Event-related potentials demonstrate deficits in acoustic segmentation 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.

Section: Discussionmentioning

confidence: 97%

“…Stimuli were the same as those described by Coffman et al . (). Temporal proximity and rhythm were used to form discrete groups of tones, with a SOA within groups of 330 ms and an intertrial interval of 800 ms.…”

Section: Methodsmentioning

confidence: 97%

Mismatch negativity to pitch pattern deviants in schizophrenia

Matteis

et al. 2017

Eur J of Neuroscience

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“…While these correlations are exploratory and require further investigation, they were not significantly correlated with early MMN or simple MMN, suggesting that there is something specific about the late MMN that is reflecting a certain subset of behavioral symptoms. Sz also show other impairments in auditory processing such as the ability to segregate auditory information (Ramage et al, 2012; Weintraub et al, 2012), and in ERP measures of auditory grouping (Coffman et al, 2016), which may be related to the deficits in deviance detection.…”

Section: Discussionmentioning

confidence: 99%

Abnormal auditory pattern perception in schizophrenia

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.

“…This meant that two Sz and three HC were excluded. A 1.5 Hz high-pass filter was then applied (consistent with the analysis of the ASP by Coffman et al, 2016), and was calculated from 330 ms after the first tone in the group to the 330 ms after the last tone in the group. Groups did not significantly differ in the number of epochs included in averages (HC: mean 83.8, std ±11.6; Sz: mean 77.2, std ±16.0; t (43.7)=1.65, p =.105).…”

Section: Methodsmentioning

confidence: 99%

“…The ASP builds over the first several presentations and is disrupted when a deviant tone is presented. The ASP is reduced in individuals with schizophrenia (Coffman et al, 2016), and is related to impairments in measures of neuropsychological functioning, such as working memory, verbal learning, visual learning, and social cognition. Together this suggests specific deficits in novelty detection potentially related to the ability to segment the auditory environment.…”

Section: Introductionmentioning

confidence: 99%

Reduced late mismatch negativity and auditory sustained potential to rule‐based patterns in schizophrenia

Murphy

et al. 2018

Eur J of Neuroscience

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Complex rule-based auditory processing is abnormal in individuals with long-term schizophrenia (SZ), as demonstrated by reduced mismatch negativity (MMN) to deviants in rule-based patterns and reduced auditory sustained potential (ASP) that appears when grouping tones together. Together this suggests deficits later in the auditory processing hierarchy in Sz. Here, MMN and ASP were elicited by deviations from a complex zig-zag pitch pattern that cannot be predicted by simple linear rules. Twenty-seven SZ and 26 matched healthy controls (HC) participated. Frequent groups of patterns contained eight tones that zig-zagged in a two-up one-down pitch-based paradigm. There were two deviant patterns: the final tone was either higher in pitch than expected (creating a jump in pitch) or was repeated. Simple MMN to pitch-deviants among repetitive tones was measured for comparison. Sz exhibited a smaller pitch MMN compared to HC as expected. HC produced a late MMN in response to the repeat and jump-deviant and a larger ASP to the standard group of tones, all of which were significantly blunted in SZ. In Sz, the amplitude of the late complex MMN was related to neuropsychological functioning, whereas ASP was not. ASP and late MMN did not significantly correlate in HC or in Sz, suggesting that they are not dependent on one another and may originate within distinct processing streams. Together this suggests multiple deficits later in the auditory sensory-perceptual hierarchy in Sz, with impairments evident in both segmentation and deviance detection abilities.