Background and Hypothesis A primary disruption of the bodily self is considered a core feature of schizophrenia (SCZ). The “disembodied” self might be underpinned by inefficient body-related multisensory integration processes, normally occurring in the peripersonal space (PPS), a plastic sector of space surrounding the body whose extent is altered in SCZ. Although PPS is a malleable interface marking the perceptual border between self and others, no study has addressed the potential alteration of its plasticity in SCZ. We investigated the plasticity of PPS in SCZ patients after a motor training with a tool in the far space. Study Design Twenty-seven SCZ patients and 32 healthy controls (HC) underwent an audio-tactile task to estimate PPS boundary before (Session 1) and after (Session 3) the tool-use. Parameters of PPS, including the size and the slope of the psychometric function describing audio-tactile RTs as a function of the audio-tactile distances, were estimated. Study Results Results confirm a narrow PPS extent in SCZ. Surprisingly, we found PPS expansion in both groups, thus showing for the first time a preserved PPS plasticity in SCZ. Patients experienced a weaker differentiation from others, as indicated by a shallower PPS slope at Session 1 that correlated positively with negative symptoms. However, at Session 3, patients marked their bodily boundary in a steeper way, suggesting a sharper demarcation of PPS boundaries after the action with the tool. Conclusions These findings highlight the importance of investigating the multisensory and motor roots of self-disorders, paving the way for future body-centred rehabilitation interventions that could improve patients’ altered body boundary.

IntroductionIn schizophrenia, there is evidence for anomalies in the extension and plasticity of the peripersonal space (PPS), the portion of space surrounding our body, plastically shaped through motor experiences. An impaired multisensory integration at the PPS level would underpin the disembodiment, a core feature of the disorder linked to subjective perturbations of the sense of self (“Self-disorders”) and of the intersubjective dimension (“schizophrenic autism”).ObjectivesThe present study was aimed at: 1) exploring possible associations between PPS data, psychopathological dimensions, and subjective experiences in schizophrenia; 2) identifying a specific PPS profile in patients with early-onset schizophrenia.MethodsA motor training with a tool was used to assess the PPS size and boundaries demarcation in twenty-seven schizophrenia outpatients. Moreover, they underwent a thorough psychopathological evaluation with the Positive And Negative Syndrome Scale (PANSS), the Examination of Anomalous Self Experience scale (EASE) and the Autism Rating Scale (ARS). Subsequently, the sample was divided into early (EOS) and adult-onset (AOS) subgroups, that were compared with respect to their PPS and psychopathological profiles.ResultsPPS features (size and boundaries demarcation) were associated with PANSS negative score, subjective experiences of existential reorientation (EASE Domain 5 scores) and traits of schizophrenic autism (ARS scores; Fig. 1). PPS parameters (Fig. 2) and ARS scores, but not PANSS and EASE differentiated between early and adult-onset subgroups.Image:Image 2:ConclusionsOur results suggest a link between PPS patterns, negative symptoms, and disturbances of the subjective experience, particularly in the intersubjective domain, in schizophrenia. Moreover, they candidate specific PPS profiles and schizophrenic autism traits as EOS markers.Disclosure of InterestNone Declared

IntroductionThe disruption of minimal Self is believed to be a core element of Schizophrenia and intimately connected to a disruption of bodily self, which in turn leads to impairments in intersubjectivity dimension. Motor abnormalities have been associated to Schizophrenia since the early conceptualization of the disorder, as well as inefficient body-related multisensory integration processes are considered nowadays a plausible origin of disembodied Self. In particular, there is evidence for significant abnormalities in Peripersonal Space (PPS) extension in Schizophrenia patients. PPS is the plastic sector of space immediately surrounding our body, whose coherent representation is based on efficient body-related multisensory integration processes. With a specific experimental task based on multisensory integration processing, we estimated PPS size and PPS boundary’s demarcation in 27 Schizophrenia patients, confirming a narrower PPS size and weaker bodily boundary in patients, thus paving the way for a deeper investigation of the mechanisms underlying the disruption of bodily self (Ferroni et al., Schziophr.Bull.2022, 5 1085-1093). We suggest that disembodiment might be responsible for the loss of the immediate linkage between Self and others (“intercorporeality”), so linking the disruption of the corporeal dimension to specific anomalies of intersubjectivity in Schizophrenia patients. Since language is one of the most important instrument through which intersubjectivity unfolds, it is intriguing to hypothesize a connection between language and multi-sensory processing.ObjectivesTherefore, the present study was aimed at investigating possible correlations between patients’ motor impairments in multi-sensory integration processes and their alterations in language and communicative interactions.MethodsTwenty-five outpatients were recruited in an experimental task investigating PPS extension; they were administered the Scale for the Assessment of Thought, Language and Communication (TLC) and the Clinical Language Disorder Rating Scale (CLANG).ResultsOur data showed significant correlations between TLC and CLANG total scores and PPS size, with narrower PPS size for more severe formal thought disorders and higher language and communication impairments.ConclusionsOur preliminary results seem to confirm the presence of a link between language impairment and multi-sensory processing, suggesting that bodily and linguistic disorganization may have a common origin which has yet to be explored in depth. Future research is needed to identify linguistic and motor endophenotypic patterns, potentially intertwined with each other, capable of early predicting Schizophrenia development and thus usable as early diagnostic tools.Disclosure of InterestNone Declared

Introduction A primary disruption of the bodily self is considered a core feature of schizophrenia patients (SCZ). The “disembodied” self would be underpinned by an inefficient body-related multisensory integration mechanism occurring in the Peripersonal Space (PPS). PPS is a plastic sector of space surrounding our body, whose extent is altered in SCZ. Although PPS represents a malleable interface marking the perceptual border between self and others, no study has investigated the potential alteration of its plasticity in SCZ. Objectives We investigated the PPS extension and its plasticity in SCZ and their potential correlations with the clinical scales. Methods Thirty SCZ and thirty healthy controls (HC) underwent a multisensory task to estimate PPS boundary before and after a motor training. Patients were also administered the Positive And Negative Syndrome Scale (PANSS) and the Examination of Anomalous Self-Experience (EASE). Results Data confirm a narrower PPS extent in SCZ than in HC, whereas no differences in PPS expansion was found in the two groups after the motor training (Figure 1). Positive symptoms were associated directly with PPS extent and inversely with PPS plasticity. No associations were found between PPS and EASE domains. Figure1: Graphical representation of PPS expansion in SCZ and HC. Both panels show individual normalized sigmoid fits Conclusions The present study suggests a narrower PPS extent and a preserved PPS plasticity in SCZ with respect to HC. Both PPS extent and plasticity are related to the severity of positive symptoms. These results highlight the potential role of rehabilitation interventions in order to improve patients’ weakened body boundary. Disclosure No significant relationships.