Contrasting speed and accuracy approaches to measure executive functions in three low-and middle-income countries.

Executive functions (EF) can be measured by tests assessing accuracy, reaction times and by computing scores which combine these two components. Interpretation issues can arise from the use of different scoring methods across studies. Given that EF measures and their scoring methods are predominantly developed and validated in high income countries, little is known about the generalisability of such methods cross- culturally. The current paper compares two different established scoring approaches for measures of inhibition and cognitive flexibility: difference scores (which utilise reaction time only) and computed scores (combining accuracy and reaction time). We utilised data collected in adulthood from three low- and middle-income birth cohorts (Guatemala, Philippines, South Africa). Non-normal distributions were observed for both scoring methods in all three samples; however, this was more pronounced for the difference score method. Differing distribution patterns were observed across the three cohorts, which was especially evident in the Guatemala cohort, highlighting potential issues with using these methods across diverse populations. The data suggest that the computed scores may be a reliable measure of EF. However, the different ways of scoring and interpreting EF instruments need to be considered carefully for each population before use.

Cognitive and socio-emotional correlates of psychological well-being and mental health in Guatemalan adults.

BACKGROUND: Little is known about associations of psychological and mental well-being with cognitive and socioemotional factors in low and middle-income countries, particularly among vulnerable populations born in adverse environments that may restrict developmental potential. This study aimed to examine the cognitive and socioemotional correlates of psychological well-being and mental health in a cohort of Guatemalan adults born in contexts of poverty and malnutrition. METHODS: From Dec 2017 to Apr 2019, data were collected from 704 women and 564 men ages 40-57 years living in four rural villages in eastern Guatemala and Guatemala City. We measured latent domains of psychological well-being, spirituality and religion, emotional support, and executive function using Confirmatory Factor Analysis (CFA). Under a Structural Equation Modeling framework, we examined intercorrelations among latent domains and observed measures of intelligence and mental health. RESULTS: CFA supported the construct validity of factor structures in this population. Correlations of psychological well-being with spirituality and religion were moderate in women (r = 0.68, p < 0.001) and men (r = 0.70, p < 0.001). Executive function was weakly correlated with psychological well-being in men (r = 0.23, p < 0.001) and showed no association in women. Correlations of psychological well-being with emotional support and IQ were weak in women (r = 0.34, and r = 0.15, respectively; p < 0.001 for both) and men (r = 0.35, and r = 0.25, respectively; p < 0.001 for both). Mental health and IQ were weakly correlated in men (r = 0.09, p < 0.05) and showed no association in women. Mental health showed weak correlations with emotional support (r = 0.18, p < 0.001 in women; r = 0.09, p < 0.05 in men), psychological well-being (r = 0.32 and r = 0.35, in women and men respectively; p < 0.001 for both) and showed no association with executive function in both sexes. CONCLUSIONS: Of all examined factors, spirituality and religion made the greatest contribution to psychological well-being. These findings support the notion that in populations experiencing difficult circumstances, religion can perhaps make a greater contribution to well-being and aid coping. More research is needed to examine mediators of this association.

Association between early child development trajectories and adult cognitive function in a 50-year longitudinal study in Guatemala.

OBJECTIVES: Few studies have used longitudinal data to study the development of cognition over the life course in low-income and middle-income countries. The objectives of this study were to assess predictors of cognitive development trajectories from 6 months through 7 years, and if these trajectories predicted adult cognitive function in a birth cohort from Guatemala. DESIGN: We analysed data from the INCAP Nutrition Supplementation Trial Longitudinal Study in Guatemala. Cognition was assessed at eight different time points between 6 months and 7 years. We derived childhood development trajectories using latent class growth analysis. We assessed predictors of the trajectories using ordinal logistic regression, and associations between childhood trajectories and adult non-verbal intelligence and literacy at age 18-52 years (mean±SD =42.7±6.4 years) using mixed models. SETTING: The study was conducted in four Guatemalan villages. PARTICIPANTS: The study included 927 participants from Guatemala with repeated measurements of cognitive function during the first 7 years of life. RESULTS: We identified three trajectories of cognitive development (high: n=214, average: n=583, low: n=130). Participants whose mothers were taller (proportional log odds (PO)=0.03, 95% CI=0.01 to 0.06), had more years of schooling (PO=0.15, 95% CI=0.06 to 0.25), or lived in households with higher socioeconomic scores (PO=0.19, 95% CI=0.09 to 0.29) were more likely to follow higher trajectories. Childhood trajectories predicted adult non-verbal intelligence (high=18.4±0.3, average=14.6±0.53, low=11.4±0.9) and literacy (high=63.8±2.0, average=48.6±1.2, low=33.9± 2.6) scores. CONCLUSIONS: In this sample from Guatemala, cognitive development trajectories from 6 months through 7 years were associated with adult non-verbal intelligence and literacy. These findings provide evidence of tracking of cognition over time in a transitioning low-income setting.

Executive functions form a single construct and are associated with schooling: Evidence from three low- and middle- income countries.

Measuring executive function (EF) among adults is important, as the cognitive processes involved in EF are critical to academic achievement, job success and mental health. Current evidence on measurement and structure of EF largely come from Western, Educated, Industrialized, Rich and Democratic (WEIRD) countries. However, measuring EF in low-and-middle-income countries (LMICs) is challenging, because of the dearth of EF measures validated across LMICs, particularly measures that do not require extensive training, expensive equipment, or professional administration. This paper uses data from three LMIC cohorts to test the feasibility, validity and reliability of EF assessment in adults using three sub-tests (representing key components of EF) of the NIH Toolbox Cognitive battery. For each cohort, all three EF measures (inhibition, flexibility and working memory) loaded well onto a unidimensional latent factor of EF. Factor scores related well to measures of fluid intelligence, processing speed and schooling. All measures showed good test-retest reliability across countries. This study provides evidence for a set of sound measures of EF that could be used across different cultural, language and socio-economic backgrounds in future LMIC research. Furthermore, our findings extend conclusions on the structure of EF beyond those drawn from WEIRD countries.

Early Childhood Nutrition and Cognitive Functioning in Childhood and Adolescence.

BACKGROUND: The Institute of Nutrition of Central America and Panama (INCAP) Longitudinal Study provides a unique opportunity to examine the role of nutrition in cognitive functioning over time, controlling for other sociocultural factors. OBJECTIVE: This article describes results of analyses carried out in the INCAP Longitudinal Study on relationships between early childhood nutritional status and supplementation with concurrent and subsequent cognitive development in childhood and adolescence/young adulthood. METHODS: Articles were chosen for review that addressed this topic from the original and 1988 follow-up studies; 41 articles were reviewed and key results summarized for relationships between early nutrition and cognition in infancy, early childhood, and adolescence/young adulthood. RESULTS: Overall, results suggest strong relationships between indicators of a child's early nutritional status and motor and cognitive development in infancy and through the preschool years, continuing into adolescence/young adulthood, particularly for males. Nutritional supplementation during gestation through 2 years of age was associated with improvements in motor development and small, but consistent improvements in cognitive development during infancy and preschool years, with similar results of greater magnitude found with cognitive functioning in adolescence and young adulthood. Findings remain strong after controlling for various sociocultural factors (eg, socioeconomic status [SES]) and schooling. Among adolescents, significant interactions were found with SES and years of school attained; differences in performance favored Atole over Fresco children, with greatest differences for participants of low SES and those with higher levels of schooling. CONCLUSIONS: Results support the need for programs to address unmet nutritional requirements among at-risk mothers and children and potential beneficial effects for human cognitive development.