The electrical stimulation was applied with a specially designed technique for external electrical stimulation developed by Yury Gerasimenko, now gratis professor of the UofL Department of Physiology. The technique consisted of several small stimulators, about the size of a quarter, placed on the child’s skin over the sensory nerves of the spinal cord. During the sessions, electrical stimulation was applied through the pads while the children took part in physical therapy known as activity-based locomotor training.

This therapy consists of researchers and therapy technicians manually facilitating the child’s legs in stepping motions as they lay on their side on a table with their legs suspended and also during assisted walking with part of their body weight supported over a treadmill. In addition, the children were encouraged to consciously attempt to step.

Over the course of the study, the children were able to initiate and control the stepping themselves. After various numbers of sessions, they were able to take steps over ground, voluntarily initiating the steps both with and without the stimulation present. Three to six months after the sessions were completed, all of the children still were able to take steps with and without the stimulation.

“The results we see with this study confirm what I have learned more and more over the last two decades working with children with spinal cord injury,” Behrman said. “Your spinal cord is more than a conduit or a pipeline for nervous system messages. It processes information and is smart like your brain. The spinal cord can’t decide to go to Starbucks for coffee, but it can help you with more automatic movements such as sitting up better and taking steps. It also works somewhat like a battery and needs the right charge to help produce steps and respond to therapy.”  

For many years, the medical community as a whole has believed that after injury in which communication along the spinal cord was interrupted and the patient could not move on their own, that function below the injury could never be restored. As a result, treatment for most people with complete paralysis included helping them adapt to mobility with wheelchairs and other forms of assistance.

For the parents of children participating in Behrman’s studies and clinical care, even the small gains achieved through the sessions have a significant positive impact on their child’s quality of life and often, their health.

Kalyn MacIntyre, whose son Malcolm participated in the study, said that even three years after the study concluded, he retains many of the benefits he gained from his sessions.

“He can still step on the treadmill, he can kick a ball consistently. He can now feel when he needs to go to the restroom and his overall health has been good,” Kalyn said, adding that he also has sensory gains. “I don’t know what his future is as far as walking. I just want him to be functionally capable of doing things on his own – to have more independence – and I want him to be healthy. We have more of that here because of this study.”

The personal connection

One of the most challenging aspects of the research is motivating the children during long training sessions.

“We can have the most beautifully designed study, but if a child can’t get into it and you can’t help them be successful, it will not work,” Behrman said. “You can’t just come in and say, ‘Do this 50 times.’ For each child, you must figure out how to connect with who they are.”

To engage them in the activities, Behrman and the therapists working with the children have cultivated the art of motivation by incorporating their personal interests. One child in the study was a basketball player before he was injured, so Behrman used a whistle to encourage him to go faster or drive harder, similar to when he was running drills for basketball.

For Malcolm, the research staff devised a point system to reward him for every time he was able to kick a ball. Behrman recalled one session when she told him that instead of the 10 or 20 points he received for kicking the ball off the treadmill, she would award him 10,000 points if he could kick the ball to hit a target on the opposite wall.

On the next try, Malcolm’s kick sent the ball sailing across the room, squarely hitting the target.

Previous success

Previously, researchers at UofL achieved remarkable success in restoring function to adults with spinal cord injury in studies using surgically implanted electrical spinal cord stimulators. In one study, adults who were completely paralyzed were able to take steps over ground with stimulation after a series of intensive physical therapy sessions and mental intent to take steps.

This new study shows that similar results can be achieved without the invasive procedure. In addition, the adults could only step when the stimulator was on, whereas the children in Behrman’s study were able to step long after the stimulation sessions had ceased.

For additional photos and video clips, visit . All images courtesy University of Louisville. The images with “study image” in the name were captured during the study sessions, 2021-2023.

Andrea Behrman, PhD, of the UofL Department of Neurological Surgery and the (KSCIRC), pioneered the use of locomotor training in children at UofL since 2012. Until now, however, Behrman’s team has used treadmills and harnesses designed for adults that have been adapted for children. The oversized equipment is cumbersome for children and working on cut-down adult-sized devices has resulted in unnecessary strain for the trainers and therapists who work with them.

So, Behrman enlisted Tommy Roussel, PhD, of the at UofL, to engineer a treadmill and harness system specifically for young children. Using engineering expertise, user feedback and a patent held by Susan Harkema, PhD, professor of neurosurgery and a pioneer in spinal cord injury research in adults at UofL, a new treadmill was designed from the ground up just for children. 

“It was kind of like putting a kid on an adult bicycle or watching kids play basketball with a 10-foot goal,” Roussel said. “So we have redesigned the system with the same operational capacity, but with kids in mind.”

The new pediatric treadmill has multiple advantages for both children and trainers:

• Suspension tower is located behind the child on the treadmill so therapists can more easily and directly engage with the child
• Narrower tread, focusing the child’s steps and bringing trainers closer to the child’s legs and feet
• Trainers’ seats are more appropriately positioned closer to the child and are adjustable to accommodate trainers of different heights
• Treadmill tower swivels to allow the child to be hoisted from a wheelchair and onto the treadmill
• Smaller, more adaptable harness that is more comfortable and easier to adjust to the child’s changing capability

“The treadmill is a tool for us, but we want it to be a smart tool. By making it better, we are going to do our jobs better and the child is going to participate better,” Behrman said. “We changed it to make the child more accessible to the trainer with good body posture and position for all this repetitive activity.”

Thanks to funding and support from the , the team was able to develop the initial prototype. Behrman and Roussel then collaborated with other specialized manufacturers, further refining the treadmill and harnesses. Once they had a customized treadmill, the team worked to commercialize the device and harness system to make it available to therapists in other centers.

“We starting thinking, ‘How can we make it better?’” Roussel said. “If we are going to move to manufacturing this, how can we make it more modular and with fewer parts that need to be assembled? That’s where the magic and the fun happened.”

The treadmill design was licensed to and units are in place or on their way to facilities in Pittsburgh, Houston and New York, as well as in Louisville at Frazier Rehab Institute.

“In the last several years, we have been able to achieve things that have not historically happened in terms of rehabilitation outcomes for these children,” Behrman said. “Children once unable to sit on their own, for example, can now do so due to locomotor training. Such improvements open up other possibilities to play and engage, and help a child get back on the developmental track. This new treadmill system gives physical therapists and trainers a device that is state-of-the-art in design and utility and revolutionizes the way we deliver locomotor training specifically for children.”

Check out video of the new treadmill system:

Donors and developers include: Christopher and Dana Reeve Foundation, Kosair Charitie, WHAS Crusade for Children, Independent Pilots Association Foundation, Ty Adams, Jena Allen, Laura Argetsinger, Andrea Behrman, Yangsheng Chen, Ran Cheng, Susan J. Harkema, Dena Howland, Winston Rauch, Tommy Roussel, Shelley Trimble, Winston Industries, Haffendorfer Machine Inc., Tuff Tread Treadmills, Rich and Norrie Oelkers and the Bonita Bay Tennis Club, Goose Kearse, Rachel Marsilia, MacKenzie Roberts and Misty Mountain Threadworks.