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

Murphy

et al. 2016

Schizophrenia Research

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Mismatch negativity (MMN) in response to deviation from physical sound parameters (e.g., pitch, duration) is reduced in individuals with long-term schizophrenia (Sz), suggesting deficits in deviance detection. However, MMN can appear at several time intervals as part of deviance detection. Understanding which part of the processing stream is abnormal in Sz is crucial for understanding MMN pathophysiology. We measured MMN to complex pattern deviants, which have been shown to produce multiple MMNs in healthy controls (HC). Both simple and complex MMNs were recorded from 27 Sz and 27 matched HC. For simple MMN, pitch- and duration-deviants were presented among frequent standard tones. For complex MMN, patterns of five single tones were repeatedly presented, with the occasional deviant group of tones containing an extra sixth tone. Sz showed smaller pitch MMN (p=.009, ~110ms) and duration MMN (p=.030, ~170ms) than healthy controls. For complex MMN, there were two deviance-related negativities. The first (~150ms) was not significantly different between HC and SZ. The second was significantly reduced in Sz (p=.011, ~400ms). The topography of the late complex MMN was consistent with generators in anterior temporal cortex. Worse late MMN in Sz was associated with increased emotional withdrawal, poor attention, lack of spontaneity/conversation, and increased preoccupation. Late MMN blunting in schizophrenia suggests a deficit in later stages of deviance processing. Correlations with negative symptoms measures are preliminary, but suggest that abnormal complex auditory perceptual processes may compound higher-order cognitive and social deficits in the disorder.

Section: Introductionsupporting

confidence: 71%

Abnormal auditory pattern perception in schizophrenia

Murphy

et al. 2016

Schizophrenia Research

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“…On the other hand, pairs of tones that descended in pitch produced a MMN when compared to expected pairs of tones that increased in pitch (Salisbury et al ., ). A missing tone amongst standard groups of six tones produced a smaller MMN in individuals with long‐term schizophrenia (150–200 ms after the expected onset of the tone; Salisbury & McCathern, ) and in recent‐onset patients with schizophrenia (100–250 ms; Rudolph et al ., ). We measured MMN to an extra tone that violated a quantity/number grouping rule in individuals with long‐term schizophrenia (Haigh et al ., ), and found no significant differences between groups in the early MMN, but found significant reductions in the late MMN in schizophrenia (~ 350 ms after the onset of the extra tone), suggesting specific deficits in later deviance processing.…”

Section: Introductionmentioning

confidence: 97%

Mismatch negativity to pitch pattern deviants in schizophrenia

Matteis

et al. 2017

Eur J of Neuroscience

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Simple mismatch negativity (MMN) to infrequent pitch deviants is impaired in individuals with long-term schizophrenia (Sz). The complex MMN elicited by pattern deviance often manifests later after deviant-onset than simple MMN, and can ascertain deficits in abstracting relationships between stimuli. Sz exhibit reduced complex MMN, but so far this has only been measured when deviance detection relies on a grouping rule. We measured MMN to deviants in pitch-based rules to see if MMN is also abnormal in Sz under these conditions. Three experiments were conducted. Twenty-seven Sz and 28 healthy matched controls (HC) participated in Experiments 1 and 2, and 24 Sz and 26 HC participated in Experiment 3. Experiment 1 was a standard pitch MMN task, and Sz showed the expected MMN reduction (~115 ms) to the simple pitch-deviant compared to HC. Experiment 2 comprised standard groups of six tones that ascended in pitch, and deviant groups where the last tone descended in pitch. Complex MMN was late (~510 ms) and significantly blunted in Sz. Experiment 3 comprised standard groups of 12 tones (six tones ascending in pitch followed by six tones descending in pitch, like a scale), and deviant groups containing two repetitions of six ascending tones (the scale restarted midstream). Complex MMN was also late (~460 ms) and significantly blunted in Sz. These results identify a late pitch pattern deviance-related MMN that is deficient in schizophrenia. This suggests specific deficits in later more complex deviance detection in schizophrenia for abstract patterns.

“…Sussman and Gumenyuk (2005) also showed that temporal relationships within tone sets can affect whether tones are grouped as objects. Further, MMN is also elicited when established patterns are violated in auditory groups, such as changes in the number of tones (Salisbury et al, 2012; Van Zuijen et al, 2004, Rudolph et al, 2015), or pitch relationships between tones (Saarinen et al, 1992). Although these studies clearly demonstrate effects of acoustic segmentation, a more direct measure is needed which does not rely on pattern deviation.…”

Section: Introductionmentioning

confidence: 99%

Event-related potentials demonstrate deficits in acoustic segmentation in schizophrenia

Murphy

et al. 2016

Schizophrenia Research

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Segmentation of the acoustic environment into discrete percepts is an important facet of auditory scene analysis (ASA). Segmentation of auditory stimuli into perceptually meaningful and localizable groups is central to ASA in everyday situations; for example, separation of discrete words from continuous sentences when processing language. This is particularly relevant to schizophrenia, where deficits in perceptual organization have been linked to symptoms and cognitive dysfunction. Here we examined event-related potentials in response to grouped tones to elucidate schizophrenia-related differences in acoustic segmentation. We report for the first time in healthy subjects a sustained potential that begins with group initiation and ends with the last tone of the group. These potentials were reduced in schizophrenia, with the greatest differences in responses to first and final tones. Importantly, reductions in sustained potentials in schizophrenia patients were associated with greater negative symptoms and deficits in IQ, working memory, learning, and social cognition. These results suggest deficits in auditory pattern segmentation in schizophrenia may compound deficits in many higher-order facets of the disorder.