A team in Switerland have developed implants that allow patients who have suffered spinal injuries to walk again. École Polytechnique Fédérale de Lausanne (EPFL) have partially restored movement to David M’zee, 30, who can walk with the assistance of a frame, following a severe spinal injury sustained 7 years ago in a sporting accident. Perhaps more notably, for the first time in a chronic spinal injury, the patient is able to walk with the implant turned off (albeit only for 8 paces.)
The treatment works through elecrode array implants in the spine, connected to a pulse generator that sends electrical signals. Patients can activate the technology with the use of a watch that responds to voice commands.
Dr. Courtine, an author of the study, expressed some surprise at the outcome. “What we observed in animals is that it seems that the nerve fibres are regrowing and reconnecting the brain to the spinal cord,” he said. Whilst the technology works by amplifying signals from the brain to the spine, this is an unexpected benefit.
The news comes as two separate teams in the USA were able to use continuous electrical stimulation to allow patients to regain some movement, a month earlier. In that earlier study, researchers also relied on the intergration of several electrodes, into the lower back, alongside locomotor training (repeatedly practicing exercises like sitting and standing with body-weight-support.) Two out of four patients were able to walk, whilst the others were able to sit independently and make stepping motions on a treadmill. Out of those two patients that were able to walk again, Jeff Marquis, who had undergone 278 sessions over 85 weeks was able to walk 90 metres, without the use of a frame, whlst Kelly Thomas was also able to walk, with the assistance of a frame.
However, unlike in the more recent study, the patients were unable to walk with the electrical pulses turned off, but this is possibly because continuous stimulation is not as effective at growing new nerve connections, compared to this more targeted therapy, activating the necessary leg muscles in precisely the right order.
Both treatments are based on epidural electrical stimulation, which has been investigated as a potential treatment for paralysis for decades, using electrical stimuli, to allow patients to regain motor function.
Researchers studied the underlying mechanisms of EES, enabling the brain to exploit spared but functionally silent descending pathways (direct communication between neurons in the brainstem nuclei and spinal cord for automatic movements, such as postural control.) According to a study published in the journal Nature, scientists were able to “improve the ability of the spinal cord to translate task-specific sensory information into the muscle activity that underlies standing and walking.”
Scientists believe that the use of this emerging technology, alongside traditional methods of rehabilitation can help to heal the nervous system around an injury.
Whilst the rudimentary treatment is not a cure for paralysis, and patients cannot walk nearly as well as they were able to, before sustaining trauma, these studies serve as an important first step in the treatment if an illness that was once considered incurable.
Photo Credits due to: https://www.gizmodo.com.au/2012/09/spinal-stem-cell-injections-help-reverse-paralysis/