Awareness of cognitive decline trajectories in asymptomatic individuals at risk for AD

Background: Lack of awareness of cognitive decline (ACD) is common in late-stage Alzheimer’s disease (AD). Recent studies showed that ACD can also be reduced in the early stages. Methods: We described different trends of evolution of ACD over 3 years in a cohort of memory-complainers and their association to amyloid burden and brain metabolism. We studied the impact of ACD at baseline on cognitive scores’ evolution and the association between longitudinal changes in ACD and in cognitive score. Results: 76.8% of subjects constantly had an accurate ACD (reference class). 18.95% showed a steadily heightened ACD and were comparable to those with accurate ACD in terms of demographic characteristics and AD biomarkers. 4.25% constantly showed low ACD, had significantly higher amyloid burden than the reference class, and were mostly men. We found no overall effect of baseline ACD on cognitive scores’ evolution and no association between longitudinal changes in ACD and in cognitive scores. Conclusions: ACD begins to decrease during the preclinical phase in a group of individuals, who are of great interest and need to be further characterized. Trial registration: The present study was conducted as part of the INSIGHT-PreAD study. The identification number of INSIGHT-PreAD study (ID-RCB) is 2012-A01731-42

Low Cognitive Awareness, but Not Complaint, is a Good Marker of Preclinical Alzheimer's Disease

Subjective cognitive decline (SCD) may result from many conditions, including Alzheimer's disease (AD)

Gray matter network disruptions and regional amyloid beta in cognitively normal adults

The accumulation of amyloid plaques is one of the earliest pathological changes in Alzheimer's disease (AD) and may occur 20 years before the onset of symptoms. Examining associations between amyloid pathology and other early brain changes is critical for understanding the pathophysiological underpinnings of AD. Alterations in gray matter networks might already start at early preclinical stages of AD. In this study, we examined the regional relationship between amyloid aggregation measured with positron emission tomography (PET) and gray matter network measures in elderly subjects with subjective memory complaints. Single-subject gray matter networks were extracted from T1-weigthed structural MRI in cognitively normal subjects (n = 318, mean age 76.1 ± 3.5, 64% female, 28% amyloid positive). Degree, clustering, path length and small world properties were computed. Global and regional amyloid load was determined using [18F]-Florbetapir PET. Associations between standardized uptake value ratio (SUVr) values and network measures were examined using linear regression models. We found that higher global SUVr was associated with lower clustering (Ã\u9f = -0.12, p < 0.05), and small world values (Ã\u9f = -0.16, p < 0.01). Associations were most prominent in orbito- and dorsolateral frontal and parieto-occipital regions. Local SUVr values showed less anatomical variability and did not convey additional information beyond global amyloid burden. In conclusion, we found that in cognitively normal elderly subjects, increased global amyloid pathology is associated with alterations in gray matter networks that are indicative of incipient network breakdown towards AD dementia

Differential default mode network trajectories in asymptomatic individuals at risk for Alzheimer's disease

Introduction:The longitudinal trajectories of functional brain dynamics and the impact of geneticrisk factors in individuals at risk for Alzheimer\u2019s disease are poorly understood.Methods:In a large-scale monocentric cohort of 224 amyloid stratified individuals at risk forAlzheimer\u2019s disease, default mode network (DMN) resting state functional connectivity (FC) wasinvestigated between two serial time points across 2 years.Results:Widespread DMN FC changes were shown in frontal and posterior areas, as well as in theright hippocampus. There were no cross-sectional differences, however, apolipoprotein E\u3b54(APOE\u3b54) carriers demonstrated slower increase in FC in frontal lobes. There was no impact ofindividual brain amyloid load status.Discussion:For the first time, we demonstrated that the pleiotropic biological effect of theAPOE\u3b54allele impacts the dynamic trajectory of the DMN during aging. Dynamic functional biomarkersmay become useful surrogate outcomes for the development of preclinical targeted therapeuticinterventions

Effect of Alzheimer's disease risk and protective factors on cognitive trajectories in subjective memory complainers: An INSIGHT-preAD study

Introduction: Cognitive change in people at risk of Alzheimer's disease (AD) such as subjective memory complainers is highly variable across individuals. Methods: We used latent class growth modeling to identify distinct classes of nonlinear trajectories of cognitive change over 2 years follow-up from 265 subjective memory complainers individuals (age 70 years and older) of the INSIGHT-preAD cohort. We determined the effect of cortical amyloid load, hippocampus and basal forebrain volumes, and education on the cognitive trajectory classes. Results: Latent class growth modeling identified distinct nonlinear cognitive trajectories. Education was associated with higher performing trajectories, whereas global amyloid load and basal forebrain atrophy were associated with lower performing trajectories. Discussion: Distinct classes of cognitive trajectories were associated with risk and protective factors of AD. These associations support the notion that the identified cognitive trajectories reflect different risk for AD that may be useful for selecting high-risk individuals for intervention trials

Association of cerebrospinal fluid α-synuclein with total and phospho-tau181 protein concentrations and brain amyloid load in cognitively normal subjective memory complainers stratified by Alzheimer's disease biomarkers

147siIntroduction Several neurodegenerative brain proteinopathies, including Alzheimer's disease (AD), are associated with cerebral deposition of insoluble aggregates of α-synuclein. Previous studies reported a trend toward increased cerebrospinal fluid (CSF) α-synuclein (α-syn) concentrations in AD compared with other neurodegenerative diseases and healthy controls. Methods The pathophysiological role of CSF α-syn in asymptomatic subjects at risk of AD has not been explored. We performed a large-scale cross-sectional observational monocentric study of preclinical individuals at risk for AD (INSIGHT-preAD). Results We found a positive association between CSF α-syn concentrations and brain β-amyloid deposition measures as mean cortical standard uptake value ratios. We demonstrate positive correlations between CSF α-syn and both CSF t-tau and p-tau181 concentrations. Discussion Animal models presented evidence, indicating that α-syn may synergistically and directly induce fibrillization of both tau and β-amyloid. Our data indicate an association of CSF α-syn with AD-related pathophysiological mechanisms, during the preclinical phase of the disease.partially_openopenVergallo A.; Bun R.-S.; Toschi N.; Baldacci F.; Zetterberg H.; Blennow K.; Cavedo E.; Lamari F.; Habert M.-O.; Dubois B.; Floris R.; Garaci F.; Lista S.; Hampel H.; Audrain C.; Auffret A.; Bakardjian H.; Baldacci F.; Batrancourt B.; Benakki I.; Benali H.; Bertin H.; Bertrand A.; Boukadida L.; Cacciamani F.; Causse V.; Cavedo E.; Cherif Touil S.; Chiesa P.A.; Colliot O.; Dalla Barba G.; Depaulis M.; Dos Santos A.; Dubois B.; Dubois M.; Epelbaum S.; Fontaine B.; Francisque H.; Gagliardi G.; Genin A.; Genthon R.; Glasman P.; Gombert F.; Habert M.O.; Hampel H.; Hewa H.; Houot M.; Jungalee N.; Kas A.; Kilani M.; La Corte V.; Le Roy F.; Lehericy S.; Letondor C.; Levy M.; Lista S.; Lowrey M.; Ly J.; Makiese O.; Masetti I.; Mendes A.; Metzinger C.; Michon A.; Mochel F.; Nait Arab R.; Nyasse F.; Perrin C.; Poirier F.; Poisson C.; Potier M.C.; Ratovohery S.; Revillon M.; Rojkova K.; Santos-Andrade K.; Schindler R.; Servera M.C.; Seux L.; Simon V.; Skovronsky D.; Thiebaut M.; Uspenskaya O.; Vlaincu M.; Aguilar L.F.; Babiloni C.; Baldacci F.; Benda N.; Black K.L.; Bokde A.L.W.; Bonuccelli U.; Broich K.; Bun R.S.; Cacciola F.; Castrillo J.; Cavedo E.; Ceravolo R.; Chiesa P.A.; Colliot O.; Coman C.M.; Corvol J.C.; Cuello A.C.; Cummings J.L.; Depypere H.; Dubois B.; Duggento A.; Durrleman S.; Escott-Price V.; Federoff H.; Ferretti M.T.; Fiandaca M.; Frank R.A.; Garaci F.; Genthon R.; George N.; Giorgi F.S.; Graziani M.; Haberkamp M.; Habert M.O.; Hampel H.; Herholz K.; Karran E.; Kim S.H.; Koronyo Y.; Koronyo-Hamaoui M.; Lamari F.; Langevin T.; Lehericy S.; Lista S.; Lorenceau J.; Mapstone M.; Neri C.; Nistico R.; Nyasse-Messene F.; O'Bryant S.E.; Perry G.; Ritchie C.; Rojkova K.; Rossi S.; Santarnecchi E.; Schneider L.S.; Sporns O.; Toschi N.; Verdooner S.R.; Vergallo A.; Villain N.; Welikovitch L.; Woodcock J.; Younesi E.Vergallo, A.; Bun, R. -S.; Toschi, N.; Baldacci, F.; Zetterberg, H.; Blennow, K.; Cavedo, E.; Lamari, F.; Habert, M. -O.; Dubois, B.; Floris, R.; Garaci, F.; Lista, S.; Hampel, H.; Audrain, C.; Auffret, A.; Bakardjian, H.; Baldacci, F.; Batrancourt, B.; Benakki, I.; Benali, H.; Bertin, H.; Bertrand, A.; Boukadida, L.; Cacciamani, F.; Causse, V.; Cavedo, E.; Cherif Touil, S.; Chiesa, P. A.; Colliot, O.; Dalla Barba, G.; Depaulis, M.; Dos Santos, A.; Dubois, B.; Dubois, M.; Epelbaum, S.; Fontaine, B.; Francisque, H.; Gagliardi, G.; Genin, A.; Genthon, R.; Glasman, P.; Gombert, F.; Habert, M. O.; Hampel, H.; Hewa, H.; Houot, M.; Jungalee, N.; Kas, A.; Kilani, M.; La Corte, V.; Le Roy, F.; Lehericy, S.; Letondor, C.; Levy, M.; Lista, S.; Lowrey, M.; Ly, J.; Makiese, O.; Masetti, I.; Mendes, A.; Metzinger, C.; Michon, A.; Mochel, F.; Nait Arab, R.; Nyasse, F.; Perrin, C.; Poirier, F.; Poisson, C.; Potier, M. C.; Ratovohery, S.; Revillon, M.; Rojkova, K.; Santos-Andrade, K.; Schindler, R.; Servera, M. C.; Seux, L.; Simon, V.; Skovronsky, D.; Thiebaut, M.; Uspenskaya, O.; Vlaincu, M.; Aguilar, L. F.; Babiloni, C.; Baldacci, F.; Benda, N.; Black, K. L.; Bokde, A. L. W.; Bonuccelli, U.; Broich, K.; Bun, R. S.; Cacciola, F.; Castrillo, J.; Cavedo, E.; Ceravolo, R.; Chiesa, P. A.; Colliot, O.; Coman, C. M.; Corvol, J. C.; Cuello, A. C.; Cummings, J. L.; Depypere, H.; Dubois, B.; Duggento, A.; Durrleman, S.; Escott-Price, V.; Federoff, H.; Ferretti, M. T.; Fiandaca, M.; Frank, R. A.; Garaci, F.; Genthon, R.; George, N.; Giorgi, F. S.; Graziani, M.; Haberkamp, M.; Habert, M. O.; Hampel, H.; Herholz, K.; Karran, E.; Kim, S. H.; Koronyo, Y.; Koronyo-Hamaoui, M.; Lamari, F.; Langevin, T.; Lehericy, S.; Lista, S.; Lorenceau, J.; Mapstone, M.; Neri, C.; Nistico, R.; Nyasse-Messene, F.; O'Bryant, S. E.; Perry, G.; Ritchie, C.; Rojkova, K.; Rossi, S.; Santarnecchi, E.; Schneider, L. S.; Sporns, O.; Toschi, N.; Verdooner, S. R.; Vergallo, A.; Villain, N.; Welikovitch, L.; Woodcock, J.; Younesi, E

Effect of Alzheimer's disease risk and protective factors on cognitive trajectories in subjective memory complainers: An INSIGHT‐preAD study

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