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Pitch and Duration Mismatch Negativity and Premorbid Intellect in the First Hospitalized Schizophrenia Spectrum
Dean F Salisbury1, Nicola R Polizzotto1,2, Paul G Nestor3
1Clinical Neurophysiology Research Laboratory, Western Psychiatric Institute and Clinic, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
Abstract:
Mismatch negativity (MMN) is a robustly abnormal brainwave in chronically ill schizophrenia that has generated interest as a disease presence biomarker. Reports of MMN reduction in first-episode schizophrenia have been equivocal, raising uncertainty about its reduction at first psychotic break. Here we tested 29 schizophrenia-spectrum participants under 1 year from their first hospitalization for psychosis and 40 age-, gender-, parental socioeconomic status-, and Wechsler Adult Intelligence Scales III Information-matched healthy controls on both pitch and duration MMN. Participants performed a visual checkerboard tracking task while standard (1kHz, 50ms, 80%), pitch-deviant (1.2kHz, 50ms, 10%) and duration-deviant (1kHz, 100ms, 10%) tones were presented over headphones (75 dB) and EEG was recorded. Independent component analysis was used to remove eye movements and visual stimulus processing activity. Groups did not differ in pitch MMN or duration MMN amplitudes. Smaller pitch and duration MMN amplitudes were associated with lower estimates of premorbid intellect in all participants and independently with greater positive symptoms in first hospitalized schizophrenia. Overall MMN reduction was not present in these relatively high functioning individuals at the first episode of schizophrenia, and therefore is not a good disease presence biomarker for this sample. Future research is warranted to determine the degree of MMN reduction at the first episode of psychosis across a greater range of cognitive impairment, the utility of MMN as an indicator of risk or diagnosis, and its role for understanding pathophysiological mechanisms in emerging psychosis.
Insights
Mismatch negativity (MMN) brainwaves were not reduced in first-episode schizophrenia patients. Lower MMN amplitudes correlated with poorer intellect and greater positive symptoms, suggesting MMN is not a reliable biomarker for early psychosis detection.
Area of Science:
- Neuroscience
- Psychiatry
- Biomarker Research
Background:
- Mismatch negativity (MMN) is an abnormal brainwave observed in chronic schizophrenia, considered a potential biomarker for disease presence.
- Previous studies on MMN reduction in first-episode schizophrenia have yielded inconsistent results, creating uncertainty about its utility at the initial psychotic break.
Purpose of the Study:
- To investigate MMN amplitudes (pitch and duration) in individuals within one year of their first hospitalization for psychosis.
- To determine if MMN reduction is a reliable biomarker for disease presence in early-stage schizophrenia spectrum disorders.
Main Methods:
- EEG was recorded from 29 first-episode schizophrenia-spectrum participants and 40 matched healthy controls during a visual tracking task with auditory oddball stimuli.
- Independent component analysis was employed to remove artifacts from eye movements and visual processing.
- Pitch and duration MMN amplitudes were analyzed and correlated with cognitive and symptom measures.
Main Results:
- No significant differences in pitch or duration MMN amplitudes were found between the schizophrenia-spectrum group and healthy controls.
- Smaller MMN amplitudes in both groups were associated with lower premorbid intellect.
- In the schizophrenia group, smaller MMN amplitudes were independently linked to greater positive symptom severity.
Conclusions:
- MMN reduction was not observed in this sample of relatively high-functioning, first-episode schizophrenia patients, indicating it is not a suitable disease presence biomarker in this context.
- Further research is needed to explore MMN in psychosis across diverse cognitive profiles and its potential role in risk assessment, diagnosis, and understanding underlying mechanisms.
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