Differences in Cerebral Structure Associated With Depressive Symptoms in the Elderly With Alzheimer's Disease.

Yue Wu,Qiang Wei,Kai Wang,Xingqi Wu,Yanghua Tian

doi:10.3389/fnagi.2020.00107

Abstract

Background: Alzheimer’s disease (AD) is characterized by global deterioration in multiple cognitive domains. In addition to cognitive impairment, depressive symptoms are common issues that trouble AD patients. The neuroanatomical basis of depressive symptoms in AD patients has yet to be elucidated.Method: Twenty AD patients and 22 healthy controls (HCs) were recruited for the present study. Depressive symptoms in AD patients and HCs were assessed according to the Hamilton Depression Rating Scale (HDRS). Anatomical structural differences were assessed between AD patients and HCs using voxel-based morphometry (VBM) and surface-based morphometry (SBM). Correlation analyses were conducted to investigate relationships between depressive symptoms and structural altered regions. Multiple pattern analysis using linear support vector machine (SVM) was performed in another independent cohort, which was collected from Alzheimer’s Disease Neuroimaging Initiative (ADNI) data and contained 20 AD patients and 20 HCs, to distinguish AD patients from HCs.Results: Compared with HCs, AD patients exhibited global cerebral atrophy in gray matter volume (GMV) and cortical thickness, including frontal, parietal, temporal, occipital, and insular lobes. In addition, insular GMV was negatively correlated with depressive symptoms. Moreover, SVM-based classification achieved an accuracy of 77.5%, a sensitivity of 70%, and a specificity of 85% by leave-one-out cross-validation.Conclusion: GMV of the insula displayed atrophy among AD patients, which is associated with depressive symptoms. Our observations provide a potential neural substrate for analysis to examine the co-occurrence of AD with depressive symptoms.

Highlights

Alzheimer’s disease (AD) is considered as a global public health problem by the World Health Organization (Lane et al, 2018)
The Voxel-based morphometry (VBM) analysis identified that global cerebral regions, including frontal, parietal, insular, temporal, and occipital lobes and subcortical regions displayed more atrophy in the AD group
The gray matter volume (GMV) of insula displayed a significant negative correlation with the score of Hamilton Depression Rating Scale (HDRS) (r = −0.53 and p = 0.015, see Figure 2), which implied further atrophy of the insula, and this atrophy was more severe for the participants with depressive symptoms

Summary

Introduction

Alzheimer’s disease (AD) is considered as a global public health problem by the World Health Organization (Lane et al, 2018). AD, which was first identified by Alois Alzheimer, is characterized by global deterioration in multiple cognitive domains (Petersen, 2004; Rémy et al, 2005; Chi et al, 2014; Chandra et al, 2019) It is the most common cause of dementia worldwide (Ohnishi et al, 2001; Nho et al, 2012; Wachinger et al, 2016; Mrdjen et al, 2019). In addition to the progressive impairment in cognitive areas, neuropsychiatric symptoms (NPS) and behavioral issues are common concerns for AD patients (Engedal et al, 2011; Benoit et al, 2012; Knapskog et al, 2014). The neuroanatomical basis of depressive symptoms in AD patients has yet to be elucidated

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