Unprecedented. There’s only so much you can spin into a headline before it breaks under the weight of misdirection and exaggeration. For careful readers, this one holds the load.
Here we have a remarkable study with a young man with a chronic, complete C7-T1 spinal cord injury and no muscle control below mid-chest. An electrical stimulator was surgically placed over his lumbar spinal cord; when turned on, he was able to rise up from his chair, fully bear his weight, and stand. That is unprecedented functional recovery. The epidural stim does not directly affect his leg muscles, it activate circuits of the spinal cord. These circuits are not directly controlled by the brain; on its own, the lumbar cord is smart.
What’s more, after months of intense locomotor training on a treadmill, the subject was able to voluntarily initiate stepping. And here’s even more, this part surprising, quoting the paper released online May 20 in the medical journal Lancet:
“After training and epidural stimulation, the patient also had functional gains in bladder and sexual function and temperature regulation. The patient is now able to voluntarily void with minimum residual volume of urine and has reported improved sexual response and performance. The patient regained diaphoretic capability [sweating] and the ability to tolerate extremes of temperature. Additionally, the patient reported that a sense of wellbeing and increased self-esteem enabled more frequent social interactions.”
What appears to be happening is that increased activity and training might have awakened neural circuits that were intact but not working, or promoted nervous system remodeling, or plasticity.
Why this is so cool: recovery of movement after complete SCI is possible, and won’t necessarily require regeneration or replacement of damaged nerve connections between brain and body. A new strategy may emerge, taking advantage of the body’s powerful ability to reorganize spinal nerve circuits, based on activity. Imagine taking this training-based recovery and adding some yet-to-come biological or regenerative therapy – now that could lead to breakthrough headlines.
Again, from the Lancet paper:
“These findings open the possibility of a paradigm shift in the perception of possible interventions that could be used to improve function for a range of neuromotor disorders.”
First, before getting into great detail about this research, be sure to read the
press release. And for a good lay-language overview, see the
FAQ.
Obviously there is excitement at the Reeve Foundation, which helped fund this work. The lead authors are key members of the Reeve research effort: Susan Harkema, Kentucky Spinal Cord Research Center, University of Louisville, KY, heads the Reeve
NeuroRecovery Network (based on the same activity based concepts).
Reggie Edgerton, Department of Integrative Biology and Comparative Physiology, University of California, Los Angeles, is a member of Reeve’s
International Research Consortium on Spinal Cord Injury and serves on the Foundation’s Science Advisory Council.
There is caution, too, not to oversell this. The data certainly justify the mood, but this case study is not a treatment. Not a cure. It is a proof of concept, perhaps, that there are ways paralyzed people can move without resetting nerve connections between the brain and the lower extremities. There is plenty to work out before this is widely available.
Keep in mind, this is a science experiment, not a clinical trial. In the lexicon of research, this an “N of one” study. N is the number of patients. What happened to Rob Summers is of great interest to the scientists and to the field of research, and of course to the SCI community. There are many ways to speculate about where this might go from here. But what’s making news here is based on only one person; it isn’t fair to make generalizations until several other patients get similar results. At this time, there is one other patient in the study; he has not yet been implanted with the stimulation device.
Note: patients are not being recruited at this time. When trials do occur, information will widely distributed. To learn more about the ongoing studies, contact the University of Louisville/Frazier Rehab Institute at www.spinalcordmedicine.com or call 1-866-540-7719. Specific questions can be emailed to: info@spinalcordmedicine.com
Meanwhile, some of the hurdles ahead have been identified. The stimulator used in this study was rather crude. It was an off-the-shelf model commonly used to treat pain. There are newer stim units being developed now to fine-tune the lumbar response.
In animal studies, epidural stim was greatly enhanced using a drug (quipazine) that modifies neurotransmitters. No such drug exists for human use but certainly the search to find one, or make one, will continue.
Finally, basic research has yet to reveal the full biology of the lumbar cord and the manipulation of its apparent smartness. As this work continues it will enable more precise stim for more targeted tasks.
One last note: Rob Summers deserves a ton of kudos for his dedication and commitment. He gave up two years of his life for this work. Rob thinks it was worth it: “This procedure has completely changed my life. For someone who for four years was unable to even move a toe, to have the freedom and ability to stand on my own is the most amazing feeling. I believe that epidural stimulation will get me out of this chair."
By Sam Maddox
Learn more
