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.

The Effects of Multiple Micronutrient Fortified Beverage and Responsive Caregiving Interventions on Early Childhood Development, Hemoglobin, and Ferritin among Infants in Rural Guatemala.

Undernutrition and a lack of learning opportunities can jeopardize long-term growth and development among infants in low- and middle-income countries. We conducted a 6-month 2 × 2 cluster-randomized trial to assess the effects of multiple micronutrient-fortified beverages and responsive caregiving interventions among infants 6-18 months in 72 community sectors in southwest Guatemala. We administered baseline and endline assessments of childhood development (Bayley Scales of Infant and Toddler Development) and socioemotional development (Brief Infant Toddler Socio-Emotional Assessment) and measured ferritin and hemoglobin on a subsample. The trial was analyzed using linear mixed models. At the baseline, the mean age (SD) was 13.0 (4.6) months, including 49% males, 32% who were stunted, 55% who were anemic, and 58% who were iron deficient. At the endline (n = 328/386, 85% retention), there was no synergistic effect on the fortified beverage and responsive caregiving intervention. Compared to the non-fortified beverage group, socioemotional development improved in the fortified beverage group. There were no intervention effects on other measures of child development, hemoglobin, or ferritin. In a setting with high rates of anemia and iron deficiency, a multiple micronutrient-fortified beverage improved infants' socioemotional development.