Investigation on the Alteration of Brain Functional Network and Its Role in the Identification of Mild Cognitive Impairment

Abstract

Mild cognitive impairment (MCI) is generally regarded as a prodromal stage of Alzheimer's disease (AD). In coping with the challenges caused by AD, we analyzed resting-state functional magnetic resonance imaging data of 82 MCI subjects and 93 normal controls (NCs). The alteration of brain functional network in MCI was investigated on three scales, including global metrics, nodal characteristics, and modular properties. The results supported the existence of small worldness, hubs, and community structure in the brain functional networks of both groups. Compared with NCs, the network altered in MCI over all the three scales. In scale I, we found significantly decreased characteristic path length and increased global efficiency in MCI. Moreover, altered global network metrics were associated with cognitive level evaluated by neuropsychological assessments. In scale II, the nodal betweenness centrality of some global hubs, such as the right Crus II of cerebellar hemisphere (CERCRU2.R) and fusiform gyrus (FFG.R), changed significantly and associated with the severity and cognitive impairment in MCI. In scale III, although anatomically adjacent regions tended to be clustered into the same module regardless of group, discrepancies existed in the composition of modules in both groups, with a prominent separation of the cerebellum and a less localized organization of community structure in MCI compared with NC. Taking advantages of random forest approach, we achieved an accuracy of 91.4% to discriminate MCI patients from NCs by integrating cognitive assessments and network analysis. The importance of the used features fed into the classifier further validated the nodal characteristics of CERCRU2.R and FFG.R could be potential biomarkers in the identification of MCI. In conclusion, the present study demonstrated that the brain functional connectome data altered at the stage of MCI and could assist the automatic diagnosis of MCI patients.

Diagnostic power of resting‐state fMRI for detection of network connectivity in Alzheimer's disease and mild cognitive impairment: A systematic review

“…As a result, 36 articles met our inclusion criteria (13 AD, 14 MCI, and 9 combined AD/MCI articles) and were included in the quantitative synthesis. Thus, the total number of the final included articles was 36 (Balthazar, de Campos, Franco, Damasceno, & Cendes, 2014; Bi, Shu, Sun, & Xu, 2018; Challis et al, 2015; X. Chen et al, 2017; Dai et al, 2012; de Marco et al, 2017; de Vos et al, 2018; Dyrba et al, 2015; Hojjati et al, 2019; Hojjati, Ebrahimzadeh, Khazaee, & Babajani‐Feremi, 2017, 2018; X. Jiang, Zhang, & Zhu, 2014; Jin et al, 2020; Khazaee, Ebrahimzadeh, & Babajani‐Feremi, 2017; Kilian, Bröckel, Overmeyer, Dieterich, & Endrass, 2020; Koch et al, 2012; J. Lee et al, 2015; Y. Li, Wee, Jie, Peng, & Shen, 2014; Lisowska & Rekik, 2019; J. Liu, Pan, Wu, & Wang, 2020; Miao, Wu, Li, Chen, & Yao, 2011; Park et al, 2017; Qian, Zheng, Shang, Zhang, & Zhang, 2018; Qureshi et al, 2019; Schouten et al, 2016; Son, Kim, & Park, 2017; Suk, Wee, Lee, & Shen, 2015; Teipel et al, 2016; Teipel et al, 2017; Wee et al, 2012; Yokoi et al, 2018; Yu et al, 2017; L. Zhang et al, 2020; Y. Zhang, Zhang, Chen, Lee, & Shen, 2017; J. Zhao, Ding, Du, Wang, & Men, 2019; Zheng et al, 2019; Zhu et al, 2014) Overall, the articles had low risk of bias.…”

Disrupted topological organization of resting‐state functional brain networks in cerebral small vessel disease

“…If the core nodes are attacked, the efficiency and stability of network information processing and transmission will be significantly reduced. Given that BC reflects the central roles of nodes in the overall information communication of the networks and has been extensively utilized in the hub analysis of brain networks (Wang, Li, Wang, Xian, & He, 2016; Zhang et al, 2020), we defined the hub regions of brain FC networks by identifying the nodal BC as the key index. We found similar global hub distributions among groups, suggesting that these key regions in brain networks are conserved throughout the development process and that small‐world networks can tolerate developmental alterations or disease (Wen et al, 2017).…”

Differences Changes in Cerebellar Functional Connectivity Between Mild Cognitive Impairment and Alzheimer's Disease: A Seed-Based Approach

“…An increasing number of imaging studies have confirmed that cerebellar Crus II and lobular IX are associated with cognitive networks (32,34,35), particularly with the default mode network (DMN) and fronto-parietal network (FPN) (36)(37)(38). The anterior cerebellum and lobule VIII are associated with movement, whereas the posterior cerebellum (i.e., lobule VI-Crus I, lobule Crus II-VIIB, and lobule IX) are critical for cognitive representation (39)(40)(41).…”