Epidural Stimulation for SCI Shows Contintued Progress
by James Cavuoto, editor
September 2018 issue
Research institutions and commercial firms pursuing epidural stimulation as part of a new therapeutic approach for treating spinal cord injury have continued to show progress. In recent weeks, investigators at three institutions in the U.S. published findings that broke new ground.
Earlier this month, a team of researchers from the Mayo Clinic and UCLA published results in Nature Medicine showing that neuromodulation of lumbosacral spinal networks enabled independent stepping after complete paraplegia. After 43 weeks of epidural stimulation teamed with dynamic task-specific training—a therapy the authors refer to as multimodal rehabilitation—a 26-year old subject at Mayo clinic with T6 complete paralysis was able to produce bilateral stepping on a treadmill without trainer assistance or a body-weight support system. The subject was also able to step independently over the ground with the help of a front-wheeled walker. The stepping was only possible when the stimulator was on.
The Mayo-UCLA team included Reggie Edgerton, chief scientist and founder of commercial firm NeuroRecovery Technologies Inc., and Kendall Lee, a neurosurgeon at Mayo Clinic.
Also this month, a research team at the University of Louisville’s Kentucky Spinal Cord Injury Research Center published findings in JAMA Neurology described positive results of epidural stimulation in four subjects with complete paralysis resulting from SCI. The participants experienced improvements in blood pressure and heart rate regulation during and after stimulation. All four participants had chronic, complete cervical spinal cord injury, persistent low resting blood pressure, and blood pressure decrease when sitting up prior to stimulation.
“From a quality of life perspective, orthostatic hypotension, or low blood pressure when sitting up, is truly life limiting,” said Glenn Hirsch, a cardiologist with the UofL School of Medicine and coauthor of the study.
For this study, research participants received stimulation using specific configurations selected to target cardiovascular function, monitoring blood pressure and cardiovascular function throughout, for an average of 89 daily, two-hour sessions. Earlier research showed the benefits of epidural stimulation in controlling cardiovascular function during stimulation, but this new data reveals participants’ blood pressure and heart rate remained stabilized between sessions, showing an enduring effect.
“What was most surprising was that only having it on for a few hours a day, we were noticing participants having normal blood pressure through longer periods of each day,” Hirsch said. “We are noticing it now across the research participants who had that problem, that there is a prolonged stabilizing effect even after the stimulator is turned off.”
“In our motor system studies, we observed that we could actually regulate blood pressure without activating the motor system. That launched us into another area of research,” said Susan Harkema, associate director of KSCIRC and professor of neurosurgery at UofL. “Many people don’t realize that walking in many cases is not really the aspect that makes their daily lives most difficult because they have cardiovascular dysfunction and problems with respiratory, bowel, bladder, and sexual function. All of those things are disrupted so every day is incredibly difficult for people with SCI.”
In ongoing research to explore further the life-enhancing effects of epidural stimulation, the UofL researchers are conducting a six-year study with 36 participants with chronic, complete spinal cord injuries.