A pilot study on the effects of a physio-avatar EB experience on motor performance.

Introduction: Neurorehabilitation using virtual reality (VR) and electromyography has garnered attention in recent years. The authors developed a system based on these technologies that enables participants to experience an avatar (physio-avatar EMG biofeedback, PAEB) with arbitrary dynamics in VR environments, controlled by their own EMG signals. Using this system, the study examined whether experiencing an avatar that feels slower than the real body can promote the relearning of cerebellar Methods: Experiments were conducted in 30 healthy adults. Participants were assigned to four groups: the PAEB adaptation group (n = 6), which underwent prolonged PAEB training; the PAEB nonadaptation group (n = 7), which received only short-term PAEB exposure; the control group (n = 8), which experienced a real-body avatar (RBA) reflecting actual movements without EMG control; and the resistance training (RT) control group (n = 9), which performed isometric contractions comparable to the PAEB adaptation group without visual avatar feedback. Motor performance was evaluated based on angular velocity during a real-body reaching task. Each group performed the task before and after the adaptation phase to assess the effects of PAEB exposure. Subjective questionnaires were administered to evaluate the sense of ownership (SoO) and sense of agency (SoA). Results: Subject-level one-tailed Mann-Whitney U Discussion: The improvement in motor performance observed in the PAEB adaptation group suggests that exposure to an avatar with altered bodily dynamics modifies motor control strategies through error-driven updating of internal models. This interpretation is supported by the RT control group, which showed no improvement despite experiencing comparable physical load. These findings indicate that the enhancement in motor speed is more likely attributable to internal model recalibration via error learning than to acute neuromuscular responses to physical training. Conclusion: These results indicate that experiencing the PAEB-an avatar that appears to move slower than one's own body-can potentially improve motor performance. However, as the number of participants who underwent PAEB training was limited, further studies with a larger sample size are required to confirm these findings.