"I want to emphasize that this work isn't just about me," Borgens said. "This always has been and always will be a team effort. I've just ended up being the spokesman for the group."

The device is implanted in the spine on both sides of an injured vertebra where nerves have been disconnected. The electrodes on either side of the injured section of the spine apply a DC field that stimulates the neurons to begin growing along the field direction.

Because neurons have an electrical polarization, when one end of the Neuron grows toward the field, the other end dies off. That posed a problem for the therapy because Motor and sensor neurons in the spinal cord are oriented in different directions. But one of Borgens' colleagues found that the die-off process only begins about an hour after the field is applied, while the new growth process starts immediately. So the problem was solved by reversing the field every 15 minutes. That activates only the growth process in both directions.

Another nice aspect of the therapy is that the nerves will easily grow through scar tissue and spontaneously link up.

Borgens and some of his colleagues had done biological studies of nerve Regeneration in animals. "There is a lot you can learn by studying animals that can regenerate their nerves," he said. Such animals "grow their neurons through scar tissue and make what we call inappropriate connections—never the right ones, never the ones that would have been established under normal development. What you find is that the brain can establish appropriate behavior through inappropriate connections.

'Incredibly plastic' brains
"Our brains and spinal cords are incredibly plastic, and therein lies the future for injured people," Borgens added. "We have to do some things to start the process, and I don't believe in a magic bullet. But this is a place to start, and our system is the only one out there right now that can do this."

Trials with the approach have shown that some rudimentary motor function can be restored to people with spinal cord injuries. The initial systems being developed by Cyberkinetics might be able to complement this therapy with connections between the brain and muscles that bypass the spinal cord. The combined approach might offer a breakthrough in helping paralyzed people regain control of their bodies.

Borgens said he doesn't expect to see people with spinal cord injuries restored to full function during his lifetime, but any return of functions is a wonderful development for patients.

"Getting up and walking isn't the most important thing to quadriplegics," he said. "Just being able to reach out, grasp a glass and raise it to their mouth is already an amazing capability for them."

- Chappell Brown
EE Times