Canterbury Christ Church University’s repository of research outputs http://create.canterbury.ac.uk Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. Benjamin, Maxwell J. (2013) Autobiographical memory in Alzheimer's Disease. D.Clin.Psych. thesis, Canterbury Christ Church University. Contact: [email protected] Maxwell James Benjamin B.Sc. (Hons)., M.Sc. Autobiographical Memory in Alzheimer’s Disease Section A: Autobiographical memory in Alzheimer’s disease: A review of assessment methods and the evidence base. Word count: 5498 Section B: The role of working memory and verbal fluency in autobiographical memory in early Alzheimer’s disease and matched controls Word count: 7976 Section C: Critical Appraisal Word count: 1931 Overall word count: 15405 A thesis submitted in partial fulfilment of the requirements of Canterbury Christ Church University for the degree of Doctor of Clinical Psychology September 2013 SALOMONS CANTERBURY CHRIST CHURCH UNIVERSITY Acknowledgements Firstly, I would like to extend my gratitude to all the participants who took part in this study, many of whom had also made other research commitments. It was a real privilege to be able to share in their memories. I would also like to thank the clinicians who facilitated recruitment at the various sites for their time and effort. Thanks also go to my supervisors Dr. Diana Caine and Dr. Fergal Jones for their time and patience. Their guidance from the project’s inception to completion was invaluable. I must also thank those peers who provided advice, support and encouragement over these three years. Last, but by no means least, I would like to thank (and apologise to!) my friends and family for tolerating my absences, and Marie, for without her unwavering support and belief, this task would have seemed impossible. 2 Summary of the Portfolio This thesis examines Autobiographical memory (AM) in Alzheimer’s disease (AD). Specifically, Section A reviews the literature pertaining to the assessment of AM in AD in the context of test reliability, validity, and AM and longBterm memory (LTM) theory. The review suggests that theoretical understanding of how AMs are retrieved in AD, and how LTM in general is consolidated over time, has been limited by the methodological shortB comings of some measures which have not received the necessary scrutiny. Section B investigates the relationship between AM and the working memory (WM) and executive functions predicted to facilitate AM search and retrieval. It employs betweenB groups and correlational components with participants with earlyBstage AD and healthy controls matched for age, education, and intellectual ability. It uses an arguably more valid AM assessment task than has been used previously with AD samples in order to capture all aspects of semantic and episodic AM search and retrieval. The results indicate that weaker verbal fluency, but not WM, mediates a decline in episodic AM retrieval in AD independent of typical ageing effects. The clinical implications are discussed. Section C provides a critical appraisal of the research process by answering four specific questions. 3 Table of Contents Section A: Literature Review………………………………………………………………………………… 9 Abstract…………………………………………………………………………………………… 10 1. Introduction……………………………………………………………………………………… 11 1.1. Autobiographical memory 11 1.2. Alzheimer’s disease 13 1.3. Autobiographical memory and LongBTerm Memory in Alzheimer’s disease 13 1.4. Autobiographical memory assessment considerations 14 1.5. Aims of the review 15 2. Method……………………………………………………………………………………………. 16 2.1. Search methodology 16 2.2. Identification of assessment measures 16 3. Literature Review……………………………………………………………………………….. 17 3.1. Measures of autobiographical memory in Alzheimer’s disease 17 3.2. Relationships between autobiographical memory, executive function and 21 working memory in Alzheimer’s disease 3.3. Patterns of autobiographical memory recall across the lifespan in Alzheimer’s 25 disease 3.4. Further methodological issues 27 4. Discussion………………………………………………………………………………………... 28 4.1. What measures have been used to assess autobiographical memory in 28 Alzheimer’s disease and how reliable/valid are they? 4.2. Are the autobiographical memory tasks consistent with autobiographical 29 memory and longBterm memory theory? 4.3. What are the clinical implications for autobiographical memory assessment and 29 intervention? 4.4. Directions for future research 31 References………………………………………………………………………………………... 32 4 Section B: Empirical Paper…………………………………………………………………………………….. 41 Abstract……………………………………………………………………………………………... 42 1. Introduction………………………………………………………………………………………... 43 1.1. Working Memory 44 1.2. Executive Functions 45 1.3. Associations between autobiographical memory, working memory, and 46 executive function 1.4. Autobiographical memory, working memory and executive function in 47 Alzheimer’s disease 1.5. Rationale 48 1.6. Hypotheses 48 2. Method……………………………………………………………………………………………… 49 2.1. Design 49 2.2. Participants 50 2.3. Materials 51 2.4. Statistical analyses 56 2.5. Ethical considerations and procedure 58 3. Results………………………………………………………………………………………………. 59 3.1. Participant demographics 59 3.2. Potentially confounding variables 61 3.3. Hypothesis 1 61 3.4. Hypothesis 2 61 3.5. Hypothesis 3 64 3.6. Hypothesis 4 64 4. Discussion………………………………………………………………………………………….. 66 4.1. The role of working memory and verbal fluency in hierarchical search 67 4.2. The role of working memory and verbal fluency in episodic autobiographical 68 memory retrieval 4.3. Theoretical implications 69 5 4.4. Methodological considerations 70 4.5. Clinical implications 71 4.6. Future research 72 5. Conclusion………………………………………………………………………………………….. 72 References………………………………………………………………………………………….. 74 Section C: Critical Appraisal………………………………………………………………………………….. 84 1. What research skills have you learned and what research abilities have you developed 85 from undertaking this project and what do you think you need to learn further? 2. If you were able to do this project again, what would you do differently and why? 86 3. Clinically, as a consequence of doing this study, would you do anything differently and 88 why? 4. If you were to undertake further research in this area what would that research project 89 seek to answer and how would you go about doing it? References………………………………………………………………………………………….. 92 6 List of Tables Section A: Literature Review Table 1. Reliability and validity coefficients for autobiographical memory (AM) 20 tasks in healthy control (HC) and Alzheimer’s disease (AD) samples identified by the search strategy. Section B: Empirical Paper Table 1. Group means on demographic variables 59 Table 2. Pearson’s and Kendall’s correlation coefficients (two&tailed) between 62 potentially confounding variables and autobiographical memory (AM) measures. Table 3. Pearson’s and Kendall’s correlation coefficients between the VAF task, 63 and verbal fluency and working memory measures. Table 4. Regression coefficients for predictors of VAF4 episodic AM with bias& 65 corrected and accelerated 95% confidence intervals (BCa CIs). List of Figures Section A: Literature Review (cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:7) Hierarchical search in generative retrieval of autobiographical 12 memories according to Conway and PleydellBPearce (2000). Section B: Empirical Paper (cid:1)(cid:2)(cid:3)(cid:4)(cid:5)(cid:6)(cid:7)(cid:8)(cid:9)(cid:7) Mediation model for VAF4 episodic AM. 66 7 Section D: List of Appendices Appendix A Definitions of reliability and validity 94 Appendix B Systematic search procedure 96 Appendix C Table of identified studies 97 Appendix D Verbal Autobiographical Fluency scoring criteria 100 Appendix E Autobiographical Interview scoring criteria 101 Appendix F Tests of parametric assumptions of the data (betweenBgroups) 102 Appendix G Tests of parametric assumptions of the data (total sample) 142 Appendix H A priori power and sample size calculations 161 Appendix I NHS Research Ethics Committee approval letter 162 Appendix J Local NHS site R&D (anonymised) approval letters 163 Appendix K Example autobiographical memory response scoring 164 Appendix L ScatterBplots for working memory, verbal fluency, and 165 autobiographical memory tasks Appendix M Tests of assumptions for linear regression 173 Appendix N Participant information sheets 176 Appendix O Participant consent forms 185 Appendix P Verbal Autobiographical Fluency record form 187 Appendix Q Depression Anxiety and Stress Scale 21 item version (DASSB21) 191 Appendix R Neuropsychologia author guidelines 192 Appendix S NRES End of Study notification form 200 Appendix T Summary report to ethics committee and R&D departments 201 Appendix U Letter to ethics committee 203 8 Maxwell James Benjamin B.Sc. (Hons)., M.Sc. Major Research Project Section A: Literature Review Autobiographical memory in Alzheimer’s disease: A review of assessment methods and the evidence base. Word count: 5498 September 2013 SALOMONS CANTERBURY CHRIST CHURCH UNIVERSITY 9