Altered Dynamic Functional Connectivity in Subcortical Ischemic Vascular Disease With Cognitive Impairment.

Yuanhang Xu,Li Yao,Hui Lu,Junying Zhang,Huajie Shang,Zhiying Long

doi:10.3389/fnagi.2021.758137

Abstract

Subcortical ischemic vascular disease (SIVD) can cause cognitive impairment and affect the static functional connectivity of resting functional magnetic resonance imaging (fMRI). Numerous previous studies have demonstrated that functional connectivities (FCs) fluctuate dynamically over time. However, little is known about the impact of cognitive impairment on brain dynamic functional connectivity (DFC) in SIVD patients with MCI. In the present study, the DFC analysis method was applied to the resting functional magnetic resonance imaging (fMRI) data of 37 SIVD controls (SIVD-Control) without cognitive impairment, 34 SIVD patients with amnestic MCI (SIVD-aMCI) and 30 SIVD patients with nonamnestic MCI (SIVD-naMCI). The results indicated that the cognitive impairment of SIVD mainly reduced the mean dwell time of State 3 with overall strong positive connections. The reduction degree of SIVD-aMCI was larger than that of SIVD-naMCI. The memory/execution function impairment of SIVD also changed the relationship between the mean dwell time of State 3 and the behavioral performance of the memory/execution task from significant to non-significant correlation. Moreover, SIVD-aMCI showed significantly lower system segregation of FC states than SIVD-Control and SIVD-naMCI. The system segregation of State 5 with overall weak connections was significantly positive correlated with the memory performance. The results may suggest that the mean dwell time of State 3 and the system segregation of State 5 may be used as important neural measures of cognitive impairments of SIVD.

Highlights

Cerebral small vessel disease (CSVD) is a disease that causes brain damage due to changes in small vessels in the brain
The results indicated that the presence of amnestic MCI (aMCI) and nonamnestic MCI (naMCI) could cause Subcortical ischemic vascular disease (SIVD) patients to stay in State 3 for less time
This study investigated the impact of cognitive impairment on the dynamic functional connectivity (DFC) of SIVD patients

Summary

Introduction

Cerebral small vessel disease (CSVD) is a disease that causes brain damage due to changes in small vessels in the brain. Subcortical ischemic vascular disease (SIVD) is the typical representative and a more homogeneous subtype of CSVD. It is widespread among elderly individuals with asymptomatic lacunes and subcortical white matter (WM) hyperintensities (Roman et al, 2002). SIVD frequently causes cognitive impairment and dementia (Pantoni, 2010). Altered DFC in SIVD-MCI vascular disease patients with cognitive impairment show cognitive deficits in mental speed, language, executive functioning, visuospatial reasoning and memory (Frisoni et al, 2002; Galluzzi et al, 2005; Seo et al, 2010). SIVD patients could manifest unobvious or even nonexistent cognitive impairment at an early stage, and they may have a high risk of cognitive impairment in the future (Sachdev et al, 2014). Studying the neural correlates of SIVD can advance our understanding of the mechanism through which SIVD contributes to cognitive impairment

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