Rob Summers can stand with the aid of a spinal cord stimulator. Photo courtesy of Rob Summers.
25-year-old Rob Summers, who was paralyzed below the chest in a car accident in 2006, can now stand for several minutes on his own thanks to an experimental treatment designed to stimulate the spinal cord. With help, he can also take repeated steps on a treadmill and voluntarily move his hips, knees, ankles, and toes, and he has regained some sexual and bladder function, according to research published today in the journal the Lancet. Researchers say the advance is a breakthrough in the treatment of spinal cord injury, though they caution that it has only been tested in one patient.
Video: Summers sit to stand with caudal stimulation.
The therapy consisted of a stimulator device originally designed to treat chronic pain, which was implanted near the spinal cord. According to a report in the Los Angeles Times,
The treatment, devised primarily by UCLA neurobiologist V. Reggie Edgerton, is designed to activate a patient’s spinal nerves just enough to make them responsive to sensory signals coming from the legs. The approach, which Edgerton has been using in animals for nearly three decades, is like using a hearing aid to amplify sound.
“To everyone’s disbelief, I was able to stand independently the third day we turned it on,” said Summers, who was a baseball player in his junior year at Oregon State University in Corvallis at the time of his accident. He completely supported himself, but needed some help with balance.
The important thing, Edgerton noted, is that the device did not cause Summers to stand, as previous attempts at electrical stimulation have done. When Summers is sitting normally with the stimulus operating, nothing happens. But when he leans forward and puts some weight on the legs, muscle memory takes over and the spine sends signals to the legs that cause him to stand.
According to a press release from the journal, the stimulation mimics signals that the brain normally sends the spinal cord to initiate movement.
Once that signal is given, the research shows, the spinal cord’s own neural network combined with the sensory input derived from the legs to the spinal cord is able to direct the muscle and joint movements required to stand and step with assistance on a treadmill. The other vital aspect to the work was having the individual’s spinal cord neural networks retrained to produce the muscle movements necessary to stand and to take assisted steps. This training work took more than 2 years to complete, after which the electrostimulation device was surgically implanted in the patient’s back. Before the device was implanted, the patient had no voluntary control.
Video: Full weight-bearing standing with epidural stimulation without manual faciliation.
The authors, Susan Harkema, of the Kentucky Spinal Cord Research Center at the University of Louisville, Kentucky, and Reggie Edgerton, at the University of California, Los Angeles, “hope their work will enable 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 execute some effective stepping. But they also caution much more work needs to be done before this technique could become standard practice,” according to the release.
Before the treatment, the patient did have some sensation below the chest, so it’s not clear whether the treatment will work on those who report no sensation below the injury.
Video: Voluntary movements (leg, ankle, and toe) with epidural stimulation in the supine position.
“This procedure has completely changed my life,” said Summers in a statement. “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. To be able to pick up my foot and step down again was unbelievable, but beyond all of that my sense of well-being has changed. My physique and muscle tone has improved greatly, so much that most people don’t even believe I am paralyzed. I believe that epidural stimulation will get me out of this chair.”
All videos courtesy of the Lancet.