Abstract
Objectives: The purpose of this study is to compare the difference between brain activation by immersive virtual reality (VR) distraction analgesia versus screen-only distraction during burn wound care-induced maximal pain. Methods: Tc-99m ECD brain perfusion SPECT was used as a surrogate of brain activation. The study received IRB approval. Five burn victims were enrolled in the study after informed consent. Patients underwent two sessions of Tc-99m ECD injection at the peak pain during burn wound care and subsequent SPECT imaging on two consecutive days. All five patients had only standard analgesia in one session as a control and four patients had standard analgesia together with playing immersive and interactive VR game using VR goggles in the other session. Due to instrumental malfunction, the fifth patient played the same game on standard computer monitor, in addition to standard analgesia. Automated regional quantitative analysis of SPECT images in both control scans and VR/screen-only scans normalized to global brain activation was performed. Mean brain activation in the four VR patients was compared to activation in the screen-only patient. Results: The most prominent differences in regional brain activation with distraction were increased activation noted in the caudate nuclei and brain stem. In the right caudate nucleus, the mean activity level (normalized to global activity) in the four VR scans was 1.08 compared to 0.96 in their control scans (+0.12 change), while in the screen-only scan was 1.04 compared to 1.0 in its control scan (+0.04 change). In the left caudate nucleus, the mean activity level in the four VR scans was 1.05 compared to 0.97 in their control scans (+0.08 change), while in the screen-only scan was 1.10 compared to 1.12 in its control scan (-0.02 change). In the brain stem the mean activity level in the four VR scans was 0.88 compared to 0.83 in their control scans (+0.05 change), while in the screen-only scan was 0.86 compared to 0.87 in its control scan (-0.01 change). Brain stem activation in the VR scans was particularly localized in the periaqueductal gray matter region of the midbrain. Conclusion: Despite the small number of subjects; our findings suggest that previous reports of immersive VR analgesia superiority to screen-only distraction can be explained by VR-related activation of the caudate nuclei and midbrain that might be related to endogenous opioid release.