Recognition Memory Impairments in Temporal Lobe Epilepsy: the Contribution of Recollection and Metacognition
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Recognition memory impairments in temporal lobe epilepsy: The contribution of recollection and metacognition Nathan Anthony Illman Submitted in accordance with the requirements for the degree of Doctor of Philosophy The University of Leeds Institute of Psychological Sciences, Faculty of Medicine and Health September 2012 The candidate confirms that the work submitted is his own and that appropriate credit has been given where reference has been made to the work of others. This copy has been supplied on the understanding that it is copyright material and that no quotation from the thesis may be published without proper acknowledgement. ©2012 The University of Leeds and Nathan Anthony Illman ii ACKNOWLEDGEMENTS First and foremost, I must thank my main academic supervisor – Chris Moulin. I cannot express just how much I have valued his help, support, guidance and friendship throughout the course of my post-graduate studies at the University of Leeds. Having someone truly believe in me every step of the way has allowed me to develop the self-confidence that will no doubt be needed through the rest of my career. I would also like to thank my other academic supervisor - Celine Souchay. Although I didn’t approach her for guidance on many occasions, her support was always appreciated and I found comfort knowing that I could ask her for help when needed. My thanks go to Dr Steven Kemp for being so accommodating with involving me in his clinics and making the effort to teach me about epilepsy. I will always appreciate how he treated me like a professional colleague and not just a student. A special thanks also goes to Dr Peter Goulding, Nurses Lizzie Wright and Joe Geldard and Epilepsy Action Charity, who helped me with recruitment. This also goes to all the participants who kindly volunteered their time to help with my research. All of these people helped me transform an ambitious idea into a reality. I want to thank the other PG students in my year that I have been lucky enough to spend time with over the course of my PhD. A truly amazing bunch of people who I will never forget. I must also thank Zoe Jay-Chessell for her help with data collection toward the end of my project. This thesis is dedicated to my family – Big Jane, Big Nige, Matt and Grandma. Their love and support has helped me achieve my goals in life so far. iii ABSTRACT Temporal lobe epilepsy (TLE) is a complex neurological condition associated with a variety of memory problems. This thesis attempted to elucidate the nature and extent of memory impairments further in this clinical group by drawing on dual-process theory of memory (Tulving, 1985; Jacoby, 1991; Yonelinas, 1994). This theory asserts that memory is subserved by two interrelated but independent memory processes. Recollection involves the vivid retrieval of contextual and associative information from memory. Conversely, familiarity involves recognition in the absence of this contextual information. The novel approach taken in this work was to compare paradigms that assess participants’ objective and strategic use of these two processes with measures of people’s subjective experience of their memory. Chapter 2 set the scene by presenting the extent of objective memory impairment in the current patient sample by means of standardised neuropsychological testing. Chapter 3 – 5 assessed subjective and objective recollection in anterograde recognition memory tasks. Chapter 3 showed that patients’ subjective experience of remembering may be driven by qualitatively different types of information to healthy adults. Chapter 4 demonstrated that patients were impaired in their strategic use of recollection and concurrently showed reduced levels of subjective remembering. This demonstrated that patients can be consciously aware of deficits in underlying cognitive processes contributing to memory performance. Chapter 5 specifically examined a metacognitive account of this recollection deficit. Patients were found to have impairments in a number of measures that index relational binding ability. However, their subjective confidence was assigned appropriately; they were lesser confident in their recognition judgments overall and adjusted this confidence in line with the difficulty of materials and task demands comparably to controls. Chapter 6 took a more naturalistic approach and assessed self-reported memory complaint as well as retrograde memory for salient public news events. As expected, people with TLE subjectively complained of dissatisfaction with their day-to-day to memory. The public events task revealed that although patients had reductions in subjective measures associated with recollecting the events, they were just as able as controls to accurately date the news items and monitor their memory for these. Chapter 7 found correlations between a variety of the subjective and objective recollection scores derived in the various tasks. This thesis provides confirmatory evidence that memory impairment in TLE is characterised by disordered recollection and recollective experience. Several important theoretical and clinical applications of these findings are discussed. iv TABLE OF CONTENTS Acknowledgements…………………………………………………………………………………………………………………ii Abstract…………………………………………………………………………………………………………………………………..iii Contents………………………………………………………………………………………………………………………………....iv Figures…………………………………………………………………………………………………………………………………….ix Tables……………………………………………………………………………………………………………………………………….x Abbreviations………………………………………………………………………………………………………………………….xii 1 Introduction ............................................................................................................. 1:1 1.1 Overview .................................................................................................................... 1:1 1.2 Temporal lobe epilepsy .............................................................................................. 1:2 1.3 Temporal lobe seizures and memory ........................................................................ 1:3 1.4 The consequences of TLE ........................................................................................... 1:4 1.5 Neuropsychological assessment of TLE ..................................................................... 1:5 1.5.1 Lateralisation and the material specificity principle .......................................... 1:6 1.6 The clinical context: Differences between patients’ subjective memory reports and neuropsychological assessment ............................................................................................ 1:8 1.7 Recollection and Familiarity ....................................................................................... 1:9 1.8 Dual-process theories .............................................................................................. 1:10 1.8.1 Tulving and the Remember/Know paradigm ................................................... 1:11 1.8.2 Jacoby and the process-dissociation procedure .............................................. 1:12 1.8.3 Yonelinas and the dual-process signal detection model ................................. 1:13 1.8.4 Alternatives to dual-process models ............................................................... 1:14 1.8.4.1 Single trace accounts ................................................................................... 1:14 1.8.4.2 The Source Monitoring Framework ............................................................. 1:15 1.8.5 Neuroanatomical models ................................................................................. 1:16 1.8.5.1 Dual- process neuroanatomical accounts of recognition memory .............. 1:17 1.8.5.2 The single trace neuroanatomical account of recognition memory ............ 1:19 1.8.6 Consolidation theories of hippocampal function ............................................ 1:20 1.8.6.1 The Standard Model of Consolidation ......................................................... 1:21 1.8.6.2 The Multiple Trace theory............................................................................ 1:22 1.8.7 Summary .......................................................................................................... 1:22 1.9 Measuring recollection and familiarity .................................................................... 1:23 v 1.9.1 Subjective measures and awareness ............................................................... 1:23 1.9.1.1 The R/K paradigm ......................................................................................... 1:23 1.9.2 Objective measures .......................................................................................... 1:24 1.9.2.1 Item vs. associative memory ........................................................................ 1:24 1.9.2.2 Source memory ............................................................................................ 1:25 1.9.2.3 Process estimations ..................................................................................... 1:26 1.9.2.4 ROC method ................................................................................................ 1:28 1.9.3 Theoretical considerations and boundary conditions of methods .................. 1:31 1.9.3.1 Process Dissociation Procedure ................................................................... 1:31 1.9.3.2 R/K paradigm ............................................................................................... 1:32 1.10 Recollection and familiarity in TLE ..........................................................................