Altered functional connectivity is related to impaired cognition in left unilateral asymptomatic carotid artery stenosis patients

Shihao He,Tian Li,Rong Wang,Cai Zhang,Yanchang Wei,Ziqi Liu,Ran Duan,Ning Ma

doi:10.1186/s12883-021-02385-4

Abstract

BackgroundAsymptomatic carotid artery stenosis (aCAS) impairs haemodynamic and cognitive functions; however, the relationship between these changes and brain network connectivity remains largely unknown. This study aimed to determine the relationship between functional connectivity and neurocognition in patients with aCAS.MethodsWe compared functional status in 14 patients with aCAS and 15 healthy controls using resting state functional magnetic resonance imaging sequences. The subjects underwent a full range of neuropsychological tests and a graphical theoretical analysis of their brain networks.ResultsCompared with controls, patients with aCAS showed significant decline in neuropsychological functions, particularly short-term memory (word-memory, p = .046 and picture-memory, p = .014). Brain network connectivity was lower in patients with aCAS than in the controls, and the decline of functional connectivity in aCAS patients was mainly concentrated in the left and right inferior frontal gyri, temporal lobe, left cingulate gyrus, and hippocampus. Decreased connectivity between various brain regions was significantly correlated with impaired short-term memory. Patients with aCAS showed cognitive impairment independent of known vascular risk factors for vascular cognitive impairment. The cognitive defects were mainly manifested in the short-term memory of words and pictures.ConclusionsThis study is the first of its kind to identify an association between disruption of functional connections in left carotid stenosis and impairment of short-term memory. The findings suggest that alterations in network connectivity may be an essential mechanism underlying cognitive decline in aCAS patients.Clinical trial registration-URLUnique identifier: 04/06/2019, ChiCTR1900023610.

Highlights

Asymptomatic carotid artery stenosis impairs haemodynamic and cognitive functions; the relationship between these changes and brain network connectivity remains largely unknown
Our results suggest that shortterm memory and other cognitive functions decline in Asymptomatic carotid artery stenosis (aCAS) patients prior to the onset of clinical symptoms, and that changes in brain network connectivity may be associated with cognitive impairment
We further found that five functional connections between the triangular part of the inferior frontal gyrus (AAL no.14) and other brain regions were significantly correlated with short-term memory decline

Summary

Introduction

Asymptomatic carotid artery stenosis (aCAS) impairs haemodynamic and cognitive functions; the relationship between these changes and brain network connectivity remains largely unknown. In the mouse model of chronic cerebral insufficiency, the mice did not develop motor dysfunction, their spatial learning ability through the maze test was reduced and they developed varying degrees of cognitive impairment [4]. These findings suggest that aCAS may not, be asymptomatic. Few studies have investigated whether changes in the brain network are associated with altered cognitive function in patients with severe aCAS. Cerebral hypoperfusion or infarction may be the cause of severe aCAS, the pathophysiological mechanism of brain function and network connectivity changes is still unclear [9,10,11,12]

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