Development of language, memory, and visuospatial abilities in 5‐ to 12‐year‐old children using a neuropsychological battery

Norms, convergent validity, test-retest reliability, and practice effects for verbal fluency overall performance, clustering, and switching in Spanish-speaking children

OBJECTIVE

We conducted two empirical studies (in a cross-sectional and a longitudinal design) with the aim at establishing normative data (including norms for strategy use [i.e., clustering and switching strategies] and performance over time), and examining the convergent validity, the test-retest reliability (3-4 wks interval) and the changes in performance with practice (1 year interval) of the different verbal fluency (VF) quantitative and qualitative scores in Spanish-speaking children and adolescents.

METHOD

In S1 (n = 620 6- to 15-year-old Spanish-speaking children and adolescents), MANCOVA and Pearson's correlations were employed. In S2 (n = 148 6- to 12-year-old Spanish-speaking children), intraclass correlation coefficient (ICC), paired t-tests, and Confirmatory Factor Analysis (CFA) were used.

RESULTS

S1 results showed an age effect on all VF measures (quantitative and qualitative). The number of switches/clusters was more related to total word productivity and to executive functions (EF) than the mean cluster size. In S2, a significant increase in phonological VF performance was observed on number of switches and word productivity scores from baseline (Time 1) to repeat testing at Time 2. Practice effects were observed at Time 3 on all measures except for semantic and phonological mean cluster size. Test-retest reliability coefficients at Time 2 for number of clusters and switches, but not for mean cluster size, fell in the moderate range, ranging from ICCs .61 to ICCs .81. Test-retest reliability coefficients for total word productivity were higher (ICCs above .80) and stronger when testing as a unity with CFA methods (ϕ=.94, p < .001).

CONCLUSIONS

These data may be relevant for informing the neuropsychological assessment of spontaneous cognitive flexibility in children with typical development (TD) and those with developmental or acquired disorders.

Neurodevelopmental assessments used to measure preschoolers' cognitive development in Latin America: a systematic review

OBJECTIVE

The objective of this study was to systematically review the standardized neurodevelopmental assessments used to study preschool-aged children's cognitive development in Spanish-speaking Latin America.

METHODS

The authors systematically searched PubMed, PsycINFO, and ERIC databases for peer-reviewed articles from Spanish-speaking Latin American countries. Articles were included if they measured cognitive development among children aged 2-6 years using at least one standardized assessment tool; 97 articles were included and reviewed in accordance with PRISMA guidelines to assess their use of these tools.

RESULTS

Ninety-seven studies across 13 countries used a total of 41 assessments to measure cognitive development; most widely used were the Wechsler intelligence scales (n = 46/97), particularly the Wechsler Preschool and Primary Scale of Intelligence and Wechsler Intelligence Scale for Children (n = 23 and 29, respectively). Other common assessments included the McCarthy Scales of Children's Abilities (n = 9), Raven's Progressive Matrices (n = 9), Child Neuropsychological Assessment (n = 8), and Peabody Picture Vocabulary Test (n = 7). In regions where normative data for a given assessment were unpublished, authors commonly used norms from the United States, Mexico, or Spain or did not report standard scores in their analyses.

CONCLUSIONS

The wide range of tools used in these studies presents a challenge for generalizing results when measuring the neurodevelopment of Latin American preschool-aged children. The low availability of normative data for specific regions reveals concerns if some tools are culturally and linguistically appropriate even when Spanish is a common language, particularly in low-resource settings. Future work to forge greater consistency in the use of validated measures, clarity in reporting research methods, and publication of regional normative data would benefit the field.

The Childhood Executive Functioning Inventory (CHEXI) Parent and Teacher Form: Factor Structure and Cognitive Correlates in Spanish-speaking Children from Argentina

The aims of the present study were: (1) to explore the CHEXI factor structure parent (n = 183) and teacher (n = 206) forms in Spanish-speaking children aged 6 to 11  years, (2) to analyze the relationship between parent- and teacher-rated data and performance-based measures of EF (including working memory, inhibition, and cognitive flexibility tasks) and academic achievement and (3) to examine the association between parents and teachers reports. Confirmatory Factor analysis (CFA) showed that the two-factor model including (1) Working memory and (2) Inhibition best fit the data. McDonald's Omega coefficient was adequate for both the total parents (ω = .98). and teachers' (ω = .98) scales. In addition, low and selective associations were found between performance and rater-based assessments. However, stronger associations were observed between CHEXI and academic performance with differences according to the informant (parents vs. teachers). Finally, low correlations were found between parents and teachers reports. Taken together, our results suggest that the CHEXI is a reliable measure to assess EF in Argentinean Spanish-speaking children, supporting existing evidence that proposes that ratings and performance-based measures would assess different underlying mental constructs. Clinical and educational implications for considering both perspectives during neuropsychological assessment, further including parent- and teacher-rated reports are discussed.

Demographically-adjusted norms for selected tests of verbal fluency: Results from the Neuropsychological Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) project

OBJECTIVE

Verbal fluency tests are sensitive to various disorders affecting the central nervous system and are commonly included in neuropsychological evaluations. We aimed to develop normative data for two verbal fluency tests in a sample of native Spanish-speakers living in the US-Mexico border region.

METHOD

Participants included 254 adults from the Neuropsychological Norms for the US-Mexico Border Region in Spanish (NP-NUMBRS) Project (Age: range = 19-60; Education: range = 0-20, 59% female). Participants completed two verbal fluency tests (i.e., letter [PMR] and semantic/category fluency [Animal Naming]) as part of a larger neuropsychological test battery. We examined linear and nonlinear effects of demographic factors (age, education, and gender) on verbal fluency raw scores, and developed T-scores using fractional polynomial equations controlling for demographics. We also calculated the rates of "impairment" (T-scores < 40) that would be obtained by applying the newly developed norms and available norms for non-Hispanic English-speakers on comparable tests.

RESULTS

There were positive small effects of age and medium effects of education on verbal fluency raw scores. The normalized distribution of T-scores with the new norms showed expected psychometric properties. However, rates of impairment for both letter and semantic fluency were significantly higher when applying non-Hispanic White norms, and significantly lower when applying non-Hispanic Black norms.

CONCLUSIONS

We provide norms for Spanish-speakers living along the US-Mexico border region for two verbal fluency tests that are co-normed with a more extensive neuropsychological battery. These regional norms will improve interpretation of verbal fluency test performance in Spanish-speakers living in the US-Mexico borderland.

Confirmatory Factor Analysis of the BRIEF-2 Parent and Teacher Form: Relationship to Performance-Based Measures of Executive Functions and Academic Achievement

We conducted two empirical studies to (1) explore the dimensionality of the Behavior Rating Inventory of Executive Function-2 (BRIEF-2) parent and teacher forms, (2) examine the association between the parent and teacher reports, and (3) analyze the relationship between the BRIEF-2 ratings and performance-based measures of executive functions (EFs) (including working memory, inhibition, and shifting tasks) and academic achievement in children. In Study 1 (n = 212 parents; n = 111 teachers), confirmatory factor analysis (CFA) showed that a three-factor solution that included the indices of (1) behavior regulation, (2) emotion regulation, and (3) cognitive regulation best fit the data. In Study 2 (n = 275 8- to 12-year-old Spanish-speaking children), selective and low correlations were found between performance- and rater-based measures of EFs. In addition, low to moderate correlations were found between parent and teacher reports. However, the three indices of both forms of the BRIEF-2 were associated with the diverse academic domains analyzed, although differences emerged depending on the informant (teacher vs. parent). Our results support the hypothesis that the two EF measures document different underlying processes. The clinical and educational implications of considering both perspectives in the assessment of EFs in children with typical development and in children with neurodevelopmental disorders are discussed.

Identifying neuropsychological predictors of drawing skills in elementary school children

Much evidence indicates that drawing is related to different neuropsychological abilities in children. However, a comprehensive cognitive model of drawing in children is still lacking. Here, we conducted a study on the neuropsychological predictors of drawing in a sample of 142 typically developing elementary school children (M age = 8.8 years; SD = 1.1). Based on a path analysis, we examined the contribution of visual perception (matching geometrical figures), complex spatial abilities (e.g., complex figures identification and mental rotation), visual attention, working memory, verbal and visual-motor skills, as well as of gender, age and socio-economic status, to copying the Rey-Osterrieth Complex Figure (ROCF). Results showed that ROCF copying was influenced in a specific and additive way by visual perception, visual-motor coordination, and verbal abilities as well as age, while it was indirectly related to visual attention, working memory, and to complex spatial abilities. These findings provide the grounds for identifying the neuropsychological bases of drawing in elementary school children.

Normative data of the Rey-Osterrieth Complex Figure for Italian-speaking elementary school children

The Rey-Osterrieth Complex Figure Test (ROCF) is a widely used neuropsychological test for the evaluation of drawing disorders in different clinical populations, and, in particular, in persons with neurodevelopmental disorders. The aim of the present study is to provide normative data for ROCF copying (ROCF-Direct copy) and drawing from memory (ROCF-Immediate recall) in Italian-speaking children. The sample consisted of 348 children (147 males and 199 females), aged 7-11 years, recruited from elementary schools in Southern Italy. Normative data were gathered from 312 participants fulfilling the inclusion criteria, and estimated centiles were obtained according to the LMS method providing normalized growth centile standards. Results showed a significant effect of age on performance in both tasks, with a steady increase of drawing accuracy, whereas participants' gender and mean level of parental education did not exert any significant effect. Thus, normative data were stratified by age, and percentile scores were provided allowing a practical use of the ROCF for the clinical evaluation of drawing abilities in both typical and atypical children.

Computerized versus manual versions of the Wisconsin Card Sorting Test: Implications with typically developing and ADHD children

The aims of Study 1 (S1) were (a) to compare the task performance of 361 typically developing (TD) children aged 7 to 12 years, according to the mode of Wisconsin Card Sorting Test (WCST) administration (manual vs. computerized) and b) to examine the contributions of executive functions (EFs) (i.e., working memory [WM], shifting and inhibition) to each WCST version. The objectives of Study 2 (S2) were (a) to study the comparability of the results obtained from the manual version to the results from the computer version in 43 children with Attention Deficit/Hyperactivity Disorder (ADHD) and (b) to compare task performance on both versions between children with ADHD and TD children. The effect of age was only significant for the manual WCST. Regression analyses revealed that WM and shifting contributed to manual WCST performance, whereas WM and inhibition contributed to the performance on the computer version. We observed differences depending on the WCST mode of administration, as better scores for the manual version were recorded for both TD children and children with ADHD, despite similar performance on tasks involving other EFs. Additionally, children with ADHD performed worse than TD children on both versions. Our findings suggest that verbal face-to-face interactions would play a significant role in supporting children's abilities to solve novel situations characterized by uncertainty.

The effects of implicit encouragement and the putative confession on children's memory reports

The current study tested the effects of two interview techniques on children's report productivity and accuracy following exposure to suggestion: implicit encouragement (backchanneling, use of children's names) and the putative confession (telling children that a suspect "told me everything that happened and wants you to tell the truth"). One hundred and forty-three, 3-8-year-old children participated in a classroom event. One week later, they took part in a highly suggestive conversation about the event and then a mock forensic interview in which the two techniques were experimentally manipulated. Greater use of implicit encouragement led to increases, with age, in children's narrative productivity. Neither technique improved or reduced children's accuracy. No increases in errors about previously suggested information were evident when children received either technique. Implications for the use of these techniques in child forensic interviews are discussed.

Rey-Osterrieth Complex Figure - copy and immediate recall (3 minutes): Normative data for Spanish-speaking pediatric populations

OBJECTIVE

To generate normative data for the Rey-Osterrieth Complex Figure (ROCF) in Spanish-speaking pediatric populations.

METHOD

The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the ROCF as part of a larger neuropsychological battery. The ROCF copy and immediate recall (3 minutes) scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses.

RESULTS

The final multiple linear regression models showed main effect for age on copy and immediate recall scores, such that scores increased linearly as a function of age. Age2 affected ROCF copy score for all countries, except Puerto Rico; and ROCF immediate recall scores for all countries, except Chile, Guatemala, Honduras, Paraguay, and Puerto Rico. Models indicated that children whose parent(s) had a MLPE >12 years obtained higher scores compared to children whose parent(s) had a MLPE≤12 years for Chile, Puerto Rico, and Spain in the ROCF copy, and Paraguay and Spain for the ROCF immediate recall. Sex affected ROCF copy and immediate recall score for Chile and Puerto Rico with girls scoring higher than boys.

CONCLUSIONS

This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate approach to interpret the ROCF Test in pediatric populations.

Shortened Version of the Token Test: Normative data for Spanish-speaking pediatric population

OBJECTIVE

To generate normative data for the Shortened Version of the Token Test in Spanish-speaking pediatric populations.

METHOD

The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the Shortened Version of the Token Test as part of a larger neuropsychological battery. Shortened Version of the Token Test total scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses.

RESULTS

The final multiple linear regression models showed main effects for age in all countries, such that score increased linearly as a function of age. In addition, age2 had a significant effect in all countries, except Guatemala and Puerto Rico. Models showed that children whose parent(s) had a MLPE >12 years obtained higher score compared to children whose parents had a MLPE ≤12 years in Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, Puerto Rico, and Spain. The child's sex did not have an effect in the Shortened Version of the Token Test total score for any of the countries.

CONCLUSIONS

This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate interpretation of the Shortened Version of the Token Test when used in pediatric populations.

Earlier Alcohol Use Onset Predicts Poorer Neuropsychological Functioning in Young Adults

BACKGROUND

Neurodevelopment may be shaped by environmental factors such as alcohol intake. Over 20% of U.S. high school students begin drinking before age 14, and those who initiated drinking before age 14 are 4 times more likely to develop psychosocial, psychiatric, and substance use difficulties than those who began drinking after turning 20. Little is known, however, about how the age of alcohol use onset influences brain development.

METHODS

This study prospectively examined the effects of alcohol use onset age on neurocognitive functioning in healthy adolescent drinkers (N = 215). Youth were administered a neuropsychological battery before substance use initiation (M = 13.6 years, SD = 0.8) and on average 6.8 years later (M = 20.2 years, SD = 1.5). Hierarchical linear regressions examined if earlier ages of onset for first and regular (i.e., weekly) alcohol use adversely influenced neurocognition, above and beyond baseline neurocognition, substance use severity, and familial and social environment factors.

RESULTS

As hypothesized, an earlier age of first drinking onset (AFDO) predicted poorer performance in the domains of psychomotor speed and visual attention (ps<0.05, N = 215) and an earlier age of weekly drinking onset (AWDO) predicted poorer performances on tests of cognitive inhibition and working memory, controlling for baseline neuropsychological performance, drinking duration, and past-year marijuana use (ps<0.05, N = 127). No relationship between AFDO and AWDO was found with verbal learning and memory and visuospatial ability.

CONCLUSIONS

This is the first study to assess the association between age of adolescent drinking onset and neurocognitive performance using a comprehensive test battery. This study suggests that early onset of drinking increases risk for alcohol-related neurocognitive vulnerabilities and that initiation of any or weekly alcohol use at younger ages appears to be a risk factor for poorer subsequent neuropsychological functioning. Findings have important implications for public policies related to the legal drinking age and prevention programming. Further studies are needed to replicate these preliminary findings and better understand mediating processes and moderating conditions.

Measurement of expressive vocabulary in school-age children: Development and application of the Kilifi Naming Test (KNT)

The dearth of locally developed measures of language makes it difficult to detect language and communication problems among school-age children in sub-Saharan African settings. We sought to describe variability in vocabulary acquisition as an important element of global cognitive functioning. Our primary aims were to establish the psychometric properties of an expressive vocabulary measure, examine sources of variability, and investigate the measure's associations with non-verbal reasoning and educational achievement. The study included 308 boys and girls living in a predominantly rural district in Kenya. The developed measure, the Kilifi Naming Test (KNT), had excellent reliability and acceptable convergent validity. However, concurrent validity was not adequately demonstrated. In the final regression model, significant effects of schooling and area of residence were recorded. Contextual factors should be taken into account in the interpretation of test scores. There is need for future studies to explore the concurrent validity of the KNT further.

Neurocognitive Functions in 3- to 15-Year-Old Children: An International Comparison

OBJECTIVES

Performance on neurocognitive tasks develops with age, but it is still unknown whether this performance differs between children from different cultures. We compared cross-sectionally the development of neurocognitive functions in 3- to 15-year-old children from three countries: Finland, Italy, and the United States (N=2745).

METHODS

Language, face memory, emotion recognition, theory of mind, and visuospatial processing subtests from the NEPSY-II standardizations in Finland, Italy, and the United States were used to evaluate if children and adolescents from different linguistic and cultural backgrounds differ in performance on these measures.

RESULTS

We found significant differences in performance on the tasks between the countries. Generally, the differences were more pronounced in the younger age groups. Some subtests showed greater country effects than others, performance on these subtests being higher, in general, in one country over the others, or showed different patterns of age associated changes in test performance.

CONCLUSIONS

Significant differences in neurocognitive performance between children from Finland, Italy, and the United States were found. These findings may be due to cultural or educational differences that impact test performance, or due to factors associated with the adaptation of measures from one culture to another. The finding of performance differences across countries on similar tasks indicate that cross-cultural and background variables impact performance on neuropsychological measures. Therefore, clinicians need to consider a child's cultural background when evaluating performance on neuropsychological assessments. The results also indicate that future cross-cultural studies are needed to further examine the underlying cultural factors that influence neurocognitive performance. (JINS, 2017, 23, 367-380).

Sex and Handedness in Development of Visuomotor Skills

Development of visuomotor skills in 420 left-handed and 420 right-handed school children were investigated using the Rey-Osterrieth Complex Figure. Analysis indicate that the visuomotor skills involved in copying a complex figure improve with age until the mean age of 10.5 yr., in both sex and handedness groups. Further analysis showed that girls performed significantly better than boys at certain developmental stages and right-handers performed better than left-handers in various age groups. Some possible differences in performance could be attributed to different rates of maturation of the cerebral hemispheres, to different neuropsychological strategies, or to functional differences between the sex groups and between right- and left-handed children.

Cognitive Development of Fluent and Nonfluent Bilingual Speakers Assessed with Tachistoscopic Techniques

A tachistoscopic study investigated verbal skills among bilingual speakers, 10 fluent and 15 nonfluent, on rhyming and semantic tasks in both their native (Greek) and second (English) languages. Fluent bilinguals scored higher on all tasks, especially on the English rhyming and the Greek semantic tasks. They also responded faster, especially on the English semantic task. Fluent bilingual speakers scored higher on the Uses of Objects Test, an index of creativity. Nonfluent bilinguals had higher grades in geometry and arithmetic at school while fluent bilinguals had higher grades in Greek composition.

Beyond the bilingual advantage: The potential role of genes and environment on the development of cognitive control

In recent years there has been considerable debate about the presence or absence of a bilingual advantage in tasks that involve cognitive control. Our previous work has established evidence of differences in brain activity between monolinguals and bilinguals in both word learning and in the avoidance of interference during a picture selection task. Recent models of cognitive control have highlighted the importance of a set of neural structures that may show differential tuning due to exposure to two languages. There is also evidence that genetic factors play a role in the availability of dopamine in neural structures involved in cognitive control. Thus, it is important to investigate whether there are interactions effects generating variability in language acquisition when attributed to genetic (e.g., characteristics of dopamine turnover) and environmental (e.g., exposure to two languages) factors. Here preliminary results from genotyping of a sample of bilingual and monolingual individuals are reported. They reveal different distributions in allele frequencies of the DRD2/ANKK1 taq1A polymorphism. These results bring up the possibility that bilinguals may exhibit additional flexibility due to differences in genetic characteristics relative to monolinguals. Future studies should consider genotype as a possible contributing factor to the development of cognitive control across individuals with different language learning histories.

Structure and Invariance of Executive Functioning Tasks across Socioeconomic Status: Evidence from Spanish-Speaking Children

The aim of the present study was to analyze the latent structure of executive functions (EFs) in Spanish-speaking children and to test measurement invariance across socioeconomic status (SES). We sampled 248 children, aged 8 to 12, who were divided into two groups: 124 children from a medium socioeconomic status (MSS) and 124 children from a low socioeconomic status (LSS). We applied a neuropsychological battery consisting of various EF tasks and performed confirmatory factor analysis (CFA) and multi-group CFA (MGCFA). CFA showed best fit for the three factor solution: (a) Working memory, (b) Cognitive flexibility, and (c) Inhibition. Moreover, the MGCFA revealed that the three-factor solution was invariant (configural, metric, and structural) across SES, allowing valid comparison between the groups (MSS and LSS) of factors. Finally, bifactorial MANOVA revealed a significant effect of SES and group age but not for the interaction between the two in the three EF dimensions indicative of quantitative group differences. Results are discussed in terms of the dimensional nature of the EF construct and the effects of SES on executive functioning.

The rise and fall of immediate and delayed memory for verbal and visuospatial information from late childhood to late adulthood

Over 100,000 verbal and visuospatial immediate and delayed memory tests were presented via the Internet to over 28,000 participants in the age range of 11 to 80. Structural equation modeling pointed to the verbal versus visuospatial dimension as an important factor in individual differences, but not the immediate versus delayed dimension. We found a linear decrease of 1% to 3% per year in overall memory performance past the age of 25. For visuospatial tests, this decrease started at age 18 and was twice as fast as the decrease of verbal memory. There were strong effects of education, with the highest educated group sometimes scoring one full standard deviation above the lowest educated group. Gender effects were small but as expected: women outperformed men on the verbal memory tasks; men outperformed women on the visuospatial tasks. We also found evidence of increasing proneness to false memory with age. Memory for recent news events did not show a decrease with age.

Psychometric data for the revised token test in normally developing Mexican children ages 4-12 years

Language comprehension is vital to social and educational development but few pediatric tests are available for its assessment. To approach this problem, two versions of the Token Test (TT), "TT short form" (DeRenzi & Faglioni, 1978) and "Revised Token Test" (RTT), were first compared. Using a sample of 88 normally developing Spanish-speaking children, the tests were compared on their: (a) established psychometric development and (b) internal consistency. The RTT was judged to be superior and was selected for additional experimentation. The RTT was compared with a developmental measure of lexical knowledge on a cross-sectional sample of 250 4-12-year-old normally developing Spanish-speaking children. A significant positive and high correlation supports its concurrent validity. Significant differences across the age groups, along with a principal component analysis that yielded a three-factor structure, support its construct validity. Preliminary normative data across the nine age groups are provided.

Working memory limitations in children with severe language impairment

In the present study, the relations of various aspects of working memory to various aspects of language problems in a clinical sample of 97 Dutch speaking 5-year-old children with severe language problems were studied. The working memory and language abilities of the children were examined using an extensive battery of tests. Working memory was operationalized according to the model of Baddeley. Confirmative factor analyses revealed three memory factors: phonological, visual and central executive. Language was construed as a multifactorial construct, and confirmative factor analyses revealed four factors: lexical-semantic abilities, phonological abilities, syntactic abilities and speech production abilities. Moderate to high correlations were found between the memory and language factors. Structural equation modelling was used to further explore the relations between the different factors. Phonological memory was found to predict phonological abilities; central-executive memory predicted lexical-semantic abilities; and visual memory predicted speech production abilities. Phonological abilities also predicted syntactic abilities. Both the theoretical and clinical implications of the findings are discussed.

LEARNING OUTCOMES

The reader will be introduced to the concepts of multifactorial components of working memory as well as language impairment. Secondly the reader will recognize that working memory and language impairment factors can be related. Particular emphasis will be placed on phonological memory, central-executive memory and visual memory and their possible prediction of specific components of language impairment.

Verbal (animal) fluency scores in age/grade appropriate minority children from low socioeconomic backgrounds

Two hundred-thirteen children in grades 1 through 8 were asked to rapidly generate as many names of animals as they could in 60 seconds. These children were age appropriate for their grade level in school, did not receive any form of special education services, and as a group showed (estimated) average intellectual ability. They were primarily from minority (particularly Hispanic) backgrounds and came from families with low socioeconomic status. Normative data are presented. Hierarchical multiple regression analysis revealed that the age range/grade level score accounted for 21.5% of the variability in fluency scores and the Vocabulary level of the child accounted for an additional 5.7%. Level of performance on this animal fluency task was not lower than what has been reported in primarily white children from middle socioeconomic backgrounds.

What can be localized in the brain? Toward a "factor" theory on brain organization of cognition

A theoretical integration attempt among the lesional (neuropsychological), physiological (functional), and psychometric models of cognition is presented in this article. Recent neuroimaging techniques particularly fMRI have shown that there are some brain functions (i.e., simple) that can be localized into single brain areas whereas there are others (i.e., complex) that cannot. Clinical neuropsychology has been able to propose some "cognitive factors" based on empirical observations in patients with brain lesions. Factor analysis in psychometry may provide an additional tool to extract some constitutive elements of psychological functions (factors). "Factors" in factor analysis, however, may have different levels of specificity. Some times they refer to functional systems (complex cognition); in other occasions to elements of cognition ("cognitive factors"). It is emphasized that the very same brain areas (and cognitive factors) may be potentially involved in different types of cognition. It is proposed that complex cognition depends on specific patterns of activation of different brain areas and specific circuitries ("modules"), each one making its own contribution to the whole system (functional system). Impairment in a specific cognitive factor, on the other hand, may result in diverse types of impairments. At the moment, it seems feasible to suppose some cognitive factors responsible for normal neuropsychological performance. Theoretically, the impairment in any of these factors could be responsible for some specific neuropsychological syndromes.

Validity of the Rey Visual Design Learning Test in Primary and Secondary School Children

The Rey Visual Design Learning Test (Rey, 1964, cited in Spreen & Strauss, 1991, Wilhelm, 2004) assesses immediate memory span, new learning, delayed recall and recognition for nonverbal material. Two studies are presented that focused on the construct validity of the RVDLT in primary and secondary school children. In the first study, primary school children performed the RVDLT and the Biber Figural Learning Test, as well as the WISC-R Block design Test, Boston Naming Test, and the Trailmaking Test, to assess discriminant validity. In the second study, the age range was expanded and the subtest Visual Reproductions of the Wechsler Memory Scale with a Delayed recall phase was used to assess the construct validity. A test for visual-motor integration and a test for attention, concentration, and speed of information processing were also added to complete the test battery for assessing discriminant validity. Moderate to high correlations were found between scores on the RVDLT and the tests used to assess construct validity. The correlational pattern of RVDLT scores and the scores on the discriminant tests is discussed.

Cultural values underlying psychometric cognitive testing

It is proposed that culture (values, beliefs, styles of behavior) can affect neuropsychological testing. Cognitive testing represents a social situation that-as any social situation, it is one governed by implicit cultural rules. At least eight different culture-dependent values underlie cognitive testing: (1) One-to-one relationship, (2) Background authority, (3) Best performance, (4)Isolated environment (5) Special type of communication, (6) Speed, (7) Internal or subjective issues, and (8) The use of specific testing elements and strategies. In addition, it is proposed that"the distance" (e.g., gender, age, ethnicity) between the examiner and the examinee may potentially impact the testing situation. A special analysis regarding the function of instruction in cognitive tests is also presented emphasizing that test instruction interpretation is also culture-dependent. Some potential avenues of research are finally proposed.

The influence of the parents' educational level on the development of executive functions

Information about the influence of educational variables on the development of executive functions is limited. The aim of this study was to analyze the relation of the parents' educational level and the type of school the child attended (private or public school) to children's executive functioning test performance. Six hundred twenty-two participants, ages 5 to 14 years (276 boys, 346 girls) were selected from Colombia and Mexico and grouped according to three variables: age (5-6, 7-8, 9-10, 11-12, and 13-14 years), gender (boys and girls), and school type (private and public). Eight executive functioning tests taken from the Evaluacion Neuropsicologica Infantil; Matute, Rosselli, Ardila, & Ostrosky, (in press) were individually administered: Semantic Verbal Fluency, Phonemic Verbal Fluency, Semantic Graphic Fluency, Nonsemantic Graphic Fluency, Matrices, Similarities, Card Sorting, and the Mexican Pyramid. There was a significant effect of age on all the test scores and a significant effect of type of school attended on all but Semantic Verbal Fluency and Nonsemantic Graphic Fluency tests. Most children's test scores, particularly verbal test scores, significantly correlated with parents' educational level. Our results suggest that the differences in test scores between the public and private school children depended on some conditions existing outside the school, such as the parents' level of education. Implications of these findings for the understanding of the influence of environmental factors on the development of executive functions are presented.

Studying Toxicants as Single Chemicals: Does this Strategy Adequately Identify Neurotoxic Risk?

Despite the fact that virtually all chemicals exposure of humans are to mixtures, and that these mixed exposures occur in the context of numerous other risk modifiers, our current understanding of human health risks is based almost entirely on the evaluation of chemicals studied in isolation. This paper describes findings from our collaborative studies that prompt questions about these approaches in the context of neurotoxicology. The first section describes studies investigating the interactions of maternal Pb exposure with maternal stress. Examined across a range of outcome measures, it shows that maternal Pb can modulate the effects of maternal stress, and, conversely, stress modifies the effects of Pb. Further, effects of Pb+stress could be detected in the absence of an effect of either risk factor alone, and, moreover, the profile of effects of Pb alone differs notably from that of Pb+stress. Collectively, interactions were not systematic, but differed by brain region, gender and outcome measure. A second section describes outcomes of studies examining combined exposures to the pesticides paraquat (PQ) and maneb (MB) during development which likewise reveal potentiated effects of combined exposures. They also demonstrate examples of both progressive and cumulative neurotoxicity, including a marked vulnerability following gestational exposure to MB, to the effects of PQ, a pesticide with no structural relationship to MB. The ability of current hazard identification and risk assessment approaches to adequately identify and encompass such effects remains an important unanswered question. One consideration proposed for further evaluating potential interactions that may be of significance for the nervous system is based on a multi-hit hypothesis. It hypothesizes that the brain may readily compensate for the effects of an individual chemical itself acting on a particular target system, but when multiple target or functional sites within that one system are attacked by different mechanisms (i.e., multiple chemical exposures or chemical exposures combined with other risk factors), homeostatic capabilities may be restricted, thereby leading to sustained or cumulative damage.

Normative data for the Boston Naming Test in native Dutch-speaking Belgian children and the relation with intelligence

This paper reports the results of a normative study of the 60-item version of the Boston Naming Test (BNT) in a group of 371 native Dutch-speaking Flemish children between the ages of 6 and 12 years. Analysis of test results revealed that BNT performance was significantly affected by age and gender. The gathered norms were shown to be significantly lower than published norms for comparable North-American children. Error analysis disclosed remarkable similarities with data from elderly subjects, with verbal semantic paraphasias and 'don't know' responses occurring most frequently. Finally, BNT scores were shown to correlate strongly with general intelligence as measured with the Raven Progressive Matrices. The relation between both measures can be of help in the diagnosis of identification naming deficits and impaired word-retrieval capacities.

The impact of culture and education on non-verbal neuropsychological measurements: a critical review

Clinical neuropsychology has frequently considered visuospatial and non-verbal tests to be culturally and educationally fair or at least fairer than verbal tests. This paper reviews the cross-cultural differences in performance on visuoperceptual and visuoconstructional ability tasks and analyzes the impact of education and culture on non-verbal neuropsychological measurements. This paper compares: (1) non-verbal test performance among groups with different educational levels, and the same cultural background (inter-education intra-culture comparison); (2) the test performance among groups with the same educational level and different cultural backgrounds (intra-education inter-culture comparisons). Several studies have demonstrated a strong association between educational level and performance on common non-verbal neuropsychological tests. When neuropsychological test performance in different cultural groups is compared, significant differences are evident. Performance on non-verbal tests such as copying figures, drawing maps or listening to tones can be significantly influenced by the individual's culture. Arguments against the use of some current neuropsychological non-verbal instruments, procedures, and norms in the assessment of diverse educational and cultural groups are discussed and possible solutions to this problem are presented.

Neuropsychological test scores, academic performance, and developmental disorders in Spanish-speaking children

Limited information is currently available about performance of Spanish-speaking children on different neuropsychological tests. This study was designed to (a) analyze the effects of age and sex on different neuropsychological test scores of a randomly selected sample of Spanish-speaking children, (b) analyze the value of neuropsychological test scores for predicting school performance, and (c) describe the neuropsychological profile of Spanish-speaking children with learning disabilities (LD). Two hundred ninety (141 boys, 149 girls) 6- to 11-year-old children were selected from a school in Bogotá, Colombia. Three age groups were distinguished: 6- to 7-, 8- to 9-, and 10- to 11-year-olds. Performance was measured utilizing the following neuropsychological tests: Seashore Rhythm Test, Finger Tapping Test (FTT), Grooved Pegboard Test, Children's Category Test (CCT), California Verbal Learning Test-Children's Version (CVLT-C), Benton Visual Retention Test (BVRT), and Bateria Woodcock Psicoeducativa en Español (Woodcock, 1982). Normative scores were calculated. Age effect was significant for most of the test scores. A significant sex effect was observed for 3 test scores. Intercorrelations were performed between neuropsychological test scores and academic areas (science, mathematics, Spanish, social studies, and music). In a post hoc analysis, children presenting very low scores on the reading, writing, and arithmetic achievement scales of the Woodcock battery were identified in the sample, and their neuropsychological test scores were compared with a matched normal group. Finally, a comparison was made between Colombian and American norms.

Effects of age on neurocognitive measures of children ages 5 to 12: a cross-sectional study on 800 children from the United States

The standardization of the NEPSY-A Developmental Neuropsychological Assessment (Korkman, Kirk, & Kemp, 1998) provided an opportunity to study the effects of age across the age range 5 to 12 years. Test scores of 800 children on 20 subtests of NEPSY were analyzed. These measures are based on traditions of neuropsychological assessment and are thought to reflect attention and executive functions, language, sensorimotor functions, visuospatial functions, and memory and learning. The effects of age were very significant on all measures, confirming the developmental sensitivity of the NEPSY. The effects of age were more significant in the 5- to 8-year age range than in the 9- to 12-year range. Only performance on tasks of fluency and memory span for sentences showed significant age effects in the 10- to 12-year age range. This suggests that neurocognitive development is rapid in the 5- to 8-year age range and more moderate in the 9- to 12-year age range.

The Rey figure in Amazonia: effects of jungle living on childrens' copy performance

This exploratory case study investigated the organizational strategies and visual-motor integration skills of 6 children living in the Amazon rainforest of Peru. As expected, a developmental trend was observed for age as older children generally required less time to draw a complex design and produced better renditions than younger children. Unexpectedly, all children, including those below the age of 8, utilized the left side of the design as an anchor in adopting a left to right strategic approach to task solution. Results are discussed in terms of potential sociocultural and neurobiological influences on brain organization, development of cognitive abilities, and potential for cultural bias when evaluating ethnic minority children.

A reconceptualization of learning disabilities via a self-organizing systems paradigm

A dilemma exists regarding the interpretation of learning disabilities. A self-organizing systems (SOS) paradigm suggests widespread, diffuse outcomes, whereas a specific learning disability concept suggests more localized dysfunction. There may be very good reason to doubt the veridicality of the concept of a specific learning disability, not because the construct of learning disabilities itself is a frivolous concept, as some have held, but because the biological or neurological events that underlie a learning disability do not remain focal and constrained only to specific dysfunction. It is important to know whether an identified learning disability remains contained or whether processing disorders might be found in other areas. The assessment profiles of school-age children identified with nonverbal learning disabilities (NLD), assumed to have primarily right-hemispheric brain dysfunctions, and children with language-based learning disabilities (LLD), assumed to have primarily left-hemispheric brain dysfunctions, were examined to explore learning disabilities using an SOS paradigm. The pilot study reported here is used as an exemplar of how a self-organizing systems paradigm is conceptualized. Although a more comprehensive study is needed to confirm the data, this exemplar suggests that overflow into areas not typically associated with each disability subtype may occur. Concerns regarding ways of determining discrepancy for diagnostic purposes are noted, and remediation strategies designed for specific disabilities are questioned.

Neuropsychological and behavioral assessment of ADHD in seven- to twelve-year-old children: a discriminant analysis

We hypothesized that children with attention-deficit/hyperactivity disorder (ADHD) would underperform on neuropsychological tests that are sensitive to executive function impairments. We further proposed that a linear discriminant analysis using behavioral and neuropsychological variables as dependent variables would pinpoint the capability of behavioral questionnaires and neuropsychological tests to predict the correct classification of ADHD and control children. We designed a transversal study with 62 seven- to twelve-year-old children with ADHD and 62 Full Scale IQ-matched controls using two behavioral scales and 13 neuropsychological tests. Using analysis of variance and covariance with age and school achievement and multifactor analysis of variance, we found that behavioral variables established robust, statistically significant differences between groups (p < .001). Children with ADHD scored worse than controls on 31 out of 61 neuropsychological variables. Children with ADHD, however, obtained better scores that were statistically significant on WISC-R Comprehension and Picture completion. A linear discriminant analysis with nine behavioral variables correctly classified 100% of the participants in both groups. Another linear discriminant analysis using 10 neuropsychological variables correctly classified 85.48% of the participants in both groups. We propose a core battery of selected tests for assessing children with ADHD. The significance of cross-cultural analyses of different developmental disturbances is emphasized.

Executive dysfunctions in children with attention deficit hyperactivity disorder

One hundred and twenty-four male children ranging in age from seven to 12 years-old were selected. The sample was divided into two groups: (1) sixty-two with attention deficit hyperactivity disorder (ADHD) children; and (2) sixty-two normal matched controls (N-ADHD). Three tests were individually administered: (1) Wisconsin Card Sorting Test (WCST); (2) Verbal fluency and semantics (animals and fruits); and, (3) Picture Arrangement subtest of the WISC-R. For all the test scores, statistically significant differences were found between both ADHD and N-ADHD groups. Two separate factor analyses were performed, using the normal and ADHD groups. Four factors were found for the N-ADHD group, which accounted for 85.7% of the variance. The factor structure presented some similarities in both groups: Factor 2, 3 and 4 in the control group corresponded to factors 1, 2 and 3 in the ADHD group. Nonetheless, in the ADHD group Factor 1 (Abstraction and Flexibility Factor) was absent. Results are interpreted as supporting the hypothesis of executive dysfunction in children with ADHD.

A Note of Caution: Normative Neuropsychological Test Performance: Effects of Age, Education, Gender and Ethnicity: A Comment on Saykin et al. (1995)

Recently Saykin et at. (1995), departing from their results in a sample of normal individuals, concluded that, "Demographic factors infrequently account for more than 10% of the variance for many neuropsychological teat scores" (p. 79). In this short article it is pointed out that their results have to be interpreted with extreme caution, because the education and age ranges they used are not valid to analyze the education and age effects on neuropsychological test performance. Educational effect does not represent a linear effect; rather, it represents a kind of negatively accelerated curve, and age effect becomes evident only in a population older than the sample they have selected.

Specific learning disabilities: a neuropsychological perspective

A dispersion in cognitive abilities is expected in normal populations. Specific learning disabilities would represent an extreme polarity in a continuum of normal cognitive dispersion. Three propositions relative to learning disabilities are advanced in the present paper. First, specific learning disabilities are expected to be found for diverse cognitive functions, even though some of these specific learning disorders have yet to be described in scientific literature. Second, it is noted that specific "factors" can be affected in cases of learning disabilities. Lastly, a parallel between focal neuropsychological syndromes and specific learning disabilities is proposed. Developmental learning difficulties would represent dysfunctional or dysmaturational defects; whereas neuropsychological syndromes represent a consequence of acquired structural brain pathology.

Cognitive effects of cocaine and polydrug abuse

One hundred and eighty-three participants were divided into three groups containing: 61 cocaine-dependent; 59 polydrug-dependent; and 63 normal subjects. All were evaluated using a basic neuropsychological assessment battery. The dependent groups exhibited significantly lower scores on short-term memory, attention, and concept formation tests. Performance on some subtests correlated negatively with the length of dependency and frequency of substance use. As compared with the control group, the dependent groups exhibited significant differences in the following personal and family areas: (a) depression and anxiety traits; (b) self-aggression and lack of fear in childhood; (c) family history of substance dependency; and (d) difficulties with interpersonal relationships. The operation of predisposing developmental factors for substance dependence is suggested.