Robotic TruST to train people with spinal cord injuries

Engineers at Columbia University in New York have developed the Trunk-Support Trainer (TruST), a robotic device designed to assist and train people with spinal cord injuries.

Columbia Engineering’s TruST is expected to help people with spinal cord injuries (SCI) sit more stably by improving trunk control, which then expands a person’s active sitting workspace without them falling over or using their hands to balance. The study is described in Spinal Cord Series and Cases.

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“We designed TruST for people with SCIs who are typically wheelchair users,” said Sunil Agrawal, the project’s principal investigator and professor of mechanical engineering and of rehabilitation and regenerative medicine. “We found that TruST not only prevents patients from falling, but also maximises trunk movements beyond patients’ postural control, or balance limits.”

According to the university, TruST is a motorised-cable driven belt placed on the user’s torso to determine the postural control limits and sitting workspace area in people with SCI. It is said to deliver forces on the torso when the user performs upper body movements beyond the postural stability limits while sitting.

TruST
Illustration showing the architecture of TruST (Image: Sunil Agrawal and Victor Santamaria/Columbia Engineering)

Five subjects with SCI who participated in the pilot study were examined with the Postural Star-Sitting Test, a customised postural test that required them to follow a ball with their head and move their trunk as far as possible, without using their hands. The test was repeated in eight directions, and the researchers used the results to compute the sitting workspace of each individual.

The team modified the TruST for each subject to apply personalised assistive force fields on the torso while the subjects repeated the movements. With the TruST, the subjects were reportedly able to reach further during the trunk excursions in all eight directions and expand the sitting workspace around their bodies by an average of 25 per cent.

“The capacity of TruST to deliver continuous force-feedback personalised for the user’s postural limits opens new frontiers to implement motor learning-based paradigms to retrain functional sitting in people with SCI,” said Victor Santamaria, a physical therapist, postdoctoral researcher in Agrawal’s Robotics and Rehabilitation Laboratory, and first author of the paper. “We think TruST is a very promising SCI rehab tool.”

Every year, there are an estimated 17,000 new SCIs in the US alone. In addition, the rate of SCIs in people 65-years or older is expected to rise in the US, from 13 per cent in 2010 to 16.1 per cent by 2020. Data also shows a high survival rate for these patients, who need to function in everyday life but find sitting to be a major challenge.