Disrupted Structural White Matter Network in Alzheimer’s Disease Continuum, Vascular Dementia, and Mixed Dementia: A Diffusion Tensor Imaging Study

Abstract

Background: Dementia presents a significant burden to patients and healthcare systems worldwide. Early and accurate diagnosis, as well as differential diagnosis of various types of dementia, are crucial for timely intervention and management. However, there is currently a lack of clinical tools for accurately distinguishing between these types. Objective: This study aimed to investigate the differences in the structural white matter (WM) network among different types of cognitive impairment/dementia using diffusion tensor imaging, and to explore the clinical relevance of the structural network. Methods: A total of 21 normal control, 13 subjective cognitive decline (SCD), 40 mild cognitive impairment (MCI), 22 Alzheimer’s disease (AD), 13 mixed dementia (MixD), and 17 vascular dementia (VaD) participants were recruited. Graph theory was utilized to construct the brain network. Results: Our findings revealed a monotonic trend of disruption in the brain WM network (VaD > MixD > AD > MCI > SCD) in terms of decreased global efficiency, local efficiency, and average clustering coefficient, as well as increased characteristic path length. These network measurements were significantly associated with the clinical cognition index in each disease group separately. Conclusion: These findings suggest that structural WM network measurements can be utilized to differentiate between different types of cognitive impairment/dementia, and these measurements can provide valuable cognition-related information.

Structural white matter properties and cognitive resilience to tau pathology

“…Global efficiency is a measure of information transfer efficiency between brain regions. 16 It has been repeatedly associated with cognitive performance in older participants 17 , 18 , 19 and could play a key role in cognitive resilience. 20 As for the association with micro‐structural white matter properties, we tested if free‐water (FW) corrected fractional anisotropy (FA T , where T stands for tissue), FW‐corrected mean diffusivity (MD T ), FW‐corrected radial diffusivity (RD T ), FW‐corrected axial diffusivity (AD T ), and FW index within the tracts of both networks contributed to cognitive resilience.…”