The breakthrough achieved by a team of French-speaking neurologists and clinical experts (Professor Courtine and Bloch) is the latest achievement to understand and treat spinal cord injuries that force patients to stay in wheelchairs throughout their lives. Thanks to a combination of advanced technology that provides direct electrical stimulation to the spinal cord and intensive physical therapy, people with spinal cord injuries begin to walk.
What is different from the previous study?
Two recent studies have restored movement in patients who are paralyzed or partially paralyzed by applying continuous electrical stimulation to the spinal cord.
The new report from the prestigious journal Nature is the first demonstration of discontinuous stimulation: implants send targeted bursts of stimulation to the spinal cord which, in turn, stimulate the muscles intended to move. Indeed, stimuli can roughly mimic the signaling mechanism in the body.
Treatment is still experimental and its effectiveness for other patients with complete or partial paralysis remains to be determined. The three patients in the Swiss study felt a sensation in their feet before the start of the trial. They attended intensive training for months to take the difficult first step. They still rely on wheelchairs; two can go out using a walker.
Is electrical stimulation enough?
In all recent studies, complete and prolonged rehabilitation is very important for success. Participants attended 100 to 278 sessions that combined stimulation and rehabilitation for 5 to 21 months. So, electrical stimulation alone is not a "magic bullet".
How did the study begin?
The authors of the previous new report have shown that mice that have lost use of their hind legs can be trained to function again when continuous currents are applied to their muscles through the spinal cord.
However, in humans, continuous stimulation seems to send mixed signals to the muscles, activating some and confusing others. For this reason, bursts of electrical stimulation appear to be more successful in these three patients with milder spinal cord lesions.
What is the mechanism?
One interesting discovery is that each of the three patients learned to move the soft muscles before without the help of implants. Maybe electrical stimulation has caused nerves to be protected by injury to grow back.
What is the future?
More participants need to be tested and new stimulation techniques may be needed for various types of injuries. However, Professor Courtine's group at EPFL strengthens a bright future in treating spinal cord injuries.