Effects of inpatient treatment of adolescents with anorexia nervosa are associated with body representation: a monocentric pilot study.

This monocentric pilot study investigates the relationship between nutritional treatment and body representation distortion in adolescents with Anorexia Nervosa (AN) using the Rubber Hand Illusion (RHI) task. A total of 28 adolescents participated, including 14 patients with restrictive AN and 14 healthy controls. The RHI and Robot Hand Illusion (RoHI) tasks were conducted, with assessments taken at admission and discharge for the AN group. Sense of Ownership (SO) and Sense of Agency (SA) rated via 7-item Likert; proprioceptive drift was millimetre shift in perceived hand position after stimulation vs baseline under congruent (sync/in-phase) or incongruent (async/out-of-phase) feedback. Results showed that all groups exhibited higher SO scores in the synchronous condition compared to the asynchronous condition in the RHI task. In the RoHI task, AN patients at admission displayed significantly higher SA scores in the in-phase than in the out-of-phase condition. Notably, SO scores in the RHI task at discharge were positively correlated with weight recovery one month post-discharge (ρ = 0.59). These findings suggest that inpatient treatment influences body representation in adolescents with AN and that changes in body perception may serve as an indicator of treatment effectiveness.