Robotic Exoskeleton and Virtual Reality Help Paraplegics to Walk
Andrew Wheeler posted on August 18, 2016 |

However you feel about the validity of academic journal articles, you generally need to read through them to determine if what the article discusses is highly conditional and specialized, or whether the findings can be applied to different industries.

Miguel Nicolelis of Duke University is best known for his work with a research team that used arrays of electrode implants to detect motor intent by decoding the signals of hundreds of motor neurons while a monkey used a joystick to move a shape in a video game. These signals were also sent to a robotic arm that, in turn, then made the same movements as the monkey. After the monkey realized the correlation, it let go of the joystick and controlled the game with thought.

Besides “reading monkey thoughts,” Nicolelis has been experimenting with helping paraplegics to walk again using a combination of technologies, including a custom-built virtual reality (VR) training module, along with walking devices that are currently being used in physical therapy. The applications of this work in the medical industry have the potential to be extensive.

Nicolelis has been experimenting with robotics and prosthetic limbs in his lab for about two decades now. The paper he and his team published in Scientific Reports is intriguing because it shows that through a combination of a brain-machine interface and VR, patients were able to simulate control over their paralyzed legs and regain some sensation and control over their own muscle function below their spinal cord injuries.

The combination of the brain-machine interface and VR training have the potential to rekindle a connection to spinal nerves that may remain intact in even the most severe cases of paraplegia. The nerves go quiet after not receiving signals from the cortex, but this research team banked on engaging the nervous system’s plasticity, which allows it to inherently adapt to changes in stimuli and environment.

Given the hundreds of thousands of people who experience minor to major paralysis as a result of spinal cord injuries worldwide, the research has the potential to be impactful, not just because of its significance to paraplegics, but because it appears to be a scalable technology that could go viral with spine injury professionals.

How It Was Designed

In the study, eight patients wore a noninvasive electroencephalogram (EEG) cap attached to 11 brain-recording electrodes. The patients also wore an Oculus Rift, which had a simulated virtual body. Their only goal was to create movements in their avatar’s digital legs.

At first, nothing happened and the EEG recorded zero activity in parts of the brain associated with walking. But after two hours of practice a week for over a year, each of the eight participants showed improvement. They regained some sensation and muscle control beneath their spinal cord injuries. 

A patient in the study using an Oculus Rift to simulate walking while the EEG records brain activity. (Image courtesy of Walk Again Project).
A patient in the study using an Oculus Rift to simulate walking while the EEG records brain activity. (Image courtesy of AASDAP/Duke University).

 

Training by Suiting up into a Robotic Exoskeleton

After VR training, the research team engaged the patients in exercises designed to focus on balance and posture. For example, the patients spent time testing walking devices with overhead harnesses designed to support the full weight of their bodies. Some patients tried out an experimental robotic exoskeleton reminiscent of Ripley’s Power Loader in Aliens.

The point was to create enough simulation to trick the brain into thinking it was able to walk around under its own volition. The illusion of control and experience was bolstered by a haptic sleeve, which would send different pressure signals to a patient’s arm when they walked on different types of ground surfaces. This haptic feedback synchronizes with the brain, and creates the illusion for the patients that they are walking by themselves.

The entire goal is to induce plasticity to the spinal cord as well as the brain.


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