Juan Silva-Pereyra

Cognitive reserve (CR) refers to the adaptation of cognitive performance to endure brain pathology or the aging process. CR can be categorized into static (education and occupation) or dynamic (leisure and physical activities) proxies. Typically, longitudinal studies assess CR as a composite score at baseline and cognitive performance as a global score. This study aimed to compare the relationship between different CR proxies (static and dynamic) with 9-year domain-specific cognitive trajectories, and the risk of cognitive impairment in older adults. Data from the latest four waves of the Mexican Health and Aging Study (MHAS; n = 3102, baseline mean age = 66.62 years) were used. Mixed effects models were performed with CR as independent variables and cognitive trajectories (verbal memory encoding and retrieval, verbal fluency, constructional praxis, visual attention, and memory) as outcomes. Education and leisure activities were significant positive predictors of all cognitive domains. Physical activities were a positive predictor of verbal fluency and verbal memory encoding only. Occupation was a positive predictor of verbal fluency and visual attention. Logistic regression analysis was performed to assess the relationship between CR and the risk of cognitive impairment, where education (OR: 0.79, 95% CI: 0.76, 0.83), occupational complexity (OR: 0.85, 95% CI: 0.77, 0.95), and leisure activities (OR: 0.96, 95% CI: 0.95, 0.97) were significant protective factors. Increasing the years of education can serve as a preventive strategy to delay the clinical manifestation of cognitive impairment while implementing leisure activities can act as an intervention to promote cognition even in later years.

Background/Objectives: The Montreal Cognitive Assessment (MoCA) is a widely used cognitive screening tool designed to detect cognitive impairment. However, evidence indicates that the original cut-off score of 26 and the one-point correction for low education may not be appropriate across diverse populations. In Latin America, and particularly in Mexico, existing validation studies are scarce and limited by small sample sizes. The objective of this study was to examine the effects of age and education on MoCA performance in Mexican adults and to develop regression-based normative data for more accurate interpretation. Methods: MoCA performance of 2546 cognitively healthy participants aged 18–99 years from two public health institutions in Mexico City was analyzed. Inclusion criteria required preserved cognition, functionality, independence, and absence of conditions directly affecting brain health. The Spanish version 8.1 of the MoCA was administered. Age-adjusted normative values were obtained. Then, regression analyses were applied to generate age- and education-adjusted norms. Results: MoCA total scores correlated negatively with age and positively with education, while sex showed no significant effect. Regression-based norms revealed that identical raw total scores have different normative interpretations depending on age and education. Conclusions: This study provides the first regression-based MoCA norms for Mexican adults, demonstrating that both age and education exert a substantial influence on test performance. These norms enable a more precise, culturally sensitive interpretation than fixed cut-off scores and reduce the risk of misclassification in clinical and research settings.

Las relaciones anafóricas son fundamentales para la comprensión lectora, ya que dan coherencia a los textos. El presente artículo presenta los principales hallazgos reportados en la literatura especializada en el área de la psicolingüística. En las últimas cuatro décadas se han investigado los aspectos que influyen en el procesamiento y comprensión de las anáforas tanto en adultos como en niños. Se ha encontrado que hay varios factores implicados en este proceso tales como elementos gramaticales y conocimientos en general. De allí la importancia de desarrollar habilidades que ayuden a facilitar la comprensión de las anáforas, principalmente en la población infantil. Se requieren más investigaciones que incluyan la medición de la respuesta cerebral para aportar información más detallada sobre cómo se procesan estas estructuras durante la lectura.

Children with learning disorders (LD) perform below average in tests of academic abilities and intelligence. These children also have a significantly abnormal resting-state electroencephalogram (EEG) compared to children with typical development (TD), i.e., an excess of slow brain oscillations such as delta and theta that may be markers of inefficient cognitive processing. We aimed to explore the relationship between the performance in an intelligence test and the resting-state EEG power spectrum of children with LD. Ninety-one children with LD and 45 control children with TD were evaluated with the Wechsler Intelligence Scale for Children 4th Edition (WISC-IV) test of intelligence and a 19-channel EEG during an eyes-closed resting-state condition. The EEG dimensionality was reduced with a principal component analysis that yielded several components representing EEG bands with functional meaning. The first seven EEG components and the intelligence values were analyzed with multiple linear regression and a between-group discriminant analysis. The EEG power spectrum was significantly related to children’s intelligence, predicting 13.1% of the IQ variance. Generalized delta and theta power were inversely related to IQ, whereas frontoparietal gamma activity was directly related. The intelligence test and the resting state EEG had a combined 82.4% success rate to discriminate between children with TD and those with LDs.

Children with learning disorders (LD children) often have heterogeneous cognitive impairments that affect their ability to learn and use basic academic skills. A proposed cause for this variability has been working memory (WM) capacity. Altered patterns of event-related potentials (ERPs) in these children have also been found in the N400 component associated with semantic priming. However, regarding the semantic priming effect in LD children, no distinction has been made for children with varying WM abilities. This study aims to explore the relationship of WM with the brain’s electrophysiological response that underlies semantic priming in LD children that performed a lexical decision task. A total of 40 children (8-10 years old) participated: 28 children with LD and 12 age-matched controls. The ERPs were recorded for each group and analyzed with permutation-based t-tests. The N400 effect was observed only in the control group, and both groups showed a late positive complex (LPC). Permutation-based regression analyses were performed for the results from the LD group using the WISC-IV indices (e.g., Verbal Comprehension and WM) as independent predictors of the ERPs. The Verbal Comprehension Index, but not the WM index, was a significant predictor of the N400 and LPC effects in LD children.

Se ha reportado que la obesidad y el sobrepeso inflaman crónicamente al cerebro, hecho que puede producir muerte neuronal, degeneración de la sustancia blanca, y ulteriormente, influir en un bajo desempeño cognitivo. La obesidad es un factor de riesgo de deterioro cognitivo o, incluso, algunos tipos de demencia durante el envejecimiento. Por lo tanto, es necesario concientizar a los lectores sobre los peligros en su salud física y mental cuando se tiene un estilo de vida que promueve la obesidad y el sobrepeso.

Children with learning disorders (LDs) often have a lower self-concept than their typically developing peers. Neurofeedback (NFB) treatments seem to improve the cognitive and academic performance of these children, but the effects on self-concept have not been studied. In this exploratory study, 34 right-handed children (8–11 y.o.) with LD and delayed electroencephalographic maturation responded to the Piers–Harris Children’s Self-Concept Scale. One group received NFB (n = 20), and another group (n = 14) served as control, which included 9 children treated with sham-NFB and 5 on a waiting-list. A nonparametric permutation approach was used to compare the academic performance and self-concept difference (postscores – prescores) between the NFB and control groups. Given the smaller size of the control subgroups, a comparison of the percent changes between sham-NFB and the waiting-list was performed with the non-overlap of all pairs (NAP) technique. In the NFB group, the scores of reading, math, and global self-concept increased significantly, highlighting the self-concept subdomains of physical appearance, nonanxiety, popularity, and happiness. Additionally, the sham-NFB subgroup showed better outcomes than the waiting-list subgroup, perhaps due to noncontrolled factors. We found improved academic performance and self-concept in children with LDs who received NFB treatment. This study is an important exploratory step in studying a relevant treatment that seems to ameliorate symptoms of LDs such as anxiety and low self-concept.

La cooperación tiene sus costos, pero también sus beneficios. En una tarea de rastreo visual de objetos con tres niveles de dificultad (4, 5 y 6 objetivos a rastrear respectivamente) se comparó el rendimiento de cada individuo en dos condiciones: rendimiento individual vs. rendimiento del individuo como parte de una díada. El propósito del estudio fue explorar si la diferencia en rendimiento entre estas dos condiciones se puede atribuir a la cooperación. Diez estudiantes universitarios respondieron un cuestionario de personalidad de auto informe (Big Five) y realizaron la tarea de rastreo visual de manera individual y como parte de una díada. Las díadas se grabaron en video para identificar las estrategias de comunicación, resolución de problemas y acuerdos en la selección de objetivos. Las díadas mostraron puntajes más altos y tiempos de reacción más lentos en comparación con el rendimiento individual. Los tiempos de reacción más lentos se asociaron positivamente con los intercambios verbales y las estrategias de división del trabajo en la díada. La amabilidad y la extraversión, medidas por el cuestionario de autoinforme, se asociaron positivamente con el acuerdo en la selección de objetivos. La interacción entre los miembros de una díada y sus rasgos de personalidad podrían ser relevantes para comprender la cooperación exitosa y sus costos asociados. Cooperation has its costs but also its benefits. In a Multiple Object Tracking Task with three different levels of difficulty (4, 5, and 6 targets to track, respectively), participants underwent two conditions: solo performance vs performance of the same individual in a dyad. The study's objective was to explore whether the difference in performance between these two conditions is related to cooperation. Ten university students answered a self-report personality questionnaire (Big Five) and performed the visual tracking task. The dyads were recorded on video to identify communication strategies, problem-solving strategies, and target selection agreements. Dyads showed higher scores and slower reaction times compared to solo performance. Slower reaction times were positively associated with verbal exchanges and division of labor strategies. Agreeableness and extraversion, as measured by the self-report questionnaire, were positively associated with agreement on target selection. Interaction between members of a dyad and their personality traits might be relevant for understanding successful cooperation and its costs.

Electroencephalograms (EEGs) of children with reading disorders (RDs) are characterized by a higher theta and a lower alpha than those of typically developing children. Neurofeedback (NFB) may be helpful for treating learning disorders by reinforcing a reduction in the theta/alpha ratio. Several studies have suggested that NFB may lead to EEG power normalization and cognitive improvements. To further explore brain changes in isolated areas, the aim of this study was to explore the effects of an NFB protocol on functional connectivity (coherence) among children with RDs. Twenty children with an RD and an abnormally high theta/alpha ratio underwent 30 NFB sessions, and five children with the same characteristics received a sham NFB treatment. On average, the children in the NFB group showed an increase in reading accuracy and comprehension scores; their coherence diminished in the delta, theta, and beta bands and increased in the alpha band, primarily the theta intrahemispheric coherences of the left hemisphere, which is closely associated with reading. In contrast, children who received the sham NFB treatment did not show reading changes and had few changes in their coherence patterns. These preliminary results suggest that NFB can positively impact reading-related functions in the brain networks of children with RDs.