Association of plasma Alzheimer's disease biomarkers with cognitive decline in cognitively unimpaired individuals.

Introduction: Plasma biomarkers' utility for predicting incident mild cognitive impairment (MCI) remains unclear. We evaluated associations of plasma Alzheimer's disease (AD) biomarkers and amyloid positron emission tomography (PET) with transitions from cognitively unimpaired (CU) to MCI in the Mayo Clinic Study of Aging (MCSA) and BioFINDER-2 studies.

Methods: Associations of continuous baseline plasma biomarker levels and amyloid PET Centiloid with progression to MCI, adjusting for age, sex, and education, were evaluated with Cox proportional hazards models.

Evaluation and interpretation of DTI-ALPS, a proposed surrogate marker for glymphatic clearance, in a large population-based sample.

Background: The diffusion tensor imaging along perivascular spaces index (DTI-ALPS), which measures diffusivity in the perivascular spaces along the medullary veins, has gained popularity and controversy as a surrogate marker of glymphatic clearance. The goal of this work is to automatically estimate DTI-ALPS in a large population-based sample, evaluate the correlates of the signal observed in the context of aging and dementia biomarkers, and evaluate its clinical usefulness.

Methods: We identified 2715 participants aged 30 + years in the population-based Mayo Clinic Study of Aging with diffusion MRI.

Combating Genetic Heterogeneity for Polygenic Prediction of Susceptibility to Brain β-Amyloid Deposition: Beyond .

Background And Objectives: The (apolipoprotein E) ε4 allele is the strongest known genetic risk factor for sporadic Alzheimer disease (AD) and for brain amyloidosis, an early marker of disease pathophysiology. However, ε4 is present in only 25% of the general population and is by itself inadequate for explaining susceptibility to amyloid accumulation or AD diagnosis. Existing studies have been limited by potential confounding due to inclusion of individuals carrying ε4 or ε2 (which has a modest protective association).

Plasma NfL and GFAP for predicting VCI and related brain changes in community and clinical cohorts.

Introduction: We investigated the usefulness of plasma neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) for capturing vascular cognitive impairment (VCI) in the context of amyloidosis.

Methods: Using two independent cohorts (n = 1810), we assessed the relationship of plasma NfL and GFAP with (1) vascular brain indices; (2) diagnostic states using the following definitions: vascular versus not (white matter hyperintensity/total intracranial volume ≥ 1.3%), and cognitively impaired (CI) versus cognitively unimpaired (CU) using Clinical Dementia Rating ([CDR] scale ≥ 0.

Frequency and Clinical Outcomes Associated With Tau Positron Emission Tomography Positivity.

Importance: Tau positron emission tomography (PET) allows in vivo detection of neurofibrillary tangles, a core neuropathologic feature of Alzheimer disease (AD).

Objective: To provide estimates of the frequency of tau PET positivity and its associated risk of clinical outcomes.

Design, Setting, And Participants: Longitudinal study using data pooled from 21 cohorts, comprising a convenience sample of 6514 participants from 13 countries, collected between January 2013 and June 2024.

Impact of cardiovascular risk factors on plasma biomarkers in prediction of Alzheimer's and cerebrovascular neuropathology.

Background: Plasma biomarkers for Alzheimer's disease and neurodegeneration have shown accurate prediction of underlying neuropathology. However, chronic cardiovascular risk factors such as diabetes and hypertension are associated with plasma biomarker levels and can influence the accurate prediction of underlying neuropathologic changes.

Objective: To understand the interaction between plasma biomarkers of Alzheimer's disease and neurodegeneration with cardiovascular risk factors in relation to neuropathologic change in a heterogenous population to ascertain a more accurate utilization of these biomarkers.

Associations between temporal lobe cortical NODDI measures and memory function in individuals without clinical dementia.

Introduction: Temporal cortical microstructural changes precede cortical atrophy during memory decline. We used neurite orientation dispersion and density imaging (NODDI) to assess such early microstructural change.

Methods: Cognitively unimpaired (CU, n = 725) and mildly cognitively impaired (MCI, n = 111) participants from the Mayo Clinic Study of Aging underwent 3T magnetic resonance imaging (MRI), including NODDI and neuropsychological evaluation for calculation of memory z scores.

Cortical microstructural abnormalities in dementia with Lewy bodies and their associations with Alzheimer's disease copathologies.

Dementia with Lewy bodies (DLB) frequently coexists with Alzheimer's disease pathology, yet the pattern of cortical microstructural injury and its relationship with amyloid, tau, and cerebrovascular pathologies remains unclear. We applied neurite orientation dispersion and density imaging (NODDI) to assess cortical microstructural integrity in 57 individuals within the DLB spectrum and 57 age- and sex-matched cognitively unimpaired controls by quantifying mean diffusivity (MD), tissue-weighted neurite density index (tNDI), orientation dispersion index (ODI), and free water fraction (FWF). Amyloid and tau levels were measured using PiB and Flortaucipir PET imaging.

Patterns of Factors in the National Institute on Aging Health Disparities Research Framework Domains and Mild Cognitive Impairment Risk.

Introduction: Alzheimer's disease and related dementias are public health and social care challenges. This study used the National Institute on Aging Health Disparities Research Framework to organize potential cognitive impairment risk factors. It aimed to examine patterns of environmental, sociocultural, behavioral, and biological factors and identify key components that predict mild cognitive impairment risk.

Amyloid PET in Sporadic Early- Versus Late-Onset Alzheimer's Disease: Comparison of the LEADS and ADNI Cohorts.

Objective: Early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease (LOAD) differ in many respects. Here, we address the issue of possible differences in fibrillar amyloid pathology as measured by positron emission tomography (PET), which remains unresolved due to the lack of large-scale comparative studies.

Methods: Three hundred ninety-nine cognitively impaired participants younger than 65 years of age from the multicenter Longitudinal Early-onset Alzheimer's Disease Study (LEADS) and 450 cognitively impaired participants older than 65 years from the Alzheimer's Disease Neuroimaging Initiative (ADNI) underwent clinical assessment, brain magnetic resonance imaging (MRI), and amyloid PET and were included in this study.

Sex Differences in Longitudinal Tau-PET in Preclinical Alzheimer Disease: A Meta-Analysis.

Importance: Alzheimer disease (AD) predominates in females at almost twice the rate relative to males. Mounting evidence in adults without AD indicates that females exhibit higher tau deposition than age-matched males, particularly in the setting of elevated β-amyloid (Aβ), but the evidence for sex differences in tau accumulation rates is inconclusive.

Objective: To examine whether female sex is associated with faster tau accumulation in the setting of high Aβ (as measured with positron emission tomography [PET]) and the moderating influence of sex on the association between APOEε4 carrier status and tau accumulation.

Plasma Alzheimer's disease biomarker relationships with incident abnormal amyloid PET.

Introduction: Limited data exist on the utility of plasma biomarkers to predict incident abnormal amyloid positron emission tomography (PET). In this study we evaluate the association of plasma Alzheimer's disease (AD) biomarkers with amyloid PET progression among initially amyloid PET negative (A-) individuals.

Methods: We included 290 A-, cognitively unimpaired Mayo Clinic Study of Aging participants.

Dissociable spatial topography of cortical atrophy in early-onset and late-onset Alzheimer's disease: A head-to-head comparison of the LEADS and ADNI cohorts.

Introduction: Early-onset and late-onset Alzheimer's disease (EOAD and LOAD, respectively) have distinct clinical manifestations, with prior work based on small samples suggesting unique patterns of neurodegeneration. The current study performed a head-to-head comparison of cortical atrophy in EOAD and LOAD, using two large and well-characterized cohorts (LEADS and ADNI).

Methods: We analyzed brain structural magnetic resonance imaging (MRI) data acquired from 377 sporadic EOAD patients and 317 sporadicLOAD patients who were amyloid positive and had mild cognitive impairment (MCI) or mild dementia (i.

Eligibility for donanemab trial in a population-based study of cognitive aging.

The study aimed to assess eligibility for donanemab phase 3 trial in participants of the Mayo Clinic Study of Aging with mild cognitive impairment (MCI) or mild dementia consistent with Alzheimer's disease (AD) clinical syndrome, positive brain amyloid burden, and available tau PET. There were 817 study participants, 60-85 years old, with MCI or dementia consistent with AD clinical syndrome. Applying the Mini-Mental State Examination criteria (20 to 28) and excluding participants with imaging contraindications reduced the sample to 769; 275 participants had amyloid PET available, of whom 130 had also tau PET at the same visit; 56 participants were amyloid positive, had tau PET available at the same visit, and of those, 27 had evidence of tau pathology measured by 18F-flortaucipir PET imaging.

Characterizing and validating 12-month reliable cognitive change in Early-Onset Alzheimer's Disease for use in clinical trials.

Background: As literature suggests that Early-Onset Alzheimer's Disease (EOAD) and late-onset AD may differ in important ways, need exists for randomized clinical trials for treatments tailored to EOAD. Accurately measuring reliable cognitive change in individual patients with EOAD will have great value for these trials.

Objectives: The current study sought to characterize and validate 12-month reliable change from the Longitudinal Early-Onset Alzheimer's Disease Study (LEADS) neuropsychological battery.

Heterogeneous clinical phenotypes of sporadic early-onset Alzheimer's disease: a neuropsychological data-driven approach.

Background: The clinical presentations of early-onset Alzheimer's disease (EOAD) and late-onset Alzheimer's disease are distinct, with EOAD having a more aggressive disease course with greater heterogeneity. Recent publications from the Longitudinal Early-Onset Alzheimer's Disease Study (LEADS) described EOAD as predominantly amnestic, though this phenotypic description was based solely on clinical judgment. To better understand the phenotypic range of EOAD presentation, we applied a neuropsychological data-driven method to subtype the LEADS cohort.

Dynamic proportional loss of functional connectivity revealed change of left superior frontal gyrus in subjective cognitive decline: an explanatory study based on Chinese and Western cohorts.

Brain network dynamics have been extensively explored in patients with subjective cognitive decline (SCD). However, these studies are susceptible to individual differences, scanning parameters, and other confounding factors. Therefore, how to reveal subtle SCD-related subtle changes remains unclear.

Rethinking the residual approach: leveraging statistical learning to operationalize cognitive resilience in Alzheimer's disease.

Cognitive resilience (CR) describes the phenomenon of individuals evading cognitive decline despite prominent Alzheimer's disease neuropathology. Operationalization and measurement of this latent construct is non-trivial as it cannot be directly observed. The residual approach has been widely applied to estimate CR, where the degree of resilience is estimated through a linear model's residuals.

Quantitative Assessment of the Effect of Chronic Kidney Disease on Plasma P-Tau217 Concentrations.

Background And Objectives: Chronic kidney disease (CKD) is known to be associated with increased plasma phosphorylated tau217 (p-tau217) concentrations, potentially confounding the utility of plasma p-tau217 measurements as a marker of amyloid pathology in individuals with suspected Alzheimer disease (AD). In this study, we quantitatively investigate the relationship of plasma p-tau217 concentrations vs estimated glomerular filtration rate (eGFR) in individuals with CKD with and without amyloid pathology.

Methods: This was a retrospective examination of data from 2 observational cohorts from either the Mayo Clinic Study of Aging or the Alzheimer's Disease Research Center cohorts.

Association of plasma biomarkers of Alzheimer's pathology and neurodegeneration with gait performance in older adults.

Background: Declining gait performance is seen in aging individuals, due to neural and systemic factors. Plasma biomarkers provide an accessible way to assess evolving brain changes; non-specific neurodegeneration (NfL, GFAP) or evolving Alzheimer's disease (Aβ 42/40 ratio, P-Tau181).

Methods: In a population-based cohort of older adults, we evaluate the hypothesis that plasma biomarkers of neurodegeneration and Alzheimer's Disease pathology are associated with worse gait performance.

Brain mechanical properties predict longitudinal cognitive change in aging and Alzheimer's disease.

Age-related cognitive decline is a complex phenomenon that is influenced by various neurobiological processes at the molecular, cellular, and tissue levels. The extent of this decline varies between individuals and the underlying determinants of these differences are not fully understood. Two of the most prominent signs of cognitive decline in aging are the deterioration of episodic memory, which is a hallmark of Alzheimer's disease (AD), and the nearly always accompanying atrophy of the medial temporal lobe.

The POINTER Imaging baseline cohort: Associations between multimodal neuroimaging biomarkers, cardiovascular health, and cognition.

Introduction: The U.S. Study to Protect Brain Health Through Lifestyle Intervention to Reduce Risk (U.

Positron emission tomography harmonization in the Alzheimer's Disease Neuroimaging Initiative: A scalable and rigorous approach to multisite amyloid and tau quantification.

Introduction: A key goal of the Alzheimer's Disease NeuroImaging Initiative (ADNI) positron emission tomography (PET) Core is to harmonize quantification of β-amyloid (Aβ) and tau PET image data across multiple scanners and tracers.

Methods: We developed an analysis pipeline (Berkeley PET Imaging Pipeline, B-PIP) for ADNI Aβ and tau PET images and applied it to PET data from other multisite studies. Steps include image pre-processing, refacing, magnetic resonance imaging (MRI)/PET co-registration, visual quality control (QC), quantification of tracer uptake, and standardization of Aβ and tau standardized uptake value ratios (SUVrs) across tracers.