Interaction of Background Noise and Auditory Hallucinations on Phonemic Mismatch Negativity (MMN) and P3a Processing in Schizophrenia

Abstract

Auditory hallucinations (AHs) are among the cardinal symptoms of schizophrenia (SZ). During the presence of AHs aberrant activity of auditory cortices have been observed, including hyperactivation during AHs alone and hypoactivation when AHs are accompanied by a concurrent external auditory competitor. Mismatch negativity (MMN) and P3a are common ERPs of interest within the study of SZ as they are robustly reduced in the chronic phase of the illness. The present study aimed to explore whether background noise altered the auditory MMN and P3a in those with SZ and treatmentresistant AHs. Methods: MMN and P3a were assessed in 12 hallucinating patients (HPs), 11 nonhallucinating patients (NPs) and 9 healthy controls (HCs) within an auditory oddball paradigm. Standard (P = 0.85) and deviant (P = 0.15) stimuli were presented during three noise conditions: silence (SL), traffic noise (TN), and wide-band white noise (WN). Results: HPs showed significantly greater deficits in MMN amplitude relative to NPs in all background noise conditions, though predominantly at central electrodes. Conversely, both NPs and HPs exhibited significant deficits in P3a amplitude relative to HCs under the SL condition only. Significance: These findings suggest that the presence of AHs may specifically impair the MMN, while the P3a appears to be more generally impaired in SZ. That MMN amplitudes are specifically reduced for HPs during background noise conditions suggests HPs may have a harder time detecting changes in phonemic sounds during situations with external traffic or "real-world" noise compared to NPs.

Pavlovian conditioning-induced hallucinations reduce MMN amplitudes for duration but not frequency deviants

“…Their findings showed an abnormal roving MMN profile for the AH group, while there was no difference between the healthy comparison group and the combined schizophrenia group (with and without AHs). In a similar vein, Francis et al, (2020) found reduced MMNs for hallucinating patients compared to non-hallucinating patients when studying the influence of background noise in auditory processing. They concluded the presence of AHs may specifically impair the MMN.…”

An α7 nAChR approach for the baseline-dependent modulation of deviance detection in schizophrenia: A pilot study assessing the combined effect of CDP-choline and galantamine

“…It has also been shown to predict conversion into psychosis in children at high-risk ( Bodatsch et al, 2011 ; Perez et al, 2014 ). And most recently, treatment-related improvement in MMN measures was shown to be associated with improvements in clinical features (hallucinations; Francis et al., 2020 ) and attention and memory processing ( Javitt et al, 2018 ). Thus, further reinforcing the implication of MMN as a translatable neural biomarker aiding in the development of novel therapeutic methods and pharmaceuticals in SCZ ( Butler et al, 2012 ; Green et al, 2009 ; Nagai et al., 2013 ; Tada et al, 2019 ; Todd et al, 2013 ).…”