A Longitudinal Study on Resting State Functional Connectivity in Behavioral Variant Frontotemporal Dementia and Alzheimer’s Disease

Abstract

Background/Objective: Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) are the most common types of early-onset dementia. We applied longitudinal resting state functional magnetic resonance imaging (fMRI) to delineate functional brain connections relevant for disease progression and diagnostic accuracy. Methods: We used two-center resting state fMRI data of 20 AD patients (65.1 ± 8.0 years), 12 bvFTD patients (64.7 ± 5.4 years), and 22 control subjects (63.8 ± 5.0 years) at baseline and 1.8-year follow-up. We used whole-network and voxel-based network-to-region analyses to study group differences in functional connectivity at baseline and follow-up, and longitudinal changes in connectivity within and between groups. Results: At baseline, connectivity between paracingulate gyrus and executive control network, between cuneal cortex and medial visual network, and between paracingulate gyrus and salience network was higher in AD compared with controls. These differences were also present after 1.8 years. At follow-up, connectivity between angular gyrus and right frontoparietal network, and between paracingulate gyrus and default mode network was lower in bvFTD compared with controls, and lower compared with AD between anterior cingulate gyrus and executive control network, and between lateral occipital cortex and

Abnormal amplitude of low‐frequency fluctuations and functional connectivity of resting‐state functional magnetic resonance imaging in patients with leukoaraiosis

“…The human insular has an important role in attention, language, speech, working memory, and memory (Kelly et al., ). The increased functional connectivity between insula and SOFG was earlier reported in the Alzheimer's Disease(Balthazar et al., ; Hafkemeijer et al., ). Insula and SOFG play an important role in anterior frontoinsular‐cingulo‐orbitofrontal network often called the salience network which is related with the ability to direct attentional resources and goal‐relevant cognition (Menon, ).…”

OCT in Alzheimer’s disease: thinning of the RNFL and superior hemiretina

“…The precuneus was also described as particularly vulnerable for AD pathology, including cerebral atrophy and amyloid deposition [39]. The axons from the superior retina project via the parietal lobe portion of the optic radiation to the cuneal gyrus of the primary visual cortex, and some authors found decreased longitudinal functional connectivity between the precuneus and other cerebral area networks in AD [40][41][42].…”

Single Subject Classification of Alzheimer’s Disease and Behavioral Variant Frontotemporal Dementia Using Anatomical, Diffusion Tensor, and Resting-State Functional Magnetic Resonance Imaging

“…First, while specific functional network connections were found to deviate between AD and bvFTD patients [12,27,28,60], we hypothesized that restricting our analysis to specific network regions may introduce bias and may unnecessary exclude other regions that show deficits at different stages of the disease [23,24,52,66]. The number of network regions that need to be distinguished to optimally differentiate between dementia-types still needs clarification.…”

“…Functional connectivity measures may inform on dementia state [23][24][25] or dementia progression [23][24][25] even well before clinical or structural differences can be detected [25,26]. Differences in functional connectivity strengths as measured with restingstate functional MRI (rs-fMRI) have been heralded as early and useful markers to differentiate AD and bvFTD patients [27,28].…”