Medical breakthrough helps chronic paraplegics walk again

A group of patients paralyzed by severe spinal cord injuries have regained the ability to voluntarily move their leg muscles and to feel touch and pain in their paralyzed limbs with the help of brain-controlled systems. Behind this medical breakthrough is the Walk Again Project (WAP), a non-profit international research consortium based in Sao Paulo, Brazil.

On June 12, 2014, WAP performed a unique scientific demonstration, during the opening ceremony of the Soccer World Cup in Brazil. During that demo, a young Brazilian man paralyzed from his chest down, delivered the opening kickoff of the World Cup by using a brain-machine interface (BMI) that allowed him to control the movements of a lower-limb robotic exoskeleton, while receiving tactile feedback from the exo’s feet.

Two years after its public demonstration, WAP published its first clinical report, describing the findings obtained after the first year of training of the eight paraplegic patients, from January to December 2014.In this clinical study, the international team of neuroscientists, engineers, and neurorehabilitation personnel reports the discovery that the group of patients who have continued to train with the BMIs – despite being originally diagnosed as having a clinically complete spinal cord injury, in some cases more than a decade earlier – recovered the ability to move their legs, regained important degrees of bladder and bowel control, and improved their cardiovascular function, which in one case resulted in a significant reduction in hypertension.

As such, this is the first study to report that long-term BMI use may lead to significant recovery of neurological functions in patients suffering from severe spinal cord injuries.

The WAP researchers theorize that the long-term training regimen, which started in the early part of 2014, likely promoted brain reorganization and activated dormant nerves that may have survived the original spinal injury that occurred 3-14 years earlier.

The team, led by neuroscientist Miguel Nicolelis, director of the Duke University Center for Neuroengineering and principal investigator of the WAP, trained eight paraplegic patients over a period of a year on what the scientists named the Walk Again Neurorehabilitation protocol. They have been completely paralyzed for 3 to 13 years due to a severe spinal cord injury. Seven had been classified as having a complete injuryand one had been classified as an incomplete injury. 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 study used a BMI that 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. The patients learned to use only their brain activities to control the walking movements of a 3D avatar while wearing an Oculus Rift head-mounted display.

They also used a Lokomat, a robotic gait orthosis, placed on a treadmill, which enables paraplegics to perform walking motions while suspended by a harness. The third training component is a brain-controlled motorized exoskeleton custom designed for the project by an international team of roboticists.

In all three components, the patients received tactile feedback delivered to the skin of their forearm to ensure full tactile sensitivity.The combination of visual and haptic feedback was critical to the training paradigm, said Nicolelis. “The addition of tactile feedback that was coherent with the visual feedback created a very realistic walking illusion for the patients when they controlled a virtual avatar or the robotic exoskeleton”.

As an overall result of the 12 months of training, four of the eight patients who were classified as “completely paralyzed” were upgraded to “incomplete paraplegia”. The researchers also found that the patients’ gastrointestinal function improved, with the number of bowel movements directly correlated with the hours of upright walking.

Nicolelis said they hope to take this protocol to other spinal cord centers worldwide to try and replicate their findings.

“Currently, once people with spinal injuries receive a diagnosis of complete paralysis, rehabilitation consists mainly of adapting them to a wheelchair. We believe that our results with this long-term, sustained brain-machine interface training can be not only critical itself in triggering recovery in our patients, but it can also serve as an important motivator for spinal cord patients worldwide,” he added.

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