Changes of functional brain networks and their relations with cognitive function in patients with end-stage renal disease

Objective To investigate the change patterns of functional brain networks and their relations with cognitive function in patients with end-stage renal disease (ESRD). Methods Sixty-two patients with ESRD (ESRD group), admitted to our hospital from July 2018 to June 2019, and 36 age-, gender-, and education level-matched healthy controls (HC group) were enrolled. Mini-mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Trail Making Test A (TMT-A), TMT-B and Symbol Digit Modalities Test (SDMT) were used to evaluate the cognitive function for all subjects. Resting-state functional magnetic resonance imaging data were acquired; after data preprocessing, the brain functional networks were constructed and the topological parameters were calculated. Statistical methods were used to compare the differences of cognitive function scores and topological parameters between the two groups, and to analyze the correlations between these topological parameters and cognitive function scores in the ESRD group. Results The MMSE, MoCA and SDMT scores of the ESRD group were significantly lower than those of the HC group (P<0.05), and the ESRD group took significantly longer time to complete TMT-A and TMT-B than the HC group (P<0.05). The ESRD group had significantly lower normalized clustering coefficient (γ), small-worldness (σ) and local efficiency (Elocal) values than the HC group (P<0.05). Patients in the ESRD group exhibited significantly decreased nodal efficiency in the paralimbic-limbic network (including the bilateral insula, median cingulate and paracingulate gyri, hippocampus, parahippocampal gyrus, amygdala, temporal pole: superior temporal gyrus, and temporal pole: middle temporal gyrus), right heschl gyrus and left superior temporal gyrus, and exhibited significantly increased nodal efficiency in the visual network (including the right distal-shaped gyrus, bilateral wedge, and left superior and middle occipital gyrus) as compared with the HC group (P< 0.05). In the ESRD group, the area under the curve (AUC) of γ and σwas positively correlated with MoCA scores (r=0.698, P=0.000; r=0.661, P=0.000), and the AUC of Elocal showed positive correlation with MMSE scores (r=0.407, P=0.003). Conclusion Abnormal topological organization of the functional brain networks is revealed in patients with ESRD, which affects the cognitive function of these patients. Key words: End-stage renal disease; Cognitive impairment; Functional brain network; Resting-state functional magnetic resonance imaging; Graph theory