Screening for dysphagia in older people with dementia: Evidence of validity based on internal structure and reliability of the Caregiver Questionnaire - RaDID-QC.

OBJECTIVE: To identify internal structure validity evidence of a dysphagia screening questionnaire for caregivers of older adults with Alzheimer's disease dementia and/or vascular dementia. METHODS: The 24-question Dysphagia Screening in Older Adults with Dementia - Caregiver Questionnaire (RaDID-QC) was administered by interviewing 170 caregivers of older people with dementia, selected by convenience at the Outpatient Reference Center for Older People. Exploratory Factor Analysis (EFA) was used to assess the internal structure validity of the questionnaire, and Cronbach's alpha was used to analyze reliability. Questions with factor loadings lower than 0.45 in magnitude were removed from the final questionnaire. Multivariate multiple linear regression was used to assess the percentage of variance explained by the remaining questions. RESULTS: Kayser-Meyer-Olkin (KMO) and Bartlett's tests suggested that the questionnaire was adequate for EFA. Principal Component Analysis (PCA) suggested that 12 components captured at least 75 % of the total variance. The corresponding 12-factor EFA model showed a statistically significant fit, and 15 out of the 24 questions had factor loadings greater than 0.45. Cronbach's alpha was 0.74 for the 15 questions, which explained 71 % of the total variance in the complete dataset. The questionnaire has adequate internal structure validity and good reliability. Based on EFA, RaDID-QC decreased from 24 to 15 questions. Other internal validity and reliability parameters will be obtained by administering the questionnaire to larger target populations. CONCLUSION: The RaDID-QC applied to caregivers of older adults with dementia due to Alzheimer's disease and/or vascular dementia produced valid and reliable responses to screen dysphagia signs and symptoms.

Association between cognitive impairment and socioeconomic and sociodemographic factors in Colombian older adults.

INTRODUCTION: Worldwide, because of the demographic transition, the proportion of older adults has increased, which has been reflected in an increase in the prevalence of major neurocognitive disorder (MND). This phenomenon is especially important in low- and middle-income countries such as Colombia, given the high economic and social costs it entails. The objective was to analyse the association between socioeconomic variables with the presence of cognitive impairment in Colombian older adults. METHODS: The records of 23,694 adults over 60 years-of-age surveyed for SABE Colombia 2015, that took a stratified sample by conglomerates and were representative of the adult population over 60 years-of-age. This instrument assessed cognitive impairment using the abbreviated version of the Minimental (AMMSE) and collected information on multiple socioeconomic variables. RESULTS: 19.7% of the older adults included in the survey were reviewed with cognitive impairment by presenting a score <13 in the AMMSE. There was a higher prevalence of cognitive impairment in women (21.5%) than in men (17.5%). The socioeconomic variables were shown to impact the prevalence of deterioration, especially being currently working (OR = 2.74; 95%CI, 2.43-3.09) as a risk factor and having attended primary school as a protective factor (OR = 0.30; 95%CI, 0.28-0.32), differentially according to gender. CONCLUSIONS: An association between socioeconomic and sociodemographic factors with cognitive impairment in Colombian older adults was evidenced. Despite the above, a differential impact dependent on sex is suggested.

Central and peripheral mechanisms underlying respiratory deficits in a mouse model of accelerated senescence.

Aging invariably decreases sensory and motor stimuli and affects several neuronal systems and their connectivity to key brain regions, including those involved in breathing. Nevertheless, further investigation is needed to fully comprehend the link between senescence and respiratory function. Here, we investigate whether a mouse model of accelerated senescence could develop central and peripheral respiratory abnormalities. Adult male Senescence Accelerated Mouse Prone 8 (SAMP8) and the control SAMR1 mice (10 months old) were used. Ventilatory parameters were assessed by whole-body plethysmography, and measurements of respiratory input impedance were performed. SAMP8 mice exhibited a reduction in the density of neurokinin-1 receptor immunoreactivity in the entire ventral respiratory column. Physiological experiments showed that SAMP8 mice exhibited a decreased tachypneic response to hypoxia (FiO2 = 0.08; 10 min) or hypercapnia (FiCO2 = 0.07; 10 min). Additionally, the ventilatory response to hypercapnia increased further due to higher tidal volume. Measurements of respiratory mechanics in SAMP8 mice showed decreased static compliance (Cstat), inspiratory capacity (IC), resistance (Rn), and elastance (H) at different ages (3, 6, and 10 months old). SAMP8 mice also have a decrease in contractile response to methacholine compared to SAMR1. In conclusion, our findings indicate that SAMP8 mice display a loss of the NK1-expressing neurons in the respiratory brainstem centers, along with impairments in both central and peripheral respiratory mechanisms. These observations suggest a potential impact on breathing in a senescence animal model.

Clinical Characteristics of Older Adults Living in Foster Families in the French West Indies: Baseline Screening of the KArukera Study of Aging in Foster Families (KASAF) Cohort.

Background and Objectives: Foster families for older adults could represent a transitional or alternative model to nursing homes. The aim of this study was to describe the clinical characteristics of older adults in foster families and to compare them with those of residents in nursing homes in French West Indies. Research Design and Methods: This study is a cross-sectional analysis of the KArukera Study of Aging in Foster Families (KASAF) cohort. Sociodemographic and clinical characteristics were extracted. Dependency was assessed using the Activities of Daily Living (ADL) scale and cognition using the Mini-Mental State Examination (MMSE) scale. Age, gender, ADL, and MMSE scores were compared with nursing home residents from a twin study of KASAF (n = 332). Results: A total of 107 older adults (mean age 81.8 years; 61.7% women) were recruited in 56 foster families between September 2020 and May 2021. In all, 25.5% had diabetes mellitus and 45.8% suffered from hypertension. The mean MMSE score was 9.3 ± 10.1 and 76.0% had major cognitive impairment (MMSE score <18); 12.5% were diagnosed with Parkinson's disease, and 42.0% of the residents were confined to bed or in a wheelchair, with a mean ADL score of 1.5 ± 1.8. Almost all the residents (96.3%) benefited from a medical follow-up by a nurse who visited once or twice a day. Compared to older adults living in nursing homes, those in foster families were more frequently women (61.7% vs 49.4%) and had lower ADL score (1.5 vs 2.4) and lower MMSE score (9.3 vs 11.3). Discussion and Implications: The clinical profile of foster families' residents was quite similar to that of nursing home residents in terms of demographics, dementia, and dependency. Foster families might represent an interesting strategy to address the unmet clinical and social needs of dependent older adults, especially in countries where nursing homes are not sufficiently developed. Clinical Trials Registration Number: NCT04545775.

Feeding and Nutrition for People with Dementia in Gerontological Services: A Focus Group Study.

Purpose: This work sought to describe the experience of managers and caregivers with feeding and nutrition for older adults with dementia, in Colombian gerontological services. Participants and Methods: This is a qualitative focus group study with fourteen gerontological care centers for people with dementia. Results: The study reveals that care related to food and nutrition for people with dementia is organized based on the comprehensive assessment of the resident. Although there are basic support strategies, each caregiver requires specific knowledge, attitudes, behaviors, and institutional support, to generate a context that favors the health and quality of life of those involved. Conclusion: The experience of caring for people with dementia in aspects related to their food and nutrition, seen from the perspective of managers and caregivers of gerontological services in a developing country, strengthens specific strategies and public policies. This, in turn, reduces the burden on caregivers.

Educational disparities in brain health and dementia across Latin America and the United States.

BACKGROUND: Education influences brain health and dementia. However, its impact across regions, specifically Latin America (LA) and the United States (US), is unknown. METHODS: A total of 1412 participants comprising controls, patients with Alzheimer's disease (AD), and frontotemporal lobar degeneration (FTLD) from LA and the US were included. We studied the association of education with brain volume and functional connectivity while controlling for imaging quality and variability, age, sex, total intracranial volume (TIV), and recording type. RESULTS: Education influenced brain measures, explaining 24%-98% of the geographical differences. The educational disparities between LA and the US were associated with gray matter volume and connectivity variations, especially in LA and AD patients. Education emerged as a critical factor in classifying aging and dementia across regions. DISCUSSION: The results underscore the impact of education on brain structure and function in LA, highlighting the importance of incorporating educational factors into diagnosing, care, and prevention, and emphasizing the need for global diversity in research. HIGHLIGHTS: Lower education was linked to reduced brain volume and connectivity in healthy controls (HCs), Alzheimer's disease (AD), and frontotemporal lobar degeneration (FTLD). Latin American cohorts have lower educational levels compared to the those in the United States. Educational disparities majorly drive brain health differences between regions. Educational differences were significant in both conditions, but more in AD than FTLD. Education stands as a critical factor in classifying aging and dementia across regions.

Effectiveness of Internet-Based or Mobile App Interventions for Family Caregivers of Older Adults with Dementia: A Systematic Review.

INTRODUCTION: Global aging presents socioeconomic and health challenges. Dementia, a growing concern, affects millions of older adults, intensifying the burden on family caregivers. E-health interventions offer hope through technological solutions, although current research is limited. This study evaluated the effectiveness of internet-based or mobile app interventions for family caregivers of older adults with dementia. METHODOLOGY: A systematic review with a narrative synthesis was conducted using databases (PubMed, CINAHL, Scopus, LILACS, and PsycInfo) and the bibliographies of retrieved articles, with no restrictions on time or language. RESULTS: The search yielded 2092 results, of which 22 studies met the inclusion criteria, encompassing a total of 2761 family caregivers. Twenty-one different outcomes were evaluated and classified into three main types of interventions: psychoeducational, psychotherapeutic, and multicomponent. CONCLUSIONS: The study highlights the importance of internet-based and mobile app interventions in supporting family caregivers of older adults with dementia. These interventions positively affect many aspects of caregiver well-being, suggesting their utility in addressing this group's emotional, social, and self-care needs.

Episodic memory improvement in illiterate adults attending late-life education irrespective of low socioeconomic status: insights from the PROAME study.

The majority of people with dementia live in low or middle-income countries (LMICs) where resources that play a crucial role in brain health, such as quality education, are still not widely available. In Brazil, illiteracy remains a prevalent issue, especially in communities with lower socioeconomic status (SES). The PROAME study set out to explore basic education in illiterate adults as a means to improve cognitive reserve. Objective: This manuscript aims to explore the relationship between SES and learning, as well as cognitive outcomes, in an older illiterate population. Methods: This six-month clinical trial (NCT04473235) involved 108 participants, of which 77 concluded all assessments, enrolled in late-life basic education. SES assessments included Quality of Urban Living Index, Municipal Human Development Index and Household SES calculated for each participant. Cognitive assessments encompassed the Free and Cued Selective Reminding Test (FCSRT), a word list to assess reading, and the Beta III matrix. Results: The sample consisted primarily of women, with a mean age of 58.5. Participants improved their reading (p=0.01) and their FCSRT (p=0.003). Regarding episodic memory, women outperformed men (p=0.007) and younger participants improved more than their older counterparts (p=0.001). There was no association observed between SES and cognitive outcomes. Conclusion: Irrespective of SES, participants demonstrated positive outcomes after attending basic education. These findings highlight that late life education could be an important non-pharmacologic preventative measure, especially in LMICs.

A maioria das pessoas com demência vive em países de baixa/média renda, onde recursos essenciais para a saúde cerebral, como educação de qualidade, ainda não são amplamente acessíveis. No Brasil, o analfabetismo ainda é frequente, especialmente em comunidades de baixo nível socioeconômico. O estudo PROAME teve como objetivo explorar a educação básica tardia em pessoas analfabetas como ferramenta para o aumento da reserva cognitiva. Objetivo: Investigar a relação entre nível socioeconômico com aprendizado e com desempenho em testes cognitivos, em adultos analfabetos. Métodos: Este estudo clínico de seis meses (NCT04473235) contou com 108 participantes inscritos no projeto Educação para Jovens e Adultos (EJA), dos quais 77 completaram os testes. O nível socioeconômico de cada participante foi medido usando-se: o Índice de Qualidade de Vida Urbana, o Índice de Desenvolvimento Humano Municipal e o nível socioeconômico doméstico. Avaliações cognitivas incluíram: o Teste de Recordação Seletiva Livre e Guiada (TRSLG), uma lista de palavras para avaliar leitura e a matriz Beta III. Resultados: A amostra era predominantemente feminina, com idade média de 58,5. Os participantes melhoraram a leitura (p=0,01) e o TRSLG (p=0,003). Com relação à memoria episódica, as mulheres tiveram resultados superiores aos dos homens (p=0,007) e participantes mais jovens melhoraram mais que seus colegas mais velhos (p=0,001). Não foi observada nenhuma relação entre o nível socioeconômico e o desempenho cognitivo. Conclusão: Independentemente do nível socioeconômico, participantes obtiveram resultados positivos após frequentar a educação básica. Isso sugere que a educação tardia pode ser uma medida preventiva não farmacológica importante, especialmente em países de baixa/média renda.

Effects of Hearing Aid Use on Individuals Diagnosed with Hearing Loss and Dementia: A Systematic Review.

Background: The assumption that hearing rehabilitation could improve quality of life and reduce dementia risk in people with hearing loss is a subject that needs further studies, especially clinical trials. It is necessary to determine the effects of hearing aid use, as part of hearing rehabilitation, among people diagnosed with dementia. Objective: To systematically review the literature to evaluate the effects of hearing aid use on cognition and quality of life of people with dementia. Methods: Protocol for this systematic review was registered (CRD42023387187). The Cochrane Central Register of Controlled Trials, Embase, MEDLINE, Scopus, CINAHL, and Web of Science databases, as well as grey literature, including Google Scholar and ResearchGate, were systematically searched for clinical trials using MeSH terms. The PICOS principle was used to develop the inclusion criteria: population (P): adults and older adults, individuals diagnosed with dementia and hearing loss; intervention (I): rehabilitation with hearing aids; control (C): not using a hearing aid; outcome (O): cognitive and/or quality of life assessment using validated tests; study design (S): clinical trial. Results: The initial search yielded 576 studies, five of which met the inclusion criteria for qualitative analyses. Two of the included studies were randomized clinical trials, and three were crossover clinical trials, demonstrating the lack of studies on the subject. Four studies included participants with Alzheimer's disease. Quality of life was found to improve with the use of hearing aids, and hearing rehabilitation was not shown to affect cognitive outcomes. Conclusions: Hearing aid use appears to have a positive impact on quality of life.

Improved Accuracy of the Addenbrooke's Cognitive Examination-Revised in the Diagnosis of Mild Cognitive Impairment, Mild Dementia Due to Alzheimer's Disease and Behavioral Variant Frontotemporal Dementia Using Mokken Scale Analysis.

Background: The Addenbrooke's Cognitive Examination-Revised (ACE-R) is an accessible cognitive tool that supports the early detection of mild cognitive impairment (MCI), Alzheimer's disease (AD), and behavioral variant frontotemporal dementia (bvFTD). Objective: To investigate the diagnostic efficacy of the ACE-R in MCI, AD, and bvFTD through the identification of novel coefficients for differentiation between these diseases. Methods: We assessed 387 individuals: 102 mild AD, 37 mild bvFTD, 87 with amnestic MCI patients, and 161 cognitively unimpaired controls. The Mokken scaling technique facilitated the extraction out of the 26 ACE-R items that exhibited a common latent trait, thereby generating the Mokken scales for the AD group and the MCI group. Subsequently, we performed logistic regression, integrating each Mokken scales with sociodemographic factors, to differentiate between AD and bvFTD, as well as between AD or MCI and control groups. Ultimately, the Receiver Operating Characteristic curve analysis was employed to assess the efficacy of the coefficient's discrimination. Results: The AD-specific Mokken scale (AD-MokACE-R) versus bvFTD exhibited an Area Under the Curve (AUC) of 0.922 (88% sensitivity and specificity). The AD-MokACE-R versus controls achieved an AUC of 0.968 (93% sensitivity, 94% specificity). The MCI-specific scale (MCI-MokACE-R) versus controls demonstrated an AUC of 0.859 (78% sensitivity, 79% specificity). Conclusions: The ACE-R's capacity is enhanced through statistical methods and demographic integration, allowing for accurate differentiation between AD and bvFTD, as well as between MCI and controls. This new method not only reinforces its clinical value in early diagnosis but also surpasses traditional approaches noted in prior studies.

Socioeconomic determinants of cognition among older adults in the Brazilian longitudinal study of aging (ELSI-Brazil): a life-course approach.

BACKGROUND: The prevalence of cognitive impairment no dementia (CIND) and dementia appears to be higher in low- and middle-income countries (LMICs) compared to high-income economies. Yet few nationally representative studies from Latin American LMICs have investigated life-course socioeconomic factors associated with the susceptibility to these two cognitive conditions. Hence, the present study aimed to examine the associations of early- (education and food insecurity), mid- (employment stability), and late-life (personal income and household per capita income) socioeconomic determinants of CIND and dementia among older adults from Brazil, while simultaneously exploring whether sex plays an effect-modifier role on these associations. METHODS: This population-based study comprised a nationally representative sample of older adults (N = 5,249) aged 60 years and over from the Brazilian Longitudinal Study of Aging (ELSI-Brazil). We fitted multinomial regressions and estimated odds ratios with the respective 95% confidence intervals (CIs). RESULTS: In multivariate analyses, participants with more years of early-life education (0.89, 95% CI [0.81, 0.97]) and mid-life employment stability (0.97, 95% CI [0.96, 0.99]) and higher late-life household per capita income (0.70, 95% CI [0.51, 0.95) were less likely to have dementia. Regarding CIND, more years of mid-life employment stability (0.97, 95% CI [0.96, 0.98]) was the only determinant to confer protection. Notably, secondary sex-based analyses showed the higher the early-life educational attainment, the lower the odds of dementia in women (0.81, 95% CI [0.75, 0.87]) but not in men (1.00, 95% CI [0.86, 1.16]). CONCLUSIONS: These findings may have implications for population health and health policy by advancing our understanding of socioeconomic determinants of CIND and dementia, especially in Latin America.

Allostatic Interoceptive Overload Across Psychiatric and Neurological Conditions.

Emerging theories emphasize the crucial role of allostasis (anticipatory and adaptive regulation of the body's biological processes) and interoception (integration, anticipation, and regulation of internal bodily states) in adjusting physiological responses to environmental and bodily demands. In this review, we explore the disruptions in integrated allostatic interoceptive mechanisms in psychiatric and neurological disorders, including anxiety, depression, Alzheimer's disease, and frontotemporal dementia. We assess the biological mechanisms associated with allostatic interoception, including whole-body cascades, brain structure and function of the allostatic interoceptive network, heart-brain interactions, respiratory-brain interactions, the gut-brain-microbiota axis, peripheral biological processes (inflammatory, immune), and epigenetic pathways. These processes span psychiatric and neurological conditions and call for developing dimensional and transnosological frameworks. We synthesize new pathways to understand how allostatic interoceptive processes modulate interactions between environmental demands and biological functions in brain disorders. We discuss current limitations of the framework and future transdisciplinary developments. This review opens a new research agenda for understanding how allostatic interoception involves brain predictive coding in psychiatry and neurology, allowing for better clinical application and the development of new therapeutic interventions.

Physical Exercise Inhibits Cognitive Impairment and Memory Loss in Aged Mice, and Enhances Pre- and Post-Synaptic Proteins in the Hippocampus of Young and Aged Mice.

The aim of this study was to evaluate the effects of swimming in the brain and behavior of young and aged mice. Forty-eight male C57BL/6 J mice were randomly distributed into 4 groups (n = 12 per group, 3 and 18 months old). The subdivision of the groups was: 3 months-SED, 18 months-SED, 3 months-EXE, and 18 months-EXE. SED mice did not swim, while EXE mice performed the physical exercise protocol. Training was initiated 48 h after the adaptation week. Swimming sessions consisted of 30 min, with no overload, 5 days per week, for 4 weeks. After the exercise protocol, it was revealed working and spatial memory were impaired in the 18 months-SED group. Pre- and post-synaptic proteins were enhanced in the groups that swam when compared to the 3- and 8 months-SED groups. Lipid peroxidation was greater in the aged mice that did not perform the physical exercise protocol and might have contributed to the cognitive impairment in this group. In conclusion, an aerobic physical exercise protocol, performed through regular swimming sessions, inhibited cognitive impairment, memory loss and lipid peroxidation in the aged mice, while pre- and post-synaptic proteins were enhanced in the hippocampus of young and aged mice.

Dysphagia Screening in Brazilian Older Adults with Dementia: Content Development and Validation of a Questionnaire for Caregivers - RaDID-QC.

This study aims to develop and validate the content and response processes of a questionnaire intended for caregivers to screen for dysphagia in Brazilian older adults with dementia due to Alzheimer's disease and/or vascular dementia. The instrument items were developed in Brazilian Portuguese language based on the theoretical framework. A committee of speech-language-hearing therapists analyzed the relevance, objectivity, clarity, and understandability of the items with the Delphi method. The content validity index cutoff agreement score for experts' answers to validate each item in the questionnaire was 0.78; in the intraclass correlation coefficient, it was 0.75 for all items. For response process validity evidence, the questionnaire was applied to 30 caregivers of older adults with dementia, who judged the clarity and understandability of the items. Each item was validated when understood by at least 95% of participants. The first version of the instrument had 29 items. After two expert assessments, the last version had 24 items. The intraclass correlation coefficient was 0.85. Only one item needed semantic adjustments in the pre-test. The dysphagia screening instrument applied to caregivers of older adults with dementia was developed with adequate content and response process validity evidence, enabling adjustments in its construct. Future studies will analyze the remaining evidence of validity and reliability.

Unveiling a novel memory center in human brain: neurochemical identification of the nucleus incertus, a key pontine locus implicated in stress and neuropathology.

BACKGROUND: The nucleus incertus (NI) was originally described by Streeter in 1903, as a midline region in the floor of the fourth ventricle of the human brain with an 'unknown' function. More than a century later, the neuroanatomy of the NI has been described in lower vertebrates, but not in humans. Therefore, we examined the neurochemical anatomy of the human NI using markers, including the neuropeptide, relaxin-3 (RLN3), and began to explore the distribution of the NI-related RLN3 innervation of the hippocampus. METHODS: Histochemical staining of serial, coronal sections of control human postmortem pons was conducted to reveal the presence of the NI by detection of immunoreactivity (IR) for the neuronal markers, microtubule-associated protein-2 (MAP2), glutamic acid dehydrogenase (GAD)-65/67 and corticotrophin-releasing hormone receptor 1 (CRHR1), and RLN3, which is highly expressed in NI neurons in diverse species. RLN3 and vesicular GABA transporter 1 (vGAT1) mRNA were detected by fluorescent in situ hybridization. Pons sections containing the NI from an AD case were immunostained for phosphorylated-tau, to explore potential relevance to neurodegenerative diseases. Lastly, sections of the human hippocampus were stained to detect RLN3-IR and somatostatin (SST)-IR. RESULTS: In the dorsal, anterior-medial region of the human pons, neurons containing RLN3- and MAP2-IR, and RLN3/vGAT1 mRNA-positive neurons were observed in an anatomical pattern consistent with that of the NI in other species. GAD65/67- and CRHR1-immunopositive neurons were also detected within this area. Furthermore, RLN3- and AT8-IR were co-localized within NI neurons of an AD subject. Lastly, RLN3-IR was detected in neurons within the CA1, CA2, CA3 and DG areas of the hippocampus, in the absence of RLN3 mRNA. In the DG, RLN3- and SST-IR were co-localized in a small population of neurons. CONCLUSIONS: Aspects of the anatomy of the human NI are shared across species, including a population of stress-responsive, RLN3-expressing neurons and a RLN3 innervation of the hippocampus. Accumulation of phosphorylated-tau in the NI suggests its possible involvement in AD pathology. Further characterization of the neurochemistry of the human NI will increase our understanding of its functional role in health and disease.

The iceberg of dementia risk: empirical and conceptual arguments in favor of structural interventions for brain health.

While pharmacological interventions for dementia struggle to demonstrate improved outcomes for patients and at-risk populations, non-pharmacological lifestyle interventions have been proposed as a tool to achieve dementia risk reduction. In this review, it is argued that lifestyle modification alone is a surface-level intervention from the point of view of fair and far-reaching dementia prevention. Below the tip of this "iceberg of dementia risk," there are living conditions and social structures that represent deeper contributions to risk in the population. It is argued that alongside lifestyle modification, activist research and structural interventions are needed to make our society fairer and more dementia-resilient.

The potential of five c-miRNAs as serum biomarkers for Late-Onset Alzheimer's disease diagnosis: miR-10a-5p, miR-29b-2-5p, miR-125a-5p, miR-342-3p, and miR-708-5p.

The nervous system is rich in miRNAs, indicating an important role of these molecules in regulating processes associated with cognition, memory, and others. Therefore, qualitative and quantitative imbalances involving such miRNAs may be involved in dementia contexts, including Late-Onset Alzheimer's Disease (LOAD). To test the viability of circulating miRNAs (c-miRNAs) as biomarkers for LOAD, we proceed accordingly to the following reasoning. The first stage was to discover and identify profile of c-miRNAs by RNA sequencing (RNA-Seq). For this purpose, blood serum samples were used from LOAD patients (n = 5) and cognitively healthy elderly control group (CTRL_CH) (n = 5), all over 70 years old. We identified seven c-miRNAs differentially expressed (p ≤ 0.05) in the serum of LOAD patients compared to CTRL_CH (miR-10a-5p; miR-29b-2-5p; miR-125a-5p; miR-342-3p, miR-708-5p, miR-380-5p and miR-340-3p). Of these, five (p ≤ 0.01) were selected for in silico analysis (miR-10a-5p; miR-29b-2-5p; miR-125a-5p; miR-342-3p, miR-708-5p), for which 44 relevant target genes were found regulated by these c-miRNAs and related to LOAD. Through the analysis of these target genes in databases, it was possible to observe that they have functions related to the development and progress of LOAD, directly or indirectly connecting the different Alzheimer's pathways. Thus, this work found five promising serum c-miRNAs as options for biomarkers contributing to LOAD diagnosis. Our study shows the complex network between these molecules and LOAD, supporting the relevance of studies using c-miRNAs in dementia contexts.

A Systematic Review and Meta-Analysis on the Prevalence of Mild Cognitive Impairment and Dementia in Mexico.

INTRODUCTION: Age remains one of the major risk factors for the onset of mild cognitive impairment (MCI) and dementia. Studies on the prevalence of these conditions in Mexico used different methods, tools, and populations with different health statuses. All these heterogeneous results may be a problem in identifying the true prevalence of MCI and dementia in Mexico. To our knowledge, there is not a systematic review available that presents essential figures on the prevalence of these conditions in Mexico. Therefore, we intend to access the maximum number of reports published on the topic and determine the prevalence of MCI and dementia in older Mexican adults. METHODS: A systematic review using PubMed, Cochrane, Research Gate, Lilacs, and Scielo databases was performed. Meta-analysis of the prevalence of MCI and dementia was performed using a random-effects model and presented in a forest plot among cross-sectional, epidemiological, and pooled studies. RESULTS: Sixteen articles were included. The overall prevalence of MCI of 18% (95% CI 0.10-0.27) was estimated from pooled information from 12 selected studies, in women 21% (95% CI 0.08-0.38) and in men 18% (95% CI 0.06-0.33). The overall prevalence of dementia of 10% (95% CI 0.06-0.14) was estimated from pooled information from 9 selected studies, in women 14% (95% CI 0.05-0.25) and in men 10% (95% CI 0.04-0.17). CONCLUSION: Mexican older individuals have a similar prevalence of dementia and MCI as reported by international data; nevertheless, the prevalence is higher than in some Latin American countries. Mexico has particular issues that must be resolved, such as a lack of research in the southern regions of the country and the high incidence of comorbidities.

Social determinants of health but not global genetic ancestry predict dementia prevalence in Latin America.

INTRODUCTION: Leveraging the nonmonolithic structure of Latin America, which represents a large variability in social determinants of health (SDoH) and high levels of genetic admixture, we aim to evaluate the relative contributions of SDoH and genetic ancestry in predicting dementia prevalence in Latin American populations. METHODS: Community-dwelling participants aged 65 and older (N = 3808) from Cuba, Dominican Republic, Mexico, and Peru completed the 10/66 protocol assessments. Dementia was diagnosed using the cross-culturally validated 10/66 algorithm. Multivariate linear regression models adjusted for SDoH were used in the main analysis. This study used cross-sectional data from the 1066 population-based study. RESULTS: Individuals with higher proportions of Native American (>70%) and African American (>70%) ancestry were more likely to exhibit factors contributing to worse SDoH, such as lower educational levels (p < 0.001), lower socioeconomic status (p < 0.001), and higher frequency of vascular risk factors (p < 0.001). After adjusting for measures of SDoH, there was no association between ancestry proportion and dementia probability, and ancestry proportions no longer significantly accounted for the variance in cognitive performance (African predominant p = 0.31 [-0.19, 0.59] and Native predominant p = 0.74 [-0.24, 0.33]). DISCUSSION: The findings suggest that social and environmental factors play a more crucial role than genetic ancestry in predicting dementia prevalence in Latin American populations. This underscores the need for public health strategies and policies that address these social determinants to effectively reduce dementia risk in these communities. HIGHLIGHTS: Countries in Latin America express a large variability in social determinants of health and levels of admixture. After adjustment for downstream societal factors linked to SDoH, genetic ancestry shows no link to dementia. Population ancestry profiles alone do not influence cognitive performance. SDoH are key drivers of racial disparities in dementia and cognitive performance.

Language impairments in Alzheimer´s disease: What changes can be found between mild and moderate stages of the disease?

OBJECTIVE: To investigate how language deteriorates over the Alzheimer's Disease course. METHODS: A cross-sectional, observational study was carried out. 35 patients diagnosed with dementia due to AD using the NINCDS-ARDRA criteria and undergoing treatment for AD with a therapeutic dose of acetylcholinesterase inhibitors were assessed by the Boston Diagnostic Aphasia Examination (BDAE). The sample comprised 15 patients with mild AD (MMSE > 23, CDR = 0 or 0.5‒1.0) and 20 patients with moderate AD (MMSE = 13‒23, CDR = 2). The results for the 2 groups on all language tasks were compared. RESULTS: A statistically significant difference was found between the mild and moderate AD groups for total score on the BDAE (95% CI 47.10‒114.08, t = 5.0, DF = 21, p = 0.000*), as well as on several tasks involving oral and writing comprehension, language oral expression and writing. CONCLUSION: The study results showed major changes in the moderate stage. Also, the decline in language performance correlated with the worsening of dementia syndrome, independently of sociodemographic variables.