Circumplex Model of Affect: A Measure of Pleasure and Arousal During Virtual Reality Distraction Analgesia.

OBJECTIVE Immersive virtual reality (VR) distraction provides clinically effective pain relief and increases subjective reports of "fun" in medical settings of procedural pain. The goal of this study was to better describe the variable of "fun" associated with VR distraction analgesia using the circumplex model (pleasure/arousal) of affect. MATERIALS AND METHODS Seventy-four healthy volunteers (mean age, 29 years; 37 females) received a standardized, 18-minute, multimodal pain sequence (alternating thermal heat and electrical stimulation to distal extremities) while receiving immersive, interactive VR distraction. Subjects rated both their subjective pain intensity and fun using 0-10 Graphic Rating Scales, as well as the pleasantness of their emotional valence and their state of arousal on 9-point scales. RESULTS Compared with pain stimulation in the control (baseline, no VR) condition, immersive VR distraction significantly reduced subjective pain intensity (P < 0.001). During VR distraction, compared with those reporting negative affect, subjects reporting positive affect did so more frequently (41 percent versus 9 percent), as well as reporting both greater pain reduction (22 percent versus 1 percent) and fun scores (7.0 ± 1.9 versus 2.4 ± 1.4). Several factors-lower anxiety, greater fun, greater presence in the VR environment, and positive emotional valence-were associated with subjective analgesia during VR distraction. CONCLUSIONS Immersive VR distraction reduces subjective pain intensity induced by multimodal experimental nociception. Subjects who report less anxiety, more fun, more VR presence, and more positive emotional valence during VR distraction are more likely to report subjective pain reduction. These findings indicate VR distraction analgesia may be mediated through anxiolytic, attentional, and/or affective mechanisms.