Investigating the structure and invariance of the Wechsler Adult Intelligence Scales, Fourth Edition in a sample of adults with intellectual disabilities

Adapting a Self-Concept Questionnaire for Students With Intellectual Disabilities: An Inclusive Research Approach

BACKGROUND

Given the significant gap in tailored assessment tools, this research seeks to adapt the Self-concept (Form 5-AF5) questionnaire for young students with intellectual disabilities, employing an inclusive approach.

METHOD

Twenty-three disability experts initially assessed questionnaire suitability, leading to revisions for clarity. Cognitive interviews with eight students with intellectual disabilities clarified questions, and both original and adapted questionnaires were administered to students with and without intellectual disabilities for equivalence verification.

RESULTS

The adapted scale showed good internal consistency. The correlation between scores of students without intellectual disabilities on original and adapted questionnaires exceeded 0.70. Students with intellectual disabilities reported higher levels of academic self-concept than their peers without intellectual disabilities.

CONCLUSIONS

The adaptation of the Self-concept (Form 5-AF5) questionnaire in this research facilitates the comparison of diverse student populations, as demonstrated by the alignment of results between the original and adapted questionnaires in the general student population.

Measuring intelligence in Autism and ADHD: Measurement invariance of the-Binet 5th edition and impact of subtest scatter on abbreviated IQ accuracy

Scatter and heterogeneity in cognitive profiles is thought to be common in autism spectrum disorder (ASD), which may indicate differences in the construct of IQ. However, less research has investigated IQ scatter in attention-deficit/hyperactivity disorder (ADHD). Scatter is also thought to negatively impact the predictive validity of IQ summary scores, although there is research refuting this notion. Abbreviated IQ tests, such as the Stanford-Binet fifth edition (SB-5) abbreviated battery IQ (ABIQ), may be especially susceptible to the influence of scatter. We tested the measurement invariance of the SB-5 as well as the predictive validity of the ABIQ in predicting FSIQ in 1679 youth (21% female) ages 2-16 years with a clinical diagnosis of ASD or ADHD. Results indicated the SB-5 is measuring IQ the same way in ASD and ADHD. There were no differences between diagnostic groups in scatter between ABIQ (i.e., routing) subtests. Additionally, scatter was not related to dimensional autistic traits. Higher degree of scatter was associated with poorer predictive validity of the ABIQ and a higher likelihood of overestimating FSIQ, regardless of diagnosis. Overall, we found more similarities than differences between the ASD and ADHD groups. Our results show that the SB-5 ABIQ is generally a strong predictor of FSIQ in youth with neurodevelopmental disorders. However, the use of the SB-5 ABIQ in research and clinical applications, without consideration of scatter on routing subtests, is potentially problematic.

Cognitive Profile Discrepancies among Typical University Students and Those with Dyslexia and Mixed-Type Learning Disorder

BACKGROUND

Previous studies have identified areas of cognitive weakness in children diagnosed with Specific Learning Disorder (SLD), in the areas of working memory and processing speed in particular. In adulthood, this literature is still scant, and no studies have compared the cognitive profile of university students with dyslexia (DD) with that of students with Mixed-type SLD.

METHOD

Thus, in this study, the WAIS-IV was used to examine the cognitive functioning of three groups of university students: students with DD, with Mixed-type SLD, and typical students. Statistical analyses were performed to examine differences in WAIS-IV FSIQ, main, and additional indexes and subtests.

RESULTS

The results showed strengths in perceptual reasoning and good verbal comprehension abilities in both the DD and Mixed-type SLD group, with weaknesses in working memory and processing speed, leading to a pattern of a better General Ability Index (GAI) than Cognitive Proficiency Index (CPI) in both clinical groups. Thus, discrepancies between GAI and CPI, well documented in children with SLD, still manifest in adulthood in university students. Our findings also revealed worse cognitive performance in university students with mixed learning disorder relative to students with only a reading deficit.

CONCLUSIONS

The cognitive features and distinctive subtest profiles that emerged should guide the assessment and the definitions of intervention programs, special educational needs, and strategies of compensation.

Using the learning disability screening questionnaire to help identify people with an intellectual disability in homeless services

BACKGROUND

We explored the accuracy of using the learning disability screening questionnaire (LDSQ) in services for people experiencing homelessness in the United Kingdom.

METHOD

We examined the concordance between the LDSQ outcomes and assessments of intellectual disability. Seventy adults experiencing homelessness completed the LDSQ. Staff completed the LDSQ and a measure of adaptive functioning for 38 of this group. Nine participants received an intellectual assessment.

RESULTS

Sensitivity and specificity for the LDSQ when completed by staff was 83% and 96% respectively and 50% and 92% when completed by the individual. Seven people had intellectual and adaptive functioning in the intellectual disability range.

CONCLUSION

The results suggest that the LDSQ would be an appropriate and beneficial screening tool to use within services for people experiencing homelessness. More accurate results would be likely if it were completed by staff.

Investigating the Relation of Intelligence and Executive Functions in Children and Adolescents with and without Intellectual Disabilities

Despite their separate research traditions, intelligence and executive functioning (EF) are both theoretically and empirically closely related to each other. Based on a subsample of 8- to 20-year-olds of the standardization and validation sample (N = 1540) of an internationally available instrument assessing both cognitive abilities, this study aimed at investigating a comprehensive structural model of intelligence and EF tasks and at gaining insight into whether this comprehensive model is applicable across sexes and age groups as well as to a subsample of participants with (borderline) intellectual disabilities (IQ ≤ 85, n = 255). The results of our exploratory factor analysis indicated one common EF factor that could be sufficiently integrated into the intelligence model within our confirmatory factor analyses. The results suggest that the EF factor can be added into the model as a sixth broad ability. The comprehensive model largely showed measurement invariance across sexes and age groups but did not converge within the subsample of participants with (borderline) intellectual disabilities. The results and implications are discussed in light of the current literature.

How do we measure attention? Using factor analysis to establish construct validity of neuropsychological tests

We investigated whether standardized neuropsychological tests and experimental cognitive paradigms measure the same cognitive faculties. Specifically, do neuropsychological tests commonly used to assess attention measure the same construct as attention paradigms used in cognitive psychology and neuroscience? We built on the “general attention factor”, comprising several widely used experimental paradigms (Huang et al., 2012). Participants (n = 636) completed an on-line battery (TestMyBrain.org) of six experimental tests [Multiple Object Tracking, Flanker Interference, Visual Working Memory, Approximate Number Sense, Spatial Configuration Visual Search, and Gradual Onset Continuous Performance Task (Grad CPT)] and eight neuropsychological tests [Trail Making Test versions A & B (TMT-A, TMT-B), Digit Symbol Coding, Forward and Backward Digit Span, Letter Cancellation, Spatial Span, and Arithmetic]. Exploratory factor analysis in a subset of 357 participants identified a five-factor structure: (1) attentional capacity (Multiple Object Tracking, Visual Working Memory, Digit Symbol Coding, Spatial Span), (2) search (Visual Search, TMT-A, TMT-B, Letter Cancellation); (3) Digit Span; (4) Arithmetic; and (5) Sustained Attention (GradCPT). Confirmatory analysis in 279 held-out participants showed that this model fit better than competing models. A hierarchical model where a general cognitive factor was imposed above the five specific factors fit as well as the model without the general factor. We conclude that Digit Span and Arithmetic tests should not be classified as attention tests. Digit Symbol Coding and Spatial Span tap attentional capacity, while TMT-A, TMT-B, and Letter Cancellation tap search (or attention-shifting) ability. These five tests can be classified as attention tests.

Assessing Cognitive Abilities Using the WAIS-IV: An Item Response Theory Approach

Background: The Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) has been adapted to 28 different cultures and there has been considerable interest in examining its structure through exploratory and confirmatory factor analysis. This study investigates item and scale properties of the Egyptian WAIS-IV using item response theory (IRT) models. Methods: The sample consisted of 250 adults from Egypt. The item-level and subtest statistical properties of the Egyptian WAIS-IV were established using a combination of four dichotomous IRT models and four polytomous IRT models. In addition, factor analysis was performed to investigate the dimensionality of each subtest. Results: Factor analysis indicated the unidimensionality of each subtest. Among IRT models, the two-parameter logistic model provided a good fit for dichotomous subtests, while the graded response model fitted the polytomous data. Most items of the Egyptian WAIS-IV showed high discrimination, and the scale was adequately informative across the levels of latent traits (i.e., cognitive variables). However, each subtest included at least some items with limited ability to distinguish between individuals with differing levels of the cognitive variable being measured. Furthermore, most subtests have items that do not follow the difficulty rank they are ascribed in the WAIS-IV manual. Conclusions: Overall, the results suggest that the Egyptian WAIS-IV offers a highly valid assessment of intellectual abilities, despite the need for some improvements.

Verbal Short-Form FSIQ Estimations for Possible Use With Individuals With Motor and Visual Impairment or in Virtual Environments

OBJECTIVE

Abbreviated and virtual neuropsychological assessment practices are growing in popularity and viable alternatives to traditional testing methods are needed, especially in the face of global health concerns. This study generated and examined short form (SF) full-scale IQ (FSIQ) estimations, which lend themselves to virtual test administration.

METHODS

Archival data were procured from 318 concurrent cognitive evaluations at a university clinic. Twenty-six unique SF combinations, including dyads, triads, tetrads, and pentads, were created from Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV) subtests within verbal comprehension and working memory indices due to these tests' ability to be administered without visual stimuli or psychomotor involvement.

RESULTS

Stepwise regression analyses revealed 9 SF combinations (i.e., 1 pentad, 3 tetrads, 2 triads, and 3 dyads) that significantly accounted for unique variance in FSIQ scores and provided good accuracy estimating FSIQ.

CONCLUSION

Results suggest the potential viability of verbal WAIS-IV SF FSIQ estimations for clinical use when assessing patients with motor or visual impairments, as well as performing tele-neuropsychological services.

Frequency of occurrence of four- and five-factor WAIS-IV profiles

Interpretive strategies for the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) include Wechsler's four-factor structure and the five-factor Cattell-Horn-Carroll (CHC) model. The frequency of profile occurrence and the contribution of demographic- and ability-related variables to their incidence are unknown. Current participants were 291 referrals (males = 134; female = 157) for neuropsychological evaluation with mean years for age and education of 34.94 (SD = 13.53) and 12.74 (SD = 2.46), respectively. Lichtenberger and Kaufman's guidelines for selecting each model were applied. Of the total, 67.3% were four-factor and 32.6% were five-factor profiles. The same pattern emerged when participants were subdivided by gender, education, ethnicity, IQ, and diagnosis. A noteworthy association between IQ and profile type emerged. When IQ increased, four-factor profiles declined and five-factors increased. A logistic regression, using demographics, IQ, and diagnosis as predictors, correctly classified 64.8% of participants. The average subtest intercorrelations and g saturations in the four-factor group were substantially larger than those for five-factor participants. These findings were consistent with Spearman's differentiation by ability hypothesis.

Understanding the Profile of Cancer-Related Cognitive Impairments: A Critique of Meta-Analyses

A large body of evidence indicates that cancer survivors who have undergone chemotherapy have cognitive impairments. Substantial disagreement exists regarding which cognitive domains are impaired in this population. We suggest that is in part due to inconsistency in how neuropsychological tests are assigned to cognitive domains. The purpose of this paper is to critically analyze the meta-analytic literature on cancer-related cognitive impairments (CRCI) to quantify this inconsistency. We identified all neuropsychological tests reported in seven meta-analyses of the CRCI literature. Although effect sizes were generally negative (indicating impairment), every domain was declared to be impaired in at least one meta-analysis and unimpaired in at least one other meta-analysis. We plotted summary effect sizes from all the meta-analyses and quantified disagreement by computing the observed and ideal distributions of the one-way χ2 statistic. The actual χ2 distributions were noticeably more peaked and shifted to the left than the ideal distributions, indicating substantial disagreement among the meta-analyses in how neuropsychological tests were categorized to domains. A better understanding of the profile of impairments in CRCI is essential for developing effective remediation methods. To accomplish this goal, the research field needs to promote better agreement on how to measure specific cognitive functions.

Examination of Wechsler adult Intelligence Scale-Fourth Edition short-form IQ estimations in an outpatient psychoeducational sample

OBJECTIVE

The Wechsler Adult Intelligence Scale, 4th edition (WAIS-IV) is a commonly utilized cognitive battery across many clinical settings. However, due to various patient variables, an abbreviated assessment of intellectual abilities, may be clinically advantageous to allow for a more thorough assessment of other cognitive domains. The current study represents an attempt to propose additional short-form IQ estimations in an outpatient clinical sample.

METHODS

We examined archival data from 318 concurrent psychological/psychoeducational evaluations performed within a university clinic (M_age = 28.67; 53.8% women). Thirty-six unique 4-subtest short-form IQ combinations were created to ensure that each WAIS-IV index score was represented by a single subtest.

RESULTS

Complete data for the ten core subtests and FSIQ were available for 192 cases. Stepwise regression analyses revealed three short-form combinations that significantly accounted for unique variance in true FSIQ scores in the final model (R² = .981, F[3, 188] = 3257.597, p < .001). Regression-based and prorated FSIQ estimates were calculated, and both methods revealed that approximately 70-75% of participants' FSIQ estimates fell within five Standard Score points of true FSIQ.

CONCLUSION

Results suggest the utility of three derived 4-subtest short-form IQ estimations for use within a clinical sample.

The Longitudinal Measurement of Reasoning Abilities in Students With Special Educational Needs

Students with special educational needs in the area of learning (SEN-L) have learning disabilities that can lead to academic difficulties in regular schools. In Germany, these students are frequently enrolled in special schools providing specific training and support for these students. Because of their cognitive difficulties, it is unclear whether standard achievement tests that are typically administered in educational large-scale assessments (LSA) are suitable of students with SEN-L. The present study evaluated the psychometric properties of a short instrument for the assessment of reasoning abilities that was administered as part of a longitudinal LSA to German students from special schools (N = 324) and basic secondary schools (N = 338) twice within 6 years. Item response modeling demonstrated an essentially unidimensional scale for both school types. Few items exhibited systematic differential item functioning (DIF) between students with and without SEN-L, allowing for valid cross-group comparisons. However, change analyses across the two time points needed to account for longitudinal DIF among students with SEN-L. Overall, the cognitive test allowed for a valid measurement of reasoning abilities in students with SEN-L and comparative analyses regarding students without SEN-L. These results demonstrate the feasibility of incorporating students with SEN-L into educational LSAs.

Hierarchical Structure of the Wechsler Adult Intelligence Scale–Fourth Edition with an Egyptian Sample

The Wechsler Adult Intelligence Scale–Fourth Edition (WAIS-IV) is one of the most well-known tests in the field of adult intelligence assessment. This study explores the validity of the Egyptian adaptation for the subscales of the WAIS-IV. Confirmatory factor analysis (CFA) indicated that the first-order, second-order, and bifactor models of both the five-factor Cattel–Horn–Carroll (CHC) and the four-factor structures fitted with the WAIS-IV. When the Arithmetic subscale was pathed to Perceptual Reasoning and Working Memory, the modified four first-order factor showed a better fit than any other model. Estimates of internal consistency revealed that Cronbach’s alpha was very high (.91) for the WAIS-IV scale and for four-factor structures (ranging from .81 to .95), while [Formula: see text] was low (0.61) for the WAIS-IV scale and for four-factor structures, ranging from 0.20 to 0.68. Overall, these findings provided adding evidence about the dimensionality of WAIS-IV with a new sample.

The importance of measurement invariance in neurocognitive ability testing

OBJECTIVE

Neurocognitive test batteries such as recent editions of the Wechsler's Adult Intelligence Scale (WAIS-III/WAIS-IV) typically use nation-level population-based norms. The question is whether these batteries function in the same manner across different subgroups based on gender, age, educational background, socioeconomic status, ethnicity, mother tongue, or race. Here, the author argues that measurement invariance is a core issue in determining whether population-based norms are valid for different subgroups.

METHOD

The author introduces measurement invariance, argues why it is an important topic of study, discusses why invariance might fail in cognitive ability testing, and reviews a dozen studies of invariance of commonly used neurocognitive test batteries.

RESULTS

In over half of the reviewed studies, IQ batteries were not found to be measurement invariant across groups based on ethnicity, gender, educational background, cohort, or age. Apart from age and cohort, test manuals do not take such lack of invariance into account in computing full-scale IQ scores or normed domain scores.

CONCLUSIONS

Measurement invariance is crucial for valid use of neurocognitive tests in clinical, educational, and professional practice. The appropriateness of population-based norms to particular subgroups should depend also on whether measurement invariance holds with respect to important subgroups.

An examination of the Wechsler Adult Intelligence Scales, Fourth Edition (WAIS-IV) in individuals with complicated mild, moderate and Severe traumatic brain injury (TBI)

This study examined the clinical utility of the Wechsler Adult Intelligence Scales-Fourth Edition (WAIS-IV) in individuals with complicated mild, moderate or severe TBI. One hundred individuals with TBI (n = 35 complicated mild or moderate TBI; n = 65 severe TBI) and 100 control participants matched on key demographic variables from the WAIS-IV normative dataset completed the WAIS-IV. Univariate analyses indicated that participants with severe TBI had poorer performance than matched controls on all index scores and subtests (except Matrix Reasoning). Individuals with complicated mild/moderate TBI performed more poorly than controls on the Working Memory Index (WMI), Processing Speed Index (PSI), and Full Scale IQ (FSIQ), and on four subtests: the two processing speed subtests (SS, CD), two working memory subtests (AR, LN), and a perceptual reasoning subtest (BD). Participants with severe TBI had significantly lower scores than the complicated mild/moderate TBI on PSI, and on three subtests: the two processing speed subtests (SS and CD), and the new visual puzzles test. Effect sizes for index and subtest scores were generally small-to-moderate for the group with complicated mild/moderate and moderate-to-large for the group with severe TBI. PSI also showed good sensitivity and specificity for classifying individuals with severe TBI versus controls. Findings provide support for the clinical utility of the WAIS-IV in individuals with complicated mild, moderate, and severe TBI.