Functional and structural alterations of dorsal attention network in preclinical and early‐stage Alzheimer's disease

Abstract

Objectives Subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) are known as the preclinical and early stage of Alzheimer's disease (AD). The dorsal attention network (DAN) is mainly responsible for the “top‐down” attention process. However, previous studies mainly focused on single functional modality and limited structure. This study aimed to investigate the multimodal alterations of DAN in SCD and aMCI to assess their diagnostic value in preclinical and early‐stage AD. Methods Resting‐state functional magnetic resonance imaging (MRI) was carried out to measure the fractional amplitude of low‐frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC). Structural MRI was used to calculate the gray matter volume (GMV) and cortical thickness. Moreover, receiver‐operating characteristic (ROC) analysis was used to distinguish these alterations in SCD and aMCI. Results The SCD and aMCI groups showed both decreased ReHo in the right middle temporal gyrus (MTG) and decreased GMV compared to healthy controls (HCs). Especially in the SCD group, there were increased fALFF and increased ReHo in the left inferior occipital gyrus (IOG), decreased fALFF and increased FC in the left inferior parietal lobule (IPL), and reduced cortical thickness in the right inferior temporal gyrus (ITG). Furthermore, functional and structural alterations in the SCD and aMCI groups were closely related to episodic memory (EM), executive function (EF), and information processing speed (IPS). The combination of multiple indicators of DAN had a high accuracy in differentiating clinical stages. Conclusions Our current study demonstrated functional and structural alterations of DAN in SCD and aMCI, especially in the MTG, IPL, and SPL. Furthermore, cognitive performance was closely related to these significant alterations. Our study further suggested that the combined multiple indicators of DAN could be acted as the latent neuroimaging markers of preclinical and early‐stage AD for their high diagnostic value.

Hyperbolic graph embedding of MEG brain networks to study brain alterations in individuals with subjective cognitive decline

“…We found increased hierarchy, indicated by reduced hyperbolic radii, in the DAN, VAN, and FPN subnetworks for participants experiencing SCD. These findings align with existing evidence of dysfunction in these subnetworks observed in SCD [19], [62], [63], and MCI and AD patients [55], [60], [61]. Furthermore, these three subnetworks were correlated with diminished performance on multiple cognitive assessments.…”

“…At prodromal stages, alterations in the DAN have been consistently observed in patients with MCI [19], [60], [61] and SCD [19], [62], [63]. These alterations have been linked to behavioral deficits in top-down attentional control [61].…”

Pattern and mechanisms of atrophy progression in individuals with a family history of Alzheimer’s disease: a comparative study

“…A meta-analysis on resting-state connectivity has also corroborated the alterations within the DMN and limbic networks (Badhwar et al, 2017). Although altered structural patterns in the dorsal attention network have been reported in AD (Qian et al, 2014) and its early stages (Wu et al, 2023), the relationship between these alterations and the cognitive deficits in the disease remains to be further explored. FHAD-related atrophy has also been localized to the precuneus, a core component of the DMN (Kate et al, 2016).…”

Neuroimaging modalities in the detection of Alzheimer's disease-associated biomarkers

“…Moreover, this pattern of DAN dysfunction has been displayed in the MCI group compared with the CN group between DMN structures. Recent studies have indicated that functional alterations in the DAN could be used as a sensitive marker to forecast the progression from MCI to AD (Pini et al ., 2022 ; Wu et al ., 2022 ; Wu et al ., 2023 ). AD-related decrease of DAN functional connectivity was mainly reported when mean mini-mental state exam score was lower than 14 (Brier et al ., 2012 ; Zhao et al ., 2022 ).…”