Journal of Alzheimer’s Disease

Vascular dementia (VaD) is a complex clinical syndrome arising from cerebrovascular disease, characterized by cognitive decline and functional impairment, and is projected to double in prevalence over the next three decades. Deficiencies in one-carbon (1C) metabolism are linked to the onset of VaD. Our previous work using mouse models has demonstrated that reduced dietary folic acid intake or genetic disruptions in 1C metabolism exacerbate outcomes in a model of VaD. However, the impact of VaD on one-carbon metabolism remains poorly understood. This study aims to provide a detailed molecular portrait of 1C metabolism within the context of VaD, shedding light on potential molecular mechanisms. In post-mortem medial prefrontal cortex tissue from VaD female and male patients and controls we measured protein expression of the folate receptor (FR) and 1C enzymes including methylenetetrahydrofolate reductase (MTHFR), thymidylate synthase (TS), choline acetyltransferase (ChAT), acetylcholinesterase (AChE), cystathionine {beta}-synthase (CBS) co-localized with NeuN. There was an interaction between VaD and gender for levels of FR. Both male and female VaD had increased levels of ChAT. Female VaD patients had higher levels of MTHFR and CBS when compared to males. VaD is a complex disease; the results of this study demonstrate that VaD impacts neuronal levels of 1C enzymes. Future studies should assess 1C in other cell types of the brain, as well as measure enzyme activity levels.

Persistent racial disparities in dementia raise concerns regarding the validity and generalizability of existing prognostic models across diverse populations. We evaluated the utility of the 2024 Lancet Commission risk factors and resting heart rate (RHR) for race-specific dementia risk prediction using data from 55,004 participants in the National Alzheimer's Coordinating Center cohort. Cox proportional hazards and Random Survival Forest (RSF) models were developed separately for Black, White, Asian, and American Indian participants to predict 1-, 3-, and 5-year time to dementia. RSF consistently outperformed Cox models across all racial groups and prediction horizons, achieving 5-year AUCs of 0.88-0.91 compared with 0.69-0.81 for Cox models. Inclusion of RHR modestly and consistently improved predictive performance across racial groups. Predictor importance varied between racial groups, suggesting heterogeneity in dementia risk profiles and disease presentation. These findings support the potential utility of RHR as a complementary prognostic biomarker and highlight the importance of equitable, personalized dementia risk prediction across diverse populations.

Impairment in the comprehension of morphosyntactic and transitivity information does not feature in current diagnostic guidelines for primary progressive aphasia (PPA) or Alzheimer's Disease (AD), despite research reporting delayed sensitivity or insensitivity of these clinical populations to these linguistic domains. Moreover, studies rarely compare all three PPA variants and AD within a single design, and the literature is weighted toward English, whose reduced morphology may not capture the full range of comprehension difficulties these populations experience. We developed a computer-based acceptability judgment task covering comprehension of the nominal and verbal inflection paradigm in Spanish, transitivity and word order. We recruited Spanish-speaking patients diagnosed with non-fluent/agrammatic, logopenic and semantic variants of PPA and typical AD. Psychometric evaluation confirmed good sensitivity, internal consistency and moderate correlation of task accuracy with language and neuropsychological measures. The four clinical groups retained the ability to endorse grammatical sentences but showed selective difficulty rejecting unacceptable ones. AD and the three PPA variants showed impaired comprehension of inflectional and transitivity information, whereas sensitivity to word order was comparatively preserved. Exploratory analyses revealed that short-term memory, working memory, and verbal semantics were differentially associated with sentence evaluation performance within and across groups. VBM analyses identified the left posterior temporal cortex as the main neuroanatomical correlate of grammaticality judgment performance. These findings extend prior English-language research to Spanish, demonstrating that morphosyntactic and transitivity deficits are a robust and cross-linguistically consistent feature of neurodegenerative language decline, and highlighting the importance of developing language-sensitive assessment tools for underrepresented linguistic populations.

Background: Alzheimer's Disease and Related Dementias (ADRD) is a growing global public health challenge, and caregivers experience high rates of burden, unmet needs, and system failures. These challenges vary by caregiver role and relationship to the care recipient, reflecting the heterogeneous nature of caregiving. Yet prior work has largely studied burden, unmet needs, and system failures as separate domains rather than examining how they co-occur within individual caregivers. Methods: We applied an LLM-based classification framework (Claude 3.5 Sonnet) to 7,198 posts from three ALZConnected caregiver forums (general, spouse/partner, and adult child caregivers), coding each post for burden, unmet needs, and system failures across 9, 12, and 10 categories respectively. We compared expression rates by caregiver role (primary vs. secondary) and relationship to the care recipient (spousal vs. child) and used post-level co-occurrence networks to map how categories cluster within and across domains. Results: Burden was expressed in 89.0% of posts and unmet needs in 93.3%, while system failures appeared in 34.8%. Primary caregivers reported burden more often than secondary caregivers (91.6% vs. 84.7%), while secondary caregivers reported more unmet needs (94.6% vs. 92.5%) and more system failures (37.2% vs. 33.4%). Child caregivers reported higher rates than spousal caregivers across all three domains. Co-occurrence networks showed dense within-domain clustering (density 0.61-0.65) and 84 significant cross-domain connections, with the strongest links between behavioral/safety burden and safety-management needs (21.7% of posts) and between emotional burden and emotional-support needs (20.9%). Conclusion: Burden, unmet needs, and system failures are not independent problems but form interconnected challenge ecosystems that vary by caregiver role and relationship. This suggests caregiver support should be designed around these connected patterns rather than treated as separate, single-domain interventions.

INTRODUCTION: Neurodegenerative research identifies biomarkers to confirm presence of disease and inform about risk for clinical symptoms. Expert guidance advises caution about disclosing individual research results (IRR), but participant interest remains high even when IRR may not inform individual prognosis. Existing studies of stakeholder attitudes emphasize Alzheimer's disease (AD) biomarkers. We explore participant attitudes toward IRR from the United States CADASIL Consortium (USCC), an observational study of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL), the most heritable form of vascular dementia. METHODS: Since CADASIL research participant attitudes are unstudied and AD-focused guidelines for IRR may not generalize to populations with dominantly inherited conditions, we surveyed USCC participants using three 5-point Likert items and one open-ended question. Descriptive statistics were analyzed for Likert items. The distribution of responses to one item was directly compared to an AD participant survey. Open-ended responses underwent qualitative content analysis. RESULTS: We received 152 responses. The highest-rated reason to return IRR was "learn about my disease and its predicted course". The highest-rated IRR were imaging/MRI scans and cognitive testing. Hypothetical negative outcomes were rated as a little to somewhat concerning. USCC respondents rated reasons to return IRR higher than AD counterparts, with statistically significant differences for seven of eight items. In open-ended responses, the most frequent code was "IRR return will help improve my health and well-being". DISCUSSION: Most respondents expressed support for disclosure upon participant request. These findings could inform IRR guidance for CADASIL and other disorders and investigations of personal utility.

Importance. Metformin may influence risk of dementia, with prior conflicting observations of protection or harm. Objective. To determine the association of randomization to metformin vs. placebo or intensive lifestyle intervention (ILS) in the Diabetes Prevention Program (DPP) with cognitive outcomes (cognitive impairment syndromes and trajectories of cognitive test performance) during the DPP Outcomes Study (DPPOS). Design, Setting & Participants. Prospective long-term follow-up of DPP/DPPOS participants at 27 U.S. centers among adults who were at high risk for type 2 diabetes (T2D) at baseline. Exposures. Randomization to metformin, placebo, or ILS (1996-1999) for 3.2 years followed by open-label metformin in the original randomized metformin group until 2021. Main Outcomes & Measures. Cognitive impairment syndromes were adjudicated in 2022-2024 in 1,483 participants (median age 74 [IQR 68, 80]) using the National Alzheimer's Coordinating Center Uniform Dataset version 3. Cognitive performance in executive and memory domains was ascertained with repeated cognitive tests between 2009 and 2024. Multinomial logistic regression and mixed-effects models were fit to examine associations of randomization to metformin with cognitive outcomes. Results. Total metformin exposure (mean {+/-} SD) was 15.5 {+/-}7.7 years/person in the metformin group. Persons in the placebo and ILS groups received out-of-study metformin usually after developing diabetes with mean metformin total exposure of 4.5 {+/-}5.1 and 3.8 {+/-}4.8 years/person in the placebo and ILS groups, respectively. Overall, the frequency distributions of the cognitive syndromes did not differ significantly by treatment group; however, randomization to metformin was associated with a 60% (OR 0.40 [95%CI 0.17, 0.97]) and 62% (OR 0.38 [95%CI 0.16, 0.89]) lower odds of dementia compared with placebo and ILS, respectively, after adjustment for demographics, education, income, and APOE-{varepsilon}4 genotype. Randomization to metformin was also associated with significantly better memory performance over time ( {beta} =0.58; 95%CI: 0.09, 1.1; p=0.02; Cohen's d=0.1). Conclusions and Relevance. Long-term metformin treatment is associated with a reduced risk of dementia and better memory performance among persons with pre-diabetes or T2D. Estimates were imprecise due to a limited number of dementia cases. Longer follow-up with more dementia cases is needed to confirm our findings.

Insulin resistance is increasingly recognized as a metabolic factor associated with Alzheimers disease (AD); however, its relevance to hippocampal structural changes--a key pathological feature of AD--across disease stages is not fully understood. To address this issue, we investigated the relationship between insulin resistance, hippocampal gray matter volume, and cognitive performance using data from the Alzheimers Disease Neuroimaging Initiative (ADNI), a large-scale neuroimaging dataset. Insulin resistance was assessed using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), and its relationship with brain structure and cognitive performance was evaluated across diagnostic groups. In the mild cognitive impairment (MCI) group, higher insulin resistance was associated with larger anterior hippocampal gray matter volume, whereas in the AD group this association was reversed in direction. Furthermore, in the MCI group, anterior hippocampal gray matter volume was also positively associated with higher Mini-Mental State Examination (MMSE) scores, and an exploratory mediation analysis suggested a significant indirect association linking HOMA-IR, anterior hippocampal volume, and cognitive performance through anterior hippocampal volume. These findings suggest that the relationship between insulin resistance and AD-related brain changes differs across diagnostic groups, highlighting the importance of considering metabolic alterations in relation to disease status.

Importance: Patients are increasingly learning Alzheimers disease (AD) genetic and biomarker results through electronic health portals. Evaluation of alternative scalable delivery models for return of AD risk information is needed to best support patient understanding and psychological well-being. Objective: To determine whether a patient-centered digital platform is comparable to clinician-mediated telehealth sessions for returning APOE and plasma pTau-217 results on outcomes of knowledge and psychological well-being. Design: The Evaluation of Self-Mediated Alternatives for Risk Testing Education and Return of Results (eSMARTER) study was a noninferiority trial of a patient-centered digital platform compared to clinician-mediated disclosure of APOE genotype and optional pTau-217 disclosure. Setting: Decentralized, fully remote trial enrolled participants in the contiguous United States (U.S.) between October 2024 and February 2025, with follow-up completed in November 2025. Participants: Eligible participants were aged 60-80 and had previously undergone APOE genotyping (without disclosure) via the GeneMatch program, passed psychological screening, had internet access, and were English-speaking. Interventions: Participants were randomized, 2:1, to the eSMARTER digital platform or clinician-mediated disclosure of APOE genotype. Following the 6-month post-APOE assessment, participants were offered optional pTau-217 disclosure via the same randomized modality. Main Outcomes and Measures: Primary outcomes at 1-7 days following APOE disclosure included changes in anxiety, disease-specific distress, and AD-related knowledge within a priori non-inferiority margins. Results: 674 persons (mean [SD] age 68 [4.7] years; 451 [67%] female; mean [SD] telephone MoCA=19 [2]) were eligible and provided demographic information. 651 participants were randomized to clinician-mediated (n=216) or digital disclosure (n=435) and completed APOE disclosure (66 [10%] APOE4 homozygotes, 377 [58%] heterozygotes, 208 [32%] non-carriers). 604 participants completed the study; 500 completed optional pTau-217 disclosure. Baseline characteristics were balanced across groups. At 1-7 days following APOE disclosure, scores on AD-related knowledge, PROMIS Anxiety, and disease-specific distress measures met non-inferiority. Conclusions and Relevance: Disclosure of APOE genotype by the eSMARTER digital platform is non-inferior to clinician-mediated telehealth disclosure. No significant between group differences were found following disclosure of pTau-217 results. Together, these results suggest that this digital platform may provide an evidence-based scalable approach for returning AD genetic and biomarker results.

Studies in humans and murine models have pointed towards a possible link between metabolic syndrome, which shows insulin resistance and metabolic dysregulation, and Alzheimer's disease (AD) pathology marked by amyloid-beta (A{beta}) accumulation and hypometabolism in the brain. Yet, the underlying biological mechanisms by which metabolic syndrome affects these pathological changes in AD brain remain unknown. We hypothesized that insulin resistance is responsible for alterations in blood-brain barrier (BBB) transport of A{beta} peptides and glucose. This hypothesis was tested by employing radiolabeled ligands (125I-A{beta}40, 125I-A{beta}42, and 18F-FDG) in high-fat diet (HFD)-fed mouse models that manifest metabolic syndrome. Further, we assessed alterations in the expression of various molecular mediators within the brain microcapillaries harvested from both low-fat diet (LFD)-fed and HFD-fed mice. Our findings show that HFD-fed mice developed peripheral insulin resistance and obesity. In addition, HFD-fed mice demonstrated an increase in the influx rate of A{beta} peptides and a reduction in 18F-FDG (a glucose surrogate) influx rate compared to LFD-fed mice. These transport changes are associated with the increase in the BBB endothelial expression of RAGE (receptor to traffic A{beta} from plasma-to-brain) and reduction of GLUT1 (glucose transporter) expression in HFD-fed mice compared to LFD-fed mice. Moreover, disruption in insulin signaling, as indicated by reduced pAKT and pERK expression, was observed in HFD-fed mice. Inhibiting AKT or ERK phosphorylation resulted in similar changes in A{beta} and glucose uptake in polarized BBB endothelial cell monolayers in vitro. These results indicate that high-fat diet induced metabolic syndrome may lead to BBB dysfunction, characterized by increased plasma-to-brain A{beta} trafficking and diminished glucose transport at the BBB, thereby aggravating the expression of AD pathological hallmarks.

While loss of NMDA receptors (NMDARs) is associated with Alzheimers disease (AD) severity, the effect of sex or the relationship between regional NMDAR density and antemortem cognitive status across the AD spectrum has not been examined. We performed quantitative in vitro autoradiography of hippocampus, entorhinal cortex (EC), and parietal cortex using NMDAR and tau radioligands. Relationships between regional NMDAR density and cognitive status assessed by the Mini Mental State Exam (MMSE), and between NMDAR and tau density, were examined by bivariate correlations. In both sexes, the largest AD-related decreases in NMDAR density were observed in the CA1 field. However, there was a significant diagnosis by sex interaction driven by sex-specific changes in the mild cognitive impairment (MCI) stage, with lower NMDAR density in MCI women, but not MCI men relative to same-sex controls. Within diagnosis analyses revealed positive correlations between NMDAR density and MMSE scores and significant negative correlations between EC NMDAR and tau density, which was significant only in AD men. Our data show that changes in hippocampal NMDAR density across the AD continuum are modulated by sex and may contribute to the known sex differences in the clinical trajectory of the disease.

Low protein (LP) diets improve metabolic health in rodents and humans. In rodents, LP diets are typically implemented by replacing protein with carbohydrates like sucrose or cornstarch, keeping diets isocaloric. However, humans can choose from many different types of carbohydrate, and how dietary carbohydrate quality - the precise composition of the dietary sugars - impacts the response to dietary protein remains largely unexplored. Here, mice were fed control (21% protein) or LP (7% protein) diets with four different carbohydrate sources: sucrose, a 1:1 glucose/fructose mixture, glucose, or fructose. While LP diets improved metabolic health across all groups in male mice, carbohydrate quality also significantly altered specific health outcomes, with fructose-fed mice having the lowest body weight and adiposity of all control diets. In female mice, responses to LP diets were influenced by carbohydrate quality, with certain sugars inducing a stronger metabolic response to LP diets than previously seen. Finally, in female APP/PS1 mice, a model of Alzheimer's disease, we find that although LP diets reduce A-beta; plaque burden irrespective of carbohydrate type, dietary sugar type does influence spatial memory. Together, these results demonstrate that while dietary protein is a critical determinant of metabolic and neurological health, carbohydrate quality influences these outcomes in a sex-specific manner.

Background: Late-onset Alzheimer's disease (LOAD) comprises more than 95% of all AD cases. Transgenic, overexpression animal models have off target side effects, do not effectively produce the heterogeneity observed clinically in LOAD patients, and are therefore not best suited for preclinical therapeutic development. The Model Organism Development and Evaluation for Late-onset Alzheimer's Disease (MODEL-AD) Consortium was established to develop novel mouse strains to model human-relevant genetic and environmental risk factors for LOAD. Methylenetetrahydrofolate reductase (MTHFR) is an enzyme in the folate/methionine pathway. Variants in the MTHFR gene, notably 677C>T, are associated with ADRD, and we have previously shown the Mthfr677C>T mouse model phenocopies humans carrying the variant and develop cerebrovascular deficits. Methods: To examine the contributions of Mthfr677C>T in the context of late-onset Alzheimer's disease (LOAD), MODEL-AD created a novel mouse strain on the C57BL/6J (B6) background that was homozygous for Mthfr677C>T, in combination with humanized Abeta;, APOEe4, and Trem2*R47H (referred to as LOAD2.Mthfr677C>T). Mice were assessed over multiple ages for disease-relevant phenotypes. Regular behavior measurements and biometric samples were collected longitudinally to 24 months of age. Blood and brain tissue were collected for transcriptomics, proteomics, human disease correlation, and neuropathology. Results: Despite lacking hallmark pathologies such as amyloid deposition and significant neuroinflammation, compared to LOAD2 controls, LOAD2.Mthfr677C>T mice showed transcriptional and proteomic signatures in the brain that relate to the cerebrovasculature, myelination, and synaptic biology, similar to those seen in human LOAD patients. Conclusions: These data further support the use of the LOAD2.Mthfr677C>T mouse model to study aspects of ADRD such as cerebrovascular compromise.

Introduction. Neuropsychiatric symptoms (NPS), including aggression, psychosis, anxiety, apathy, and depression, affect up to 85% of individuals with Alzheimer's disease (AD) and are among its most disabling and costly manifestations, accelerating cognitive and functional decline, institutionalization, mortality, and healthcare costs. NPS prevalence has largely been characterized using self-reported race. Whether NPS differs across genetically defined ancestry groups and whether self-reported race obscures these differences remains unknown, limiting accurate risk stratification and treatment development. Methods. Using whole-genome sequencing data from 7,118 ADSP participants, we defined three NPS clusters from the NPI-Q: early psychosis (CDR 0.5-1), late psychosis (CDR 2-3), and affective symptoms. Genetic ancestry was inferred by principal component clustering, identifying six groups (EUR, AFR, EAS, SAS, AMR, ADMIXED), and compared with self-reported race/ethnicity. NPS prevalence was compared across genetic ancestry groups and genetic ancestry and self-reported race using Fisher's exact and regression models. Results. Genetic ancestry assignment differed markedly from self-reported race, affecting NPS prevalence estimates. NPS prevalence also differed across ancestry groups; affective symptoms were highest in EAS (90%) and SAS (77%) and lowest in AFR (66%), while psychosis was highest in EAS (74%) and SAS (70%) and lowest in AMR (55%) and EUR (56%), with similar patterns for early and late psychosis. Discussion. Genetically defined ancestry alters NPS prevalence estimates in AD, suggesting that standard race categories obscure population-level disease burden and compromise risk stratification, screening, and trial design. Ancestry-associated differences suggest partially distinct genetic and environmental drivers, underscoring the need to incorporate genetic ancestry into AD research and care.

Early identification of Alzheimer's disease and related dementias (ADRD) remains challenging despite its importance for timely intervention, management of modifiable risk factors, and care planning. We developed and evaluated ADRD onset prediction models using longitudinal electronic health records (EHRs) from the All of Us Research Program at clinically meaningful lead times of 6, 12, 24, and 36 months before diagnosis, benchmarking interpretable count-based representations against four publicly available pretrained clinical foundation models (CLMBR-T, GPT-style, LLaMA-style, and Mamba) across multiple ADRD phenotype definitions. Count-based models consistently achieved the highest discrimination and calibration across all cohorts and prediction horizons. Predictive performance declined with increasing lead time for all approaches; however, the performance gap between count-based and pretrained representations progressively narrowed, with foundation models achieving comparable AUROC of 0.719 (compared to the AUROC of 0.738 of count-based model) at the 36-month horizon while providing higher sensitivity and F1 scores under a fixed operating threshold. External validation with zero-shot evaluation on UChicago EHRs exhibited limited generalizability for count-based and pretrained clinical foundation model based representations. These findings demonstrate that transparent count-based EHR representations remain the strongest overall approach for ADRD onset prediction, while pretrained clinical foundation models provide complementary advantages for long-term risk identification and establish a benchmark for evaluating transferable clinical representations in temporal ADRD risk prediction.

Background: ACE variants are genetic risk factors for Alzheimer's disease (AD), potentially through reduced enzymatic activity and impaired amyloid {beta} hydrolysis. Objectives: To create a publicly available database of ACE variants relevant to ACE deficiency and AD, and to estimate the population frequency of damaging ACE variants and their impact on blood ACE levels. Methods: ACE variants were compiled from literature, public databases (VarSome, dbSNP, ClinVar, gnomAD), and sequencing data (WES/WGS) from 5147 Russian individuals. Variants were classified using a consensus in silico score (AlphaMissense, MetaRNN, EVE). Blood ACE levels were measured in 330 carriers of 64 different ACE mutations. Results: We identified 1682 unique ACE variants. Of these, 608 (36.2%) were classified as functionally damaging, including 17 signal peptide, 210 loss of function, and 381 missense variants. The estimated carrier frequency of damaging ACE variants was 2 % (1/50). Notably, 24 variants associated with experimentally confirmed reductions in blood ACE levels had a combined estimated carrier frequency of 3.9 % in the general population, calculated from cumulative gnomAD v4.1.0 allele frequencies under a rare-variant independence model. An open-access browser is available at https://ace-browser.com/. Conclusions: Variants associated with reduced blood ACE levels were estimated to be carried by approximately 1 in 25 individuals in the general population. This frequency is of the same order of magnitude as the 13.2% prevalence of Alzheimer's dementia in individuals aged 75-84 years (Alzheimer's Association, 2025), consistent with the hypothesis that ACE deficiency may represent an underrecognized contributor to late-onset AD susceptibility. The ACE mutations-AD browser and integrated genotype-phenotype data presented here provide a novel resource for future basic, translational, and clinical research on ACE-dependent AD.

INTRODUCTION: Tau pathology in Alzheimers disease preferentially afflicts excitatory neurons in the limbic and association cortices that utilize high levels of calcium signaling to perform cognitive operations. This includes the layer III pyramidal cells in the dorsolateral prefrontal cortex (dlPFC) that subserve higher cognition, which express the calcium-binding protein, calbindin, when young and healthy, but lose calbindin and develop tangles and degenerate in Alzheimers disease (AD). These data suggest that loss of calbindin may be associated with the emergence of tau pathology. However, the relationship between calbindin and early-stage, soluble tau pathology is challenging to study in human brains, as soluble pTau dephosphorylates within 15min postmortem. In contrast, the relationship between calbindin and soluble pT217-tau expression can be studied in aging macaques with naturally-occurring tau pathology, where perfusion fixation is possible to capture phosphorylation state in situ. METHODS: The current study used multiple-label-immunofluorescence to label MAP2-positive dlPFC layer III pyramidal cells for calbindin and pT217-tau in macaque brains across the adult age span (8-34.5yrs). The study employed a semi-automated CellProfiler workflow to identify labeled pyramidal cell dendrites the cellular compartment where tau pathology begins in AD. RESULTS: Calbindin expression decreased with age, while pT217Tau increased with age. Specifically, the ratio of calbindin/pT217-tau within a dendrite decreased with age, and was especially prominent in the aged macaques with long-term inflammatory disorders. DISCUSSION: These data suggest that the loss of calbindin in dendrites with advancing age, and especially with inflammation, contributes to the rise of tau pathology and the risk of AD.

Early identification of cognitive impairment remains challenging in settings where comprehensive cognitive and clinical assessments are not available. Acoustic and linguistic features in naturalistic speech may serve as useful behavioural markers of cognitive impairment, but the value of integrating these measures with cognitive assessment remains unclear. We tested whether combining acoustic and linguistic features from one-minute speech samples with multi-domain cognitive assessment (spanning attention, language, memory and executive functions) improves classification of cognitively unimpaired individuals from those with amnestic mild cognitive impairment or early-stage Alzheimer's Disease. Across multiple machine learning models, combining cognitive, acoustic and linguistic features yielded significantly better classification performance than models using cognitive or speech features alone (area under the curve = 0.96-0.98, both comparisons p < .05). This proof-of-concept study reveals that integrating speech-based measures with cognitive testing may improve identification of cognitive impairment, supporting the development of accessible and scalable multimodal screening tools for primary care.

INTRODUCTION: Novel capillary-blood collection methods have not yet been evaluated for a wide range of central nervous system (CNS) and neurodegenerative disease-related proteins. Biomarkers of Alzheimer's disease (AD) and related disorders (ADRD) collected from devices like the Tasso+, a minimally invasive upper-arm capillary blood collection device, must be compared to traditional venipuncture to assess for validity. METHODS: Participants underwent blood collection via traditional venipuncture and Tasso+ in a clinical research setting. The Nucleic Acid Linked Immuno-Sandwich Assay (NULISA) CNS panel was used for biomarker quantification in venous and Tasso-derived plasma. RESULTS: Eighty-three participants (age mean{+/-}SD 76.8{+/-}8.2 years, 79.5% cognitively unimpaired) completed blood collection. Little to no correlation was found between venous and Tasso+ plasma for p-tau217, but the correlation was improved by using a brain-derived (BD)-p-tau217/BD-p-tau181 ratio. Extremely strong correlations were found for neurofilament light (NfL) and glial fibrillary acidic protein (GFAP). Among the 131 biomarkers measured, 51 (38.9%) had a Pearson R [&ge;] 0.90; 27 (20.6%) had values between 0.70-0.90; 26 (19.9%) had values between 0.30-0.70; and 27 (20.6%) had values [&le;] 0.30. DISCUSSION: The Tasso+ accurately measures NfL and GFAP, but caution is warranted when measuring other AD/ADRD biomarkers, as agreement with venous plasma appears to be protein or ratio dependent. These results highlight that important biomarker-specific differences must be considered when translating capillary blood collection approaches. They also further support foundations for development of these methods, highlighting both the opportunities and remaining challenges for translating the promise of blood-based biomarkers beyond AD/ADRD specialty clinics and research settings.

Despite extensive knowledge of the progressive sequence of cognitive and functional deficits in Alzheimer's Disease (AD), the impact of neurodegeneration on the conscious experience of patients remains largely unexplored. Understanding how the content of consciousness, particularly perceptual awareness, changes with the progression of AD is crucial to enable meaningful person-centred care. This is especially important in severe AD when impairments in language and other cognitive domains mean people are unable to report their experiences. We investigated whether electrophysiological (EEG) and fMRI signatures of perceptual awareness described in healthy older people are present in people with mild-moderate and severe AD using two "no-report" paradigms. Firstly, a visual masking paradigm examined visual awareness negativity (VAN) and late positive (LP) electrophysiological responses and activation in visual cortex and fronto-parietal regions that are characteristically associated with conscious perception of faces; and second, a complex audio-visual (movie) task examined activation in fronto-parietal networks previously associated with perceptual awareness. In healthy older controls we found cortical responses characteristic of awareness in both EEG and fMRI modalities, with VAN and LP markers and widespread occipital, fusiform face area and fronto-parietal activation. In people with mild-moderate AD, there were significant reductions in VAN and LP markers and reduced fronto-parietal activation. In participants with severe AD, who were behaviourally minimally responsive, there was only limited evidence of presence of frontoparietal markers of perceptual awareness, however this may reflect attentional and task insensitivity in people with advanced dementia. These results demonstrate that the brain mechanisms associated with perceptual awareness become increasingly impaired with progression of AD. Specifically, involvement of frontoparietal networks is reduced in AD, which may reflect reduced higher-level awareness. This suggests AD should be considered a disorder of consciousness and should motivate further investigation into the dimensions of awareness affected by the disorder with implications for treatment and management of people with dementia.

Sleep disturbance in Alzheimer's disease (AD), particularly the reduction of slow wave sleep (SWS), has been proposed as a novel therapeutic target, with disease-modifying potential. Trazodone, an antidepressant with robust SWS-promoting properties, is currently the most prescribed sleep-promoting medication in the United States. Here, we demonstrate that chronic trazodone administration consolidates sleep in the APP NL-F knock-in mouse model of AD, increasing NREM sleep duration and slow wave power during the rest phase while promoting wake during the active phase. These sleep consolidating effects were accompanied by lower regional glial activation and amyloid burden, particularly in male mice. Most notably, hippocampal amyloid plaque burden was 45% lower in mice treated from 14 to 16 months of age than in vehicle-treated controls. Chronic trazodone treatment was also associated with better short-term and long-term recognition memory. Together, these findings support the potential of repurposing trazodone as a well-tolerated, disease-modifying therapeutic for AD, capable of enhancing sleep quality, improving cognition, and lowering AD-relevant neuropathology.