Spinal stimulation helps men with paraplegia walk again
03 November, 2018
A new way of electrically stimulating the spinal cord with wireless implants, together with therapy that supports body weight, has helped three men with paraplegia to walk again with the help of walking frames and crutches. They can even take a few steps without any aids at all.
Many years previously, the three men sustained injuries in the cervical area, or neck region, of their spinal cords that had left them paralyzed in their lower bodies.
The new "therapeutic framework" responsible for their rehabilitation is called Stimulation Movement Overground (STIMO).
It is the result of a collaboration between Ecole Polytechnique Fédérale de Lausanne (EPFL) and the Lausanne University Hospital (CHUV), both in Switzerland.
Two journals, Nature and Nature Neuroscience, have now published study papers about the new stimulation approach.
What is remarkable about the new method — and distinguishes it from two recently published studies from the United States on a similar topic — is that the men could move their legs when the electrical stimulation to the spinal cord was switched off.
In one of the study papers, the researchers explain the importance of "preserving proprioception" in order to restore movement control in humans with spinal cord injury.
The need to 'preserve proprioception'
Proprioception is somebody's ability to sense bodily position and movement by processing signals that come from their body itself, as opposed to its environment. Scientists often describe it as a "sixth sense."
Some who have written about it have cited the example of a man who, despite being able to make his muscles contract, was effectively immobile after an "infection deprived him of the sense of position, movement, and touch in his body" — or his proprioception.
The researchers in Switzerland maintain that if electrical stimulation of the spinal cord does not have the right combination of precise location targeting and timing of pulses, it can interfere with proprioception.
The STIMO method can overcome this by using "burst stimulation and spatiotemporal stimulation profiles." Using simulations, the researchers showed that it enabled "robust control over motor neuron activity."
"The exact timing and location of the electrical stimulation," explains co-author Jocelyne Bloch, a professor and neurosurgeon at CHUV, who carried out the implant surgery, "are crucial to a patient's ability to produce an intended movement."