Replication of the factor structure of the Wechsler Adult Intelligence Scale-Third Edition with a Canadian sample
ABSTRACT Exploratory and confirmatory factor analyses of the subtests of the Wechsler Adult Intelligence Scale--Third Edition (WAIS-III; D. Wechsler, 1997b) were conducted on a stratified sample of Canadian adults (n = 718). As was previously demonstrated for the children's version of this scale, the factor model of the American standardization sample was replicated across this Canadian national sample. Results of the factor analyses confirmed the presence of the 4 WAIS-III factors: Verbal Comprehension, Perceptual Organization, Working Memory, and Processing Speed.
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ABSTRACT: This report examines and compares the factor structure of the new edition of the Wechsler Adult Intelligence Scale (WAIS-III) in a sample of chronic schizophrenia and schizoaffective disorder outpatients (n = 120) and an age-matched sample of individuals drawn from the WAIS-III standardization sample (n = 200). Exploratory and confirmatory factor analyses similar to those reported by the developers of the scale suggested that a model of WAIS-III performance with correlated factors for verbal comprehension, perceptual organization, working memory, and processing speed fit the data from the schizophrenia sample as well as it fit the nonclinical comparison sample and fit the data from both samples better than alternative models.Assessment 07/2002; 9(2):171-80. DOI:10.1177/10791102009002008 · 3.29 Impact Factor
Article: Metamemory in multiple sclerosis[Show abstract] [Hide abstract]
ABSTRACT: The concept of metamemory proposes that supplementary to typically measured memory abilities, memory monitoring and control processes are used to optimise learning. Accurate memory monitoring appears to be underpinned by a range of cognitive, and possibly affective, contributions. In populations with these deficits, metamemory has been shown to be impaired. In Multiple Sclerosis (MS), only a limited metamemory literature exists, surprising given that MS is a leading cause of disability among people of working age, and cognitive and mood disorder is common. Using structural equation modelling, this study of 100 people with MS explored factors contributing to performance on episodic Judgment of Learning, Retrospective Confidence and Feeling of Knowing. Given its negative influence on cognitive domains in MS, the impact of information processing deficits on metamemory was also investigated. Finally, memory self-report, a frequently used clinical indicator of memory functioning, was assessed. Findings suggest that memory complaint is associated with mood, and is unrelated to tested memory. Second, Retrospective Confidence Judgments were predictive of memory performance, even in the presence of memory impairment. Third, an unusual finding of maintained underconfidence at delay was observed in the Judgment of Learning task. Finally, Feeling of Knowing judgments related to executive, but not to memory ability. A novel finding in respect of this judgment was of processing speed relating negatively to accuracy, in the context of executive dysfunction. This suggests that some top-down direction of processing resources may be a factor in supporting accuracy, rather than the speed at which information is processed. Of all the task-based judgments, accuracy in this judgment was the only one with a reliable association with mood. Faster processing speed, executive dysfunction and least depression symptomatology related to low accuracy, perhaps typifying a profile of disinhibition seen in MS, characterised by poorly constrained processing and apparently elevated mood.
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ABSTRACT: El presente trabajo tiene como objetivo obtener una forma abreviada de la versión española del WAISIII que permita, con las garantías suficientes, reducir el tiempo de aplicación de la escala completa. Aunque se utilizaron muestras procedentes tanto de población normal (41 participantes sin patología mental conocida) como de población con diagnóstico de esquizofrenia (41 participantes), realmente el interés estaba centrado en el grupo clínico, ya que en el mismo es donde mayores ventajas se pueden obtener al acortar el tiempo de aplicación de la escala. Los datos mostraron que la mejor combinación de tests fue la de Semejanzas, Figuras Incompletas, Dígitos y Clave de números, ya que con esta forma reducida se obtiene una correlación lineal entre el CI Total de la escala completa y el de la forma abreviada de 0,91 en el grupo clínico y de 0,86 en el control. Para ambos grupos las diferencias entre los CI medios reales y los estimados no fueron significativas.