Principles for Adapting Assessments of Executive Function across Cultural Contexts

Direct assessments of executive functions (EFs) are increasingly used in research and clinical settings, with a central assumption that they assess "universal" underlying skills. Their use is spreading globally, raising questions about the cultural appropriateness of assessments devised in Western industrialized countries. We selectively reviewed multidisciplinary evidence and theory to identify sets of cultural preferences that may be at odds with the implicit assumptions of EF assessments. These preferences relate to motivation and compliance; cultural expectations for interpersonal engagement; contextualized vs. academic thinking; cultural notions of speed and time; the willingness to be silly, be incorrect, or do the opposite; and subject-matter familiarity. In each case, we discuss how the cultural preference may be incompatible with the assumptions of assessments, and how future research and practice can address the issue. Many of the cultural preferences discussed differ between interdependent and independent cultures and between schooled and unschooled populations. Adapting testing protocols to these cultural preferences in different contexts will be important for expanding our scientific understanding of EF from the narrow slice of the human population that has participated in the research to date.

Building an assessment of community-defined social-emotional competencies from the ground up in Tanzania

Two studies were conducted in 2017 to investigate children's competencies seen as important by communities in Mtwara, Tanzania. Qualitative data from 95 parents (34 women) and 27 teachers (11 women) in Study 1 indicated that dimensions of social responsibility, such as obedience, were valued highly. In Study 2, the competencies of 477 children (245 girls), aged 4–13 years, were rated by teachers and parents. Factor analysis found the obedient factor explained the most variance in parent rating. In line with predictions, urban residence, parental socioeconomic status (SES), and parental education were all positively associated with ratings of curiosity, and parental SES was negatively associated with obedience and emotional regulation. Findings illustrate the need for culturally specific frameworks of social‐emotional learning.

Preventive malaria treatment among school-aged children in sub-Saharan Africa: a systematic review and meta-analyses

BACKGROUND

The burden of malaria infection in sub-Saharan Africa among school-aged children aged 5-15 years is underappreciated and represents an important source of human-to-mosquito transmission of Plasmodium falciparum. Additional interventions are needed to control and eliminate malaria. We aimed to assess whether preventive treatment of malaria might be an effective means of reducing P falciparum infection and anaemia in school-aged children and lowering parasite transmission.

METHODS

In this systematic review and two meta-analyses, we searched the online databases PubMed, Embase, Cochrane CENTRAL, and Clinicaltrials.gov for intervention studies published between Jan 1, 1990, and Dec 14, 2018. We included randomised studies that assessed the effect of antimalarial treatment among asymptomatic school-aged children aged 5-15 years in sub-Saharan Africa on prevalence of P falciparum infection and anaemia, clinical malaria, and cognitive function. We first extracted data for a study-level meta-analysis, then contacted research groups to request data for an individual participant data meta-analysis. Outcomes of interest included prevalence of P falciparum infection detected by microscopy, anaemia (study defined values or haemoglobin less than age-adjusted and sex-adjusted values), clinical malaria (infection and symptoms on the basis of study-specific definitions) during follow-up, and code transmission test scores. We assessed effects by treatment type and duration of time protected, and explored effect modification by transmission setting. For study-level meta-analysis, we calculated risk ratios for binary outcomes and standardised mean differences for continuous outcomes and pooled outcomes using fixed-effect and random-effects models. We used a hierarchical generalised linear model for meta-analysis of individual participant data. This study is registered with PROSPERO, CRD42016030197.

FINDINGS

Of 628 studies identified, 13 were eligible for the study-level meta-analysis (n=16 309). Researchers from 11 studies contributed data on at least one outcome (n=15 658) for an individual participant data meta-analysis. Interventions and study designs were highly heterogeneous; overall risk of bias was low. In the study-level meta-analysis, treatment was associated with reductions in P falciparum prevalence (risk ratio [RR] 0·27, 95% CI 0·17-0·44), anaemia (0·77, 0·65-0·91), and clinical malaria (0·40, 0·28-0·56); results for cognitive outcomes are not presented because data were only available for three trials. In our individual participant data meta-analysis, we found treatment significantly decreased P falciparum prevalence (adjusted RR [ARR] 0·46, 95% CI 0·40-0·53; p<0·0001; 15 648 individuals; 11 studies), anaemia (ARR 0·85, 0·77-0·92; p<0·0001; 15 026 individuals; 11 studies), and subsequent clinical malaria (ARR 0·50, 0·39-0·60; p<0·0001; 1815 individuals; four studies) across transmission settings. We detected a marginal effect on cognitive function in children older than 10 years (adjusted mean difference in standardised test scores 0·36, 0·01-0·71; p=0·044; 3962 individuals; five studies) although we found no significant effect when combined across all ages.

INTERPRETATION

Preventive treatment of malaria among school-aged children significantly decreases P falciparum prevalence, anaemia, and risk of subsequent clinical malaria across transmission settings. Policy makers and programme managers should consider preventive treatment of malaria to protect this age group and advance the goal of malaria elimination, while weighing these benefits against potential risks of chemoprevention.

FUNDING

US National Institutes of Health and Burroughs Wellcome Fund/ASTMH Fellowship.

Practical lessons for phone-based assessments of learning

School closures affecting more than 1.5 billion children are designed to prevent the spread of current public health risks from the COVID-19 pandemic, but they simultaneously introduce new short-term and long-term health risks through lost education. Measuring these effects in real time is critical to inform effective public health responses, and remote phone-based approaches are one of the only viable options with extreme social distancing in place. However, both the health and education literature are sparse on guidance for phone-based assessments. In this article, we draw on our pilot testing of phone-based assessments in Botswana, along with the existing literature on oral testing of reading and mathematics, to propose a series of preliminary practical lessons to guide researchers and service providers as they try phone-based learning assessments. We provide preliminary evidence that phone-based assessments can accurately capture basic numeracy skills. We provide guidance to help teams (1) ensure that children are not put at risk, (2) test the reliability and validity of phone-based measures, (3) use simple instructions and practice items to ensure the assessment is focused on the target skill, not general language and test-taking skills, (4) adapt the items from oral assessments that will be most effective in phone-based assessments, (5) keep assessments brief while still gathering meaningful learning data, (6) use effective strategies to encourage respondents to pick up the phone, (7) build rapport with adult caregivers and youth respondents, (8) choose the most cost-effective medium and (9) account for potential bias in samples.

Literacy acquisition in multilingual educational contexts: Evidence from Coastal Kenya

Literacy is a powerful tool against poverty, leading to further education and vocational success. In sub-Saharan Africa, schoolchildren commonly learn in two languages-African and European. Multiple early literacy skills (including phonological awareness and receptive language) support literacy acquisition, but this has yet to be empirically tested in sub-Saharan Africa, where learning contexts are highly multilingual, and children are often learning to read in a language they do not speak at home. We use longitudinal data from 1,100 schoolchildren spanning three groups of native languages [Mijikenda languages (Digo, Duruma, Chonyi, and Giriama), Kiswahili, Kikamba] in coastal Kenya (language of instruction: Kiswahili and English). We find that baseline phonological awareness and receptive language are differentially important in predicting literacy skills in English and in Kiswahili, and these relations are moderated by the degree of shared cross-linguistic features between home and school languages. Importantly, the relative importance of these factors changes over development. Implications for language development and literacy acquisition in linguistically diverse contexts are discussed.

Do Schooling and Urban Residence Develop Cognitive Skills at the Expense of Social Responsibility? A Study of Adolescents in the Gambia, West Africa

The recent growth of schooling and urban residence represents a major change to the cultural context of child development across Africa. The aim of this article is to examine the relationship between these social changes in the Gambia and the development of both cognitive skills and behaviors viewed by participant communities as the basis for success in village life, comprising six aspects of social responsibility. We compared these skills and behaviors in a sample of 562 Gambian adolescents ( M age = 17.1 years) from 10 villages who had either attended a government primary school ( n = 207; 36.8%) or a madrasa ( n = 355; 63.2%). A total of 235 participants (41.8%) had spent a short time living in the Gambia’s major urban center (median visit duration of 4.2 months). This temporary urban residence was associated with improved performance in all six cognitive tests and a decrease in five of the six social responsibility scores, as rated by adults in the community. Government schooling was associated with improved performance in five of the six cognitive tests, but there was no consistent relationship with social responsibility ratings. Associations may result from the profiles of young Gambians who choose or who are selected to go to school or live in the city, or they may result from the effects of those environments on their behaviors and skills. In either case, the implications of our findings are that schooling values certain cognitive abilities and urban life values these cognitive abilities too but devalues social responsibility.

Reading and Phonological Awareness in Africa

Literacy levels in Africa are low, and school instruction outcomes are not promising. Africa also has a disproportionate number of unschooled children. Phonological awareness (PA), especially phoneme awareness, is critically associated with literacy, but there is little evidence about whether PA is gained through literacy, schooling, or both, because most children studied are in education and can read at least letters. Our previous study of PA and reading in children in and out of school in Tanzania found that PA was associated with reading ability, not schooling or age, and many unschooled children learned to read. We retested 85 children from the baseline study, on measures of PA and literacy, approximately 2 years later. We found that more unschooled children had now learned to read but PA had generally not improved for these children. Unschooled children were still poorer at PA than schooled children. At 2 years, schooling now independently predicted PA and literacy. PA also predicted literacy and vice versa. Explicit phoneme awareness was again poor, even in accurate readers. More unschooled children have now learned to read, possibly because local literacy is in their first language; however, schooling improves reading and PA.

Early childhood malaria prevention and children's patterns of school leaving in the Gambia

BACKGROUND

Early childhood malaria is often fatal, but its impact on the development and education of survivors has not received much attention. Malaria impacts cognitive development in a number of ways that may impact later educational participation.

AIMS

In this study, we examine the long-term educational effects of preventing early childhood malaria. Does intermittent preventive treatment (IPT) during early childhood reduce the risk of dropout? If so, does this effect vary by school type - government school versus madrassa?

SAMPLE

We use data from a 2001 follow-up of a 1985-1987 malaria prevention randomized controlled trial in the Gambia. The sample consists of 562 youth born between 1981 and 1986.

METHODS

We use discrete-time survival analysis to identify the impact of the intervention on dropout risk over time.

RESULTS

We find that IPT has a positive impact on dropout for government school students, but not for madrassa attendees. The difference was striking: in government schools, the odds of dropout in the treatment group were one third of those in the control group.

CONCLUSIONS

Our findings suggest that preventing early childhood malaria may reduce dropout at a relatively low cost. In this intervention, the drugs cost less than one dollar per year per child. While IPT is no longer practised in many countries due to concerns over drug resistance, these results support the conclusion that any type of effective malaria control programme protecting young children, such as consistent and correct use of bed nets, could improve educational attainment in areas where malaria is prevalent.

Impact of intermittent screening and treatment for malaria among school children in Kenya: a cluster randomised trial

BACKGROUND

Improving the health of school-aged children can yield substantial benefits for cognitive development and educational achievement. However, there is limited experimental evidence of the benefits of alternative school-based malaria interventions or how the impacts of interventions vary according to intensity of malaria transmission. We investigated the effect of intermittent screening and treatment (IST) for malaria on the health and education of school children in an area of low to moderate malaria transmission.

METHODS AND FINDINGS

A cluster randomised trial was implemented with 5,233 children in 101 government primary schools on the south coast of Kenya in 2010-2012. The intervention was delivered to children randomly selected from classes 1 and 5 who were followed up for 24 months. Once a school term, children were screened by public health workers using malaria rapid diagnostic tests (RDTs), and children (with or without malaria symptoms) found to be RDT-positive were treated with a six dose regimen of artemether-lumefantrine (AL). Given the nature of the intervention, the trial was not blinded. The primary outcomes were anaemia and sustained attention. Secondary outcomes were malaria parasitaemia and educational achievement. Data were analysed on an intention-to-treat basis. During the intervention period, an average of 88.3% children in intervention schools were screened at each round, of whom 17.5% were RDT-positive. 80.3% of children in the control and 80.2% in the intervention group were followed-up at 24 months. No impact of the malaria IST intervention was observed for prevalence of anaemia at either 12 or 24 months (adjusted risk ratio [Adj.RR]: 1.03, 95% CI 0.93-1.13, p = 0.621 and Adj.RR: 1.00, 95% CI 0.90-1.11, p = 0.953) respectively, or on prevalence of P. falciparum infection or scores of classroom attention. No effect of IST was observed on educational achievement in the older class, but an apparent negative effect was seen on spelling scores in the younger class at 9 and 24 months and on arithmetic scores at 24 months.

CONCLUSION

In this setting in Kenya, IST as implemented in this study is not effective in improving the health or education of school children. Possible reasons for the absence of an impact are the marked geographical heterogeneity in transmission, the rapid rate of reinfection following AL treatment, the variable reliability of RDTs, and the relative contribution of malaria to the aetiology of anaemia in this setting.

TRIAL REGISTRATION

www.ClinicalTrials.gov NCT00878007.

Cluster-randomised trial of the impact of school-based deworming and iron supplementation on the cognitive abilities of schoolchildren in Sri Lanka's plantation sector

OBJECTIVE

To assess the impact of deworming and iron supplementation on the cognitive abilities and educational achievement of school-age children in Sri Lanka.

METHODS

Prospective, placebo-controlled randomised study. The treatment group received deworming and weekly iron supplementation for 6 months; the control group received placebo for both the anthelmintic and iron. A mixed effects regression model was used to answer the main research question. To increase the precision of this study's estimates, various background variables were controlled for that were not related to treatment but could have some impact on the outcome.

RESULTS

The prevalence of soil-transmitted helminth (STH) infection was reduced in the treatment group (n = 615), with significant differences between treatment and control groups (n = 575) in the levels of Ascaris and Trichuris. No impact was found on haemoglobin (Hb) levels, nor any significant impact on concentration levels or on educational test scores.

CONCLUSION

Decline in STH prevalence alone, in the absence of improved Hb status, produced no evidence of impact on concentration levels or educational test scores.

Challenges for consent and community engagement in the conduct of cluster randomized trial among school children in low income settings: experiences from Kenya

Background

There are a number of practical and ethical issues raised in school-based health research, particularly those related to obtaining consent from parents and assent from children. One approach to developing, strengthening, and supporting appropriate consent and assent processes is through community engagement. To date, much of the literature on community engagement in biomedical research has concentrated on community- or hospital-based research, with little documentation, if any, of community engagement in school-based health research. In this paper we discuss our experiences of consent, assent and community engagement in implementing a large school-based cluster randomized trial in rural Kenya.

Methods

Data collected as part of a qualitative study investigating the acceptability of the main trial, focus group discussions with field staff, observations of practice and authors’ experiences are used to: 1) highlight the challenges faced in obtaining assent/consent; and 2) strategies taken to try to both protect participant rights (including to refuse and to withdraw) and ensure the success of the trial.

Results

Early meetings with national, district and local level stakeholders were important in establishing their co-operation and support for the project. Despite this support, both practical and ethical challenges were encountered during consenting and assenting procedures. Our strategy for addressing these challenges focused on improving communication and understanding of the trial, and maintaining dialogue with all the relevant stakeholders throughout the study period.

Conclusions

A range of stakeholders within and beyond schools play a key role in school based health trials. Community entry and information dissemination strategies need careful planning from the outset, and with on-going consultation and feedback mechanisms established in order to identify and address concerns as they arise. We believe our experiences, and the ethical and practical issues and dilemmas encountered, will be of interest for others planning to conduct school-based research in Africa.

Trial registration

National Institute of Health NCT00878007

Plasmodium falciparum, anaemia and cognitive and educational performance among school children in an area of moderate malaria transmission: baseline results of a cluster randomized trial on the coast of Kenya

OBJECTIVES

Studies have typically investigated health and educational consequences of malaria among school-aged children in areas of high malaria transmission, but few have investigated these issues in moderate transmission settings. This study investigates the patterns of and risks for Plasmodium falciparum and anaemia and their association with cognitive and education outcomes on the Kenyan coast, an area of moderate malaria transmission.

METHODS

As part of a cluster randomised trial, a baseline cross-sectional survey assessed the prevalence of and risk factors for P. falciparum infection and anaemia and the associations between health status and measures of cognition and educational achievement. Results are presented for 2400 randomly selected children who were enrolled in the 51 intervention schools.

RESULTS

The overall prevalence of P. falciparum infection and anaemia was 13.0% and 45.5%, respectively. There was marked heterogeneity in the prevalence of P. falciparum infection by school. In multivariable analysis, being male, younger age, not sleeping under a mosquito net and household crowding were adjusted risk factors for P. falciparum infection, whilst P. falciparum infection, being male and indicators of poor nutritional intake were risk factors for anaemia. No association was observed between either P. falciparum or anaemia and performance on tests of sustained attention, cognition, literacy or numeracy.

CONCLUSION

The results indicate that in this moderate malaria transmission setting, P. falciparum is strongly associated with anaemia, but there is no clear association between health status and education. Intervention studies are underway to investigate whether removing the burden of chronic asymptomatic P. falciparum and related anaemia can improve education outcomes.

The impact of education on sexual behavior in sub-Saharan Africa: a review of the evidence

Many studies have attempted to determine the relationship between education and HIV status. However, a complete and causal understanding of this relationship requires analysis of its mediating pathways, focusing on sexual behaviors. We developed a series of hypotheses based on the differential effect of educational attainment on three sexual behaviors. We tested our predictions in a systematic literature review including 65 articles reporting associations between three specific sexual behaviors -- sexual initiation, number of partners, and condom use -- and educational attainment or school enrollment in sub-Saharan Africa. The patterns of associations varied by behavior. The findings for condom use were particularly convergent; none of the 44 studies using educational attainment as a predictor reviewed found that more educated people were significantly less likely to use condoms. Findings for sexual initiation and number of partners were more complex. The contrast between findings for condom use on the one hand and sexual initiation and number of partners on the other supports predictions based on our theoretical framework.

Causes and consequences of psychological distress among orphans in eastern Zimbabwe

Substantial resources are invested in psychological support for children orphaned or otherwise made vulnerable in the context of HIV/AIDS (OVC). However, there is still only limited scientific evidence for greater psychological distress amongst orphans and even less evidence for the effectiveness of current support strategies. Furthermore, programmes that address established mechanisms through which orphanhood can lead to greater psychological distress should be more effective. We use quantitative and qualitative data from Eastern Zimbabwe to measure the effects of orphanhood on psychological distress and to test mechanisms for greater distress amongst orphans suggested in a recently published theoretical framework.

Orphans were found to suffer greater psychological distress than non-orphans (sex- and age-adjusted co-efficient: 0.15; 95% CI 0.03–0.26; P = 0.013). Effects of orphanhood contributing to their increased levels of distress included trauma, being out-of-school, being cared for by a non-parent, inadequate care, child labour, physical abuse, and stigma and discrimination. Increased mobility and separation from siblings did not contribute to greater psychological distress in this study. Over 40% of orphaned children in the sample lived in households receiving external assistance. However, receipt of assistance was not associated with reduced psychological distress.

These findings and the ideas put forward by children and caregivers in the focus group discussions suggest that community-based programmes that aim to improve caregiver selection, increase support for caregivers, and provide training in parenting responsibilities and skills might help to reduce psychological distress. These programmes should be under-pinned by further efforts to reduce poverty, increase school attendance and support out-of-school youth.

Improving educational achievement and anaemia of school children: design of a cluster randomised trial of school-based malaria prevention and enhanced literacy instruction in Kenya

BACKGROUND

Improving the health of school-aged children can yield substantial benefits for cognitive development and educational achievement. However, there is limited experimental evidence on the benefits of school-based malaria prevention or how health interventions interact with other efforts to improve education quality. This study aims to evaluate the impact of school-based malaria prevention and enhanced literacy instruction on the health and educational achievement of school children in Kenya.

DESIGN

A factorial, cluster randomised trial is being implemented in 101 government primary schools on the coast of Kenya. The interventions are (i) intermittent screening and treatment of malaria in schools by public health workers and (ii) training workshops and support for teachers to promote explicit and systematic literacy instruction. Schools are randomised to one of four groups: receiving either (i) the malaria intervention alone; (ii) the literacy intervention alone; (iii) both interventions combined; or (iv) control group where neither intervention is implemented. Children from classes 1 and 5 are randomly selected and followed up for 24 months. The primary outcomes are educational achievement and anaemia, the hypothesised mediating variables through which education is affected. Secondary outcomes include malaria parasitaemia, school attendance and school performance. A nested process evaluation, using semi-structured interviews, focus group discussion and a stakeholder analysis will investigate the community acceptability, feasibility and cost-effectiveness of the interventions.

DISCUSSION

Across Africa, governments are committed to improve health and education of school-aged children, but seek clear policy and technical guidance as to the optimal approach to address malaria and improved literacy. This evaluation will be one of the first to simultaneously evaluate the impact of health and education interventions in the improvement of educational achievement. Reflection is made on the practical issues encountered in conducting research in schools in Africa.

TRIAL REGISTRATION

National Institutes of Health NCT00878007.

We don't have language at our house: disentangling the relationship between phonological awareness, schooling, and literacy

BACKGROUND

A strong link between phonological awareness (PA) and literacy exists, but the origins of this link are difficult to investigate, since PA skills are hard to test in young, pre-literate children, and many studies neither include such children nor report children's initial literacy levels.

AIMS

To examine PA and literacy in children who are attending or not attending school in rural East Africa.

SAMPLE

One hundred and eight children ages 7-10 years, with no education, or in grade 1 or 2, randomly selected from a community survey of all children in this age group.

METHODS

PA skill, reading, cognitive abilities, and socio-economic status were examined.

RESULTS

Implicit and explicit PA skill with small or large units is related to letter reading ability, and this effect is independent of age, schooling, and cognitive ability. Some PA tasks are performed above chance levels by children who cannot recognize single letters.

CONCLUSIONS

Basic PA develops prior to the attainment of literacy, and learning to read improves PA both quantitatively and qualitatively.

Relationships between anaemia and parasitic infections in Kenyan schoolchildren: a Bayesian hierarchical modelling approach

Anaemia is multi-factorial in origin and disentangling its aetiology remains problematic, with surprisingly few studies investigating the relative contribution of different parasitic infections to anaemia amongst schoolchildren. We report cross-sectional data on haemoglobin, malaria parasitaemia, helminth infection and undernutrition among 1523 schoolchildren enrolled in classes 5 and 6 (aged 10–21 years) in 30 primary schools in western Kenya. Bayesian hierarchical modelling was used to investigate putative relationships. Children infected with Plasmodium falciparum or with a heavy Schistosoma mansoni infection, stunted children and girls were found to have lower haemoglobin concentrations. Children heavily infected with S. mansoni were also more likely to be anaemic compared with uninfected children. This study further highlights the importance of malaria and intestinal schistosomiasis as contributors to reduced haemoglobin levels among schoolchildren and helps guide the implementation of integrated school health programmes in areas of differing parasite transmission.

HIV-associated orphanhood and children's psychosocial distress: theoretical framework tested with data from Zimbabwe

OBJECTIVES

We measured the psychosocial effect of orphanhood in a sub-Saharan African population and evaluated a new framework for understanding the causes and consequences of psychosocial distress among orphans and other vulnerable children.

METHODS

The framework was evaluated using data from 5321 children aged 12 to 17 years who were interviewed in a 2004 national survey in Zimbabwe. We constructed a measure of psychosocial distress using principle components analysis. We used regression analyses to obtain standardized parameter estimates of psychosocial distress and odds ratios of early sexual activity.

RESULTS

Orphans had more psychosocial distress than did nonorphans. For both genders, paternal, maternal, and double orphans exhibited more-severe distress than did nonorphaned, nonvulnerable children. Orphanhood remained associated with psychosocial distress after we controlled for differences in more-proximate determinants. Maternal and paternal orphans were significantly more likely than were nonorphaned, nonvulnerable children to have engaged in sexual activity. These differences were reduced after we controlled for psychosocial distress.

CONCLUSIONS

Orphaned adolescents in Zimbabwe suffer greater psychosocial distress than do nonorphaned, nonvulnerable children, which may lead to increased likelihood of early onset of sexual intercourse and HIV infection. The effect of strategies to provide psychosocial support should be evaluated scientifically.

Long-term impact of malaria chemoprophylaxis on cognitive abilities and educational attainment: follow-up of a controlled trial

Objectives:

We investigated the long-term impact of early childhood malaria prophylaxis on cognitive and educational outcomes.

Design:

This was a household-based cluster-controlled intervention trial.

Setting:

The study was conducted in 15 villages situated between 32 km to the east and 22 km to the west of the town of Farafenni, the Gambia, on the north bank of the River Gambia.

Participants:

A total of 1,190 children aged 3–59 mo took part in the trial. We traced 579 trial participants (291 in the prophylaxis group and 288 in the placebo group) in 2001, when their median age was 17 y 1 mo (range 14 y 9 mo to 19 y 6 mo).

Interventions:

Participants received malaria chemoprophylaxis (dapsone/pyrimethamine) or placebo for between one and three malaria transmission seasons from 1985 to 1987 during the controlled trial. At the end of the trial, prophylaxis was provided for all children under 5 y of age living in the study villages.

Outcome Measures:

The outcome measures were cognitive abilities, school enrolment, and educational attainment (highest grade reached at school).

Results:

There was no significant overall intervention effect on cognitive abilities, but there was a significant interaction between intervention group and the duration of post-trial prophylaxis (p = 0.034), with cognitive ability somewhat higher in the intervention group among children who received no post-trial prophylaxis (treatment effect = 0.2 standard deviations [SD], 95% confidence interval [CI] −0.03 to 0.5) and among children who received less than 1 y of post-trial prophylaxis (treatment effect = 0.4 SD, 95% CI 0.1 to 0.8). The intervention group had higher educational attainment by 0.52 grades (95% CI = −0.041 to 1.089; p = 0.069). School enrolment was similar in the two groups.

Conclusions:

The results are suggestive of a long-term effect of malaria prophylaxis on cognitive function and educational attainment, but confirmatory studies are needed.

Background: The burden of disease and death from malaria is well documented, but little is known about the impact of malaria on the mental development of children and their ability to learn. Evidence from observational studies suggests episodes of malaria are associated with a negative impact on mental processes such as language, memory, and attention. However, there is very little evidence from trials on whether community-level approaches to malaria prevention can improve mental and educational development in children. In a trial conducted in the Gambia between 1985 and 1987, which was reported in The Lancet (21: 1121–1127), young children were allocated either to receive dapsone/pyrimethamine (a commonly used drug for malaria prevention) or placebo, for up to four years. At the end of the trial, the drug was then offered to all children at the study sites. In a follow-up to the original trial, reported here, the researchers then attempted to trace the original trial participants and look at various measures relating to mental development: memory, attention, reasoning, knowledge, language, and level of schooling reached.

What this trial shows: The investigators found no significant differences in mental development scores (memory, attention, reasoning, knowledge, and language) between children who had received malaria prevention during the trial and those who had not, although scores appeared higher for children who received malaria prevention for the longest period. However, they did see a significant difference in schooling level, with children who received malaria prevention during the trial having achieved just over half a grade higher in school.

Strengths and limitations: The original trial methods ensured that the two participant groups were comparable on relevant demographic, household, and educational factors at the start of the trial. Furthermore, the measures used to compare mental development were appropriate, validated for African populations, and then further adapted in the groups being studied. Although only close to half of the original trial participants could be successfully traced, a sample size calculation shows that the follow-up study probably had enough power to detect important effects. However, a major limitation of the study is that once the main trial was complete, all participants were offered malaria prevention with dapsone/pyrimethamine. This limits the extent to which the follow-up study could have detected prevention effects 14 years later, had they existed. The researchers investigated this by doing separate analyses based on how long children spent in the trial. They found a stronger positive effect of malaria prevention on mental development scores for children who spent longer in the trial (and therefore got post-trial prevention for a shorter period of time). This finding supports, but does not conclusively prove, the hypothesis that malaria prevention enhances mental development.

Contribution to the evidence: This study adds data from a well-controlled clinical trial to the body of evidence suggesting that malaria prevention may have beneficial effects on mental and educational development. Very few previous trials have examined this outcome; these results need to be confirmed in future studies specifically designed to test such hypotheses.

Heavy schistosomiasis associated with poor short-term memory and slower reaction times in Tanzanian schoolchildren

Cross-sectional studies of the relationship between helminth infection and cognitive function can be informative in ways that treatment studies cannot. However, interpretation of results of many previous studies has been complicated by the failure to control for many potentially confounding variables. We gave Tanzanian schoolchildren aged 9-14 a battery of 11 cognitive and three educational tests and assessed their level of helminth infection. We also took measurements of an extensive range of potentially confounding or mediating factors such as socioeconomic and educational factors, anthropometric and other biomedical measures. A total of 272 children were moderately or heavily infected with Schistosoma haematobium, hookworm or both helminth species and 117 were uninfected with either species. Multiple regression analyses, controlling for all confounding and mediating variables, revealed that children with a heavy S. haematobium infection had significantly lower scores than uninfected children on two tests of verbal short-term memory and two reaction time tasks. In one of these tests the effect was greatest for children with poor nutritional status. There was no association between infection and educational achievement, nor between moderate infection with either species of helminth and performance on the cognitive tests. We conclude that children with heavy worm burdens and poor nutritional status are most likely to suffer cognitive impairment, and the domains of verbal short-term memory and speed of information processing are those most likely to be affected.