Your body, my experience: A systematic review of embodiment illusions as a function of and method to improve body image disturbance.

Abstract

Body image disturbance (BID) is a core feature of eating disorders and body dysmorphic disorder, with embodiment illusions offering the potential for understanding and treating BID through manipulating multisensory integration processes underlying self-perception. This systematic review is the first to evaluate evidence on whether (a) varying BID levels (i.e., BID-related diagnoses or higher levels of BID symptomatology) impact susceptibility to embodiment illusions and (b) embodiment illusions can improve BID symptomatology. Thirty-two studies involving clinical and community samples met the inclusion criteria. Generally, individuals with higher BID showed greater susceptibility to embodiment illusions compared to those with lower/no BID (nine of 14 studies, 64.29%). Most studies (20 of 24, 83.33%) found embodiment illusions produced improvements in BID, with medium to large effects across both findings. However, methodological heterogeneity and nonvalidated measures limit conclusions. Overall, results suggest multisensory integration disturbances underpin BID, while embodiment paradigms show promise as therapeutic interventions. Specific population factors (e.g., clinical diagnosis) and illusion parameters (e.g., body part stimulated, stimulation synchrony) influenced effects and warrant further investigation to optimize embodiment illusion paradigms. Despite limitations, this review highlights embodiment illusions as a valuable approach for elucidating mechanisms of BID and developing novel adjunctive treatments for BID-related conditions targeting multisensory integration deficits. Public Health Significance StatementBody image disturbance (BID) is central to eating disorders and body dysmorphic disorder. Embodiment illusions, inducing ownership over another body/body part, offer insight into BID and potential interventions. This first systematic review summarizes findings using embodiment illusions to understand and improve BID, highlights gaps and limitations, and proposes how these illusions may optimally be employed in BID research and clinical practice.

Whose body is it anyway? Cultural reflections on embodiment illusion research in eating disorders and body dysmorphic disorder

“…Of the 32 studies reviewed by Portingale et al. ( 48 ), only one included a non-WEIRD Asian sample, demonstrating that avatar embodiment improved body perceptions in Taiwanese individuals ( 50 ): however, this study did not assess illusion susceptibility or compare cultures. The remaining 31 reviewed studies from WEIRD samples also failed to address ethnicity or cultural factors.…”

“…Researchers have increasingly utilised embodiment illusions to understand and improve perceptual body image disturbance in EDs and BDD (i.e., body shape/weight misestimation), which has been neglected compared to cognitive, affective, and behavioural components in current research and intervention ( 48 ). A recent systematic review by Portingale et al ( 48 ) found that individuals with higher body image disturbance were more susceptible to these illusions, indicating potential multisensory integration deficits underlying perceptual image disturbances. Embodiment illusions were also shown to update and improve disturbed body perceptions: e.g., experiencing a full-body illusion with a healthy weight model reduced body size overestimation in anorexia nervosa samples.…”

“…Eye tracking and fMRI could elucidate cross-cultural differences in neural processes underlying illusion susceptibility and post-illusion improvements in image disturbances. Nuanced measures of face image disturbance are also needed, such as those capturing different components (e.g., dissatisfaction, concern, adiposity, avoidance, checking, contemplating surgery) and different facial features (e.g., eyes, nose) ( 48 , 53 ).…”