PhD Scientific Days 2022

Mental Health Sciences II. (Poster discussion will take place in the Aula during the Coffee Break)

Acoustic and visual mismatch negativity as potential biomarkers in schizophrenia

Text of the abstract

Introduction: Mismatch negativity (MMN) is an event-related potential (ERP), elicited to a visual or acoustic oddball paradigm, in which repeated standard stimuli are disrupted by deviants. The signal latency and amplitude varies according to the stimulus characteristics. The generation of the MMN signal is linked to NMDA-receptor function. MMN is widely investigated in schizophrenia as a potential biomarker.
Aims: Our aim was to examine auditory and visual mismatch negativity in schizophrenia and their correlation with clinical and demographic variables.
Methods: Altogether 39 patients with schizophrenia and 39 healthy controls matched in age, gender, and education were enrolled in the study. EEG was recorded using 64 channels in eight experimental blocks. As acoustic stimuli, we presented 100 and 200 ms sounds. As visual stimuli, 6 and 12 vane windmill patterns were presented to the subjects. Mismatch responses were obtained by subtracting responses to standard from the physically identical deviant stimuli.
Results: In the control group, a significant MMN signal was detected to both acoustic stimuli, in all regions of interest, while no mismatch signal was detected in the patient group. The between group difference was significant. The 12 vane windmill pattern evoked MMN in both study groups but in different regions. The 6 vane windmill pattern evoked MMN only in the patient group. The between group difference was not significant for the visual stimuli. No correlation was found between the MMN amplitude and illness duration, symptom severity (PANSS score) or the antypsychotic medication dosage (in the terms of chlorpromazine (CPZ) equivalent).
Conclusion: According to our results, acoustic stimulus processing tends to be impaired more in schizophrenia compared to visual processing. Therefore, acoustic mismatch negativity is a more promising candidate for biomarker in schizophrenia. Glutamaterg transmission is still promising drug targets in schizophrenia, while MMN is connected to NMDA function, which connection makes it a potential biomarker for monitoring drug efficacy.