Mind-Controlled Exoskeletons Help Paraplegics Regain Control of their Limbs

One of the more positive aspects of the development of brain-machine interfaces — the technology of linking mind and mechanism — is the promise of allowing paralyzed individuals to regain their mobility through controlling machines via their thoughts. While there has been a great deal of progress in this field over the last few years, one program appears to have had an unexpected effect on the subjects involved, where the individuals were able to regain sensation in, and control of, their paralyzed limbs after learning to use the equipment.

The Walk Again Project, conducted by researchers from Duke University, utilizes robotic exoskeletons and virtual reality that are controlled by the subjects’ thought patterns, seeking to develop new methods for paraplegic individuals to regain their mobility through these devices. But something happened in eight of the subjects that were involved in the program that was completely unexpected: they began to regain sensation and muscle control in their legs.

"We couldn’t have predicted this surprising clinical outcome when we began the project," exclaims study lead and neuroscientist Miguel Nicolelis. "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 behavior, 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."

Since neural patterns vary from person to person, the subjects trained themselves to control the apparatus through first learning to mentally control a virtual avatar of themselves using virtual reality, a process that also provided data for the researchers to tailor the equipment controls for each subject. Once the subjects had mastered control their virtual selves, they graduated to the physical exoskeleton.

The process required the subjects to make use of their arms, posture and balance to operate the exoskeletons, prompting an effect where nerves that were dormant after the patient’s injury to be reactivated and retrained to provide control and feedback sensation for the individual. While the effect experienced by most of the individuals involved was subtle, one woman, paralyzed in a car accident thirteen years prior, is now standing and walking with the aid of a walker and braces. Nicolelis says that if they can develop this effect further, it may not turn out to be a mobility aid as intended, but rather a new therapy that might allow paraplegics to walk again, using their own limbs.