Sunday, September 04, 2011

Dissertation Dish: Two new neuropsych studies involving WJ III, D-KEFS and NEPSY




Examining the concurrent validity of visual and auditory attention tasks of the D-KEFS, NEPSY, and WJ III COG using structural equation modeling
by Mortimer, Jordana E., Ph.D., Texas Woman's University, 2011 , 247 pages; AAT 3464568

Abstract

Attention is a broad cognitive function that is thought to be a foundational skill necessary for all other neurocognitive operations. Differences in theoretical orientations have led to a lack of consensus regarding a specific definition of attention. Because attention theories have a direct impact upon cognitive assessments, continued debate has resulted in a failure to establish appropriate tasks which measure attention constructs. The purpose of this study was to determine the concurrent validity of the attention subscales of three commonly administered neurocognitive instruments: the Woodcock Johnson III Tests of Cognitive Abilities (WJ III COG; Woodcock, McGrew, & Mather, 2001c; Woodcock et al., 2007), the NEPSY: A Development Neuropsychological Assessment (Korkman, Kirk, & Kemp, 1998), and the Delis-Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001). Additionally, this study examined the underlying factor structure of the D-KEFS, NEPSY, and WJ III COG, and their fit with four theories of attention. The four theories which were analyzed are Mirsky and colleagues' (1991) model of attention, the Cattell-Horn-Carroll model of cognitive abilities (CHC theory; McGrew, 2005), the Conceptual Model for School Neuropsychological Assessment (SNP model; Miller, 2007, 2010), and a model which examines tasks based on auditory and visual modalities. Data was extracted from archival case studies submitted to the KIDS, Inc.'s School Neuropsychology Post-Graduate Certification Program, which included a mixed clinical sample of children, age 8 through 12. Correlations were utilized to determine relationships among attention subtests. Some evidence demonstrated similar internal consistency of the attention subtests within both the WJ III COG and the NEPSY. Less evidence was provided in support of the internal validity of the D-KEFS. Relationships between the theories and attention subtests were examined using structural equation modeling. Confirmatory factor analysis (CFA) was conducted to determine how well the various attention theories fit with the attention subtests. Results from the CFA, demonstrated the model which assessed attention using visual and auditory modalities indicated the best fit with the sample data when compared to the other models. Limitations of the current investigation as well as suggestions for future studies are also discussed.



Validity of executive functioning tasks across the WJ III COG, NEPSY, and D-KEFS in a clinical population of children: Applicability to three neurocognitive theoriesby Avirett, Erin K., Ph.D., Texas Woman's University, 2011 , 244 pages; AAT 3464570

Abstract

Inconclusive research regarding the neurocognitive construct of executive functioning has restricted the development of valid pediatric executive functioning assessments (Floyd et al., 2006: Maricle, Johnson, & Avirett, 2010). Misunderstandings in the research have led to divergent executive functioning theories and assessment tasks. Therefore. it cannot be assumed that all executive functioning instruments are measuring the same construct. Given the common inclusion of executive functioning tasks in pediatric neuropsychological evaluations (Stuss & Alexander, 2000), it is important to determine the validity of executive functioning theories and assessment tools. Furthermore, because these evaluations are often administered to children with clinical diagnoses, it is important to assess validity issues with this group. Therefore, this study aimed to determine the concurrent validity of the executive functioning subscales of three commonly utilized neurocognitive instruments: the Woodcock Johnson III Tests of Cognitive Abilities (WJ III COG; Woodcock, McGrew, & Mather, 2001c), the NEPSY (Korkman, Kirk, & Kemp, 1998), and the Delis Kaplan Executive Function System (D-KEFS; Delis, Kaplan, & Kramer, 2001). An associated purpose of this study was to determine the underlying factor structure of the WJ III COG, NEPSY, and D-KEFS, and their fit with three theories of executive functioning. The three theories that were analyzed include the Anderson, Levin, and Jacob (2002) model of executive functioning, the Cattell-Horn-Carroll theory of cognitive abilities (CHC theory; McGrew, 2005), and the Conceptual Model for School Neuropsychological Assessment (SNP model; Miller, 2007, 2010). Archival data was extracted from school neuropsychology case study reports. Children from a clinical sample, aged 8 through 12, were included in the study. Bivariate correlations were conducted in order to determine relationships among executive functioning subtests. These analyses revealed that executive functioning subtests appear to be measuring distinct abilities and are not interchangeable. Furthermore; the reliable use of most of these subtests within a clinical population was indicated. Level of fit between executive functioning models and sample data was depicted using structural equation modeling and analyzed using confirmatory factor analysis. The SNP conceptual model indicated the best fit with sample data.



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