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OBJECTIVE: The performances of popular genome-wide association study (GWAS) models have not been examined yet in a consistent manner under the scenario of genetic admixture, which introduces several challenging aspects: heterogeneity of minor allele frequency (MAF), wide spectrum of case-control ratio, varying effect sizes, etc. METHODS: We generated a cohort of synthetic individuals (N = 19 234) that simulates (i) a large sample size; (ii) two-way admixture (Native American and European ancestry) and (iii) a binary phenotype. We then benchmarked three popular GWAS tools [generalized linear mixed model associated test (GMMAT), scalable and accurate implementation of generalized mixed model (SAIGE) and Tractor] by computing inflation factors and power calculations under different MAFs, case-control ratios, sample sizes and varying ancestry proportions. We also employed a cohort of Peruvians (N = 249) to further examine the performances of the testing models on (i) real genetic and phenotype data and (ii) small sample sizes. RESULTS: In the synthetic cohort, SAIGE performed better than GMMAT and Tractor in terms of type-I error rate, especially under severe unbalanced case-control ratio. On the contrary, power analysis identified Tractor as the best method to pinpoint ancestry-specific causal variants but showed decreased power when the effect size displayed limited heterogeneity between ancestries. In the Peruvian cohort, only Tractor identified two suggestive loci (P-value $\le 1\ast{10}^{-5}$) associated with Native American ancestry. DISCUSSION: The current study illustrates best practice and limitations for available GWAS tools under the scenario of genetic admixture. Incorporating local ancestry in GWAS analyses boosts power, although careful consideration of complex scenarios (small sample sizes, imbalance case-control ratio, MAF heterogeneity) is needed.
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Benchmarking , Estudo de Associação Genômica Ampla , Humanos , Estudo de Associação Genômica Ampla/métodos , Frequência do Gene , Fenótipo , Tamanho da Amostra , Polimorfismo de Nucleotídeo ÚnicoRESUMO
INTRODUCTION: People caring for patients with dementia are prone to suffering from burden. Behavioral and psychological symptoms of dementia (BPSD) may have an impact on caregiver burden. In Latin American countries, there is a lack of research on caregiver burden. We aimed to determine which BPSD have the greatest impact on caregiver burden among Peruvian patients with dementia and to compare the effects of BPSD on caregiver burden across different types of dementia. METHODS: A cross-sectional study was conducted on 231 patients living with Alzheimer's dementia (AD), behavioral variant frontotemporal dementia (bvFTD), dementia with Lewy bodies (DLB), and vascular dementia (VD) and their caregivers who attended a Peruvian memory clinic. BPSD were assessed with the Neuropsychiatric Inventory (NPI). Caregiver burden was assessed with the Zarit Burden Inventory. We used analysis of variance to compare the AD, bvFTD, DLB, and VD groups. Correlations between Zarit Burden Inventory and NPI subscale scores were assessed with Spearman's correlation. RESULTS: DLB caregivers had significantly higher levels of burden than the other patient groups (p < 0.05) and higher total NPI scores than caregivers for other patient groups (p < 0.05). bvFTD caregivers had significantly higher total NPI scores than AD and VD caregivers (p < 0.05). Hallucinations, aberrant motor behavior, and apathy were the symptoms most significantly correlated with caregiver burden in those caring for DLB, bvFTD, and AD patients, respectively. CONCLUSION: Neuropsychiatric symptoms are higher in DLB caregivers. Hallucinations, aberrant motor behavior, and apathy are the main symptoms correlated with burden.
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INTRODUCTION: While Latin America (LatAm) is facing an increasing burden of dementia due to the rapid aging of the population, it remains underrepresented in dementia research, diagnostics, and care. METHODS: In 2023, the Alzheimer's Association hosted its eighth satellite symposium in Mexico, highlighting emerging dementia research, priorities, and challenges within LatAm. RESULTS: Significant initiatives in the region, including intracountry support, showcased their efforts in fostering national and international collaborations; genetic studies unveiled the unique genetic admixture in LatAm; researchers conducting emerging clinical trials discussed ongoing culturally specific interventions; and the urgent need to harmonize practices and studies, improve diagnosis and care, and use affordable biomarkers in the region was highlighted. DISCUSSION: The myriad of topics discussed at the 2023 AAIC satellite symposium highlighted the growing research efforts in LatAm, providing valuable insights into dementia biology, genetics, epidemiology, treatment, and care.
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Demência , Humanos , Demência/terapia , Demência/diagnóstico , Demência/genética , Demência/epidemiologia , América Latina/epidemiologia , México/epidemiologia , Doença de Alzheimer/terapia , Doença de Alzheimer/diagnóstico , Doença de Alzheimer/genética , Pesquisa Biomédica , Congressos como AssuntoRESUMO
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.
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INTRODUCTION: As disease-modifying therapies become available for Alzheimer's disease (AD), detection of AD in early stages of illness (mild cognitive impairment [MCI], early dementia) becomes increasingly important. Biomarkers for AD in low- and middle-income countries (LMICs) are costly and not widely available; hence, it is important to identify cognitive tests that correlate well with AD biomarker status. In this study, we evaluated the memory alteration test (M@T) to detect biomarker-proven AD and quantify its correlation with neurodegeneration and cerebrospinal fluid (CSF) AD biomarkers in a cohort of participants from Lima, Peru. METHODS: This is a secondary analysis of a cohort of 185 participants: 63 controls, 53 with amnestic MCI (aMCI), and 69 with dementia due to AD. Participants underwent testing with M@T and a gold standard neuropsychological battery. We measured total tau (t-tau), phosphorylated tau (p-tau), and beta-amyloid (ß-amyloid) in CSF, and evaluated neurodegeneration via medial temporal atrophy score in MRI. We used receiver-operator curves to determine the discriminative capacity of the total M@T score and its subdomains. We used the Pearson coefficient to correlate M@T score and CSF biomarkers. RESULTS: The M@T had an area under the curve (AUC) of 0.994 to discriminate between controls and cognitively impaired (aMCI or AD) patients, and an AUC of 0.98 to differentiate between aMCI and AD patients. Free-recall and cued recall had the highest AUCs of all subdomains. Total score was strongly correlated with t-tau (-0.77) and p-tau (-0.72), and moderately correlated with ß-amyloid (0.66). The AUC for discrimination of neurodegeneration was 0.87. CONCLUSION: The M@T had excellent discrimination of aMCI and dementia due to AD. It was strongly correlated with CSF biomarkers and had good discrimination of neurodegeneration. In LMICs, the M@T may be a cost-effective screening tool for aMCI and dementia caused by AD.
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Doença de Alzheimer , Disfunção Cognitiva , Humanos , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/líquido cefalorraquidiano , Peru , Proteínas tau/líquido cefalorraquidiano , Encéfalo , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Disfunção Cognitiva/diagnóstico por imagem , Disfunção Cognitiva/líquido cefalorraquidiano , Biomarcadores/líquido cefalorraquidiano , Neuroimagem , Fragmentos de Peptídeos/líquido cefalorraquidianoRESUMO
Limited knowledge on dementia biomarkers in Latin American and Caribbean (LAC) countries remains a serious barrier. Here, we reported a survey to explore the ongoing work, needs, interests, potential barriers, and opportunities for future studies related to biomarkers. The results show that neuroimaging is the most used biomarker (73%), followed by genetic studies (40%), peripheral fluids biomarkers (31%), and cerebrospinal fluid biomarkers (29%). Regarding barriers in LAC, lack of funding appears to undermine the implementation of biomarkers in clinical or research settings, followed by insufficient infrastructure and training. The survey revealed that despite the above barriers, the region holds a great potential to advance dementia biomarkers research. Considering the unique contributions that LAC could make to this growing field, we highlight the urgent need to expand biomarker research. These insights allowed us to propose an action plan that addresses the recommendations for a biomarker framework recently proposed by regional experts.
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Demência , Humanos , América Latina , Demência/diagnósticoRESUMO
INTRODUCTION: Latin American Initiative for Lifestyle Intervention to Prevent Cognitive Decline (LatAm-FINGERS) is the first non-pharmacological multicenter randomized clinical trial (RCT) to prevent cognitive impairment in Latin America (LA). Our aim is to present the study design and discuss the strategies used for multicultural harmonization. METHODS: This 1-year RCT (working on a 1-year extension) investigates the feasibility of a multi-domain lifestyle intervention in LA and the efficacy of the intervention, primarily on cognitive function. An external harmonization process was carried out to follow the FINGER model, and an internal harmonization was performed to ensure this study was feasible and comparable across the 12 participating LA countries. RESULTS: Currently, 1549 participants have been screened, and 815 randomized. Participants are ethnically diverse (56% are Nestizo) and have high cardiovascular risk (39% have metabolic syndrome). DISCUSSION: LatAm-FINGERS overcame a significant challenge to combine the region's diversity into a multi-domain risk reduction intervention feasible across LA while preserving the original FINGER design.
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Disfunção Cognitiva , Humanos , América Latina , Disfunção Cognitiva/prevenção & controle , Estilo de Vida , Cognição , Projetos de PesquisaRESUMO
INTRODUCTION: To evaluate the diagnostic accuracy of three brief cognitive screening (BCS) tools, Peruvian version of Addenbrooke's Cognitive Examination (ACE-Pe), of INECO Frontal Screening (IFS-Pe) and of the Mini-Mental State Examination (MMSE-Pe), for the diagnosis of vascular cognitive impairment (VCI) and its non-dementia stages (VCI-ND) and vascular dementia (VD) in patients with cerebral stroke in Lima-Peru. MATERIALS AND METHODS: A cohort analysis to evaluate the diagnostic accuracy of three BCS for VCI. RESULTS: Two hundred and four patients were evaluated: 61% Non-VCI, 30% VCI-ND and 9% VD. To discriminate patients with VCI from controls, the area under the curve (AUC) of ACE-Pe, IFS-Pe and MMs-Pe were 0.99 (95% confidence interval [CI] 0.98-0.99), 0.99 (95%CI 0.98-0.99) and 0.87 (95%CI 0.82-0.92), respectively. Of the three BCS, the IFS-Pe presented a larger AUC to discriminate VCI-ND from VD (AUC = 0.98 [95%CI 0.95-1]) compared to ACE-Pe (AUC = 0.84 [95%CI 0.74-0.95]) and MMSE-Pe (0.92 [95%CI 0.86-0.99]). The IFS-Pe presented a higher sensitivity (S), specificity (Sp), and positive (+LR) and negative likelihood ratios (-LR) (S = 96.72%, Sp = 89.47%, +LR = 9.1 and -LR = 0.03) than ACE-Pe (S = 96.72%, Sp = 63.16%, +LR = 2.62 and -LR = 0.05) and MMSE-Pe (S = 90.16%, Sp = 78.95%, +LR = 4.28 and -LR = 0.12). In the multiple regression analysis, the IFS-Pe was not affected by age, sex or years of schooling. CONCLUSION: The IFS-Pe has the best diagnostic accuracy for detecting VCI and discriminating between pre-dementia (VCI-ND) and dementia (VD) stages.
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Disfunção Cognitiva , Demência Vascular , Cognição , Disfunção Cognitiva/diagnóstico , Demência Vascular/diagnóstico , Humanos , Testes de Estado Mental e Demência , Testes Neuropsicológicos , PeruRESUMO
BACKGROUND: There is debate as to whether there is an increased risk of COVID-19 infection in people with Parkinson's disease (PD), possibly due to associated factors. This study aimed to systematically review the factors associated with COVID-19 in people with PD. METHODS: A search was carried out in PubMed, Scopus, and Web of Science up to November 2020 (updated until 1 April 2021). Observational studies that analyzed factors associated with COVID-19 in people with PD were selected and revised. RESULTS: The authors included six studies (four case-controlled studies and two cross-sectional studies) in the qualitative and quantitative syntheses. The authors found that the following factors were associated with COVID-19 in people with PD: obesity (OR: 1.79, 95% CI: 1.07-2.99, I2 : 0%), any pulmonary disease (OR: 1.92, 95% CI: 1.17-3.15, I2 : 0%), COVID-19 contact (OR: 41.77, 95% CI: 4.77 - 365.56, I2 : 0%), vitamin D supplementation (OR: 0.50, 95% CI: 0.30-0.83, I2 : 0%), hospitalization (OR: 11.78, 95% CI: 6.27-22.12, I2 : 0%), and death (OR: 11.23, 95% CI: 3.92-32.18, I2 : 0%). The authors did not find any significant association between COVID-19 and hypertension, diabetes, cardiopathy, cancer, any cognitive problem, dementia, chronic obstructive pulmonary disease, renal or hepatic disease, smoking, and tremor. CONCLUSIONS: Meta-analyses were limited by the number of events and some methodological limitations. Despite this, the authors assessed the available evidence, and the results may be useful for future health policies.
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COVID-19 , Diabetes Mellitus , Doença de Parkinson , Estudos Transversais , Humanos , Doença de Parkinson/complicações , Doença de Parkinson/epidemiologia , SARS-CoV-2RESUMO
Across Latin American and Caribbean countries (LACs), the fight against dementia faces pressing challenges, such as heterogeneity, diversity, political instability, and socioeconomic disparities. These can be addressed more effectively in a collaborative setting that fosters open exchange of knowledge. In this work, the Latin American and Caribbean Consortium on Dementia (LAC-CD) proposes an agenda for integration to deliver a Knowledge to Action Framework (KtAF). First, we summarize evidence-based strategies (epidemiology, genetics, biomarkers, clinical trials, nonpharmacological interventions, networking, and translational research) and align them to current global strategies to translate regional knowledge into transformative actions. Then we characterize key sources of complexity (genetic isolates, admixture in populations, environmental factors, and barriers to effective interventions), map them to the above challenges, and provide the basic mosaics of knowledge toward a KtAF. Finally, we describe strategies supporting the knowledge creation stage that underpins the translational impact of KtAF.
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Demência/terapia , Prática Clínica Baseada em Evidências , Biomarcadores , Demência/epidemiologia , Humanos , América Latina/epidemiologia , Fatores SocioeconômicosRESUMO
Introduction: The COVID-19 pandemic, with over 83 million confirmed cases and 1.8 million deaths, has raised concerns about long-term cognitive issues, especially in populations facing disparities. Despite a few years since Peru's first COVID-19 wave, the cognitive effects on adults remain unclear. This study is the first in Peru to explore COVID-19's impact on general cognition and executive function. Methods: A retrospective cross-sectional study compared individuals with COVID-19 history to controls, assessing general cognition, verbal fluency, attention, and executive function. Among 240 assessed, 154 met the study inclusion criteria, with about 60% female and an average age of 38.89 ± 16.001 years. Groups included controls (n = 42), acute phase (AP, n = 74) (1-14 days of symptoms), and hyperinflammatory phase (HP, n = 38) (>14 days of symptoms). Results: Significant cognitive differences were observed. The HP group exhibited lower general cognitive performance (p = 0.02), working memory (p = 0.01), and executive function (planning; p < 0.001; flexibility; p = 0.03) than controls. Those with <14 days of illness (AP vs. HP) had deficits in general cognitive performance (p = 0.02), working memory (p = 0.02), and planning (p < 0.001), mainly during the hyperinflammatory phase, showing differences in working memory (p = 0.003) and planning (p = 0.01). Gender differences emerged, with males in the HP phase having poorer working memory (p = 0.003) and planning (p = 0.01). Discussion: This study underscores COVID-19's negative impact on cognitive function, even in mild cases, with potential heightened effects in men during acute or hyperinflammatory phases. The findings provide Peru's first evidence, highlighting the vulnerability of populations facing socioeconomic disparities.
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Background: In Latin America (LA), the prevalence of dementia is expected to triple to 150 million people by 2050. The 2020 Lancet Commission report identified several modifiable dementia risk factors, yet few social and environmental factors, most relevant to vulnerable regions of LA, were highlighted in this report. We sought to assess the epidemiology of neurocognitive disorders (NCD) in Puente Piedra, one of the most socially and economically vulnerable districts of Lima, the capital of Peru. Methodology: This was a cross-sectional door-to-door observational study that used two-stage household sampling. One young adult (30-59 years) and one older adult (>60 years) per household were enrolled. We collected demographic, clinical, and neurocognitive data. Addenbrooke's Cognitive Examination (young adults) and the RUDAS-PE (older adults) were used, classifying participants as cognitively normal, possible mild NCD, or possible major NCD. Results: We enrolled 247 participants (median age 46 years; 67% female). One-fourth had not completed secondary school and more than 50% completed only secondary school. Most participants were housewives (46%) and 21% did not have health insurance. The overall prevalence of possible NCD was 30% (25.6 and 41.8% among younger adults and older adults, respectively). Among younger adults, those ages 55-59 years more frequently had NCD (70%) compared to younger age ranges. Among older adults, only 3 subjects (4.5%) had major NCD. Conclusion: We found a high frequency of possible NCDs in a socially and economically vulnerable community in Lima, Peru, with younger adults showing levels of NCD higher than expected. Our findings support the need for health systems to incorporate cognitive screenings programs for NCD in younger ages. Future research on NCD would include younger populations, particularly in vulnerable communities.
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Demência , Piedra , Adulto Jovem , Humanos , Feminino , Idoso , Pessoa de Meia-Idade , Masculino , Peru/epidemiologia , Estudos Transversais , Transtornos Neurocognitivos/epidemiologia , Transtornos Neurocognitivos/diagnósticoRESUMO
BACKGROUND: Neuropsychiatric symptoms (NPS) in patients with Alzheimer's disease (AD) worsened during the COVID-19 lockdowns, but their progression thereafter is unknown. We present the first longitudinal study tracking them before, during, and after restrictions. OBJECTIVES: To describe the effect of the COVID-19 mandatory lockdowns on Cognitive and Neuropsychiatric symptoms in patients with Mild Cognitive Impairment (MCI) and Alzheimer's Disease (AD). METHODS: Cohort of 48 patients with amnestic MCI and 38 with AD in Lima, Peru. They received three rounds of cognitive (RUDAS, CDR, M@T), behavioral (NPI), and functional (ADCS-ADL) assessments. We assessed the change in score means across the time points and for each domain of NPS and tracked the changes in individual patients. RESULTS: RUDAS declined 0.9 (SD 1.0) from baseline to lockdown and 0.7 (SD 1.0) after restrictions. M@T declined 1.0 (SD 1.5) from baseline to lockdown and 1.4 (SD 2.0) after restrictions. CDR worsened in 72 patients (83.72%) from baseline to post-lockdown. NPI worsened by 10 (SD 8.3) from baseline to lockdown but improved by 4.8 (SD 6.4) after restrictions. Proportionally, 81.3% of all patients had worsened NPS during the lockdowns, but only 10.7% saw an increase thereafter. Improvement was statistically significant for specific NPS domains except hallucinations, delusions, and appetite changes. Anxiety, irritability, apathy, and disinhibition returned to baseline levels. CONCLUSION: Following confinement, cognition continued to decline, but NPS demonstrated either stability or improvement. This highlights the role modifiable risk factors may have on the progression of NPS.
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Doença de Alzheimer , COVID-19 , Disfunção Cognitiva , Humanos , Doença de Alzheimer/diagnóstico , Estudos Longitudinais , Peru/epidemiologia , Testes Neuropsicológicos , Controle de Doenças Transmissíveis , Disfunção Cognitiva/diagnóstico , CogniçãoRESUMO
Objective: The performances of popular Genome-wide association study (GWAS) models haven't been examined yet in a consistent manner under the scenario of genetic admixture, which introduces several challenging aspects such as heterogeneity of minor allele frequency (MAF), a wide spectrum of case-control ratio, and varying effect sizes etc. Methods: We generated a cohort of synthetic individuals (N=19,234) that simulates 1) a large sample size; 2) two-way admixture [Native American-European ancestry] and 3) a binary phenotype. We then examined the inflation factors produced by three popular GWAS tools: GMMAT, SAIGE, and Tractor. We also computed power calculations under different MAFs, case-control ratios, and varying ancestry percentages. Then, we employed a cohort of Peruvians (N=249) to further examine the performances of the testing models on 1) real genetic data and 2) small sample sizes. Finally, we validated these findings using an independent Peruvian cohort (N=109) included in 1000 Genome project (1000G). Results: In the synthetic cohort, SAIGE performed better than GMMAT and Tractor in terms of type-I error rate, especially under severe unbalanced case-control ratio. On the contrary, power analysis identified Tractor as the best method to pinpoint ancestry-specific causal variants, but showed decreased power when no adequate heterogeneity of the true effect sizes was simulated between ancestries. The real Peruvian data showed that Tractor is severely affected by small sample sizes, and produced severely inflated statistics, which we replicated in the 1000G Peruvian cohort. Discussion: The current study illustrates the limitations of available GWAS tools under different scenarios of genetic admixture. We urge caution when interpreting results under complex population scenarios.
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Alzheimer's disease (AD) represents a substantial burden to patients, their caregivers, health systems, and society in Latin America and the Caribbean (LAC). This impact is exacerbated by limited access to diagnosis, specialized care, and therapies for AD within and among nations. The region has varied geographic, ethnic, cultural, and economic conditions, which create unique challenges to AD diagnosis and management. To address these issues, the Americas Health Foundation convened a panel of eight neurologists, geriatricians, and psychiatrists from Argentina, Brazil, Colombia, Ecuador, Guatemala, Mexico, and Peru who are experts in AD for a three-day virtual meeting to discuss best practices for AD diagnosis and treatment in LAC and create a manuscript offering recommendations to address identified barriers. In LAC, several barriers hamper diagnosing and treating people with dementia. These barriers include access to healthcare, fragmented healthcare systems, limited research funding, unstandardized diagnosis and treatment, genetic heterogeneity, and varying social determinants of health. Additional training for physicians and other healthcare workers at the primary care level, region-specific or adequately adapted cognitive tests, increased public healthcare insurance coverage of testing and treatment, and dedicated search strategies to detect populations with gene variants associated with AD are among the recommendations to improve the landscape of AD.
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Aging may diminish social cognition, which is crucial for interaction with others, and significant changes in this capacity can indicate pathological processes like dementia. However, the extent to which non-specific factors explain variability in social cognition performance, especially among older adults and in global settings, remains unknown. A computational approach assessed combined heterogeneous contributors to social cognition in a diverse sample of 1063 older adults from 9 countries. Support vector regressions predicted the performance in emotion recognition, mentalizing, and a total social cognition score from a combination of disparate factors, including clinical diagnosis (healthy controls, subjective cognitive complaints, mild cognitive impairment, Alzheimer's disease, behavioral variant frontotemporal dementia), demographics (sex, age, education, and country income as a proxy of socioeconomic status), cognition (cognitive and executive functions), structural brain reserve, and in-scanner motion artifacts. Cognitive and executive functions and educational level consistently emerged among the top predictors of social cognition across models. Such non-specific factors showed more substantial influence than diagnosis (dementia or cognitive decline) and brain reserve. Notably, age did not make a significant contribution when considering all predictors. While fMRI brain networks did not show predictive value, head movements significantly contributed to emotion recognition. Models explained between 28-44% of the variance in social cognition performance. Results challenge traditional interpretations of age-related decline, patient-control differences, and brain signatures of social cognition, emphasizing the role of heterogeneous factors. Findings advance our understanding of social cognition in brain health and disease, with implications for predictive models, assessments, and interventions.
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The Latin American Brain Health Institute (BrainLat) has released a unique multimodal neuroimaging dataset of 780 participants from Latin American. The dataset includes 530 patients with neurodegenerative diseases such as Alzheimer's disease (AD), behavioral variant frontotemporal dementia (bvFTD), multiple sclerosis (MS), Parkinson's disease (PD), and 250 healthy controls (HCs). This dataset (62.7 ± 9.5 years, age range 21-89 years) was collected through a multicentric effort across five Latin American countries to address the need for affordable, scalable, and available biomarkers in regions with larger inequities. The BrainLat is the first regional collection of clinical and cognitive assessments, anatomical magnetic resonance imaging (MRI), resting-state functional MRI (fMRI), diffusion-weighted MRI (DWI), and high density resting-state electroencephalography (EEG) in dementia patients. In addition, it includes demographic information about harmonized recruitment and assessment protocols. The dataset is publicly available to encourage further research and development of tools and health applications for neurodegeneration based on multimodal neuroimaging, promoting the assessment of regional variability and inclusion of underrepresented participants in research.
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Doença de Alzheimer , Encéfalo , Adulto , Idoso , Idoso de 80 Anos ou mais , Humanos , Pessoa de Meia-Idade , Adulto Jovem , Doença de Alzheimer/diagnóstico por imagem , Encéfalo/patologia , Imagem de Difusão por Ressonância Magnética/métodos , Imageamento por Ressonância Magnética/métodos , NeuroimagemRESUMO
Background: Global brain health initiatives call for improving methods for the diagnosis of Alzheimer's disease (AD) and frontotemporal dementia (FTD) in underrepresented populations. However, diagnostic procedures in upper-middle-income countries (UMICs) and lower-middle income countries (LMICs), such as Latin American countries (LAC), face multiple challenges. These include the heterogeneity in diagnostic methods, lack of clinical harmonisation, and limited access to biomarkers. Methods: This cross-sectional observational study aimed to identify the best combination of predictors to discriminate between AD and FTD using demographic, clinical and cognitive data among 1794 participants [904 diagnosed with AD, 282 diagnosed with FTD, and 606 healthy controls (HCs)] collected in 11 clinical centres across five LAC (ReDLat cohort). Findings: A fully automated computational approach included classical statistical methods, support vector machine procedures, and machine learning techniques (random forest and sequential feature selection procedures). Results demonstrated an accurate classification of patients with AD and FTD and HCs. A machine learning model produced the best values to differentiate AD from FTD patients with an accuracy = 0.91. The top features included social cognition, neuropsychiatric symptoms, executive functioning performance, and cognitive screening; with secondary contributions from age, educational attainment, and sex. Interpretation: Results demonstrate that data-driven techniques applied in archival clinical datasets could enhance diagnostic procedures in regions with limited resources. These results also suggest specific fine-grained cognitive and behavioural measures may aid in the diagnosis of AD and FTD in LAC. Moreover, our results highlight an opportunity for harmonisation of clinical tools for dementia diagnosis in the region. Funding: This work was supported by the Multi-Partner Consortium to Expand Dementia Research in Latin America (ReDLat), funded by NIA/NIH (R01AG057234), Alzheimer's Association (SG-20-725707-ReDLat), Rainwater Foundation, Takeda (CW2680521), Global Brain Health Institute; as well as CONICET; FONCYT-PICT (2017-1818, 2017-1820); PIIECC, Facultad de Humanidades, Usach; Sistema General de Regalías de Colombia (BPIN2018000100059), Universidad del Valle (CI 5316); ANID/FONDECYT Regular (1210195, 1210176, 1210176); ANID/FONDAP (15150012); ANID/PIA/ANILLOS ACT210096; and Alzheimer's Association GBHI ALZ UK-22-865742.
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INTRODUCTION: The development of screening tools for the assessment of cognitive status in patients with dementia must be brief yet both highly sensitive and specific in order to ensure its clinical utility. In this sense, it is important to adapt tools widely used around the world to particular populations, allowing for a more proper validity of its use in everyday clinical practice. One of the most popular general cognitive screening tools is the Addenbrooke's Cognitive Examination (ACE), which has been adapted and validated in multiple languages and populations. OBJECTIVE: To assess the usefulness of the Peruvian version of the ACE in patients with dementia. MATERIALS AND METHODS: Healthy controls, patients with Alzheimer disease (AD) and patients with Frontotemporal Dementia (FTD) were assessed with the Peruvian version of the ACE, the ADAScog to determine dementia severity, and a complete neuropsychological battery. RESULTS: The Peruvian version of the ACE showed very good internal consistency, strong concurrent validity as revealed by significant correlations between the ACE total score and both the MMSE and ADAScog. The ACE was able to differentiate healthy controls from patients with dementia with high discriminatory accuracy. Using a cut-off score of 86 (out of 100), the ACE was exhibited a sensitivity of 100% and a specificity of 100%.