Cognitive Development of Lead Exposed Children from Ages 6 to 15 Years: An Application of Growth Curve Analysis

The effect of lead exposure on cognitive growth patterns was assessed in a longitudinal study of 196 children. Performances on tests of verbal comprehension and perceptual organization (Vocabulary & Block Design, Wechsler Intelligence Scales for Children) were measured at ages 6.5, 11 and 15 years. Growth curve analyses revealed that the quadratic model best described the relationship between test scores and age. Children with higher lead levels, as measured at age 15 years, demonstrated lower verbal comprehension scores over time and greater decline in their rate of Vocabulary development at age 15 years, as compared to children with lower lead levels. Lead exposure was not significantly associated with growth in perceptual organization test scores. Socioeconomic status and maternal intelligence were statistically significantly associated with growth patterns for both test scores, independent of the effects of lead. The findings suggest that lead negatively impacts the developmental progression of specific cognitive skills from childhood through adolescence.     

An exploratory analysis of American Indian children's cultural engagement, fluid cognitive skills, and standardized verbal IQ scores

This exploratory cross-sectional study examined fluid cognitive skills and standardized verbal IQ scores in relation to cultural engagement amongst Tohono O'odham children (N = 99; ages 7 to 12 years). Guardians with higher socioeconomic status engaged their children in more cultural activities, and participation in more cultural activities contributed to higher standardized verbal IQ scores. Mean cognitive skill scores varied as a function of age and Tohono O'odham language knowledge. Children who understood and/or spoke Tohono O'odham started out with lower average scores than did children with no language knowledge, but mean scores generally increased in the older age groups such that they were equal to or higher than those of nonspeakers by age 9. Children with higher fluid cognitive skill scores had higher standardized verbal IQ scores than did children with lower scores.     

Profiles of children with specific reading comprehension difficulties

Background. Children with fluent and accurate word reading in the presence of poor text comprehension are impaired on a wide range of reading‐related tasks. Aims. This study investigated the consistency of skill impairment in a sample of poor comprehenders to identify any fundamental skill weakness that (i) might be associated with poor text comprehension, and (ii) might lead to depressed reading development. An additional aim was to determine whether reading comprehension difficulties are associated with more general educational difficulties. Sample. Twenty‐three poor comprehenders and 23 good comprehenders with age‐appropriate word reading accuracy were assessed when aged 8 years. Concurrent reading and language performance and reading, educational attainment and reasoning skills 3 years later are reported. Methods. The following skills were assessed when aged 8 years: word reading, text comprehension, vocabulary, syntax, cognitive ability, working memory, comprehension subskills. Listening comprehension, SAT scores and reasoning scores at 11 years are also reported. Results. There was no evidence for any fundamental skill weaknesses in the population of poor comprehenders at Time 1. However, poor vocabulary skills led to impaired growth in word reading ability and poor general cognitive ability led to impaired growth in comprehension. Poor comprehenders obtained lower SAT scores than did the good comprehenders at 11 years. Conclusions. These findings indicate that a single underlying source of poor comprehension is unlikely. Poor comprehenders are at risk of generally poor educational attainment, although weak verbal or cognitive skills appear to affect the reading development of poor comprehenders in different ways.     

Factor Analytic Studies Of Human Brain Damage: I. First And Second-Order Factors And Their Brain Correlates

This report is concerned with identifying the first and second-order cognitive factors underlying a battery of 49 measures taken from 22 brain damage tests. The test scores from 176 brain damaged patients between 16 and 65 years of age were intercorrelated and subjected to first-order alpha factoring followed by promax rotation to oblique simple structure. Ten of the 13 first-order factors extracted were interpretable, six of them being perceptual in nature and four being of a more conceptual nature. The perceptual factors include: perceptual organization, perceptual-motor speed, pattern recognition, temporal resolution, spatial orientation, and figure-ground identification. The conceptual factors include verbal comprehension, memory, and two abstraction factors. A second-order alpha factoring was performed on the matrix of correlations among the 13 primaries. Three of the five second-order factors extracted were interpretable. They were identified as perceptual integration (subsuming the first-order factors of perceptual organization, perceptual-motor speed, and temporal resolution), verbal memory (subsuming verbal comprehension and memory), and visualization (subsuming spatial orientation and figure-ground identification). Although factor interpretations were based primarily on the patterns of high loading variables, they were also influenced by lesion effects observed in this and related studies. About half the interpretable factors are relatively localized (i.e., confined to one or two lobes of one hemisphere), with the other half more diffuse (i.e., multi-lobed, combined with laterality or bilaterality). The more localized factors include the right hemisphere factors of perceptual-motor speed, temporal resolution, and spatial orientation, and the left hemisphere factors of verbal comprehension, memory, and verbal memory. The more neurally diffuse factors include the second-order factors and such broad gauged first-order factors as abstraction I and II, and pattern recognition. Furthermore, same lobe, bilaterally hemispheric effects were rare, and only four factors (memory, verbal memory, visualization, and abstraction I) were correlated with sub-cortical lesions.     

Assessment of Working Memory Capacity in Preschool Children Using the Missing Scan Task

The purpose of this study was to investigate the feasibility and validity of a modified version of Buschke's missing scan methodology, the Missing Scan Task (MST), to assess working memory capacity (WMC) and cognitive control processes in preschool children 3–6 years in age. Forty typically developing monolingual English‐speaking children between 36 and 84 months in age participated in the study. The children were tested on measures of WMC (MST), verbal and nonverbal memory (NEPSY Narrative Memory and Memory for Designs subtests), and language skills (Peabody Picture Vocabulary Test, fourth edition). Children showed increased working memory capacity scores with age, as measured by the MST, with significant differences between 3‐ and 5‐year‐olds and 3‐ and 6‐year‐olds. Significant correlations were also found between the MST and language and verbal and nonverbal memory scores. MST scores still remained significantly correlated with the other measures of memory even after age and global language were accounted for in a regression analysis, demonstrating that the MST captures unique variance related specifically to WMC and cognitive control processes used to retrieve and scan information in short‐term memory (STM). The results of this study demonstrate that the MST is a feasible and valid methodology for assessing WMC in preschool children as young 3 years of age. Copyright © 2014 John Wiley & Sons, Ltd.     

Children's cognitive ability from 4 to 9 years old as a function of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence

This study examined the effects of prenatal cocaine exposure, environmental risk, and maternal verbal intelligence on children's cognitive ability. Gender and age were examined as moderators of potential cocaine exposure effects. The Stanford-Binet IV intelligence test was administered to 231 children (91 cocaine exposed, 140 unexposed) at ages 4, 6, and 9 years. Neonatal medical risk and other prenatal exposures (alcohol, cigarettes, and marijuana) were also examined for their unique effects on child IQ. Mixed models analysis indicated that prenatal cocaine exposure interacted with gender, as cocaine-exposed boys had lower composite IQ scores. Age at assessment did not moderate this relation, indicating that cocaine-exposed boys had lower IQs across this age period. A stimulating home environment and high maternal verbal IQ also predicted higher composite IQ scores. Cocaine-exposed boys had lower scores on the Abstract/Visual Reasoning subscale, with trends for lower scores on the Short-Term Memory and Verbal Reasoning subscales, as exposure effects were observed across domains. The findings indicate that cocaine exposure continues to place children at risk for mild cognitive deficits into preadolescence. Possible mechanisms for the Exposure x Gender interaction are discussed.     

New and updated tests of print exposure and reading abilities in college students

The relationship between print exposure and measures of reading skill was examined in college students (N = 99, 58 female; mean age = 20.3 years). Print exposure was measured with several new self-reports of reading and writing habits, as well as updated versions of the Author Recognition Test and the Magazine Recognition Test (Stanovich & West, 1989). Participants completed a sentence comprehension task with syntactically complex sentences, and reading times and comprehension accuracy were measured. An additional measure of reading skill was provided by participants' scores on the verbal portions of the ACT, a standardized achievement test. Higher levels of print exposure were associated with higher sentence processing abilities and superior verbal ACT performance. The relative merits of different print exposure assessments are discussed.     

The effect of age-at-testing on verbal memory among children following severe traumatic brain injury

Memory deficits are a common sequelae following childhood traumatic brain injury (TBI), which often have serious implications on age-related academic skills. The current study examined verbal memory performance using the Rey Auditory Verbal Learning Test (RAVLT) in a pediatric TBI sample. Verbal memory abilities as well as the effect of age at-testing on performance were examined. A sample of 67 children following severe TBI (age average = 12.3 ± 2.74) and 67 matched controls were evaluated using the RAVLT. Age effect at assessment was examined using two age groups: above and below 12 years of age during evaluation. Differences between groups were examined via the 9 RAVLT learning trials and the 7 composite scores conducted out of them. Children following TBI recalled significantly less words than controls on all RAVLT trials and had significantly lower scores on all composite scores. However, all of these scores fell within the low average range. Further analysis revealed significantly lower than average performance among the older children (above 12 years), while scores of the younger children following TBI fell within average limits. To conclude, verbal memory deficits among children following severe TBI demonstrate an age-at-testing effect with more prominent problems occurring above 12 years at the time of evaluation. Yet, age-appropriate performance among children below 12 years of age may not accurately describe memory abilities at younger ages following TBI. It is therefore recommended that clinicians address child’s age at testing and avoid using a single test as an indicator of verbal memory functioning post TBI.     

Using developmental principles to assist preschoolers in developing numeracy and literacy

In a yoked control design, 4-yr.-olds (N = 39) in a Head Start program played numerous structured games involving either the oddity principle or letter identification and letter sounds. The children's mean age was 53.2 mo.; SD = 4.1 mo. Three were Middle Eastern, 14 were Latino, 7 were East African, and 15 were African American. Children showed better mastery of oddity after playing games directed at this concept, and numeracy scores on the Woodcock-Johnson III were better for children who had played this type of game. Woodcock-Johnson III Letter-Word scores for children who had played the oddity and seriation or letter games were equivalent. These results are consistent with other research indicating that the understanding of oddity relations may be a key transitional thinking which supports quantitative and verbal development at the preschool-kindergarten interface. The standardized test scores indicate that guided play directed at this aspect of cognitive growth or more narrowly directed at early literacy can produce equivalent knowledge of letters.     

Neighborhood Social Context and Individual Polycyclic Aromatic Hydrocarbon Exposures Associated with Child Cognitive Test Scores

Childhood cognitive and test-taking abilities have long-term implications for educational achievement and health, and may be influenced by household environmental exposures and neighborhood contexts. This study evaluates whether age 5 scores on the Wechsler Preschool and Primary Scale of Intelligence-Revised (WPPSI-R, administered in English) are associated with polycyclic aromatic hydrocarbon (PAH) exposure and neighborhood context variables including poverty, low educational attainment, low English language proficiency, and inadequate plumbing. The Columbia Center for Children’s Environmental Health enrolled African-American and Dominican-American New York City women during pregnancy, and conducted follow-up for subsequent childhood health outcomes including cognitive test scores. Individual outcomes were linked to data characterizing 1-km network buffers around prenatal addresses, home observations, interviews, and prenatal PAH exposure data from personal air monitors. Prenatal PAH exposure above the median predicted 3.5 point lower total WPPSI-R scores and 3.9 point lower verbal scores; the association was similar in magnitude across models with adjustments for neighborhood characteristics. Neighborhood-level low English proficiency was independently associated with 2.3 point lower mean total WPPSI-R score, 1.2 point lower verbal score, and 2.7 point lower performance score per standard deviation. Low neighborhood-level educational attainment was also associated with 2.0 point lower performance scores. In models examining effect modification, neighborhood associations were similar or diminished among the high PAH exposure group, as compared with the low PAH exposure group. Early life exposure to personal PAH exposure or selected neighborhood-level social contexts may predict lower cognitive test scores. However, these results may reflect limited geographic exposure variation and limited generalizability.     

Postnatal exposure to methyl mercury and neuropsychological development in 7-year-old urban inner-city children exposed to lead in the United States

Background: The most common route for general population exposure to methyl mercury (MeHg) is fish consumption. Recommendations to pregnant women about consuming fish contaminated with MeHg are also applied to children, but there are few studies available about the effects of low-level postnatal MeHg exposure in them.

Objectives: To investigate the association between postnatal methyl mercury exposure and neuropsychological development in a study of children also exposed to lead, both measured at 7 years.

Methods: We measured MeHg concentrations in blood samples from the Treatment of Lead-Exposed Children (TLC) trial in which 780 children with elevated concentrations of lead in blood were followed with neuropsychological tests from ages 12–33 months through 7 years. Here we examine blood MeHg concentration and neuropsychological test scores, both measured at age 7 years. We used a maximum likelihood method to estimate geometric mean MeHg concentration and generalized linear regression models to analyze MeHg and neuropsychological test scores.

Results: Geometric mean MeHg concentration was 0.56 (95% confidence interval: 0.52, 0.59) μg/L. A 1 μg/L increase in MeHg was associated with a 2.1 (95% confidence interval: 0.4, 3.8) point increase in Full-Scale IQ and 0.2 (95% confidence interval: 0.02, 0.4) point increase in Learning Slopeindex T-score on a test of verbal memory.

Conclusions: Our results suggest that the relatively low MeHg exposure in US school-aged children from this population has no detectable adverse effect on neuropsychological development. The positive associations observed between MeHg and neurodevelopment may indirectly reflect consumption of beneficial polyunsaturated fatty acids from seafood.     

学前儿童抑制控制的发展趋势及其对言语理解和数学认知的预测作用

以长春市某幼儿园的122名3~6岁幼儿为被试,采用2(测试任务:无嵌套规则白天黑夜任务,有嵌套规则的白天黑夜任务)×2(测试时间:间隔9个月的第一次测试和第二次测试)×4(年龄分组:3.00~3.75岁组,3.76~4.50岁组,4.51~5.25岁组,5.26~6.00岁组)的三因素混合设计,来分析不同复杂程度的抑制控制在学前阶段的发展趋势,并在控制幼儿年龄和工作记忆水平后,分析不同复杂程度抑制控制对言语理解和数学认知的独立预测作用。结果发现:(1)对3~6岁儿童来说,有嵌套规则的白天黑夜任务的难度水平要显著高于无嵌套规则的白天黑夜任务;(2)较简单的抑制控制(无嵌套规则的白天黑夜任务)在学前阶段的发展速度先快后慢,但较复杂的抑制控制(有嵌套规则的白天黑夜任务)在3~6岁期间持续快速发展;(3)独立于年龄和工作记忆,较复杂的抑制控制能够显著预测幼儿的数学认知和言语理解,但较简单的抑制控制对言语理解和数学认知的预测作用不显著。根据上述结果,在描述学前儿童抑制控制发展趋势时要注意任务难度的设定,而且难度适当的抑制控制任务成绩更能预测幼儿的言语理解和数学认知。     

The association of oral hydroxyurea therapy with improved cognitive functioning in sickle cell disease.

This study examined potential cognitive benefits of oral hydroxyurea therapy for children with sickle cell disease (SCD). Cognitive abilities of 15 children with SCD on hydroxyurea were compared to 50 other children with SCD, controlling for demographics and hematocrit. Children on hydroxyurea scored significantly higher on tests of verbal comprehension, fluid reasoning, and general cognitive ability than children not on the drug. The data therefore provide preliminary evidence of cognitive benefits of hydroxyurea. Mechanisms for this effect may be improved blood/oxygen supply to the brain or reduced fatigue and illness.     

Just a talking book? Word learning from watching baby videos

This study examined the relationship between viewing an infant DVD and expressive and receptive language outcomes. Children between 12 and 15 months were randomly assigned to view Baby Wordsworth, a DVD highlighting words around the house marketed for children beginning at 12 months of age. Viewings took place in home settings over 6 weeks. After every 2 weeks and five exposures to the DVD, children were assessed on expressive and receptive communication measures. Results indicated there was no increased growth on either outcome for children who had viewed the DVD as compared to children in the control group, even after multiple exposures. After controlling for age, gender, cognitive developmental level, income, and parent education, the most significant predictor of vocabulary comprehension and production scores was the amount of time children were read to.     

Individual and developmental differences in eyewitness recall and suggestibility in children with intellectual disabilities

This study examined two key issues: (1) whether there were developmental improvements in eyewitness memory performance for children with intellectual disabilities (ID); and (2) whether standardised measures of cognitive ability and suggestibility would relate to eyewitness recall and suggestibility. Children with ID and age‐matched controls (ages 8/9 and 12 years) watched a video of a crime and were asked a range of open‐ended and specific questions about the event in a subsequent interview. Free recall increased between the two age levels for children with and without ID, but at a faster rate for those without ID. For other question types, differences in performance between children with and without ID were far more marked than age differences. Standardised measures of interrogative suggestibility (Gudjonsson Suggestibility Scale, GSS), verbal IQ, non‐verbal IQ, mental age and speed of information processing were related to eyewitness performance. In particular, higher eyewitness recall scores (free recall, non‐leading specific questions) were related to higher scores on the standardised GSS free recall measure; and higher eyewitness suggestibility scores were related to higher scores on the standardised GSS suggestibility measures. Mental age was a better predictor of performance on a range of eyewitness memory question types than verbal or non‐verbal IQ; and speed of information processing showed some relationships with eyewitness performance. Copyright © 2006 John Wiley & Sons, Ltd.     

A parent-offspring adoption study of cognitive abilities in early childhood

Do cognitive abilities in early childhood relate genetically and/or environmentally to isomorphic abilities in adulthood? Are specific cognitive abilities diffentiated in early childhood in terms of their prediction of adult cognitive abilities? The present study, the first behavioral genetic analysis of specific cognitive abilities in early childhood, explored these questions using parent-offspring data for 186 adopted children and 151 nonadopted children tested in the longitudinal Colorado Adoption Project at 3 years of age and 162 adopted children and 138 nonadopted children tested at 4 years. The children's Stanford-Binet IQ and scores for four specific cognitive abilities (verbal, spatial, perceptual speed, and memory) were correlated with corresponding measures for their parents—the biological and adoptive parents of the adopted children and the natural parents of the nonadopted children. Significant correlations were found between biological mothers' IQ and the IQ of their adopted away offspring at 3 and 4 years of age, suggesting genetic influence for IQ. However, specific cognitive abilities yielded no significant correlations between biological mothers and their adopted-away offspring. These results suggest that substantial genetic continuity exists for IQ from early childhood to adulthood, but not for specific cognitive abilities.     

The Role of Paternal Age in the Prediction of Offspring Intelligence

Recent evidence suggests that paternal age at birth influences myriad developmental outcomes among children, but few studies have examined the possibility for father's age to influence children's intellectual development among a sample of high-risk families. The authors use data from the Fragile Families and Child Wellbeing Study to examine the association between paternal age at birth among 480 male and 449 female children's verbal IQ scores, as assessed with a version of the Peabody Picture Vocabulary Test at 9 years old. The nonlinear association between paternal age and children's verbal intelligence was also examined. Paternal age at birth appears to have a marginally significant nonlinear relationship with male children's verbal IQ scores, despite controlling for a number of possible confounders associated with both young and advanced paternal age.     

Social perception and WAIS-IV Performance in adolescents and adults diagnosed with Asperger's Syndrome and Autism

Previous research using the Wechsler scales has identified areas of cognitive weaknesses in children, adolescents, and adults diagnosed with Autism or Asperger's syndrome. The current study evaluates cognitive functioning in adolescents and adults diagnosed with Autism or Asperger's syndrome using the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) and the Social Perception subtest from the Advanced Clinical Solutions. Deficits in social perception, verbal comprehension, and processing speed were found in the Autism sample. Additionally, they exhibited inconsistent performance on auditory working memory and perceptual reasoning tasks. The Asperger's syndrome group had better overall cognitive skills than the Autism group, but compared with controls, they had weaknesses in processing speed, social perception, and components of auditory working memory. Both groups had relatively low scores on the WAIS-IV Comprehension subtest compared with the other verbal comprehension subtests. Clinical application and utility of the WAIS-IV and Social Perception in Autism Spectrum Disorders are discussed.     

Motor and cognitive proficiency of learning disabled and normal children

Motor and cognitive skills of learning disabled (N = 32) and normal (N = 32) boys were compared on the Modified Lincoln-Oseretsky Motor Development Scale and on the WISC-R Vocabulary and Block Design subtests. Eight learning disabled and eight normal boys were tested at four age levels from 8 to 11 years. All boys were of normal intelligence. Motor and cognitive skills of the learning disabled boys were significantly below those of the normal boys and below those of the normative group. Chronological age was not a significant factor in relationship to either motor or cognitive skills. Intercorrelations indicated that in the learning disabled group Block Design, but not Vocabulary, was significantly related to motor scores at the 8- and 9-year ages. These results suggest that a common factor relating to perceptual-motor coordination and efficiency may be involved on the Lincoln-Oseretsky and Block Design subtest for young learning disabled children but not for older learning disabled children or for normal children.