Date of Award

7-31-2014

Document Type

Dissertation

Degree Name

Doctor of Psychology (PsyD)

Department

Psychology

First Advisor

David J. LaPorte, Ph.D.

Second Advisor

William Meil, Ph.D.

Third Advisor

Margaret Reardon, Ph.D.

Fourth Advisor

Donald U. Robertson, Ph.D.

Fifth Advisor

Michael Franzen, Ph.D.

Abstract

The Iowa Gambling Task (IGT) has been used as a measure of decision-making among many clinical populations. However, not much is known about IGT performance in individuals with traumatic brain injury (TBI) and diagnoses of psychological distress. Additionally, evidence on convergent and divergent validity with other measures is lacking in the literature. Archival neuropsychological evaluation data from 74 outpatients at an academic medical hospital were collected. This study investigated convergent validity of the IGT to other executive functioning tasks in those with TBI. Data was analyzed through the use of a regression analysis. Results demonstrated that measures of executive functioning did not significantly predict scores on blocks 1 and 2 of the IGT (R2 =.29, F (5, 27)= 2.17, p= .087). Contrary to what was hypothesized, scores on measures of executive functioning did not predict the scores on blocks 3, 4, and 5 of the IGT (R2 = .18, F (5, 27)= 1.17 p= .350). Second, this study compared performance on the IGT in those with a diagnosis of psychological distress who also have a TBI to those with no history of TBI but have a diagnosis of psychological distress. This was accomplished through the use of a t-test. There was no significant difference in performance between the groups on the IGT NET score t(72)= -2.10, p= .323. Third, this study examined convergent and divergent validity of the IGT NET across all subjects by calculating Pearson correlations on the IGT NET score with scores on measures of delayed memory, visual perception, and executive functioning. The IGT NET score significantly correlated with the score on the COWAT (r=.25, N=74, p=.034), Trails B (r=.36, N= 74, p= .001), categories completed on the Wisconsin Card Sorting Test (r=.27, N= 74, p= .022), and Judgment of Line Orientation Test (r =.28, N=67, p=.021). The IGT Net score did not show significant correlations with Verbal Paired Associates II (r=.19, N=73, p=.103) or the score from Logical Memory II (r=.18, N=74, p=.120). Exploratory analyses for each hypothesis were also run. Explanation of the data, interpretation of the findings, limitations, and directions for future studies are discussed.

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