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.

Parnas J, et al: EASE: Examination of Anomalous Self-Experience. Psychopathology 2005;38:236-258.
Raballo A, Saebye D, Parnas J: Looking at the schizophrenia spectrum through the prism of self-disorders: an empirical study. Schizophr Bull 2011;37:344-351.
Arnfred SM, Hemmingsen RP, Parnas J: Delayed early proprioceptive information processing in schizophrenia. Br J Psychiatry 2006;189:558-559.
Arnfred S, et al: Attenuation of beta and gamma oscillations in schizophrenia spectrum patients following hand posture perturbation. Psychiatry Res 2011;185:215-224.
Parnas J, Handest P: Phenomenology of anomalous self-experience in early schizophrenia. Compr Psychiatry 2003;44:121-134.
McGuffin P, Farmer A, Harvey I: A polydiagnostic application of operational criteria in studies of psychotic illness. Development and reliability of the OPCRIT system. Arch Gen Psychiatry 1991;48:764-770.
Raballo A, Parnas J: Examination of anomalous self-experience; initial study of the structure of self-disorders in schizophrenia spectrum. J Nerv Ment Dis 2012;200:577-583.
Delorme A, Makeig S: EEGLAB: an open source toolbox for analysis of single-trial EEG dynamics including independent component analysis. J Neurosci Methods 2004;134:9-21.
Morup M, Hansen LK, Arnfred SM: ERPWAVELAB: a toolbox for multi-channel analysis of time-frequency transformed event related potentials. J Neurosci Methods 2007;161:361-368.
Arnfred SM, et al: Attenuation of beta and gamma oscillations in schizophrenia spectrum patients following hand posture perturbation. Psychiatry Res 2011;185:215-224.
Williams S, Boksa P: Gamma oscillations and schizophrenia. J Psychiatry Neurosci 2010;35:75-77.
Gandal MJ, et al: Gamma synchrony: towards a translational biomarker for the treatment-resistant symptoms of schizophrenia. Neuropharmacology 2012;62:1504-1518.
Roach BJ, Mathalon DH: Event-related EEG time-frequency analysis: an overview of measures and an analysis of early gamma-band phase locking in schizophrenia. Schizophr Bull 2008;34:907-926.
Spencer KM, et al: Neural synchrony indexes disordered perception and cognition in schizophrenia. Proc Natl Acad Sci USA 2004;101:17288-17293.
Andreasen NC, et al: Correlational studies of the Scale for the Assessment of Negative Symptoms and the Scale for the Assessment of Positive Symptoms - an overview and update. Psychopathology 1995;28:7-17.
Lee KH, et al: Synchronous gamma activity: a review and contribution to an integrative neuroscience model of schizophrenia. Brain Res Brain Res Rev 2003;41:57-78.
Light GA, et al: Gamma band oscillations reveal neural network cortical coherence dysfunction in schizophrenia patients. Biol Psychiatry 2006;60:1231-1240.
Haig AR, et al: Gamma activity in schizophrenia: evidence of impaired network binding? Clin Neurophysiol 2000;111:1461-1468.
Palva S, et al: Early neural correlates of conscious somatosensory perception. J Neurosci 2005;25:5248-5258.
Dockstader C, et al: Abnormal neural reactivity to unpredictable sensory events in attention-deficit/hyperactivity disorder. Biol Psychiatry 2009;66:376-383.
Szurhaj W, et al: Intracerebral study of gamma rhythm reactivity in the sensorimotor cortex. Eur J Neurosci 2005;21:1223-1235.
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.