The Virtual “Enfacement Illusion” on Pain Perception in Patients Suffering from Chronic Migraine: A Study Protocol for a Randomized Controlled Trial

Background: given the limited efficacy, tolerability, and accessibility of pharmacological treatments for chronic migraine (CM), new complementary strategies have gained increasing attention. Body ownership illusions have been proposed as a non-pharmacological strategy for pain relief. Here, we illustrate the protocol for evaluating the efficacy in decreasing pain perception of the enfacement illusion of a happy face observed through an immersive virtual reality (VR) system in CM. Method: the study is a double-blind randomized controlled trial with two arms, involving 100 female CM patients assigned to the experimental group or the control group. The experimental group will be exposed to the enfacement illusion, whereas the control group will be exposed to a pleasant immersive virtual environment. Both arms of the trial will consist in three VR sessions (20 min each). At the baseline and at the end of the intervention, the patients will fill in questionnaires based on behavioral measures related to their emotional and psychological state and their body satisfaction. Before and after each VR session, the level of pain, the body image perception, and the affective state will be assessed. Discussion: this study will provide knowledge regarding the relationship between internal body representation and pain perception, supporting the effectiveness of the enfacement illusion as a cognitive behavioral intervention in CM.