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. New research published in the medical journal Brain documents the effectiveness of epidural stimulation as a therapy option for chronic motor complete spinal cord injuries.
In the case of this research, epidural stimulation is the application of a continuous electrical current, at varying frequencies and intensities, to specific locations on the lower part (lumbosacral) of the spinal cord. A 16-electrode epidural spinal cord stimulator, commonly used in medicine today to treat pain, was surgically implanted over the spinal cord at T11-L1. This location corresponds to dense neural networks that control movement of the hips, knees, ankles and feet.
The stimulation from the implanted device mimics the signals normally transmitted by the brain. This restored stimulation then re-engages the spinal cord with its neural network below the point of injury.
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.
Epidural stimulation represents a breakthrough in the scientific and clinical understanding of control of movement and the possibilities for the most severely injured. Rob Summers, who had a severe spinal cord injury received the implant in 2009 and began the experimental training that accompanied it. Today, three other individuals who have undergone the treatment are experiencing similar, unexpected yet significant results.
The research team reports that three individuals were able to make voluntary movements when epidural stimulation was turned on; results were seen immediately after implant -- even in two who were diagnosed with a motor and sensory complete lesion.
Before this research study, functional electrical stimulation has been used to activate paralyzed muscles in people with spinal cord injuries.
But these new neuromodulation studies are not about stimulating muscle. In this new research, epidural stimulation activates nerve circuits in the spinal cord, substituting for nerve signals that would normally have come from the brain to modulate these spinal networks. Stimulation of the spinal circuitry itself activates what scientists call a central pattern generator -- a network of nerves that are able to initiate stepping function without input from the brain.
“We don’t have to necessarily rely on regrowth of nerves in order to regain function. The fact that we’ve observed this in four out of four people suggests that this is actually a common phenomenon in those diagnosed with complete paralysis,” said Dr. Reggie Edgerton, who has been conducting fundamental research in this area for 38 years and is a member of the Reeve Foundation’s International Research Consortium on Spinal Cord Injury.
To learn more, read published article, “Altering spinal cord excitability enables voluntary movements after chronic complete paralysis in humans” in Brain, A Journal of Neurology, April 8th, 2014 Read Article
Or visit: Christopher & Dana Reeve Foundation