Cerebral microinfarcts affect brain structural network topology in cognitively impaired patients

• Published in: Journal of cerebral blood flow and metabolism Vol. 41; no. 1; pp. 105 - 115
• Main Authors: Zhang, Liwen, Biessels, Geert Jan, Hilal, Saima, Chong, Joanna Su Xian, Liu, Siwei, Shim, Hee Youn, Xu, Xin, Chong, Eddie Jun Yi, Wong, Zi Xuen, Loke, Yng Miin, Venketasubramanian, Narayanaswamy, Yeow, Tan Boon, Chen, Christopher Li-Hsian, Zhou, Juan Helen
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.2021
• Subjects: Original; cognitive impairment no dementia; cognitive impairment; Alzheimer’s disease; cortical cerebral microinfarcts; structural network topology
• ISSN: 0271-678X; 1559-7016
• DOI: 10.1177/0271678X20902187

Cerebral microinfarcts (CMIs), a novel cerebrovascular marker, are prevalent in Alzheimer’s disease (AD) and associated with cognitive impairment. Nonetheless, the underlying mechanism of how CMIs influence cognition remains uncertain. We hypothesized that cortical-CMIs disrupted structural connectivity in the higher-order cognitive networks, leading to cognitive impairment. We analyzed diffusion-MRI data of 92 AD (26 with cortical-CMIs) and 110 cognitive impairment no dementia patients (CIND, 28 with cortical-CMIs). We compared structural network topology between groups with and without cortical-CMIs in AD/CIND, and tested whether structural connectivity mediated the association between cortical-CMIs and cognition. Cortical-CMIs correlated with impaired structural network topology (i.e. lower efficiency/degree centrality in the executive control/dorsal attention networks in CIND, and lower clustering coefficient in the default mode/dorsal attention networks in AD), which mediated the association of cortical-CMIs with visuoconstruction dysfunction. Our findings provide the first in vivo human evidence that cortical-CMIs impair cognition in elderly via disrupting structural connectivity.