None of the patients had shown any clinical improvement with traditional rehabilitation prior to enrolling in the WAP and all eight showed no movement below the level of their spinal cord injury. The researchers could then generate a specific set of commands for the exoskeleton based on the activity of an individual patient’s brain, while the patient practised finessing the sort of control they would need for the exoskeleton.
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The study, the results of 12 months of training, is the first long-term BCI experiment to show significant recovery from such severe injuries, the researchers say.
A 32 year-old female patient paralysed for 13 years experienced the most dramatic changes, according to Nicolelis.
The system also makes use of a virtual reality environment that enables the user to practice moving an avatar as they imagine walking.
Within 13 months, she could walk with the help of braces and a therapist, and could produce a walking motion while suspended from a harness.
It was hoped that the newfound control could control the robotic legs, but progress was so rapid that 4 of the 8 patients were upgraded to partial paraplegia.
The study was released in Thursday’s Scientific Reports.
Dr Miguel Nicolelis, director of the Duke University Centre for Neuroengineering in the USA, said previously seven patients were classified as having total paralysis, but had now been upgraded to “partial paralysis”. “We haven’t seen a plateau for recovery yet”. The team first made headlines in 2014 during a demonstration at the soccer World Cup in Brazil, where a patient wearing a special brain-controlled exoskeleton suit was able to kick a soccer ball to open the competition.
At that point, the patients moved on to more challenging exercises using equipment that allowed them to move their own bodies, rather than a virtual avatar. In few months of brain-training they have been able to move and get a response from muscles that have been idle for a decade.
The brain-machine interface used in this study consisted of multiple EEG recording electrodes embedded in a cap on the patients’ scalp, fitted over the brain areas controlling movement in the frontal lobe. Haptics use varied vibrations to offer tactile feedback, much like the buzzing jolts or kickbacks gamers feel through a handheld controller.
And earlier this year, a USA man paralysed in the arms was able to use his right hand to swipe a credit card and stir coffee thanks to a surgically-inserted chip that allowed his brain to communicate with computer linked to an electrode sleeve.
“Linking brains to machines directly and providing feedback, we may have created a potential rehab therapy”, said Dr. Miguel Nicolelis, co-author of the study and the founder of the Center for Neuroengineering at Duke University and Duke School of Medicine professor in neuroscience. Patients also regained some degree of bladder and bowel control, as well as improved cardiovascular function.
Nicolelis said in many traumatic spinal cord injuries, a small percentage of nerves can remain, but after years without brain signals, the nerves go dormant. A research was conducted on eight paraplegic patients, who were paralyzed for years. “All patients learned to use only their brain activity to move the avatar”.
“Over time, training with the brain-machine interface could have rekindled these nerves”, Nicolelis said.
“This has been a tremendous journey, to start working on this phenomenal project over 15 years ago on ideas first demonstrated in animals, and that are now showing revolutionary theories of how the brain works”, Rudolph said.
“We may actually have triggered a plastic reorganization in the cortex by re-inserting a representation of lower limbs and locomotion in the cortex”, Nicolelis said.
“It is very promising to see research which takes steps into returning function and sensation to spinal cord injured people”, she added.
But those with spinal cord injuries end up with disrupted signals between brain and legs.
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Almost all of the patients described in the study have continued their rehabilitation, now exceeding two years of training, Nicolelis said.
