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A Second Chance

Written by Science, Science & Tech

Three patients with paraplegia – an impairment in function of the lower extremities – have successfully undergone a novel treatment that has seen them regain the ability to walk again after devastating spinal injuries. This is the result of two separate studies which, together with physical therapy, incorporated a device to electrically stimulate the spinal cord.

Dr Claudia Angeli, of Kentucky Spinal Cord Injury Research Centre at the University of Louisville, and a co-author of one of the studies, expressed her delight at the findings. “It is incredible to be able to be in there and actually see them taking their first steps” she told The Guardian.

The study, published in the New England Journal of Medicine, details the procedure in which an array of 16 electrodes were implanted in the lower backs of four patients who were the victims of mountain bike or traffic accidents.

The device was initially developed for pain control and was placed below the site of injury, covering regions that send neuronal signals to the legs. A battery was implanted in the abdomen, allowing the frequency of the stimulation, its intensity and duration, to be tweaked wirelessly. Electrical activity produced by muscles in the legs was monitored during the sessions.

This technique – called epidural stimulation – works on the principle that there are still some signals that are conducted to the legs, despite the spinal injury. These signals, while not enough to generate voluntary movement, could be used to drive epidural stimulation. “We know the spinal cord has the ability to organise very detailed motor activity,” said Angeli. “But before the injury it was getting commands from the brain and it was getting information from the environment as well.” The injury, she hypothesised, disturbs this by disrupting the signal from the brain.

However, by stimulating the nerves using electricity, Angeli says it can help in regeneration of lost neural signals. “It is like it (the spinal cord) is more aware, it actually can listen to that little whisper from the brain that it is still there and it can generate the motor pattern,” said Angeli. She added that linking these signals to movement must be done through training.

Kelly Thomas, one of the participants of the study, was able to walk after 81 sessions of stimulation over 15 weeks, although she had to use a walking frame. She said, “Being a participant in this study truly changed my life, as it has provided me with a hope that I didn’t think was possible after my car accident.

A separate paper by researchers from the Mayo clinic in Minnesota and UCLA, published in the journal Nature Medicine, also reports success with the same approach. “The patient’s own mind, or thought, was able to drive the movement in the legs,” said Dr Kendall Lee of the Mayo Clinic, one of the principal investigators of the study. But he was also cautious about the approach, “You have to deliver a very specific type of stimulation parameters. A random stimulation does not work.”

Their next focus, according to Angeli, will be to achieve more control of leg movement as well as to try and get bladder control – a common problem in patients affected by paraplegia.

There are, however, other potential solutions being explored by various organisations. Prof Grégoire Courtine from the EPFL research institute in Switzerland is looking at trying to increase the synchronisation between the signals and the movement itself, while the Nicholls Spinal Injury Foundation, which prefers a natural solution, is working on using the nasal cells in conjunction with nerve fibres to regenerate lost spinal cord cells, and has achieved some success with this.

Last modified: 19th November 2018

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