Resting state perfusion in the language network is linked to formal thought disorder and poor functional outcome in schizophrenia

Abstract

Objective: Formal thought disorder (FTD) is a core symptom in schizophrenia. Here, we focus on resting state cerebral blood flow (rCBF) linked to dimensions of FTD.

Methods: We included 47 schizophrenia spectrum patients and 30 age- and gender-matched healthy controls. We assessed FTD with the assessment of thought, language, and communication (TLC) and imaging on a 3T MRI scanner. Within patients, we tested the association of FTD dimensions and in a subgroup (n = 27) the association of functional outcome after 6 months with whole brain rCBF.

Results: Negative FTD was most prominently associated with perfusion within the superior temporal gyrus, while positive FTD was associated with perfusion within the supplementary motor area, and inferior frontal gyrus. Perfusion within the left supramarginal gyrus was associated with social functioning after 6 months.

Conclusions: Distinguishable associations of rCBF with FTD dimensions point to distinct underlying pathophysiology. The location of aberrant perfusion patterns suggests that negative FTD might reflect defective access to semantic memory while positive FTD likely reflects defective suppression of irrelevant information during increased speech production. Finally, the neural correlates of thought block were also predictive of poor functional outcome. Thus, functional outcome and distinct FTD dimensions may share some pathophysiology.

Keywords: formal thought disorder; semantic processing; social functioning; speech production; symptom dimensions.

Figure 1

Positive linear association of severity of overall FTD and resting state perfusion (rCBF) within schizophrenia patients. Increased resting state perfusion (rCBF) bilateral in the temporal lobe was associated with increased severity of overall FTD. Covariates: movement parameters and age. We displayed images on the rendered surface and the sections of the standard MNI‐template. Color bars reflect P‐values of the whole brain analysis.

Figure 2

Positive linear association of severity of negative FTD and resting state perfusion (rCBF) within schizophrenia patients. Increased resting state perfusion (rCBF) bilateral in the temporal lobe was associated with increased severity of negative FTD. Upper panel: whole brain effects; Lower panel: extracted values within significant whole brain clusters. Covariates: movement parameters and age. We displayed images on the sections of the standard MNI‐template. Color bars reflect P‐values of the whole brain analysis.