A comparison of WISC-IV and SB-5 intelligence scores in adolescents with autism spectrum disorder

Concurrent validity of intelligence assessments in children with developmental disabilities in an Asian setting: Comparison of the Kaufman brief intelligence test - Second edition with the Wechsler Intelligence Scales

BACKGROUND

This study was carried out to compare the concurrent validity of the Kaufman Brief Intelligence Test - Second Edition (KBIT-2) with that of two Wechsler Intelligence Scales (Wechsler Intelligence Scale for Children - Fifth Edition (WISC-V) and the Wechsler Preschool and Primary Scale of Intelligence - Fourth Edition (WPPSI-IV)) in an Asian setting.

METHODS

A retrospective study reviewed the medical records of 101 children with developmental disorders who were being followed up at a tertiary child development unit. Pearson product moment correlation coefficients were calculated between the KBIT-2 and Wechsler assessment scores. Simple regression analysis was used to calculate standard errors of estimation to assess the accuracy of predicting Wechsler scores using KBIT-2 scores.

RESULTS

A strong positive correlation was observed between KBIT-2's Intelligence Quotient (IQ) Composite and WISC-V's Full-Scale IQ (FSIQ) scores (r = 0.722, p < 0.01). KBIT-2 IQ composite scores showed a moderately strong positive correlation with WPPSI-IV FSIQ scores (r = 0.648, p < 0.01). Simple regression analysis showed that KBIT-2 scores tended to underestimate or overestimate the Wechsler scores, with the highest variability seen in KBIT-2's Non-Verbal IQ and Wechsler's Fluid Reasoning Index scores (error limits: -53.1 to 39.7).

CONCLUSION

Our study demonstrates that KBIT-2 has good concurrent validity when compared to other IQ tests such as the Wechsler scales, and it suggests that KBIT-2 is a good screening tool for assessing intelligence in a group of children with developmental disabilities. Further studies are needed to determine whether KBIT-2 can be used for the purpose of diagnostic decision-making or special education program placement.

Language Abilities are Associated with Both Verbal and Nonverbal Intelligence in Children on the Autism Spectrum

Intellectual abilities factor into levels of functioning used to characterize autism. Language difficulties are highly prevalent in autism and may impact performance on measures of intellectual abilities. As such, nonverbal tests are often prioritized in classifying intelligence in those with language difficulties and autism. However, the relationship between language abilities and intellectual performance is not well characterized, and the superiority of tests with nonverbal instructions is not well established. The current study evaluates verbal and nonverbal intellectual abilities in the context of language abilities in autism and the potential benefit of tests with nonverbal instructions. Participants were 55 children and adolescents on the autism spectrum who underwent a neuropsychological evaluation as part of a study examining language functioning in autism. Correlation analyses were performed to examine relations between expressive and receptive language abilities. Language abilities (CELF-4) were significantly correlated with all measures of both verbal (WISC-IV VCI) and nonverbal intelligence scores (WISC-IV PRI and Leiter-R). There were no significant differences between nonverbal intelligence measures with verbal or nonverbal instructions. We further discuss the role of assessment of language abilities in interpreting results of intelligence testing in populations with higher prevalence of language difficulties.

Comparison of the Wechsler Preschool and Primary Scale of Intelligence-Third Edition and the Leiter-R Intellectual Assessments for Clinic-Referred Children

A review of clinical records was conducted for children with developmental, emotional, and behavioral difficulties who were assessed with both the Wechsler preschool and primary scale of intelligence-third edition (WPPSI-IIICDN; Wechsler, 2004) and the Leiter international performance scale-revised (Leiter-R; Roid & Miller, 1997) within the same psychological evaluation. Forty children, ages 3-7, were included in this study. Pearson correlations showed that the IQ scores of the two instruments are strongly related (r > .70; p < .001). However, paired t-tests showed that overall Leiter-R scores (M = 99.03) were significantly higher than WPPSI-IIICDN scores (PIQ; M = 82.28, FSIQ; M = 75.24) (p < .001). The discrepancies between the instrument's scores were clinically important as the use of only one of the two instruments could result in misclassification of child intellectual ability. These results should prompt professionals working with this clinical population to be cautious when using results from a single instrument in a child's intellectual evaluation.

Diversity of Intelligence is the Norm Within the Autism Spectrum: Full Scale Intelligence Scores Among Children with ASD

Although previous research helped to define differences in intelligence between neurotypicals and those with ASD, results were limited by small sample sizes or restricted subtests. Using data from the NIMH Data Archive, this study examined the intelligence of children with ASD (N = 671). Results demonstrate an average standard deviation of 25.75, which is 1.72 times greater than that of the normative sample for the WISC-III. Moreover, students with ASD are 12 times more likely than the general population of students to score within the intellectual disability range, but are also 1.5 times more likely to score in the superior range, suggesting that more students with ASD should be considered for giftedness. Determining the diversity of intelligence among those with ASD has implications for research, clinical practice, and neurological understanding.

The comparability of intelligence test results: Group- and individual-level comparisons of seven intelligence tests

A significant body of research has demonstrated that IQs obtained from different intelligence tests substantially correlate at the group level. Yet, there is minimal research investigating whether different intelligence tests yield comparable results for individuals. Examining this issue is paramount given that high-stakes decisions are based on individual test results. Consequently, we investigated whether seven current and widely used intelligence tests yielded comparable results for individuals between the ages of 4-20 years. Results mostly indicated substantial correlations between tests, although several significant mean differences at the group level were identified. Results associated with individual-level comparability indicated that the interpretation of exact IQ scores cannot be empirically supported, as the 95% confidence intervals could not be reliably replicated with different intelligence tests. Similar patterns also appeared for the individual-level comparability of nonverbal and verbal intelligence factor scores. Furthermore, the nominal level of intelligence systematically predicted IQ differences between tests, with above- and below-average IQ scores associated with larger differences as compared to average IQ scores. Analyses based on continuous data confirmed that differences appeared to increase toward the above-average IQ score range. These findings are critical as these are the ranges in which diagnostic questions most often arise in practice. Implications for test interpretation and test construction are discussed.

Intellectual Profile of Children with Autism Spectrum Disorder: Identification of verbal and nonverbal subscales predicting intelligence quotient

Objectives

This study aimed to explore the intelligence quotient (IQ) profile among children with autism spectrum disorder (ASD) and identify the most important subscales that predict the IQ. The analysis of an intellectual profile with age and gender differentials and the identification of a battery of subscales of intelligence are important for clinical management of ASD among children and for facilitating placement for remedial and educational services.

Methods

Data were collected through an exploratory study of 100 children aged between three and 13 years, who were referred to the department of child health and development in Sultan Qaboos University Hospital, a tertiary hospital, in Oman between June 2016 and June 2019.

Results

Among the 100 participants of this study, 79% were male, resulting in a male–female ratio of 4:1. The mean of full-scale IQ was found to be 68.6 ± 18.1. Furthermore, the mean of nonverbal IQ (73.5 ± 17.5) was significantly higher than that of verbal IQ (65.5 ± 17.6). Finally, more than half (61%) of the children were observed to have had mild to moderate impairment in their IQ levels.

Conclusions

Age and gender showed no significant association with IQ level. The regression analysis identified nonverbal fluid reasoning, nonverbal visual-spatial processing, nonverbal working memory and verbal knowledge as the significant predictors of total IQ. The crucial dimensions of verbal and nonverbal IQ identified in this study can be used to evaluate complicated cases.

IQ and Internalising Symptoms in Adolescents with ASD

Intelligence quotient (IQ), has been found to relate to the presence of internalising symptoms in autism spectrum disorder (ASD). This meta-analysis sought to clarify the direction of the relationship between IQ and two prevalent internalising symptoms, anxiety and depression, in adolescents with ASD. Secondly, this study aimed to highlight methodological factors contributing to inconsistent findings in existing research. Self-reported anxiety was found to be significantly higher in youth with a lower IQ, while depression was positively associated with IQ. Consequently, parents, schools and clinicians should be cautious of underestimating anxiety in youth with a lower IQ. However, care should also be taken to ensure adolescents with ASD without intellectual disabilities are not overlooked with regards to social and emotional support.

Parent-Reported Rates and Clinical Correlates of Suicidality in Children with Autism Spectrum Disorder: A Longitudinal Study

This study investigated rates of suicidal ideation (SI) and suicidal and/or self-injurious behaviour (SSIB) reported by parents on the Child Behavior Checklist for 178 children with ASD over four annual assessments (ages 7-11 years). Analyses examined the frequency and persistence of SI and SSIB, and the association of SI and SSIB at any time point with child characteristics and internalizing and externalizing problems at age 7. SI occurred in 9.6% of children and was associated with fewer ASD symptoms and better adaptive functioning at age 7. SSIB occurred in 14.6% and was associated with poorer adaptive functioning and more externalizing behaviour at age 7. Internalizing problems were not associated with SI or SSIB at any time point. SI and SSIB rarely co-occurred (4%).

mTOR and autophagy pathways are dysregulated in murine and human models of Schaaf-Yang syndrome

MAGEL2 is a maternally imprinted, paternally expressed gene, located in the Prader-Willi region of human chromosome 15. Pathogenic variants in the paternal copy of MAGEL2 cause Schaaf-Yang syndrome (SHFYNG), a neurodevelopmental disorder related to Prader-Willi syndrome (PWS). Patients with SHFYNG, like PWS, manifest neonatal hypotonia, feeding difficulties, hypogonadism, intellectual disability and sleep apnea. However, individuals with SHFYNG have joint contractures, greater cognitive impairment, and higher prevalence of autism than seen in PWS. Additionally, SHFYNG is associated with a lower prevalence of hyperphagia and obesity than PWS. Previous studies have shown that truncating variants in MAGEL2 lead to SHFYNG. However, the molecular pathways involved in manifestation of the SHFYNG disease phenotype are still unknown. Here we show that a Magel2 null mouse model and fibroblast cell lines from individuals with SHFYNG exhibit increased expression of mammalian target of rapamycin (mTOR) and decreased autophagy. Additionally, we show that SHFYNG induced pluripotent stem cell (iPSC)-derived neurons exhibit impaired dendrite formation. Alterations in SHFYNG patient fibroblast lines and iPSC-derived neurons are rescued by treatment with the mTOR inhibitor rapamycin. Collectively, our findings identify mTOR as a potential target for the development of pharmacological treatments for SHFYNG.

Psychometric Properties of the Merrill–Palmer–Revised Scales of Development in Preschool Children With Autism Spectrum Disorder

Psychometrically sound tests of intellectual ability are indispensable for research and assessment of children with autism spectrum disorder (ASD), yet few tests have been validated for use with this population. The Merrill–Palmer–Revised Scales of Development (M-P-R) is a standardized test of intellectual ability that was validated for use with typically developing preschoolers. The current study’s aim was to investigate the criterion validity of the M-P-R for assessing cognitive skills in preschoolers with ASD ( N = 180). Good concurrent validity was demonstrated, with a large positive correlation between the M-P-R Receptive Language domain and the PLS-4 Auditory Comprehension subscale. The Cognitive domain of the M-P-R showed a medium positive correlation with later WISC-4 scores, showing acceptable predictive validity. Cognitive strengths and weaknesses assessed using the M-P-R mirrored those described for other measures, with most children obtaining higher standard scores on the Cognitive than the Receptive Language domain. An exploratory factor analysis suggested that one factor accounted for the majority of variability in M-P-R domains.

Does IQ = IQ? Comparability of Intelligence Test Scores in Typically Developing Children

Numerous intelligence tests are available to psychological diagnosticians to assess children's intelligence, but whether they yield comparable test results has been little studied. We examined test scores of 206 typically developing children aged 6 to 11 years on five German intelligence tests (Reynolds Intellectual Assessment Scales; Snijders Oomen Nonverbal Intelligence Test; Intelligence and Development Scales; Wechsler Intelligence Scale for Children, 4th edition; Culture Fair Intelligence Test Scale 2), which were individually administered. On a sample level, the test scores showed strong correlation and little or no mean difference. These results indicate that the tests measure a similar underlying construct, which is interpreted as general intelligence. On an individual level, however, test scores significantly differed across tests for 12% to 38% of the children. Differences did not depend on which test was used but rather on unexplained error. Implications for the application of intelligence assessment in psychological practice are discussed.

Autism spectrum disorders and neuropathology of the cerebellum

The cerebellum contains the largest number of neurons and synapses of any structure in the central nervous system. The concept that the cerebellum is solely involved in fine motor function has become outdated; substantial evidence has accumulated linking the cerebellum with higher cognitive functions including language. Cerebellar deficits have been implicated in autism for more than two decades. The computational power of the cerebellum is essential for many, if not most of the processes that are perturbed in autism including language and communication, social interactions, stereotyped behavior, motor activity and motor coordination, and higher cognitive functions. The link between autism and cerebellar dysfunction should not be surprising to those who study its cellular, physiological, and functional properties. Postmortem studies have revealed neuropathological abnormalities in cerebellar cellular architecture while studies on mouse lines with cell loss or mutations in single genes restricted to cerebellar Purkinje cells have also strongly implicated this brain structure in contributing to the autistic phenotype. This connection has been further substantiated by studies investigating brain damage in humans restricted to the cerebellum. In this review, we summarize advances in research on idiopathic autism and three genetic forms of autism that highlight the key roles that the cerebellum plays in this spectrum of neurodevelopmental disorders.

Concurrent validity of the differential ability scales, second edition with the Mullen Scales of Early Learning in young children with and without neurodevelopmental disorders

Estimates of intelligence in young children with neurodevelopmental disorders are critical for making diagnoses, in characterizing symptoms of disorders, and in predicting future outcomes. The limitations of standardized testing for children with developmental delay or cognitive impairment are well known: Tests do not exist that provide developmentally appropriate material along with norms that extend to the lower reaches of ability. Two commonly used and interchanged instruments are the Mullen Scales of Early Learning (MSEL), a test of developmental level, and the Differential Ability Scales, second edition (DAS-II), a more traditional cognitive test. We evaluated the correspondence of contemporaneous MSEL and the DAS-II scores in a mixed sample of children aged 2-10 years with autism spectrum disorder (ASD), non-ASD developmental delays, and typically developing children across the full spectrum of cognitive ability. Consistent with published data on the original DAS and the MSEL, scores on the DAS-II and MSEL were highly correlated. However, curve estimation revealed large mean differences that varied as a function of the child's cognitive ability level. We conclude that interchanging MSEL and DAS-II scores without regard to the discrepancy in scores may produce misleading results in both cross-sectional and longitudinal studies of children with and without ASD, and, thus, this practice should be implemented with caution.