Alzheimer's & Dementia最新文献

Background: This study examines whether phosphorylated plasma Tau217 ratio (pTau217R) can predict tau accumulation in different brain regions, as measured by positron emission tomography (PET) standardized uptake value ratio (SUVR), for staging Alzheimer's disease (AD).

Methods: Plasma pTau217R was measured using immunoprecipitation-mass spectrometry. Models for predicting tau PET SUVR, developed with 144 early AD individuals using [¹⁸F]MK6240, were validated in two validation sets, VS1 (98 early AD) and VS2 (47 preclinical/early AD with a different tracer, flortaucipir (Tauvid)), all amyloid-beta positive (Aβ+).

Results: The pTau217R-based model predicted tau levels up to an SUVR of 2 in multiple brain regions, effectively assessing tau status at different tau levels with receiver operating characteristic (ROC) curve areas of 0.84-0.95 in VS1 and 0.71-0.88 in VS2 (using a different tracer). It reduced PET scan needs by 65% while maintaining 95% sensitivity.

Discussion: PTau217R reliably predicts regional tau accumulation in early AD, reducing reliance on tau PET scans and broadening its clinical application.

Clinical trial registration number: NCT03887455 (ClarityAD) HIGHLIGHTS: Developed a model using plasma pTau217R to predict tau levels across brain regions. pTau217R model outperformed models based on clinical, MRI, and other blood biomarkers. The model reliably predicted tau levels exceeding tau positivity and higher thresholds. Screening with pTau217R could reduce tau PET scans by 65% at 95% sensitivity. pTau217R model aids in disease staging and monitoring in early AD.

New possibilities of biomarker-based predictive technologies for Alzheimer's disease (AD) have become more reliable as well as more accessible. Standardized clinical recommendations and guidance for counseling and disclosure in this context are not yet well developed. Our scoping review identified publications from database searches in PubMed, PsycINFO, LIVIVO, and Web of Science. Inclusion criteria were: (1) information or counseling, (2) biomarkers and a type of cognitive impairment or AD, and (3) published between 2005 and 2024. We identified 63 articles and synthesized them along the categories of staged information provision: pre-test counseling, disclosure, and post-disclosure follow-up. Most publications referred to the context of disclosure (48), followed by pre-test counseling (33), and post-disclosure follow-up (31). Some publications referred to all stages of counseling (17). Our findings highlight the need to further develop and specify comprehensive and standardized guidelines for counseling, disclosure, and post-disclosure follow-up in the context of AD biomarker testing. HIGHLIGHTS: New possibilities of biomarker-based predictive technologies for Alzheimer's disease (AD) have become more reliable and also more accessible. However, clinical recommendations and guidance for counseling and disclosure in the context of AD biomarker testing are currently not well developed. We carried out a scoping review with the aim to generate an overview of the scientific literature and guidance available regarding counseling, biomarker test result and dementia risk disclosure, and clinical management prior to and in the course of a biomarker-based diagnosis in early stages of AD. We identified 63 relevant articles. Most publications referred to the context of disclosure (48), followed by pre-test counseling (33), and post-disclosure follow-up (31). Some publications referred to all stages of counseling (17). Our findings highlight the urgent need for national and international consensus guidelines for comprehensive and staged counseling and disclosure practices. While most publications identify relevant ethical challenges posed for counseling practices in the context of AD biomarker testing, they rarely present any practical recommendations for clinicians, on how and what to counsel on a concrete level.

Background: Associations between longitudinal changes of plasma biomarkers and cerebral magnetic resonance (MR)-derived measurements in Alzheimer's disease (AD) remain unclear.

Methods: In a study population (n = 127) of healthy older adults and patients within the AD continuum, we examined associations between longitudinal plasma amyloid beta 42/40 ratio, tau phosphorylated at threonine 181 (p-tau181), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and 7T structural and functional MR imaging and spectroscopy using linear mixed models.

Results: Increases in both p-tau181 and GFAP showed the strongest associations to 7T MR-derived measurements, particularly with decreasing parietal cortical thickness, decreasing connectivity of the salience network, and increasing neuroinflammation as determined by MR spectroscopy (MRS) myo-inositol.

Discussion: Both plasma p-tau181 and GFAP appear to reflect disease progression, as indicated by 7T MR-derived brain changes which are not limited to areas known to be affected by tau pathology and neuroinflammation measured by MRS myo-inositol, respectively.

Highlights: This study leverages high-resolution 7T magnetic resonance (MR) imaging and MR spectroscopy (MRS) for Alzheimer's disease (AD) plasma biomarker insights. Tau phosphorylated at threonine 181 (p-tau181) and glial fibrillary acidic protein (GFAP) showed the largest changes over time, particularly in the AD group. p-tau181 and GFAP are robust in reflecting 7T MR-based changes in AD. The strongest associations were for frontal/parietal MR changes and MRS neuroinflammation.

Introduction: Though recognized as a potential cause of autosomal dominant Alzheimer's disease, the pathogenicity of many PSEN2 variants remains uncertain. We compared amyloid beta (Aβ) production across all missense PSEN2 variants in the AlzForum database and, when possible, to corresponding PSEN1 variants.

Methods: We expressed 74 PSEN2 variants, 21 of which had known, homologous PSEN1 pathogenic variants with the same amino acid substitution, in HEK293 cells lacking presenilin 1/2. Aβ production was compared to age at symptom onset (AAO) and between PSEN1/2 homologs.

Results: Aβ42/40 and Aβ37/42 ratios correlated with AAO across all PSEN2 variants, strongly driven by the subset of PSEN2 variants with PSEN1 homologs. Aβ production across PSEN1/2 homologs was highly correlated. PSEN2 AAO correlated with AAO in PSEN1 homologs but was an average of 18.3 years later.

Discussion: The existence of a PSEN1 homolog and patterns of Aβ production are important considerations in assessing the pathogenicity of previously reported and new PSEN2 variants.

Highlights: There were associations between the patterns of amyloid beta (Aβ) production across presenilin 2 (PSEN2) variants and age at symptom onset (AAO). PSEN2 variants for which there is a known, corresponding variant in presenilin 1 (PSEN1) are more likely to have abnormal Aβ production patterns that strongly correlate with AAO, compared to those that lack a known PSEN1 counterpart ("non-homologous PSEN2 variants"). Most PSEN2 variants lacking PSEN1 counterparts had Aβ42/40 ratios close to those of wild-type PSN2, arguing against their pathogenicity. Homologous PSEN1 and PSEN2 variants had correlated Aβ42/40 and Aβ37/42 ratios, indicating that the corresponding amino acid substitution in each presenilin may have largely similar biochemical effects on γ-secretase processivity.

Introduction: It remains unclear whether the local amyloid-beta (Aβ) burden in key regions within the default mode network (DMN) affects network and cognitive functions.

Methods: Participants included 1002 individuals from the Chinese Preclinical Alzheimer's Disease Study cohort who underwent 18F-florbetapir positron emission tomography resting-state functional magnetic resonance imaging scanning and neuropsychological tests. The correlations between precuneus (PRC) Aβ burden, DMN function, and cognitive function were investigated.

Results: In individuals with high PRC Aβ burden, there is a bidirectional relationship between DMN local function or functional connectivity and PRC Aβ deposition across various cognitive states, which is also linked to cognitive function. Even below the PRC Aβ threshold, DMN function remains related to PRC Aβ deposition and cognitive performance.

Discussion: The findings reveal the critical role of PRC Aβ deposition in disrupting neural networks associated with cognitive decline and the necessity of early detection and monitoring of PRC Aβ deposition.

Highlights: Precuneus (PRC) Aβ burden impacts DMN function in different cognitive stages. High PRC Aβ burden is linked to early neural compensation and subsequent dysfunction. Low PRC Aβ burden correlates with neural changes before significant Aβ accumulation. Changes in DMN function and connectivity provide insights into AD progression. Early detection of regional Aβ burden can help monitor the risk of cognitive decline.

Introduction: Collaborative dementia care models with care navigation, including the Care Ecosystem, improve outcomes for persons living with dementia (PLWDs) and their caregivers. The effects of continuous care over long periods have not been studied.

Methods: In this randomized clinical trial with 456 PLWD-caregiver dyads with high caregiver burden, we evaluated the cumulative 5-year treatment effect on PLWD quality of life, health care utilization, caregiver depression, self-efficacy, and burden.

Results: Five-year participation was associated with higher quality of life, lower caregiver depression, and higher caregiver self-efficacy (all p's < 0.05) with a trend for lower burden (p = 0.07). Treatment effects were most robust during the first 2 years. The effects on emergency department visits and hospitalizations were not significant.

Discussion: The benefits of collaborative dementia care on PLWD quality of life and caregiver well-being are sustained for 5 years, and the dyads may experience the greatest benefit during the first 2 years.

Highlights: Collaborative dementia care with care navigation was evaluated over 5 years using a randomized clinical trial. The care was associated with better quality of life for the person with dementia and well-being for the caregiver. The most robust treatment effects were in the first 2 years.

Background: The history from a relative or caregiver is an important tool for differentiating neurodegenerative disease. We characterized patterns of caregiver questionnaire responses, at diagnosis and follow-up, on the Cambridge Behavioural Inventory (CBI).

Methods: Data-driven multivariate analysis (n = 4952 questionnaires) was undertaken for participants (n = 2481) with Alzheimer's disease (typical/amnestic n = 543, language n = 50, and posterior cortical n = 50 presentations), Parkinson's disease (n = 740), dementia with Lewy bodies (n = 55), multiple system atrophy (n = 55), progressive supranuclear palsy (n = 422), corticobasal syndrome (n = 176), behavioral variant frontotemporal dementia (n = 218), semantic (n = 125) and non-fluent variant progressive aphasia (n = 88), and motor neuron disease (n = 12).

Results: Item-level support vector machine learning gave high diagnostic accuracy between diseases (area under the curve mean 0.83), despite transdiagnostic changes in memory, behavior, and everyday function. There was progression in CBI subscores over time, which varied by diagnosis.

Discussion: Our results highlight the differential diagnostic information for a wide range of neurodegenerative diseases contained in a simple, structured collateral history.

Highlights: We analyzed 4952 questionnaires from caregivers of 2481 participants with neurodegenerative disease. Behavioral and neuropsychiatric manifestations of neurodegenerative disease had overlapping diagnostic boundaries. Simple questionnaire response patterns were sufficient for accurate diagnosis of each disease. We reinforce the value of a collateral history to support a diagnosis of dementia. The Cambridge Behavioural Inventory is sensitive to change over time and suitable as an outcome measure in clinical trials.