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1.
Alzheimers Res Ther ; 16(1): 119, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38822365

RESUMO

BACKGROUND: Autopsy work reported that neuronal density in the locus coeruleus (LC) provides neural reserve against cognitive decline in dementia. Recent neuroimaging and pharmacological studies reported that left frontoparietal network functional connectivity (LFPN-FC) confers resilience against beta-amyloid (Aß)-related cognitive decline in preclinical sporadic and autosomal dominant Alzheimer's disease (AD), as well as against LC-related cognitive changes. Given that the LFPN and the LC play important roles in attention, and attention deficits have been observed early in the disease process, we examined whether LFPN-FC and LC structural health attenuate attentional decline in the context of AD pathology. METHODS: 142 participants from the Harvard Aging Brain Study who underwent resting-state functional MRI, LC structural imaging, PiB(Aß)-PET, and up to 5 years of cognitive follow-ups were included (mean age = 74.5 ± 9.9 years, 89 women). Cross-sectional robust linear regression associated LC integrity (measured as the average of five continuous voxels with the highest intensities in the structural LC images) or LFPN-FC with Digit Symbol Substitution Test (DSST) performance at baseline. Longitudinal robust mixed effect analyses examined associations between DSST decline and (i) two-way interactions of baseline LC integrity (or LFPN-FC) and PiB or (ii) the three-way interaction of baseline LC integrity, LFPN-FC, and PiB. Baseline age, sex, and years of education were included as covariates. RESULTS: At baseline, lower LFPN-FC, but not LC integrity, was related to worse DSST performance. Longitudinally, lower baseline LC integrity was associated with a faster DSST decline, especially at PiB > 10.38 CL. Lower baseline LFPN-FC was associated with a steeper decline on the DSST but independent of PiB. At elevated PiB levels (> 46 CL), higher baseline LFPN-FC was associated with an attenuated decline on the DSST, despite the presence of lower LC integrity. CONCLUSIONS: Our findings demonstrate that the LC can provide resilience against Aß-related attention decline. However, when Aß accumulates and the LC's resources may be depleted, the functioning of cortical target regions of the LC, such as the LFPN-FC, can provide additional resilience to sustain attentional performance in preclinical AD. These results provide critical insights into the neural correlates contributing to individual variability at risk versus resilience against Aß-related cognitive decline.


Assuntos
Doença de Alzheimer , Locus Cerúleo , Imageamento por Ressonância Magnética , Lobo Parietal , Humanos , Feminino , Masculino , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/psicologia , Doença de Alzheimer/fisiopatologia , Idoso , Locus Cerúleo/diagnóstico por imagem , Locus Cerúleo/patologia , Imageamento por Ressonância Magnética/métodos , Lobo Parietal/diagnóstico por imagem , Idoso de 80 Anos ou mais , Atenção/fisiologia , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/fisiopatologia , Tomografia por Emissão de Pósitrons , Estudos Transversais , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/fisiopatologia , Disfunção Cognitiva/psicologia , Testes Neuropsicológicos
2.
Neurology ; 102(12): e209447, 2024 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-38810211

RESUMO

BACKGROUND AND OBJECTIVES: Self-reported cognitive decline is an early behavioral manifestation of Alzheimer disease (AD) at the preclinical stage, often believed to precede concerns reported by a study partner. Previous work shows cross-sectional associations with ß-amyloid (Aß) status and self-reported and study partner-reported cognitive decline, but less is known about their associations with tau deposition, particularly among those with preclinical AD. METHODS: This cross-sectional study included participants from the Anti-Amyloid Treatment in Asymptomatic AD/Longitudinal Evaluation of Amyloid Risk and Neurodegeneration studies (N = 444) and the Harvard Aging Brain Study and affiliated studies (N = 231), which resulted in a cognitively unimpaired (CU) sample of individuals with both nonelevated (Aß-) and elevated Aß (Aß+). All participants and study partners completed the Cognitive Function Index (CFI). Two regional tau composites were derived by averaging flortaucipir PET uptake in the medial temporal lobe (MTL) and neocortex (NEO). Global Aß PET was measured in Centiloids (CLs) with Aß+ >26 CL. We conducted multiple linear regression analyses to test associations between tau PET and CFI, covarying for amyloid, age, sex, education, and cohort. We also controlled for objective cognitive performance, measured using the Preclinical Alzheimer Cognitive Composite (PACC). RESULTS: Across 675 CU participants (age = 72.3 ± 6.6 years, female = 59%, Aß+ = 60%), greater tau was associated with greater self-CFI (MTL: ß = 0.28 [0.12, 0.44], p < 0.001, and NEO: ß = 0.26 [0.09, 0.42], p = 0.002) and study partner CFI (MTL: ß = 0.28 [0.14, 0.41], p < 0.001, and NEO: ß = 0.31 [0.17, 0.44], p < 0.001). Significant associations between both CFI measures and MTL/NEO tau PET were driven by Aß+. Continuous Aß showed an independent effect on CFI in addition to MTL and NEO tau for both self-CFI and study partner CFI. Self-CFI (ß = 0.01 [0.001, 0.02], p = 0.03), study partner CFI (ß = 0.01 [0.003, 0.02], p = 0.01), and the PACC (ß = -0.02 [-0.03, -0.01], p < 0.001) were independently associated with MTL tau, but for NEO tau, PACC (ß = -0.02 [-0.03, -0.01], p < 0.001) and study partner report (ß = 0.01 [0.004, 0.02], p = 0.002) were associated, but not self-CFI (ß = 0.01 [-0.001, 0.02], p = 0.10). DISCUSSION: Both self-report and study partner report showed associations with tau in addition to Aß. Additionally, self-report and study partner report were associated with tau above and beyond performance on a neuropsychological composite. Stratification analyses by Aß status indicate that associations between self-reported and study partner-reported cognitive concerns with regional tau are driven by those at the preclinical stage of AD, suggesting that both are useful to collect on the early AD continuum.


Assuntos
Peptídeos beta-Amiloides , Disfunção Cognitiva , Tomografia por Emissão de Pósitrons , Proteínas tau , Humanos , Feminino , Masculino , Idoso , Proteínas tau/metabolismo , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/etiologia , Estudos Transversais , Idoso de 80 Anos ou mais , Peptídeos beta-Amiloides/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/diagnóstico por imagem , Autorrelato , Estudos de Coortes , Lobo Temporal/metabolismo , Lobo Temporal/diagnóstico por imagem , Pessoa de Meia-Idade , Neocórtex/metabolismo , Neocórtex/diagnóstico por imagem
3.
Food Funct ; 15(7): 3274-3299, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38482946

RESUMO

Cardiovascular diseases (CVDs) are a group of chronic health disorders prevalent worldwide that claim millions of lives yearly. Inflammation and oxidative stress are intricately associated with myocardial tissue damage, endothelial dysfunction, and increased odds of heart failure. Thus, dietary strategies aimed at decreasing the odds of CVDs are paramount. In this regard, the consumption of anthocyanins, natural pigments found in edible flowers, fruits, and vegetables, has attracted attention due to their potential to promote cardiovascular health. The main mechanisms of action linked with their protective effects on antioxidant and anti-inflammatory activities, serum lipid profile modulation, and other cardiovascular health parameters are explained and exemplified. However, little is known about the dose-dependency nature of the effects, which anthocyanin has better efficiency, and whether anthocyanin-containing foods display better in vivo efficacy than nutraceuticals (i.e., concentrated extracts containing higher levels of anthocyanins than foods). Thus, this systematic review focused on determining the effects of anthocyanin-containing foods and nutraceuticals on biomarkers associated with CVDs using animal studies and human interventions supported by in vitro mechanistic insights. Overall, the results showed that the regular consumption of anthocyanin-containing foods and nutraceuticals improved vascular function, lipid profile, and antioxidant and anti-inflammatory effects. The daily dosage, the participants' health status, and the duration of the intervention also significantly influenced the results.


Assuntos
Antioxidantes , Doenças Cardiovasculares , Animais , Humanos , Antioxidantes/farmacologia , Antocianinas/farmacologia , Suplementos Nutricionais , Estresse Oxidativo , Inflamação , Doenças Cardiovasculares/prevenção & controle , Doenças Cardiovasculares/tratamento farmacológico , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Biomarcadores , Lipídeos/farmacologia
4.
J Cereb Blood Flow Metab ; 44(1): 131-141, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-37728659

RESUMO

Clinically normal females exhibit higher 18F-flortaucipir (FTP)-PET signal than males across the cortex. However, these sex differences may be explained by neuroimaging idiosyncrasies such as off-target extracerebral tracer retention or partial volume effects (PVEs). 343 clinically normal participants (female = 58%; mean[SD]=73.8[8.5] years) and 55 patients with mild cognitive impairment (female = 38%; mean[SD] = 76.9[7.3] years) underwent cross-sectional FTP-PET. We parcellated extracerebral FreeSurfer areas based on proximity to cortical ROIs. Sex differences in cortical tau were then estimated after accounting for local extracerebral retention. We simulated PVE by convolving group-level standardized uptake value ratio means in each ROI with 6 mm Gaussian kernels and compared the sexes across ROIs post-smoothing. Widespread sex differences in extracerebral retention were observed. Although attenuating sex differences in cortical tau-PET signal, covarying for extracerebral retention did not impact the largest sex differences in tau-PET signal. Differences in PVE were observed in both female and male directions with no clear sex-specific bias. Our findings suggest that sex differences in FTP are not solely attributed to off-target extracerebral retention or PVE, consistent with the notion that sex differences in medial temporal and neocortical tau are biologically driven. Future work should investigate sex differences in regional cerebral blood flow kinetics and longitudinal tau-PET.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Humanos , Masculino , Feminino , Proteínas tau/metabolismo , Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Caracteres Sexuais , Estudos Transversais , Tomografia por Emissão de Pósitrons/métodos , Carbolinas/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/metabolismo , Doença de Alzheimer/metabolismo
5.
Neurology ; 101(24): e2533-e2544, 2023 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-37968130

RESUMO

BACKGROUND AND OBJECTIVES: Hippocampal volume (HV) atrophy is a well-known biomarker of memory impairment. However, compared with ß-amyloid (Aß) and tau imaging, it is less specific for Alzheimer disease (AD) pathology. This lack of specificity could provide indirect information about potential copathologies that cannot be observed in vivo. In this prospective cohort study, we aimed to assess the associations among Aß, tau, HV, and cognition, measured over a 10-year follow-up period with a special focus on the contributions of HV atrophy to cognition after adjusting for Aß and tau. METHODS: We enrolled 283 older adults without dementia or overt cognitive impairment in the Harvard Aging Brain Study. In this report, we only analyzed data from individuals with available longitudinal imaging and cognition data. Serial MRI (follow-up duration 1.3-7.0 years), neocortical Aß imaging on Pittsburgh Compound B PET scans (1.9-8.5 years), entorhinal and inferior temporal tau on flortaucipir PET scans (0.8-6.0 years), and the Preclinical Alzheimer Cognitive Composite (3.0-9.8 years) were prospectively collected. We evaluated the longitudinal associations between Aß, tau, volume, and cognition data and investigated sequential models to test the contribution of each biomarker to cognitive decline. RESULTS: We analyzed data from 128 clinically normal older adults, including 72 (56%) women and 56 (44%) men; median age at inclusion was 73 years (range 63-87). Thirty-four participants (27%) exhibited an initial high-Aß burden on PET imaging. Faster HV atrophy was correlated with faster cognitive decline (R2 = 0.28, p < 0.0001). When comparing all biomarkers, HV slope was associated with cognitive decline independently of Aß and tau measures, uniquely accounting for 10% of the variance. Altogether, 45% of the variance in cognitive decline was explained by combining the change measures in the different imaging biomarkers. DISCUSSION: In older adults, longitudinal hippocampal atrophy is associated with cognitive decline, independently of Aß or tau, suggesting that non-AD pathologies (e.g., TDP-43, vascular) may contribute to hippocampal-mediated cognitive decline. Serial HV measures, in addition to AD-specific biomarkers, may help evaluate the contribution of non-AD pathologies that cannot be measured otherwise in vivo.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Masculino , Humanos , Feminino , Idoso , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Proteínas tau , Estudos Prospectivos , Doença de Alzheimer/diagnóstico por imagem , Peptídeos beta-Amiloides , Disfunção Cognitiva/diagnóstico por imagem , Biomarcadores , Atrofia , Tomografia por Emissão de Pósitrons
6.
J Cereb Blood Flow Metab ; 43(4): 581-594, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36420769

RESUMO

[18F]MK-6240 meningeal/extracerebral off-target binding may impact tau quantification. We examined the kinetics and longitudinal changes of extracerebral and reference regions. [18F]MK-6240 PET was performed in 24 cognitively-normal and eight cognitively-impaired subjects, with arterial samples in 13 subjects. Follow-up scans at 6.1 ± 0.5 (n = 25) and 13.3 ± 0.9 (n = 16) months were acquired. Extracerebral and reference region (cerebellar gray matter (CerGM)-based, cerebral white matter (WM), pons) uptake were evaluated using standardized uptake values (SUV90-110), spectral analysis, and distribution volume. Longitudinal changes in SUV90-110 were examined. The impact of reference region on target region outcomes, partial volume correction (PVC) and regional erosion were evaluated. Eroded WM and pons showed lower variability, lower extracerebral contamination, and lower longitudinal changes than CerGM-based regions. CerGM-based regions resulted larger cross-sectional effect sizes for group differentiation. Extracerebral signal was high in 50% of subjects and exhibited irreversible kinetics and nonsignificant longitudinal changes over one-year but was highly variable at subject-level. PVC resulted in higher variability in reference region uptake and longitudinal changes. Our results suggest that eroded CerGM may be preferred for cross-sectional, whilst eroded WM or pons may be preferred for longitudinal [18F]MK-6240 studies. For CerGM, erosion was necessary (preferred over PVC) to address the heterogenous nature of extracerebral signal.


Assuntos
Disfunção Cognitiva , Humanos , Estudos Transversais , Cinética , Tomografia por Emissão de Pósitrons/métodos , Estudos de Casos e Controles
7.
J Pharm Pract ; : 8971900221126570, 2022 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-36193947

RESUMO

Some patients with epilepsy experience seizure clusters, which may be defined as 2 or more seizures occurring within 24 hours. Left untreated, seizure clusters increase the risk for physical injury and may progress to status epilepticus, irreversible neurologic injury, and death. Rescue therapy is based on benzodiazepine treatment. Prompt, appropriate use should be specified in patients' individualized seizure action plans. Most seizure clusters occur outside the hospital setting. The ideal rescue therapy allows for easy and quick administration by a nonmedical person, which may minimize the need for intervention by emergency medical personnel or transportation to the hospital. In the 2 decades before the approval of 2 intranasal benzodiazepines in 2019 and 2020, rectal diazepam was the only route of administration approved by the US Food and Drug Administration specifically for seizure clusters. Each of the approved intranasal formulations has a unique profile. Both offer a convenient and socially acceptable route of administration. Recognition of seizure clusters and timing of proper administration are key to successful use of rescue therapy. Pharmacists' counseling plays an important role in reinforcing when and how to appropriately administer rescue therapies and the importance of consistently using rescue treatment when indicated to promote effective management. This review includes resources for pharmacists, patients, and caregivers; reviews currently available treatments; and discusses seizure action plans that support effective treatment of seizure clusters.

8.
Neurology ; 98(15): e1512-e1524, 2022 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-35338074

RESUMO

BACKGROUND AND OBJECTIVES: Alzheimer disease (AD) clinical trials are moving earlier in the disease process according to emerging signs of ß-amyloid (Aß) and tau pathology. If early treatment is the right time for intervention, it is critical to find the right test to optimize cognitive outcome measures for clinical trials. We sought to identify cognitive measures associated with the earliest detectable signs of emerging Aß and tau pathology. METHODS: One hundred twelve clinically normal adults with longitudinal Pittsburgh compound B (PiB)-PET, 18F-flortaucipir (FTP)-PET, and cognitive data for ≥7 years were included from the Harvard Aging Brain Study (HABS). Analyses assessed those initially classified as PiB- (less than Centiloid [CL] 20) and then expanded to include PiB+ individuals up to CL40, the approximate threshold beyond which neocortical tau proliferation begins. Separate linear mixed-effects models assessed the effects of emerging global Aß (PiB slope) and tau (baseline FTP level and FTP slope) in the entorhinal and inferior temporal (IT) cortices on multiple cognitive tasks and the Preclinical Alzheimer's Cognitive Composite (PACC) over time. RESULTS: Steeper PiB slopes were associated with declining processing speed (Digit Symbol Substitution Test [DSST], Trail Making Test Part A) in those CL40). DISCUSSION: Early, Aß-mediated cognitive slowing was detected for processing speed measures, while early memory retrieval declines were associated with emerging Aß and tau pathology. Composites of these measures may help determine whether anti-Aß or anti-tau therapies administered at the first signs of pathology might preserve cognitive function. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that in clinically normal older adults, emerging PET-detected AD pathology is associated with declining processing speeds and memory retrieval.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Idoso , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Encéfalo/patologia , Cognição , Disfunção Cognitiva/patologia , Humanos , Tomografia por Emissão de Pósitrons , Proteínas tau/metabolismo
9.
Nat Commun ; 13(1): 1571, 2022 03 23.
Artigo em Inglês | MEDLINE | ID: mdl-35322012

RESUMO

Animal and human imaging research reported that the presence of cortical Alzheimer's Disease's (AD) neuropathology, beta-amyloid and neurofibrillary tau, is associated with altered neuronal activity and circuitry failure, together facilitating clinical progression. The locus coeruleus (LC), one of the initial subcortical regions harboring pretangle hyperphosphorylated tau, has widespread connections to the cortex modulating cognition. Here we investigate whether LC's in-vivo neuronal activity and functional connectivity (FC) are associated with cognitive decline in conjunction with beta-amyloid. We combined functional MRI of a novel versus repeated face-name paradigm, beta-amyloid-PET and longitudinal cognitive data of 128 cognitively unimpaired older individuals. We show that LC activity and LC-FC with amygdala and hippocampus was higher during novelty. We also demonstrated that lower novelty-related LC activity and LC-FC with hippocampus and parahippocampus were associated with steeper beta-amyloid-related cognitive decline. Our results demonstrate the potential of LC's functional properties as a gauge to identify individuals at-risk for AD-related cognitive decline.


Assuntos
Doença de Alzheimer , Disfunção Cognitiva , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/patologia , Locus Cerúleo/metabolismo , Tomografia por Emissão de Pósitrons , Proteínas tau/metabolismo
10.
Neurobiol Aging ; 105: 318-326, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34147860

RESUMO

We evaluated whether self-reports of worse cognition in older adults with normal cognitive function reflected actual memory decline, amyloid pathology, and subtle vulnerabilities in hippocampal function. We measured subjective cognitive decline (SCD) in 156 older participants from the Dallas Lifespan Brain Study. Functional hippocampal activation during encoding, measured with fMRI, and longitudinal memory change that was measured in the four years preceding the SCD measures were used to predict the magnitude of SCD. A subsample (N=105) also underwent 18F-Florbetapir PET imaging that measured amyloid burden. Results showed that increased SCD were associated with greater prior memory decline and amyloid deposition. Importantly, decreased hippocampal activation during encoding was a significant predictor of SCD, particularly in young-old adults below 69 years old, above and beyond prior memory change and amyloid deposition. These results indicate that multiple measures of neural and cognitive dysfunction are simultaneously associated with SCD. Moreover, SCD in younger seniors appears to reflect deficient hippocampal activity that increases their reports of poorer memory, independent of amyloid. This manuscript is part of the Special Issue entitled "Cognitive Neuroscience of Healthy and Pathological Aging" edited by Drs. M. N. Rajah, S. Belleville, and R. Cabeza. This article is part of the Virtual Special Issue titled COGNITIVE NEU-ROSCIENCE OF HEALTHY AND PATHOLOGICAL AGING. The full issue can be found on ScienceDirect at https://www.sciencedirect.com/journal/neurobiology-of-aging/special-issue/105379XPWJP.


Assuntos
Envelhecimento/metabolismo , Envelhecimento/psicologia , Peptídeos beta-Amiloides/metabolismo , Encéfalo/metabolismo , Envelhecimento Cognitivo/fisiologia , Envelhecimento Cognitivo/psicologia , Disfunção Cognitiva , Envelhecimento Saudável/metabolismo , Envelhecimento Saudável/patologia , Envelhecimento Saudável/fisiologia , Hipocampo/fisiologia , Memória/fisiologia , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/fisiologia , Feminino , Envelhecimento Saudável/psicologia , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Autorrelato
11.
Neurology ; 96(4): e619-e631, 2021 01 26.
Artigo em Inglês | MEDLINE | ID: mdl-33199430

RESUMO

INTRODUCTION: As clinical trials move toward earlier intervention, we sought to redefine the ß-amyloid (Aß)-PET threshold based on the lowest point in a baseline distribution that robustly predicts future Aß accumulation and cognitive decline in 3 independent samples of clinically normal individuals. METHODS: Sequential Aß cutoffs were tested to identify the lowest cutoff associated with future change in cognition (Preclinical Alzheimer Cognitive Composite [PACC]) and Aß-PET in clinically normal participants from the Harvard Aging Brain Study (n = 342), Australian Imaging, Biomarker and Lifestyle study of aging (n = 157), and Alzheimer's Disease Neuroimaging Initiative (n = 356). RESULTS: Within samples, cutoffs derived from future Aß-PET accumulation and PACC decline converged on the same inflection point, beyond which trajectories diverged from normal. Across samples, optimal cutoffs fell within a short range (Centiloid 15-18.5). DISCUSSION: These optimized thresholds can help to inform future research and clinical trials targeting early Aß. Threshold convergence raises the possibility of contemporaneous early changes in Aß and cognition. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that among clinically normal individuals a specific Aß-PET threshold is predictive of cognitive decline.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/metabolismo , Placa Amiloide/diagnóstico por imagem , Placa Amiloide/metabolismo , Tomografia por Emissão de Pósitrons/tendências , Idoso , Idoso de 80 Anos ou mais , Disfunção Cognitiva/psicologia , Feminino , Seguimentos , Previsões , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Placa Amiloide/psicologia , Estudos Prospectivos
12.
JAMA Neurol ; 76(8): 915-924, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31157827

RESUMO

IMPORTANCE: Positron emission tomography (PET) imaging now allows in vivo visualization of both neuropathologic hallmarks of Alzheimer disease (AD): amyloid-ß (Aß) plaques and tau neurofibrillary tangles. Observing their progressive accumulation in the brains of clinically normal older adults is critically important to understand the pathophysiologic cascade leading to AD and to inform the choice of outcome measures in prevention trials. OBJECTIVE: To assess the associations among Aß, tau, and cognition, measured during different observation periods for 7 years. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted between 2010 and 2017 at the Harvard Aging Brain Study, Boston, Massachusetts. The study enrolled 279 clinically normal participants. An additional 90 individuals were approached but declined the study or did not meet the inclusion criteria. In this report, we analyzed data from 60 participants who had multiple Aß and tau PET observations available on October 31, 2017. MAIN OUTCOMES AND MEASURES: A median of 3 Pittsburgh compound B-PET (Aß, 2010-2017) and 2 flortaucipir-PET (tau, 2013-2017) images were collected. We used initial PET and slope data, assessing the rates of change in Aß and tau, to measure cognitive changes. Cognition was evaluated annually using the Preclinical Alzheimer Cognitive Composite (2010-2017). Annual consensus meetings evaluated progression to mild cognitive impairment. RESULTS: Of the 60 participants, 35 were women (58%) and 25 were men (42%); median age at inclusion was 73 years (range, 65-85 years). Seventeen participants (28%) exhibited an initial high Aß burden. An antecedent rise in Aß was associated with subsequent changes in tau (1.07 flortaucipir standardized uptake value ratios [SUVr]/PiB-SUVr; 95% CI, 0.13-3.46; P = .02). Tau changes were associated with cognitive changes (-3.28 z scores/SUVR; 95% CI, -6.67 to -0.91; P = .001), covarying baseline Aß and tau. Tau changes were greater in the participants who progressed to mild cognitive impairment (n = 6) than in those who did not (n = 11; 0.05 SUVr per year; 95% CI, 0.03-0.07; P = .001). A serial mediation model demonstrated that the association between initial Aß and final cognition, measured 7 years later, was mediated by successive changes in Aß and tau. CONCLUSIONS AND RELEVANCE: We identified sequential changes in normal older adults, from Aß to tau to cognition, after which the participants with high Aß with greater tau increase met clinical criteria for mild cognitive impairment. These findings highlight the importance of repeated tau-PET observations to track disease progression and the importance of repeated amyloid-PET observations to detect the earliest AD pathologic changes.

13.
Alzheimers Dement (Amst) ; 11: 151-160, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30809586

RESUMO

INTRODUCTION: Amyloid pathology in cognitively normal adults is associated with subjective cognitive decline, potentially reflecting awareness of Alzheimer's-related memory deficits. To clarify the mechanism underlying this relationship, we used mediational analyses to determine the role of depression, anxiety, and actual memory performance. METHODS: To assess amyloid deposition, we imaged 85 cognitively normal adults with florbetapir positron emission tomography imaging. Subjective cognitive decline was measured using a multidimensional instrument that assessed seven subjective memory domains. Mediational measures included assessments of actual memory performance (current and retrospective longitudinal change), depression, and anxiety. RESULTS: The relationship between amyloid and subjective cognitive decline was mediated by poorer memory performance and greater retrospective memory decline, not depression or anxiety. The mediational roles were significant for domains associated with memory function and memory-related anxiety. DISCUSSION: In individuals harboring amyloid, self-reported beliefs of declining memory likely indicate early self-awareness of actual worsening function rather than depression or anxiety.

14.
JAMA Neurol ; 76(5): 542-551, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715078

RESUMO

Importance: Mounting evidence suggests that sex differences exist in the pathologic trajectory of Alzheimer disease. Previous literature shows elevated levels of cerebrospinal fluid tau in women compared with men as a function of apolipoprotein E (APOE) ε4 status and ß-amyloid (Aß). What remains unclear is the association of sex with regional tau deposition in clinically normal individuals. Objective: To examine sex differences in the cross-sectional association between Aß and regional tau deposition as measured with positron emission tomography (PET). Design, Setting and Participants: This is a study of 2 cross-sectional, convenience-sampled cohorts of clinically normal individuals who received tau and Aß PET scans. Data were collected between January 2016 and February 2018 from 193 clinically normal individuals from the Harvard Aging Brain Study (age range, 55-92 years; 118 women [61%]) who underwent carbon 11-labeled Pittsburgh Compound B and flortaucipir F18 PET and 103 clinically normal individuals from the Alzheimer's Disease Neuroimaging Initiative (age range, 63-94 years; 55 women [51%]) who underwent florbetapir and flortaucipir F 18 PET. Main Outcomes and Measures: A main association of sex with regional tau in the entorhinal cortices, inferior temporal lobe, and a meta-region of interest, which was a composite of regions in the temporal lobe. Associations between sex and global Aß as well as sex and APOE ε4 on these regions after controlling for age were also examined. Results: The mean (SD) age of all individuals was 74.2 (7.6) years (81 APOE ε4 carriers [31%]; 89 individuals [30%] with high Aß). There was no clear association of sex with regional tau that was replicated across studies. However, in both cohorts, clinically normal women exhibited higher entorhinal cortical tau than men (meta-analytic estimate: ß [male] = -0.11 [0.05]; 95% CI, -0.21 to -0.02; P = .02), which was associated with individuals with higher Aß burden. A sex by APOE ε4 interaction was not associated with regional tau (meta-analytic estimate: ß [male, APOE ε4+] = -0.15 [0.09]; 95% CI, -0.32 to 0.01; P = .07). Conclusions and Relevance: Early tau deposition was elevated in women compared with men in individuals on the Alzheimer disease trajectory. These findings lend support to a growing body of literature that highlights a biological underpinning for sex differences in Alzheimer disease risk.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Encéfalo/diagnóstico por imagem , Proteínas tau/metabolismo , Idoso , Idoso de 80 Anos ou mais , Compostos de Anilina , Apolipoproteína E4/genética , Encéfalo/metabolismo , Carbolinas , Meios de Contraste , Estudos Transversais , Córtex Entorrinal/diagnóstico por imagem , Córtex Entorrinal/metabolismo , Etilenoglicóis , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Fatores Sexuais , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/metabolismo , Tiazóis
15.
J Couns Psychol ; 66(1): 14-29, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30035589

RESUMO

[Correction Notice: An Erratum for this article was reported in Vol 66(1) of Journal of Counseling Psychology (see record 2018-66276-001). In the article "The development and psychometric evaluation of the Trans Discrimination Scale: TDS-21" by Laurel B. Watson, Luke R. Allen, Mirella J. Flores, Christine Serpe, and Michelle Farrell (Journal of Counseling Psychology, 2018, Advance online publication. http://dx.doi.org/10 .1037/cou0000301), there were two errors in the Methods section of the article. In Study 1, Participants paragraph of The development and psychometric evaluation of the Trans Discrimination Scale: TDS-21 for the Methods section, the gender listed at birth was incorrect in the following sentence, The majority of participants in this study identified as trans women and along a trans feminine spectrum, were assigned male at birth, White, had attained some college but no degree, and were employed full time. The correct gender assigned at birth was predominantly female. In addition, the gender coding procedures was incorrectly described. Specifically, those who identified as FAAB and AFAB were actually coded as trans men or along a transmasculine spectrum, whereas those who identified as MAAB and AMAB were coded as trans women and along a trans feminine perspective. In Study 3, Participants paragraph of The development and psychometric evaluation of the Trans Discrimination Scale: TDS-21 for the Methods section, the gender identity listed in the following sentence was incorrect, The majority of participants identified as trans women and along the trans feminine spectrum, were assigned female at birth, White, had attained some college but no degree, and were students. Rather, participants primarily identified as non-binary trans.] To date, researchers assessing the role of discrimination in trans peoples' lives have relied upon measures that were developed and normed on LGB populations, culled specific items from large-scale survey data, or used more generalized measures of discrimination that do not specifically assess the unique forms of discrimination that trans people may encounter. Thus, the purpose of this three-part study was to develop and provide psychometric support for a measure of trans peoples' discrimination. In Study 1, a five-factor model emerged, which included: Microaggressions and Harassment, Restricted Career and Work Opportunities, Maltreatment in Health Care Settings, Harassment by Law Enforcement, and Bullying and Harassment in Educational Settings. Internal consistency estimates for subscale and total scale scores ranged from acceptable to excellent. Results from Study 2 revealed that a bifactor model provided the best fit to the data, revealing that the scale is essentially unidimensional. In addition, convergent and concurrent validity was supported, demonstrating significant positive correlations with another measure of trans discrimination, internalized transphobia, nondisclosure, negative expectations for the future, psychological distress, and perceived stress. In Study 3, results revealed excellent test-retest reliability up to a three-week period. Collectively, results suggested that the Transgender Discrimination Scale-21 (TDS-21) is a psychometrically sound measure that may be used to advance research on the role of discrimination in trans peoples' lives. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Sexismo/psicologia , Inquéritos e Questionários/normas , Pessoas Transgênero/psicologia , Transexualidade/diagnóstico , Transexualidade/psicologia , Adulto , Feminino , Identidade de Gênero , Humanos , Idioma , Masculino , Pessoa de Meia-Idade , Percepção/fisiologia , Psicometria/estatística & dados numéricos , Reprodutibilidade dos Testes , Sexismo/prevenção & controle , Adulto Jovem
16.
Neurology ; 91(19): e1809-e1821, 2018 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-30305451

RESUMO

OBJECTIVE: To assess whether global or regional changes in amyloid burden over 4 years predict early declines in episodic memory in initially amyloid-negative adults. METHODS: One hundred twenty-six initially amyloid-negative, cognitively normal participants (age 30-89 years) were included from the Dallas Lifespan Brain Study who completed florbetapir PET and a cognitive battery at baseline and 4-year follow-up. Standardized uptake value ratio (SUVR) change was computed across 8 bilateral regions of interest. Using general linear models, we examined the relationship between change in global and regional SUVR and change in episodic memory, controlling for baseline SUVR, baseline memory, age, sex, education, and APOE status. RESULTS: In initially amyloid-negative adults, we detected a regionally specific relationship between declining episodic memory and increasing amyloid accumulation across multiple posterior cortical regions. In addition, these amyloid-related changes in memory persisted when we focused on middle-aged adults only and after controlling for atrophy in global cortical, hippocampal, and Alzheimer disease signature cortical volume. CONCLUSION: Our results indicate that assessing regional changes in amyloid, particularly in posterior cortical regions, can aid in the early detection of subclinical amyloid-related decline in episodic memory as early as middle age. Future research incorporating tau and other markers of neurodegeneration is needed to clarify the sequence of events that lead to this early, subclinical memory decline.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Encéfalo/patologia , Disfunção Cognitiva/patologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/metabolismo , Disfunção Cognitiva/metabolismo , Feminino , Humanos , Estudos Longitudinais , Masculino , Memória Episódica , Pessoa de Meia-Idade
17.
Neurobiol Aging ; 68: 114-122, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29602495

RESUMO

The fornix and parahippocampal cingulum are 2 major limbic tracts in the core memory network of the hippocampus. Although these fiber tracts are known to degrade with Alzheimer's disease (AD), little is known about their vulnerability in the asymptomatic phase of AD. In this longitudinal study of cognitively normal adults, we assessed amyloid-beta (Aß) plaques using positron emission tomography and white matter microstructure using diffusion tensor imaging. We found that an increase of neocortical Aß burden over time was associated with an increase of radial diffusivity in the fornix but not in the parahippocampal cingulum. The effect of increasing neocortical Aß burden on the fornix remained significant after controlling for baseline measures, head motion, global brain atrophy, regional Aß burden in the hippocampus, or microstructural changes in the global white matter. In addition, microstructural changes in the fornix were not associated with decline of episodic memory or other cognitive abilities. Our findings suggest that microstructural changes in the fornix may be an early sign in the asymptomatic phase of AD.


Assuntos
Envelhecimento/metabolismo , Envelhecimento/patologia , Peptídeos beta-Amiloides/metabolismo , Cognição , Fórnice/metabolismo , Idoso , Idoso de 80 Anos ou mais , Envelhecimento/psicologia , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Imagem de Tensor de Difusão , Diagnóstico Precoce , Feminino , Fórnice/diagnóstico por imagem , Fórnice/patologia , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Substância Branca/diagnóstico por imagem , Substância Branca/metabolismo , Substância Branca/patologia
18.
J Couns Psychol ; 65(3): 308-323, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29672081

RESUMO

The purpose of this grounded theory study was to investigate transgender people of color's (TPOC's) sexual objectification experiences (SOEs). Fifteen TPOC were interviewed about their experiences with sexual objectification. Using intersectionality and objectification theories as our research paradigms, results suggested that participants' SOEs were shaped by the intersections of cissexism, sexism, and racism, and that participants experienced various levels of privilege and oppression based on their specific identities. Results revealed similarities with previous sexual objectification research as well as unique sexual objectification experiences for TPOC, including racialized sexual objectification, fetishization, genital- and gender transition-based comments, and body policing. Results also suggested that self-objectification may manifest as a desire to affirm one's gender identity and result in physical safety anxiety. TPOC may engage in body surveillance to achieve transgender congruence and reduce potential victimization experiences. Mental health practitioners are encouraged to attend to how intersections of cissexism, sexism, and racism may encourage SOEs, and the ways in which such experiences may impact TPOC. (PsycINFO Database Record


Assuntos
Adaptação Psicológica , Racismo/psicologia , Sexismo/psicologia , Comportamento Sexual/psicologia , Pigmentação da Pele , Pessoas Transgênero/psicologia , Adolescente , Adulto , Ansiedade/epidemiologia , Ansiedade/psicologia , Feminino , Identidade de Gênero , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
19.
JAMA Neurol ; 74(7): 830-838, 2017 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-28558099

RESUMO

Importance: Presently, the clinical standard for reporting the results of an amyloid positron emission tomography scan is to assign a dichotomous rating of positive or negative for the presence of amyloid. In a 4-year longitudinal study, we investigated whether using a continuous measure of the magnitude of baseline amyloid burden would provide valuable information about the rate of future cognitive decline over the subsequent 4 years compared with a dichotomous measure in middle-aged and older adults. Objective: To examine whether a continuous, dose-response relationship between amyloid burden and cognitive decline was present among middle-aged and older adults. Design, Setting, and Participants: This cohort study included 174 participants from the Dallas Lifespan Brain Study who were 40 to 89 years old at the beginning of the study, were cognitively normal at baseline (a Mini-Mental State Examination score of 26 or higher) with no history of neurological or psychiatric disorders, and had completed amyloid imaging ([18F]-florbetapir) at baseline and cognitive assessments at baseline and a 4-year follow-up. Continuous amyloid burden was measured as the mean cortical standardized uptake value ratio (SUVR) at baseline. Main Outcomes and Measures: Linear mixed models assessed the effect of increasing baseline amyloid over time (SUVR × time interaction) on episodic memory, reasoning, processing speed, vocabulary, and Mini-Mental State Examination performance. Age, sex, education, apolipoprotein ε4, and the random effect of intercepts were included as covariates. Results: The mean (SD) age for all participants (n = 174) was 66.44 (11.74) years, and 65 participants (37%) were men. The primary analyses yielded significant SUVR × time interactions in episodic memory, processing speed, vocabulary, and Mini-Mental State Examination performance, but not in reasoning performance. Higher baseline SUVR projected greater cognitive decline over 4 years. When controlling for variance related to a dichotomized positive/negative classification, most effects on cognition remained. Dichotomized amyloid status alone yielded fewer significant effects of amyloid on cognitive decline than continuous SUVR. Among amyloid-positive participants, increasing baseline SUVR predicted an increasing decline in episodic memory, but other effects on cognition were more limited. Finally, higher baseline amyloid burden among middle-aged adults was related to changes in vocabulary, with the effect driven by 3 apolipoprotein ε4 homozygotes. Conclusions and Relevance: These results suggest that the magnitude of amyloid burden at baseline is associated with the rate of cognitive decline over 4 years and potentially provides important information about the rate of future cognitive decline that is not available from a dichotomous positive/negative categorization.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Disfunção Cognitiva , Progressão da Doença , Adulto , Idoso , Idoso de 80 Anos ou mais , Compostos de Anilina , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/metabolismo , Disfunção Cognitiva/fisiopatologia , Etilenoglicóis , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons
20.
Neurobiol Aging ; 46: 68-75, 2016 10.
Artigo em Inglês | MEDLINE | ID: mdl-27460151

RESUMO

Measures of core cognitive processes (fluid abilities) are highly correlated with measures of knowledge (crystallized abilities) in healthy adults. In early stages of Alzheimer's disease (AD), fluid abilities, however, decline more rapidly than crystallized abilities. We hypothesized that cognitively normal older adults who evidenced lower fluid ability compared with crystallized ability (an ability discrepancy) would show evidence of early AD neuropathology indexed via in vivo measures of amyloid-beta (Aß) deposition and cortical thickness in AD-vulnerable regions. A sample of older adults (n = 112) aged 65 to 89 underwent a cognitive battery, structural magnetic resonance imaging, and a subset (n = 75) also completed positron emission tomography scanning to measure Aß deposition using F-18 Florbetapir. Of this sample, 60 older adults (43 with available positron emission tomography scans) evidenced a discrepancy where fluid ability was lower than crystallized ability. The magnitude of the ability discrepancy was independently associated with a greater Aß deposition and thinner cortex in AD-vulnerable regions, as well as age. The data suggest that such a discrepancy may be a marker of preclinical AD.


Assuntos
Envelhecimento/patologia , Envelhecimento/psicologia , Doença de Alzheimer/patologia , Doença de Alzheimer/psicologia , Cognição/fisiologia , Reconhecimento Psicológico/fisiologia , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Biomarcadores , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Neuroimagem , Tomografia por Emissão de Pósitrons
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