Advancements in dementia research, diagnostics, and care in Latin America: Highlights from the 2023 Alzheimer's Association International conference satellite symposium in Mexico City.

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.

Behavioural insights (BI) for childhood development and effective public policies in Latin America: a survey and a randomised controlled trial.

OBJECTIVES: We developed (a) a survey to investigate the knowledge of childhood health experts on public policies and behavioural insights (BI), as well as its use in Latin American and the Caribbean countries (LACs), and (b) an intervention (randomised controlled trial) to test the influence of nudges on the effect of a simulated public health programme communication. PARTICIPANTS AND SETTINGS: A total of 2003 LACs childhood health professionals participated in the study through a Hispanic online platform. PRIMARY AND SECONDARY OUTCOMES: We used regression models analysing expertise-related information, individual differences and location. We extracted several outcome variables related to (a) 'Public Policy Knowledge Index' based on the participants' degree of knowledge on childhood health public policies and (b) BI knowledge, perceived effectiveness and usefulness of a simulated public programme communication. We also analysed a 'Behavioural Insights Knowledge Index' (BIKI) based on participants' performance in BI questions. RESULTS: In general, health professionals showed low BI knowledge (knowledge of the term BI: χ2=210.29, df=1 and p<0.001; BIKI: χ2=160.5, df=1 and p<0.001), and results were modulated by different factors (age, academic formation, public policy knowledge and location). The use of BI principles for the communication of the public programme revealed higher impact and clarity ratings from professionals than control messages. CONCLUSIONS: Our findings provide relevant knowledge about BI in health professionals to inform governmental and non-governmental organisations' decision-making processes related with childhood public policies and BI designs.

ERPs studies of cognitive processing during sleep.

In the last few decades, several works on cognitive processing during sleep have emerged. The study of cognitive processing with event related potentials (ERPs) during sleep is a topic of great interest, since ERPs allow the study of stimulation with passive paradigms (without conscious response or behavioural response), opening multiple research possibilities during different sleep phases. We review ERPs modulated by cognitive processes during sleep: N1, Mismatch Negativity (MMN), P2, P3, N400-like, N300-N550, among others. The review shows that there are different cognitive discriminations during sleep related to the frequency, intensity, duration, saliency, novelty, proportion of appearance, meaning, and even sentential integration of stimuli. The fascinating results of cognitive processing during sleep imply serious challenges for cognitive models. The studies of ERPs, together with techniques of neuroimaging, have demonstrated the existence of cognitive processing during sleep. A fundamental question to be considered is if these cognitive phenomena are similar to processing that occurs during wakefulness. Based on this question we discussed the existence of possible mechanisms associated with sleep, as well as the specific cognitive and neurophysiologic differences of wakefulness and sleep. Much knowledge is still required to even understand the conjunction of dramatic changes in cerebral dynamics and the occurrence of cognitive processes. We propose some insights based on ERPs research for further construction of theoretical models for integrating both cognitive processing and specific brain sleep dynamics.

Methodological considerations related to sleep paradigm using event related potentials.

In the last few decades, several works on event related potentials (ERPs hereafter) during sleep have been reported. In spite of numerous studies, clear methodological rules for this kind of study are often missing, making it difficult to valorize the scope of these results. We propose here a description of methodological aspects to be considered when evaluating ERPs during sleep. The use of Rechtschaffen and Kales rules versus automatic methods is assessed, plus the additional use of certain quantitative measures. Additionally, two topics are discussed which must be controlled in ERPs sleep studies: the First Night Effect, and sleep disturbances. Better control of experimental paradigms is relevant for the growth of the neuroscience of sleep.

Contextual social cognition impairments in schizophrenia and bipolar disorder.

BACKGROUND: The ability to integrate contextual information with social cues to generate social meaning is a key aspect of social cognition. It is widely accepted that patients with schizophrenia and bipolar disorders have deficits in social cognition; however, previous studies on these disorders did not use tasks that replicate everyday situations. METHODOLOGY/PRINCIPAL FINDINGS: This study evaluates the performance of patients with schizophrenia and bipolar disorders on social cognition tasks (emotional processing, empathy, and social norms knowledge) that incorporate different levels of contextual dependence and involvement of real-life scenarios. Furthermore, we explored the association between social cognition measures, clinical symptoms and executive functions. Using a logistic regression analysis, we explored whether the involvement of more basic skills in emotional processing predicted performance on empathy tasks. The results showed that both patient groups exhibited deficits in social cognition tasks with greater context sensitivity and involvement of real-life scenarios. These deficits were more severe in schizophrenic than in bipolar patients. Patients did not differ from controls in tasks involving explicit knowledge. Moreover, schizophrenic patients' depression levels were negatively correlated with performance on empathy tasks. CONCLUSIONS/SIGNIFICANCE: Overall performance on emotion recognition predicted performance on intentionality attribution during the more ambiguous situations of the empathy task. These results suggest that social cognition deficits could be related to a general impairment in the capacity to implicitly integrate contextual cues. Important implications for the assessment and treatment of individuals with schizophrenia and bipolar disorders, as well as for neurocognitive models of these pathologies are discussed.

P300 and neuropsychological assessment in mild cognitive impairment and Alzheimer dementia.

Only a small proportion of individuals with Mild Cognitive Impairment (MCI) will convert to dementia. Methods currently available to identify risk for conversion do not combine enough sensitivity and specificity, which is even more problematic in low-educated populations. Current guidelines suggest the use of combined markers for dementia to enhance the prediction accuracy of assessment methods. The present study adhered to this proposal and investigated the sensitivity and specificity of the electrophysiological component P300 and standard neuropsychological tests to assess patients with Alzheimer's disease (AD) and MCI recruited from a low-income country. The neuropsychological battery comprised tests of memory, attention, language, praxis, and executive functions. The P300 was recorded using a classical visual odd-ball paradigm. Three variables were found to achieve sensitivity and specificity values above 80% (Immediate and Delayed recall of word list - CERAD - and the latency of P300) for both MCI and AD. When they entered the model together (i.e., combined approach) the sensitivity for MCI increased to 96% and the specificity remained high (80%). Our preliminary findings suggest that the combined use of sensitive neuropsychological tasks and the analysis of the P300 may offer a very useful method for the preclinical assessment of AD, particularly in populations with low socioeconomic and educational levels. Our results provide a platform and justification to employ more resources to convert P300 and related parameters into a biological marker for AD.

Methodological considerations related to sleep paradigm using event related potentials

In the last few decades, several works on event related potentials (ERPs hereafter) during sleep have been reported. In spite of numerous studies, clear methodological rules for this kind of study are often missing, making it difficult to valorize the scope of these results. We propose here a description of methodological aspects to be considered when evaluating ERPs during sleep. The use of Rechtschaffen and Kales rules versus automatic methods is assessed, plus the additional use of certain quantitative measures. Additionally, two topics are discussed which must be controlled in ERPs sleep studies: the First Night Effect, and sleep disturbances. Better control of experimental paradigms is relevant for the growth of the neuroscience of sleep.