Data relating to prenatal lead exposure and child IQ at 4 and 8 years old in the Avon Longitudinal Study of Parents and Children

As part of the Avon Longitudinal Study of Parents and Children (ALSPAC), measures of child IQ were collected by trained psychologists. The Wechsler Pre-school and Primary Scale of Intelligence – Revised UK edition (WPPSI) was used at age 4 years in a subsample of children enrolled in ALSPAC (the Children in Focus cohort), chosen at random from the last 6 months of ALSPAC births (about 10% of the participants). At age 8 years all children enrolled in the main cohort were invited to complete a short form of the Wechsler Intelligence Scale for Children (WISC)-III ^UK. Prenatal blood lead (B-Pb) concentrations were measured by inductively-couple plasma mass spectrometry in samples from women at a median gestation age of 11 weeks. Child blood lead was measured by atomic absorption spectrometry in samples from children attending the Children in Focus clinic at age 30 months. Maternal reports at 32 weeks’ gestation were used to generate data on a range of potential confounders. The data were used to determine the associations between prenatal exposure to lead and child IQ at 4 and 8 years. The effect of child B-Pb at 3 years as a moderator of these associations was tested. (For results, please see doi:10.1016/j.neuro.2017.07.003 Taylor et al., (2017)).     

Naming skills of children born preterm in comparison with their term peers at the ages of 9 and 16 years

The linguistic abilities of children born preterm at 32 weeks' gestation or earlier at Kuopio University Hospital during 1984 to 1986 were evaluated during successive phases of a prospective study. The study protocol included the Rapid Automatic Naming test and Wechsler Intelligence Scale for Children - Revised at 9 years of age and a modified Stroop Color-Word test and the Wechsler Intelligence Scale - Revised at the age of 16 years. Fifty-one children born preterm (26 males, 25 females) and 51 age-matched and sex-matched term controls (26 males, 25 females) were studied at the age of 9 years. At the age of 16 years, 40 children born preterm (19 males, 21 females) and 31 term controls (14 males, 17 females) participated in the study. The children born preterm scored significantly lower in two naming tasks than the controls at the age of 9 years. However, there was no difference between the study groups in naming skills at the age of 16 years or in verbal IQ in either study phase. Maternal education level was not associated with naming skills. Thus, the consequences of preterm birth seem to be minor in relation to linguistic skills during school age and diminish by adolescence.     

Non-verbal learning disabilities in children with infantile hydrocephalus, aged 4-7 years: a population-based, controlled study

The aim of this population-based, controlled study was to investigate non-verbal learning disabilities (NLD) in children with infantile hydrocephalus (IH). For this purpose, the results from subtests measuring either assets or deficits within Rourke's model of NLD were analyzed. Children with myelomeningocele (MMC), intracranial tumors, or IQ < 70 were excluded. Of the 52 IH children included in the study, 46 were shunt-treated, whereas 6 were not shunted. The 44 controls were matched according to age, gender, and geographic variables. The Neuropsychological Assessment of Children (NEPSY) was administered to 52 children (age 4-7) with IH; (F = 17, M = 35), and to 44 controls (F = 17, M = 27). The tests used were classified along each of the dimensions "assets" or "deficits", according to Rourke's model of the elements and the dynamics of the NLD syndrome. Differences between sum scores for the subtests classified as "assets", versus "deficits" were significantly higher in the IH group as compared with the controls (p < 0.005). These findings are compatible with a higher frequency of NLD in the IH group, in which neurological confounding factors have been excluded. In addition, the model of the elements and the dynamics of the NLD syndrome may be useful when analyzing neuropsychological test results obtained with traditional and comprehensive test batteries.     

Family environment and cognitive abilities in girls with fragile-X syndrome

Background There remains some variance in cognitive ability that is unexplained in children with fragile‐X syndrome (FXS). Studies in typically developing children suggest that family environment might be one contributor to this unexplained variance. However, the effect of family environment in relation to cognition in atypical children with FXS has been relatively unexplored to date. Methods The present authors examined the putative genetic and environmental factors associated with cognition in a group of age‐matched children consisting of 26 females with FXS and 31 typically developing children. All subjects were administered the Wechsler Intelligence Scale for Children – Revised; and the subjects’ parents were administered the Wechsler Adult Intelligence Scale – Revised, and completed the Hollingshead Index of Social Status and the Moos & Moos Family Environment Scale. Results Using a multiple regression analytic strategy, the present authors found that family environment contributed significantly to cognitive abilities in typically developing girls, but did not have a unique contribution to cognitive abilities in girls with FXS. There was a suggestion that, for girls with FXS, socio‐economic status, a measure of sociocultural environment, was correlated with IQ. Conclusions The present study provides a basis for future research on the environmental contributions to cognitive abilities, particularly work related to verbal cognition.     

Head size and intelligence, learning, nutritional status and brain development. Head, IQ, learning, nutrition and brain

This multifactorial study investigates the interrelationships between head circumference (HC) and intellectual quotient (IQ), learning, nutritional status and brain development in Chilean school-age children graduating from high school, of both sexes and with high and low IQ and socio-economic strata (SES). The sample consisted of 96 right-handed healthy students (mean age 18.0 +/- 0.9 years) born at term. HC was measured both in the children and their parents and was expressed as Z-score (Z-HC). In children, IQ was determined by means of the Wechsler Intelligence Scale for Adults-Revised (WAIS-R), scholastic achievement (SA) through the standard Spanish language and mathematics tests and the academic aptitude test (AAT) score, nutritional status was assessed through anthropometric indicators, brain development was determined by magnetic resonance imaging (MRI) and SES applying the Graffar modified method. Results showed that microcephalic children (Z-HC < or = 2 S.D.) had significantly lower values mainly for brain volume (BV), parental Z-HC, IQ, SA, AAT, birth length (BL) and a significantly higher incidence of undernutrition in the first year of life compared with their macrocephalic peers (Z-HC > 2S.D.). Multiple regression analysis revealed that BV, parental Z-HC and BL were the independent variables with the greatest explanatory power for child's Z-HC variance (r(2) = 0.727). These findings confirm the hypothesis formulated in this study: (1) independently of age, sex and SES, brain parameters, parental HC and prenatal nutritional indicators are the most important independent variables that determine HC and (2) microcephalic children present multiple disorders not only related to BV but also to IQ, SA and nutritional background.     

Cognitive deficits in children with sickle cell disease

We tested a hypothesis that children with sickle cell disease who are completely normal by magnetic resonance imaging can still be cognitively impaired, as predicted by a model of diffuse brain injury. Fifty-four patients with hemoglobin SS (average age 10.9 years +/- 2.9 years SD) were examined with the Wechsler Intelligence Scale for Children-III (WISC-III) and were randomly matched by age, race, and gender with healthy children from the Wechsler normative database. Patients were also imaged at 1.5 Tesla with standard imaging sequences. Among 30 patients who were normal by magnetic resonance imaging, there were substantial deficits in Wechsler Full-Scale IQ, Verbal IQ, and Performance IQ (all P < .01) compared with African-American controls. The patient Wechsler Full-Scale IQ was 12.9 points lower than that of controls and decreased as a function of age (probability = .014). The findings suggest that there is diffuse brain injury in patients and that patient deficits increase with age.     

Discrepancies between IQ and memory scores in alcoholism and aging

Standardized IQ and memory tests were administered to 30 alcoholic men (7 with Korsakoff's syndrome) and 29 nonalcoholic controls between 24 and 74 years of age, in order to evaluate alcohol-related discrepancies between IQ and memory scores (including those attributable to possible premature aging). Severity of amnesia often has been defined operationally as a large discrepancy between IQ scores on the Wechsler Adult Intelligence Scale (WAIS), and scores on memory tests such as the Wechsler Memory Scale (WMS). In the context of a normal WAIS Full Scale IQ or Verbal IQ, a low WMS memory quotient (MQ) signals the possibility of anterograde memory disorder. Revised and nonrevised versions of the WAIS and WMS were given to all of the subjects. As expected, the revised versions yielded lower scores than the non-revised versions; these differences were especially prominent in the older subjects (whether or not they had a history of alcoholism) and the Korsakoff patients. Korsakoff patients demonstrated the largest discrepancies between IQ and memory scores, regardless of the tests being used. Results indicated that measures used clinically to reveal amnesia, that is, large differences between IQ scores and memory scores, were effective in any combination (the WAIS or the WAIS-R with the WMS or the WMS-R).     

Assessment of mentally retarded children with the Kaufman Assessment Battery for Children

The Wechsler Intelligence Scale for Children-Revised (WISC-R) and the Kaufman Assessment Battery for Children (K-ABC) were compared using a sample of 37 mentally retarded children (mean age = 9.75 years). The predictive validity of these instruments was examined using the Peabody Individual Achievement Test, administered 7 months later, as a criterion measure of achievement. Results revealed that the WISC-R Full Scale IQ (57.8) was significantly lower, p less than .001, than the K-ABC Mental Processing Composite (65.1). The WISC-R Verbal and Full Scale IQs correlated highly with the K-ABC Achievement Scale, which was the best predictor of PIAT Total Test scores. Implications for use of the K-ABC and WISC-R were presented.     

Neurocognitive stability in Asperger syndrome, ADHD, and reading and writing disorder: a pilot study

Boys with Asperger syndrome (n=20), attention-deficit-hyperactivity disorder (n=20), and reading and writing disorder (n=20) were followed up and retested on several neuropsychological measures 1 to 2 years after initial assessments. Wechsler Intelligence Scale for Children (WISC-III) Full Scale, Verbal, and Performance IQ scores remained stable for all diagnostic groups. Kaufman factors and 'fluid' and 'crystallized' abilities were also stable measures. Subtest stability over time, was slightly more variable. There was a tendency for the group with Asperger syndrome to deteriorate over time with respect to logical reasoning abilities. Measures of executive function/attention ('go-no-go' and 'conflict' tests) showed good test-retest stability in all diagnostic groups. This is the first study of its kind.     

Intelligence or years of education: which is better correlated with memory function in normal elderly Japanese subjects?

Background: We compared differences in intelligence and memory function between normal elderly Japanese subjects with more years of education and those with fewer years of education. We also investigated clinical and neuropsychological factors that are strongly correlated with memory function. Methods: There were 118 normal elderly subjects who underwent the Mini‐Mental State Examination, Wechsler Adult Intelligence Scale, 3rd edition (WAIS‐III), and Wechsler Memory Scale Revised. Subjects with at least 13 years of education were categorized as the H group, and those with 12 years of education or less were categorized as the L group. Results: Age and Mini‐Mental State Examination scores were not significantly different between the two groups. On the WAIS‐III, there were significant differences between the two groups in Verbal IQ and Full Scale IQ. On the Wechsler Memory Scale Revised, there were significant differences between the two groups in Visual Memory, General Memory, and Delayed Recall. Correlation coefficients between memory function and the other factors demonstrated significant but weak correlations between years of education and General Memory (R = 0.22) and between years of education and Delayed Recall (R = 0.20). Strong correlations were found between Verbal IQ and Verbal Memory (R = 0.45), between Verbal IQ and General Memory (R = 0.49), between Full Scale IQ and General Memory (R = 0.50) and between Full Scale IQ and Delayed Recall (R = 0.48). Conclusions: In normal elderly Japanese subjects, years of education weakly correlated with memory function while Verbal IQ, Full Scale IQ and Verbal Comprehension on WAIS‐III had stronger correlations with memory function. Verbal IQ and Verbal Comprehension on WAIS‐III were found to be insusceptible to the cognitive decline characteristic of Alzheimer's disease or amnestic mild cognitive impairment. Therefore, verbal intelligence, as measured by Verbal IQ and Verbal Comprehension, may be the most useful factor for inferring premorbid memory function in Alzheimer's disease or amnestic mild cognitive impairment patients.     

学龄期癫癎患儿认知功能状况与相关因素分析

目的探讨学龄期癫癎患儿的认知功能及其相关因素的关系。方法调查新近确诊的38例发作控制在75%以上且时间超过一年的学龄期癫癎患儿的临床资料,运用韦氏儿童智力量表测定所有癫癎患儿治疗前后的认知功能,同30例正常儿童进行对照,并进行统计学分析。结果癫癎患儿的智商较正常对照组明显下降(P<0.01);癫癎患儿治疗后总智商与病程、发作频率及每次发作时间呈正相关(γ=0.523,P=0.013;γ=0.432,P=0.043;γ=0.487,P=0.048),与发病年龄呈负相关(γ=-0.452,P=0.046);癫癎患儿单药治疗控制发作1年后平均智商从81.97提高到90.93,具有统计学意义(P<0.05),二药治疗平均智商从85.89提高到88.78,无统计学意义(P>0.05)。结论癫癎患儿智能存在不同程度的缺陷,与发病年龄、病程、发作频率、发作持续时间有关,药物控制癫癎发作对患儿认知功能有益。     

Role of assessment tests in the stability of intelligence scoring of pre-school children with uneven/delayed cognitive profile

Background As part of an ongoing clinical service programme for pre‐school children with developmental delay in an Asian developing country, we analysed the effect of three assessment tests, that is, Bayley Scale of Infant Development‐II, Leiter International Performance Scale – Revised and Wechsler Preschool and Primary Scale of Intelligence – Revised – Chinese, on the stability of intelligence quotient (IQ) of children from pre‐school through early childhood. Methods The participants were 313 Taiwanese pre‐school children with uneven or delayed cognitive profile and they were followed through early childhood. IQ stability was explored by different tests and among children of different clinical diagnosis: 168 children with non‐autistic intellectual disability, 73 children with autism spectrum disorder, 58 children with mixed receptive‐expressive language disorder and 14 children of other heterogeneous diagnoses. Stability of scores was evaluated using the r‐squared for Pearson's coefficients to see the correlation between initial IQ (IQ1) and follow‐up IQ (IQ2). Multiple linear regressions were also applied to see whether IQ1 had predictive ability for IQ2 and test–test difference in the total 313 children and each diagnostic subgroup. Results Results revealed that mean IQ1 was 65.8 ± 15.4 while mean IQ2 was 73.2 ± 17.9 for the total 313 children. The IQs were stable across an average follow‐up duration of 38.6 ± 22.1 month from pre‐school into early childhood. Patterns of positive correlations between IQ1 and IQ2 were noted by all the tests (r‐squared = 0.43–0.5, all P < 0.001) and in the majority of diagnostic subgroups. Multiple regressions analysis also revealed that IQ1 could predict IQ2 significantly in all the tests (all P < 0.001). Discussion After careful choice of appropriate initial test, stability of IQ in children with developmental delay was noted from pre‐school through early childhood. In addition, the translated version of cognitive assessment was valid for the required context of an Asian developing country. With the current emphasis on early identification and intervention for pre‐school children with developmental delay, this information bears merit in clinical practice.     

Value of ancillary testing in the diagnosis of pervasive developmental disorder in adults

Recently, there has been increasing interest in adults with pervasive developmental disorder (PDD) who seek general psychiatric services for various psychiatric problems. The diagnosis of PDD requires the careful collection of information about the patient's developmental history. A structured diagnostic interview is useful and should be performed, but has limitations now. The clinical value of the measurement of the Wechsler Adult Intelligence Scale, the Autism-Spectrum Quotient Japanese Version, and the Pervasive Developmental Disorders Autism Society Japan Rating Scale was demonstrated by a questionnaire survey that the authors conducted in 2010. These additional tests are useful if interpreted with caution. For example, a discrepancy between the performance intelligence quotient (IQ) and the verbal IQ in the Wechsler Adult Intelligence Scale does not by itself diagnose PDD. We examined whether the Japanese version of the National Adult Reading Test (Japanese Adult Reading Test; JART), a valid scale for evaluating pre-morbid IQ in patients with schizophrenia, and the Wechsler Adult Intelligence Scale-Revised (WAIS-R) are useful for discriminating between PDD and schizophrenia. Sixteen patients with adult PDD and 16 patients with schizophrenia matched for age, education and sex participated in this study. In addition, the two groups were matched for JART and the Global Assessment of Functioning scores. All subjects were scored on the JART and WAIS-R after giving informed consent for the study. The result was that significant diagnosis-by-IQ examination interactions were found (F [1, 30]=10.049, P=0.003). Also, the WAIS-R scores of the PDD group were higher than those of the schizophrenia group (P=0.002) when the two groups were matched for JART. In conclusion, the comparison of IQ in the PDD group and in the schizophrenia group by JART and WAIS-R might be an easy and useful method for helping to discriminate between PDD and schizophrenia. In addition, the difference in IQ scores measured by JART and by WAIS-R may be helpful in diagnosing PDD. The diagnosis of PDD in adults may be assisted by the use of these additional tests.     

A comparison of low IQ scores from the Reynolds Intellectual Assessment Scales and the Wechsler Adult Intelligence Scale-Third Edition

Twenty people with suspected intellectual disability took the Reynolds Intellectual Assessment Scales (RIAS; C. R. Reynolds & R. W. Kamphaus, 1998) and the Wechsler Adult Intelligence Scale-3rd Edition (WAIS-III; D. Wechsler, 1997) to see if the 2 IQ tests produced comparable results. A t test showed that the RIAS Composite Intelligence Index scores were significantly higher than WAIS-III Full Scale IQ scores at the alpha level of .01. There was a significant difference between the RIAS Nonverbal Intelligence and WAIS-III Performance Scale, but there was no significant difference between the RIAS Verbal Intelligence Index and the WAIS-III Verbal Scale IQ. The results raise questions concerning test selection for diagnosing intellectual disability and the use of the correlation statistic for comparing intelligence tests.     

Late effects of unilateral brain lesions sustained before and after age one

Forty-eight children with unilateral cerebral lesions, incurred before or after the first year of life, were given the Wechsler Intelligence Scale for Children, with an average delays of 4 and 8 1/2 yr for the late and early injuries, respectively. Thirty-one of their siblings were chosen as controls. Results are as follows: early and late right-hemisphere lesions significantly lower only Performance IQ. Early left lesions impair equally Verbal and Performance IQ, while late left-hemisphere lesions do not significantly affect Verbal or Performance IQ relative to controls.     

Neuropsychological profile of children with cryptogenic localization-related epilepsy and its association with age at onset

The aim of this study was to investigate the neuropsychological profile of children with cryptogenic localization-related epilepsy (CLRE). Neuropsychological evaluations were performed in 16 CLRE children and 14 children with idiopathic localization-related epilepsy (ILRE) for control within 8 months (average 2.1 months) of initial seizure. The neuropsychological tests used in this study are as follows: the Wechsler Intelligence Scale for Children-Third Edition, Wechsler Intelligence Scale for Children-Revised, and Wechsler Preschool and Primary Scale of Intelligence. Age at onset and test differed significantly between CLRE and ILRE, while the duration between onset and test and the number of seizures before test did not. No marked difference was observed in the neuropsychological profile between 2 groups; however, the discrepancy between VIQ and PIQ was significantly larger in CLRE than in ILRE. This discrepancy was negatively correlated with age at the time of seizure onset (r = -0.615, and p = 0.011). The laterality in discrepancy between VIQ and PIQ was associated with the dominance of interictal discharge. In conclusion, children with lower age at the time of seizure onset were likely to have had a larger discrepancy between VIQ and PIQ.     

Estimating premorbid general cognitive functioning for children and adolescents using the American Wechsler Intelligence Scale for Children-Fourth Edition: demographic and current performance approaches

Neuropsychologic evaluation requires current test performance be contrasted against a comparison standard to determine if change has occurred. An estimate of premorbid intelligence quotient (IQ) is often used as a comparison standard. The Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV) is a commonly used intelligence test. However, there is no method to estimate premorbid IQ for the WISC-IV, limiting the test's utility for neuropsychologic assessment. This study develops algorithms to estimate premorbid Full Scale IQ scores. Participants were the American WISC-IV standardization sample (N = 2172). The sample was randomly divided into 2 groups (development and validation). The development group was used to generate 12 algorithms. These algorithms were accurate predictors of WISC-IV Full Scale IQ scores in healthy children and adolescents. These algorithms hold promise as a method to predict premorbid IQ for patients with known or suspected neurologic dysfunction; however, clinical validation is required.     

Speech, expressive language, and verbal cognition of preschool children with cerebral palsy in Iceland

Aim The aim of this study was to describe speech, expressive language, and verbal cognition of children with cerebral palsy (CP). Method A population study included 152 Icelandic children with congenital CP (74 males, 78 females; mean age 5y 5mo, range 4y–6y 6mo). Children who spoke in sentences, phrases, or one‐word utterances were categorized as verbal. Speech was classified as normal, mild dysarthria, or severe dysarthria. Cognition was reported as IQ (Wechsler Preschool and Primary Scale of Intelligence – Revised) or developmental quotient (DQ). Results Most children (81%) had spastic CP and bilateral symptoms (76%); 74 (49%) were at Gross Motor Function Classification System (GMFCS) level I, 27% at levels II and III, and 24% at levels IV and V (p<0.001). One hundred and twenty‐eight children (84%) communicated verbally whereas 24 were nonverbal. Nonverbal status and severe dysarthria were associated with greater motor impairment (GMFCS; p<0.001). Twenty‐five children (16%) had severe dysarthria. Most (88%) of the nonverbal children had multiple disabilities compared with 18% of the verbal group (p<0.001). Median (interquartile range) verbal IQ was 93 (73–104) and performance IQ 77 (61–94; p<0.001). Sixty‐eight children (45%) had normal verbal cognition and almost a quarter of the children with severe dysarthria had a full‐scale IQ/DQ of 70. Interpretation Most children with CP express sentences and almost half of them have normal verbal IQ. Nonverbal status frequently indicates multiple impairments whereas severe dysarthria may be associated with normal cognition.     

Neuropsychological functioning in children with DSM-IV combined type Attention Deficit Hyperactivity Disorder

OBJECTIVE: To compare the global cognitive functioning and frontal lobe functioning of children with and without DSM-IV combined type Attention Deficit Hyperactivity Disorder (ADHD). METHOD: Participants were 6 to 10 year old, clinic-referred children diagnosed with combined type ADHD, who were medication na?ve; and an age (+/- 3 months) and sex matched group of children without behaviour problems. The performance of the two groups were compared on measures of intellectual functioning and tests designed to assess the functions of the frontal lobes (verbal and-non-verbal fluency, reasoning, problem solving, spatial working memory, attention). RESULTS: The children with ADHD obtained significantly lower Wechsler Intelligence Scale for Children-third edition IQ scores than controls and performed more poorly across the range of frontal lobe tests. Group differences on these tests were attenuated when IQ scores were included in the analyses as a covariate. CONCLUSIONS: Children with combined type ADHD have mild to moderate global cognitive impairment together with some impairment of functions subserved by the frontal lobes. Longitudinal studies are required to determine if the deficit in global cognitive functioning is a primary deficit or secondary to the deficit in frontal lobe functioning. The importance of neuro-psychological assessment and follow-up for children with ADHD is stressed. Study limitations relate to the generalizability of the findings and the absence of a psychiatric control group.     

Sex interaction of white matter microstructure and verbal IQ in corpus callosum in typically developing children and adolescents

BackgroundChildhood is an extremely important time for neural development that has a critical role in human intelligence. Efficient information processing is crucial for higher intelligence, so the intra- or inter-hemispheric interaction is vital. However, the relationship between neuroanatomical connections and intelligence in typically developing children, as well as sex differences in this relationship, remains unknown.MethodsParticipants were 253 typically developing children (121 boys and 132 girls) aged 5–18. We acquired diffusion tensor imaging data and intelligence using an age-appropriate version of the IQ test; Wechsler Intelligence Scale for Children (WISC) or Wechsler Adult Intelligence Scale (WAIS). We conducted whole-brain multiple regression analysis to investigate the association between fractional anisotropy (FA), which reflects white matter microstructural properties, and each composite score of IQ test (full-scale IQ, performance IQ, and verbal IQ).ResultsFA was positively correlated with full-scale IQ in bilateral inferior occipitofrontal fasciculus, genu, and splenium of corpus callosum (CC). FA in the right superior longitudinal fasciculus, bilateral inferior longitudinal fasciculus, and splenium of CC were also positively correlated with performance IQ. Furthermore, we found significant sex interaction between FA in the CC and verbal IQ. FA was positively correlated in boys, and negatively correlated in girls.ConclusionResults suggest that efficient anatomical connectivity between parietal and frontal regions is crucial for children’s intelligence. Moreover, inter-hemispheric connections play a critical role in verbal abilities in boys.