Three paraplegics have walked for the first time in years after being fitted with a revolutionary new device.
Electrically stimulating the patients’ spinal cords helped them regain control of their legs after just one week.
Swiss researchers found surgically placing electrodes in the paralysed participants’ backbones activated signals that told their brains to walk.
These signals are thought to have triggered the growth of new nerve connections in the spinal cord of the patients.
Therefore, even after the electrodes were turned off, the patients were still able to walk up to a kilometre without tiring.
Following rehabilitation, the three patients could walk independently – either partially supported or with a walker.
The participants had electrodes implanted at specific points in their spinal cords.
‘The exact timing and location of the electrical stimulation are crucial to a patient’s ability to produce an intended movement,’ co-lead author Professor Grégoire Courtine, of The Ecole Polytechnique Fédérale de Lausanne, said.
‘The targeted stimulation must be as precise as a Swiss watch.
‘They have both recovered control of their paralysed muscles and I don’t think anyone with a chronic injury, one they’ve had for six or seven years, has been able to do that before.’
Placing the electrodes at different points in the vertebrae allowed the researchers to target varying groups of muscles in the legs.
These implants then activated signalling to the brain that allowed the patients to walk with the help of a body-weight support sling after just one week.
‘Our findings are based on a deep understanding of the underlying mechanisms which we gained through years of research on animal models,’ Professor Courtine said.
‘We were thus able to mimic in real time how the brain naturally activates the spinal cord.’
And as the study progressed, the patients’ control over their legs only got better.
‘Voluntary muscle control improved tremendously within five months of training,’ Professor Courtine said.
The participants were even able to walk more than a kilometre hands free with the help of a support sling.
Electrical stimulation is thought to cause the growth of new nerve connections in the brain.
Previous studies suggest this only helps patients walk when electrodes are turned on, with people then reverting to their paralysed state.
But due to the study’s participants experiencing no leg fatigue, they were able to take part in lengthy training sessions.
As a result, their brains had more time to ‘reorganise nerve fibres’.
This is thought to be what allowed them to walk even after the electrical stimulation was switched off.
‘The human nervous system responded even more profoundly to the treatment than we expected,’ Professor Courtine said.
HOW DOES THE ELECTRONIC IMPLANT WORK?
The Ecole Polytechnique Fédérale de Lausanne researchers connected 16 electrodes onto a pulse generator.
This device was then surgically implanted over the patients’ spinal cords in the regions that control their leg muscles.
Patients were given short, timed bursts of electrical stimulation.
At the same time, the patients were told to think about moving their legs.
This helped ‘activate’ dormant connections from their brains to their limbs.
The electrical stimulation is believed to have caused the patients to grow new nerve fibres.
This enables them, with continued use, to be able to walk even after the electrodes are ‘turned off’.
However, the patients can walk better when the stimulator is switched on.
The researchers therefore developed a voice-activated watch that controls the device and only responds to the specific patient.