The effect of physical activity on cognition relative to APOE genotype (PAAD-2): study protocol for a phase II randomized control trial

The relationship between executive functions and mathematics achievements in early-grade elementary students

Mathematics, along with reading and writing, is a core academic subject in the school curriculum. The development of mathematical skills is influenced by various cognitive factors, with executive functions (EF) playing a central role. EF, which encompasses working memory, inhibitory control, and cognitive flexibility, is critical for supporting complex cognitive processes required for problem-solving and mathematical reasoning. Research consistently shows that children with stronger EF tend to achieve better academic outcomes, including in mathematics. The goal of the present study was to examine the relationships between the global EF and its three core components - working memory, inhibitory control, and cognitive flexibility - and their impact on mathematics achievement. The sample for this study consisted of 180 children, aged 8-11 years (mean age: 9.6, SD: 1.0 year; 83 girls, 97 boys). EF was assessed using the Yellow-Red test, while mathematics achievement was evaluated based on teachers' evaluations of the child's mathematics performance. The results indicated a statistically significant effect of global EF and its three components on mathematics achievement. Given the potential malleability of EFs, we conclude with recommendations for strategies to enhance EF development at an early school age.

Development of the First WHO Guidelines for Risk Reduction of Cognitive Decline and Dementia: Lessons Learned and Future Directions

The first WHO guidelines for risk reduction of cognitive decline and dementia marked an important milestone in the field of dementia prevention. In this paper, we discuss the evidence reviewed as part of the guidelines development and present the main themes emerged from its synthesis, to inform future research and policies on dementia risk reduction. The role of intervention effect-size; the mismatch between observational and intervention-based evidence; the heterogeneity of evidence among intervention trials; the importance of intervention duration; the role of timing of exposure to a certain risk factor and interventions; the relationship between intervention intensity and response; the link between individual risk factors and specific dementia pathologies; and the need for tailored interventions emerged as the main themes. The interaction and clustering of individual risk factors, including genetics, was identified as the overarching theme. The evidence collected indicates that multidomain approaches targeting simultaneously multiple risk factors and tailored at both individual and population level, are likely to be most effective and feasible in dementia risk reduction. The current status of multidomain intervention trials aimed to cognitive impairment/dementia prevention was also briefly reviewed. Primary results were presented focusing on methodological differences and the potential of design harmonization for improving evidence quality. Since multidomain intervention trials address a condition with slow clinical manifestation—like dementia—in a relatively short time frame, the need for surrogate outcomes was also discussed, with a specific focus on the potential utility of dementia risk scores. Finally, we considered how multidomain intervention could be most effectively implemented in a public health context and the implications world-wide for other non-communicable diseases targeting common risk factors, taking into account the limited evidence in low-middle income countries. In conclusion, the evidence from the first WHO guidelines for risk reduction of cognitive decline and dementia indicated that “one size does not fit all,” and multidomain approaches adaptable to different populations and individuals are likely to be the most effective. Harmonization in trial design, the use of appropriate outcome measures, and sustainability in large at-risk populations in the context of other chronic disorders also emerged as key elements.

APOE Genotype and Alzheimer's Disease: The Influence of Lifestyle and Environmental Factors

Alzheimer's disease (AD) is the most common neurodegenerative disorder with obscure pathogenesis and no disease-modifying therapy to date. AD is multifactorial disease that develops from the complex interplay of genetic factors and environmental exposures. The E4 allele of the gene encoding apolipoprotein E (APOE) is the most common genetic risk factor for AD, whereas the E2 allele acts in a protective manner. A growing amount of epidemiological evidence suggests that several lifestyle habits and environmental factors may interact with APOE alleles to synergistically affect the risk of AD development. Among them, physical exercise, dietary habits including fat intake and ketogenic diet, higher education, traumatic brain injury, cigarette smoking, coffee consumption, alcohol intake, and exposure to pesticides and sunlight have gained increasing attention. Although the current evidence is inconsistent, it seems that younger APOE4 carriers in preclinical stages may benefit mostly from preventive lifestyle interventions, whereas older APOE4 noncarriers with dementia may show the most pronounced effects. The large discrepancies between the epidemiological studies may be attributed to differences in the sample sizes, the demographic characteristics of the participants, including age and sex, the methodological design, and potential related exposures and comorbidities as possible cofounding factors. In this Review, we aim to discuss available evidence of the prominent APOE genotype-environment interactions in regard to cognitive decline with a focus on AD, providing an overview of the current landscape in this field and suggesting future directions.

An innovative protocol for the artificial speech-directed, contactless administration of laboratory-based comprehensive cognitive assessments: PAAD-2 trial management during the COVID-19 pandemic

The COVID-19 pandemic resulted in suspending in-person human subject research across most institutions in the US. Our extensive cognitive assessment for a phase-2 clinical trial, Physical Activity and Alzheimer's Disease-2 (PAAD-2), was also paused in March 2020. It was important to identify strategies to mitigate the risk of COVID-19 transmission during our testing, which initially required substantial human speech and close person-to-person contact for test directions and instant feedback on paper/pencil tests. Given current understanding of the COVID-19 transmission, we dramatically adjusted the testing protocol to minimize the production of speech droplets and allow social distancing while maintaining the integrity of testing. We adopted state-of-the-art speech synthesis and computerization techniques to create an avatar to speak on behalf of the experimenter for all verbal instructions/feedback, used a document camera to observe the paper/pencil tests from the required distances, and automated the testing sequence and timing. This paper aims 1) to describe an innovative laboratory-based cognitive testing protocol for a completely contact-free, computer-speaking, and semi-automated administration; and 2) to evaluate the integrity of the modified protocol (n = 37) compared with the original protocol (n = 32). We have successfully operated the modified protocol since July 2020 with no evidence of COVID-19 transmission during testing, and data support that the modified protocol is robust and captures data identical to the original protocol. This transition of data collection methods has been critical during the pandemic and will be useful in future studies to mitigate the risk of contagious disease transmission and standardize laboratory-based psychological tests. Trial registration: ClinicalTrials.gov NCT03876314. Registered March 15, 2019.

Can Physical Activity Reduce the Risk of Cognitive Decline in Apolipoprotein e4 Carriers? A Systematic Review

Physical activity (PA) reduces the risk of cognitive decline (CD) in the general population. However, little is known about whether the presence of the apolipoprotein E epsilon 4 allele (APOE e4) could modify this beneficial effect. The aim of this systematic review was to analyze and synthetize the scientific evidence related to PA levels and CD risk in cognitively healthy APOE e4 carriers. Four electronic databases were analyzed. Only original articles with longitudinal study design were selected to analyze the relationship between PA and CD in APOE e4 carriers. Five studies were included in the systematic review. All studies except one stated that PA is a protective factor against CD in APOE e4 carriers. Moreover, partial support was found for the hypothesis that a greater amount and intensity of PA are more beneficial in CD prevention. The results support the idea that PA is a protective factor against CD in APOE e4 carriers. Nevertheless, it would be necessary to carry out further studies that would allow these findings to be contrasted.