The (overgrown) body in social context: how atypical body features shape cognitive and socio-emotional development in overgrowth syndromes

Embodied cognition accounts have provided striking evidence of how cognitive, affective and social processes are deeply rooted in the embodied experience. The way an individual perceives his/her own body has crucial, but often neglected, implications for social interaction and for psychological development. This thesis is composed by two research projects that investigate body perception and its impact on psychosocial functioning in healthy adults and in children and adolescents with overgrowth syndromes, respectively. A first project is aimed at investigating affective touch, a specific dimension of body perception that plays a primary role in conveying emotions and in forming social bond. Vicarious perception of affective touch is assessed in healthy adults through behavioural and neurophysiological experiments. The main research project addresses how cognitive and socio-emotional development is influenced by being born with an overgrowth syndrome, specifically Beckwith-Wiedemann (BWS), Malan and Sotos syndromes. Body perception, cognitive and emotional-behavioural development are investigated by means of a series of experiments and standardized assessments, involving children and adolescents with overgrowth syndromes as well as individuals with other genetic disorders and healthy participants. The first chapter offers a narrative review of previous research on the multidimensional construct of body perception. The emergence of embodied cognition theories provides a theoretical and empirical framework for understanding the complex interactions between body, emotion and cognition in healthy and clinical populations. The second chapter presents the results of the project investigating vicarious perception of affective touch in healthy adults. Two consecutive studies provide behavioural and neurophysiological evidence of how we understand the affective and social meaning of touch during observation of interpersonal interactions. The third chapter offers an overview of the project on overgrowth syndromes and then describes the neuropsychological profiles and educational outcomes in children and adolescents with BWS, Sotos and Malan syndromes. Two studies document the neuropsychological profiles of other genetic disorders, namely Williams syndrome and Joubert syndrome. The results and the indirect comparison with these disorders provide indications on cognitive development and the interplay between body, cognition and social context in overgrowth syndromes. The fourth chapter reports the results of a multidimensional assessment of body perception in adolescents with overgrowth syndromes compared to healthy peers. Specifically, body image disturbances, body-related representations of action and social spaces, interoceptive sensitivity to cardiac signals, and bodily illusions of ownership over a virtual body are assessed. The fifth chapter examines the presence of emotional-behavioural problems and autistic traits in children with BWS, Sotos and Malan syndromes. A study investigating psychosocial difficulties in preschool-age children with BWS is presented as well. The findings highlight the socio-behavioural phenotypes of BWS, Sotos and Malan syndromes, which are discussed considering socio-cognitive abilities and clinical features of each condition. Lastly, the results of the two projects and their implications for future research and for clinical management of overgrowth syndromes are discussed.