Trajectories of the Hippocampal Subfields Atrophy in the Alzheimer's Disease: A Structural Imaging Study.

Weina Zhao,Ying Han,Changhao Yin,Xuetong Wang,Mengfei He,Shuyu Li

doi:10.3389/fninf.2019.00013

Abstract

BackgroundThe hippocampus and hippocampal subfields have been found to be diversely affected in Alzheimer’s Disease (AD) and early stages of Alzheimer’s disease by neuroimaging studies. However, our knowledge is still lacking about the trajectories of the hippocampus and hippocampal subfields atrophy with the progression of Alzheimer’s disease.ObjectiveTo identify which subfields of the hippocampus differ in the trajectories of Alzheimer’s disease by magnetic resonance imaging (MRI) and to determine whether individual differences on memory could be explained by structural volumes of hippocampal subfields.MethodsFour groups of participants including 41 AD patients, 43 amnestic mild cognitive impairment (aMCI) patients, 35 subjective cognitive decline (SCD) patients and 42 normal controls (NC) received their structural MRI brain scans. Structural MR images were processed by the FreeSurfer 6.0 image analysis suite to extract the hippocampus and its subfields. Furthermore, we investigated relationships between hippocampal subfield volumes and memory test variables (AVLT-immediate recall, AVLT-delayed recall, AVLT-recognition) and the regression model analyses were controlled for age, gender, education and eTIV.ResultsCA1, subiculum, presubiculum, molecular layer and fimbria showed the trend toward significant volume reduction among four groups with the progression of Alzheimer’s disease. Volume of left subiculum was most strongly and actively correlated with performance across AVLT measures.ConclusionThe trend changes in the hippocampus subfields and further illustrates that SCD is the preclinical stage of AD earlier than aMCI. Future studies should aim to associate the atrophy of the hippocampal subfields in SCD with possible conversion to aMCI or AD with longitudinal design.

Highlights

The pathophysiological process of Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by cognitive decline, which is thought to have begun many years before the diagnosis
The patients with subjective cognitive decline (SCD) were diagnosed based on the criteria proposed by Subjective Cognitive Decline Initiative (SCD-I) in 2014 (Jessen et al, 2014), including (1) self-reported experience of persistent decline in memory compared to a previous state; (2) performance within the normal range on Mini-Mental State Examination (MMSE) or Montreal Cognitive Assessment (MoCA); (3) the Clinical Dementia Rating (CDR) score is 0
The patients were diagnosed with amnestic mild cognitive impairment (aMCI) using the Petersen criteria (Petersen, 2004), which have been described in our previous studies (Shu et al, 2018): (a) presence of memory complaint, confirmed by an informant; (b) presence of objective memory impairment measured by MMSE, MoCA and auditory verbal learning test (AVLT); (c) failure reach the standard of dementia; (d) Clinical Dementia Rating Scale (CDR) score of 0.5

Summary

Introduction

The pathophysiological process of Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by cognitive decline, which is thought to have begun many years before the diagnosis. As the preclinical AD, subjective cognitive decline (SCD) have worse cognition than normal controls (NC), while objective examination shows that they have not yet reached the level of amnestic mild cognitive impairment (aMCI) or AD dementia (Molinuevo et al, 2017). The main manifestation of SCD is the decline in memory rather than other domains of cognition. If there are significant interferences in the ability of work or daily activities, cognitive decline progresses onward to the stage of AD dementia (Sperling et al, 2011; Jack et al, 2018). These clinical symptoms are caused by the accumulation of pathology leading to the macrostructural disorder of the brain, of which the hippocampus atrophy is the most obvious. Our knowledge is still lacking about the trajectories of the hippocampus and hippocampal subfields atrophy with the progression of Alzheimer’s disease

Methods

Results

Discussion

Conclusion