Paraplegic patients recovered partial control and feeling in their limbs after training to use a variety of brain-machine interface technologies

Brain-machine interface triggers recovery for paraplegic patients

The Walk Again Project, which researches brain-machine interfaces for paraplegic patients, has released its first clinical report.

During the 2014 FIFA World Cup opening ceremony a young Brazilian man who was paralyzed from the chest down delivered the opening kick-off. To pull off this amazing feat he used a brain-machine interface, allowing him to control the movements of a lower-limb robotic exoskeleton.

This unprecedented scientific demonstration was the work of the Walk Again Project (WAP), a non-profit, international research consortium.

In its first report, WAP showed how it followed eight patients paralysed by spinal cord injuries as they adapted to the use of the technologies, which convert brain activity into electric signals that power devices such as exoskeletons and robotic arms.

The patients also regained degrees of bladder and bowel control, and improved cardiovascular function, which in one case even resulted in a reduction in hypertension.

This is the first study to report that long-term brain-machine interface use could lead to significant recovery of neurological function in patients suffering from severe spinal cord injuries.

So far, the limits of this clinical recovery are unknown, since patients have continued to improve since the World Cup demo.

However, the researchers believe their initial findings could influence future clinical practices for paraplegic patients by upgrading brain-machine interfaces from a simple assistive technology to a potential new therapy for spinal cord injury rehabilitation.

"To our big surprise, what we noticed is that long-term training with brain-machine interfaces triggers a partial neurological recovery," said neuroscientist Dr. Miguel Nicolelis, director of the Duke University Center for Neuroengineering.

"What we didn't expect and what we observed is that some of these patients regained voluntary control of muscles in the legs below the level of the lesion and regained sensitivity below the level of the spinal cord injury.”

Alan Rudolph, vice president for research at Colorado State University, is passionate not only about the technological advances the new brain-machine interface represents, but also what it could mean for paralyzed patients.

"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," he said.

"The WAP scientists are making real impact in helping impaired people walk again. Seeing faces of young adults walking for the first time in many years has been life-changing for all of us."

Until now, no clinical study employing brain-machine interfaces in patients suffering severe spinal cord injuries reported any neurological improvements. Nicolelis believes this was due to the short-term nature of those studies, which usually involved only one human subject. In addition, none of these studies included detailed neurological evaluations to search for clinical improvement.

The brain-machine interface consisted of multiple EEG recording electrodes embedded in a cap on the patient's scalp, fitted over the brain areas controlling movement in the frontal lobe.

In a virtual reality component of the rehab protocol, the patients wearing an Oculus Rift head-mounted display were shown a three-dimensional avatar of a person, and were asked to imagine movements of their own bodies so they could make the avatar walk. All patients learned to use only their brain activity to move the avatar.

They received a continuous stream of tactile feedback, every time the avatar's feet touched the ground. This feedback was delivered through mechano-vibrating elements in a long-sleeved "tactile shirt."

The researchers believe that the training in effect rewired the circuitry in the brain, giving it new ways to communicate with parts of the injured body.

"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.

The WAP research was, in part, the inspiration for Rudolph to launch a virtual reality research initiative at CSU. Plans are in place for launching a virtual reality lab, and for a hack-a-thon in October.

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