Dementia in Latin America: Paving the way toward a regional action plan.

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.

Short-term memory binding is insensitive to the socioeconomic status of older adults with and without mild cognitive impairment.

Objective: The Visual Short-Term Memory Binding (VSTMB) Test is a useful tool in the assessment of Alzheimer's disease (AD). Research has suggested that short-term memory binding is insensitive to the sociocultural characteristics of the assessed individuals. Such earlier studies addressed this influence by considering years of education. The current study aims to determine the influence of sociocultural factors via a measure of Socioeconomic Status (SES) which provides a more holistic approach to these common confounders. Methods: A sample of 126 older adults, both with (n = 59) and without (n = 67) amnestic mild cognitive impairment (aMCI), underwent assessment using a neuropsychological protocol including VSTMB test. All participants were classified as either high SES or low SES, employing the Standard Demographic Classification from the European Society for Opinion and Marketing Research. Results: ANOVA/ANCOVA models confirmed that performance of healthy and aMCI participants on traditional neuropsychological tests were sensitive to SES whereas the VSTMB Test was not. The results add to the growing array of evidence suggesting that there are cognitive abilities which are unaffected by socioeconomic factors, regardless of clinical condition. Conclusions: The lack of sensitivity to sociocultural factors previously reported for the VSTMB test is accompanied by a lack of sensitivity to socioeconomic factors thus broadening the scope of this test to aid in the detection of dementia across populations with different backgrounds. Future studies should take these findings forward and explore the potential influences of AD biomarkers (A/T/N) on the association between cognitive functions and demographic variables.

Assessing attentional bias to emotions in adolescent offenders and nonoffenders.

Emotional processing is a cognitive function essential for the interaction of humans with their environment and the development of adaptive behaviors. Adolescent offenders (AOs) express difficulty in cognitive processes linked to emotional processing, which is a response consistently observed during the endogenous (i.e., controlled) control of attention. Less remains understood of the extent to which such atypical responses extend beyond controlled attention and influence exogenous mechanisms (i.e., automatic). This study explores this hypothesis using the recently devised emotional Flanker paradigm. It recruited a group of 39 male AOs and 39 nonoffenders from Barranquilla, Colombia. Assessment consists of an emotional Flanker paradigm administered along with traditional neurocognitive and social cognition tasks. The AOs displayed the well-known attentional bias to threat and a relatively atypical response to emotional targets in which they detected emotions, particularly negative ones, faster than did nonoffenders. Frontal lobe functions account for these effects but not sociodemographic variables nor general cognitive abilities. The results are interpreted in light of evidence suggesting that youngsters with high levels of antisocial behaviors (e.g., callous-unemotional traits) present an enhanced orientation toward distressing stimuli, which is explained by lifelong experiences (e.g., histories of abuse). The findings suggest that environmental influences seemingly exist in the development of these traits, but additional research is required to elucidate the role of cognitive and environmental factors in the development of antisocial behavior.

Prevalence of Mild Cognitive Impairment in Southern Regions of Colombia.

Background: Recent reports suggest that by 2050 there will be an increase of around 310% of cases affected by dementia in Latin American countries. A previous study in a Southern region reported one of the highest prevalences of dementia in Latin America. Objective: To investigate the prevalence of mild cognitive impairment associated with low education, rurality, and demographic characteristics. Methods: A cross-sectional study recruited a community-dwelling sample of 823 adults from rural and urban areas of two Southern provinces of Colombia from 2020-2022. Participants were assessed with a neuropsychological protocol validated in Colombia. To obtain general and region-specific prevalence rates, age, sex, schooling, and socioeconomic level were considered and controlled for. Results: Most of the participants reported low education and socioeconomic level, the participation of women was higher. It was determined that the prevalence of mild cognitive impairment (MCI) was 53.6%, with 56.6% in the province of Caquetá followed by 51.9% in the province of Huila. The amnestic MCI represented 42.6%, the amnestic multi-domain was 39%, the non-amnestic 16.55%, and the non-amnestic multi-domain 1.81%. Our participants reported comorbidities such as diabetes and hypertension. We also observed a relationship between exposure to pesticides and MCI. Conclusions: We observed one of the highest prevalences of MCI in Latin America reported to date. Variables such as age, gender, and education proved risk factors for MCI in the explored regions. Our findings are very much in line with recent studies that highlight the influence of non-canonical risk factors of dementia in underrepresented countries from Latin America.

Disrupted Spatiotemporal Complexity of Resting-State Electroencephalogram Dynamics Is Associated With Adaptive and Maladaptive Rumination in Major Depressive Disorder.

Patients with major depressive disorder (MDD) exhibit abnormal rumination, including both adaptive and maladaptive forms. However, the neural substrates of rumination in depression remain poorly understood. We hypothesize that divergent spatiotemporal complexity of brain oscillations would be associated with the levels of rumination in MDD. We employed the multi-scale entropy (MSE), power and phase-amplitude coupling (PAC) to estimate the complexity of rhythmic dynamics from the eye-closed high-density electroencephalographic (EEG) data in treatment-naive patients with MDD (n = 24) and healthy controls (n = 22). The depressive, brooding, and reflective subscales of the Ruminative Response Scale were assessed. MDD patients showed higher MSE in timescales finer than 5 (cluster P = 0.038) and gamma power (cluster P = 0.034), as well as lower PAC values between alpha/low beta and gamma bands (cluster P = 0.002- 0.021). Higher reflective rumination in MDD was region-specifically associated with the more localized EEG dynamics, including the greater MSE in scales finer than 8 (cluster P = 0.008), power in gamma (cluster P = 0.018) and PAC in low beta-gamma (cluster P = 0.042), as well as weaker alpha-gamma PAC (cluster P = 0.016- 0.029). Besides, the depressive and brooding rumination in MDD showed the lack of correlations with global long-range EEG variables. Our findings support the disturbed neural communications and point to the spatial reorganization of brain networks in a timescale-dependent migration toward local during adaptive and maladaptive rumination in MDD. These findings may provide potential implications on probing and modulating dynamic neuronal fluctuations during the rumination in depression.

The striatum, the hippocampus, and short-term memory binding: Volumetric analysis of the subcortical grey matter's role in mild cognitive impairment.

BACKGROUND: Deficits in short-term memory (STM) binding are a distinguishing feature of preclinical stages leading to Alzheimer's disease (AD). However, the neuroanatomical correlates of conjunctive STM binding are largely unexplored. Here we examine the possible association between the volumes of hippocampi, parahippocampal gyri, and grey matter within the subcortical structures - all found to have foci that seemingly correlate with basic daily living activities in AD patients - with cognitive tests related to conjunctive STM binding. MATERIALS AND METHODS: Hippocampal, thalamic, parahippocampal and corpus striatum volumes were semi-automatically quantified in brain magnetic resonance images from 25 cognitively normal people and 21 patients with Mild Cognitive Impairment (MCI) at high risk of AD progression, who undertook a battery of cognitive tests and the short-term memory binding test. Associations were assessed using linear regression models and group differences were assessed using the Mann-Whitney U test. RESULTS: Hippocampal and parahippocampal gyrus volumes differed between MCI and control groups. Although the grey matter volume in the globus pallidus (r = -0.71, p < 0.001) and parahippocampal gyry (r = -0.63, p < 0.05) correlated with a STM binding task in the MCI group, only the former remained associated with STM binding deficits in MCI patients, after correcting for age, gender and years of education (ß = -0.56,P = 0.042) although with borderline significance. CONCLUSIONS: Loss of hippocampal volume plays no role in the processing of STM binding. Structures within the basal ganglia, namely the globus pallidus, could be part of the extrahippocampal network supporting binding. Replication of this study in large samples is now needed.

Free Recall of Bound Information Held in Short-Term Memory is Unimpaired by Age and Education.

OBJECTIVES: It has been challenging to identify cognitive markers to differentiate healthy brain aging from neurodegeneration due to Alzheimer's disease (AD) that are not affected by age and education. The Short-Term Memory Binding (STMB) showed not to be affected by age or education when using the change detection paradigm. However, no previous study has tested the effect of age and education using the free recall paradigm of the STMB. Therefore, the objective of this study was to investigate age and education effects on the free recall version of the STMB test under different memory loads. METHODS: 126 healthy volunteers completed the free recall STMB test. The sample was divided into five age bands and into five education bands for comparisons. The STMB test assessed free recall of two (or three) common objects and two (or three) primary colors presented as individual features (unbound) or integrated into unified objects (bound). RESULTS: The binding condition and the larger set size generated lower free recall scores. Performance was lower in older and less educated participants. Critically, neither age nor education modified these effects when compared across experimental conditions (unbound v. bound features). CONCLUSIONS: Binding in short-term memory carries a cost in performance. Age and education do not affect such a binding cost within a memory recall paradigm. These findings suggest that this paradigm is a suitable cognitive marker to differentiate healthy brain aging from age-related disease such as AD.

Overcoming barriers in cognitive assessment of Alzheimer's disease.

Diagnosis of Alzheimer's disease (AD) requires a reliable neuropsychological assessment, but major barriers are still encountered when such tests are used across cultures and during the lifespan. This is particularly problematic in developing countries where most of the available assessment tools have been adapted from developed countries. This represents a major limitation as these tests, although properly translated, may not embody the wealth of challenges that a particular culture poses on cognition. This paper centers on two shortcomings of available cognitive tests for AD, namely, their sensitivity to the educational background and to the age of the individual assessed.

O diagnóstico da doença de Alzheimer (DA) necessita de uma avaliação neuropsicológica de confiança, barreiras importantes ainda são encontradas quando esses testes são usados em através de culturas e durante a vida. Isto é particularmente problemático em países em desenvolvimento, onde a maioria das ferramentas de avaliação disponíveis foram adaptadas a partir de países desenvolvidos. Isto representa uma grande limitação, pois mesmo devidamente traduzidas, podem não pode capturar a riqueza de desafios que uma determinada cultura representa na cognição. Neste artigo vou me concentrar em duas falhas de testes cognitivos disponíveis para AD, sensibilidade ao nível educacional e idade do indivíduo avaliado.

Overcoming barriers in cognitive assessment of Alzheimers disease / Superando barreiras na avaliação cognitiva da doença de Alzheimer

Diagnosis of Alzheimer's disease (AD) requires a reliable neuropsychological assessment, but major barriers are still encountered when such tests are used across cultures and during the lifespan. This is particularly problematic in developing countries where most of the available assessment tools have been adapted from developed countries. This represents a major limitation as these tests, although properly translated, may not embody the wealth of challenges that a particular culture poses on cognition. This paper centers on two shortcomings of available cognitive tests for AD, namely, their sensitivity to the educational background and to the age of the individual assessed.

O diagnóstico da doença de Alzheimer (DA) necessita de uma avaliação neuropsicológica de confiança, barreiras importantes ainda são encontradas quando esses testes são usados em através de culturas e durante a vida. Isto é particularmente problemático em países em desenvolvimento, onde a maioria das ferramentas de avaliação disponíveis foram adaptadas a partir de países desenvolvidos. Isto representa uma grande limitação, pois mesmo devidamente traduzidas, podem não pode capturar a riqueza de desafios que uma determinada cultura representa na cognição. Neste artigo vou me concentrar em duas falhas de testes cognitivos disponíveis para AD, sensibilidade ao nível educacional e idade do indivíduo avaliado.

Método para el estudio de los movimientos oculares / Study method of the eye movements

Introducción: El análisis cuantitativo de los movimientos oculares en el dominio digital ha permitido incrementar la cantidad de información fisiológica que se puede extraer durante la interpretación de las señales oculográficas. En el terreno de las neurociencias, esto posibilita profundizar en el estudio de los mecanismos fisiopatológicos responsables de las afecciones oculomotoras. Objetivos: La finalidad de estos métodos de análisis es reducir el componente subjetivo que se introduce durante la clasificación visual de registros de actividad eléctrica, reduciendo además la experiencia requerida para hacer una correcta evaluación de patrones funcionales. Material y métodos: En el presente trabajo, se estudió la respuesta de persecución visual en 27 sujetos normales aplicando métodos de análisis cuantitativo tanto en el dominio del tiempo como en el dominio de la frecuencia. Se determinó un conjunto de variables que actúa como descriptores cuantitativos de la ejecución oculomotora durante tareas que activan al sistema motor ocular. Resultados: Demuestran que las variables estudiadas en ambos dominios pueden ser de gran utilidad para incrementar el conocimiento de los mecanismos subyacentes a la ejecución oculomotora. La cantidad de información extraída por estos métodos, supera 80/100 del total de la posible a extraer. Conclusiones: Se deben dirigir estudios posteriores para evaluar el comportamiento de estas variables en afecciones del sistema nervioso donde el sistema motor ocular muestre algún grado de compromiso funcional