Functional brain connectivity correlates of pain relief during virtual reality exposure in cancer patients

Virtual reality (VR) has shown promise for pain relief, including in cancer-related contexts, yet its underlying neurophysiological correlates remain unclear. Understanding brain-based correlates is important for evaluating VR programs and informing personalized pain management. Functional connectivity reflects coordinated activity among pain-related brain regions.

This study examined associations between changes in functional connectivity and pain reduction during VR exposure using functional near-infrared spectroscopy (fNIRS) in cancer patients with chronic neuropathic and/or somatic pain. In an IRB-approved study, 41 cancer patients underwent a VR distraction session using the Oceania application on a Meta Quest® headset. Continuous fNIRS signals focused on oxygenated hemoglobin (HbO) were recorded. Pain intensity was assessed before and after VR using the FACES Pain Scale-Revised. Functional connectivity was estimated using coherence analysis, and associations with pain reduction were evaluated using Pearson correlation with false discovery rate correction.

Extracted functional connectivity features showed significant negative correlations with pain reduction, particularly between channels spanning prefrontal cortex (PFC), bilateral parietal lobes [including the primary somatosensory cortex (S1)], and superior frontal gyrus (SFG). Strongest associations were observed between PFC and SFG (r = -0.43, p = 0.005), and within SFG (r = -0.42, p = 0.006). HbO activity at the PFC was significantly associated with pain reduction (r = -0.32, p = 0.044).

Decreased functional connectivity in specific cortical regions was observed in association with short-term pain reduction during VR exposure. Findings suggest that functional connectivity features may represent candidate neurophysiological correlates of pain changes in immersive VR contexts.