Supplementary Material for: Self-Disorder and Brain Processing of Proprioception in Schizophrenia Spectrum Patients: A Re-Analysis

Background: Anomalies of self-awareness (self-disorders, SDs) are theorized to be basic to schizophrenia psychopathology. We have previously observed dysfunction of brain processing of proprioception in schizophrenia spectrum disorders (SZS). We hypothesized that SDs could be associated with abnormalities of early contralateral proprioceptive evoked oscillatory brain activity. Methods: We investigated the association between proprioceptive evoked potential components and SDs in a re-analysis of data from a subsample (n = 12) of SZS patients who had previously been observed with deviant proprioceptive evoked potentials and interviewed with the Examination of Anomalous Self-Experience (EASE) scale. Results: Higher EASE scores (i.e. increased SD) were associated with lower peak parietal gamma frequencies and higher peak beta amplitudes over frontal and parietal electrodes in the left hemisphere following right-hand proprioceptive stimulation. Conclusion: Disorders of self-awareness may be associated with dysfunction of early phases of somatosensory processing. The findings are potentially relevant to our understanding of the pathophysiology of schizophrenia, but further studies are needed.