Published: Fri, November 02, 2018
Science | By

'Electrical stimulation helps three paralysed patients walk again'

'Electrical stimulation helps three paralysed patients walk again'

"It's an wonderful feeling", says David Mzee, whose left leg was paralyzed in 2010.

They can do so with only the aid of crutches or a walker, thanks to incredibly precise electrical stimulation of their spinal cord combined with intensive rehabilitation, the scientists said. The results of the experiment were published in the latest issue of the journal Nature and an accompanying article was published in the Nature Neuroscience.

While the results were astonishing, the team was quick to caution that the treatment - called epidural electrical stimulation - is in the early stages and it is not clear for how many people this would work. When it's on, he's able to walk more than half a mile.

The difference lies in how constant the electrical stimulation is. EES works by implanting a device that delivers electrical signals to the spinal cord.

No spinal cord injury is the same, and treating complete injuries - where there is no connection left between the brain and the spinal cord - will require a combination of techniques, Dr Gustin said. Physiological differences between humans and rats-including just the difference in body size-could explain why this affects humans and not rats, they suggest.

"If we can stimulate the central nervous system and peripheral nervous system at the same time, the additive effects could restart touch perception and movement in some people".

Nerves in the spinal cord send signals from the brain to the legs. They even built personalized model spinal cords to lie in an electricity-conducting salty fluid, allowing the team to work out precisely where each electrode needed to be inserted during surgery. Then the pattern of electrical signals was calibrated for each individual. Within a week, the men could stand up and walk using supports. In ongoing tests of the system, the patients were able to adjust the length and speed of their strides and to walk on a treadmill for an hour-traveling the equivalent of up to one kilometer. The researchers administered the EES in bursts that were controlled wirelessly.

"The participants are constantly challenged to voluntarily generate the appropriate leg movements", says co-author Karen Minassian. Walking actually came in fourth, behind sexual function, bladder and bowel movement, and the ability to control body posture. With EES switched on, he's able to walk using a walker.

Gert-Jan Oskam, who lost the use of both his legs in a cycling accident, had also made very limited progress in rehabilitation before the study. However, there is a special thanks to the team at Ecole Polytechnique Federale de Lausanne who had developed an electrical implant due to which David managed to walk nearly more than half a mile continuously. I'm surprised at what we have been able to do.

"Voluntary muscle control improved tremendously within five months of training", said Courtine. He plans to continue training.

An unfortunate result of spinal cord injuries is that nervous system communication can become severely disrupted, resulting in the loss of neurological functions and ultimately, paralysis.

All patients involved in the study recovered voluntary control of leg muscles that had been paralysed for many years, they said.

And essential, they add, is ensuring that the treatment translates outside of the hospital.

When the stimulation was fed in pulses that worked in conjunction with the proprioceptive system, patients achieved remarkable improvement in their ability to move previously paralyzed legs in coordination, the researchers said. 'And [Tobler] needs a walker.' Courtine built a mobile app that allows the patients to turn their stimulators on or off remotely, so they could train at home after the study ended.

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