In a world first, a team of researchers at the University of California Los Angeles have restored movement and control to the hands and fingers of six people with severe spinal cord injuries after only four weeks of training with the group’s non-invasive spinal stimulation system.
Prior to their inclusion in the study, published in the Journal of Neurotrauma, three participants had suffered from partial paralysis that significantly affected their hand movement, and three had been completely paralyzed for at least one year and up to 21 years, following injuries to their cervical spinal cords.
Then, the six lucked into spots as testers for senior author and laboratory leader V. Reggie Edgerton’s experimental nerve retraining procedure called transcutaneous enabling motor control, or tEmc.
During each session, participants attempted to squeeze a spring-loaded device and hold their grip for several seconds while electrodes placed at strategic points on the skin of the neck delivered an electrical current of varying intensity and frequency to clusters of neurons below.
“After just eight sessions, they could do things they haven’t been able to do for years,” Edgerton said in a statement. In addition to hand grip, several patients regained some movement in their legs, the ability to sit up without support, and showed improved bladder and cardiovascular function.
The work builds upon the recent revelations, uncovered by Edgerton and his current and former colleagues, that neural connections between the muscles and the spinal cord remain intact following years of inactivity due to partial or even complete spinal cord injuries. Thanks to the inherent plasticity of nerve cells, they may be modulated to transmit signals once again.
In 2014, Edgerton’s lab and the University of Louisville restored voluntary motor control to the legs of four men who had been completely paralyzed in their lower extremities for at least years. They did this using a device that continuously stimulates the spinal cord through a network of implanted electrodes – another world first at the time.
Believing that a non-surgical intervention could accomplish the same results, the team developed the tEmc system, then called transcutaneous electrical spinal cord stimulation. A successful test in five more men with complete leg paralysis proved their hypothesis in 2015
Dr Parag Gad, lead author on the current study and contributor to the 2015 work, explained to IFLScience that tEmc works by first activating dormant neural networks, which in turn activate the appropriate muscle groups to improve limb function. Over time, this establishes bidirectional communication between the brain and the muscles, eventually allowing “the patient to maintain the function even when the stimulation is turned off.”
In the past few years, many other research groups have also succeeded in restoring movement to partially and completely paralyzed individuals, yet their approaches still rely on some sort of surgically implanted device.
A system that restores movement without the need for an invasive procedure and an implant that will likely need replacement over the years is, therefore, quite a game-changer.
“I get criticized a lot for giving ‘false hope’ but we follow where the science tells us to go and just give the research results,” Edgerton said. “Everything is telling us the nervous system is much more adaptable than we’ve given it credit for, and can relearn and recover from severe injury.”
The long-term outcomes following tEmc therapy are unknown at this time.