Some injuries to human body tissues can heal and regain functionality after an injury. Muscle and bone tissue falls into this category. However, nerve tissue does not. Up until now traumatic nerve damage has been a permanent disability. One of the most seriously disabling instances of this is an injury to the spinal cord. That results in a loss of voluntary muscle control below the level of the break. People with the condition usually wind up in wheel chairs. Now there is news of a research break through that opens possibilities for some new approaches to the problem.
Voluntary movement shown in complete paralysis
Scientists, using epidural stimulation over the lumbar spinal cord, have enabled four completely paralyzed men to voluntarily move their legs.
Kent Stephenson is one of the four. This stimulation experiment wasn't supposed to work for him; he is what clinicians call an AIS A. This is a measure of disability, formally the American Spinal Injury Association Impairment Scale (AIS), that rates impairment from A (no motor or sensory function) to D (ability to walk). Kent, a mid-thoracic paraplegic, has what is considered a "complete" injury. Kent's doctors told him it was a waste of time to pursue any therapy; per the dogma, A's don't get better. Well, the young Texan, who was hurt five years ago on a dirt bike, didn't get the message. He likes to cite a fortune cookie he got shortly after his injury. It said, "Everything's impossible until somebody does it."
How does this work? The epidural stimulation supplies a continuous electrical current, at varying frequencies and intensities, to specific locations on the lower part of the spinal cord. A 16-electrode spinal cord stimulator, commonly used to treat pain, is implanted over the spinal cord at T11-L1, a location that corresponds to the complex neural networks that control movement of the hips, knees, ankles and feet.
The leg muscles are not stimulated directly. The epidural stimulation apparently awakens circuitry in the spinal cord. "In simple terms," says Dr. Angeli, "we are raising the excitability or gain of the spinal cord. Let's say you have an intent to move. That signal originates in the brain and gets through to the spinal cord but the cord is not aware enough or excited enough to do anything with that intent. When we add the stimulation, the spinal cord networks are made a little more aware, so when the intent comes through, the cord is able to interpret it and movement becomes voluntary."
Does this mean anyone with a spinal cord injury with an implanted stimulator can move? Not necessarily, says Dr. Harkema. "But what I want people to know about this study is that we need to change our attitude about what a complete injury is, challenge the dogma that in AIS A patients there is no possibility of recovery. The view is that it is not a worthwhile investment to offer even intense rehabilitation to people with complete injuries. They're not going to recover. But the message now is that there is a tremendous amount available. These individuals have potential for recoveries that will improve their health and quality of life. Now we have a fundamentally new strategy that can dramatically affect recovery of voluntary movement in those with complete paralysis, even years after injury."
There is a lot of other interesting neurological research going on that offers new possibilities for people with seriously disabling conditions. One is a cap that allows people to use their brain to control the activity of robots. Sound like science fiction? Well it is becoming reality.