scholarly journals Altered Volume and Structural Connectivity of the Hippocampus in Alzheimer’s Disease and Amnestic Mild Cognitive Impairment

2021 ◽  
Vol 13 ◽  
Author(s):  
Feng Feng ◽  
Weijie Huang ◽  
Qingqing Meng ◽  
Weijun Hao ◽  
Hongxiang Yao ◽  
...  

Background: Hippocampal atrophy is a characteristic of Alzheimer’s disease (AD). However, alterations in structural connectivity (number of connecting fibers) between the hippocampus and whole brain regions due to hippocampal atrophy remain largely unknown in AD and its prodromal stage, amnestic mild cognitive impairment (aMCI).Methods: We collected high-resolution structural MRI (sMRI) and diffusion tensor imaging (DTI) data from 36 AD patients, 30 aMCI patients, and 41 normal control (NC) subjects. First, the volume and structural connectivity of the bilateral hippocampi were compared among the three groups. Second, correlations between volume and structural connectivity in the ipsilateral hippocampus were further analyzed. Finally, classification ability by hippocampal volume, its structural connectivity, and their combination were evaluated.Results: Although the volume and structural connectivity of the bilateral hippocampi were decreased in patients with AD and aMCI, only hippocampal volume correlated with neuropsychological test scores. However, positive correlations between hippocampal volume and ipsilateral structural connectivity were displayed in patients with AD and aMCI. Furthermore, classification accuracy (ACC) was higher in AD vs. aMCI and aMCI vs. NC by the combination of hippocampal volume and structural connectivity than by a single parameter. The highest values of the area under the receiver operating characteristic (ROC) curve (AUC) in every two groups were all obtained by combining hippocampal volume and structural connectivity.Conclusions: Our results showed that the combination of hippocampal volume and structural connectivity (number of connecting fibers) is a new perspective for the discrimination of AD and aMCI.

Brain ◽  
2006 ◽  
Vol 129 (11) ◽  
pp. 2867-2873 ◽  
Author(s):  
L. G. Apostolova ◽  
I. D. Dinov ◽  
R. A. Dutton ◽  
K. M. Hayashi ◽  
A. W. Toga ◽  
...  

2021 ◽  
Author(s):  
Sydney Y Schaefer ◽  
Michael Malek-Ahmadi ◽  
Andrew Hooyman ◽  
Jace B. King ◽  
Kevin Duff

Hippocampal atrophy is a widely used biomarker for Alzheimer's disease (AD), but the cost, time, and contraindications associated with magnetic resonance imaging (MRI) limit its use. Recent work has shown that a low-cost upper extremity motor task has potential in identifying AD risk. Fifty-four older adults (15 cognitively unimpaired, 24 amnestic Mild Cognitive Impairment, and 15 AD) completed six motor task trials and a structural MRI. Motor task acquisition significantly predicted bilateral hippocampal volume, controlling for age, sex, education, and memory. Thus, this motor task may be an affordable, non-invasive screen for AD risk and progression.


2021 ◽  
pp. 1-7
Author(s):  
Sydney Y. Schaefer ◽  
Michael Malek-Ahmadi ◽  
Andrew Hooyman ◽  
Jace B. King ◽  
Kevin Duff

Hippocampal atrophy is a widely used biomarker for Alzheimer’s disease (AD), but the cost, time, and contraindications associated with magnetic resonance imaging (MRI) limit its use. Recent work has shown that a low-cost upper extremity motor task has potential in identifying AD risk. Fifty-four older adults (15 cognitively unimpaired, 24 amnestic mild cognitive impairment, and 15 AD) completed six motor task trials and a structural MRI. Several measures of motor task performance significantly predicted bilateral hippocampal volume, controlling for age, sex, education, and memory. Thus, this motor task may be an affordable, non-invasive screen for AD risk and progression.


BMJ Open ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. e049798
Author(s):  
Diyang Lyu ◽  
Taoran Li ◽  
Xuanxin Lyu

IntroductionThe incidence of Alzheimer’s disease (AD) is increasing rapidly, causing a growing burden to health and economic worldwide. Several clinical trials in the past decade failed to find solutions, and there remains a lack of an effective treatment. The evidence suggests that early intervention for neurodegeneration would likely be effective in preventing cognitive decline. Cognitive decline in AD occurs continuously over a long period; however, there remains a lack of simple, rapid and accurate approach for diagnosis of amnestic mild cognitive impairment or subjective cognitive decline due to underlying Alzheimer’s pathology. Resting-state functional MRI (rs-fMRI) determines the functional activities of the human brain non-invasively. The amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF) and regional homogeneity (ReHo) are rs-fMRI indicators with high repeatability. They have been studied as early diagnostic imaging markers for other diseases and may be promising markers also for AD.Methods and analysisThe following electronic literature databases will be searched from inception to December 2021: Medline-Ovid, Medline-PubMed, EMBase-Ovid, Cochrane Central and ClinicalTrials.gov. Two independent reviewers will select studies with eligible criteria, extract data and assess the quality of the original studies with our quality assessment tool individually. Missing data will be requested by sending emails to the corresponding authors. Brain regions will be presented for ALFF/fALFF and ReHo by performing activation likelihood estimation with the Seed-based d Mapping-Permutation of subject images V.6.21 software. Meta-regression will be performed to determine the potential brain regions that may strongly correlate with cognitive decline progression. Subgroup analysis, funnel plot, Egger’s test and sensitivity analysis will be conducted to detect and explain potential heterogeneity.Ethics and disseminationThis study does not require formal ethical approval. The findings will be submitted to a peer-review journal.PROSPERO registration numberCRD42021229009.


2021 ◽  
Vol 33 (S1) ◽  
pp. 83-84
Author(s):  
Supriya Satapathy ◽  
D. Phani Bhushan ◽  
T. Nageshwar Rao ◽  
M. Satyanarayana

Background:Dementia due to probable Alzheimer’s disease (AD) represents between 60 and 80% of all dementias. The total number of estimated AD cases worldwide by 2030 is 65.7 million and 115.4 million by 2050; this represents a twofold population increase in the next 20 years.Magnetic resonance imaging (MRI) has been the primary tool of interest to link hippocampal volume loss with dementia firmly.MRI-based volumetry has been proposed as a promising biomarker.Hippocampal volumetry is useful in discriminating not only cognitively normal individuals from those with dementia but can also differentiate Mild Cognitive Impairment (MCI) from various types of dementia.Research objective:To measure hippocampal volume in various types of dementia. (MMSE) and Activities of daily living (ADL) in patients with dementia.Method:A cross-sectional study conducted for period of one year among 21 patients with Alzheimer’s, vascular dementia, amnestic mild cognitive impairment and 20 healthy age matched controls. MMSE scale was used to stratify patients on cognitive function impairments. ADL scale to assess functional status of the patient ability to perform activities of daily living independently in diverse settings. Hippocampal volume measured using MRI 1.5 T Philips Ingenia, a coronal T1-weighted FFE (Fast Field Echo) 3D sequence.Results:Total Hippocampal volume was reduced by 35% in Alzheimer’s disease, 27% in vascular dementia and 10% in amnestic mild cognitive impairment, compared with control groupConclusions:Moderate positive correlation between mean total hippocampal volume and MMSE scores in patients with dementia which was statistically significant. (P value= 0.001).


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