WISC-R IQ Research Articles

Childhood IQ and Adult Mental Disorders: A Test of the Cognitive Reserve Hypothesis

Cognitive reserve has been proposed as important in the etiology of neuropsychiatric disorders. However, tests of the association between premorbid IQ and adult mental disorders other than schizophrenia have been limited and inconclusive. The authors tested the hypothesis that low childhood IQ is associated with increased risk and severity of adult mental disorders. Participants were members of a representative 1972-1973 birth cohort of 1,037 males and females in Dunedin, New Zealand, who were followed up to age 32 with 96% retention. WISC-R IQ was assessed at ages 7, 9, and 11. Research diagnoses of DSM mental disorders were made at ages 18, 21, 26, and 32. Lower childhood IQ was associated with increased risk of developing schizophrenia spectrum disorder, adult depression, and adult anxiety. Lower childhood IQ was also associated with greater comorbidity and with persistence of depression; the association with persistence of generalized anxiety disorder was nearly significant. Higher childhood IQ predicted increased risk of adult mania. Lower cognitive reserve, as reflected by childhood IQ, is an antecedent of several common psychiatric disorders and also predicts persistence and comorbidity. Thus, many patients who seek mental health treatment may have lower cognitive ability; this should be considered in prevention and treatment planning.

Ictal and interictal EEG abnormalities in ADHD children recorded over night by video-polysomnography

In this paper we explore the prevalence of ictal and interictal epileptiform discharges (IEDs) and sleep disorders in ADHD children referred to a sleep clinic for all night video-PSG. Forty-two ADHD outpatients (35 males and 7 females) underwent video-PSG and a behavioural/neuropsychological assessment. Spearman correlation coefficients (p<0.05 criterion level) were used to assess the association between cognitive, behavioural, clinical (co-morbidity), sleep (sleep efficiency) and EEG (seizures, IEDs, localization of IEDs foci) variables. Sleep disorders were found in 86% of ADHD children; among these, 26% had RLS. 53.1% of ADHD children had IEDs (28.2% centro-temporal spikes, 12.5% frontal spikes, 9.3% temporal-occipital spikes and 2.3% generalized S-W). Nocturnal seizures were recorded in three patients: two with atypical interictal rolandic spikes and one with left frontal slow abnormalities. A significant relationship (p<0.05) emerges between nocturnal seizures and WISC-R IQ score and visual-spatial memory test and between some cognitive variables and interictal rolandic spikes. High levels of inattention, impulsivity/hyperactivity and oppositional behaviours were related (p<0.01 or 0.05) with Restless Leg Syndrome diagnosis. In conclusion, ADHD is a condition often associated with EEG epileptiform abnormalities. Seizures/IEDs presence seems to play a role on cognitive abilities, conversely sleep disorders have a stronger impact on behavioural rather than cognitive indicators.

Prediction of independence and intelligence at birth in meningomyelocele

The aim of this research is to compute a prediction of the future intelligence of every neonate with a meningomyelocele (MMC) on the day of birth to inform the parents. Earlier research revealed that the variables ventricle size, open arch above vertebra lumbar 3, a very small or a very large head can be attended by an IQ below 85 points: the turning point between dependence and independence. Until now no research has been done combining the values of influencing variables in one equation. Our study used the equation of multiple longitudinal linear regression. For reference, data from the files of 148 neonates born in the years 1960-1980 were compared with those of Dutch children sampled by Verger. The working hypothesis that the IQ level is directly related to congenital deformities of the nervous system needs to be tested. As standard the values of variables at birth, the head circumference and length, the size of the ventricles and the highest open vertebral arch, are to be used. The Wisc-R of the MMC cohort had a mean of 84 points and 55% had an IQ above 85. The correlation computation of the values of all available variables with the values of the measured Wisc-R revealed the significance of the neuroanatomical variables, size of ventricle and level of the highest open vertebral arch and for the anthropomorphic variables Length and Length/Circumference. To establish the relationship between the Wisc-R value and the values of the significant variables an equation with the multiple linear regression method was used. The measured IQ is made dependent on the significant variables size of ventricle, level of highest open arch and quotient Length by Circumference. This equation produces a value called predicted IQ. The predicted IQ was 92%, the same or nearly the same as the measured Wisc-R IQ. This conformity of the measured IQ and the predicted IQ proves the possibility of using these birth data for prediction.

Long-term psychological outcome of children after surgery for transposition of the great arteries.

To assess the psychological consequences of a single congenital heart defect, we tested intellectual function, self-perception, "body image", child psychiatric symptoms and the family climate in 21 boys and 10 girls, at a mean age of 13.2 y, on average 11.5 y after surgery for transposition of the great arteries. Where applicable, test norms were used for comparison. WISC-R IQ tended to be slightly lower than that of the general population. Self-perception, as reflected on the "I think I am" test, was normal. "Body image" as measured by the "Draw-a-man" test was poor in the boys, but did not show a relationship with any other test tapping mental health. Six children (19%) had clinically significant child psychiatric symptoms, which is slightly more than expected, and were overrepresented in patients with poorer cardiac function. Five of these represented "internalizing" disorders. The patients' families scored higher than expected on the family climate "chaos" subscale, which has been demonstrated to be associated with the development of psychiatric symptoms. Overall, however, the children and their families were regarded as socially and psychologically well-functioning.

Comparison of WISC-R and WISC-III Scores of Urban Exceptional Students

WISC-R IQs and WISC-III IQs of 65 urban, exceptional students who underwent a 3-yr. reevaluation were compared. Primary questions concerned (a) mean differences in scores between respective WISC-R and WISC-III scales and subtests and (b) the relationships among scores on WISC-R and WISC-III scales and subtests. Analysis indicated that mean scores on the WISC-III scales were significantly lower than those on the WISC-R scales. Among the subtests, WISC-III IQs were significantly lower than WISC-R IQs on Similarities, Comprehension, and Coding. Intercorrelations computed between all Wechsler scales' IQs indicated substantial conceptual overlap (Full Scale IQ = .88, Verbal IQ = .86, Performance IQ = .82). The utility of the WISC-III in the placement process was supported; however, the changes on the WISC-III scales and subtests are such that caution must be exercised in the reclassification of exceptional students.

No association between general cognitive ability and the A1 allele of the D2 dopamine receptor gene.

Berman and Noble (1995) reported significantly reduced visuospatial performance in children with the TAQI A1 allele of the D2 dopamine receptor (DRD2) gene. Given that visuospatial performance loads highly on an unrotated principal component indexing general cognitive ability, we tested the association between DRD2 and WISC-R IQ comparing 51 high-IQ, 51 average-IQ, and 35 low-IQ children in the IQ Quantitative Trait Loci (QTL) Project. No statistically significant association between the TAQI A DRD2 alleles and IQ was found. Given that a statistically significant portion of genetic variance for specific cognitive abilities is independent of general cognitive ability, it is possible that the TAQI DRD2 association is specific to visuospatial performance and independent of general cognitive ability.

DNA markers associated with general and specific cognitive abilities

Multivariate quantitative genetic research suggests a hierarchical model of cognitive abilities where genetic effects are largely general, cutting across most cognitive abilities. Some genetic effects, however, are specific to certain cognitive abilities. These results lead to a hypothesis for molecular genetic research: Although most genes associated with one cognitive ability will be related to other cognitive abilities, some genes will be specific to a particular cognitive ability. The current research explored this hypothesis in an analysis of data in specific cognitive abilities from 86 children from 6 to 12 years of age from a larger allelic association study of general cognitive ability. Eight DNA markers were entered simultaneously in separate multiple regression analyses predicting each of four specific cognitive ability factors (Verbal, Spatial, Perceptual Speed, Memory), as well as WISC-R subtest scores. Four marjers (CTGB33, EST00083, HLA, and SOD2) showed similar effects across the cognitive ability scales, suggesting that they are related to general cognitive ability ( g). These associations became negligible when the effects of ‘ g’ (WISC-R IQ) were removed. Three markers (ADH5, DM, and NGFB) continued to be significantly associated with specific cognitive ability scales after the effects of ‘ g’ were removed. Although preliminary, these molecular genetic results support the hierarchical model predicted by quantitative genetic research.

Memory and Processing Speed in Preterm Children at Eleven Years: A Comparison with Full-Terms

This study examined the effects of prematurity on 11-year-olds' performance on 2 specific aspects of cognition--memory and processing speed, using a new computer-administered battery, the Cognitive Abilities Test (CAT: Detterman). Preterms performed more poorly than their full-term controls on all memory tasks; this relative deficit was associated with the presence and severity of neonatal Respiratory Distress Syndrome (RDS). Preterms were also slower on selected aspects of processing speed but not on motor speed. Memory and processing speed, taken together, accounted for much of the 10-point difference in WISC-R IQ between groups.

Can WISC-R IQ values be computed validly for learning-disabled children?

Prior research demonstrated that the relationships between age and neuropsychological test scores are much weaker in brain-damaged adults and children than in non-brain-damaged subjects It appears that the effects of brain damage on test scores are sufficiently strong to diminish the influence of age and education Similar results have been found with learning-disabled children The present study evaluated the effect of age adjustments on WISC-R IQ values and subtest scores The results suggest that conventional scoring of the WISC-R, which requires an age adjustment to obtain the IQ, underestimates the IQs especially of older LD children, apparently reflecting the learning-disabled child's limited rate of acquisition of intellectual abilities with advancing age.

Differences between WISC-III and WISC-R IQs: A Preliminary Investigation

Differences between WISC-III and WISC-R IQs of 257 children (1 18 with Specific Learning Disability, 79 with Mental Retardation, and 60 who were not classified as disabled) were examined. As anticipated, the WISC-III and WISC-R IQs were highly correlated, ranging from .84 for the Full Scale IQs to .80 for the Performance IQs. The WISC-III Full Scale, Verbal, and Performance IQs were 7.2, 5.8, and 7.5 points lower than corresponding WISC-R values. The size of the difference between WISC-III and WISC-R IQs was correlated significantly with WISC-R (r = .34) and WISC-III (r = -.23) IQs. Differences in the size of the IQ drop were in part a function of disability group membership: Students with learning disabilities differed in the likelihood of increases and decreases in IQs in comparison to students with mental retardation. Sex was unrelated to the size of the IQ drop. Amount and direction of change were predicted by subtest scores. Importantly, high Object Assembly and Coding scores were primary factors in predicting increases in IQ, and higher Vocabulary scores predicted decreases in IQ.

Relationship of the WISC-III and WISC-R for Students with Specific Learning Disabilities and Mental Retardation

The relationship between WISC-R IQs and WISC-III IQs was examined in two samples of students with disabilities. One sample ( n = 64) consisted of students with specific learning disabilities (SLD); the other sample ( n = 55) consisted of students with mental retardation (MR). All students were enrolled in special education classes and were undergoing routine three-year reevaluations. With the exception of the correlation of Performance IQs for students with MR, which was nearly identical to the correlation reported in the WISC-III manual, the correlations between the WISC-R and WISC-III IQs were lower than those reported in the WISC-III manual. In addition, Verbal, Performance, and Full Scale IQs on the WISC-III were significantly lower than the previously obtained scores on the WISC-R for both students with SLD and those with MR. These differences were generally consistent with the differences reported in the WISC-III manual.

Comparison of different indices of dietary control in phenylketonuria

Ten different indices of dietary control (IDCs) applied frequently to investigate compliance of phenylketonuric patients were calculated for a set of blood phenylalanine levels for 98 patients in the German Collaborative Study of Children Treated for Phenylketonuria during their first 9 years of life. The results were compared for similarities and differences. Cluster analysis of longitudinal phenylalanine data was introduced to analyse phenylalanine blood levels independent of a priori defined criteria of classification. Three groups of good, intermediate and poor long-term dietary control were identified. Internal validation of the IDCs was corroborated by the high inter-correlations of the indices. External validity was determined by the inter-relations of the WISC-R IQ and the IDCs. The different algorithms of IDCs suggest different clinical conclusions. To facilitate comparisons of results of future research, IDCs should be standardized.

Cognitive and psychosocial outcome after head injury in children

Abstract Neuropsychological and psychosocial assessment of 58 Victorian and South Australian school-aged children who sustained a closed head injury was carried out immediately postinjury and at 6 months follow-up. For those children whose head injury was defined as mild (length of coma less than 1 hour) outcome on all variables was good at both time points. Children with moderate to severe injury (length of coma greater than 1 hour) had lower WISC-R IQ scores at both time points and were particularly poor on reading and spelling measures. There was no improvement over time on the academic measures. Family and parental functioning was in the normative range and, although some children showed a clinical level of behaviour problems, there was no consistency in their clinical status over time nor across parent and teacher informants. Our results suggest that there are no particular concerns for the long-term outcome of mildly head-injured children but that cognitive and school learning problems for moderate ...

Validity of IQ-Achievement Discrepancy Criteria for Identifying Learning Disabilities

IQ-achievement discrepancy criteria identified 24 children with learning disabilities (LD) having a lower Verbal-higher Performance (LV-HP) WISC-R IQ profile and 33 children with slower learning (SL). The majority of children were white males of lower to middle-class background and ranged in age from 77 to 159 months. Except for predetermined Performance scale group differences, children with LD were not found to be otherwise distinguished by differences on WISC-R subtest scores, subtest scatter, or variation among Kaufman and Bannatyne category scores. Only one of the WISC-R profile differences that was an advantage for the children with LD satisfied test criteria for clinical significance. None of the differences predicted their reading, spelling, or aritlunetic achievement. Results suggest that children who are differentially identified as LV-HP LD or SL based on IQ achievement discrepancy criteria may not be distinguishable on any other aspects of their WISC-R profile that are related to their basic academic performance.

A 3-Year Comparison Study of WISC-R and WISC-III Iq Scores for a Sample of Special Education Students

The purpose of this study was to compare the Wechsler scores for the same group of students after a 3-year interval. A sample of 84 regular and special education students were tested first on the WISC-R and then 3 years later on the WISC-III. Scores were broken up into five score subgroups from lowest to highest. More WISC-III scores appeared in lower IQ ranges, whereas fewer WISC-III scores appeared in higher IQ ranges. It was surmised that the WISC-III was more difficult at the higher IQ ranges and less difficult at the lower IQ ranges. WISC-III Performance scores displayed more (lower) differences between administrations, whereas the Verbal scores, which were higher, showed more variability. Researchers concluded that practicing psychologists might be more inclined to place students in classes for the educable mentally retarded (EMR) based on the effects of lower Performance Scale scores than on Full Scale IQs.

Correlations between WISC-R Subtests and Scales of the Personality Inventory for Children

Data were collected from files of 129 children who had been administered the WISC-R and whose mothers had completed the Personality Inventory for Children. A prior high correlation between the Somatic Concern scale and WISC-R Third Factor was not replicated, but the cognitive triad of the Personality Inventory for Children correlated -.49 to -.27 with all the WISC-R IQs. Comparing a two-subtest (Arithmetic, Digit Span) Third Factor versus the traditional three-subtest triad produced comparable results, supporting the redefined Third Factor of the WISC-III.

WISC—R IQ Estimates from the Luria-Nebraska Neuropsychological Battery

Multiple regression equations predicting WISC-R IQs from Luria-Nebraska T scores and subjects' chronological age were developed and cross-validated on a total sample of 152 adolescent psychiatric patients. Data from a randomly drawn subsample of 100 subjects were entered into three stepwise multiple-regression analyses to derive equations predicting WISC-R IQs. These equations were applied to the remaining subsample (n = 52) as were the equations developed by McKay, et al. (1981) for estimating adult WAIS IQs. Mean differences, correlations, and classification hit rates between the two sets of predicted IQs and the actual WISC-R IQs were examined. Findings were similar to those of previous studies examining the predictive relationship between the Luria-Nebraska and adult intelligence. As expected, chronological age entered significantly into all three stepwise multiple-regression analyses. The newly derived equations had significantly higher correlations with the WISC-R for Verbal and Full Scale IQs and significantly better predictive accuracy for Full Scale IQ. Rates of IQ misclassification warrant caution in the use of these methods, but it is concluded that the equations derived here predict about as well as do short forms of the WISC-R.

Long-term cerebral effects of CNS chemotherapy in children with acute lymphoblastic leukemia.

Fifteen 7-16-year-old patients, treated in 1981-1984 for acute lymphoblastic leukemia (ALL) in first complete remission, were studied. As a central nervous system prophylaxis, all the children were treated with repeated methotrexate (MTX) instillations, but none were irradiated. The study protocol included magnetic resonance (MR) and a battery of neuropsychological tests. Small, punctate white-matter lesions were found by MR in eight children, probably minor vascular lesions. All the children were within normal intelligence range with a mean total WISC-R IQ of 109. Minor neuropsychologic problems were found in two patients, while one child showed a more extensive specific learning disorder in school.

Comparison of the Peabody Picture Vocabulary Test—Revised and the Wechsler Intelligence Scale for Children—Revised for a Referred Population

Comparisons were made between the PPVT-R and WISC-R with 59 school-aged students (25 females, 34 males) referred for academic underachievement. Pearson product moments (r) and related t-tests were employed in the data analysis. The sample ranged in age from 6-2 to 15-5, with a mean age of 10-1, and SD=2.8. There were no significant differences between PPVT-R standard scores and WISC-R IQs. PPVT-R scores correlated significantly (p&lt;.001) with WISC-R Verbal subtest scores. Implications of these findings for the use of the PPVT-R are discussed.

Concurrent validity of the school problem screening inventory for behavior-disordered students

This study investigated the relationship between the School Problem Screening Inventory, Fifth Edition (SPSI) and the Bristol Social Adjustment Guides (BSAG) and the WISC-R. Subjects were 43 junior high school students enrolled in residential or day-treatment programs at a treatment center for adolescents with behavior problems. The results showed the SPSI Behavior Disorder-undercontrolled and overcontrolled scores to be moderately correlated with the BSAG Overreaction and Under reaction scores, respectively. The SPSI Learning Disability and the Mental Retardation scores were found to be moderately correlated negatively with the WISC-R IQs. The findings lend support to the concurrent validity of the SPSI.