Saturday, April 24, 2010

Research Bytes 4-24-10: WISC-IV & TBI and WAIS-IV factor study research studies

Allen, D. N., Thaler, N. S., Donohue, B., & Mayfield, J. (2010). WISC-IV Profiles in Children With Traumatic Brain Injury: Similarities to and Differences From the WISC-III. Psychological Assessment, 22(1), 57-64.

The Wechsler Intelligence Scale for Children—Fourth Edition (WISC–IV; D. Wechsler, 2003a) is often utilized to assess children with traumatic brain injury (TBI), although little information is available regarding its psychometric properties in these children. The current study examined WISC–IV performance in a sample of 61 children with TBI. As compared to the standardization sample, results indicated that the TBI group exhibited relative deficits on all subtest and index scores, with the greatest deficits on the Processing Speed Index (PSI) and Coding subtest scores. However, the Perceptual Reasoning Index score was not uniquely sensitive to brain injury, and the Cognitive Processing Index score was less sensitive to TBI than the PSI score. Also, the PSI did not uniquely predict learning and memory abilities, as had been reported in previous studies of the Wechsler Intelligence Scale for Children—Third Edition (WISC–III; D. Wechsler, 1991). The present findings indicate substantive differences between the WISC–III and WISC–IV profiles of children with TBI.

Benson, N., Hulac, D. M., & Kranzler, J. H. (2010). Independent Examination of the Wechsler Adult Intelligence
Scale-Fourth Edition (WAIS-IV): What Does the WAIS-IV Measure? Psychological Assessment, 22(1),

Published empirical evidence for the Wechsler Adult Intelligence Scale—Fourth Edition (WAIS–IV) does not address some essential questions pertaining to the applied practice of intellectual assessment. In this study, the structure and cross-age invariance of the latest WAIS–IV revision were examined to (a) elucidate the nature of the constructs measured and (b) determine whether the same constructs are measured across ages. Results suggest that a Cattell–Horn–Carroll (CHC)–inspired structure provides a better description of test performance than the published scoring structure does. Broad CHC abilities measured by the WAIS–IV include crystallized ability (Gc), fluid reasoning (Gf), visual processing (Gv), short-term memory (Gsm), and processing speed (Gs), although some of these abilities are measured more comprehensively than are others. Additionally, the WAIS–IV provides a measure of quantitative reasoning (QR). Results also suggest a lack of cross-age invariance resulting from age-related differences in factor loadings. Formulas for calculating CHC indexes and suggestions for interpretation are provided.

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