The “surprising” clinical results, from the Walk Again Project, in Sao Paulo, Brazil, show patients have some sensations and muscle control in their legs. This is hopeful for people who need to regain strength and mobility after spinal-cord injuries or strokes.
Scientists, led by neuroscientist, Miguel Nicolelis, of Duke University in North Carolina, US, used a virtual reality system which harnessed the patients’ own brain activity to simulate control of their legs during the long-term training programme.
The first hopeful signs were spotted after seven months, but the sensations and muscle control reported by four patients were so strong after a year that doctors upgraded their diagnoses from ‘complete’ to ‘partial paralysis’.
Five participants had been paralysed for at least five years, while two had been paralysed for a decade. Most patients said they had better bladder control and bowel function and could cut back on laxatives and catheters. These changes reduce the risk of common infections and causes of death in people who have chronic paralysis.
Speaking as the findings were published in Scientific Reports, Mr Nicolelis said: “We couldn’t have predicted this surprising clinical outcome when we began the project. What we’re showing, in this paper, is that patients who used a brain-machine interface for a long period of time experienced improvements in motor behaviour, tactile sensations, and visceral functions below the level of the spinal cord injury.
“Until now, nobody has seen recovery of these functions in a patient so many years after being diagnosed with complete paralysis.”
The eight patients spent at least two hours a week using devices controlled through their brain signals. They were all taught how to operate their own avatar, or digital likeness, in a virtual reality environment. They wore fitted caps, lined with eleven non-invasive electrodes, to record their brain activity.
The patients were asked to imagine walking in the virtual world and “the training reinserted the representation of lower limbs into the patients’ brains”, said Mr Nicolelis.
More challenging physical equipment was later introduced to test patients’ control over their posture, balance, and ability to use upper limbs. These included walking devices and overhead harnesses.
A previous success of The Walk Again Project was Julian Pinto, a paraplegic who kicked a football during the 2014 World Cup opening ceremony by using a brain-controlled robotic exoskeleton. That exoskeleton was used by the other patients, also.
The progress of the patients, who have now had training for more than two years, will continue to be tracked by the researchers.