title: EEG coherence measures during auditory hallucinations in schizophrenia.
abstract: We studied the change in EEG alpha-band average coherence between auditory hallucination (AH) and non-auditory hallucination (non-AH) states in seven auditory hallucinating schizophrenia patients. Four cortical regions were considered based on the existing dominant models for auditory hallucinations, the inner speech model and the central auditory processing deficit (CAPD) model. Coherences between electrodes located over Broca's area (BA 44/45) and Wernicke's area (BA 22/42) and between electrodes located over left-right temporal cortices were examined. There was no significant change observed in the coherence between Broca's and Wernicke's areas, but a significant increase was observed in coherence between the left and right superior temporal cortices during AHs compared with non-AHs, suggesting increased bilateral coherence between auditory cortical areas. Since coherence is a pairwise measure of functional correlation between regions, our findings suggest abnormally increased synchrony between the left and right auditory cortices during AHs in schizophrenia. Further, a significant increase in relative power was observed in the left, but not in the right auditory cortex during AHs. Thus our findings support the CAPD model and are consistent with that which postulate reduced prosodic processing during AHs.
authors.affiliation: Mental Health Research Institute, Locked Bag 11, Parkville, Victoria 3052, Australia.
authors.forename: Anusha
authors.initials: A
authors.lastname: Sritharan
authors.forename: Per
authors.initials: P
authors.lastname: Line
authors.forename: Alex
authors.initials: A
authors.lastname: Sergejew
authors.forename: Richard
authors.initials: R
authors.lastname: Silberstein
authors.forename: Gary
authors.initials: G
authors.lastname: Egan
authors.forename: David
authors.initials: D
authors.lastname: Copolov
mesh_terms: D000328:Adult; D001304:Auditory Diseases, Central / Q000209:etiology / Q000503:physiopathology; D004569:Electroencephalography; D005625:Frontal Lobe / Q000503:physiopathology; D006212:Hallucinations / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008954:Models, Biological; D012559:Schizophrenia / Q000150:complications*; D013702:Temporal Lobe / Q000503:physiopathology