Hope for the paralyzed from new method of electric stimulation
Scientists in Saint Petersburg and Zurich are hoping to help paralyzed people by using electric stimulation and implants. They have already tested the new method on rats and are preparing for the first trials involving disabled human patients.
“The idea of using electric stimulation resulted from many years of experiments," said Pavel Musiyenko, one of the new method's developers. He works for the Institute of Translational Biomedicine at the St. Petersburg State University. "Earlier, electric stimulation was used in tonic mode, i.e. with one or two areas of the spinal cord stimulated nonstop.”
He said during the course of tests on rats, the scientists developed electrode matrixes, new implant technologies, and an algorithm of alternate stimulation of different zones of the spinal cord, depending on the task at hand and the condition of the animals’ locomotor system.
Hope for paralyzed cats?
The research group, led by Swiss scientist Grégoire Courtine, created a new algorithm to stimulate nerve fibres, allowing paralyzed laboratory rats to move again. The scientists established that some nerve endings remain unaffected even in very serious injuries.
They reprogrammed the unaffected neural connections in the spinal cord for new activity, like restoring lost locomotor activity. Electric stimulation of these neurons, and special training in an exoskeleton, designed specially for this purpose, yielded positive results, with the rats restoring their locomotor activity practically to full strength.
“The underlying principle is that if the ability to flex the back is affected, then it is the zone that is responsible for flexor muscles that needs to be stimulated, and the same applies to zones responsible for extensor muscles," explained Musiyenko. "The method works, but I think it is premature to say that it should be tested on humans straight away."
According to Musiyenko, the new approach should first be tested on larger mammals such as cats, or possibly monkeys.
Humans must wait
Time is one obstacle to rehabilitation. The method does not work if paralysis happened years ago, or in cases of partial paralysis. But it is applicable at early stages of treatment. Special electro-stimulation ‘matrixes’, i.e. stem cell-based implants, make it possible to activate unaffected nerve cells and circuits in the process of restoring locomotor activity.
“It is not yet clear when tests on other animals will begin. That depends on funding and the research team," said Musiyenko. "Neurophysiologists, neurosurgeons, engineers and other experts are just as essential for a successful test and technology implementation as the financial investment."
Meanwhile, Swiss and Russian scientists continue to study the mechanisms of restoring the spinal cord through electric stimulation. They are currently developing rehabilitation methods for patients with partial paralysis.