The cognitive reserve (CR) is widely accepted as the active ability to cope with brain damage, using preexisting cognitive and compensatory processes. The common CR proxies used are the number of formal years of education, intelligence quotient (IQ) or premorbid functioning, occupation attainment, and participation in leisure activities. More recently, it has employed the level of literacy and engagement in high-level cognitive demand of professional activities. This study aims to identify and summarize published methodologies to assess the CR quantitatively. We searched for published studies on PubMed, ScienceDirect, and Web of Science between September 2018 and September 2021. We only included those studies that characterized the CR assessment methodology. The search strategy identified 1,285 publications, of which 25 were included. Most of the instruments targeted proxies individually. The lack of a gold standard tool that incorporates all proxies and cognitive tests highlights the need to develop a more holistic battery for the quantitative assessment of CR. Further studies should focus on a quantitative methodology that includes all these proxies supported by normative data to improve the use of CR as a valid measure in clinical contexts.

Introdução: A Escala de Avaliação da Doença de Alzheimer – subescala cognitiva (ADAS-Cog) é uma bateria neuropsicológica breve desenvolvida para caracterizar o desempenho cognitivo de doentes com doença de Alzheimer. Avalia as funções tipicamente mais comprometidas na doença de Alzheimer considerando os seguintes domínios cognitivos: memória, orientação, linguagem, praxia e capacidade construtiva. A deteção precoce das alterações cognitivas assim como a sua monitorização são fundamentais para a prática em ambos os contextos clínico e de investigação. O presente estudo tem como objetivos analisar as propriedades psicométricas da versão portuguesa da Escala de Avaliação da Doença de Alzheimer – subescala cognitiva e estabelecer dados normativos para a população portuguesa.Material e Métodos: A versão portuguesa da Escala de Avaliação da Doença de Alzheimer – subescala foi administrada a 223 participantes cognitivamente saudáveis. Todos os participantes foram avaliados com os seguintes instrumentos: Mini-Mental State Examination, Montreal Cognitive Assessment e Inventário de Avaliação Funcional de Adultos e Idosos. Considerou-se como critério para a inclusão no estudo obter um desempenho normal nestas três provas.Resultados: A Escala de Avaliação da Doença de Alzheimer – subescala revelou boas propriedades psicométricas quando utilizada na população portuguesa. A idade demonstrou ser o principal preditor do desempenho na Escala de Avaliação da Doença de Alzheimer – subescala (R2 = 0,123), tendo a escolaridade menor influência (R2 = 0,027). Em conjunto, estas variáveis sociodemográficas explicaram 14,4% da variância na pontuação total da Escala de Avaliação da Doença de Alzheimer – subescala, sendo ambas consideradas na estratificação dos dados normativos para a população portuguesa.Conclusão: A pontuação total média na Escala de Avaliação da Doença de Alzheimer – subescala foi de 6 pontos. Os dados normativos foram estabelecidos de acordo com a idade e escolaridade, sendo estas variáveis sociodemográficas as que mais contribuíram para a predição do desempenho na Escala de Avaliação da Doença de Alzheimer – subescala, explicando 14,4% da variância. Os dados normativos são de extrema importância para o uso adequado desta bateria em Portugal.

Trace elements (TE) homeostasis is crucial in normal brain functioning. Although imbalances have the potential to exacerbate events leading neurodegenerative diseases, few studies have directly addressed the eventual relationships between TE levels in the human body and future cognitive status. The present study aimed to assess how different TE body-levels relate to cognitive decline. This exploratory research included a study-group (RES) of 20 elderly individuals living in two Portuguese geographical areas of interest (Estarreja; Mértola), as well as a 20 subjects neuropsychological control-group (CTR). Participants were neuropsychologically assessed through the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) and the RES group was biomonitored for TE through fingernail analysis. After 5 years, the cognitive assessments were repeated. Analyses of the RES neuropsychological data showed an average decrease of 6.5 and 5.27 points in MMSE and MoCA, respectively, but TE contents in fingernails were generally within the referenced values for non-exposed individuals. Higher levels of Nickel and Selenium significantly predicted lesser cognitive decline within 5 years. Such preliminary results evidence an association between higher contents of these TE and higher cognitive scores at follow-up, suggesting their contribution to the maintenance of cognitive abilities. Future expansion of the present study is needed in order to comprehensively assess the potential benefits of these TE.

Objective: The Alzheimer’s disease assessment scale–Cognitive Subscale (ADAS-Cog) is a battery to assess cognitive performance in Alzheimer’s disease (AD) and was developed according to the core characteristics of cognitive decline in AD: memory, language, praxis, constructive ability, and orientation. The aim of this study was to explore the diagnostic accuracy and discriminative capacity of the ADAS-Cog for Mild Cognitive Impairment (MCI) and AD, using cut-off points for the Portuguese population. Method: The European Portuguese version of the ADAS-Cog was administrated to 650 participants, divided into a control group (n = 210), an MCI group (n = 240), and an AD group (n = 200). The clinical groups fulfilled standard international diagnostic criteria. Controls were healthy cognitive participants actively integrated in the community. The neuropsychological assessment protocol included the ADAS-Cog, the Mini Mental State Examination (MMSE), the Montreal Cognitive Assessment (MoCA), and the Adults and Older Adults Functional Assessment Inventory (IAFAI). Results: The ADAS-Cog revealed good psychometric indicators, and the total scores were significantly different between the three groups (p < .001: Control < MCI < AD). The optimal cut-off points established were: MCI > 9 points (AUC = .835; sensitivity = 58% and specificity = 91%) and AD > 12 points (AUC = .996; sensitivity = 94% and specificity = 98%). Conclusions: Our findings confirmed the capacity of the ADAS-Cog total score to identify cognitive impairment in AD patients, with poor sensitivity for MCI, in a Portuguese cohort.

The Montreal Cognitive Assessment (MoCA) is a brief cognitive screening instrument that is known for its good psychometric properties and sensitivity to detect mild cognitive impairment (MCI). After ten years, it became relevant to update the previous Portuguese normative study due to changes in the population and some limitations present in the study itself. The study sample was composed of 860 cognitively healthy adults, stratified according to verified distribution of the Portuguese population across several sociodemographic variables. All participants completed a neuropsychological assessment battery, in which the MoCA was included. The analysis of the relationships between the sociodemographic variables and the MoCA show that age and educational level had a significant effect on MoCA scores, with educational level being the better predictor. These results foster the consideration of age and educational level in the development of normative data. The present study contributes to a reliable update of the normative data of MoCA. The new age groups and more stratified norms comply with the natural changes on the Portuguese population, providing an increase of power and clinical accuracy. The presented norms consider the cognitive domains subscores, consequently improving the comprehension and utility of the results obtained from the MoCA test.