Background
This study aimed to explore the topological alterations of the brain networks of ICU sepsis survivors and their correlation with cognitive impairment.
Methods
16 sepsis survivors from ICU and 19 healthy controls from the community were recruited. Within one month after discharge, neurocognitive tests were administered to assess cognitive performance. Resting-state functional magnetic resonance imaging (rs-fMRI) was acquired and the topological properties of brain networks were measured based on graph theory approaches. Granger causality analysis (GCA) was conducted to quantify effective connectivity (EC) between brain regions showing positive topological alterations and other regions in the brain. The correlations between topological properties and cognitive performance were analyzed.
Results
Sepsis survivors exhibited significant cognitive impairment. At the global level, sepsis survivors showed lower normalized clustering coefficient (γ) and small-worldness (σ). At the local level, degree centrality (DC) and nodal efficiency (NE) decreased in the right orbital part of inferior frontal gyrus (ORBinf.R), NE decreased in the left temporal pole of superior temporal gyrus (TPOsup.L)whereas DC and NE increased in the right cerebellum Crus 2 (CRBLCrus2.R). Regarding directional connection alterations, GCA revealed that EC from left cerebellum 6 (CRBL6.L) to ORBinf.R and EC from TPOsup.L to right cerebellum 1 (CRBLCrus1.R) decreased, whereas EC from right lingual gyrus (LING.R) to TPOsup.L increased. Correlation analysis demonstrated a significant relationship between cerebellar topological alterations and cognitive performance.
Conclusions
Frontal, temporal and cerebellar topological property alterations are involved in the mechanisms of cognitive impairment of ICU sepsis survivors and may serve as biomarkers for early diagnosis.
Trial registration
NCT03946839 (Registered May 10, 2019).
