How Body Movement Influences Virtual Reality Analgesia?

In this study, we tested the hypothesis that increased body movement while steering a virtual reality game leads to the diminished experience of pain. We also investigated the relationship between presence in a virtual environment and pain intensity. 30 students of Wroclaw University participated in the within subject experiment. The participants were looking at the game through head mounted displays. In two experimental conditions a participant navigated the game using a computer mouse (a small movement), or a Microsoft Kinect (a large movement). Thermal (cold) stimulation was used to inflict pain. While playing the game, the participants immersed their non-dominant hands in a container with cold water (temperature 0.5 - 1.5°C). Two measures were used to assess the pain experience -- the amount of time the participants spent keeping their hands in cold water (pain tolerance), and Visual Analogue Scale (pain intensity). The participants also completed the I group Presence Questionnaire (IPQ), measuring the sense of presence experienced in a virtual environment. The predictions were partly confirmed by the results -- the participants were keeping their hands in cold water significantly longer in the large movement condition compared to the small movement condition. However, there was no significant difference on pain intensity results between the two experimental conditions. Similarly, we failed to find any correlations between IPQ dimensions and the pain measures used in the study. Several possible mechanisms underlying the observed relationship between movement and pain experience are discussed.