Citations

Abstract The standard approach to quantify amyloid (Aβ) PET averages uptake within a single cortical mask that assumes no clinically relevant spatial heterogeneity in uptake patterns. Here, in a sample of 12,379 clinically impaired participants taken from four phenotypically diverse cohorts we use data-driven approaches to discover heterogeneous patterns of Aβ-PET binding, uncovering a reproducible and clinically relevant pattern of posterior predominant Aβ-PET binding. In particular, Aβ-PET positive participants who have posterior predominant binding are less likely to be APOE -ε4 carriers, more severely impaired, have thinner cortex in posterior regions, and greater posterior tau PET burden. Furthermore, in a subsample of participants with neuropathological assessment, participants with posterior predominant Aβ binding have a higher likelihood of having cerebral amyloid angiopathy at autopsy. These findings suggest that Aβ-PET accumulates along two orthogonal axes with biological and clinical relevance, indicating that the standard approach to assess Aβ-PET is insufficient to capture meaningful signal from Aβ-PET imaging. This work has implications for the diagnosis and treatment of Alzheimer’s disease and extends our understanding of the mechanisms governing variable Aβ-PET distribution and its downstream effects.

Abstract Patients with atypical variants of Alzheimer's disease (AD) often present at a younger age with predominantly non‐amnestic impairments and a more aggressive disease course. Historically, individuals with atypical presentations have not been included in large‐scale clinical trials, which typically focus on late‐onset, sporadic amnestic‐predominant AD. Consequently, treatment options and research efforts specific to atypical AD remain limited. The emergence of amyloid‐targeting therapies that slow disease progression underscores these challenges, as evidence supporting their efficacy in early‐onset amnestic and non‐amnestic AD variants is scarce. This perspective article argues that atypical AD represents an excellent disease model for clinical trials and proposes strategies to address critical gaps in clinical trial design for this population. Key considerations include optimizing participant selection approaches, establishing syndrome‐specific or surrogate biological and clinical endpoints, and fostering advocacy to enhance early and accurate diagnosis, equitable representation, and outcomes for these populations.

Importance TMEM106B is a frontotemporal lobar degeneration (FTLD) genetic susceptibility factor, and TMEM106B protein aggregates are a feature of aging and neurodegeneration. Whether TMEM106B protein levels are associated with clinical features is unknown. Objective To investigate the clinical associations of cerebrospinal fluid (CSF) TMEM106B in FTLD. Design, Setting, and Participants This cross-sectional study was conducted in 2 independent frontotemporal dementia (FTD) cohorts (recruitment from April 2009 through July 2023, with analyses from January 2025 through April 2026), with a 2-year follow up. This multicenter clinical study integrated clinical, genetic, biomarker, and neuroimaging data. Individuals were recruited through the University of California, San Francisco (n = 3733), or ALLFTD (n = 2343). Participants with available CSF were included. A discovery cohort (n = 271) included participants with sporadic neuropathology-confirmed FTLD; presymptomatic or symptomatic carriers of pathogenic variants in C9orf72 , GRN , or MAPT ; or controls. An independent validation cohort (n = 383) included participants with clinically diagnosed sporadic FTD, Alzheimer disease (AD), and controls. Exposures CSF samples for TMEM106B quantification with aptamer proteomics (SomaScan version 3.0 [discovery cohort] and SomaScan version 4.1 [validation cohort]). Main Outcomes and Measures Parametric tests compared the primary outcome, CSF TMEM106B, by disease severity, TMEM106B rs1990622 genotype, sex, clinical syndrome, pathological diagnosis, and pathogenic variant and determined associations with brain volume. Results In the discovery (n = 271; 136 women [51%]; median [IQR] age, 59 [38-80] years) and validation (n = 383; 183 women [48%]; median [IQR] age, 64 [50-78] years) cohorts, lower CSF TMEM106B was associated with more severe disease (β, −0.15; 95% CI, −0.24 to −0.04; P = .003), lower frontotemporal brain volumes (β, 0.42; 95% CI, 0.24-0.61; P < .001), and faster clinical progression (β, −2.21; 95% CI, −3.70 to −0.72; P = .001). Associations of TMEM106B with clinical disease severity were independent of those with neurofilament light chain. TMEM106B levels were influenced by TMEM106B rs1990622 genotype, where individuals with the protective G/G genotype had lower levels than the risk A/A genotype. CSF TMEM106B levels did not differentiate between FTLD subtypes or between FTLD and AD. Conclusions and Relevance Per the results of this cross-sectional study, TMEM106B is detectable in CSF and levels reflect disease severity in sporadic and genetic FTLD and AD, but levels are also influenced by the TMEM106B rs1990622 genotype. CSF TMEM106B could support further studies to understand the mechanisms of disease and develop clinical tools in FTLD and other neurodegenerative diseases.

Abstract Background Sleep disturbances are common in Alzheimer's disease and have been reported in its preclinical stage. A detailed characterization of sleep disruption across the Alzheimer’s disease continuum is required to clarify its role as a potential therapeutic target and to evaluate the utility of sleep-related biomarkers. Methods Sleep architecture was characterized through detailed spectral and temporal analysis of the slow-wave activity using polysomnography across the Alzheimer’s disease continuum . Participants included: cognitively unimpaired individuals without abnormal Alzheimer’s disease biomarkers (n = 30), cognitively unimpaired individuals with abnormal Alzheimer’s disease biomarkers (n = 45), and individuals with mild cognitive impairment or mild dementia due to Alzheimer’s disease (n = 41). Associations between slow-wave features and longitudinal cognitive performance were tested in cognitively unimpaired participants. Sex differences were also explored. Results A stepwise increased wake after sleep onset and latency to rapid eye movement sleep was observed, alongside reduced spectral power of slow-wave activity and a progressive flattening of slow-waves across the Alzheimer’s disease continuum in both sexes. In cognitively unimpaired individuals, higher slow-wave slope and greater peak-to-peak amplitude were associated with better cognitive trajectories over time. Conclusions Sleep macro- and microarchitecture are altered early and progressively deteriorate across the Alzheimer’s disease continuum . Slow-wave features relate to cognitive trajectories in preclinical Alzheimer’s disease, with exploratory analyses suggesting stronger associations in men. These findings support slow-wave morphology as a candidate non-invasive marker for future sleep-based intervention studies.

Abstract Since 2016, the Alzheimer's Association and the Fondation Alzheimer have hosted Global Alzheimer's Leadership Series (GoALS) global think tanks, with world‐leading experts for innovative discussions to advance Alzheimer's disease (AD) research and care. The second GoALS think tank, held in June 2024 in Paris, focused on the relationship between biological changes and clinical manifestations of AD in the context of the evolving therapeutic landscape. Discussions spanned real‐world experiences of providers, patients, and their families, theoretical considerations, and health system challenges. The lived experience perspective was central to these discussions. The importance of shared decision‐making, clear and transparent communication, and the need for real‐world data to holistically support patients during their experiences were highlighted. This manuscript shares key insights from both the think tank meeting in Paris and a featured research session at the 2024 Alzheimer's Association International Conference that expanded the discussion themes for broader dissemination with the community.

Abstract INTRODUCTION Clinicopathological studies offer crucial interpretations of 18 F‐flortaucipir (FTP) tau positron emission tomography (PET) signal but are limited by methods. We leveraged whole‐brain, quantitative immunohistochemical (IHC) Alzheimer's Disease (AD) tau density maps to comprehensively evaluate the FTP tracer. METHODS We generated IHC maps for three AD‐tau antibodies—AT8, AT100, and MC1—using two human brains histologically staged at Braak IV and VI. FTP‐PET scans were acquired 6 and 10 weeks prior to death. Using region‐wise and voxelwise methods, we correlated FTP‐PET with IHC signals. RESULTS Only AT8 (p‐tau Ser202/Thr205; neuronal and neuritic tau pathology) showed a notable correlation with FTP standardized uptake value ratios (SUVRs) in the Braak VI case (Spearman's rank correlation coefficient [r s ] = 0.461, p < 0.001). FTP SUVRs failed to capture medial temporal lobe (MTL) tau burden, whereas neocortical regions showed lower IHC burden but more variability in FTP uptake. DISCUSSION Although FTP signals correlate well with AT8‐positive tau in the more advanced case, they underestimate the severity of MTL burden, potentially confounding assessments of tau‐targeted therapies.

Abstract INTRODUCTION Sleep and circadian rest–activity rhythm (RAR) disruption may bidirectionally relate to Alzheimer's disease (AD). Down syndrome (DS), the most common genetic cause of AD, presents sleep disorders, yet RAR patterns across the DS‐associated AD continuum remain uncharacterized. METHODS We analyzed 7‐day wrist actigraphy in 140 adults with DS (108 asymptomatic; 32 AD dementia) and 41 unimpaired controls. General linear models, adjusted for age, sex, sleep efficiency, and obstructive sleep apnea (OSA) severity, tested group differences, with interaction terms included to evaluate group‐specific associations. RESULTS DS showed lower relative amplitude and higher nocturnal activity, already in asymptomatic individuals. Rhythm strength declined further with AD progression, while regularity and phase timing remained preserved until dementia. Findings were independent of sleep duration and OSA. DISCUSSION Adults with DS showed early RAR disturbance that progressed across the AD continuum, paralleling sporadic AD. Circadian RAR features may be scalable biomarkers of AD progression.

A bstract Alzheimer’s disease (AD) presents with substantial clinical and anatomical heterogeneity, including both typical amnestic and atypical variants such as posterior cortical atrophy and logopenic primary progressive aphasia. Although neurofibrillary tangle (NFT) burden is a defining pathological feature of AD, its regional distribution varies across clinical phenotypes, suggesting that selective neuronal vulnerability may shape disease presentation. However, the cellular and molecular determinants underlying this vulnerability remain incompletely understood. Here, we profiled single-nucleus transcriptomes across multiple brain regions, including hippocampal (CA1) and neocortical (superior temporal gyrus and occipital cortex) regions, from individuals with typical and atypical AD and healthy controls. Integrative analysis identified major cell classes and resolved diverse excitatory and inhibitory neuronal subpopulations that were reproducibly observed across regions and individuals. Using quasi-binomial regression models to assess compositional changes, we quantified subtype-specific vulnerability associated with AD pathology. We identified a distinct excitatory neuronal subpopulation characterized by NRGN and BEX1 expression, which showed reproducible depletion across multiple regions, with the strongest evidence in amnestic AD and in neocortical regions in lvPPA. This vulnerable population showed concordance with previously reported AD-associated excitatory neuron signatures, supporting a conserved transcriptional program of susceptibility. Genes enriched in this population were associated with chemical synaptic transmission and regulation of synaptic plasticity and formed interconnected networks in protein-protein interaction analyses. These findings suggest that intrinsic properties related to synaptic function may predispose specific neuronal populations to degeneration in AD. Together, our results define a conserved, transcriptionally distinct excitatory neuron subpopulation that is selectively vulnerable across AD phenotypes and brain regions. This work provides a framework for linking regional pathology to cell-type-specific susceptibility and highlights synaptic regulatory pathways as potential contributors to neuronal degeneration in Alzheimer’s disease.

Abstract Latin America is undergoing rapid population aging alongside a rising burden of dementia. While the region holds substantial potential for dementia risk reduction, challenges remain, such as delayed diagnoses, limited access to specialized care and biomarker testing, persistent stigma, and deep‐rooted structural inequities. To address these gaps and foster regionally informed solutions, the Alzheimer's Association convened the 2025 Alzheimer's Association International Conference (AAIC) Satellite Symposium in Lima, Peru, on May 14–15, in collaboration with the Global Brain Health Institute (GBHI) and the Atlantic Fellows for Equity in Brain Health. The meeting aimed to bring core elements of the global AAIC meeting to regional Latin American settings, recognizing that national and cultural contexts demand tailored approaches to dementia prevention, risk reduction, treatment and care all aimed at promoting brain health in the region. This manuscript synthesizes the symposium's key discussions, scientific advances, and opportunities for collaboration across the region.