Monday, May 10, 2010

Dissertation Dish: Cognitive tests and brain white matter volume and review of common achievement tests

Conduits of cognition Neuropsychological correlates of cerebral white matter volume in healthy children and adolescents by Shmidheiser, Maximillian H., Psy.D., Widener University, Institute for Graduate Clinical Psychology, 2008 , 121 pages; AAT 3405214

This study was an empirical analysis of the relationship between cerebral white matter volume and measures of intelligence, attention, processing speed and academic achievement among healthy children and adolescents. To date, there have been no studies that correlated a broad range of cognitive measures in relation to volumetric measurements of white matter via Magnetic Resonance Imaging (MRI) in healthy children and adolescents. This study sought to explore the supposition set forth by previous research, especially with regard to children treated with radiation therapy for cancer, that white matter is the neuroanatomical substrate that can account for variation in performance on select cognitive tasks. Additionally, the purpose of this study was to generate further hypotheses and research questions pertaining to key relationships between cerebral white matter volume and cognition in childhood and adolescence.

This study draws on a dataset created by the recent NIH MRI Study of Normal Brain Development, which utilized a large and demographically representative sample of children and adolescents. Archival cognitive data were drawn from select subtests of the Wechsler Abbreviated Scales of Intelligence (WASI), Wechsler Intelligence Scales for Children - III (WISC-III), Woodcock Johnson - III (WJ-III), and the Cambridge Neuropsychological Test Automated Battery (CANTAB). Volumetric measurements of white matter volume were obtained using archival magnetic resonance imaging data. Significant correlations between white matter volume and WASI Block Design, WASI Matrix Reasoning, CANTAB Spatial Span, and WJ-III Passage Comprehension were found; however, follow-up regression analyses revealed that white matter volume was a predictor only for WASI Block Design and WJ-III Passage Comprehension. The results of this study suggest that, in a healthy population of children and adolescents, white matter volume may be related to those academic and intelligence abilities that are complex and dependent upon the integration of disparate cortical regions.

A review of academic achievement tests: Recommendations for age appropriate administration by Kozloff, Allison Burstein, Psy.D., Widener University, Institute for Graduate Clinical Psychology, 2009 , 83 pages; AAT 3405220


Comprehensive academic achievement tests are routinely used by school psychologists in psycho-educational assessment batteries to identify learning disabled students. A variety of assessment measures are used across age groups to determine if a discrepancy exists between academic achievement and intellectual functioning; however, among the most commonly used tests there are limitations as to how well they can accurately detect this discrepancy. This failure is due, in part, to test construction problems such as item gradient steepness that negatively impacts floor and ceiling effects. These construction problems are particularly salient with certain age ranges, indicating that the accuracy of these tests will vary depending on the age of the child being tested. This dissertation will review test construction issues for the most predominant comprehensive academic achievement tests, the Wechsler Individual Achievement Test - Second Edition (WIAT-II), the Woodcock-Johnson III Tests of Achievement (WJ-III ACH), and the Kaufman Test of Educational Achievement - Second Edition (KTEA-II), to determine the test most suitable for a particular age group.

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