Prospective Memory and Regional Functional Connectivity in Subcortical Ischemic Vascular Disease.

Xuan-Miao Zhuang,Li-Wei Kuo,Shih-Yen Lin,Min-Chien Tu,Yen-Hsuan Hsu,Jir-Jei Yang

doi:10.3389/fnagi.2021.686040

Abstract

Objectives: Patients with subcortical ischemic vascular disease (SIVD) often have prominent frontal dysfunction. However, it remains unclear how SIVD affects prospective memory (PM), which strongly relies on the frontoparietal network. The present study aimed to investigate PM performance in patients with early stage SIVD as compared to those with Alzheimer's disease (AD) and to older adults with normal cognition, and to explore the neural correlates of PM deficits.Method: Patients with very-mild to mild dementia due to SIVD or AD and normal controls (NC) aged above 60 years were recruited. Seventy-three participants (20 SIVD, 22 AD, and 31 NC) underwent structural magnetic resonance imaging (MRI), cognitive screening tests, and a computerized PM test. Sixty-five of these participants (19 SIVD, 20 AD, and 26 NC) also received resting-state functional MRI.Results: The group with SIVD had significantly fewer PM hits than the control group on both time-based and non-focal event-based PM tasks. Among patients in the very early stage, only those with SIVD but not AD performed significantly worse than the controls. Correlational analyses showed that non-focal event-based PM in SIVD was positively correlated with regional homogeneity in bilateral superior and middle frontal gyri, while time-based PM was not significantly associated with regional homogeneity in any of the regions of interest within the dorsal frontoparietal regions.Conclusions: The findings of this study highlight the vulnerability of non-focal event-based PM to the disruption of regional functional connectivity in bilateral superior and middle frontal gyri in patients with SIVD.

Highlights

Subcortical ischemic vascular disease accounts for a sizable proportion of patients hospitalized for cerebrovascular disease (CVD) (Chui, 2000)
As regional homogeneity (ReHo) has been proven to be sensitive to neurodegenerative processes such as Alzheimer’s disease (AD) (Liu et al, 2008) and subcortical ischemic vascular disease (SIVD) (Tu et al, 2020), we considered that ReHo may serve as an alternative method to detect regional anomalies that underlie prospective memory (PM) failure
Post-hoc analyses showed that the two patient groups performed significantly worse than the normal controls (NC) group, but there was no significant difference between the SIVD and AD groups

Summary

Introduction

Subcortical ischemic vascular disease accounts for a sizable proportion of patients hospitalized for cerebrovascular disease (CVD) (Chui, 2000). Neuropsychological tests have been proven useful for assisting the differential diagnosis between vascular and AD pathology (Kertesz and Clydesdale, 1994; Graham et al, 2004), even in the very early stage (Ingles et al, 2007; Hsu et al, 2015). It remains unclear how SIVD pathology may affect a functionally important cognitive function termed prospective memory (PM), which imposes a heavy load on frontal executive function (Martin et al, 2003; Burgess et al, 2011)

Objectives

Results

Conclusion