Association of cognitive performance and psychological traits with diffusion‐weighted tract metrics in older adults with subjective cognitive decline and mild cognitive impairment

Abstract

AbstractBackgroundSubjective Cognitive Decline (SCD) may represent the earliest clinical manifestation of Alzheimer’s disease (AD) (Jessen et al. 2014). In individuals with SCD and mild cognitive impairment (MCI), changes in white matter (WM) microstructure have been shown using diffusion weighted (DW) imaging (Brueggen et al. 2019). However, it is unknown to which extent these alterations are associated with cognitive and psychological deficits. Thus, this study aims to investigate the relationship between WM tract metrics and cognitive performance as well as psychological traits in pre‐dementia stages of AD.MethodIn total, 88 patients with MCI, 90 individuals with SCD, and 47 healthy controls (mean age 69±7 years) underwent neuropsychological testing and DW magnetic resonance imaging. Selected questionnaires on stress coping, worry, and rumination were included to evaluate the psychological profile of SCD. Fractional Anisotropy (FA) and Mean Diffusivity (MD) from the DW images were obtained for selected WM tracts of interest using the TRACULA pipeline (Yendiki et al. 2011). Composite scores for memory and executive function were calculated. General linear models adjusted for age, sex, education, cardiovascular risk, and group membership were conducted. Due to the exploratory nature of this study, we did not correct for multiple testing.ResultAcross the entire study sample, higher memory performance was associated with DW parameters of the angular bundle of the cingulum (higher FA, p=0.004; lower MD, p=0.019). Higher FA of the anterior thalamic radiation (ATR) was related to a lower memory score (p=0.049). Higher executive function was related to DW metrics of the uncinate fasciculus (UNC) (higher FA, p=0.038; lower MD, p=0.034) and of the ATR (lower MD, p<0.001). Within SCD subjects, MD of the UNC was positively associated with positive stress coping strategies (p=0.005).ConclusionOur findings suggest that higher memory performance and executive functions are associated with favourable tract‐specific DW parameters in pre‐dementia stages of AD. The relationship of higher positive stress coping with WM microstructural alterations in SCD (i.e., increased MD of the UNC) might be explained by psychological compensatory mechanisms in the presence of early WM pathology. Further investigation is needed to elucidate possible clinical implications of these findings.