Relationship of Corpus Callosum Integrity with Working Memory, Planning, and Speed of Processing in Patients with First-Episode and Chronic Schizophrenia.

Ernest Tyburski,Katarzyna Rek-Owodziń,Magdalena Kerestey,Jerzy Samochowiec,Maksymilian Bielecki,Wojciech Andrusewicz,Katarzyna Waszczuk,Błażej Misiak,Piotr Podwalski,Monika Mak,Adrianna Bober,Piotr Plichta,Piotr Marcinowicz,Krzysztof Wietrzyński,Michał Szelepajło,Krzysztof Rudkowski,Anna Michalczyk,Magdalena Więdłocha,Leszek Sagan,Jolanta Kucharska–Mazur

doi:10.3390/jcm10143158

Abstract

There is a paucity of reports examining the relationship between the integrity of the corpus callosum (CC) and different aspects of cognitive functioning in patients with first-episode (FES) and chronic schizophrenia (CS) simultaneously; furthermore, what results exist are inconclusive. We used diffusion tensor imaging tractography to investigate differences in integrity in five regions of the CC between FES, CS, and healthy controls (HC). Additionally, we analyzed correlations between these regions’ integrity and working memory, planning, and speed of processing. Eighteen patients with FES, 55 patients with CS, and 30 HC took part in the study. We assessed cognitive functions with four tasks from Measurement and Treatment Research to Improve Cognition in Schizophrenia. Patients with CS showed lower fractional anisotropy (FA) in Region 5 (statistical trend) and higher mean diffusivity (MD) in Regions 4 and 5 than HC, and patients with FES had higher MD in Region 3 (statistical trend) than HC. Both clinical groups performed worse on working memory and speed of processing tasks than HC, and patients with CS scored worse than HC on independent planning, and worse than FES and HC on dependent planning. Moreover, in patients with CS, MD in Region 3 was correlated with verbal working memory. Our results suggest that patients with FES and CS are characterized by impaired integrity of the middle and posterior CC, respectively. We confirmed that both clinical groups have cognitive impairments. Moreover, the integrity of the middle CC may influence planning in patients with CS.

Highlights

Cognitive dysfunctions, first described by Kraepelin [1] and Bleuler [2], have been observed in all phases of schizophrenia, from the premorbid period, through the ultrahigh-risk state [3,4], the first episode of psychosis [5,6], and continuing into the chronic course of the disease [7,8]
We found that patients from both clinical groups had disturbances in both visuospatial and verbal working memory as well as in speed of processing
We found that patients with chronic schizophrenia (CS) displayed impairments in both aspects of planning in comparison to healthy controls (HC) and had greater difficulties with planning than patients with FES, independently of speed of processing

Summary

Introduction

First described by Kraepelin [1] and Bleuler [2], have been observed in all phases of schizophrenia, from the premorbid period, through the ultrahigh-risk state [3,4], the first episode of psychosis [5,6], and continuing into the chronic course of the disease [7,8]. The deficits are similar in different phases of disease and affect attention, working memory, executive functions, memory, language, and speed of processing. While many hypotheses have been posited regarding their etiology, it has recently been suggested, following Wernicke’s ideas, that cognitive dysfunctions are due to disconnection across the brain [12,13].

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Methods

Conclusion