The correlation between white matter integrity and pragmatic language processing in first episode schizophrenia

Agnieszka Pawełczyk,Piotr Gębski,Tomasz Pawełczyk,Natalia Żurner,Marta Gawłowska-Sawosz,Emila Łojek

doi:10.1007/s11682-020-00314-6

Abstract

Objective: Higher-order language disturbances could be the result of white matter tract abnormalities. The study explores the relationship between white matter and pragmatic skills in first-episode schizophrenia. Methods: Thirty-four first-episode patients with schizophrenia and 32 healthy subjects participated in a pragmatic language and Diffusion Tensor Imaging study, where fractional anisotropy of the arcuate fasciculus, corpus callosum and cingulum was correlated with the Polish version of the Right Hemisphere Language Battery. Results: The patients showed reduced fractional anisotropy in the right arcuate fasciculus, left anterior cingulum bundle and left forceps minor. Among the first episode patients, reduced understanding of written metaphors correlated with reduced fractional anisotropy of left forceps minor, and greater explanation of written and picture metaphors correlated with reduced fractional anisotropy of the left anterior cingulum. Conclusions: The white matter dysfunctions may underlie the pragmatic language impairment in schizophrenia. Our results shed further light on the functional neuroanatomical basis of pragmatic language use by patients with schizophrenia.

Highlights

Significant positive correlations were found between the results of the Written Metaphors subtest and the fractional anisotropy of right arcuate fasciculus (r = 0.4014, p = 0.019) and the fractional anisotropy of the left forceps minor (r = 0.4908, p = 0.003); these findings indicate that a higher result in the written metaphor understanding test is associated with a higher fractional anisotropy score (“improvement of written metaphors understanding correlates with diffusion restricting to one direction – physiological state of white matter”)
Fractional anisotropy of the anterior part of the left cingulum bundle negatively correlated with the Picture Metaphor Explanation scores (r = −0.4435, p = 0.009) and the WrittenMetaphor Explanation scores (r = −0.3576, p = 0.038), indicating that a higher metaphor explanation test result correlates with a lower fractional anisotropy value (“improvement of metaphors explanation correlates with diffusion being unrestricted in all directions – suggest dysfunctions of white matter”)
Our findings suggest that the structural integrity of the left anterior cingulum bundle and the left forceps minor of the corpus callosum negatively correlates with schizophreniapositive symptoms, and structural integrity of left anterior cingulum bundle correlates with whole psychopathology

Summary

Introduction

These pragmatic aspects of language refer to various process and features of speech: lexicalsemantic processes, understanding and production of vocal non-verbal speech components (prosody), the comprehension of indirect speech acts, non-literal language (idioms, metaphors, irony), discourse comprehension and production, as well as the appreciation of shared knowledge and reflection. They allow the context of interaction to be taken into account, and regulate communicative exchange by a developed and shared system of rules (Łojek 2009; Balconi 2010; Bryan 1995; Bambini et al 2016).

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Discussion

Conclusion