| Popis: |
BACKGROUND: Anomalous bodily experiences are central to schizophrenia symptomatology and play a major role in social and functional outcome. Interoception, the awareness of our internal bodily signals, allows us to maintain homeostasis or initiate help-seeking behavior. Internal bodily sensations are also crucial to emotional experiences. Specifically, emotional embodiment allows us to identify and communicate our affective states and understand the emotional experiences of others. Importantly, the fidelity and precision of perceived internal signals may be critical to these adaptive functions. In a previous study (Chon et al, in prep), we found more precise representation of embodied emotions in proprioceptive and interoceptive experts (e.g., athletes). Although much has been written about the phenomenology of bodily disturbances in schizophrenia, few studies have used empirical tasks to investigate these minimal self-impairments. The goal of this study was to estimate the quality of two internal signals, heartbeat and emotional embodiment, to elucidate the mechanisms underlying self-disturbances in schizophrenia. Given the prevalence of bodily disturbances in schizophrenia, we hypothesized that internal signals would be noisier in patients compared to controls. METHODS: We recruited 23 individuals with schizophrenia (SZ) and 21 demographically matched controls (CO). Interoceptive ability was measured using the Heart Beat Counting Task (Shandry, 1981). Interoceptive accuracy (i.e., the objective performance) and interoceptive awareness (i.e., the metacognitive awareness of interoceptive ability) were computed for each participant. A topographical body mapping tool (Nummenmaa et al., 2014) was used to generate spatial maps of bodily sensations that correspond to distinct emotion categories. Self-disturbances were assessed using the IPASE. In CO, schizotypy was assessed with the SPQ-B. Symptoms were rated with SANS and SAPS. RESULTS: Interoceptive accuracy was reduced in SZ compared to CO, but there were no group differences in interoceptive awareness. The topographical maps of emotions showed less precisely defined regions of bodily sensations in the context of emotions compared to CO. In particular, classification accuracy analyses revealed higher independence of bodily maps across emotions in CO compared to SZ. Furthermore, SZ reported higher levels of “mixed” bodily sensation of emotions (i.e., both activation and deactivation in the same bodily region). No differences were found in the magnitude of bodily sensation reported by SZ and CO, which suggests that the strength of felt bodily sensation of emotions is equivalent. CONCLUSIONS: Bodily sensations corresponding to emotion categories in SZ were reduced in spatial precision, which corroborates the hypothesis of increased levels of internal noise in schizophrenia. This difficulty with perceiving internal states might contribute to minimal self-disturbances and affect functional outcome. Future work will bridge the gap between empirical evidence and phenomenological symptoms by directly examining the role of internal noise on experienced self-disturbances. |
