Poster #: 128
Topic: Clinical applications (incl. consciousness)
Thursday, Sep 10, 2015
Event-related potentials demonstrate deficits in auditory Gestalt formation and MMN in schizophrenia
Psychiatry, The University of Pittsburgh School of Medicine, Pittsburgh, United States
Grouping of auditory percepts is necessary for interpretation of patterns. Schizophrenia patients have blunted responses to deviance from an established norm, such as reduced mismatch negativity (MMN). Here we compared auditory event-related potential (ERP) responses to complex patterns between schizophrenia patients (SZ; N=25) and matched healthy controls (HC; N=23). ERPs were measured in an auditory pattern in which the first 6 tones increased in pitch in 500 Hz steps, from 1.5 – 4 kHz, and the last 6 tones decreased in pitch (4 – 1.5 kHz). In 8% of trials, the last 6 tones repeated the increasing pitch pattern of the first 6 tones. Stimuli were presented while participants watched a silent video. We observed a large sustained negativity (SN) throughout the entire duration of each group that returned to baseline following completion of the trial. Relationship between SN and ordinal stimulus position was compared between SZ and HC.SN was sensitive to ordinal stimulus position (p<0.01), with largest responses to first and final tones. HC had greater SN than SZ across the entire trial, though differences were greatest for first and final tones (p<0.001). Additionally, a late MMN-like deviance-related negativity was found between 400-500 ms after stimulus onset that was also larger for HC than SZ (p<0.05). These results suggest stronger set formation in HC than SZ. Deficits in auditory pattern processing may be relevant to clinical issues in SZ, such as conceptual disorganization. Future studies will examine relationships between SN and clinical measures.