According to the researchers from Columbia University in the US, the robotic device – the Trunk-Support Trainer, or TruST – is a motorised-cable driven belt placed on the torso of people with SCI to determine their control limits of posture, and workspace area while sitting.
They said the device delivers forces on the torso when the user performs upper body movements beyond the postural stability limits while sitting.
The study, published on Monday in the journal Spinal Cord Series and Cases, is the first to measure and define the sitting workspace of patients with SCI based on their active trunk control.
“We designed TruST for people with SCIs who are typically wheelchair users,” said study co-author Sunil Agrawal from Columbia University.
“We found that TruST not only prevents patients from falling, but also maximizes trunk movements beyond patients’ postural control, or balance limits,” he added.
Five subjects participated in a pilot study examining TruST with the Postural Star-Sitting Test.
In this customised postural test, the participants were required to follow a ball with their head and move their trunk as far as possible, without using their hands.
The users repeated the test in eight directions, following which the researchers used the results to compute the sitting workspace of each individual.
TruST was customized for each subject, the researchers said, so that they could apply personalized assistive force fields on the torso while the participants performed the same movements again.
With the new robotic device, the subjects could reach further during the trunk excursions in all eight directions.
According to the study, TruST significantly expanded the sitting workspace around their bodies, on an average of about 25 per cent more.
“The capacity of TruST to deliver continuous force-feedback personalized for the user’s postural limits opens new frontiers to implement motor learning-based paradigms to retrain functional sitting in people with SCI. We think TruST is a very promising SCI rehab tool,” said study co-author Victor Santamaria, a physical therapist at Columbia University.
Agrawal and his team are now exploring the use of TruST to improve the trunk control of adults and children with SCI.
“The robotic platform will be used to train participants with SCI by challenging them to move their trunk over a larger workspace, with TruST providing assist-as-needed force fields to safely bring the subjects back to their neutral sitting posture. This force field will be adjusted to the needs of the participants over time as they improve their workspace and posture control,” Agrawal said.