Body illusions for mental health: a systematic review

Body illusions (BIs) refer to altered perceptual states where the perception of the self-body significantly deviates from the configuration of the physical body, for example, in aspects like perceived size, shape, posture, location, and sense of ownership. Different established experimental paradigms allow to temporarily induce such altered perceptual states in a predictable and systematic manner. There is evidence demonstrating the use of BIs in clinical neuroscience, however, to our knowledge, this is the first systematic review evaluating the effectiveness of BIs in healthy and clinical populations. This systematic review examined the use of BIs in the healthy and clinical populations, and review how BIs can be adopted to enhance mental health in different mental illness conditions. The systematic review was conducted following the PRISMA guidelines. Of the 8086 studies identified, 189 studies were included for full-text analyses. Seventy-seven studies used BIs in clinical populations. Most of the studies using BIs with clinical populations used body illusions toward a body part, modulating the external aspects of body representation. Even though clinical studies showed the positive effects of BIs to improve mental illness conditions, future technologies using BIs targeting both the external (exteroceptive) and the internal (interoceptive) aspects of body representations can further improve the efficacy of this approach.