Implicit body representation in Anorexia Nervosa: Insights from a Virtual Reality Task

Anorexia Nervosa (AN) is a complex psychiatric disorder characterized not only by weight loss and fear of weight gain, but also by a disturbed experience of body weight and shape. Body representation is multidimensional, involving both explicit body image and more implicit sensorimotor components, which may be altered in different ways in AN. As presented in Chapter 2, the aim of the project was to investigate implicit body representation in healthy participants and in patients with AN, and to explore whether this implicit measure was related to explicit body image measures. Chapters 3 and 4 describe the two studies using a VR-based approaching-dot task. Study 1 involved healthy participants, while Study 2 included patients with AN and a healthy control group. In both studies, participants completed the implicit task together with self-report measures of body image and eating-disorder-related symptoms. In Chapter 3, Study 1 showed that healthy participants tended to underestimate their body size in the implicit task, especially at the hip region. In Chapter 4, Study 2 showed that patients with AN did not display the same underestimation pattern, and their performance was closer to zero. In both studies, the implicit measure was only weakly related, or not related, to the explicit questionnaires. Overall, the thesis suggests that implicit body representation is not fully captured by explicit body image measures and may represent a partially independent level of bodily processing. The lack of significant associations between implicit and explicit measures further supports a multidimensional view of body representation in AN, in which perceptual, evaluative and sensorimotor components may dissociate. Overall, the study provides preliminary evidence that VR-based implicit tasks may be useful for investigating body perception in AN and for informing future assessment and intervention strategies.