Long longitudinal tract lesion contributes to progression of Alzheimer’s disease

Abstract

AbstractBackgroundThe pattern of degenerative changes in white matter (WM) microstructure and its relationship with cognitive function have not been clarified yet in the course of Alzheimer’s disease (AD). The present research aimed to explore the alterations of WM microstructure and its relationship with clinical features in amnestic mild cognitive(aMCI) and AD patients.MethodNeuropsychological data and diffusion tensor imaging (DTI) images were collected from 28 AD subjects, 31 aMCI subjects, and 27 normal controls (NC). Tract‐based spatial statistics (TBSS) were used to investigate fractional anisotropy (FA) and mean diffusivity (MD) among groups. Relationship between diffusion metrics and cognitive functions was examined. A support vector machine (SVM) classification was performed to determine the discriminative ability of DTI metrics in separating aMCI and AD patients from controls.ResultThe values of diffusion metrics in aMCI group presented intermediately between NC and AD groups. As compared to controls or aMCI patients, AD patients displayed widespread WM lesions, including the inferior longitudinal fasciculus, inferior fronto‐occipital fasciculi, superior longitudinal fasciculus and so on. However, no significant FA/MD differences were detected between NC and aMCI groups. Significant relationships between FA/MD metrics of long longitudinal tract and AVLT‐DR scores were found in aMCI and AD groups, respectively. The accuracy of DTI metrics in differentiating controls and AD patients were highly reached 89% and 85% according to SVM.ConclusionWM microstructure is extensively disrupted in AD. Long longitudinal tract integrity is closely related to memory and would hold potential value for monitoring the course of Alzheimer's disease.