scholarly journals Lower functional hippocampal redundancy in mild cognitive impairment

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stephanie Langella ◽  
◽  
Muhammad Usman Sadiq ◽  
Peter J. Mucha ◽  
Kelly S. Giovanello ◽  
...  

AbstractWith an increasing prevalence of mild cognitive impairment (MCI) and Alzheimer’s disease (AD) in response to an aging population, it is critical to identify and understand neuroprotective mechanisms against cognitive decline. One potential mechanism is redundancy: the existence of duplicate elements within a system that provide alternative functionality in case of failure. As the hippocampus is one of the earliest sites affected by AD pathology, we hypothesized that functional hippocampal redundancy is protective against cognitive decline. We compared hippocampal functional redundancy derived from resting-state functional MRI networks in cognitively normal older adults, with individuals with early and late MCI, as well as the relationship between redundancy and cognition. Posterior hippocampal redundancy was reduced between cognitively normal and MCI groups, plateauing across early and late MCI. Higher hippocampal redundancy was related to better memory performance only for cognitively normal individuals. Critically, functional hippocampal redundancy did not come at the expense of network efficiency. Our results provide support that hippocampal redundancy protects against cognitive decline in aging.

Neurology ◽  
2020 ◽  
Vol 95 (15) ◽  
pp. e2075-e2085 ◽  
Author(s):  
Tengfei Guo ◽  
Leslie M. Shaw ◽  
John Q. Trojanowski ◽  
William J. Jagust ◽  
Susan M. Landau ◽  
...  

ObjectiveTo compare CSF β-amyloid (Aβ) and florbetapir PET measurements in cognitively unimpaired (CU) elderly adults in order to detect the earliest abnormalities and compare their predictive effect for cognitive decline.MethodsA total of 259 CU individuals were categorized as abnormal (+) or normal (−) on CSF Aβ1-42/Aβ1-40 analyzed with mass spectrometry and Aβ PET measured with 18F-florbetapir. Simultaneous longitudinal measurements of CSF and PET were compared for 39 individuals who were unambiguously Aβ-negative at baseline (CSF−/PET−). We also examined the relationship between baseline CSF/PET group membership and longitudinal changes in CSF Aβ, Aβ PET, and cognition.ResultsThe proportions of individuals in each discordant group were similar (8.1% CSF+/PET− and 7.7% CSF−/PET+). Among baseline Aβ-negative (CSF−/PET−) individuals with longitudinal CSF and PET measurements, a larger proportion subsequently worsened on CSF Aβ (odds ratio 4 [95% confidence interval (CI) 1.1, 22.1], p = 0.035) than Aβ PET over 3.5 ± 1.0 years. Compared to CSF−/PET− individuals, CSF+/PET− individuals had faster (estimate 0.009 [95% CI 0.005, 0.013], p < 0.001) rates of Aβ PET accumulation over 4.4 ± 1.7 years, while CSF−/PET+ individuals had faster (estimate −0.492 [95% CI −0.861, −0.123], p = 0.01) rates of cognitive decline over 4.5 ± 1.9 years.ConclusionsThe proportions of discordant PET and CSF Aβ-positive individuals were similar cross-sectionally. However, unambiguously Aβ-negative (CSF−/PET−) individuals are more likely to show subsequent worsening on CSF than PET, supporting the idea that CSF detects the earliest Aβ changes. In discordant cases, only PET abnormality predicted cognitive decline, suggesting that abnormal Aβ PET changes are a later phenomenon in cognitively normal individuals.


2016 ◽  
Vol 33 (S1) ◽  
pp. S190-S191
Author(s):  
G. Sobreira ◽  
M.A. Aleixo ◽  
C. Moreia ◽  
J. Oliveira

IntroductionDepression and mild cognitive impairment are common among the elderly. Half the patients with late-life depression also present some degree of cognitive decline, making the distinction between these conditions difficult.ObjectivesTo conduct a database review in order to understand the relationship between these entities, and treatment approaches.AimsTo create and implement clinical guidelines at our institution, to evaluate and treat elderly patients presenting with depression and mild cognitive impairment.MethodsA PubMed database search using as keywords “late life depression”, “depression”; “cognitive impairment”; “mild cognitive impairment” and “dementia” between the year 2008 and 2015.ResultsLate-life depression and cognitive impairment are frequent among the elderly (10–20%). Depression is also common in the early stages of dementia decreasing as the cognitive decline progresses. The causal relationship between these entities is not well understood and some authors advocate a multifactorial model (genetic risk factors; neuroendocrine changes; vascular risk factors) and the cognitive impairment of said changes is dependent on the individual's cognitive reserve. Regarding treatment of depression in patients with cognitive impairment, most authors advocate a stepped approach with watchful waiting and then, if symptoms persist, the introduction of pharmacotherapy and psychosocial intervention.ConclusionsThe relationship between cognitive impairment and depression is still not clear and probably multifactorial. The diagnosis of depressive symptoms in patients with severe cognitive impairment can be difficult and most forms of pharmacological treatment in this population are not beneficial, making it important to carefully evaluate the benefits of introducing new medication.Disclosure of interestThe authors have not supplied their declaration of competing interest.


2019 ◽  
Author(s):  
Edward N. Wilson ◽  
Michelle S. Swarovski ◽  
Patricia Linortner ◽  
Marian Shahid ◽  
Abigail J. Zuckerman ◽  
...  

AbstractParkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease (AD) and affects 1% of the population above 60 years old. Although PD commonly manifests with motor symptoms, a majority of patients with PD subsequently develop cognitive impairment which often progresses to dementia, a major cause of morbidity and disability. PD is characterized by α-synuclein accumulation that frequently associates with amyloid beta (Aβ) and tau fibrils, the hallmarks of AD neuropathologic changes; this co-occurrence suggests that onset of cognitive decline in PD may be associated with appearance of pathologic Aβ and/or tau. Recent studies have highlighted the appearance of the soluble form of the Triggering Receptor Expressed on Myeloid cells 2 (sTREM2) receptor in CSF during development of AD. Given the known association of microglial activation with advancing PD, we investigated whether CSF and/or plasma sTREM2 increased with progression to PD dementia. We examined 165 participants consisting of 17 cognitively normal elderly, 45 PD patients with no cognitive impairment, 86 with mild cognitive impairment, and 17 with dementia. Stratification of subjects by CSF Aβ and tau levels revealed that CSF sTREM2 concentrations were elevated in PD subgroups with abnormal tau, but not Aβ, CSF concentration. These findings indicate that CSF sTREM2 could serve as a surrogate immune biomarker of neuronal injury in PD that is associated with cognitive decline.One sentence summaryCSF sTREM2 correlates with CSF tau in PD


2021 ◽  
Author(s):  
Flávia Dahy ◽  
Aline Matos ◽  
Thais Romano ◽  
Rosa Maria Marcusso ◽  
Tatiane Assone ◽  
...  

Background: Central nervous system involvement associated with Coronavirus Disease 2019 (COVID-19) has been reported, including cognitive impairment, even in patients with mild COVID-19. processes. Objective: To assess cognitive decline related to the SARS-CoV-2 infection in patients with neurological disease after COVID-19. Methods: Longitudinal prospective study developed to compare the cognitive performance of patients after COVID-19 based on cognitive complaints. The Addenbrooke´s Cognitive ExaminationRevised (ACE-R), a 100-point test, was applied for investigation, with cut-off score for cognitively normal individuals ≥ 78. Results: Fifty patients were evaluated, 33 women (66%). Thirty-six patients with cognitive complaint (72%), this being the only symptom in 18 (50%), more frequent in women (5:1). Among all patients, the mean score of ACE-R was 80.8 (SD 11) and median of 84. In patients with cognitive complaints, mean of 80.37 (SD 12.2) and median of 84. For the other patients, mean of 81.86 (SD 7.65) and median of 82.5 (p value = 0.9869). Cognitive decline was confirmed in 10/35 (28.57%) of patients with cognitive complaint, and in 4/14 (28.57%) of other patients (exacto de Fisher = 0.8809). Regarding the ACE-R subanalyses, impaired attention and orientation were observed in both groups. Conclusion: Cognitive complaint was not a predictor of cognitive decline, but impairment in attention and orientation were observed in the entire sample.


2020 ◽  
Vol 19 ◽  
pp. 153601212094758 ◽  
Author(s):  
Chanisa Chotipanich ◽  
Monchaya Nivorn ◽  
Anchisa Kunawudhi ◽  
Chetsadaporn Promteangtrong ◽  
Natphimol Boonkawin ◽  
...  

Background: The study aimed to evaluate the appropriate uptake-timing in cognitively normal individuals, mild cognitive impairment (MCI), and Alzheimer’s disease (AD) patients, using 18F-PI 2620 dynamic PET acquisition. Methods: Thirty-four MCI patients, 6 AD patients, and 24 cognitively normal individuals were enrolled in this study. A dynamic 18F-PI 2620 PET study was conducted at 30-75 minutes post-injection in these groups. Co-registration was applied between the dynamic acquisition PET and T1-weighted MRI to delineate various cortical regions. The standardized uptake value ratio (SUVR) was used for quantitative analysis. P-mod software with the Automated Anatomical Labeling (AAL)-merged atlas was employed to generate automatic volumes of interest for 11 brain regions. Results: The curves in most brain regions presented an average SUVR stability at 30-40 minutes post-injection in each group. The appropriate uptake-timing interval of 18F-PI 2620 was 30-75 minutes post injection for AD group and 30-40 minutes post injection for both cognitively normal individuals and MCI groups. Conclusion: Short uptake time around 30-40 minutes post-injection would be more comfortable and convenient for all patients, especially in those with dementia who were unable to stay motionless for long periods of scanning time in the scanner.


2019 ◽  
Vol 9 (2) ◽  
pp. 281-293 ◽  
Author(s):  
Naira Goukasian ◽  
Shai Porat ◽  
Anna Blanken ◽  
David Avila ◽  
Dimitar Zlatev ◽  
...  

We analyzed structural magnetic resonance imaging data from 58 cognitively normal and 101 mild cognitive impairment subjects. We used a general linear regression model to study the association between cognitive performance with hippocampal atrophy and ventricular enlargement using the radial distance method.Bilateral hippocampal atrophy was associated with baseline and longitudinal memory performance. Left hippocampal atrophy predicted longitudinal decline in visuospatial function. The multidomain ventricular analysis did not reveal any significant predictors.


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