id_991. BEYOND LITERAL MEANING: BEHAVIORAL AND EEG EVENT-RELATED POTENTIAL CORRELATES OF FIGURATIVE LANGUAGE COMPREHENSION IMPAIRMENT IN SCHIZOPHRENIA - STUDY ON IDIOMS AND NOVEL METAPHORS.
Ida Żyznowska1, Wojciech Żukowski1, Wiktor Więcławski1, Suvarna Chinta1, Piotr Błądziński2,3, Aneta Kalisz2,3, Andrzej Cechnicki2,3, Krzysztof Walczewski4,5, Łukasz Cichocki4,5, Andrzej Marycz5, Karolina Rataj6, Jakub Szewczyk1, Przemysław Adamczyk1
1 Institute of Psychology, Jagiellonian University, Krakow, Poland
2 Department of Community Psychiatry, Association for the Development of Community Psychiatry and Care, Krakow, Poland
3 Department of Biological and Community Psychiatry, Chair of Psychiatry and Psychotherapy, Jagiellonian University Medical College, Krakow
4 Clinic of Psychiatry, Andrzej Frycz Modrzewski Krakow University, Krakow, Poland
5 Babinski Clinical Hospital, Krakow, Poland
6 Neuroscience of Language Laboratory, Department of Psycholinguistic Studies, Faculty of English, Adam Mickiewicz University, Poznań
INTRODUCTION: Metaphors are crucial for social communication skills, which are reported to be impaired in schizophrenia.
AIM(S): This study investigates neural processing of two types of metaphor: idioms and novel metaphors in schizophrenia and healthy controls using behavioral and EEG-ERP methods.
METHOD(S): In behavior we tested 89 schizophrenia patients (SCH: 55M:34F, age 41±10.0) and 57 healthy controls (CON: 38M:19F, age 41±9.1). EGG results were reported from 50 SCH (35M, 15F; age: 43±9.3) and 42 CON (27M, 15F; age: 42±8.3). Participants performed two punchline-based 1) comprehension and 2) reading tasks. The stimuli comprised 120 short stories in four conditions: idioms (IDI), novel metaphors (NOV), literal (LIT), and meaningless (ABS). To identify between-group differences, we analyzed behavioral scores and two ERP components: N400 and P600. A 64-channel EEG was recorded and preprocessed for ERP analysis using MathWorks MATLAB Automagic. Linear mixed-effects models were fitted for each channel in the 300–500 ms (N400) and 500–700 ms (P600) windows. Group differences in N400 sensitivity to cloze probability (CP) were tested via the group × CP interaction and simple slopes analyses.
RESULTS: SCH showed significantly lower accuracy than controls for LIT (p<0.01) toward a trend for IDI (p=0.06), with no group differences for NOV and ABS items. In EEG, SCH exhibited altered N400 responses to LIT and ABS stories distributed fronto-centrally and to IDI and NOV at posterior regions. P600 differences for IDI and NOV were observed centro-parietally. CP slopes showed reduced sensitivity to word predictability in SCH distributed at frontal and centro-parietal sites.
CONCLUSIONS: To conclude, altered N400/P600 reflect poorer detection of metaphors in schizophrenia. The lower sensitivity to CP indicates less efficient contextual integration of language. We may assume that schizophrenia patients mainly struggle with conventional meanings and misinterpret literal stories as figurative, possibly as a compensatory strategy.
FINANCIAL SUPPORT: This study was supported by the National Science Centre Poland grant no. 2021/41/B/HS6/02967.