Factors affecting the cognitive profile of 11-year-old children born very preterm

Finnish children born very preterm have good reading comprehension but weak reading fluency at age 11 years - a longitudinal cohort study

Children born very preterm (<32 gestational weeks and/or birth weight ≤1500 g) are at elevated risk for reading difficulties. This study aimed to investigate reading fluency and reading comprehension at 11 and to analyze the associations between literacy skills at 7 and reading skills at 11 in 134 Finnish-speaking very preterm children. At 11, reading fluency and reading comprehension were evaluated. At 7, pre-reading skills, decoding, and writing were assessed. Results showed that there were more preterm children with weak skills in reading fluency compared to a normative test population. Reading comprehension was age appropriate. Additionally, 62% to 68% of the children with weak literacy skills at 7 had weak reading fluency at 11, compared to those with more advanced skills (43% to 33%, p < 0.001 to 0.026). Respectively, 30% to 50% of the children with weak literacy at 7 had weak reading comprehension at 11 compared to those with more advanced skills (13% to 17%, p < 0.001 to 0.005). Findings highlight the importance of screening reading fluency until 11 years and providing support for the continuum between literacy skills in the beginning of schooling and reading outcome at later school age.

Association between working memory performance and parent and teacher ratings of working memory in 11-year-old children born preterm

Working memory (WM) difficulties are often observed in children born preterm. We examined whether performance-based measures of WM components are associated with parent- and teacher-rated WM difficulties in the everyday life of children born very preterm and/or at very low birth weight (VPT/VLBW) at 11 years (n = 165). The WM components as defined in the original Baddeley's model - phonological loop (PL), visuospatial sketchpad (VS), and central executive (CE) - were assessed with tasks from the Working Memory Test Battery for Children (WMTB-C) and the Wechsler Intelligence Scale for Children - Fourth edition (WISC-IV). Parents and teachers completed the WM subscale of the Behavioral Rating Inventory for Executive Functions (BRIEF). Measures of WM components were modestly associated with BRIEF scores, explaining 18.9% of the variance in parent-rated and 14.0% of teacher-rated WM difficulties. CE was the component most consistently associated with parent- and teacher-rated everyday WM. To conclude, our results suggest that tasks that utilize CE functions may best reflect WM outside of controlled test settings in the follow-up of VPT/VLBW children. However, performance and rating-scale measures provide unique information and are both needed to comprehensively assess WM skills.

Associations between the aetiology of preterm birth and mortality and neurodevelopment up to 11 years

AIM

To investigate how the aetiology of very preterm birth/very low birth weight is associated with mortality and later neurodevelopmental outcomes.

METHODS

Very preterm/very low-birth weight singletons were categorised based on the aetiology of preterm birth: spontaneous preterm birth (n = 47, 28.1%), preterm premature rupture of membranes (n = 56, 33.5%) or placental vascular pathology (n = 64, 38.3%). Mortality, cerebral palsy, severe cognitive impairment by 11 years of age (<2SD) and mean full-scale intelligence quotient at 11 years were studied in association with birth aetiology.

RESULTS

There was no difference in mortality or rate of cerebral palsy according to birth aetiologies. The rate of severe cognitive impairment was lower (4.9% vs. 15.3%) in the preterm premature rupture of the membrane group in comparison to the placental vascular pathology group (OR 0.2, 95% CI 0.03-0.9, adjusted for gestational age). At 11 years, there was no statistically significant difference in the mean full-scale intelligence quotient.

CONCLUSION

Placental vascular pathology, as the aetiology of very preterm birth/very low birth weight, is associated with a higher rate of severe cognitive impairments in comparison to preterm premature rupture of membranes, although there was no difference in the mean full-scale intelligence quotient at 11 years. The aetiology of very preterm birth/very low birth weight was not associated with mortality or the rate of cerebral palsy.

Intelligence Quotient (IQ) in school-aged preterm infants: A systematic review

Preterm birth (before 37 weeks of gestational age) is associated with certain risks to child development. The aim of this systematic review was to summarize available and updated empirical evidence on prematurity as a risk factor for cognitive development in school age. Thus, we attempted to identify similarities and differences with the full-term population and to point out possible risk or protective factors among the biological, psychosocial and family variables. The conceptualization and methodology of this review followed the PRISMA recommendations. The search was carried out in Web of Science, Scopus, PsycInfo, and Dialnet databases, in May 2022. The search was limited to journal articles, published between 2012 and 2022, in English and Spanish. Research articles selected were those focused on the intelligence quotient (IQ) of preterm children aged 6-12 years. The review included studies with cross-sectional or longitudinal cohorts, compared to a control group of children born at term or to standardized scales. The quality of evidence of the selected studies was verified with the Mixed Methods Appraisal Tool (MMAT). The initial search identified 1,040 articles. Forty articles met the inclusion criteria and were finally included in this review. These studies involved 5,396 preterm children from 37 different cohorts. Despite the diversity found among the results, in general, total IQ scores were within the normative mean for premature children; however, compared to their full-term peers, these scores were lower. The most studied variables in relation to IQ are perinatal (e.g., gestational age and birth weight) and family (e.g., socioeconomic level and education level of the mother). Recent studies corroborate that premature birth affects cognitive development in school age, and identify associated perinatal and family variables.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=337371; identifier: CRD42022337371.

Effect of biomedical complications on very and extremely preterm children's language

Introduction

Very and extremely preterm children have been found to show delays in the development of language in early years. In some investigations, however, a rigorous control of biomedical complications, such as Periventricular Leukomalacia (PVL), Intraventricular Hemorrhage (IVH) or Bronchopulmonary Dysplasia (BPD), does not always exist. For that reason, a confounding effect of low gestational age and biomedical complications may lead to erroneous conclusions about the effect of gestational age.

Methods

In this investigation we compare language development [use of words, sentence complexity and mean length of the three longest utterances (MLU3)] of three groups of Chilean children at 24 months of age (corrected age for preterm children). The first group was composed of 42 healthy full-term children (Full term group: FT), the second group of 60 preterm children born below 32 gestational weeks without medical complications (low risk preterm group: LRPT), and the third group was composed of 64 children below 32 gestational weeks who had medical complications (High risk preterm group: HRPT). The three groups were similar in terms of gender distribution, maternal education, and socio-economic environment. The instrument used to assess language was the Communicative Development Inventories (CDI). In addition, the Ages and Stages Questionnaire-3 (ASQ-3) was also used to assess other developmental dimensions.

Results

The results indicate that HRPT and LRPT children obtained significantly lower results than the FT group in the three language measures obtained through the CDI. No significant differences were observed between the HRPT and the LRPT groups, although the HRPT obtained the lowest results in the three CDI measures. The results obtained through the administration of the ASQ-3 confirm the delay of both preterm groups in communicative development when compared to the FT group. No significant differences between the FT and the PT groups were observed in gross motor, fine motor and problem solving dimensions of the ASQ-3. The LRPT group obtained results that were significantly higher than those of the FT group and the HRPT group in gross motor development.

Discussion

These results seem to indicate that the area of language development is particularly influenced by very or extremely low gestational age.

Peripapillary retinal nerve fibre layer thickness and macular ganglion cell layer volume in association with motor and cognitive outcomes in 11-year-old children born very preterm

PURPOSE

The purpose of the study was to study the association between retinal parameters and motor and cognitive outcomes in children born very preterm.

METHODS

This study is part of a prospective cohort study of very preterm infants (birth weight ≤ 1500 grams/gestational age < 32 weeks). At 11 years of age, the ophthalmological assessment included a retinal optical coherence tomography (OCT) examination of the peripapillary retinal nerve fibre layer (PRNFL) and the macular ganglion cell layer (GCL). The motor performance was assessed with the Movement Assessment Battery for Children-Second Edition (Movement ABC-2), and the cognitive outcome with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV).

RESULTS

A total of 141 children were included. The mean (SD) average PRNFL was 95 μm (10.2 μm). The mean (SD) macular GCL volume was 0.34 mm³ (0.03 mm³ ). Higher PRNFL thickness associated with higher percentiles for total scores in the motor assessment (b = 0.5, 95% CI 0.1-0.8, p = 0.01) and higher macular GCL volume with higher scores in the cognitive assessment (b = 1.4, 95% CI 0.5-2.3, p = 0.002), also when adjusted for gender, birth weight z-score (birth weight in relation to gestational age) and major brain pathology at term.

CONCLUSION

The associations between higher average PRNFL thickness and better motor performance as well as higher macular GCL volume and better cognitive performance refer to more generalized changes in the brain of 11-year-old children born very preterm. Retinal OCT examinations might provide a deeper insight than mere eyesight in long-term neurodevelopmental follow-up of children born very preterm.

Mathematical skills of 11-year-old children born very preterm and full-term

Preterm birth affects the academic development of children, especially in mathematics. Remarkably, only a few studies have measured specific effects of preterm birth on mathematical skills in primary school. The aim of this study was to compare 11-year-old children, with an IQ above 70, born very preterm (N = 64) and full-term (N = 72) on a variety of 5th grade mathematical skills and cognitive abilities important for mathematical learning. The measures were spontaneous focusing on numerosity (SFON), spontaneous focusing on quantitative relations (SFOR), arithmetic fluency, mathematics achievement, number line estimation, rational number magnitude knowledge, mathematics motivation, reading skills, visuospatial processing, executive functions, and naming speed. The children born very preterm and full-term differed in arithmetic fluency, SFON and SFOR. Domain general cognitive abilities did not fully explain the group differences in SFON and SFOR. Retrospective comparisons of the samples at the age of five years showed large group differences in early mathematical skills and cognitive abilities. Despite lower early mathematical skills, the children born very preterm reached peer equivalent performance in many mathematical skills by the age of 11 years. Nevertheless, they appear less likely to focus on implicit mathematical features in their everyday life.

Maternal education and cognitive development in 15 European very-preterm birth cohorts from the RECAP Preterm platform

BACKGROUND

Studies are sparse and inconclusive about the association between maternal education and cognitive development among children born very preterm (VPT). Although this association is well established in the general population, questions remain about its magnitude among children born VPT whose risks of medical and developmental complications are high. We investigated the association of maternal education with cognitive outcomes in European VPT birth cohorts.

METHODS

We used harmonized aggregated data from 15 population-based cohorts of children born at <32 weeks of gestational age (GA) or <1500 g from 1985 to 2013 in 13 countries with information on maternal education and assessments of general development at 2-3 years and/or intelligence quotients between 4 and 15 years. Term-born controls (≥37 weeks of GA) were available in eight cohorts. Maternal education was classified as: low (primary/lower secondary); medium (upper secondary/short tertiary); high (bachelor's/higher). Pooled standardized mean differences (SMDs) in cognitive scores were estimated (reference: high educational level) for children assessed at ages 2-3, 4-7 and 8-15 years.

RESULTS

The study included 10 145 VPT children from 12 cohorts at 2-3 years, 8829 from 12 cohorts at 4-7 years and 1865 children from 6 cohorts at 8-15 years. Children whose mothers had low, compared with high, educational attainment scored lower on cognitive measures [pooled unadjusted SMDs: 2-3 years = -0.32 (95% confidence intervals: -0.43 to -0.21); 4-7 years = -0.57 (-0.67; -0.47); 8-15 years = -0.54 (-0.72; -0.37)]. Analyses by GA subgroups (<27 vs ≥27 weeks) in children without severe neonatal morbidity and term controls yielded similar results.

CONCLUSIONS

Across diverse settings and regardless of the degree of prematurity, low maternal education was associated with lower cognition.

Hammersmith Infant Neurological Examination and long-term cognitive outcome in children born very preterm

AIM

To study the association between the Hammersmith Infant Neurological Examination (HINE) at age 2 years and neurocognition at age 11 years in children born very preterm. We hypothesized that the HINE at 2 years would be associated with neurocognition, that is, neurological, motor, and cognitive outcomes at 11 years.

METHOD

A total of 174 children (mean gestational age 29.0wks, SD 2.7; minimum 23.0, maximum 35.9; 95 [55%] males, 79 [45%] females) born very preterm (birthweight ≤1500g/gestational age <32wks), were included in a prospective cohort recruited from 2001 to 2006 in Turku, Finland. The HINE was performed at 2 years' corrected age. Neurocognition at 11 years was assessed with the Touwen neurological examination, Movement Assessment Battery for Children, Second Edition (MABC-2), and full-scale IQ (Wechsler Intelligence Scale for Children, Fourth Edition).

RESULTS

The HINE global score was associated with the results of the Touwen neurological examination (odds ratio [OR]=0.9, 95% confidence interval [CI] 0.8-0.9, p=0.001), MABC-2 (β=1.4, 95% CI 0.7-2.2, p<0.001), and full-scale IQ (β=1.2, 95% CI 0.8-1.7, p<0.001), even when adjusted. When children with cerebral palsy (CP) were excluded, the HINE was still associated with full-scale IQ (unadjusted β=1.2, 95% CI 0.3-2.1, p=0.01).

INTERPRETATION

A higher HINE global score at 2 years was associated with better general intelligence at 11 years even in children without CP. The HINE may be a useful tool to detect children at risk for later cognitive impairment. What this paper adds A Hammersmith Infant Neurological Examination (HINE) global score at 2 years was associated with long-term neurocognitive function. Severe cognitive impairment was significantly more common in 11-year-old children with complex minor neurological dysfunction compared to typically developing children. The HINE performed at 2 years detects risks of cognitive impairment at 11 years in children born very preterm. A higher HINE score at 2 years was associated with better general intelligence at 11 years.

Associations between Language at 2 Years and Literacy Skills at 7 Years in Preterm Children Born at Very Early Gestational Age and/or with Very Low Birth Weight

Preterm children (born <37 gestational weeks) who are born at very early gestational age (<32 weeks, very preterm, VP) and/or with very low birth weight (≤1500 g, VLBW) are at increased risk for language and literacy deficits. The continuum between very early language development and literacy skills among these children is not clear. Our objective was to investigate the associations between language development at 2 years (corrected age) and literacy skills at 7 years in VP/VLBW children. Participants were 136 VP/VLBW children and 137 term controls (a 6-year regional population cohort, children living in Finnish-speaking families). At 2 years of corrected age, language (lexical development, utterance length) was assessed using the Finnish version of the MacArthur-Bates Communicative Development Inventory and the Expressive Language Scale from Bayley scales of Infant Development, second edition. At 7 years, children's literacy skills (pre-reading skills, reading, and writing) were evaluated. Statistically significant correlations were found in both groups between language development at 2 years and literacy skills at 7 years (r-values varied between 0.29 and 0.43, p < 0.01). In the VP/VLBW group, 33% to 74% of the children with early weak language development had weak literacy skills at 7 years relative to those with more advanced early language skills (11% to 44%, p < 0.001 to 0.047). Language development at 2 years explained 14% to 28% of the variance in literacy skills 5 years later. Language development at 2 years had fair predictive value for literacy skills at 7 years in the VP/VLBW group (area under the receiver operating characteristic (ROC) curve (AUC) values varied between 0.70 and 0.77, p < 0.001). Findings provide support for the continuum between very early language development and later language ability, in the domain of literacy skills in preterm children.

The contributions of intelligence and executive function to behaviour problems in school-age children born very preterm

AIM

To examine the contributions of specific neurocognitive skills to behaviour problems in children born very preterm.

METHODS

We assessed children born <30 weeks' gestation or <1500 g at age 7 years using subtests of the Wechsler Intelligence Scale for Children Fourth Edition, performance and questionnaire-based measures of executive function, and Child Behavior Checklist and Teacher Rating Form. We evaluated the contributions of IQ and executive function to behaviour problems and the moderating effect of sex using multiple regression.

RESULTS

The 129 children (mean age = 7.2 years) had lower IQ, inferior executive function and increased internalising problems compared with normative samples. Verbal comprehension skills and working memory were associated with total, internalising and externalising problems at school. Performance-based and questionnaire-based executive function were associated with total and externalising behaviour problems both at home and school. Sex moderated the relationships between information processing and parent-reported total problems, and between teacher-rated executive function and total problems.

CONCLUSION

Both IQ and executive function are related to behaviour problems in children born very preterm, but the relationships are different in boys and girls. Executive function may be a useful target for intervention.

Single nucleotide vitamin D receptor polymorphisms (FokI, BsmI, ApaI, and TaqI) in the pathogenesis of prematurity complications

The vitamin D receptor (VDR), coded by the VDR gene, plays a pivotal role in executing cellular functions when bound by the active form of vitamin D. Gene polymorphisms in this receptor have been increasingly associated with a heightened state of vulnerability to certain diseases. However, limited data is available concerning the role of VDR gene polymorphisms in preterm infant complications. In 114 premature infants (< 32 weeks gestation) we analyze four single nucleotide VDR polymorphisms (rs2228570 (FokI), rs1544410 (BsmI), rs797532 (ApaI), rs731236 (TaqI)) for their association with respiratory distress syndrome (RDS), intraventricular hemorrhage (IVH), bronchopulmonary dysplasia (BPD), necrotizing enterocolitis (NEC) and retinopathy of prematurity (ROP). The results show that BPD was almost four times more likely in infants with the genotype CC of ApaI (rs7975232) (OR 3.845; p = 0.038). While both BPD and NEC were 2.1 times more likely to occur in preterm infants with the allele C of ApaI (rs7975232) (respectively: OR 2.111 and OR 2.129, p < 0.05). The ApaI VDR polymorphism appears to influence incidence of BPD and NEC in preterm infants. Considering VDR polymorphisms in future genetic investigations, in preterm complications, may prove clinically relevant.

Preterm children's developmental coordination disorder, cognition and quality of life: a prospective cohort study

OBJECTIVE

To evaluate the rate of developmental coordination disorder (DCD) and its correlation to cognition and self-experienced health-related quality of life (HRQoL) in children born very preterm.

DESIGN

Prospective follow-up study.

SETTING

Regional population of children born very preterm in Turku University Hospital, Finland, in 2001-2006.

PATIENTS

A total of 170 children born very preterm were followed up until 11 years of age.

MAIN OUTCOME MEASURES

Motor and cognitive outcomes were evaluated using the Movement Assessment Battery for Children - Second Edition (Movement ABC-2) and the Wechsler Intelligence Scale for Children - Fourth Edition, respectively, and HRQoL using the 17-Dimensional Illustrated Questionnaire (17D). The Touwen neurological examination was performed to exclude other neurological conditions affecting the motor outcome.

RESULTS

Eighteen children born very preterm (17 boys) (11.3%) had DCD, defined as Movement ABC-2 total test score ≤5th percentile. A positive correlation between motor and cognitive outcome (r=0.22, p=0.006) was found. Children born very preterm with DCD had lower cognitive scores than those without DCD (Full-Scale IQ mean 76.8 vs 91.6, p=0.001). Moreover, children born very preterm with DCD reported lower HRQoL than children born very preterm without motor impairment (17D mean 0.93 vs 0.96, p=0.03). However, HRQoL was higher in this group of children born very preterm compared with population-based normative test results (p<0.001).

CONCLUSIONS

DCD was still common at 11 years of age in children born very preterm in 2000s. DCD associated with adverse cognitive development and lower self-experienced HRQoL. However, this group of children born very preterm reported better HRQoL in comparison with Finnish norms.

A Follow-Up Study of Cognitive Development in Low Risk Preterm Children

The results of a longitudinal study on the cognitive development of one group of full-term and three groups of low risk preterm children with different gestational ages (GA) are presented. The 181 participants were divided into four GA groups of similar size. The aims were: 1) To check if there are differences in cognitive development (measured through the Batelle scale) among the GA groups. 2) To establish the predictive factors of cognitive development at 22 and 60 months of age, taking into account biomedical, environmental and individual factors. The results of the repeated measures ANOVA performed at 22 and 60 months of age indicated that the cognitive trajectories of the four GA groups were similar. Linear regression analyses showed that the effect of the different predictors changed in relation to the time of measurement of cognitive development. Biological factors and the quality of home environment had a moderate effect on the cognitive development at 22 months of age. Cognitive results obtained at 22 months of age, and, to a lesser extent, working memory had the greatest effect on cognitive development at 60 months. GA does not predict cognitive development. Preterm children do not show cognitive delay if they are healthy.

Neonatal Intestinal Failure Is Independently Associated With Impaired Cognitive Development Later in Childhood

OBJECTIVE

The impact of pediatric intestinal failure (IF) on neurodevelopment beyond infancy has not been systematically studied. Our aim was to evaluate cognitive and motor impairment and to identify risk factors for adverse outcomes among children with IF.

METHODS

We conducted a cross-sectional single-center study at the Helsinki University Children's Hospital. Patients with IF with >60 days of parental nutrition (PN) dependency aged between 3 and 16 years (n = 40) were invited to participate. The cognitive and motor skills were evaluated using validated tests: Wechsler Preschool and Primary Scale of Intelligence, 3rd edition, Wechsler Intelligence Scale for Children, 4th edition, and Movement Assessment Battery for Children, 2nd edition.

RESULTS

All the patients attending the study tests (n = 30, males = 24) were included. Their median age, gestational age, and birth weight was 7.5 (range 3-16) years, 35 (interquartile range [IQR] 28-38) weeks and 2238 (IQR 1040-3288) grams, respectively. Median duration of PN was 13 (IQR 5-37) months and 9 patients were currently on PN. Median intelligence quotient was 78 (IQR 65-91) and 10 (35%) patients had an intelligence quotient under 70 (-2 standard deviation). Significant motor impairment was detected in 10 patients (36%) and milder difficulties in 8 (28%). Adverse cognitive outcome was associated with neonatal short bowel syndrome, number of interventions under general anesthesia, and length of inpatient status, whereas adverse motor outcome was associated with prematurity.

CONCLUSION

Clinically significant cognitive and motor impairments are alarmingly common among neonatal patients with IF. We recommend early neurodevelopmental follow-up for all children with IF.

Executive Function Profiles at Home and at School in 11-Year-Old Very Low Birth Weight or Very Low Gestational Age Children

OBJECTIVE

Executive function (EF) problems of children born at very low birth weight (VLBW; ≤1500 g) or very low gestational age (VLGA; <32 gestational weeks) may present differently at school compared to the home environment. Ecological assessment of EF including parent- and teacher-rated profiles and associated risk factors of 11-year-old children born at VLBW or VLGA was evaluated.

METHODS

A total of 125 VLBW or VLGA children and 132 controls were assessed using the Behavior Rating Inventory of EF, which includes 8 subscales that form the Behavioral Regulation and Metacognition Indexes. For VLBW or VLGA children, full-scale intelligence quotient (IQ) was assessed using the Wechsler Intelligence scale for Children, Fourth Edition. Neonatal data were collected systematically.

RESULTS

VLBW or VLGA children with full-scale IQ ≥ 70 had clinically significant problems in the Working Memory subscale at school. Although they had clinically significant problems at home in the Behavioral Regulation Index, the difference disappeared when adjusted for paternal education. Lower gestational age, lower birth weight z-score, surgical necrotizing enterocolitis, low paternal and maternal education, and lower full-scale IQ were identified to be risk factors for higher scores in ecological assessment of EF.

CONCLUSION

VLBW or VLGA children in this cohort exhibit fewer EF problems in ecological assessment of EF compared to previous literature. EF problems of this study population vary by home and school setting and are emphasized in working memory at school. Screening for EF problems in school environment is recommended to target the support.

School performance is age appropriate with support services in very preterm children at 11 years of age

Aim

This Finnish regional birth‐cohort study compared the school performance of very preterm and full‐term children when they reached 11 years of age.

Methods

Teachers rated the educational abilities of 123 preterm children and 133 full‐term controls at the age of 11 years as well as the support services they received. The children were all born in the Turku University Hospital between 2001 and 2005. In the preterm group, neurosensory impairments were confirmed at two years of corrected age, and full‐scale intelligence quotient (IQ) was assessed at 11 years of age using the Wechsler Intelligence Scale, Fourth Edition.

Results

Educational abilities, including academic skills and classroom functioning, did not differ between the two groups after excluding the children with a full‐scale IQ < 70. However, 40% of the preterm group and 26% of the controls had received at least one support service (p <0.02). The 13 preterm children with a full‐scale IQ <70 and the 10 with neurosensory impairment received more support services. Boys in both groups displayed more classroom‐functioning problems than girls.

Conclusion

A full‐scale IQ ≥ 70 and age‐appropriate educational abilities do not exclude a significant need for support services in very preterm children at the age of 11 years.

Residential exposure to urban traffic is associated with the poorer neurobehavioral health of Ecuadorian schoolchildren

PURPOSE

We investigated whether chronic traffic-generated air pollution containing fine and ultrafine particulate matter is associated with reduced neurobehavioral performance and behavioral dysfunction in urban Ecuadorian schoolchildren. Also, we examined the effect of child hemoglobin and sociodemographic risk factors on these neurocognitive outcomes.

METHODS

A convenience sample of healthy children aged 8-14 years attending public schools were recruited in Quito, Ecuador. Child residential proximity to the nearest heavily trafficked road was used as a proxy for traffic-related pollutant exposure. These included high exposure (<100 m), medium exposure (100-199 m) and low exposure (≥ 200 m) from the nearest heavily trafficked road. The Behavioral Assessment and Research System (BARS), a computerized test battery assessing attention, memory, learning and motor function was used to evaluate child neurobehavioral performance. The Child Behavior Checklist (CBCL/6-18) was used to assess child behavioral dysfunction as reported by mothers. The data were analyzed using multiple linear regression.

RESULTS

Children with the highest residential exposure to traffic pollutants (< 100 m) had significantly longer latencies as measured by match to sample (b = 410.27; p = 0.01) and continuous performance (b = 37.90; p = 0.02) compared to those living ≥ 200 m away. A similar but non-significant association was observed for reaction time latency. Children living within 100 m of heavy traffic also demonstrated higher scores across all CBCL subscales although only the relationship with thought problems (p = 0.05) was statistically significant in the adjusted model.

CONCLUSION

The study findings suggest that children living within 100 m of heavy traffic appear to experience subtle neurobehavioral deficits that may result from fine and ultrafine particulate matter exposure.