Developing a Cure to Paralysis:
Helping paralyzed patients regain motion:
Dr. Milos Popovic used to build control systems for airplanes. Today, he’s building systems to help some people who are paralyzed learn to move again after a stroke or spinal cord injury.
A Scientist at Toronto Rehab and head of the Rehabilitation Engineering Laboratory, Dr. Popovic’s main research focus is to understand how the human nervous system and muscles work together to control body movement. “Based on that knowledge, I propose different means of recovery after stroke or spinal cord injury,” he says.
Dr. Popovic’s research is part of an exciting new discipline known as neuroprosthetic systems - designing devices that help to restore or replace functions of the human nervous system when it is damaged. The oldest and best-known neuroprosthetic device is probably the cardiac pacemaker, which helps damaged hearts beat at a healthy rate.
In some cases, these devices have the potential to not only replace lost function but to help people regain at least some normal function by “retraining” their nervous systems.
"It’s a phenomenal intellectual challenge - a couple of orders of magnitude more challenging than any previous engineering problems I’ve faced," says Dr. Popovic, who worked in robotics and aerospace design and control systems before coming to his current field.
"There are many uncertainties. We don’t fully understand how the human system works at this point. Any individual cell is much more complex than the space shuttle. Now, imagine how many cells you have, and consider that they all have separate functions and trigger all sorts of different mechanisms. You begin to realize the stunning level of complexity we are dealing with."
At the moment, Dr. Popovic is studying a procedure called FES, or functional electrical stimulation. In FES, a Walkman-sized device is used to stimulate the patient’s nerves with electrical impulses. Stimulating the correct nerves in the correct order generates different actions such as opening hands or walking. Feedback from the action goes to the brain. By repeating these simple tasks over and over, some patients ‘re-train’ their nervous systems and learn to carry out the movements by themselves, without using the FES device.
While it’s too soon to say how well it works, early results are encouraging. Small-scale pilot studies showed FES helped some patients with incomplete spinal cord injuries or stroke learn to pick up and hold objects. Large-scale studies, now underway, will show conclusively whether or not the technique is effective.
Dr. Popovic finds his work highly rewarding, especially when he sees patients regain use of their hands and legs. “I especially remember one stroke patient, an older man who was in really bad shape when he was admitted. He was very committed to working with us and, after eight weeks of treatment, he regained the use of his arm. It made a huge difference to his life.”