A Novel Mutual Information-Based Approach for Neurophysiological Characterization of Sense of Presence in Virtual Reality

Objective: The presented work aimed to investigate neurophysiological markers of sense of presence in virtual reality (VR). The study was based on developing and preliminary validating a neurophysiological-based approach for sense of presence evaluation. Methods: A VR environment was designed to systematically modulate multisensory conditions, including visual, auditory, and vibrotactile stimuli. EEG, ECG, and EDA signals were recorded. The Mutual Information-based sense of presence index (SoPMI) was developed as a synthetic metric for sense of presence, integrating multiple physiological signals. Signal preprocessing and analysis were conducted using EEG-based Global Field Power (GFP) and Skin Conductance Level (SCL), among other parameters, to explore their relationship with sense of presence under different VR conditions. Results: The SoPMI index demonstrated sensitivity to varying levels of multisensory integration and immersion (all p < 0.001). EEG-derived features, particularly in theta and alpha bands, were highly correlated with subjective sense of presence scores (R = 0.559, p < 0.007). Additionally, autonomic markers, such as skin conductance, showed strong associations with engagement, particularly under high-immersion conditions. Conclusion: The study successfully identified neurophysiological markers of sense of presence and preliminarily validated the SoPMI index as a potential objective measure for VR applications. These findings establish a foundation for reliable and immersive VR experiences across fields, including training, rehabilitation and industry 5.0. Significance: By providing an objective and multimodal framework for measuring sense of presence, this research contributes to advancing VR applications where the sense of presence accurate and reliable assessment is essential. The SoPMI index offers potential for enhancing VR design and creating more effective, user-centered immersive experiences.