ABSTRACT Associations Between Sleep and Memory in a Clinical Sample of Obese Children and Adolescents Natalie M. Passanante, Psy.D. Mentor: Christine A. Limbers, Ph.D. Today more than one third of U. S. children and adolescents are classified as overweight or obese. While interventions have produced short term improvements in weight status, treatment effects are infrequently maintained. Standard interventions may not be well-suited for the cognitive profile associated with obesity, which is characterized by impaired executive functioning. The literature on memory consolidation during sleep suggests that sleep problems associated with obesity may contribute to this cognitive profile in ways that have yet to be elucidated. The present study examined the associations between sleep and multiple indices of memory in a clinical sample of 45 obese children and adolescents. Sleep was assessed from both child and parent perspectives. Memory was evaluated using the Wide Range Assessment of Memory and Learning, Second Edition (WRAML2). Multiple linear regression analyses revealed that sleep duration and sleep quality explained the most variation in visual memory abilities. The results underscore the importance of early intervention in childhood obesity and illuminate the importance of targeting sleep as a component of weight loss interventions. Associations Between Sleep and Memory in a Clinical Sample of Obese Children and Adolescents by Natalie M. Passanante, B.A., M.S.C.P. A Dissertation Approved by the Department of Psychology and Neuroscience ____________________________________________________ Jaime L. Diaz-Granados, Ph.D., Chairperson Submitted to the Graduate Faculty of Baylor University in Partial Fulfillment of the Requirements for the Degree of Doctor of Psychology Approved by the Dissertation Committee _________________________________________ Christine A. Limbers, Ph.D., Chairperson _________________________________________ Gary R. Elkins, Ph.D. _________________________________________ Charles A. Weaver, Ph.D. _________________________________________ Renee Umstattd-Meyer, Ph.D. _________________________________________ JoAnn Tsang, Ph.D. Accepted by the Graduate School August 2014 _________________________________________ J. Larry Lyon, Ph.D., Dean Page bearing signatures is kept on file in the graduate school. Copyright © 2014 by Natalie M. Passanante All rights reserved TABLE OF CONTENTS Introduction .........................................................................................................................1 Childhood Obesity ...............................................................................................................1 Interventions for Childhood Obesity ...................................................................................2 Biological Correlates of Cognitive Differences in Obesity .....................................3 Cognitive Profile Associated With Obesity: Executive Functioning ......................4 Memory ...................................................................................................................5 Sleep and Memory ...................................................................................................8 Sleep Duration and Obesity .....................................................................................9 Biological Mechanisms for Relationship Between Short Sleep Duration and Obesity ................................................................................................................11 Sleep Disordered Breathing ...................................................................................12 Other Sleep-Related Concerns, Cognitive and Memory Correlates ......................16 Purpose of the Present Study .................................................................................17 Hypotheses .............................................................................................................18 Method ...............................................................................................................................20 Participants .............................................................................................................20 Table 1. Demographic Characteristics of Study Participants ................................21 Procedures ..............................................................................................................22 Measures ................................................................................................................25 Body Mass Index .......................................................................................25 Parent Report of Child Sleep .....................................................................25 Table 2. Average Parent Reports and Actigraphic Recordings of Sleep Duration and Related Behaviors .............................................................29 Child Self-Report of Sleep .........................................................................29 School Performance ...................................................................................30 Memory ......................................................................................................32 Intelligence .................................................................................................33 Data Analysis .........................................................................................................33 Figure 1. Schematic of Model for Hierarchical Regression Analysis ...................35 Results ................................................................................................................................36 Verbal Memory Index ............................................................................................36 Visual Memory Index ............................................................................................36 Attention/Concentration .........................................................................................37 Table 3. Hierarchical Regression Analysis of Sleep Measures and Memory Function in Obese Youth ....................................................................................38 Agreement Between Parent and Child Sleep Measures .........................................39 iv Table 4. Correlations Between Total Scores and Corresponding Items of the Children’s Sleep Habits Questionnaire-Abbreviated (CSHQ-A) and Sleep Self- Report..................................................................................................................39 Discussion ..........................................................................................................................41 Verbal Memory Index Scores ................................................................................41 Visual Memory Index Scores.................................................................................42 Attention/Concentration Index Scores ...................................................................43 Parent-Child Agreement ........................................................................................45 Clinical Implications ..............................................................................................46 Strengths/Limitations .............................................................................................49 Future Directions ...................................................................................................52 Appendices .........................................................................................................................56 A—Children’s Sleep Habits Questionnaire Items By Subscale ............................57 B—Children’s Sleep Habits Questionnaire (Abbreviated) ....................................59 C—Sleep Self Report .............................................................................................61 References ..........................................................................................................................62 v LIST OF FIGURES 1. Schematic of Model for Hierarchical Regression Analysis ..........................................35 vi LIST OF TABLES 1. Demographic Characteristics of Study Participants .....................................................21 2. Average Parent Reports and Actigraphic Recordings of Sleep Duration and Related Behaviors .......................................................................................................................29 3. Hierarchical Regression Analysis of Sleep Measures and Memory Function in Obese Youth .............................................................................................................................38 4. Correlations Between Total Scores and Corresponding Items of the Children’s Sleep Habits Questionnaire-Abbreviated (CSHQ-A) and Sleep Self-Report .........................39 vii CHAPTER ONE Introduction Childhood Obesity The number of obese children in the United States (U.S.) has tripled over the past thirty years (Ogden, Carroll, Curtin, Lamb, & Flegal, 2010). Today the Centers for Disease Control and Prevention report that more than one third of U.S. children and adolescents are classified as overweight or obese (CDC, 2013). There are a number of adverse medical conditions associated with childhood obesity including high cholesterol and triglycerides, hypertension (Freedman, Dietz, Srinivasan, & Berenson, 1999), insulin resistance (Shaibi & Goran, 2008),