Where is My Hand? Assessing Visuo-Tactile Integration of Hand and Shoulder After Virtual Reality Training Using a Body-Machine Interface

Immersive virtual reality (VR) has potential for enhancing rehabilitation in clinical populations, such as individuals with stroke, but many face usability challenges. A promising approach involves a Body-Machine Interface using shoulder movements to control a virtual hand, potentially altering body perception. Investigating bodily illusions is crucial for expanding therapeutic applications. This study examines how a single VR motor-training session, using shoulder movements to control a virtual hand, affects brain representations of the real hand and shoulder. The Crossmodal Congruency Test (CCT) was adapted to assess the visuo-tactile interaction between the shoulder and hand in neurotypical participants before and after VR training. Nine participants controlled the virtual hand with shoulder movements, while eight used their fingers, both receiving shoulder tactile feedback. No significant differences were found in hand-to-shoulder visuo-tactile integration. The results suggest that the Body-Machine Interface may not alter bodily representations of the hand and shoulder, or that tactile feedback alone could elicit changes. Although the results did not fully meet expectations, the study provided valuable insights and identified methodological limitations for future research.