Peripersonal space and interpersonal distance as windows onto multisensory body representation in adolescents with overgrowth syndromes.

INTRODUCTION: Peripersonal space (PPS) and interpersonal distance (IPD) reflect related but dissociable representations of the space around the body, both relevant to multisensory and social development. However, whether physical overgrowth is associated with an altered regulation of body-related space remains unknown, despite growing evidence of psychosocial difficulties in individuals with overgrowth syndromes. METHODS: This study aimed to characterize PPS and IPD in adolescents with overgrowth syndromes, specifically Beckwith-Wiedemann spectrum, Sotos syndrome, and Malan syndrome, and to test whether their expansion is associated with syndrome type, cognitive functioning, body size, and social-perceptual ability. Thirty-three adolescents with overgrowth syndromes and 33 age-matched controls completed separate comfort-distance and reachability judgments for social and non-social stimuli using a computerized stop-distance paradigm. RESULTS: Adolescents with overgrowth syndromes showed overall larger PPS and IPD than controls, independent of autistic traits (p < 0.001, η 2 p  = 0.25). Within the clinical group, the relative expansion of IPD over PPS was larger in adolescents with Beckwith-Wiedemann spectrum (t 31 = -2.57, p = 0.015) and in those with average intellectual functioning (t 31 = -2.67, p = 0.012), pointing to a buffer space linked to feelings of safety. A larger buffer space was further predicted by better affect-recognition skills (β = 0.48, p = 0.010), independent of age and autism-like social challenges. The body mass index was selectively associated with PPS (r = 0.47, p = 0.006). DISCUSSION: These findings indicate that body-related spatial representations are enlarged in overgrowth syndromes, and that this expansion is shaped by cognitive functioning, body size, and social-perceptual ability rather than by autistic traits, contributing novel evidence to the study of typical and atypical multisensory development and its association with social functioning. This may also inform interventions targeting social participation in adolescents with overgrowth syndromes.