2022/04/13 | Research | Robotics

Effect of VR visualization on robotic motor rehabilitation

Immersive virtual reality (VR) may be able to augment the effects of neurorehabilitation with assistive robotic devices. The Motor Learning and Neurorehabilitation lab has asked healthy participants to perform a path-tracking task in VR while the rehabilitation robot was represented or omitted in the virtual environment to study the effects of these visualizations on users’ motivation, embodiment, and performance.

Virtual environment. A) & D) Third-person perspective showing the avatar and a whole path – This view was not presented to the participants. B) & C) Participants’ first-person perspective during the task, B) the invisible condition showing the path and the avatar, C) the visible condition also showing the robot and forearm cuff. (https://doi.org/10.1109/TNSRE.2022.3147260)

Today, most virtual environments for rehabilitation do not render the training robot that assists users during motor exercises, thus leading to a clash between users’ visual vs. haptic perception. A research team at the ARTORG Center has therefore compared how well 28 healthy users performed a path-tracking task in VR while an arm-robot was visual or hidden. In addition, the robot either assisted movements or did not.

The team found that the robot’s visibility did not affect participants’ motivation, embodiment, or task performance. Robotic assistance, on the other hand, did improve user motivation, but made it more difficult for participants to feel fully present in the virtual environment. Thus, for the clinical implementation, robotic assistance appears to be more relevant than faithfully reproducing the environment in VR.

Based on these findings, the Motor Learning and Neurorehabilitation lab is currently investigating what influence the complexity of the virtual environment (e.g., how many details are reproduced) has on motivation, embodiment, and performance. This information could help design robot-assisted motor rehabilitation in VR that adapts to individual patient training needs – e.g. providing more complex and challenging content for patients with less severe brain damage to keep them motivated.