Finding the missing-stimulus mismatch negativity (MMN) in early psychosis: Sex-moderated alterations of MMN to violations of an auditory gestalt

Poster A85, Monday, October 8, 11:30 am - 1:00 pm, Essex Ballroom

Hayley Riel1, Erica Rudolph2, Emma Ells2, Philip Tibbo1, Dean Salisbury3, Derek Fisher2; 1Dalhousie University, 2Mount Saint Vincent University, 3University of Pittsburgh

The mismatch negativity (MMN) is an EEG-derived event-related potential (ERP) thought to specifically index auditory change detection and, more broadly, central auditory function. Patients with chronic schizophrenia exhibit robust MMN deficits, while MMN reduction in first-episode and early-phase psychosis (EP) is significantly less consistent. Traditional two-tone “oddball” MMN measures of sensory information processing may be considered too simple for use in EP in which pathology has not fully progressed, and a paradigm that probes higher order processes may be more appropriate for elucidating auditory change detection deficits. This study investigated whether MMN deficits could be detected in EP patients using an abstract “missing stimulus” pattern paradigm. EEG recordings of 13 EP patients (≤ 5-year duration of illness) and 15 healthy controls (HC) were collected. Preliminary analyses revealed MMN amplitude reductions in EPs, suggesting that these deficits are present very early in the progression of the illness. However, after splitting the EP group into male (n = 8) and female (n = 5) subgroups, we observed this difference was limited to males (male EP < female EP). Specifically, there was a statistical difference between groups at sites F3 (p = .013), FZ (p = .005), F4 (p = .015) and CZ (p = .011), as well as a significant difference in MMN latency (p = .038; males > females). These findings suggest that MMN-indexed auditory change detection is impaired in EP patients, but that biological sex may play a role in moderating the relationship between MMN and EP.

Topic Area: First Episode Psychosis

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