The Estimation of Premorbid Intelligence: a Comparison of Approaches
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Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1999 The Estimation of Premorbid Intelligence: a Comparison of Approaches. Peter Anthony Petito Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Petito, Peter Anthony, "The Estimation of Premorbid Intelligence: a Comparison of Approaches." (1999). LSU Historical Dissertations and Theses. 7120. https://digitalcommons.lsu.edu/gradschool_disstheses/7120 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. 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Higher quality 6“ x 9" black and vtfiite photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. Bell & Howell Information and Learning 300 North Zeeb Road, Ann Arbor, Ml 48106-1346 USA 800-521-0600 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. THE ESTIMATION OF PREMORBID INTELLIGENCE: A COMPARISON OF APPROACHES A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements for the degree of Doctor of Philosophy in The Department of Psychology by Peter Anthony Petito B. S., University of Arizona, 1984 M. A., Louisiana State University, 1987 December 1999 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number. 9960091 UMI* UMI Microform9960091 Copyright 2000 by Bell & Howell Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. Bell & Howell Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGMENTS The author wishes to thank the chair of his committee, W. Drew Gouvier, PhD, who provided expertise, patience, and a lifetime of support throughout the life of this project. Special thanks to Dr. Kerry Sauley for his guidance and expertise for the statistics in this project. The author also wishes to express his gratitude to the other members of his committee—Drs. William Waters, A rthur Riopelle, and David Reitman—for their time, expertise, and invaluable advice in the preparation of this manuscript. Gratitude must also be expressed to the Rehabilitation Psychology staff at Loma Linda University Medical Center for their patience and guidance during this process. Finally, the author wishes to thank his wife Mary and his parents and in-laws for their love and support. ii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Acknowledgments ............................................................... ii List of T ables ............................................................................................................. v List of Figures........................................................................................................... vi A bstract.....................................................................................................................vii Introduction and literature review ..........................................................................1 Estimation Procedures Based on Current Performance ........................ 3 Demographic Variable-Based Estimation Procedures ..........................12 Com bined Predictor Estim ation P ro ced u res ............................................21 The Present Study ...................................................................................... 25 M ethods .................................................................................................................... 28 S ubjects......................................................................................................... 28 M aterials ..................................................................................................... 31 P rocedures .................................................................................................... 32 Data Analyses ............................................................................................. 32 R e s u lts......................................................................................................................37 Hypothesis 1 ................................................................................................37 Hypothesis 2 ................................................................................................ 45 Hypothesis 3 ................................................................................................ 46 D iscussion .................................................................................................................62 R eferences ................................................................................................................70 A ppendices Appendix A: Word List of the National Adult Reading Test ............. 76 Appendix B: Regression Equations Developed by Vanderploeg a n d Schinka (1 9 9 5 ) ......................................................................... 77 Appendix C: Medical and Psychological Screening for Control S u b je c ts............................................................................................ 78 Appendix D: Consent Form for Head-Injured Subjects ....................... 79 iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Appendix E: Consent Farm for Volunteer Subjects V ita .................................................................................... iv Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LEST OF TABLES Table 1: Demographic Characteristics of the Subject G roups........................ 30 Table 2: Obtained WAES-R IQs for the Experimental (CHI) and Control G roups.......................................................................................................... 38 Table 3: Estimated WAES-R IQs using the Friedberg & Gouvier (1996) Equations ................................................................................................... 40 Table 4: Estimated WAES-R IQs using the Vanderploeg & Schinka (1995) Equations ................................................................................................... 42 Table 5: Estimated IQs using the averaged Vanderploeg & Schinka (1995) E quations..................................................................................................... 44 Table 6: Discrepancies between Obtained and Estimated WAES-R IQ 47 Table 7: Regression Summary Table for Friedberg & Gouvier (1996) E quations..................................................................................................... 49 Table 8: Regression Summary Table for Vanderploeg & Schinka (1995) E quations..................................................................................................... 51 Table 9: Regression Table of Comparisons for Friedberg & Gouvier (1996) and Vanderploeg & Schinka (1995) Equations .......................................53 Table 10: Correlations of estimated versus obtained IQ scores ................. 61 v Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LEST OF FIGURES Figure 1: Scatterplot of actual VIQ scores relative to predicted scores for CHI su b jects........................................................................................... 55 Figure 2: Scatterplot of actual VIQ scores relative to predicted scores for norm al su b jects ....................................................................................... 56 Figure 3: Scatterplot of actual PIQ scores relative to predicted scores for CHI subjects...........................................................................................57 Figure