scholarly journals Automated Hippocampal Subfield Volumetric Analyses in Atypical Alzheimer’s Disease

2020 ◽  
Vol 78 (3) ◽  
pp. 927-937
Author(s):  
Musa Gabere ◽  
Nha Trang Thu Pham ◽  
Jonathan Graff-Radford ◽  
Mary M. Machulda ◽  
Joseph R. Duffy ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Layer ◽  
Cortical Atrophy ◽  
Regional Patterns ◽  
Pittsburgh Compound B ◽  
Transition Area ◽  
Cell Layers ◽  
Atypical Alzheimer’S Disease ◽  
The Right

Background: Posterior cortical atrophy (PCA) and logopenic progressive aphasia (LPA) are two of the most common variants of atypical Alzheimer’s disease (AD). Both PCA and LPA are associated with relative sparing of hippocampus compared to neocortex, although hippocampal atrophy is observed. It is unclear whether regional patterns of hippocampal subfield involvement differ between PCA and LPA, and whether they differ from typical AD. Objective: To assess volume of specific subfields of the hippocampus in PCA, LPA, and typical AD. Methods: Fifty-nine patients with PCA and 77 patients with LPA were recruited and underwent T1-weighted MRI and Pittsburgh Compound B (PiB) PET at Mayo Clinic. Thirty-six probable AD patients and 100 controls were identified from the Alzheimer’s Disease Neuroimaging Initiative. Hippocampal subfield volumes were calculated using Freesurfer, and volumes were compared between PCA, LPA, AD, and controls using Kruskal-Wallis and Dunn tests. Results: The LPA and PCA groups both showed the most striking abnormalities in CA4, presubiculum, molecular layer of the hippocampus, molecular and granule cell layers of the dentate gyrus, and the hippocampal-amygdala transition area, although atrophy was left-sided in LPA. PCA showed smaller volume of right presubiculum compared to LPA, with trends for smaller volumes of right parasubiculum and fimbria. LPA showed a trend for smaller volumes of left CA1 compared to PCA. The AD group showed smaller volumes of the right subiculum, CA1, and presubiculum compared to LPA. Conclusion: Patterns of hippocampal subfield atrophy differ across the different syndromic variants of AD.

scholarly journals Pathway-Specific Genetic Risk for Alzheimer’s Disease Differentiates Regional Patterns of Cortical Atrophy in Older Adults

2019 ◽  
Author(s):  
Svenja Caspers ◽  
Melanie E Röckner ◽  
Christiane Jockwitz ◽  
Nora Bittner ◽  
Alexander Teumer ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Older Adults ◽  
Alzheimer's Disease ◽  
Genetic Risk ◽  
Anterior Cingulate ◽  
Cortical Atrophy ◽  
Genome Wide Association Studies ◽  
Common Pattern ◽  
Regional Patterns ◽  
Genome Wide

Abstract Brain aging is highly variable and represents a challenge to delimit aging from disease processes. Moreover, genetic factors may influence both aging and disease. Here we focused on this issue and investigated effects of multiple genetic loci previously identified to be associated with late-onset Alzheimer’s disease (AD) on brain structure of older adults from a population sample. We calculated a genetic risk score (GRS) using genome-wide significant single-nucleotide polymorphisms from genome-wide association studies of AD and tested its effect on cortical thickness (CT). We observed a common pattern of cortical thinning (right inferior frontal, left posterior temporal, medial occipital cortex). To identify CT changes by specific biological processes, we subdivided the GRS effect according to AD-associated pathways and performed follow-up analyses. The common pattern from the main analysis was further differentiated by pathway-specific effects yielding a more bilateral pattern. Further findings were located in the superior parietal and mid/anterior cingulate regions representing 2 unique pathway-specific patterns. All patterns, except the superior parietal pattern, were influenced by apolipoprotein E. Our step-wise approach revealed atrophy patterns that partially resembled imaging findings in early stages of AD. Our study provides evidence that genetic burden for AD contributes to structural brain variability in normal aging.

scholarly journals 18F–THK–5351, Fluorodeoxyglucose, and Florbetaben PET Images in Atypical Alzheimer’s Disease: A Pictorial Insight into Disease Pathophysiology

2021 ◽  
Vol 11 (4) ◽  
pp. 465
Author(s):  
Sohee Park ◽  
Minyoung Oh ◽  
Jae Kim ◽  
Jae-Hong Lee ◽  
Young Yoon ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Clinical Symptoms ◽  
Primary Progressive Aphasia ◽  
Clinical Findings ◽  
Cortical Atrophy ◽  
Positron Emission ◽  
Clinical Presentations ◽  
Atypical Alzheimer’S Disease ◽  
Insight Into

The recent advance of positron emission tomography (PET) tracers as biomarkers in Alzheimer’s disease (AD) provides more insight into pathophysiology, preclinical diagnosis, and further therapeutic strategies. However, synergistic processes or interactions between amyloid and tau deposits are still poorly understood. To better understand their relationship in focal brain changes with clinical phenotypes, we focused on region-specific or atypical AD characterized by focal clinical presentations: Posterior cortical atrophy (PCA) and logopenic variant of primary progressive aphasia (lpvPPA). We compared three different PET images with 18F–THK–5351 (tau), 18F–Florbetaben (amyloid beta, Aβ), and 18F–Fluorodeoxyglucose (glucose metabolism) to investigate potential interactions among pathologies and clinical findings. Whereas the amyloid accumulations were widespread throughout the neocortex, tau retentions and glucose hypometabolism showed focal changes corresponding to the clinical features. The distinctly localized patterns were more prominent in tau PET imaging. These findings suggest that tau pathology correlates more closely to the clinical symptoms and the neurodegenerative processes than Aβ pathology in AD.

scholarly journals O3-06-06: Regional patterns of 11 C-PiB uptake and cortical atrophy distinguishes dementia with Lewy bodies from Alzheimer's disease

2010 ◽  
Vol 6 ◽  
pp. S140-S140
Author(s):  
Kejal Kantarci ◽  
Val J. Lowe ◽  
Bradley F. Boeve ◽  
Matthew L. Senjem ◽  
Scott A. Przybelski ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Dementia With Lewy Bodies ◽  
Lewy Bodies ◽  
Cortical Atrophy ◽  
Regional Patterns

scholarly journals Tau and Amyloid Relationships with Resting-state Functional Connectivity in Atypical Alzheimer’s Disease

2020 ◽  
Author(s):  
Irene Sintini ◽  
Jonathan Graff-Radford ◽  
David T Jones ◽  
Hugo Botha ◽  
Peter R Martin ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Functional Connectivity ◽  
Resting State ◽  
Local Network ◽  
Cortical Atrophy ◽  
Resting State Functional Connectivity ◽  
Functional Connections ◽  
Atypical Alzheimer’S Disease ◽  
Network Failures

Abstract The mechanisms through which tau and amyloid-beta (Aβ) accumulate in the brain of Alzheimer’s disease patients may differ but both are related to neuronal networks. We examined such mechanisms on neuroimaging in 58 participants with atypical Alzheimer’s disease (posterior cortical atrophy or logopenic progressive aphasia). Participants underwent Aβ-PET, longitudinal tau-PET, structural MRI and resting-state functional MRI, which was analyzed with graph theory. Regions with high levels of Aβ were more likely to be functional hubs, with a high number of functional connections important for resilience to cascading network failures. Regions with high levels of tau were more likely to have low clustering coefficients and degrees, suggesting a lack of trophic support or vulnerability to local network failures. Regions strongly functionally connected to the disease epicenters were more likely to have higher levels of tau and, less strongly, of Aβ. The regional rate of tau accumulation was associated with tau levels in functionally connected regions, in support of tau accumulation in a functional network. This study elucidates the relations of tau and Aβ to functional connectivity metrics in atypical Alzheimer’s disease, strengthening the hypothesis that the spread of the 2 proteins is driven by different biological mechanisms related to functional networks.

IC-02-05: THE INFLUENCE OF AGE ON REGIONAL [18 F]AV-1451 PET, PITTSBURGH COMPOUND B PET AND MRI ATROPHY IN ATYPICAL ALZHEIMER'S DISEASE

2006 ◽  
Vol 14 (7S_Part_1) ◽  
pp. P6-P7
Author(s):  
Jennifer L. Whitwell ◽  
Jonathan Graff-Radford ◽  
Peter R. Martin ◽  
Matthew L. Senjem ◽  
Christopher G. Schwarz ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Pittsburgh Compound B ◽  
Atypical Alzheimer’S Disease

scholarly journals Contributions of patient and citizen researchers to ‘Am I the right way up?’ study of balance in posterior cortical atrophy and typical Alzheimer’s disease

Dementia ◽  
2018 ◽  
Vol 17 (8) ◽  
pp. 1011-1022 ◽  
Author(s):  
Sebastian J Crutch ◽  
Keir XX Yong ◽  
Amy Peters ◽  
Dilek Ocal ◽  
Diego Kaski ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Support Group ◽  
Scientific Investigation ◽  
Cortical Atrophy ◽  
Posterior Cortical Atrophy ◽  
The Right ◽  
Balance Problems ◽  
Current Report ◽  
Scientific Hypotheses

The current report describes the journey from the sharing of a single, extraordinary experience during a support group conversation to the development of a novel scientific investigation of balance problems in a rarer form of dementia. The story centres around the involvement of people living with or caring for someone with posterior cortical atrophy (often referred to as the visual variant of Alzheimer’s disease) in highlighting hitherto under-appreciated consequences of their condition upon their ability to know ‘Am I the right way up?’. We describe how comments and descriptions of these balance symptoms were collated and communicated, and the involvement of people with posterior cortical atrophy in shaping a series of scientific hypotheses and developing and adapting appropriate experimental materials and procedures. We also reflect more broadly on how we might better recognise, acknowledge and encourage different forms of involvement, and describe several engagement-inspired extensions to the research involving people living with dementia, scientists and artists.

scholarly journals Bayesian model reveals latent atrophy factors with dissociable cognitive trajectories in Alzheimer’s disease

2016 ◽  
Vol 113 (42) ◽  
pp. E6535-E6544 ◽  
Author(s):  
Xiuming Zhang ◽  
Elizabeth C. Mormino ◽  
Nanbo Sun ◽  
Reisa A. Sperling ◽  
Mert R. Sabuncu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Executive Function ◽  
Bayesian Model ◽  
Late Onset ◽  
Temporal Cortex ◽  
Cortical Atrophy ◽  
Future Research ◽  
Dementia Patients ◽  
With Memory

We used a data-driven Bayesian model to automatically identify distinct latent factors of overlapping atrophy patterns from voxelwise structural MRIs of late-onset Alzheimer’s disease (AD) dementia patients. Our approach estimated the extent to which multiple distinct atrophy patterns were expressed within each participant rather than assuming that each participant expressed a single atrophy factor. The model revealed a temporal atrophy factor (medial temporal cortex, hippocampus, and amygdala), a subcortical atrophy factor (striatum, thalamus, and cerebellum), and a cortical atrophy factor (frontal, parietal, lateral temporal, and lateral occipital cortices). To explore the influence of each factor in early AD, atrophy factor compositions were inferred in beta-amyloid–positive (Aβ+) mild cognitively impaired (MCI) and cognitively normal (CN) participants. All three factors were associated with memory decline across the entire clinical spectrum, whereas the cortical factor was associated with executive function decline in Aβ+ MCI participants and AD dementia patients. Direct comparison between factors revealed that the temporal factor showed the strongest association with memory, whereas the cortical factor showed the strongest association with executive function. The subcortical factor was associated with the slowest decline for both memory and executive function compared with temporal and cortical factors. These results suggest that distinct patterns of atrophy influence decline across different cognitive domains. Quantification of this heterogeneity may enable the computation of individual-level predictions relevant for disease monitoring and customized therapies. Factor compositions of participants and code used in this article are publicly available for future research.

scholarly journals Multimodal Discrimination of Alzheimer’s Disease Based on Regional Cortical Atrophy and Hypometabolism

PLoS ONE ◽  
2015 ◽  
Vol 10 (6) ◽  
pp. e0129250 ◽  
Author(s):  
Hyuk Jin Yun ◽  
Kichang Kwak ◽  
Jong-Min Lee ◽  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cortical Atrophy
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