The latest medical research on Alzheimers

The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about alzheimers gathered by our medical AI research bot.

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The power of representation: Statistical analysis of diversity in US Alzheimer's disease genetics data.

Alzheimers Dement (N

Alzheimer's disease (AD) is a complex disease influenced by genetics and environment. More than 75 susceptibility loci have been linked to late-onset AD, but most of these loci were discovered in genome-wide association studies (GWAS) exclusive to non-Hispanic White individuals. There are wide disparities in AD risk across racially stratified groups, and while these disparities are not due to genetic differences, underrepresentation in genetic research can further exacerbate and contribute to their persistence. We investigated the racial/ethnic representation of participants in United States (US)-based AD genetics and the statistical implications of current representation.

We compared racial/ethnic data of participants from array and sequencing studies in US AD genetics databases, including National Institute on Aging Genetics of Alzheimer's Disease Data Storage Site (NIAGADS) and NIAGADS Data Sharing Service (dssNIAGADS), to AD and related dementia (ADRD) prevalence and mortality. We then simulated the statistical power of these datasets to identify risk variants from non-White populations.

There is insufficient statistical power (probability <80%) to detect single nucleotide polymorphisms (SNPs) with low to moderate effect sizes (odds ratio [OR]<1.5) using array data from Black and Hispanic participants; studies of Asian participants are not powered to detect variants OR <= 2. Using available and projected sequencing data from Black and Hispanic participants, risk variants with OR = 1.2 are detectable at high allele frequencies. Sample sizes remain insufficiently powered to detect these variants in Asian populations.

AD genetics datasets are largely representative of US ADRD burden. However, there is a wide discrepancy between proportional representation and statistically meaningful representation. Most variation identified in GWAS of non-Hispanic White individuals have low to moderate effects. Comparable risk variants in non-White populations are not detectable given current sample sizes, which could lead to disparities in future studies and drug development. We urge AD genetics researchers and institutions to continue investing in recruiting diverse participants and use community-based participatory research practices.

Glymphatic system dysfunction predicts amyloid deposition, neurodegeneration, and clinical progression in Alzheimer's disease.

Alzheimers & Dementia

Although glymphatic function is involved in Alzheimer's disease (AD), its potential for predicting the pathological and clinical progression of AD and its sequential association with core AD biomarkers is poorly understood.

Whole-brain glymphatic activity was measured by diffusion tensor image analysis along the perivascular space (DTI-ALPS) in participants with AD dementia (n = 47), mild cognitive impairment (MCI; n = 137), and normal controls (n = 235) from the Alzheimer's Disease Neuroimaging Initiative.

ALPS index was significantly lower in AD dementia than in MCI or controls. Lower ALPS index was significantly associated with faster changes in amyloid positron emission tomography (PET) burden and AD signature region of interest volume, higher risk of amyloid-positive transition and clinical progression, and faster rates of amyloid- and neurodegeneration-related cognitive decline. Furthermore, the associations of the ALPS index with cognitive decline were fully mediated by amyloid PET and brain atrophy.

The analysis along the perivascular space (ALPS) index is reduced in patients with Alzheimer's disease (AD) dementia, prodromal AD, and preclinical AD. Lower ALPS index predicted accelerated amyloid beta (Aβ) positron emission tomography (PET) burden and Aβ-positive transition. The decrease in the ALPS index occurs before cerebrospinal fluid Aβ42 reaches the positive threshold. ALPS index predicted brain atrophy, clinical progression, and cognitive decline. Aβ PET and brain atrophy mediated the link of ALPS index with cognitive decline.

Viscous dynamics associated with hypoexcitation and structural disintegration in neurodegeneration via generative whole-brain modeling.

Alzheimers & Dementia

Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) lack mechanistic biophysical modeling in diverse, underrepresented populations. Electroencephalography (EEG) is a high temporal resolution, cost-effective technique for studying dementia globally, but lacks mechanistic models and produces non-replicable results.

We developed a generative whole-brain model that combines EEG source-level metaconnectivity, anatomical priors, and a perturbational approach. This model was applied to Global South participants (AD, bvFTD, and healthy controls).

Metaconnectivity outperformed pairwise connectivity and revealed more viscous dynamics in patients, with altered metaconnectivity patterns associated with multimodal disease presentation. The biophysical model showed that connectome disintegration and hypoexcitability triggered altered metaconnectivity dynamics and identified critical regions for brain stimulation. We replicated the main results in a second subset of participants for validation with unharmonized, heterogeneous recording settings.

The results provide a novel agenda for developing mechanistic model-inspired characterization and therapies in clinical, translational, and computational neuroscience settings.

Delineating cognitive resilience using fractal regulation: Cross-sectional and longitudinal evidence from the Rush Memory and Aging Project.

Alzheimers & Dementia

Degradation of fractal patterns in actigraphy independently predicts dementia risk. Such observations motivated the study to understand the role of fractal regulation in the context of neuropathologies.

We examined associations of fractal regulation with neuropathologies and longitudinal cognitive changes in 533 older participants who were followed annually with actigraphy and cognitive assessments until death with brain autopsy performed. Two measures for fractal patterns were extracted from actigraphy, namely, α1 (representing the fractal regulation at time scales of <90 min) and α2 (for time scales 2 to 10 h).

We found that larger α1 was associated with lower burdens of Lewy body disease or cerebrovascular disease pathologies; both α1 and α2 were associated with cognitive decline. They explained an additional significant portion of the variance in the rate of cognitive decline above and beyond neuropathologies.

Fractal patterns may be used as a biomarker for cognitive resilience against dementia-related neuropathologies.

Association between hippocampal microglia, AD and LATE-NC, and cognitive decline in older adults.

Alzheimers & Dementia

This study investigates the relationship between microglia inflammation in the hippocampus, brain pathologies, and cognitive decline.

Participants underwent annual clinical evaluations and agreed to brain donation. Neuropathologic evaluations quantified microglial burden in the hippocampus, amyloid beta (Aβ), tau tangles, and limbic age-related transactive response DNA-binding protein 43 (TDP-43) encephalopathy neuropathologic changes (LATE-NC), and other common brain pathologies. Mixed-effect and linear regression models examined the association of microglia with a decline in global and domain-specific cognitive measures, and separately with brain pathologies. Path analyses estimated direct and indirect effects of microglia on global cognition.

Hippocampal microglia were associated with a faster decline in global cognition, specifically in episodic memory, semantic memory, and perceptual speed. Tau tangles and LATE-NC were independently associated with microglia. Other pathologies, including Aβ, were not related. Regional hippocampal burden of tau tangles and TDP-43 accounted for half of the association of microglia with cognitive decline.

Microglia inflammation in the hippocampus contributes to cognitive decline. Tau tangles and LATE-NC partially mediate this association.

Dementia and mild cognitive impairment screening in an emergency homeless shelter.

Alzheimers & Dementia

Older adults represent the fastest growing segment of the homeless community. Little is known about the prevalence of dementia and mild cognitive impairment (MCI) in this population.

Dementia and MCI screening using the Montreal Cognitive Assessment (MoCA) was incorporated into the standard senior evaluation for adult clients aged ≥ 55 in a large emergency homeless shelter.

In a 6-week period, 104 of 112 (92.9%) assessments were positive for dementia or MCI using a standard cutoff of 26, and 81 (72.3%) were positive using a conservative cutoff of 23. There was no significant difference in MoCA scores based on sex or education level, and no significant correlation between age and MoCA score.

Older adults experiencing homelessness may have a high likelihood of dementia or MCI. Routine MoCA screening in older adults experiencing homelessness is feasible and can help to identify services needed to successfully exit homelessness.

Wrist-worn actigraphy in agitated late-stage dementia patients: A feasibility study on digital inclusion.

Alzheimers & Dementia

Wrist-worn actigraphy can be an objective tool to assess sleep and other behavioral and psychological symptoms in dementia (BPSD). We investigated the feasibility of using wearable actigraphy in agitated late-stage dementia patients.

Agitated, late-stage Alzheimer's dementia care home residents in Greater London area (n = 29; 14 females, mean age ± SD: 80.8 ± 8.2; 93.1% White) were recruited to wear an actigraphy watch for 4 weeks. Wearing time was extracted to evaluate compliance, and factors influencing compliance were explored.

A high watch-acceptance (96.6%) and compliance rate (88.0%) was noted. Non-compliance was not associated with age or BPSD symptomatology. However, participants with "better" cognitive function (R = 0.42, p = 0.022) and during nightshift (F1.240, 33.475  = 8.075, p = 0.005) were less compliant. Female participants were also marginally less compliant (F1, 26  = 3.790, p = 0.062).

Wrist-worn actigraphy appears acceptable and feasible in late-stage agitated dementia patients. Accommodating the needs of both the patients and their carers may further improve compliance.

Deriving life-course residential histories in brain bank cohorts: A feasibility study.

Alzheimers & Dementia

The exposome is theorized to interact with biological mechanisms to influence risk for Alzheimer's disease but is not well-integrated into existing Alzheimer's Disease Research Center (ADRC) brain bank data collection.

We apply public data tracing, an iterative, dual abstraction and validation process rooted in rigorous historic archival methods, to develop life-course residential histories for 1254 ADRC decedents.

The median percentage of the life course with an address is 78.1% (IQR 24.9); 56.5% of the sample has an address for at least 75% of their life course. Archivists had 89.7% agreement at the address level. This method matched current residential survey methodology 97.4% on average.

Public data tracing compares favorably to survey-based residential history. Public data tracing is feasible and reproducible between archivists. Archivists achieved 89.7% agreement at the address level. This method identifies residences for nearly 80% of life-years, on average. This novel method enables brain banks to add social characterizations.

Commentary: Can an effective end-of-life intervention for advanced dementia be viewed as moral?

Alzheimers Dementia Amsterdam

We comment on Dr. Terman's considerations on the moral justification of ceasing assisted feeding and hydration for people with advanced dementia. T...

Timely dying in dementia: Use patients' judgments and broaden the concept of suffering.

Alzheimers Dementia Amsterdam

Patients living with advanced dementia (PLADs) face several challenges to attain the goal of avoiding prolonged dying with severe suffering. One is...

Navigating late-stage dementia: A perspective from the Alzheimer's Association.

Alzheimers Dementia Amsterdam

Alzheimer's disease (AD) is the most common cause of dementia, a general term for memory loss and decline in other cognitive abilities enough to in...

Fasting to stop suffering in advanced dementia.

Alzheimers Dementia Amsterdam

Many healthcare providers think withholding food and fluids from advance dementia patients, even if those patients requested that when competent, i...