May 20, 2011 — Continual direct epidural stimulation of the spinal cord and extensive task-specific locomotor training enabled a young man paralyzed below the waist to stand up from his wheelchair and bear his full weight with assistance provided only for balance.
With continuous epidural stimulation, the patient, Rob Summers, now 25 years old, also took a few assisted steps on a treadmill and has recovered some voluntary leg movement.
This approach, tested extensively in animal models of spinal cord injury, "might reactivate previously silent spared neural circuits or promote plasticity," investigators say in their report published online May 20 in The Lancet.
The 11-member research team was led by neuroscientists Susan Harkema, PhD, of the Kentucky Spinal Cord Research Center, University of Louisville, and V. Reggie Edgerton, PhD, of the David Geffen School of Medicine at University of California, Los Angeles.
"These interventions could be a viable clinical approach for functional recovery after severe paralysis," they conclude.
Achievement 'Unprecedented'
In a linked Comment, 3 neurorehabilitation experts say the level of functional recovery in this paraplegic patient "remains unprecedented in SCI [spinal cord injury] medicine."
"We think that this novel phenomenon of electrically enabled motor control will inspire new thinking in the future design of strategies to restore function in motor-impaired individuals," write Grégoire Courtine, PhD, and Rubia van den Brand, PhD, of University of Zurich, Switzerland, and Pavel Musienko, PhD, of Pavlov Institute of Physiology, St Petersburg, Russia.
The patient had paraplegia from the C7-T1 subluxation as a result of a motor vehicle crash in July 2006. He had complete loss of clinically detectable voluntary motor function but did have some feeling below the level of injury (T1 cord segment), giving him a "B" rating on the American Spinal Injury Association's classification system.
Before implantation of the electrical stimulation device, the patient had no residual supraspinal control of leg movements, despite roughly 2 years of intense locomotor training. In December 2009, the 16-electrode array was surgically implanted on the dura (L1-S1 cord segments) to permit long-term electrical stimulation.
In the first weeks after surgery, epidural stimulation enabled the man to stand for a few minutes, bearing his own weight. Optimizing epidural stimulation parameters for movement elicited assisted stepping-like patterns on a treadmill. After several months, the patient regained the "striking capacity" to consciously control joint-specific movements of the leg, but only during epidural stimulation, the authors of the Comment note.
The study authors provide videos that document Mr. Summers' recovery:
It shows that epidural stimulation "modulates the physiological state of the spinal circuitry to enable sensory information to become a source of control of movement in the absence of supraspinal input."
"The spinal cord is smart," Dr. Edgerton added in a statement. "The neural networks in the lumbosacral spinal cord are capable of initiating full weight bearing and relatively coordinated stepping without any input from the brain. This is possible, in part, due to information that is sent back from the legs directly to the spinal cord."
'Long Road Ahead'
Dr. Harkema and colleagues hope their work will eventually allow at least some individuals with complete spinal cord injuries to use a portable stimulation unit and, with the assistance of a walker, stand independently, maintain balance, and take steps.
"But we have a long road ahead," Dr. Harkema said.
Susan Howley, executive vice president for research at the Christopher & Dana Reeve Foundation, which helped fund the research, said, "Today's announcement clearly demonstrates proof of concept. It's an exciting development. Where it leads to from here is fundamentally a matter of time and money."
In their Comment, Dr. Courtine and coauthors emphasize that these results need to be replicated in other patients. Still, they say the "exceptional results" in this single patient bring "new hope in a field that has remained unsatisfying — with limited progress despite decades of research throughout the world. We are entering a new era when the time has come for spinal cord injured people to move."
The study was funded by the US National Institutes of Health and Christopher & Dana Reeve Foundation.
Lancet. Published online May 20, 2011. Abstract
With continuous epidural stimulation, the patient, Rob Summers, now 25 years old, also took a few assisted steps on a treadmill and has recovered some voluntary leg movement.
This approach, tested extensively in animal models of spinal cord injury, "might reactivate previously silent spared neural circuits or promote plasticity," investigators say in their report published online May 20 in The Lancet.
The 11-member research team was led by neuroscientists Susan Harkema, PhD, of the Kentucky Spinal Cord Research Center, University of Louisville, and V. Reggie Edgerton, PhD, of the David Geffen School of Medicine at University of California, Los Angeles.
"These interventions could be a viable clinical approach for functional recovery after severe paralysis," they conclude.
Achievement 'Unprecedented'
In a linked Comment, 3 neurorehabilitation experts say the level of functional recovery in this paraplegic patient "remains unprecedented in SCI [spinal cord injury] medicine."
 |
| Rob Summers before the motor vehicle crash. |
The patient had paraplegia from the C7-T1 subluxation as a result of a motor vehicle crash in July 2006. He had complete loss of clinically detectable voluntary motor function but did have some feeling below the level of injury (T1 cord segment), giving him a "B" rating on the American Spinal Injury Association's classification system.
Before implantation of the electrical stimulation device, the patient had no residual supraspinal control of leg movements, despite roughly 2 years of intense locomotor training. In December 2009, the 16-electrode array was surgically implanted on the dura (L1-S1 cord segments) to permit long-term electrical stimulation.
In the first weeks after surgery, epidural stimulation enabled the man to stand for a few minutes, bearing his own weight. Optimizing epidural stimulation parameters for movement elicited assisted stepping-like patterns on a treadmill. After several months, the patient regained the "striking capacity" to consciously control joint-specific movements of the leg, but only during epidural stimulation, the authors of the Comment note.
The study authors provide videos that document Mr. Summers' recovery:
- Sit to stand with caudal stimulation (7.5 V, 15 Hz);
- Full weight-bearing standing with epidural stimulation (9 V, 25 Hz) without manual facilitation;
- Attempts at voluntary movements (leg, ankle, and toe) with epidural stimulation (4 V, 30 Hz) in the supine position; and
- Attempts at voluntary movements (leg, ankle, and toe) without epidural stimulation in the supine position.
For someone who for 4 years was unable to even move a toe, to have the freedom and ability to stand on my own is the most amazing feeling.
In their Comment, Dr. Courtine and colleagues note that the "unexpected recovery of supraspinally mediated improvement suggests that activity-dependent mechanisms prompted plasticity of axonal projections that presumably were spared by the injury."It shows that epidural stimulation "modulates the physiological state of the spinal circuitry to enable sensory information to become a source of control of movement in the absence of supraspinal input."
"The spinal cord is smart," Dr. Edgerton added in a statement. "The neural networks in the lumbosacral spinal cord are capable of initiating full weight bearing and relatively coordinated stepping without any input from the brain. This is possible, in part, due to information that is sent back from the legs directly to the spinal cord."
'Long Road Ahead'
 |
| Rob Summers on the treadmill. |
"But we have a long road ahead," Dr. Harkema said.
Susan Howley, executive vice president for research at the Christopher & Dana Reeve Foundation, which helped fund the research, said, "Today's announcement clearly demonstrates proof of concept. It's an exciting development. Where it leads to from here is fundamentally a matter of time and money."
In their Comment, Dr. Courtine and coauthors emphasize that these results need to be replicated in other patients. Still, they say the "exceptional results" in this single patient bring "new hope in a field that has remained unsatisfying — with limited progress despite decades of research throughout the world. We are entering a new era when the time has come for spinal cord injured people to move."
The study was funded by the US National Institutes of Health and Christopher & Dana Reeve Foundation.
Lancet. Published online May 20, 2011. Abstract
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