Children's sleep and cognitive performance: a cross-domain analysis of change over time

Relations between changes in children's cognitive performance and changes in sleep problems were examined over a 3-year period, and family socioeconomic status, child race/ethnicity, and gender were assessed as moderators of these associations. Participants were 250 second- and third-grade (8-9 years old at Time 1) boys and girls. At each assessment, children's cognitive performance (Verbal Comprehension, Decision Speed) was measured using the Woodcock-Johnson III Tests of Cognitive Abilities, and sleep problems (Sleepiness, Sleep/Wake Problems) were collected via self-report. Individual growth models revealed that children who reported increases in Sleepiness exhibited little growth in Verbal Comprehension over time compared with their peers who reported decreases in Sleepiness, resulting in a nearly 11-point cognitive deficit by the end of the study. These associations were not found for Sleep/Wake Problems or Decision Speed. Child race/ethnicity and gender moderated these associations, with Sleepiness serving as a vulnerability factor for poor cognitive outcomes, especially among African American children and girls. Differences in cognitive performance for children with high and low Sleepiness trajectories ranged from 16 to 19 points for African American children and from 11 to 19 points for girls. Results build substantially on existing literature examining associations between sleep and cognitive functioning in children and are the first to demonstrate that children's sleep trajectories over 3 waves were associated with changes in their cognitive performance over time.     

Correlations for Wechsler Intelligence Scale for Children--Revised and the Wechsler Preschool and Primary Scale of Intelligence for Iranian children.

This study focused on the relationship between the Wechsler Intelligence Scale for Children--Revised (WISC--R) and the Wechsler Preschool and Primary Scale of Intelligence (WPPSI) given to 40 6-yr.-old Iranian children. Pearson correlations between the WISC--R and the WPPSI IQs and between scaled scores on the corresponding subtests were significant. The comparison of mean IQs and scaled scores indicates that the WISC--R yielded a significantly higher Verbal IQ and higher scores on Information, Vocabulary, Comprehension, and Picture Completion than the WPPSI. The mean difference between corresponding Verbal and Full Scale IQs was not significant. These results suggest that scores on the two instruments correlated well for these 6-yr.-old Iranian children and the content on which IQs for the recently restandardized WISC--R and WPPSI are based are related.     

Construct validity of Wechsler factor scores.

The construct validity of the Verbal Comprehension. Perceptual Organization, and Freedom from Distractibility factor scores was examined in a sample of school-aged referred children. Examination of correlations between factor scores and neuropsychological and achievement tests generally supported the construct validity of the factors. The Verbal Comprehension factor was associated with verbal, quantitative, and concept-formation abilities. The Perceptual Organization factor was related to nonverbal concept formation, tactual performance, and visual attention. The Freedom from Distractibility factor demonstrated a complex pattern of correlations and appeared to reflect a range of abilities including quantitative, language, attentional, and concept formation.     

Indice d’aptitude général pour le WISC-IV : normes francophones

The Wechsler Children Intelligence Scale–Fourth Edition (WISC-IV, 2005) allows to calculate the FSIQ and four index scores: verbal comprehension, perceptual reasoning, working memory, and processing speed. In 1998, Prifitera and colleagues recommended to calculate the General Ability Index (GAI), as an alternative composite score. This score is based on Verbal Comprehension and Perceptual Reasoning only. The objective of the first study presented in this paper is to provide the GAI normative tables for the French WISC-IV; these tables were created using a statistical approximation procedure. The objective of the second study is to test the validity of these tables with data obtained from 60 children. Correlation between FSIQ and GAI is 0.91 and the relative mean difference is only 0.18 point. These tables, for the French version of the WISC-IV, allow using the GAI as an alternative measure of general ability.     

Verbal ability and executive functioning development in preschoolers at head start

Research suggests that executive functioning skills may enhance the school readiness of children from disadvantaged homes. Questions remain, however, concerning both the structure and the stability of executive functioning among preschoolers. In addition, there is a lack of research addressing potential predictors of longitudinal change in executive functioning during early childhood. This study examined the structure of executive functioning from fall to spring of the preschool year using a multimethod battery of measures. Confirmatory factor analyses revealed a unidimensional model fit the data well at both time points, and tests of measurement invariance across time points indicated that children's mean latent executive functioning scores significantly improved over time. Verbal ability was a significant predictor of longitudinal change in executive functioning. Theoretical implications and directions for future research are discussed.     

Confirmatory factor analysis of the WAIS-IV/WMS-IV

The Wechsler Adult Intelligence Scale-fourth edition (WAIS-IV) and the Wechsler Memory Scale-fourth edition (WMS-IV) were co-developed to be used individually or as a combined battery of tests. The independent factor structure of each of the tests has been identified; however, the combined factor structure has yet to be determined. Confirmatory factor analysis was applied to the WAIS-IV/WMS-IV Adult battery (i.e., age 16-69 years) co-norming sample (n = 900) to test 13 measurement models. The results indicated that two models fit the data equally well. One model is a seven-factor solution without a hierarchical general ability factor: Verbal Comprehension, Perceptual Reasoning, Processing Speed, Auditory Working Memory, Visual Working Memory, Auditory Memory, and Visual Memory. The second model is a five-factor model composed of Verbal Comprehension, Perceptual Reasoning, Processing Speed, Working Memory, and Memory with a hierarchical general ability factor. Interpretative implications for each model are discussed.     

WISC-R subtest but no overall VIQ-PIQ difference in Dutch children with PDD-NOS

VIQ-PIQ differences have been studied in children with autism and Asperger syndrome but have not been studied in a separate group of children with PDD-NO, although, PDD-NOS has a much higher prevalence rate than autism and deficits in communication and social interaction are severe. The Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered to 100 children, aged 6-12 years, with PDD-NOS (n = 76), autism (n = 13), and Asperger syndrome (n = 11). PDD-NOS was diagnosed using explicit research criteria. No overall differences between VIQ and PIQ were found in PDD-NOS and autism. Peaks in the subtest scores on Information, Similarities, Picture Arrangement, and Mazes, and troughs in the subtest scores on Comprehension, Digit Span, and Coding were demonstrated in children with PDD-NOS. Their score on the Freedom from Distractibility factor was lower than the scores on the Verbal Comprehension factor and the Perceptual Organization factor. Children with PDD-NOS seemed to have a similar VIQ-PIQ profile as children with autism, and on the subtest level children with PDD-NOS showed some similarities to children with Asperger syndrome or autism. It was not possible to distinguish PDD-NOS from autism or Asperger syndrome by using IQ scores.     

WISC-R Subtest But No Overall VIQ–PIQ Difference in Dutch Children with PDD-NOS

VIQ–PIQ differences have been studied in children with autism and Asperger syndrome but have not been studied in a separate group of children with PDD-NO, although, PDD-NOS has a much higher prevalence rate than autism and deficits in communication and social interaction are severe. The Wechsler Intelligence Scale for Children-Revised (WISC-R) was administered to 100 children, aged 6–12 years, with PDD-NOS (n = 76), autism (n = 13), and Asperger syndrome (n = 11). PDD-NOS was diagnosed using explicit research criteria. No overall differences between VIQ and PIQ were found in PDD-NOS and autism. Peaks in the subtest scores on Information, Similarities, Picture Arrangement, and Mazes, and troughs in the subtest scores on Comprehension, Digit Span, and Coding were demonstrated in children with PDD-NOS. Their score on the Freedom from Distractibility factor was lower than the scores on the Verbal Comprehension factor and the Perceptual Organization factor. Children with PDD-NOS seemed to have a similar VIQ–PIQ profile as children with autism, and on the subtest level children with PDD-NOS showed some similarities to children with Asperger syndrome or autism. It was not possible to distinguish PDD-NOS from autism or Asperger syndrome by using IQ scores.     

Longitudinal models of developmental dynamics between reading and cognition from childhood to adolescence

The authors applied linear dynamic models to longitudinal data to examine the dynamics of reading and cognition from 1st to 12th grade. They used longitudinal data (N=445) from the Connecticut Longitudinal Study (S. E. Shaywitz, B. A. Shaywitz, J. M. Fletcher, & M. D. Escobar, 1990) to map the dynamic interrelations of various scales of the Wechsler Intelligence Scales for Children--Revised (i.e., Full, Performance, and Verbal) and specific markers of the Woodcock-Johnson Psycho-Educational Battery--Revised reading cluster (i.e., Letter-Word ID, Decoding, and Comprehension). The results of these analyses indicate that (a) there is a positive dynamic relation between reading and cognition across the selected age range; (b) this dynamic relation is symbiotic, with positive influences in both directions; (c) the influence from cognition to reading is stronger when considering the Wechsler Intelligence Scales for Children Performance--Revised Performance scale and weaker with the Verbal scale; (d) when examining the different Reading subtests, the influences from cognition are more apparent for Letter-Word ID and Comprehension and are less perceptible for Decoding; and (e) the dynamics of reading and cognition appear to be of stronger magnitude during 1st to 3rd grade, less strong during 4th to 8th grade, and weaker from 9th to 12th grade.     

Conceptual tempo as a moderator variable in predicting first grade achievement test scores

This study examined the utility of a set of tests for predicting the academic achievement of separate samples of impulsive and reflective first graders. The predictor tests were the Peabody Picture Vocabulary Test, the Columbia Mental Maturity Scale, Wepman's Auditory Discrimination Test, the ITPA Sound Blending Subtest, the WISC Digit Span Subtest, and Kaufman's WISC-R Verbal Comprehension Factor (Comprehension, Information, Similarities, and Vocabulary). The criterion measures were drawn from the Stanford Achievement Test and included scores for Total Auditory, Total Mathematics, Total Reading, Vocabulary and Listening Comprehension. Multiple regression analyses revealed that (a) for three of the five criterion variables, the optimal equations for predicting the achievement test scores differed for impulsives and reflectives, and (b) given the same predictor scores, the predicted achievement of impulsive and reflective children different considerably. It was concluded that conceptual tempo is an important moderator variable in predicting academic performance.     

Validities of Unit-Weighted Composites of the ASVAB and the ECAT Battery

Currently, assignment to training in each entry-level enlisted job in the U.S. military is influenced by examinees’ scores on the classification composite for that job from the Armed Services Vocational Aptitude Battery (ASVAB). For a cross-service sample of the 18 occupations in the Enhanced Computer-Administered Test (ECAT) project, enhancements of their respective operational ASVAB composites (9 unique ones) are evaluated here. Analyses are reported on the gains in validity from adding 1 test with unit weight to each composite, the addition coming either from the other ASVAB tests or from the 9 tests of the ECAT battery. In more than half the schools, the best ASVAB additions were Coding Speed or Mechanical Comprehension. In the ECAT battery, 1 test of psychomotor ability (Two-Hand Tracking) and 2 tests of working memory (Mental Counters and Sequential Memory) were the most promising additions. The utility of the new composites for person–job matching is discussed.     

Factor analysis of the Wechsler adult intelligence scale-revised (WAIS-R): An examination of the standardization sample

Orthogonal and oblique factor analyses were performed using the Wechsler Adult Intelligence Scale-Revised (WAIS-R) standardization sample (Wechsler, 1981). Using objective criteria, it was decided to retain two factors. Evidence for a strong general intelligence (g) factor was found from both the orthogonal and oblique rotations. Whereas the verbal IQ provided an acceptable estimate of the Verbal Comprehension factor, a purer measure was found in the form of a Verbal Comprehension Deviation Quotient containing only the Information, Vocabulary, Comprehension, and Similarities subtests. The performance IQ was found to be an inadequate measure of the Perceptual Organization factor. A Perceptual Organization Deviation Quotient, containing only the Block Design and Object Assembly subtests, was recommended as an effective alternative. Analysis of the variance components for each subtest at every age level revealed that a substantial proportion of subtests at a wide range of age levels evidence either high or intermediate levels of specific variance. These results are discussed in terms of interpreting individual subtest scores and patterns. Each of the study's major findings are compared with prior work done with the Wechsler Adult Intelligence Scale (WAIS) (Wechsler, 1955).     

Validity of a short form of the WISC-III in children with traumatic head injury

The concurrent, construct, and criterion validities of Donders' (in press) short form of the Wechsler Intelligence Scale for Children - Third Edition (WISC-III) were evaluated in a sample of 171 children with traumatic head injury (THI). Correlations between the short-form deviation quotients and their full-length counterparts were statistically significant. Confirmatory factor analysis revealed that a four-factor model (composed of Verbal Comprehension, Perceptual Organization, Freedom from Distractibility, and Processing Speed) fit the data relatively well. The short-form deviation quotients also had statistically significant correlations with length of coma. It is concluded that this short form is an accurate and valid alternative to the full-length WISC-III in children with THI.     

Smoking among Norwegian schoolchildren 1975–1980: II. The influence of the social environment

In 1975 all primary schools in Norway were asked to carry out local studies of the smoking habits of all pupils in grades 6–9 (age 12–15). A sample of 6968 questionnaires from the pupils (those born on the sixth irrespective of month) forms the empirical basis of the present study. Among ninth graders (age 15) coming from homes where both parents smoked and the children were permitted to smoke, 67% of the boys and 78% of the girls smoked daily. Among children from homes where both parents were non-smokers and did not permit their children to smoke, only 9% of the boys and 11 % of the girls smoked daily. The probability of being a daily smoker can to a great extent be regarded as the additive effect of milieu predictors. When both parents smoke, older sisters and brothers smoke, best friend smokes, and the pupils are permitted to smoke, practically all 15 year olds were daily smokers. On the contrary, an environment of non-smokers and with no permission to smoke reduces the probability of being a daily smoker to almost zero.     

Joint factor analysis of the K-ABC and WISC-R with normal children

This study investigated the factor structure of the WISC-R and K-ABC for a group of 212 normal children who were tested on both instruments in counterbalanced fashion. Separate factor analyses and a joint analysis consistently produced three factors. The various analyses led to the conclusion that there is a clear-cut correspondence between the WISC-R and K-ABC factors. WISC-R Verbal Comprehension corresponded closely to K-ABC Achievement; WISC-R Perceptual Organization resembled K-ABC Simultaneous Processing; and WISC-R Freedom From Distractibility was similar to K-ABC Sequential Processing. The g factors from both instruments also correlated substantially.     

Emergence of a Gene x socioeconomic status interaction on infant mental ability between 10 months and 2 years

Recent research in behavioral genetics has found evidence for a Gene × Environment interaction on cognitive ability: Individual differences in cognitive ability among children raised in socioeconomically advantaged homes are primarily due to genes, whereas environmental factors are more influential for children from disadvantaged homes. We investigated the developmental origins of this interaction in a sample of 750 pairs of twins measured on the Bayley Short Form test of infant mental ability, once at age 10 months and again at age 2 years. A Gene × Environment interaction was evident on the longitudinal change in mental ability over the study period. At age 10 months, genes accounted for negligible variation in mental ability across all levels of socioeconomic status (SES). However, genetic influences emerged over the course of development, with larger genetic influences emerging for infants raised in higher-SES homes. At age 2 years, genes accounted for nearly 50% of the variation in mental ability of children raised in high-SES homes, but genes continued to account for negligible variation in mental ability of children raised in low-SES homes.     

An examination for construct bias in the WISC-R across socioeconomic status

The ten subtests comprising the Wechsler Intelligence Scale for Children —Revised (WISC-R) were independently factor analyzed for middle and low socioeconomic status children. Two factors described the structure of the test in both cases. These two factors corresponded quite closely to the Verbal Comprehension and Perceptual Organization factors usually reported for the WISC-R. After testing for the equivalence of covariance matrices between the two socioeconomic status groups, coefficients of congruence between the factors were calculated. These coefficients indicated equivalence in the constructs being measured across the two groups.     

Age comparative factor analysis of ability variables in adulthood and old age

The generality of ability factor structure in adulthood and old age was investigated using simultaneous maximum likelihood procedures. Data were analyzed for 198 young individuals (age range of 15–32 years), 156 younger old individuals (age range of 53–68 years), and 156 older old individuals (69–91 years). Variables were nine tests marking three ability factors: Verbal Comprehension, Sensitivity to Problems and Semantic Redefinition. Results indicated no changes in the number of factors and no psychologically important shifts in salient factor loadings. Increasingly larger factor covariances, however, were obtained in the two older groups. The results supported the generalizability of ability structures to late life at the level of factor loadings. The implications of these results for the dedifferentiation hypothesis were not clear cut. The consistency of the number of factors across age groups precluded strong support for this hypothesis, The increased factor covariances could be construed as modest support for this hypothesis, but other interpretations were possible.     

Factor structure of the Norwegian version of the WAIS-III in a clinical sample: the arithmetic problem

Confirmatory Factor Analyses (CFA) of the Wechsler Adult Intelligence Scale-III (WAIS-III) lend partial support to the four-factor model proposed in the test manual. However, the Arithmetic subtest has been especially difficult to allocate to one factor. Using the new Norwegian WAIS-III version, we tested factor models differing in the number of factors and in the placement of the Arithmetic subtest in a mixed clinical sample (n = 272). Only the four-factor solutions had adequate goodness-of-fit values. Allowing Arithmetic to load on both the Verbal Comprehension and Working Memory factors provided a more parsimonious solution compared to considering the subtest only as a measure of Working Memory. Effects of education were particularly high for both the Verbal Comprehension tests and Arithmetic.     

Concurrent and predictive validity of the Kaufman Assessment Battery for Children with a Navajo sample

The aim of this investigation was to examine the mean scores and predictive validity coefficients obtained from the Wechsler Intelligence Scale for Children-Revised (WISC-R), the Kaufman Assessment Battery for Children (K-ABC), and the Peabody Individual Achievement Test (PIAT). The K-ABC and the WISC-R were administered 1 week apart in counterbalanced order to 35 Navajo children aged 6–12$\text{1}\text{2}$ years (mean 8–9 years), followed 10$\text{1}\text{2}$ months later by administration of the PIAT. The K-ABC yielded an overall mean of 95.0, which is significantly higher than the WISC-R Full Scale IQ mean of 86.9. All WISC-R and K-ABC global scores correlated significantly except the WISC-R Verbal and K-ABC Nonverbal scales. The WISC-R Verbal and Full Scale IQs and all five K-ABC scales correlated significantly with the PIAT Total Test standard scores. However, the K-ABC Achievement scale correlated significantly higher with the PIAT Total Test than with the WISC-R Verbal and Full Scale IQs. The implications of these findings are discussed.