The corpus callosum in first episode schizophrenia: a diffusion tensor imaging study

Abstract

Background: Neuropathological and imaging studies suggest that corpus callosum abnormalities (CC) are present in schizophrenia, but it remains to be determined whether these abnormalities are present at illness onset. Diffusion tensor imaging (DTI), which is more sensitive than conventional magnetic resonance imaging (MRI) in detecting subtle structural changes in the organisation and integrity of white matter tracts, is an ideal tool to investigate this question. Objective: To determine whether CC abnormalities are present at illness onset in schizophrenia. Methods: Twenty patients (14 men, six women) with first episode schizophrenia and 29 controls (11 men, 18 women) were studied. Both high resolution volumetric T1-weighted images and DTI were acquired. Regions of interest (ROI) were placed in the splenium and genu of the CC and fractional anisotropy (FA) and diffusivity (D) measured. Results: No differences in FA or D were detected in these regions between patients and controls. In women, irrespective of group membership, FA was significantly lower and there was a trend for D to be higher than in men, indicating less barriers to diffusion in females. Conclusion: The negative findings of this study suggest that in the early stages of schizophrenia there is no disruption to the integrity of the CC and raise the possibility that the neuropathological abnormalities may appear later and be progressive, at least in some patients.

White Matter Fibertracking in First-Episode Schizophrenia, Schizoaffective Patients and Subjects at Ultra-High Risk of Psychosis

“…The spread of the FA distribution along the tract was skewed in the patients, which is thought to represent reduced FA in the core of the tract. In accordance with another first-episode study [13] , we found no abnormalities in the genu or splenium of the corpus callosum. In contrast, Cheung et al [16] did find reduced FA in the splenium of the corpus callosum in medication-naive firstepisode patients.…”

Altered Interhemispheric and Temporal Lobe White Matter Microstructural Organization in Severe Chronic Schizophrenia

“…Postmortem studies have shown a genderdiagnosis effect of reduced axonal number (Highley et al, 1999a), oligodendrocyte density loss (Hof et al, 2003), and lower levels of immunoreactivity of oligodendrocyte-associated proteins in the genu of the corpus callosum (Flynn et al, 2003). Diffusion-weighted imaging has been relatively consistent in reporting reduced callosal FA in chronic schizophrenia (Douaud et al, 2007;Koch et al, 2010;Kubicki et al, 2008;Miyata et al, 2010;Mori et al, 2007b;RotarskaJagiela et al, 2008), including during remission (Koch et al, 2010) and less consistently in studies examining individuals at the first episode (Cheung et al, 2008;Gasparotti et al, 2009;Perez-Iglesias et al, 2010b;Peters et al, 2008;Price et al, 2005;Szeszko et al, 2005) or in earlier stages of illness (Davenport et al, 2010;Douaud et al, 2007;Kyriakopoulos and Frangou, 2009). Directly comparing first episode and chronic groups supports more severe changes in FA in the genu of the corpus callosum (Friedman et al, 2008;Kong et al, 2011), the left ILF (Friedman et al, 2008), and ALIC (Bora et al, 2011) in the chronic group including relative to the first episode group.…”

“…Longitudinal studies highlight the progressive nature of these deficits. In WM, a single study of individuals experiencing their first psychotic episode did not detect microstructural changes (as assessed by DTI) in the corpus callosum relative to healthy controls (Price et al, 2005). Studies including both first episode and chronic patients showed that patients with chronic disease had significantly reduced FA compared with controls, reaching only a trend level in first episode patients (Friedman et al, 2008;Kong et al, 2011).…”

Complementary diffusion tensor imaging study of the corpus callosum in patients with first-episode and chronic schizophrenia

“…For example, Pomarol-Clotet and colleagues 28 reported a positive finding in patients with chronic schizophrenia, but Peters and colleagues 9 and Price and colleagues 29 could not detect corpus callosum abnormalities in patients with first-episode schizophrenia, nor in participants at ultra-high risk for psychosis. Most interestingly, Friedman and colleagues 30 conducted a cross-sectional DTI study including patients with firstepisode and chronic schizophrenia and obtained similar findings to those of our current study: less prominent changes in white matter at illness onset that progress in more chronic states of illness.…”