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.

Common Factor Structure of the Ten Subtest Wechsler Adult Intelligence Scale-Fourth Edition in a Clinical Sample and 15 Subtest Version in the Standardization Sample.

OBJECTIVE: The 10 core subtests of the Wechsler Adult Intelligence Scale-IV (WAIS-IV) suffice to produce the 4 index scores for clinical assessments. Factor analytic studies with the full complement of 15 subtests reveal a 5-factor structure that aligns with Cattell-Horn-Carroll taxonomy of cognitive abilities. The current study investigates the validity of 5-factor structure in a clinical setting with reduced number of 10 subtests. METHOD: Confirmatory factor analytic models were fitted to a clinical neurosciences archival data set (n_Male = 166, n_Female = 155) and to 9 age-group samples of the WAIS-IV standardization data (n = 200 for each group). The clinical and the standardization samples differed as (a) the former comprised scores from patients, aged 16 to 91, with disparate neurological diagnosis whereas the latter was demographically stratified, (b) only the 10 core subtests in the former but all 15 subtests in the latter were administered, and (c) the former had missing data, but the latter was complete. RESULT: Despite empirical constraints to eliciting 5 factors with only 10 indicators, the well-fitting, 5-factor (acquired knowledge, fluid intelligence, short-term memory, visual processing, and processing speed) measurement model evinced metric invariance between the clinical and standardization samples. CONCLUSION: The same cognitive constructs are measured on the same metrics in every sample examined and provide no reason to reject the assumption that the 5 underlying latent abilities of the 15 subtest version in the standardization samples can also be inferred from the 10 subtest version in clinical populations.

A Direct Comparison of 10 WAIS-IV Digit Span Embedded Validity Indicators among a Mixed Neuropsychiatric Sample with Varying Degrees of Cognitive Impairment.

OBJECTIVE: Reliable Digit Span (RDS), RDS-Revised (RDS-R), and age-corrected scaled score (ACSS) have been previously validated as embedded performance validity tests (PVTs) from the Wechsler Adult Intelligence Scale-IV Digit Span subtest (WAIS-IV DS). However, few studies have directly compared the relative utility of these and other proposed WAIS-IV DS validity indicators within a single sample. METHOD: This study compared classification accuracies of 10 WAIS-IV DS indices in a mixed neuropsychiatric sample of 227 outpatients who completed a standardized neuropsychological battery. Participants with ≤1 PVT failures of the four, freestanding criterion PVTs constituted the valid group (n = 181), whereas those with ≥2 PVT failures formed the invalid group (n = 46). Among the valid group, 113 met criteria for mild cognitive impairment (MCI). RESULTS: Classification accuracies for all DS indicators were statistically significant across the overall sample and subsamples with and without MCI, apart from indices derived from the Forward trial in the MCI sample. DS Sequencing ACSS, working memory RDS (wmRDS), and DS ACSS emerged as the most effective predictors of validity status, with acceptable to excellent classification accuracy for the overall sample (AUCs = 0.792-0.816; 35%-50% sensitivity/88%-96% specificity). CONCLUSIONS: Although most DS indices demonstrated clinical utility as embedded PVTs, DS Sequencing ACSS, wmRDS, and DS ACSS may be particularly robust to cognitive impairment, minimizing risk of false positive errors while identifying noncredible performance. Moreover, DS indices incorporating data from multiple trials (i.e., wmRDS, DS ACSS) also generally yielded greater classification accuracy than those derived from a single trial.

Cognitive profiles in bipolar I disorder and associated risk factors: Using Wechsler adult intelligence scale-IV.

Background: Despite the growing evidence of cognitive impairments in bipolar disorder (BD), little work has evaluated cognitive performances utilizing the latest version of the Wechsler Intelligence Scale-IV (WAIS-IV), which is one of the most widely used neurocognitive assessments in clinical settings. Furthermore, clinical characteristics or demographic features that negatively affect the cognitive functioning of BD were not systematically compared or evaluated. Accordingly, the present study aimed to examine the cognitive profile of bipolar I disorder (BD-I) patients and associated risk factors. Methods: Participants included 45 patients, diagnosed with BD-I, current or most recent episode manic, and matching 46 healthy controls (HC). Cognitive performance was evaluated via WAIS-IV, and clinical characteristics of the BD-I group were examined via multiple self- and clinician-report questionnaires. Results: Multivariate analysis of covariance (MANCOVA) results indicated that the BD-I group demonstrated significantly poorer performance compared to the HC group in subtests and indexes that reflect working memory and processing speed abilities. Redundancy analysis revealed that overall symptom severity, manic symptom severity, and anxiety were significant predictors of cognitive performance in BD-I, while age of onset, past mood disorder history, depression severity, and impulsiveness showed comparatively smaller predictive values. Conclusion: The current study suggests cognitive deterioration in the cognitive proficiency area while generalized ability, including verbal comprehension and most of the perceptual reasoning skills, remain intact in BD-I. The identified risk factors of cognitive performance provide specific clinical recommendations for intervention and clinical decision-making.

Wechsler Intelligence Scale for Adults - Fourth Edition profiles of adults with autism spectrum disorder.

AIM: In this study, we have compared 229 Wechsler Adults Intelligence Scale - Fourth Edition (WAIS-IV) cognitive profiles of different severity adults with autism spectrum disorder to verify the impact of several variables including sex, age, level of education and autism severity level in an Italian sample. Moreover, we wanted to find out the optimal cut points for the major intelligence quotients in order to discriminate autism severity levels. METHODS: Participants were recruited from two National Health System Center in two different Italian regions and were assessed with gold-standard instruments as a part of their clinical evaluation. According to DSM-5, cognitive domains were also measured with multi-componential tests. We used the Italian adaptation of WAIS-IV. We checked our hypotheses using linear regression models and receiver operating characteristics (ROC) curves. RESULTS: Our results showed that age and level of education have a strong impact on Verbal Comprehension (VCI) and Working Memory Indexes (WMI). Gender differences are relevant when considering the VCI and Processing Speed index (PSI) in which women obtained the best performance. These differences are still relevant when considering cut points of ROC because 69 resulted to be the optimal cut point for women, 65 for men. CONCLUSIONS: Few conclusions can be assumed only examining Full Scale Intelligence Quotient (FSIQ) scores as it includes many different information about broader cognitive abilities. Looking deeper at main indexes and their subtests findings are consistent with previous research on the disorder (moderate correlations of FSIQ, Perceptual Reasoning index, WMI and PSI with the participants' age), while other results are unforeseen (no effect of sex found on FSIQ score) or novel (significant effect of education on VCI and WMI). Using an algorithm predicting optimal cut point for discriminating through autism severity levels can help clinicians to better label and quantify the required help a person may need, a test cannot replace diagnostic and clinical evaluation by experienced clinicians.

A validated WAIS-IV short-form to estimate intellectual functioning in myotonic dystrophy type 1.

Currently, no rapid and specific instrument is available to briefly estimate intelligence in patients with myotonic dystrophy type 1 (DM1), a multisystemic disease that involves the CNS and is associated with cognitive deficits and low intellectual functioning. This study aimed to develop a DM1-specific and valid short-form of the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) to estimate intellectual functioning in this population. Thirty non-congenital DM1 patients (10 female; mean age=46.77; SD= 9.76) were assessed with the WAIS-IV. Data were analyzed following two independent strategies: A) multiple linear regression with the aim of maintaining the scale's factorial structure; and B) correlational analyses between scores on all WAIS-IV subtests and Full-Scale IQ (FSIQ). Validity of the resulting short-forms was also analyzed. Three short-forms were developed: Proposal A from strategy A (Vocabulary, Block Design, Arithmetic and Symbol Search), Proposal B1 (Vocabulary, Block Design, Digit Span and Visual Puzzles) and Proposal B2 (Vocabulary and Block Design), from strategy B. All three short-forms showed a strong and significant correlation with the FSIQ and were considered psychometrically acceptable. Arguments in favor of Proposal B1 are discussed. Assessing FSIQ with these short-forms will be useful for avoiding long assessment procedures in a population characterized by high fatigability.

Differences in executive functioning between adults with ADHD and those diagnosed with other psychiatric diagnoses: Utility of the CTMT and the WAIS-IV.

In this study, the utility of the Comprehensive Trail Making Test (CTMT) and WAIS-IV working memory (WMI) and processing speed (PSI) indices in assessment of ADHD were examined. Using retrospective analysis of data from two private practices, patients were classified as having ADHD, having another psychiatric disorder, or having comorbid ADHD and other psychiatric disorder. Results indicated that significant differences existed in performance across the three groups [F(6, 246) = 3.38, p = .003; Pillai's Trace = 0.152, partial η2 = 0.076] on CTMT scores (p < .05), WMI scores (p ≤ .001) and PSI scores (p < .05). Logistic regression analyses indicated WMI and CTMT trail 5 scores were individually useful indicators in identifying the presence of ADHD. Analysis also indicated minimal increase in correct classification of presence or absence of ADHD through combining CTMT, WMI, and PSI scores. Clinical implications for neuropsychological assessment and differential diagnosis of ADHD are discussed.

Cognitive Profiles of Adolescent Inpatients with Substance Use Disorder.

The prevalence of substance abuse is high during adolescence, and several studies have linked the use of alcohol and cannabis in adolescence to different cognitive impairments. To investigate whether specific cognitive deficits can be observed in adolescents with substance use disorder (SUD), we compared the cognitive profiles of inpatient adolescents diagnosed with SUD to a control group matched for sex, age and educational status. The inpatient adolescents received diagnoses of cannabis use disorder, alcohol use disorder or both. We compared the WISC-V profiles of 22 inpatients (45.5% female, Mage: 14.5; SD: 0.8) and the WAIS-IV profiles of 27 inpatients (44.4% female, Mage: 17.1; SD: 0.9) to 49 matched control participants with no diagnosed SUD. At the time of testing, participants were hospitalized for treatment of their SUD and were abstinent for a period of at least 6 weeks. To gain greater power, we jointly analyzed the Verbal Comprehension Index, Working Memory Index, Processing Speed Index and Full Scale IQ as assessed by WISC-V and WAIS-IV. The clinical group performed significantly worse than the control group on all the above indices. When only the group of inpatients was observed, in a model with the factors sex, educational status, presence of a comorbid diagnosis of depression and the number of comorbid diagnoses, only the factor educational status was significantly associated with the Full Scale IQ, whereas the factors sex and a comorbid diagnosis of depression in this group were associated with the Processing Speed Index. The results show that adolescents diagnosed with SUD (cannabis and/or alcohol) display broad cognitive impairments after 6 weeks of abstinence. Future research is required to further explore the role of comorbid diagnoses.

Long-term low dose nitisinone therapy in adults with alkaptonuria shows no cognitive decline or increased severity of depression.

Little is documented on whether nitisinone-induced hypertyrosinaemia alters cognitive functioning or leads to worsening depression in alkaptonuria (AKU). Wechsler Adult Intelligence Scale-IV (WAIS-IV) and Beck Depression Inventory-II (BDI-II) assessments were performed before and annually following treatment with nitisinone 2 mg daily to assess the impact on cognitive functioning and severity of depression. Serum tyrosine concentrations were also measured annually. WAIS-IV: 63 patients (27 females/36 males: mean age[years] [±standard deviation, range] 55.7[13.7, 26-79]; 60.3[9.6, 19-75]) were included at baseline for assessment of: verbal comprehension (VC), perceptual reasoning (PR), working memory (WM), and processing speed (PS) using separate indices. Over the 6-year period studied 43, 39, 36, 29, 26 and 15 patients had annual assessments. Using a longitudinal model (age and sex adjusted) no significant differences were observed in any of the indices over this period, apart from VC which showed a significant increase after adjustment for sex (p < 0.05). BDI-II: 74 patients (32 females/42 males: mean age[years] [±standard deviation, range] 56.1[13.2, 26-79]; 42 males, 51.5[16.3, 19-70]) were included at baseline. Over the 7-year period studied 48, 47, 38, 34, 32, 24 and 12 patients had annual assessments. No significant differences in BDI-II scores were observed when compared to baseline. Hypertyrosinaemia was observed in all patients following treatment with nitisinone (p < 0.001, at all annual visits). Serum tyrosine was not correlated with WAIS-IV sub-test indices or BDI-II scores pre- or post-nitisinone therapy. These findings suggest that treatment with nitisinone does not affect cognitive functioning and or lead to increased severity of depression.

Does high scatter on the Wechsler Adult Intelligence Scale-Fourth Edition general ability index reduce validity in predicting Wechsler Memory Scale-Fourth Edition indexes?

We examined whether significant scatter in WAIS-IV GAI will reduce its validity to predict performance on WMS-IV indexes. Participants were 330 individuals with neurological, psychiatric, or neurodevelopmental disorders and 59 referrals who were found to be free of a diagnosable disorder. For VCI > PRI, 59.32% were significant at p < .05 and 12.29% were >22 points. For VCI < PRI, 48.37% were significant at p < .05 and 7.19% were >22 points. Inter-subtest scatter across GAI subtests indicated 82.26% of individuals had a significant scatter range and 13.88% had an unusually large range (≥8). For the VCI, 49.10% had significant scatter (≥3) and 12.08% had an unusually large scatter range (≥5). On the PRI, 43.19% had a significant scatter range (≥4) and 12.85% had an unusually large degree of scatter (≥6). Moderation analyses revealed GAI was a significant predictor of each WMS-IV index. The interaction term of GAI with GAI scatter was not significant for any indexes, indicating that regression equations for predicting WMS-IV scores from GAI did not vary significantly across levels of scatter. Estimation of WMS-IV indexes from the GAI is justified even when significant VCI-PRI discrepancies are present and there is unusual variability across the GAI subtests.

The validity of abbreviated forms of the National Adult Reading Test and Spot-the-Word 2 for estimating full-scale IQ.

ABSTRACTIn this study, we validate an earlier proposal for an abridged 17-item National Adult Reading Test (NART) by comparing its performance in estimating full-scale IQ against both the full test and the Spot-the-Word 2 (STW-2) test in a new cohort. We also compare the performance of the 17-item NART to two previous attempts to shorten this test, the Mini-NART and the Short NART. Findings include that NART 17 is numerically stronger and statistically equivalent to the other short variants, the full 50-word NART, and STW-2. Unlike the Short NART, the 17-item NART is usable for participants of all ability levels rather than only those with low reading ability, while offering equally precise premorbid estimates. We also compute that two-thirds of STW-2 is ostensibly redundant for full-scale IQ estimation and we, therefore, propose that, subject to additional verification in an independent sample, an abridged version of this test may also benefit clinical practice.

Relative subtest scatter on the WAIS-IV in a clinical sample referred for outpatient neuropsychological evaluation.

OBJECTIVE: The primary aim of this study was to examine relative inter-subtest variability, or scatter, on the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) in a clinical sample of patients referred for neuropsychological evaluation and compare the findings to corresponding data from the scale's standardization sample. METHOD: Participants were 638 individuals diagnosed primarily with neurological, psychiatric, or neurodevelopmental disorders who completed the 10 core subtests of the WAIS-IV as part of a comprehensive assessment battery. RESULTS: Mean participant scores on the WAIS-IV Full Scale IQ and all index composites were within the average range, overall, but were significantly below those of the standardization sample. The correlation between scatter range and highest subtest scaled score was significant, r = .65, indicating a greater degree of subtest scaled score variability in participants with higher than average peak subtest scaled scores than participants with average or below peak subtest scaled scores. Mean variability by highest subtest scaled score was, in most cases, larger in this clinical sample relative to the scale's standardization sample. Exploratory secondary analyses also revealed specific differences in relative scatter based on diagnostic group classification. CONCLUSIONS: Subtest scatter on the WAIS-IV is common among both healthy individuals and clinical patients. Although somewhat higher in this investigation's clinical sample, the significance of this finding generally appears to be of nominal value during interpretation of individual cases but may have some utility in formulating hypotheses when considered in conjunction with reliability data and other approaches for analyzing test scores. High scatter is not pathognomonic of abnormality, and at least some degree of caution is warranted when interpreting subtest scaled score differences on the WAIS-IV.

Feasibility of administering the WAIS-IV using a home-based telehealth videoconferencing model.

Use of telehealth to deliver neuropsychological services has proven to be a feasible approach, however, there is limited research which has examined the reliability of home-based assessment models using a comprehensive intelligence test. The aim of this study was to examine the reliability and feasibility of a home-based videoconferencing administration of the Wechsler Adult Intelligence Scales-4th Edition (WAIS-IV).Thirty healthy participants (aged 18-40 years) completed the WAIS-IV both in-person and via home-based videoconferencing utilizing a randomized counter-balanced methodology to attempt to control for an order effect. Paper record forms for Coding/Symbol Search and Blocks were sent and returned via tamper proof courier packs. Participants completed an online survey of their experiences of TNP following completion of their assessments. Group mean comparisons, intra class correlation coefficients (ICCs) and Bland-Altman measures of bias were calculated.Findings from both modalities were highly concordant across all WAIS-IV subtests and indices, with all ICCs rated as "excellent," (≥0.9). There were no significant mean group differences and no evidence of proportional bias. The majority of participants were very satisfied with the use of videoconferencing as an application for cognitive assessment and high levels of participant compliance were observed.In this non-clinical cohort home-based videoconference administration of the WAIS-IV was feasible, reliable and acceptable. TNP may offer an alternative for those consumers where there are challenges in accessing a face-to-face service delivery model, thereby improving equity, and enabling continuation of service delivery. Future research is needed with a larger and more ethnically diverse clinical population.

The Precipitous Decline in Reasoning and Other Key Abilities with Age and Its Implications for Federal Judges.

U. S. Supreme Court justices and other federal judges are, effectively, appointed for life, with no built-in check on their cognitive functioning as they approach old age. There is about a century of research on aging and intelligence that shows the vulnerability of processing speed, fluid reasoning, visual-spatial processing, and working memory to normal aging for men and women at all levels of education; even the maintained ability of crystallized knowledge declines in old age. The vulnerable abilities impact a person's decision-making and problem solving; crystallized knowledge, by contrast, measures a person's general knowledge. The aging-IQ data provide a rationale for assessing the key cognitive abilities of anyone who is appointed to the federal judiciary. Theories of multiple cognitive abilities and processes, most notably the Cattell-Horn-Carroll (CHC) model, provide a well-researched blueprint for interpreting the plethora of findings from studies of IQ and aging. Sophisticated technical advances in test construction, especially in item-response theory and computerized-adaptive testing, allow for the development of reliable and valid theory-based tests of cognitive functioning. Such assessments promise to be a potentially useful tool for evaluating federal judges to assess the impact of aging on their ability to perform at a level their positions deserve, perhaps to measure their competency to serve the public intelligently. It is proposed that public funding be made available to appoint a panel of experts to develop and validate an array of computerized cognitive tests to identify those justices who are at risk of cognitive impairment.

Forma corta de cuatro subtest de la WAIS-IV para la evaluación de pacientes con diagnóstico de esquizofrenia / Four-subtest short-form of the WAIS-IV for assessment of patients diagnosed with schizophrenia

Introducción: El objetivo de este estudio ha sido obtener una forma corta de la versión española de la WAIS-IV para pacientes con diagnóstico de esquizofrenia que necesite entorno a media hora para ser administrada. Una forma abreviada puede ser muy útil en contextos clínicos y de investigación cuando se necesite una estimación del cociente intelectual de pacientes con diagnóstico de esquizofrenia para su adscripción a programas de intervención o para la descripción de la muestra.Materiales y métodosParticipó en el estudio una muestra de 143 pacientes. Noventa y uno formaron el grupo de test, y los otros 52 se utilizaron en un análisis de validación cruzada. Para aumentar la validez de contenido, se tomó la decisión de crear una forma corta compuesta por un subtest de cada uno de los 4 dominios cognitivos que mide la escala.ResultadosVarios análisis mostraron que la mejor combinación era la compuesta por los subtest: Información, Cubos, Aritmética y Búsqueda de Símbolos. Se calcularon 9 criterios diferentes para evaluar la calidad de esta forma corta.ConclusionesLos datos mostraron muy buenos resultados en los criterios basados en las correlaciones, las diferencias de medias y la validación cruzada, y resultados satisfactorios en los criterios de acuerdos en la categoría, margen de error, precisión clínica y fiabilidad. (AU)

Introduction: The present study aimed to obtain a short form of the Spanish version of the WAIS-IV for patients diagnosed with schizophrenia that requires about half an hour to be administered. The reduced test can be very useful in clinical and research settings when an estimation of the intelligence quotient is required to decide about intervention programmes or to describe the sample.Materials and methodsA sample of 143 patients participated in the study, 91 out of them were the test group, and the other 52 were used for a cross-validation analysis. To increase the content validity, the decision was made to create a short form composed of a subtest of each of the four cognitive domains that the scale measures.ResultsSeveral analyses showed that the best combination was composed of the Information, Block Design, Arithmetic, and Symbol Search subtests. Nine different criteria were calculated to evaluate the quality of the short form.ConclusionsThe data showed very good results for the criteria: correlations, difference of means, and cross-validation. The results were satisfactory for: category agreement, band of error, clinical accuracy, and reliability. (AU)

Improvement of Working Memory and Processing Speed in Patients over 70 with Bilateral Hearing Impairment Following Unilateral Cochlear Implantation.

Several studies demonstrated the association of hearing disorders with neurocognitive deficits and dementia disorders, but little is known about the effects of auditory rehabilitation on the cognitive performance of the elderly. Therefore, the research question of the present study was whether cochlear implantation, performed in 21 patients over 70 with bilateral severe hearing impairment, could influence their cognitive skills. The measuring points were before implantation and 12 months after the first cochlear implant (CI) fitting. Evaluation of the working memory (WMI) and processing speed (PSI) was performed using the Wechsler Adult Intelligence Scale 4th edition (WAIS-IV). The audiological assessment included speech perception (SP) in quiet (Freiburg monosyllabic test; FMT), noise (Oldenburg sentence test; OLSA), and self-assessment inventory (Oldenburg Inventory; OI). Twelve months after the first CI fitting, not only the auditory parameters (SP and OI), but also the WMI and PSI, improved significantly (p < 0.05) in the cohort. The presented results imply that cochlear implantation of bilaterally hearing-impaired patients over 70 positively influences their cognitive skills.

Four-subtest short-form of the WAIS-IV for assessment of patients diagnosed with schizophrenia.

INTRODUCTION: The present study aimed to obtain a short form of the Spanish version of the WAIS-IV for patients diagnosed with schizophrenia that requires about half an hour to be administered. The reduced test can be very useful in clinical and research settings when an estimation of the intelligence quotient (IQ) is required to decide about intervention programs or to describe the sample. MATERIALS AND METHODS: A sample of 143 patients participated in the study, 91 out of them were the test group, and the other 52 were used for a cross-validation analysis. To increase the content validity, the decision was made to create a short form composed of a subtest of each of the four cognitive domains that the scale measures. RESULTS: Several analyses showed that the best combination was composed of the Information, Block Design, Arithmetic, and Symbol Search subtests. Nine different criteria were calculated to evaluate the quality of the short form. CONCLUSIONS: The data showed very good results for the criteria: correlations, difference of means, and cross-validation. The results were satisfactory for: category agreement, band of error, clinical accuracy, and reliability.

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.

Investigating the Structure of Intelligence Using Latent Variable and Psychometric Network Modeling: A Commentary and Reanalysis.

In a recent publication in the Journal of Intelligence, Dennis McFarland mischaracterized previous research using latent variable and psychometric network modeling to investigate the structure of intelligence. Misconceptions presented by McFarland are identified and discussed. We reiterate and clarify the goal of our previous research on network models, which is to improve compatibility between psychological theories and statistical models of intelligence. WAIS-IV data provided by McFarland were reanalyzed using latent variable and psychometric network modeling. The results are consistent with our previous study and show that a latent variable model and a network model both provide an adequate fit to the WAIS-IV. We therefore argue that model preference should be determined by theory compatibility. Theories of intelligence that posit a general mental ability (general intelligence) are compatible with latent variable models. More recent approaches, such as mutualism and process overlap theory, reject the notion of general mental ability and are therefore more compatible with network models, which depict the structure of intelligence as an interconnected network of cognitive processes sampled by a battery of tests. We emphasize the importance of compatibility between theories and models in scientific research on intelligence.

Gender differences on the WAIS-IV in patients with schizophrenia / Diferencias de género en la WAIS-IV en pacientes con esquizofrenia

Abstract Introduction Results from studies that have investigated gender differences in neuropsychological functioning in schizophrenia have been inconsistent. Differences in the illness stage, in the demographic and clinical characteristics of the samples, and the instruments used to measure cognition may have contributed to the heterogeneity in the results. Objective Investigate the heterogeneity in the results comparing cognitive functioning in chronically ill male and female patients with schizophrenia. Method Twenty-five women and twenty-five men chronically ill patients with schizophrenia matched on age, age at illness onset, and years of education were evaluated in cognitive functioning using the WAIS-IV. Results Men showed higher scores than women on the two global measures, on the perceptual reasoning and working memory indices, and on the information, visual puzzles, digit span, and arithmetic subtests of the WAIS-IV. Cohen's d effect sizes were high for the two global measures and the two indices (d > .68). Discussion and conclusion Overall, in chronically stable patients with diagnosis of schizophrenia, women's performance on cognitive functioning was below men's when assessed with the WAIS-IV, except in the case of processing speed. This pattern of gender differences is similar to the pattern observed in healthy populations. Our results can help to clarify the heterogeneity in the results from studies on gender differences in cognitive functioning in schizophrenia and may be valuable in designing cognitive-targeted interventions for schizophrenia.

Resumen Introducción Los resultados de los estudios que han investigado diferencias de género en funcionamiento neuropsicológico en la esquizofrenia han sido inconsistentes. Diferencias en la fase de la enfermedad, en las características demográficas y clínicas de las muestras y en los instrumentos utilizados podrían explicar esa heterogeneidad. Objetivo Investigar la heterogeneidad en los resultados comparando el funcionamiento cognitivo de pacientes con diagnostico de esquizofrenia. Método Veinticinco mujeres y veinticinco hombres pacientes con diagnóstico de esquizofrenia equiparados en edad, edad al inicio de la enfermedad y nivel educativo se evaluaron en funcionamiento cognitivo utilizando la WAIS-IV. Resultados Los hombres mostraron puntuaciones más altas que las mujeres en las dos medidas globales, en los índices de razonamiento perceptivo y de memoria de trabajo y en las subtests de la WAIS-IV de información, puzles visuales, amplitud de dígitos y aritmética. Los tamaños de efecto d de Cohen fueron altos en las dos medidas globales y en los dos índices (d > .68). Discusión y conclusión En conjunto, la ejecución de las mujeres en funcionamiento cognitivo está por debajo de la de los hombres cuando se mide con la WAIS-IV, excepto en el caso de la velocidad de procesamiento. Este patrón de diferencias de género es similar al patrón observado en población sana. Nuestros resultados pueden ayudar a clarificar la heterogeneidad de resultados en los estudios sobre diferencias de género en el funcionamiento cognitivo en la esquizofrenia y podrían ser útiles en el diseño de intervenciones centradas en la cognición.