Brief report : the level and nature of autistic intelligence revisited

Owing to higher performance on the Raven’s Progressive Matrices (RPM) than on the Wechsler Intelligence Scales (WIS), it has recently been argued that intelligence is underestimated in autism. This study examined RPM and WIS IQs in 48 individuals with autism, a mixed clinical (n = 28) and a neurotypical (n = 25) control group. Average RPM IQ was higher than WIS IQ only in the autism group, albeit to a much lesser degree than previously reported and only for individuals with WIS IQs <85. Consequently, and given the importance of reliable multidimensional IQ estimates in autism, the WIS are recommended as first choice IQ measure in high functioning individuals. Additional testing with the RPM might be required in the lower end of the spectrum

Genetic Covariance Structure of Reading, Intelligence and Memory in Children

This study investigates the genetic relationship among reading performance, IQ, verbal and visuospatial working memory (WM) and short-term memory (STM) in a sample of 112, 9-year-old twin pairs and their older siblings. The relationship between reading performance and the other traits was explained by a common genetic factor for reading performance, IQ, WM and STM and a genetic factor that only influenced reading performance and verbal memory. Genetic variation explained 83% of the variation in reading performance; most of this genetic variance was explained by variation in IQ and memory performance. We hypothesize, based on these results, that children with reading problems possibly can be divided into three groups: (1) children low in IQ and with reading problems; (2) children with average IQ but a STM deficit and with reading problems; (3) children with low IQ and STM deficits; this group may experience more reading problems than the other two

Normative Values for 18-30 Age Group of Benton Visual Retention Test Scores and Pre-morbid Intelligence Quotients: New Data Comparisons for Diagnosing Memory and Visual Spatial Deficits in Alzheimer's Disease and Stroke

The Benton Visual Retention Test (BVRT) is a well known test used to assess visual memory deficits and visual spatial abilities in patients. Normative data for the 18-30 age group is not presently covered thoroughly; hence, this study continues the work of previous series that examined data comprising BVRT scores, intelligence quotients (IQ), anxiety and depression levels, and gender effects. Correlations between pre-morbid estimates of IQ across different BVRT administrations were examined and discussed in order to compile a database of new data comparisons for this age group

A study of the differences between boys and girls and between boys and girls of different IQ levels, on a certain selection of subtests of the Wechsler Intelligence Scale for children

Research and study aimed at understanding the intellectual structure and functioning of the retarded and the slow learner has been minimal. One of the most significant contributions in this direction has been the previously mentioned study of WISC subtest scores by Baumeister and Bartlett which discerned the Stimulus Trace factor appearing in certain of the scores of retardates but not in those of normals. The present study was undertaken primarily to examine sex differences between particular subtest scores of the so-called Stimulus Trace factor in a specific group of retarded and slow learners in a particular locale. More specifically, the intentions of this study were to answer the following questions: 1. Is there a difference between the sexes in the total group on the Full Scale IQ\u27s, Verbal IQ\u27s, and Performance IQ\u27s? 2. Is there a difference between the sexes in the total group on the scores of the subtests which are related to the Stimulus Trace factor? 3. Is there a difference between the sexes in the IQ group below 69 on Full Scale IQ\u27s, Verbal IQ\u27s, and Performance IQ\u27s? 4. Is there a significant difference between the sexes in the IQ group below 69 on certain selected subtests of the WISC? 5. Is there a difference between the sexes in the IQ group from 70 to 79 on Full Scale IQ\u27s, Verbal IQ\u27s, and Performance IQ\u27s? 6. Is there a significant difference between the sexes in the IQ group from 70 to 79 on certain selected subtests of the WISC? 7. Is there a difference between the sexes in the IQ group from 80 to 89 on Full Scale IQ\u27s, Verbal IQ\u27s, and Performance IQ\u27s? 8. Is there a significant difference between the sexes in the IQ group from 80 to 89 on certain selected subtests of the WISC

A comparison of the WISC-IV and WAIS-III in the low IQ range

A diagnosis of intellectual disability (ID), mental retardation (MR) or Learning Disabilities (LD) can have a major effect on people’s lives. On the positive side it can provide services, finance, help in schools, and can even prevent the recipient from being executed (Flynn 2006; Flynn 2007; Schalock et al 2007). On the negative side it is may be regarded as a stigmatizing label that an individual may seek to avoid (Baroff 1999). Currently a necessary though not sufficient part of the diagnosis of ID is having an IQ below a specified figure, usually 70, or two standard deviations (SDs) below the norm (American Association on Mental Retardation, 2002; American Psychiatric Association 2000; Department of Health 2001; British Psychological Society 2001). This specification of a specific IQ figure implies that an individual has a “true IQ” that can be measured. If different IQ tests systematically measure either higher or lower than other tests it would raise the question as to which IQ test was providing the best estimate of an individual’s true IQ. In the absence of a test that is clearly an accurate measure of true IQ, the best that could be done would be to decide which of the many IQ tests is likely to be the most accurate, and take that as the “gold standard” assessment against which other assessment should be compared. The Wechsler assessments, the WISC-IV and the WAIS-III should have a good claim to be regarded as the gold standard assessments. However, for these assessments to be accepted as gold standard assessments for the diagnosis of ID, it requires that they should produce equivalent IQ scores in the low ability range. We compared the WISC-IV and WAIS-III on a group of 16-year-olds in special education. Sixteen being the age group at which both assessments can be used. Both the WISC-IV and the WAIS-III were given to seventeen 16-year-olds (9 female and 8 male) attending local special schools in counterbalanced order. The results were as follows: WISC-IV WAIS-III Diff r Mean Full Scale IQ 53.00 64.82 11.82 .93 In spite of a very high correlation between the two scales there was a highly significant difference between the mean FS IQ on each scale of nearly 12 points (P<.001 on t-test); none of the participants in the study scored higher on the WISC-IV than they did on the WAIS-III. It is therefore clear that either one or both of these assessments is failing to produce an accurate measure of an individuals true IQ. As the degree to which either assessment is in error is not known, it is clearly possible that either the WISC-IV is systematically underestimating true IQ by up to 12 points, or the WAIS-III is systematically overestimating true IQ by 12 points or both assessments are making systematic errors of less than 12 points. Clearly this has implications for the use of a specified IQ figure as a diagnostic criterion for ID. Summary of abstract The WISC-IV and WAIS-III were given to seventeen 16-year-olds in special education in counterbalanced order. The mean FS IQ on the WISC-IV was 53.00 and on the WAIS-III it was 64.82 a difference of nearly 12 points. The correlation between the two assessments was .93. It is therefore clear that either one or both of these assessments is failing to produce an accurate measure of an individuals true IQ

Childhood IQ and risk of bipolar disorder in adulthood: prospective birth cohort study

Background: Intellectual ability may be an endophenotypic marker for bipolar disorder. Aims: Within a large birth cohort, we aimed to assess whether childhood IQ (including both verbal IQ (VIQ) and performance IQ (PIQ) subscales) was predictive of lifetime features of bipolar disorder assessed in young adulthood. Method: We used data from the Avon Longitudinal Study of Parents and Children (ALSPAC), a large UK birth cohort, to test for an association between measures of childhood IQ at age 8 years and lifetime manic features assessed at age 22–23 years using the Hypomania Checklist-32 (HCL-32; n=1881 individuals). An ordinary least squares linear regression model was used, with normal childhood IQ (range 90–109) as the referent group. We adjusted analyses for confounding factors, including gender, ethnicity, handedness, maternal social class at recruitment, maternal age, maternal history of depression and maternal education. Results: There was a positive association between IQ at age 8 years and lifetime manic features at age 22–23 years (Pearson's correlation coefficient 0.159 (95% CI 0.120–0.198), P&#62;0.001). Individuals in the lowest decile of manic features had a mean full-scale IQ (FSIQ) which was almost 10 points lower than those in the highest decile of manic features: mean FSIQ 100.71 (95% CI 98.74–102.6) v. 110.14 (95% CI 107.79–112.50), P&#62;0.001. The association between IQ and manic features was present for FSIQ, VIQ and for PIQ but was strongest for VIQ. Conclusions: A higher childhood IQ score, and high VIQ in particular, may represent a marker of risk for the later development of bipolar disorder. This finding has implications for understanding of how liability to bipolar disorder may have been selected through generations. It will also inform future genetic studies at the interface of intelligence, creativity and bipolar disorder and is relevant to the developmental trajectory of bipolar disorder. It may also improve approaches to earlier detection and treatment of bipolar disorder in adolescents and young adults

Impairment in movement skills of children with autism spectrum disorders

We undertook this study to explore the degree of impairment in movement skills in children with autistic spectrum disorders (ASD) and a wide IQ range. Movement skills were measured using the Movement Assessment Battery for Children (M-ABC) in a large, well defined, population-derived group of children (n=101: 89 males,12 females; mean age 11y 4mo, SD 10mo; range 10y-14y 3mo) with childhood autism and broader ASD and a wide range of IQ scores. Additionally, we tested whether a parent-completed questionnaire, the Developmental Coordination Disorder Questionnaire (DCDQ), was useful in identifying children who met criteria for movement impairments after assessment (n=97 with complete M-ABCs and DCDQs). Of the children with ASD, 79% had definite movement impairments on the M-ABC; a further 10% had borderline problems. Children with childhood autism were more impaired than children with broader ASD, and children with an IQ less than 70 were more impaired than those with IQ more than 70. This is consistent with the view that movement impairments may arise from a more severe neurological impairment that also contributes to intellectual disability and more severe autism. Movement impairment was not associated with everyday adaptive behaviour once the effect of IQ was controlled for. The DCDQ performed moderately well as a screen for possible motor difficulties. Movement impairments are common in children with ASD. Systematic assessment of movement abilities should be considered a routine investigation

A Statistical Classification on a Mixture Distribution of Intelligence Quotients and Severe Mental Retardation

Main content of this paper is to classify IQ individuals into two categories of normal and abnormal groups. It is too difficult to divide IQ individuals into two groups of normal IQ group and abnormal group because of sparse number of cases with mental retardation. Therefore, we examined a normality of 1673 IQ individuals, but a significant difference was noted for the IQ data. The lowest three mentally retarded cases of less than or equal to 59 IQ score were excluded, the IQ data then fitted to a normal distribution well. The critical value which minimizes the probability of classification is obtained on the basis on an approximate technique with regard to normality. An approximate probability of misclassification for individuals at random from mixture of two normal populations is 25.5%

発達障害の知的構造に関する研究─ 広汎性発達障害と注意欠陥障害 ─

The purpose of this paper is to examine the characteristics of the intellectual structure by conducting WISC －Ⅲ intelligence test for 41 patients, consisting of 20 of pervasive developmental disorder and 21 of attention deficit disorder. The examination is to analyze general intellectual developmental,　general level of test group index, a　difference in ability between linguistic IQ and physical IQ, a difference in ability between index numbers among test groups, and differences in level and evaluations at low level examination. The result shows that intellectual level for the group of the developmental disorder is in the middle stage, and physical IQ is superior to that of linguistic IQ. In terms of the intellectual ability, both groups show high ability of perceptive integration, but itis remarkable that both processing speed of the pervasive developmental disorder group and attention memory ability of the attention deficit disorder group are low．Also in terms of the intellectual structure in an individual, there are big differences between linguistic IQ and physical IQ, between index numbers amongtest groups, and evaluations at low level examination, which makes it clear thatthere is imbalance in intellectual structure, and that there are peculiarity inintellectual quality and development stage

Intelligence quotient–adjusted memory impairment is associated with abnormal single photon emission computed tomography perfusion

Cognitive reserve among highly intelligent older individuals makes detection of early Alzheimer's disease (AD) difficult. We tested the hypothesis that mild memory impairment determined by IQ-adjusted norms is associated with single photon emission computed tomography (SPECT) perfusion abnormality at baseline and predictive of future decline. Twenty-three subjects with a Clinical Dementia Rating (CDR) score of 0, were reclassified after scores were adjusted for IQ into two groups, 10 as having mild memory impairments for ability (IQ-MI) and 13 as memory-normal (IQ-MN). Subjects underwent cognitive and functional assessments at baseline and annual follow-up for 3 years. Perfusion SPECT was acquired at baseline. At follow-up, the IQ-MI subjects demonstrated decline in memory, visuospatial processing, and phonemic fluency, and 6 of 10 had progressed to a CDR of 0.5, while the IQ-MN subjects did not show decline. The IQ-MI group had significantly lower perfusion than the IQ-MN group in parietal/precuneus, temporal, and opercular frontal regions. In contrast, higher perfusion was observed in IQ-MI compared with IQ-MN in the left medial frontal and rostral anterior cingulate regions. IQ-adjusted memory impairment in individuals with high cognitive reserve is associated with baseline SPECT abnormality in a pattern consistent with prodromal AD and predicts subsequent cognitive and functional decline