Millipore xMap® Luminex (HATMAG-68K): An Accurate and Cost-Effective Method for Evaluating Alzheimer's Biomarkers in Cerebrospinal Fluid.

Background: Alzheimer's disease (AD) biomarkers are of great relevance in clinical research, especially after the AT(N) framework. They enable early diagnosis, disease staging and research with new promising drugs, monitoring therapeutic response. However, the high cost and low availability of the most well-known methods limits their use in low and medium-income countries. In this context, Millipore xMap® Luminex may be a cost-effective alternative. In our study, using INNOTEST® as reference, we assess the diagnostic accuracy of Millipore xMap® and propose a cutoff point for AD. Methods: We performed lumbar puncture of seven older individuals with clinically defined AD, 17 with amnestic mild cognitive impairment (aMCI) and 11 without objective cognitive impairment-control group (CG). Cerebrospinal fluid (CSF) biomarkers concentrations for aB42, p-Tau, and t-Tau were measured by INNOTEST® and Millipore xMap®, and then the techniques were compared to assess the diagnostic accuracy of the new test and to define a cutoff. Results: INNOTEST® and Millipore xMap® measurements showed all correlations >0.8 for the same biomarker, except for t-Tau that was 0.66. Millipore xMap® measurements showed a robust accuracy for all biomarkers, with AUC higher than 0.808 (t-Tau), and the best for Aß42 (AUC = 0.952). The most accurate cutoffs were found at 1012.98 pg/ml (Aß42), 64.54 pg/ml (p-tau), 3251.81 pg/ml (t-tau), 3.370 (t-Tau/Aß42), and 0.059 (p-Tau/Aß42). Conclusion: Given its good accuracy and cost-effectiveness, Milliplex xMap® tests seems a reliable and promising tool, especially for low and middle-income countries.

Insomnia and risk of dementia in older adults: Systematic review and meta-analysis.

There are cross-sectional evidences of an association between sleep disorders and cognitive impairment on older adults. However, there are no consensus by means of longitudinal studies data on the increased risk of developing dementia related to insomnia. We conduct a systematic review and meta-analysis to evaluate the risk of incident all-cause dementia in individuals with insomnia in population-based prospective cohort studies. Five studies of 5.242 retrieved references were included in the meta-analysis. We used the generic inverse variance method with a random effects model to calculate the pooled risk of dementia in older adults with insomnia. We assessed heterogeneity in the meta-analysis by means of the Q-test and I2 index. Study quality was assessed with the Newcastle-Ottawa Scale The results showed that Insomnia was associated with a significant risk of all-cause dementia (RR = 1.53 CI95% (1.07-2.18), z = 2.36, p = 0.02). There was evidence for significant heterogeneity in the analysis (q-value = 2.4, p < 0.001 I2 = 82%). Insomnia is associated with an increased risk for dementia. This results provide evidences that future studies should investigate dementia prevention among elderly individuals through screening and proper management of insomnia.

Validity and reliability of a "simplified" version of the Taylor Complex Figure Test for the assessment of older adults with low formal education / Validade e confiabilidade de uma versão "simplificada" da Figura Complexa de Taylor para a avaliação dos idosos com baixa escolaridade

Objective : The assessment of visuospatial abilities and memory using tasks such as the Taylor Complex Figure Task (TCFT) is biased for older adults with low formal education. We devised a "Simplified" version of the TCFT designed to assess older adults with low educational background and provide preliminary evidence of its psychometric properties. Methods : We evaluated a heterogeneous sample of healthy older adults and patients with mild cognitive impairment and Alzheimer's disease dementia using the simplified TCFT and other neuropsychological measures. Results : Our results suggest that the test copy, immediate and delayed recall have high inter-rater agreement and internal consistency, significant correlations with other tests of visuospatial abilities, memory and intelligence, and also detected significant group differences between controls and patients. Conclusion : Our study presents a new measure for assessing low-educated elderly with promising evidence of validity and reliability.

Objetivo : A avaliação de habilidades visioespaciais e de memória por tarefas como a Figura Complexa Taylor (FCT) é enviesada para de idosos com baixa escolarização formal. Propomos uma versão "simplificada" da FCT (FCTs) projetada para a avaliação dos idosos com baixo nível educacional e apresentamos evidências preliminares de suas propriedades psicométricas. Métodos : Avaliamos uma amostra heterogênea de idosos saudáveis e pacientes com comprometimento cognitivo leve e demência por Doença de Alzheimer usando a FCTs e outras medidas neuropsicológicas. Resultados : Nossos resultados sugerem que a cópia de teste, a evocação imediata e a evocação tardia têm alta concordância entre avaliadores e elevada consistência interna, apresentam correlações significativas com outros testes de habilidades visioespaciais, memória e inteligência, além de documentarem diferenças significativas entre o grupo controles e os pacientes. Conclusão : Nosso estudo apresenta uma nova medida para a avaliação neuropsicológica de idosos com baixa escolaridade, com evidências promissoras de validade e confiabilidade.

Validity and reliability of a "simplified" version of the Taylor Complex Figure Test for the assessment of older adults with low formal education.

OBJECTIVE: The assessment of visuospatial abilities and memory using tasks such as the Taylor Complex Figure Task (TCFT) is biased for older adults with low formal education. We devised a "Simplified" version of the TCFT designed to assess older adults with low educational background and provide preliminary evidence of its psychometric properties. METHODS: We evaluated a heterogeneous sample of healthy older adults and patients with mild cognitive impairment and Alzheimer's disease dementia using the simplified TCFT and other neuropsychological measures. RESULTS: Our results suggest that the test copy, immediate and delayed recall have high inter-rater agreement and internal consistency, significant correlations with other tests of visuospatial abilities, memory and intelligence, and also detected significant group differences between controls and patients. CONCLUSION: Our study presents a new measure for assessing low-educated elderly with promising evidence of validity and reliability.

OBJETIVO: A avaliação de habilidades visioespaciais e de memória por tarefas como a Figura Complexa Taylor (FCT) é enviesada para de idosos com baixa escolarização formal. Propomos uma versão "simplificada" da FCT (FCTs) projetada para a avaliação dos idosos com baixo nível educacional e apresentamos evidências preliminares de suas propriedades psicométricas. MÉTODOS: Avaliamos uma amostra heterogênea de idosos saudáveis e pacientes com comprometimento cognitivo leve e demência por Doença de Alzheimer usando a FCTs e outras medidas neuropsicológicas. RESULTADOS: Nossos resultados sugerem que a cópia de teste, a evocação imediata e a evocação tardia têm alta concordância entre avaliadores e elevada consistência interna, apresentam correlações significativas com outros testes de habilidades visioespaciais, memória e inteligência, além de documentarem diferenças significativas entre o grupo controles e os pacientes. CONCLUSÃO: Nosso estudo apresenta uma nova medida para a avaliação neuropsicológica de idosos com baixa escolaridade, com evidências promissoras de validade e confiabilidade.

The Stick Design Test on the assessment of older adults with low formal education: evidences of construct, criterion-related and ecological validity.

BACKGROUND: The assessment of visuospatial abilities is usually performed by drawing tasks. In patients with very low formal education, the use of these tasks might be biased by their cultural background. The Stick Design Test was developed for the assessment of this population. We aim to expand the test psychometric properties by assessing its construct, criterion-related and ecological validity in older adults with low formal education. METHOD: Healthy older adults (n = 63) and Alzheimer's disease patients (n = 92) performed the Stick Design Test, Mini-Mental State Examination, Digit Span Forward and the Clock Drawing Test. Their caregivers answered Personal Care and Instrumental Activities of Daily Living). Construct validity was assessed by factor analysis, convergent correlations (with the Clock Drawing Test), and divergent correlations (with Digit Span Forward); criterion-related validity by receiver operating characteristic curve analysis and binary logistic regression; and Ecological validity by correlations with ADL. RESULTS: The test factor structure was composed by one component (R 2 = 64%). Significant correlations with the Clock Drawing Test and Digit Span Forward were found, and the relationship was stronger with the first measure. The test was less associated with formal education than the Clock Drawing Test. It classified about 76% of the participants correctly and had and additive effect with the Mini-Mental State Examination (84% of correct classification). The test also correlated significantly with measures of ADL, suggesting ecological validity. CONCLUSIONS: The Stick Design Test shows evidence of construct, criterion-related and ecological validity. It is an interesting alternative to drawing tasks for the assessment of visuospatial abilities.