Abnormal organization of white matter networks in patients with subjective cognitive decline and mild cognitive impairment

Abstract

Network analysis has been widely used in studying Alzheimer's disease (AD). However, how the white matter network changes in cognitive impaired patients with subjective cognitive decline (SCD) (a symptom emerging during early stage of AD) and amnestic mild cognitive impairment (aMCI) (a pre-dementia stage of AD) is still unclear. Here, structural networks were constructed respectively based on FA and FN for 36 normal controls, 21 SCD patients, and 33 aMCI patients by diffusion tensor imaging and graph theory. Significantly lower efficiency was found in aMCI patients than normal controls (NC). Though not significant, the values in those with SCD were intermediate between aMCI and NC. In addition, our results showed significantly altered betweenness centrality located in right precuneus, calcarine, putamen, and left anterior cingulate in aMCI patients. Furthermore, association was found between network metrics and cognitive impairment. Our study suggests that the structural network properties might be preserved in SCD stage and disrupted in aMCI stage, which may provide novel insights into pathological mechanisms of AD.

Network Disruption in the Preclinical Stages of Alzheimer’s Disease: From Subjective Cognitive Decline to Mild Cognitive Impairment

“…To the best of our knowledge, the only study to date studying network topology in SCD reported preserved white matter organization in SCD. 33 Interestingly, in their study SCD elders also exhibited intermediate network parameter values between HC and MCI. The larger sample size of our study probably allowed us to detect significant differences accounting for the discrepancies in the results.…”

“…The only study to date addressing this issue employed structural networks to build graph matrices, reporting no differences between healthy elders with and without cognitive concerns. 33 Although from a theoretical perspective graph metrics provide a common framework that allows comparison between networks coming from different types of data, 23 evidence suggests that differences in methodology and relatively small sample sizes may produce divergent results. 16 To the best of our knowledge, this is the first study to date employing graph metrics built from functional data to characterize the evolution of network dynamics throughout the preclinical stages of AD including healthy elders without cognitive concerns (HC), healthy elders with SCD, and MCI patients.…”

Abnormal Rich Club Organization of Structural Network as a Neuroimaging Feature in Relation With the Severity of Primary Insomnia

“…The WM deterministic fiber tracking was terminated when a tracking turn angle was above 45°or the streamline reached a voxel with an fractional anisotropy (FA) < 0.2 between two consecutive voxels (17). We defined the weight of each effective edge between two nodes (i and j) of the WM structure as the product of FN and mean FA along the fiber bundles, and normalized by the average volume of two connecting nodes (w i j = FN * FA/volume) as previous studies described (18,19). Finally, a weighted matrix of 90 × 90 structural network was constructed for each subject.…”

Visual Attention Performances and Related Cerebral Microstructural Integrity Among Subjects With Subjective Cognitive Decline and Mild Cognitive Impairment

“…Some DTI studies identified widespread white matter microstructural changes in SCD subjects evidenced by certain DTI parameters modification (Selnes et al, 2012 ). Others concluded that although SCD subjects displayed a trend of intermediate stage between normal ageing and MCI, the structural network during SCD stage was relatively preserved (Wang X. N. et al, 2016 ). Interestingly, still some other study revealed no significant changes of white matter integrity between normal ageing and SCD (Kiuchi et al, 2014 ).…”