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Four young men who have been paralyzed for years achieved groundbreaking progress – moving their legs – as a result of epidural electrical stimulation of the spinal cord.
The breakthrough was reported by an international team of life scientists at the University of Louisville, UCLA and the Pavlov Institute of Physiology today in the medical journal Brain. The study was funded in part by the Christopher & Dana Reeve Foundation and the National Institutes of Health and the Leona M. and Harry B. Helmsley Charitable Trust.
All four participants were classified with a chronic motor complete spinal cord injury and were unable to move their lower extremities prior to the implantation of an epidural stimulator. This research builds on an initial study, published in the May 2011 edition of The Lancet, which evaluated the effects of epidural stimulation in the first participant, Rob Summers, who recovered a number of motor functions as a result of the intervention.
Now three years later, the key findings documented in Brain detail the impact of epidural stimulation in four participants, including new tests conducted on Summers. The second, third and fourth participants were able to execute voluntary movements immediately following the implantation and activation of the stimulator. The results and recovery time were unexpected, leading researchers to speculate that some pathways may be intact post-injury and therefore able to facilitate voluntary movements.
“Two of the four subjects were diagnosed as motor and sensory complete injured with no chance of recovery at all,” said lead author Claudia Angeli, Ph.D., senior researcher, Human Locomotor Research Center at Frazier Rehab Institute, and assistant professor, University of Louisville’s Kentucky Spinal Cord Injury Research Center. “Because of epidural stimulation, they can now voluntarily move their hips, ankles and toes. This is groundbreaking for the entire field and offers a new outlook that the spinal cord, even after a severe injury, has great potential for functional recovery.”
These results were achieved through continual direct epidural electrical stimulation of the participants’ lower spinal cords, mimicking signals the brain normally transmits to initiate movement. Once the signal was triggered, the spinal cord reengaged its neural network to control and direct muscle movements. When coupling the intervention with rehabilitative therapy, the impact of epidural stimulation intensified. Over the course of the study, the researchers noted that the participants were able to activate movements with less stimulation, demonstrating the ability of the spinal network to learn and improve nerve functions.
“We have uncovered a fundamentally new intervention strategy that can dramatically affect recovery of voluntary movement in individuals with complete paralysis even years after injury. … The belief that no recovery is possible and complete paralysis is permanent has been challenged,” said Susan Harkema, Ph.D., Owsley Brown Frazier Chair in Clinical Rehabilitation Research at the University of Louisville, rehabilitation research director at KSCIRC, Frazier Rehab Institute, director of the Reeve Foundation’s NeuroRecovery Network and primary author of The Lancet article.
Beyond regaining voluntary movement, the research participants have displayed a myriad of improvements in their overall health, including the increase of muscle mass and regulation of their blood pressure, as well as reduced fatigue and transformational changes to their sense of well-being. Additionally, all four men were able to bear weight independently, as reported by the team.
With nearly six million Americans living with paralysis, including 1.275 million spinal cord injuries, this study confirms a significant breakthrough in terms of developing clinical therapies to advance the treatment of paralysis, according to a UofL press release.
As the first epidural stimulation participant, Rob Summers “moved the needle for the entire field with his unprecedented recovery.” He was paralyzed below the chest after being struck by a vehicle in 2006. Summers currently resides in Portland, Ore. The other three research participants include:
Kent Stephenson – the second person to undergo epidural stimulation after sustaining an injury during a motocross accident in 2009. He resides in Mount Pleasant, Texas.
Andrew Meas – the third person implanted after a motorcycle accident in 2007. He lives in Louisville.
Dustin Shillcox – the fourth participant. He was injured his spine in an auto accident in 2010. He lives in Green River, Wyo.
“With this study the investigators show that their findings about a motor complete patient regaining movement, as published three years ago in The Lancet, were not an anomaly,” said Susan Howley, executive vice president for research at the Christopher & Dana Reeve Foundation. “At the present time, other than standard medical care, there are no effective evidence-based treatments for chronic spinal cord injury. However, the implications of this study for the entire field are quite profound and we now can envision a day where epidural stimulation might be part of a cocktail of therapies used to treat paralysis.”
Epidural stimulation, in the context of paralysis of the lower extremities, is the application of continuous electrical current, at varying frequencies and intensities to specific locations on the lumbosacral spinal cord, corresponding to the dense neural bundles that largely control movement of the hips, knees, ankles and toes.