Does robotic guidance influence the use of proprioception?

Abstract

There is a growing interest to use robotic guidance in neurorehabilitation settings. One reason could be that it offers highly reliable proprioceptive feedback. Recently, we observed that healthy individuals exhibit more symmetric discrete reaching movements after being exposed to robotic guidance. However, it was not clear if these trajectory symmetry effects were associated with more proprioceptive feedback use or more movement planning. In this study, we sought to determine if trajectory symmetry during physical guidance could promote proprioceptive feedback use. Participants completed 210 training trials to 3 targets (27, 30, 33 cm), either manually aiming to the target, or led through a symmetric or an asymmetric velocity profile provided by a robot arm. All participants completed 10 baseline trials, the training phase, and 20 post-test trials. The post-test included 10 trials with tendon vibration of the biceps brachii tendon during the movement and 10 control trials. Vibration and control trials were blocked and counterbalanced across participants. As expected, a significant target undershoot was observed when vibration was applied. However, this bias did not differ across groups, indicating that robotic guidance did not promote the use of proprioceptive feedback in healthy individuals. Thus, robot-guided motor skill acquisition may not modulate the use of online proprioceptive feedback.

Acknowledgments: This research was supported by the Natural Sciences and Engineering Research Council (NSERC), the Canada Foundation for Innovation (CFI) and the Ontario Research Fund (ORF).