Dissociable Functional Brain Networks Associated With Apathy in Subcortical Ischemic Vascular Disease and Alzheimer's Disease.

Sabri Altunkaya,Jir-Jei Yang,Sheng-Min Huang,Min-Chien Tu,Li-Wei Kuo,Yen-Hsuan Hsu,Chien-Yuan Lin

doi:10.3389/fnagi.2021.717037

Abstract

Few studies have investigated differences in functional connectivity (FC) between patients with subcortical ischemic vascular disease (SIVD) and Alzheimer’s disease (AD), especially in relation to apathy. Therefore, the aim of this study was to compare apathy-related FC changes among patients with SIVD, AD, and cognitively normal subjects. The SIVD group had the highest level of apathy as measured using the Apathy Evaluation Scale-clinician version (AES). Dementia staging, volume of white matter hyperintensities (WMH), and the Beck Depression Inventory were the most significant clinical predictors for apathy. Group-wise comparisons revealed that the SIVD patients had the worst level of “Initiation” by factor analysis of the AES. FCs from four resting state networks (RSNs) were compared, and the connectograms at the level of intra- and inter-RSNs revealed dissociable FC changes, shared FC in the dorsal attention network, and distinct FC in the salient network across SIVD and AD. Neuronal correlates for “Initiation” deficits that underlie apathy were explored through a regional-specific approach, which showed that the right inferior frontal gyrus, left middle frontal gyrus, and left anterior insula were the critical hubs. These findings broaden the disconnection theory by considering the effect of FC interactions across multiple RSNs on apathy formation.

Highlights

Apathy is defined as a “lack of motivation that is not attributable to a diminished level of consciousness, cognitive impairment, or emotional stress” (Marin, 1991)
Comparisons between subcortical ischemic vascular disease (SIVD)/Alzheimer’s disease (AD) and normal cognition (NC) groups indicated that intra-resting state networks (RSNs) differences involved higher functional connectivity (FC), whereas inter-RSN differences were of lower FC
Among the inter-RSN connections with lower FC, the SIVD and AD groups had two shared connections compared to the NC group, RIFG—posterior cingulate cortex (PCC) and RIFG— LDLPFC

Summary

Introduction

Apathy is defined as a “lack of motivation that is not attributable to a diminished level of consciousness, cognitive impairment, or emotional stress” (Marin, 1991). Apathy is one of the most common behavioral and psychological symptoms of dementia (Kaufer et al, 2000; Lyketsos et al, 2002), and it can be debilitating when it becomes resistant. Functional Networks for Dementia-Related Apathy to treatment. Such behavioral and cognitive inertia hinders social engagement, and worsens functional disability which inevitably leads to early institutionalization and increased caregiver stress (Landes et al, 2001). Factor analysis by psychological metrics in addition to parceling neuroimaging metrics can provide important clinical information, which could assist in managing apathy with a disease-specific paradigm in addition to a more general concept

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