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Linking self-perceived cognitive functioning questionnaires using item response theory: The subjective cognitive decline initiative. Neuropsychology 2023; 37:463-499. [PMID: 37276136 PMCID: PMC10564559 DOI: 10.1037/neu0000888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023] Open
Abstract
OBJECTIVE Self-perceived cognitive functioning, considered highly relevant in the context of aging and dementia, is assessed in numerous ways-hindering the comparison of findings across studies and settings. Therefore, the present study aimed to link item-level self-report questionnaire data from international aging studies. METHOD We harmonized secondary data from 24 studies and 40 different questionnaires with item response theory (IRT) techniques using a graded response model with a Bayesian estimator. We compared item information curves to identify items with high measurement precision at different levels of the self-perceived cognitive functioning latent trait. Data from 53,030 neuropsychologically intact older adults were included, from 13 English language and 11 non-English (or mixed) language studies. RESULTS We successfully linked all questionnaires and demonstrated that a single-factor structure was reasonable for the latent trait. Items that made the greatest contribution to measurement precision (i.e., "top items") assessed general and specific memory problems and aspects of executive functioning, attention, language, calculation, and visuospatial skills. These top items originated from distinct questionnaires and varied in format, range, time frames, response options, and whether they captured ability and/or change. CONCLUSIONS This was the first study to calibrate self-perceived cognitive functioning data of geographically diverse older adults. The resulting item scores are on the same metric, facilitating joint or pooled analyses across international studies. Results may lead to the development of new self-perceived cognitive functioning questionnaires guided by psychometric properties, content, and other important features of items in our item bank. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
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Association of the Informant-Reported Memory Decline With Cognitive and Brain Deterioration Through the Alzheimer Clinical Continuum. Neurology 2023:WNL.0000000000207338. [PMID: 37085328 DOI: 10.1212/wnl.0000000000207338] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 03/09/2023] [Indexed: 04/23/2023] Open
Abstract
BACKGROUND AND OBJECTIVES Studies are sparse regarding the association between the informant-reported subjective memory decline (informant-report) and Alzheimer's disease (AD) biomarkers. This study thus aimed at determining the clinical relevance of the informant-report throughout the AD clinical continuum, by assessing its specific relationships with amyloid deposition, cognition and neurodegeneration. METHODS Participants from the Imagerie Multimodale de la maladie d'Alzheimer à un stade Précoce (IMAP+) primary cohort and from the Alzheimer's Disease Neuroimaging Initiative (ADNI) replication cohort were included; all underwent multimodal neuroimaging and neuropsychological assessments. Follow-up data of IMAP+ participants over up to 36 months were also used for longitudinal analyses. The informant-report was measured respectively with the Cognitive Difficulties Scale (IMAP+) and Everyday Cognition (ADNI). General linear models were used to assess the cross-sectional associations between the informant-report and amyloid-PET, cognitive performances, and neurodegeneration (atrophy and hypometabolism) in Alzheimer's-signature areas; while longitudinal links were assessed in IMAP+ with linear mixed-effects models. RESULTS 110 IMAP+ participants were included, including 32 cognitively unimpaired elders (controls, age: 70.91±6.57, female:50%), 25 patients with subjective cognitive decline (SCD, 65.88±6.64, 40%), 35 with mild cognitive impairment (MCI, 72.49±7.5, 34%) and 18 with Alzheimer's-type dementia (AD dementia, 68.17±8.59, 28%). 731 ADNI participants were included, including 157 controls (74.21±5.95, 55%), 84 SCD (72.00±5.41, 63%), 369 MCI (71.84±7.4, 44%) and 121 AD dementia (74.29±7.75, 40%). In IMAP+, higher informant-report strongly correlated to greater amyloid-PET specifically in MCI patients (β=0.48, p=.003), and to lower cognitive performance in SCD (global cognition, β=-0.41, p=.04) and MCI patients (memory, β=-0.37, p=.03). Findings in MCI patients were replicated in ADNI (amyloid-PET, β=0.25, p<.001; memory, β=-0.22, p<.001), and extended to neurodegeneration in AD signature areas (β=-0.2, p<.001). Longitudinal analyses in IMAP+ showed links with global cognitive decline over time in MCI (est. -0.74, SE 0.26, p=.005) and in SCD (est. -0.36, SE 0.26, p=.02) patients where higher baseline informant-report also predicted increased amyloid-PET over time (est. 0.008, SE 0.003, p=.02). DISCUSSION Altogether, our findings suggest that the informant-report is particularly relevant in MCI patients where it strongly relates to higher amyloid-PET, indicative of impairment due-to-AD. TRIAL REGISTRATION INFORMATION ClinicalTrials.gov Identifier: NCT01638949.
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Evaluation of tau deposition using 18F-PI-2620 PET in MCI and early AD subjects—a MissionAD tau sub-study. Alzheimers Res Ther 2022; 14:105. [PMID: 35897078 PMCID: PMC9327167 DOI: 10.1186/s13195-022-01048-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/11/2022] [Indexed: 11/10/2022]
Abstract
Background The ability of 18F-PI-2620 PET to measure the spatial distribution of tau pathology in Alzheimer’s disease (AD) has been demonstrated in previous studies. The objective of this work was to evaluate tau deposition using 18F-PI-2620 PET in beta-amyloid positive subjects with a diagnosis of mild cognitive impairment (MCI) or mild AD dementia and characterize it with respect to amyloid deposition, cerebrospinal fluid (CSF) assessment, hippocampal volume, and cognition. Methods Subjects with a diagnosis of MCI due to AD or mild AD dementia and a visually amyloid-positive 18F-florbetaben PET scan (n=74, 76 ± 7 years, 38 females) underwent a baseline 18F-PI-2620 PET, T1-weighted magnetic resonance imaging (MRI), CSF assessment (Aβ42/Aβ40 ratio, p-tau, t-tau) (n=22) and several cognitive tests. A 1-year follow-up 18F-PI-2620 PET scans and cognitive assessments were done in 15 subjects. Results Percentage of visually tau-positive scans increased with amyloid-beta deposition measured in 18F-florbetaben Centiloids (CL) (7.7% (<36 CL), 80% (>83 CL)). 18F-PI-2620 standardized uptake value ratio (SUVR) was correlated with increased 18F-florbetaben CL in several regions of interest. Elevated 18F-PI-2620 SUVR (fusiform gyrus) was associated to high CSF p-tau and t-tau (p=0.0006 and p=0.01, respectively). Low hippocampal volume was associated with increased tau load at baseline (p=0.006 (mesial temporal); p=0.01 (fusiform gyrus)). Significant increases in tau SUVR were observed after 12 months, particularly in the mesial temporal cortex, fusiform gyrus, and inferior temporal cortex (p=0.04, p=0.047, p=0.02, respectively). However, no statistically significant increase in amyloid-beta load was measured over the observation time. The MMSE (Recall score), ADAS-Cog14 (Word recognition score), and CBB (One-card learning score) showed the strongest association with tau deposition at baseline. Conclusions The findings support the hypothesis that 18F-PI-2620 PET imaging of neuropathologic tau deposits may reflect underlying neurodegeneration in AD with significant correlations with hippocampal volume, CSF biomarkers, and amyloid-beta load. Furthermore, quantifiable increases in 18F-PI-2620 SUVR over a 12-month period in regions with early tau deposition are consistent with the hypothesis that cortical tau is associated with cognitive impairment. This study supports the utility of 18F-PI-2620 PET to assess tau deposits in an early AD population. Quantifiable tau load and its corresponding increase in early AD cases could be a relevant target engagement marker in clinical trials of anti-amyloid and anti-tau agents. Trial registration Data used in this manuscript belong to a tau PET imaging sub-study of the elenbecestat MissionAD Phase 3 program registered in ClinicalTrials.gov (NCT02956486; NCT03036280). Supplementary Information The online version contains supplementary material available at 10.1186/s13195-022-01048-x.
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Plasma Levels of Tissue-Type Plasminogen Activator (tPA) in Normal Aging and Alzheimer's Disease: Links With Cognition, Brain Structure, Brain Function and Amyloid Burden. Front Aging Neurosci 2022; 14:871214. [PMID: 35747448 PMCID: PMC9211060 DOI: 10.3389/fnagi.2022.871214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 04/20/2022] [Indexed: 11/13/2022] Open
Abstract
Tissue-type plasminogen activator (tPA) is a protease known for its fibrinolytic action but is also involved in physiological and pathophysiological aging processes; including amyloid elimination and synaptic plasticity. The aim of the study was to investigate the role of tPA in cognitive and brain aging. Therefore, we assessed the links between tPA plasma concentration and cognition, structural MRI, FDG-PET and Flobetapir-PET neuroimaging in 155 cognitively unimpaired adults (CUA, aged 20-85 years old) and 32 patients with Alzheimer's disease (ALZ). A positive correlation was found between tPA and age in CUA (p < 0.001), with males showing higher tPA than females (p = 0.05). No significant difference was found between ALZ patients and cognitively unimpaired elders (CUE). Plasma tPA in CUA negatively correlated with global brain volume. No correlation was found with brain FDG metabolism or amyloid deposition. Age-related tPA changes were associated to changes in blood pressure, glycemia and body mass index. Within the ALZ patients, tPA didn't correlate with any cognitive or neuroimaging measures, but only with physiological measures. Altogether our study suggests that increased tPA plasma concentration with age is related to neuronal alterations and cardiovascular risk factors.
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Informant‐reported subjective cognitive decline is specifically relevant in MCI patients: Association with cognition, amyloid deposition and neurodegeneration. Alzheimers Dement 2021. [DOI: 10.1002/alz.053577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Subjective cognitive decline: opposite links to neurodegeneration across the Alzheimer's continuum. Brain Commun 2021; 3:fcab199. [PMID: 34704027 PMCID: PMC8421692 DOI: 10.1093/braincomms/fcab199] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/29/2021] [Accepted: 07/09/2021] [Indexed: 11/13/2022] Open
Abstract
Subjective memory decline is associated with neurodegeneration and increased risk of cognitive decline in participants with no or subjective cognitive impairment, while in patients with mild cognitive impairment or Alzheimer's-type dementia, findings are inconsistent. Our aim was to provide a comprehensive overview of subjective memory decline changes, relative to objective memory performances, and of their relationships with neurodegeneration, across the clinical continuum of Alzheimer's disease. Two hundred participants from the Imagerie Multimodale de la maladie d'Alzheimer à un stade Précoce (IMAP+) primary cohort and 731 participants from the Alzheimer's Disease Neuroimaging Initiative (ADNI) replication cohort were included. They were divided into four clinical groups (Imagerie Multimodale de la maladie d'Alzheimer à un stade Précoce/Alzheimer's Disease Neuroimaging Initiative): controls (n = 67/147, age: 60-84/60-90, female: 54/55%), patients with subjective cognitive decline (n = 30/84, age: 54-84/65-80, female: 44/63%), mild cognitive impairment (n = 50/369, age: 58-86/55-88, female: 45/44%) or Alzheimer's-type dementia (n = 36/121, age: 51-86/61-90, female: 41/41%). Subjective and objective memory scores, and their difference (i.e. delta score reflecting memory awareness), were compared between groups. Then, voxelwise relationships between subjective memory decline and neuroimaging measures of neurodegeneration [atrophy (T1-MRI) and hypometabolism (18F-fluorodeoxyglucose-PET)] were assessed across clinical groups and the interactive effect of the level of cognitive impairment within the entire sample was assessed. Analyses were adjusted for age, sex and education, and repeated including only the amyloid-positive participants. In Imagerie Multimodale de la maladie d'Alzheimer à un stade Précoce, the level of subjective memory decline was higher in all patient groups (all P < 0.001) relative to controls, but similar between patient groups. In contrast, objective memory deficits progressively worsened from the subjective cognitive decline to the dementia group (all P < 0.001). Accordingly, the delta score showed a progressive decline in memory awareness across clinical groups (all P < 0.001). Voxelwise analyses revealed opposite relationships between the subjective memory decline score and neurodegeneration across the clinical continuum. In the earliest stages (i.e. patients with subjective cognitive decline or Mini Mental State Examination > 28), greater subjective memory decline was associated with increased neurodegeneration, while in later stages (i.e. patients with mild cognitive impairment, dementia or Mini Mental State Examination < 27) a lower score was related to more neurodegeneration. Similar findings were recovered in the Alzheimer's Disease Neuroimaging Initiative replication cohort, with slight differences according to the clinical group, and in the amyloid-positive subsamples. Altogether, our findings suggest that the subjective memory decline score should be interpreted differently from normal cognition to dementia. Higher scores might reflect greater neurodegeneration in earliest stages, while in more advanced stages lower scores might reflect decreased memory awareness, i.e. more anosognosia associated with advanced neurodegeneration.
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Early detection of amyloid load using 18F-florbetaben PET. ALZHEIMERS RESEARCH & THERAPY 2021; 13:67. [PMID: 33773598 PMCID: PMC8005243 DOI: 10.1186/s13195-021-00807-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 03/10/2021] [Indexed: 03/26/2023]
Abstract
BACKGROUND A low amount and extent of Aβ deposition at early stages of Alzheimer's disease (AD) may limit the use of previously developed pathology-proven composite SUVR cutoffs. This study aims to characterize the population with earliest abnormal Aβ accumulation using 18F-florbetaben PET. Quantitative thresholds for the early (SUVRearly) and established (SUVRestab) Aβ deposition were developed, and the topography of early Aβ deposition was assessed. Subsequently, Aβ accumulation over time, progression from mild cognitive impairment (MCI) to AD dementia, and tau deposition were assessed in subjects with early and established Aβ deposition. METHODS The study population consisted of 686 subjects (n = 287 (cognitively normal healthy controls), n = 166 (subjects with subjective cognitive decline (SCD)), n = 129 (subjects with MCI), and n = 101 (subjects with AD dementia)). Three categories in the Aβ-deposition continuum were defined based on the developed SUVR cutoffs: Aβ-negative subjects, subjects with early Aβ deposition ("gray zone"), and subjects with established Aβ pathology. RESULTS SUVR using the whole cerebellum as the reference region and centiloid (CL) cutoffs for early and established amyloid pathology were 1.10 (13.5 CL) and 1.24 (35.7 CL), respectively. Cingulate cortices and precuneus, frontal, and inferior lateral temporal cortices were the regions showing the initial pathological tracer retention. Subjects in the "gray zone" or with established Aβ pathology accumulated more amyloid over time than Aβ-negative subjects. After a 4-year clinical follow-up, none of the Aβ-negative or the gray zone subjects progressed to AD dementia while 91% of the MCI subjects with established Aβ pathology progressed. Tau deposition was infrequent in those subjects without established Aβ pathology. CONCLUSIONS This study supports the utility of using two cutoffs for amyloid PET abnormality defining a "gray zone": a lower cutoff of 13.5 CL indicating emerging Aβ pathology and a higher cutoff of 35.7 CL where amyloid burden levels correspond to established neuropathology findings. These cutoffs define a subset of subjects characterized by pre-AD dementia levels of amyloid burden that precede other biomarkers such as tau deposition or clinical symptoms and accelerated amyloid accumulation. The determination of different amyloid loads, particularly low amyloid levels, is useful in determining who will eventually progress to dementia. Quantitation of amyloid provides a sensitive measure in these low-load cases and may help to identify a group of subjects most likely to benefit from intervention. TRIAL REGISTRATION Data used in this manuscript belong to clinical trials registered in ClinicalTrials.gov ( NCT00928304 , NCT00750282 , NCT01138111 , NCT02854033 ) and EudraCT (2014-000798-38).
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Quantitative thresholds for
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F‐florbetaben PET for the detection of low amyloid load. Alzheimers Dement 2020. [DOI: 10.1002/alz.042933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Distinct relationships of self‐reported subjective memory decline to neurodegeneration across the Alzheimer's clinical continuum. Alzheimers Dement 2020. [DOI: 10.1002/alz.040780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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The role of metamemory on cognitive complaints in cancer patients. Brain Behav 2020; 10:e01545. [PMID: 32154659 PMCID: PMC7177574 DOI: 10.1002/brb3.1545] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 11/21/2019] [Accepted: 12/23/2019] [Indexed: 11/07/2022] Open
Abstract
OBJECTIVE Although cancer patients frequently report cognitive disturbances, it is commonly asserted a lack of association between cognitive complaints and neuropsychological test performances. Our goal was to better understand the relationships between subjective and objective cognitive scores through a metamemory monitoring assessment. METHODS Sixty cancer patients currently treated by chemotherapy and/or targeted therapy, and 30 healthy controls (HC) were included. Cognitive complaint was assessed by FACT-cog, QAM and DEX questionnaires. One or more z-scores ≤-1.65 among these three questionnaires defined the presence of cognitive complaints. Objective cognitive performances assessed episodic memory, processing speed and executive functions/working memory (ESR paradigm, TMT, Stroop, n-back). Metamemory was assessed with a Judgment of Learning (JOL) task. RESULTS Patients with cognitive complaints had significantly more depressive and anxiety symptoms (ps < .004), and lower performances on several cognitive tests (ps < .05) than both patients without complaints and HC. More specifically, analyses of the metamemory scores revealed that HC gave significantly more overestimations ("Yes" judgment and incorrect recall) than patients with cognitive complaints (p = .036). For these patients, JOL scores correlated positively with executive functioning (ps < .01). CONCLUSION Metamemory monitoring seems to be well-preserved during cancer. What is more, patients make less overestimation than HC, and they do not underestimate their memory. An accurate self-estimation of memory abilities in cancer patients, particularly those with mild cognitive deficits, may play an adaptive function. Our results suggest that the discrepancy frequently reported between cognitive complaints and objective cognitive scores may not be related to metamemory monitoring dysfunction.
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Tau PET imaging with 18F-PI-2620 in Patients with Alzheimer Disease and Healthy Controls: A First-in-Humans Study. J Nucl Med 2019; 61:911-919. [PMID: 31712323 DOI: 10.2967/jnumed.119.236224] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/04/2019] [Indexed: 12/15/2022] Open
Abstract
18F-PI-2620 is a PET tracer with high binding affinity for aggregated tau, a key pathologic feature of Alzheimer disease (AD) and other neurodegenerative disorders. Preclinically, 18F-PI-2620 binds to both 3-repeat and 4-repeat tau isoforms. The purpose of this first-in-humans study was to evaluate the ability of 18F-PI-2620 to detect tau pathology in AD patients using PET imaging, as well as to assess the safety and tolerability of this new tau PET tracer. Methods: Participants with a clinical diagnosis of probable AD and healthy controls (HCs) underwent dynamic 18F-PI-2620 PET imaging for 180 min. 18F-PI-2620 binding was assessed visually and quantitatively using distribution volume ratios (DVR) estimated from noninvasive tracer kinetics and SUV ratio (SUVR) measured at different time points after injection, with the cerebellar cortex as the reference region. Time-activity curves and SUVR were assessed in AD and HC subjects, as well as DVR and SUVR correlations and effect size (Cohen's d) over time. Results: 18F-PI-2620 showed peak brain uptake around 5 min after injection and fast washout from nontarget regions. In AD subjects, focal asymmetric uptake was evident in temporal and parietal lobes, precuneus, and posterior cingulate cortex. DVR and SUVR in these regions were significantly higher in AD subjects than in HCs. Very low background signal was observed in HCs. 18F-PI-2620 administration was safe and well tolerated. SUVR time-activity curves in most regions and subjects achieved a secular equilibrium after 40 min after injection. A strong correlation (R 2 > 0.93) was found between noninvasive DVR and SUVR for all imaging windows starting at more than 30 min after injection. Similar effect sizes between AD and HC groups were obtained across the different imaging windows. 18F-PI-2620 uptake in neocortical regions significantly correlated with the degree of cognitive impairment. Conclusion: Initial clinical data obtained in AD and HC subjects demonstrated a high image quality and excellent signal-to-noise ratio of 18F-PI-2620 PET for imaging tau deposition in AD subjects. Noninvasive quantification using DVR and SUVR for 30-min imaging windows between 30 and 90 min after injection-for example, 45-75 min-provides robust and significant discrimination between AD and HC subjects. 18F-PI-2620 uptake in expected regions correlates strongly with neurocognitive performance.
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Evaluation of Dosimetry, Quantitative Methods, and Test-Retest Variability of 18F-PI-2620 PET for the Assessment of Tau Deposits in the Human Brain. J Nucl Med 2019; 61:920-927. [PMID: 31712324 DOI: 10.2967/jnumed.119.236240] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 11/04/2019] [Indexed: 02/01/2023] Open
Abstract
18F-PI-2620 is a next-generation tau PET tracer that has demonstrated ability to image the spatial distribution of suspected tau pathology. The objective of this study was to assess the tracer biodistribution, dosimetry, and quantitative methods of 18F-PI-2620 in the human brain. Full kinetic modeling to quantify tau load was investigated. Noninvasive kinetic modeling and semiquantitative methods were evaluated against the full tracer kinetics. Finally, the reproducibility of PET measurements from test and retest scans was assessed. Methods: Three healthy controls (HCs) and 4 Alzheimer disease (AD) subjects underwent 2 dynamic PET scans, including arterial sampling. Distribution volume ratio (DVR) was estimated using full tracer kinetics (reversible 2-tissue-compartment [2TC] model and Logan graphical analysis [LGA]) and noninvasive kinetic models (noninvasive LGA [NI-LGA] and the multilinear reference tissue model [MRTM2]). SUV ratio (SUVR) was determined at different imaging windows after injection. The correlation between DVR and SUVR, effect size (Cohen's d), and test-retest variability (TRV) were evaluated. Additionally, 6 HCs received 1 tracer administration and underwent whole-body PET for dosimetry calculation. Organ doses and the whole-body effective dose were calculated using OLINDA 2.0. Results: A strong correlation was found across different kinetic models (R 2 > 0.97) and between DVR(2TC) and SUVR between 30 and 90 min, with an R 2 of more than 0.95. Secular equilibrium was reached at around 40 min after injection in most regions and subjects. TRV and effect size for SUVR across different regions were similar at 30-60 min (TRV, 3.8%; Cohen's d, 3.80), 45-75 min (TRV, 4.3%; Cohen's d, 3.77) and 60-90 min (TRV, 4.9%; Cohen's d, 3.73) and increased at later time points. Elimination was via the hepatobiliary and urinary systems. The whole-body effective dose was 33.3 ± 2.1 μSv/MBq for an adult female and 33.1 ± 1.4 μSv/MBq for an adult male, with a 1.5-h urinary bladder voiding interval. Conclusion: 18F-PI-2620 exhibits fast kinetics, suitable dosimetry, and low TRV. DVR measured using the 2TC model with arterial sampling correlated strongly with DVR measured by NI-LGA, MRTM2, and SUVR. SUVR can be used for 18F-PI-2620 PET quantification of tau deposits, avoiding arterial blood sampling. Static 18F-PI-2620 PET scans between 45 and 75 min after injection provide excellent quantification accuracy, a large effect size, and low TRV.
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Cross-sectional and longitudinal characterization of SCD patients recruited from the community versus from a memory clinic: subjective cognitive decline, psychoaffective factors, cognitive performances, and atrophy progression over time. ALZHEIMERS RESEARCH & THERAPY 2019; 11:61. [PMID: 31286994 PMCID: PMC6615169 DOI: 10.1186/s13195-019-0514-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 06/13/2019] [Indexed: 12/04/2022]
Abstract
Background Subjective cognitive decline (SCD) defines a heterogeneous population, part of which having Alzheimer’s disease (AD). We aimed at characterizing SCD populations according to whether or not they referred to a memory clinic, by assessing the factors associated with increased AD risk. Methods Seventy-eight cognitively unimpaired older adults from the IMAP+ study (Caen) were included, amongst which 28 healthy controls (HC) and 50 SCD recruited from the community (SCD-community; n = 23) or from a memory clinic (SCD-clinic; n = 27). Participants underwent cognitive, psychoaffective, structural MRI, FDG-PET, and amyloid-PET assessments. They were followed up over a mean period of 2.4 ± 0.8 years. The groups were compared in terms of baseline and follow-up levels of SCD (self- and informant-reported), cognition, subclinical anxiety and depression, and atrophy progression over time. We also investigated SCD substrates within each SCD group through the correlations between self-reported SCD and other psychometric and brain measures. Results Compared to HC, both SCD groups showed similar cognitive performances but higher informant-reported SCD and anxiety. Compared to SCD-community, SCD-clinic showed higher informant-reported SCD, depression score, and atrophy progression over time but similar brain amyloid load. A significant increase over time was found for depression in the SCD-community and for self-reported praxis-domestic activities SCD factor in the SCD-clinic. Higher self-reported SCD correlated with (i) lower grey matter volume and higher anxiety in SCD-community, (ii) greater informant-reported SCD in SCD-clinic, and (iii) lower glucose metabolism in both SCD groups. Conclusions Higher subclinical depression and informant-reported SCD specifically characterize the SCD group that refers to a memory clinic. The same group appears as a frailer population than SCD-community as they show greater atrophy progression over time. Yet, both the SCD groups were quite similar otherwise including for brain amyloid load and the SCD-community showed increased depression score over time. Altogether, our findings highlight the relevance of assessing psychoaffective factors and informant-reported SCD in SCD populations and point to both differences and similarities in SCD populations referring or not to a memory clinic. Electronic supplementary material The online version of this article (10.1186/s13195-019-0514-z) contains supplementary material, which is available to authorized users.
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IC-P-125: IMPACT OF THE RECRUITMENT SETTING ON THE CHARACTERISTICS OF PATIENTS WITH SUBJECTIVE COGNITIVE DECLINE. Alzheimers Dement 2019. [DOI: 10.1016/j.jalz.2019.06.4239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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P4-295: ASSOCIATION OF PERCEIVED MEMORY DECLINE WITH MULTIMODAL NEUROIMAGING AT DIFFERENT STAGES OF ALZHEIMER'S DISEASE. Alzheimers Dement 2019. [DOI: 10.1016/j.jalz.2019.06.3964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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IC-P-082: ASSOCIATION OF PERCEIVED MEMORY DECLINE WITH MULTIMODAL NEUROIMAGING AT DIFFERENT STAGES OF ALZHEIMER'S DISEASE. Alzheimers Dement 2019. [DOI: 10.1016/j.jalz.2019.06.4925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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The elusive tau molecular structures: can we translate the recent breakthroughs into new targets for intervention? Acta Neuropathol Commun 2019; 7:31. [PMID: 30823892 PMCID: PMC6397507 DOI: 10.1186/s40478-019-0682-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 02/20/2019] [Indexed: 12/11/2022] Open
Abstract
Insights into tau molecular structures have advanced significantly in recent years. This field has been the subject of recent breakthroughs, including the first cryo-electron microscopy structures of tau filaments from Alzheimer’s and Pick’s disease inclusions, as well as the structure of the repeat regions of tau bound to microtubules. Tau structure covers various species as the tau protein itself takes many forms. We will here address a range of studies that help to define the many facets of tau protein structures and how they translate into pathogenic forms. New results shed light on previous data that need now to be revisited in order to up-date our knowledge of tau molecular structure. Finally, we explore how these data can contribute the important medical aspects of this research - diagnosis and therapeutics.
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Regional patterns of gray matter volume, hypometabolism, and beta-amyloid in groups at risk of Alzheimer's disease. Neurobiol Aging 2017; 63:140-151. [PMID: 29203090 DOI: 10.1016/j.neurobiolaging.2017.10.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/26/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is characterized by the presence of β-amyloid (Aβ) deposition and neurodegeneration. To seek for signs of such pathologies, we compared regional biomarker degrees and patterns of Aβ deposition, glucose hypometabolism, and gray matter volume (GMV) reduction in 3 groups at risk of AD. In elderly carriers of the apolipoprotein E ε4 (APOE4, n = 17), patients with subjective cognitive decline (n = 16), and patients with mild cognitive impairment (n = 30), head-to-head intermodality comparisons were performed on cross-sectional structural magnetic resonance images as well as 18F-fluorodeoxyglucose and 18F-florbetapir positron emission tomography scans. In mild cognitive impairment patients, 3 distinct biomarker patterns were recovered, similarly seen in AD patients: (1) in medial temporal regions, local GMV reduction exceeded hypometabolism, (2) in temporoparietal regions, hypometabolism predominated over GMV reduction, and (3) in frontal regions, Aβ deposition exceeded GMV reduction and hypometabolism. In subjective cognitive decline patients, only pattern 1 was detected, while APOE4 carriers demonstrated only pattern 3. Our findings highlight that regional AD-like biomarker patterns may vary across different at-risk populations, potentially reflecting differential mediators of these risks.
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Added value of
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F‐florbetaben amyloid PET in the diagnostic workup of most complex patients with dementia in France: A naturalistic study. Alzheimers Dement 2017; 14:293-305. [DOI: 10.1016/j.jalz.2017.09.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/29/2017] [Accepted: 09/06/2017] [Indexed: 11/25/2022]
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[P1–347]: ASSOCIATION OF SELF‐PERCEIVED PHYSICAL HEALTH WITH AMYLOID DEPOSITION IN COGNITIVELY NORMAL ADULTS AND SCD PATIENTS. Alzheimers Dement 2017. [DOI: 10.1016/j.jalz.2017.06.363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Distinct white matter injury associated with medial temporal lobe atrophy in Alzheimer's versus semantic dementia. Hum Brain Mapp 2017; 38:1791-1800. [PMID: 27981671 PMCID: PMC6866822 DOI: 10.1002/hbm.23482] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 11/15/2016] [Accepted: 11/21/2016] [Indexed: 01/31/2023] Open
Abstract
This study aims at further understanding the distinct vulnerability of brain networks in Alzheimer's disease (AD) versus semantic dementia (SD) investigating the white matter injury associated with medial temporal lobe (MTL) atrophy in both conditions. Twenty-six AD patients, twenty-one SD patients, and thirty-nine controls underwent a high-resolution T1-MRI scan allowing to obtain maps of grey matter volume and white matter density. A statistical conjunction approach was used to identify MTL regions showing grey matter atrophy in both patient groups. The relationship between this common grey matter atrophy and white matter density maps was then assessed within each patient group. Patterns of grey matter atrophy were distinct in AD and SD but included a common region in the MTL, encompassing the hippocampus and amygdala. This common atrophy was associated with alterations in different white matter areas in AD versus SD, mainly including the cingulum and corpus callosum in AD, while restricted to the temporal lobe - essentially the uncinate and inferior longitudinal fasciculi - in SD. Complementary analyses revealed that these relationships remained significant when controlling for global atrophy or disease severity. Overall, this study provides the first evidence that atrophy of the same MTL region is related to damage in distinct white matter fibers in AD and SD. These different patterns emphasize the vulnerability of distinct brain networks related to the MTL in these two disorders, which might underlie the discrepancy in their symptoms. These results further suggest differences between AD and SD in the neuropathological processes occurring in the MTL. Hum Brain Mapp 38:1791-1800, 2017. © 2017 Wiley Periodicals, Inc.
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Neural Correlates of Self-Reference Effect in Early Alzheimer’s Disease. J Alzheimers Dis 2017; 56:717-731. [DOI: 10.3233/jad-160561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Subjective cognitive decline in cognitively normal elders from the community or from a memory clinic: Differential affective and imaging correlates. Alzheimers Dement 2016; 13:550-560. [PMID: 27693187 DOI: 10.1016/j.jalz.2016.08.011] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/05/2016] [Accepted: 08/17/2016] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Subjective cognitive decline (SCD) could indicate preclinical Alzheimer's disease, but the existing literature is confounded by heterogeneous approaches to studying SCD. We assessed the differential cognitive, affective, and neuroimaging correlates of two aspects of SCD: reporting high cognitive difficulties on a self-rated questionnaire versus consulting at a memory clinic. METHODS We compared 28 patients from a memory clinic with isolated SCD, 35 community-recruited elders with similarly high levels of self-reported cognitive difficulties, and 35 community-recruited controls with low self-reported cognitive difficulties. RESULTS Increased anxiety and amyloid β deposition were observed in both groups with high self-reported difficulties, whereas subclinical depression and (hippocampal) atrophy were specifically associated with medical help seeking. Cognitive tests showed no group differences. DISCUSSION These results further validate the concept of SCD in both community- and clinic-based groups. Yet, recruitment methods influence associated biomarkers and affective symptomatology, highlighting the heterogeneous nature of SCD depending on study characteristics.
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Relative effect of
APOE
ε4 on neuroimaging biomarker changes across the lifespan. Neurology 2016; 87:1696-1703. [DOI: 10.1212/wnl.0000000000003234] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 07/05/2016] [Indexed: 11/15/2022] Open
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Hippocampal Subfield Volumetry and 3D Surface Mapping in Subjective Cognitive Decline. J Alzheimers Dis 2016; 48 Suppl 1:S141-50. [PMID: 26402076 DOI: 10.3233/jad-150087] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Subjective cognitive decline (SCD) may be the first clinical sign of Alzheimer's disease (AD). SCD individuals with normal cognition may already have significant hippocampal atrophy, a well-known feature of AD. OBJECTIVE To test the hypothesis that SCD, compared to healthy individuals without SCD, have a pattern of hippocampal subfield atrophy similar to that measured in the AD pathology. METHODS 17 SCD, 21 AD, and 40 matched controls underwent a standard T1-weighted MRI and a dedicated high-resolution MRI proton-density hippocampal sequence. For each participant, three hippocampal regions-of-interest were manually delineated on the proton-density hippocampal sequence corresponding to the CA1, subiculum, and other (including CA2-3-4 and dentate gyrus) subfields. Total intracranial volume (TIV)-normalized subfield volumes were compared between-group. Voxelwise group comparisons assessed from the standard T1 MRI were also projected on 3D hippocampal surface views. RESULTS Both patient groups showed significant TIV-normalized volume decrease in hippocampus global volume and in CA1 and subiculum subfields as well as in the other subfield in AD compared to controls. Significant differences were observed between SCD and AD in hippocampus global TIV-normalized volume. Atrophy maps on hippocampal surface showed major involvement of the lateral part (CA1) in both SCD and AD, with larger overlap of other regions in AD. CONCLUSION The findings indicate topographically similar hippocampal subfield changes in SCD individuals as those found in AD. This further highlights the relevance of SCD recruited from a memory clinic in assessing pre-dementia AD stages.
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P2‐343: Quali‐Quantitative Assessment of Self‐Reported Cognitive Difficulties in Non‐Demented Elders: Relationships with Medical Help Seeking, Cognition and Neuroimaging Biomarkers. Alzheimers Dement 2016. [DOI: 10.1016/j.jalz.2016.06.1473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Atrophy, hypometabolism and clinical trajectories in patients with amyloid-negative Alzheimer's disease. Brain 2016; 139:2528-39. [PMID: 27357349 DOI: 10.1093/brain/aww159] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 05/16/2016] [Indexed: 11/14/2022] Open
Abstract
See O'Sullivan and Vann (doi:10.1093/aww166) for a scientific commentary on this article.About 15% of patients clinically diagnosed with Alzheimer's disease do not show high tracer retention on amyloid positon emission tomography imaging. The present study investigates clinical and demographic features, patterns of brain atrophy and hypometabolism and longitudinal clinical trajectories of these patients. Forty amyloid-negative patients carrying a pre-scan diagnosis of Alzheimer's disease dementia from four centres were included (11/29 females/males; mean age = 67 ± 9). Detailed clinical histories, including the clinical diagnoses before and after the amyloid scan and at follow-up, were collected. Patients were classified according to their pre-scan clinical phenotype as amnestic (memory predominant), non-amnestic (predominant language, visuospatial or frontal symptoms), or non-specific (diffuse cognitive deficits). Demographic, clinical, neuropsychological, magnetic resonance imaging and (18)F-fluorodeoxyglucose positon emission tomography data were compared to 27 amyloid-positive typical Alzheimer's disease cases (14/13 females/males; mean age = 71 ± 10) and 29 amyloid-negative controls (15/14 females/males; mean age = 69 ± 12) matched for age, gender and education. There were 21 amnestic, 12 non-amnestic, and seven non-specific amyloid-negative Alzheimer's disease cases. Amyloid-negative subgroups did not differ in age, gender or education. After the amyloid scan, clinicians altered the diagnosis in 68% of amyloid-negative patients including 48% of amnestic versus 94% of non-amnestic and non-specific cases. Amnestic amyloid-negative cases were most often reclassified as frontotemporal dementia, non-amnestic as frontotemporal dementia or corticobasal degeneration, and non-specific as dementia with Lewy bodies or unknown diagnosis. The longer-term clinical follow-up was consistent with the post-scan diagnosis in most cases (90%), including in amnestic amyloid-negative cases whose post-positon emission tomography diagnosis remained Alzheimer's disease. While the non-amnestic and non-specific amyloid-negative cases usually showed patterns of atrophy and hypometabolism suggestive of another degenerative disorder, the amnestic amyloid-negative cases had subtle atrophy and hypometabolism, restricted to the retrosplenial/posterior cingulate cortex. Patients with a negative amyloid positon emission tomography scan following an initial clinical diagnosis of Alzheimer's disease have heterogeneous clinical presentations and neuroimaging profiles; a majority showed a clinical progression that was consistent with a neurodegenerative condition. In contrast, in the subgroup of amnestic amyloid-negative cases, the clinical presentation and follow-up usually remained consistent with Alzheimer's disease. An alternative diagnosis was not made in about half of the amnestic amyloid-negative cases, highlighting the need for a clinical framework and terminology to define these patients, who may have underlying limbic-predominant, non-amyloid-related pathologies.
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Episodic feeling-of-knowing relies on noncriterial recollection and familiarity: Evidence using an online remember-know procedure. Conscious Cogn 2016; 41:31-40. [DOI: 10.1016/j.concog.2016.01.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 01/14/2016] [Accepted: 01/25/2016] [Indexed: 11/26/2022]
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Interaction between years of education and APOE ε4 status on frontal and temporal metabolism. Neurology 2015; 85:1392-9. [PMID: 26408498 PMCID: PMC4626241 DOI: 10.1212/wnl.0000000000002034] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 06/23/2015] [Indexed: 11/15/2022] Open
Abstract
Objective: To examine interactions between years of education and APOE ε4 status on gray matter volume and metabolism in cognitively healthy participants. Methods: Seventy-two healthy participants (28 APOE ε4 carriers and 44 noncarriers; from 23 to 84 years of age) with FDG-PET and structural MRI were included. A subgroup also underwent florbetapir-PET. We tested the interaction effect between years of education and APOE ε4 status (carrier vs noncarrier) on FDG-PET and structural MRI within the whole brain (voxel-wise) adjusting for age and sex. Computed florbetapir standardized uptake value ratios were used for complementary analyses. Results: We found an interaction between years of education and APOE ε4 status on frontotemporal FDG-PET metabolism, such that higher education was positively related to frontotemporal metabolism only in APOE ε4 carriers. Complementary analyses revealed that (1) this interaction was independent from amyloid load; (2) increased metabolism in APOE ε4 carriers in this region correlated with episodic memory performances; (3) lower educated APOE ε4 carriers showed decreased metabolism relative to noncarriers in medial temporal and prefrontal areas, while higher educated carriers were comparable to noncarriers in these areas and showed increased metabolism in the middle temporal lobe. Conclusions: Our results showed that education may counteract the effects of APOE ε4 on metabolism independently of amyloid deposition. Higher metabolism in higher (compared to lower) educated APOE ε4 carriers was found in regions that sustain episodic memory. Overall, our results point to education as a protective factor that may help to postpone cognitive changes in APOE ε4 carriers.
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Subjective Cognitive Decline in Older Adults: An Overview of Self-Report Measures Used Across 19 International Research Studies. J Alzheimers Dis 2015; 48 Suppl 1:S63-86. [PMID: 26402085 PMCID: PMC4617342 DOI: 10.3233/jad-150154] [Citation(s) in RCA: 292] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Research increasingly suggests that subjective cognitive decline (SCD) in older adults, in the absence of objective cognitive dysfunction or depression, may be a harbinger of non-normative cognitive decline and eventual progression to dementia. Little is known, however, about the key features of self-report measures currently used to assess SCD. The Subjective Cognitive Decline Initiative (SCD-I) Working Group is an international consortium established to develop a conceptual framework and research criteria for SCD (Jessen et al., 2014, Alzheimers Dement 10, 844-852). In the current study we systematically compared cognitive self-report items used by 19 SCD-I Working Group studies, representing 8 countries and 5 languages. We identified 34 self-report measures comprising 640 cognitive self-report items. There was little overlap among measures- approximately 75% of measures were used by only one study. Wide variation existed in response options and item content. Items pertaining to the memory domain predominated, accounting for about 60% of items surveyed, followed by executive function and attention, with 16% and 11% of the items, respectively. Items relating to memory for the names of people and the placement of common objects were represented on the greatest percentage of measures (56% each). Working group members reported that instrument selection decisions were often based on practical considerations beyond the study of SCD specifically, such as availability and brevity of measures. Results document the heterogeneity of approaches across studies to the emerging construct of SCD. We offer preliminary recommendations for instrument selection and future research directions including identifying items and measure formats associated with important clinical outcomes.
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Anosognosia in Alzheimer disease: Disconnection between memory and self-related brain networks. Ann Neurol 2015; 78:477-86. [PMID: 26085009 DOI: 10.1002/ana.24462] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 05/20/2015] [Accepted: 06/14/2015] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Impaired awareness is a common symptom in many mental disorders including Alzheimer disease (AD). This study aims at improving our understanding of the neural mechanisms underlying anosognosia of memory deficits in AD by combining measures of regional brain metabolism (resting state fluorodeoxyglucose positron emission tomography [FDG-PET]) and intrinsic connectivity (resting state functional magnetic resonance imaging [fMRI]). METHODS Twenty-three patients diagnosed with probable AD based on clinical and biomarker data and 30 matched healthy control subjects were recruited in this study. An anosognosia index (difference between subjective and objective memory scores) was obtained in each participant. Resting state FDG-PET for glucose metabolism measurement and resting state fMRI for intrinsic connectivity measurement were also performed. AD and control groups were compared on behavioral data, and voxelwise correlations between anosognosia and neuroimaging data were conducted within the AD group. RESULTS AD patients underestimated their memory deficits. Anosognosia in AD patients correlated with hypometabolism in orbitofrontal (OFC) and posterior cingulate (PCC) cortices. Using OFC and PCC as seed regions, intrinsic connectivity analyses in AD revealed a significant association between anosognosia and reduced intrinsic connectivity between these regions as well as with the medial temporal lobe. INTERPRETATION Anosognosia in AD is due not only to functional changes within cortical midline structures involved in self-referential processes (OFC, PCC), but also to disconnection between these regions as well as with the medial temporal lobe. These findings suggest that the lack of awareness of memory deficits in AD results from a disruption of the communication within, but also between, the self-related and the memory-related brain networks.
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O5‐02‐05: Subjective cognitive decline: A differential vulnerability of the hippocampal subfields? Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.07.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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P2‐136: Different pathways to Alzheimer's disease? atrophy, hypometabolism, and beta‐amyloid deposition in diagnostic groups at increased risk. Alzheimers Dement 2015. [DOI: 10.1016/j.jalz.2015.06.674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Brain structural, functional, and cognitive correlates of recent versus remote autobiographical memories in amnestic Mild Cognitive Impairment. NEUROIMAGE-CLINICAL 2015; 8:473-82. [PMID: 26106572 PMCID: PMC4474362 DOI: 10.1016/j.nicl.2015.05.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/29/2015] [Accepted: 05/22/2015] [Indexed: 11/13/2022]
Abstract
Deficits in autobiographical memory appear earlier for recent than for remote life periods over the course of Alzheimer's disease (AD). The present study aims to further our understanding of this graded effect by investigating the cognitive and neural substrates of recent versus remote autobiographical memories in patients with amnestic Mild Cognitive Impairment (aMCI) thanks to an autobiographical fluency task. 20 aMCI patients and 25 Healthy elderly Controls (HC) underwent neuropsychological tests assessing remote (20-to-30 years old) and recent (the ten last years) autobiographical memory as well as episodic and semantic memory, executive function and global cognition. All patients also had a structural MRI and an FDG-PET scan. Correlations were assessed between each autobiographical memory score and the other tests as well as grey matter volume and metabolism. Within the aMCI, performances for the remote period correlated with personal semantic memory and episodic memory retrieval whereas performances for the recent period only correlated with episodic memory retrieval. Neuroimaging analyses revealed significant correlations between performances for the remote period and temporal pole and temporo-parietal cortex volumes and anterior cingulate gyrus metabolism, while performances for the recent period correlated with hippocampal volume and posterior cingulate, medial prefrontal and hippocampus metabolism. The brain regions related with the retrieval of events from the recent period showed greater atrophy/hypometabolism in aMCI patients compared to HC than those involved in remote memories. Recall of recent memories essentially relies on episodic memory processes and brain network while remote memories also involve other processes such as semantic memory. This is consistent with the semanticization of memories with time and may explain the better resistance of remote memory in AD. We studied cognitive correlates of recent and remote autobiographical memories in aMCI. We evaluated brain structural and functional correlates of each period of life. Recent memories rely on episodic memory processes and brain network. Remote memories also involve other processes such as semantic memory. These findings contribute to explain the better resistance of remote memory in aMCI.
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Une nouvelle épreuve de mémoire épisodique : l’épreuve ESR-forme réduite (ESR-r), adaptée du paradigme ESR (encodage, stockage, récupération). ACTA ACUST UNITED AC 2015. [DOI: 10.3917/rne.073.0217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Effects of age and Alzheimer's disease on hippocampal subfields: comparison between manual and FreeSurfer volumetry. Hum Brain Mapp 2014; 36:463-74. [PMID: 25231681 DOI: 10.1002/hbm.22640] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/26/2014] [Accepted: 09/09/2014] [Indexed: 11/08/2022] Open
Abstract
Growing interest has developed in hippocampal subfield volumetry over the past few years and an increasing number of studies use the automatic segmentation algorithm implemented in FreeSurfer. However, this approach has not been validated on standard resolution T1-weighted magnetic resonance (MR) as used in most studies. We aimed at comparing hippocampal subfield segmentation using FreeSurfer on standard T1-weighted images versus manual delineation on dedicated high-resolution hippocampal scans. Hippocampal subfields were segmented in 133 individuals including 98 cognitively normal controls aged 19-84 years, 17 mild cognitive impairment and 18 Alzheimer's disease (AD) patients using both methods. Intraclass correlation coefficients (ICC) and Bland-Altman plots were computed to assess the consistency between both methods, and the effects of age and diagnosis were assessed from both measures. Low to moderate ICC (0.31-0.74) were found for the subiculum and other subfields as well as for the whole hippocampus, and the correlations were very low for cornu ammonis (CA)1 (<0.1). FreeSurfer CA1 volume estimates were found to be much lower than those obtained from manual segmentation, and this bias was proportional to the volume of this structure so that no effect of age or AD could be detected on FreeSurfer CA1 volumes. This study points to the differences in the anatomic definition of the subfields between FreeSurfer and manual delineation, especially for CA1, and provides clue for improvement of this automatic technique for potential clinical application on standard T1-weighted MR.
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P4‐081: WHAT IS WORSE IN HEALTHY ELDERLY INDIVIDUALS: HAVING AMYLOID DEPOSITION IN THE BRAIN OR REFERRING TO A MEMORY CLINIC WITH SUBJECTIVE COGNITIVE DECLINE? Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.1596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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IC‐P‐156: BRAIN STRUCTURAL, FUNCTIONAL, AND COGNITIVE CORRELATES OF RECENT VERSUS REMOTE AUTOBIOGRAPHICAL MEMORIES IN MILD COGNITIVE IMPAIRMENT. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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IC‐P‐009: NEURODEGENERATIVE AND COGNITIVE PROFILE OF PATIENTS WITH A TYPICAL PHENOTYPE OF AD BUT WITH A NEGATIVE AMYLOID SCAN. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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P1‐299: BRAIN STRUCTURAL, FUNCTIONAL, AND COGNITIVE CORRELATES OF RECENT VERSUS REMOTE AUTOBIOGRAPHICAL MEMORIES IN MILD COGNITIVE IMPAIRMENT. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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O4‐01‐06: NEURODEGENERATIVE AND COGNITIVE PROFILE OF PATIENTS WITH A TYPICAL PHENOTYPE OF AD BUT WITH A NEGATIVE AMYLOID SCAN. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.04.389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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IC‐P‐171: INTERACTION BETWEEN YEARS OF EDUCATION AND APOE E4 STATUS IN COGNITIVELY NORMAL SUBJECTS: A MULTIMODAL NEUROIMAGING STUDY. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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IC‐P‐104: WHAT IS WORSE IN HEALTHY ELDERLY INDIVIDUALS: HAVING AMYLOID DEPOSITION IN THE BRAIN OR REFERRING TO A MEMORY CLINIC WITH SUBJECTIVE COGNITIVE DECLINE? Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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IC‐P‐105: IS HIPPOCAMPAL ATROPHY IN HEALTHY ELDERLY INDIVIDUALS WITH SUBJECTIVE COGNITIVE DECLINE RELATED TO AMYLOID DEPOSITION? Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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P2‐209: DIFFERENTIAL EFFECT OF AGE ON ALZHEIMER'S DISEASE BIOMARKERS IN COGNITIVELY NORMAL APOLIPOPROTEIN E4 CARRIERS AND NON‐CARRIERS. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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IC‐P‐093: EFFECTS OF AGE AND ALZHEIMER'S DISEASE ON HIPPOCAMPAL SUBFIELDS: COMPARISON BETWEEN MANUAL AND FREESURFER VOLUMETRY. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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IC‐P‐010: CLINICALLY DIAGNOSED PROBABLE AD CASES WITH A NEGATIVE AMYLOID PET SCAN: CLINICAL FINDINGS. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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O1‐07‐01: INTERACTION BETWEEN YEARS OF EDUCATION AND APOE E4 STATUS IN COGNITIVELY NORMAL SUBJECTS: A MULTIMODAL NEUROIMAGING STUDY. Alzheimers Dement 2014. [DOI: 10.1016/j.jalz.2014.04.092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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49
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Intrinsic connectivity identifies the hippocampus as a main crossroad between Alzheimer's and semantic dementia-targeted networks. Neuron 2014; 81:1417-1428. [PMID: 24656258 DOI: 10.1016/j.neuron.2014.01.026] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/07/2014] [Indexed: 11/17/2022]
Abstract
Alzheimer's disease (AD) and semantic dementia (SD) are both characterized by severe atrophy in the hippocampus, a brain region underlying episodic memory; paradoxically, episodic memory is relatively preserved in SD. Here, we used intrinsic connectivity analyses and showed that the brain networks differentially vulnerable to each disease converge to the hippocampus in the healthy brain. As neurodegeneration is thought to spread within preexisting networks, the common hippocampal atrophy in both diseases is likely due to its location at the crossroad between both vulnerable networks. Yet, we showed that in the normal brain, these networks harbor different functions, with episodic memory relying on the AD-vulnerable network only. Overall, disease-associated cognitive deficits seem to reflect the disruption of targeted networks more than atrophy in specific brain regions: in AD, over hippocampal atrophy, episodic memory deficits are likely due to disconnection within a memory-related network.
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A conceptual framework for research on subjective cognitive decline in preclinical Alzheimer's disease. Alzheimers Dement 2014; 10:844-52. [PMID: 24798886 DOI: 10.1016/j.jalz.2014.01.001] [Citation(s) in RCA: 1688] [Impact Index Per Article: 168.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/23/2013] [Accepted: 01/09/2014] [Indexed: 11/26/2022]
Abstract
There is increasing evidence that subjective cognitive decline (SCD) in individuals with unimpaired performance on cognitive tests may represent the first symptomatic manifestation of Alzheimer's disease (AD). The research on SCD in early AD, however, is limited by the absence of common standards. The working group of the Subjective Cognitive Decline Initiative (SCD-I) addressed this deficiency by reaching consensus on terminology and on a conceptual framework for research on SCD in AD. In this publication, research criteria for SCD in pre-mild cognitive impairment (MCI) are presented. In addition, a list of core features proposed for reporting in SCD studies is provided, which will enable comparability of research across different settings. Finally, a set of features is presented, which in accordance with current knowledge, increases the likelihood of the presence of preclinical AD in individuals with SCD. This list is referred to as SCD plus.
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