Implantable electronic devices have shown promise in helping medical patients regain functionality in various limbs after paralysis injuries. Last week, the Mayo Clinic announced that one such device has allowed a paralyzed man to begin walking with assistance.

Joint research from the Mayo Clinic and UCLA, as well as a new study from the University of Louisville, shows that electrical stimulation of the spinal cord has helped paralyzed patients learn to walk by using their own brain power.

UCLA and the Mayo Clinic, based in Rochester, MN, published research in Nature Medicine showing that epidural electrical stimulation allows a paralyzed patient to walk. A patient named Jered Chinnock, who was paralyzed in a 2013 snowmobile accident, was able to walk 111 yards (longer than the length of a football field) with the help of a front-wheeled walker. This was accomplished during extensive rehabilitation—113 visits to the clinic over a year-long process.


Jered Chinnock walking with assistance. Image used courtesy of Mayo Clinic


Researchers say the Mayo Clinic's research with UCLA represents a breakthrough after years of research in into electrical stimulation, which built upon earlier research from the University of Louisville and other studies into the potential for electrical stimulation.

“The hypothesis – from our team after this work, and from others who have been in this field of epidural stimulation for years—is that epidural stimulation may enhance spinal network activity in the spinal cord so that these networks can receive weak, descending signals from the brain,” according to Dr. Kendall Lee, the co-principal investigator, neurosurgeon and director of the clinic’s Neural Engineering Laboratories.

“These signals may be crossing the injury and integrating information from the brain and sensory information from the legs to produce coordinated, robust motor functions needed to step or stand.”

The implant device is approved by the FDA for other use, according to Dr. Lee, but not spinal cord injuries, and is being used under a special investigational device exemption. The device, from Medtronic, is a 16-contact electrode array that is connected to an implanted pulse generator that is placed subcutaneously in the upper right quadrant of the abdomen, he said.


The spinal implant device. Image used courtesy of Mayo Clinic


Kristen Zhou, PhD, co-principal investigator and director of the Mayo Clinic’s Assistive and Restorative Technology Lab, said that additional research needs to take place to determine who benefits from this type of therapy. Zhou said the team is interested in how epidural stimulation improves several key elements of daily living, including bowel, bladder, and sexual function.

The Mayo Clinic research with UCLA essentially replicated earlier research done at the University of Louisville. UCLA professor V. Reggie Edgerton said the new research at both universities has helped fill in gaps in how the mind helps controls body functions.

“In part, it has been due to a lack of understanding of some basic physiological principles about how we control movement,” he said. “But the second factor is that the available technologies have not been developed to be user-friendly and/or properly designed for human use.”

Officials led by Susan Harkema, PhD, and associate director of the Kentucky Spinal Cord Injury Research Center at the University of Louisville published findings in the New England Journal of Medicine showing how epidural stimulation and locomotor training helped help four paralyzed patients learn to stand and in two cases walk with the help of walkers.