EFFECTS OF AGING ON FUNCTIONS OF THE PREFRONTAL CORTEX *A thesis submitted in fulfilment of the requirements for the award of the degree DOCTOR of PHILOSOPHY from UNIVERSITY OF WOLLONGONG by GEOFFREY ARTHUR FOX, Bachelor of Arts DEPARTMENT OF PSYCHOLOGY 2004 Aging and Prefrontal Functions ii CERTIFICATION I, Geoffrey A. Fox, declare that this thesis, submitted in fulfilment of the requirements for the award of Doctor of Philosophy, in the Department of Psychology, University of Wollongong, is wholly my own work unless otherwise referenced or acknowledged. The document has not been submitted for qualifications at any other academic institution. Geoffrey A. Fox Date: Aging and Prefrontal Functions iii Table of Contents CERTIFICATION...............................................................................................................ii Table of Contents ...............................................................................................................iii CHAPTER ONE: GERIATRIC NEUROPSYCHOLOGY ...............................................1 1.1 The concept of aging. .............................................................................................1 1.2 Methodologies in research on age-related issues...................................................3 CHAPTER TWO - EVOLUTION, DEVELOPMENT, MATURATION AND INVOLUTION....................................................................................................................6 2.1 Evolution................................................................................................................6 2.2 Development. .........................................................................................................8 2.3 Maturity, Wisdom and Involution........................................................................10 2.4 The functions of the prefrontal cortex .................................................................12 CHAPTER THREE - THE NEUROPSYCHOLOGY OF THE PREFRONTAL CORTEX...........................................................................................................................14 3.1 Prefrontal lobe function .......................................................................................14 3.2 The concept of frontal system circuits .................................................................20 CHAPTER FOUR - MEMORY AND FRONTAL SYSTEM FUNCTION.....................24 4.1 The prefrontal cortex and working memory ........................................................24 4.2 A working definition for memory in this study ...................................................31 4.3 The role of the prefrontal cortex in compensation for dysfunction .....................31 CHAPTER FIVE: AGING AND NEUROINVOLUTION (PRIMARY AGING)..........34 5.1 Studies that have employed neuroimaging ..........................................................34 5.2 Studies that have employed EEG and ERP..........................................................36 5.3 Studies that have employed invasive technologies..............................................37 5.4 Studies that have employed pharmacological technologies.................................37 5.5 Studies that have employed neuropsychological instruments .............................39 5.6 Brief summary of other deficits in primary aging ...............................................41 5.7 Final Comment.....................................................................................................41 CHAPTER SIX: FORMS OF AGE-RELATED BRAIN PATHOLOGY (SECONDARY AGING).............................................................................................................................42 6.1 Cortical Dementias...............................................................................................42 6.1.1 Alzheimer’s Disease......................................................................................42 6.1.2 Creutzfeldt-Jakob Disease 6.2 Sub-cortical Dementias........................................................................................43 6.2.1 Progressive Supranuclear Palsy ....................................................................43 6.2.2 Parkinson’s Disease.......................................................................................43 6.3 Mixed Dementias .................................................................................................44 6.3.1 Focal Lobar Atrophy or Pick’s Disease ........................................................44 6.3.2 Vascular Dementia ........................................................................................45 6.3.3 Cortical Lewy Body Disease.........................................................................45 6.4 Treatable Causes of Dementia .............................................................................46 6.5 Conclusion ...........................................................................................................46 CHAPTER SEVEN: NEUROPSYCHOLOGICAL ASSESSMENT OF PREFRONTAL DYSFUNCTION...............................................................................................................47 7.1 Assessment of crystallised intelligence. ..............................................................50 Aging and Prefrontal Functions iv 7.1.1 Methods.........................................................................................................52 7.1.2 Results ...........................................................................................................52 7.1.3 Discussion .....................................................................................................52 7.2 Assessment of Fluid Intelligence.........................................................................53 7.2.1 Methods.........................................................................................................55 7.2.2 Results and Discussion..................................................................................56 7.3 The Block Counting Test .....................................................................................57 7.3.1 Methods........................................................................................................58 7.3.2 Results and Discussion.................................................................................58 7.3.3 Validation study ...........................................................................................59 7.3.3.1 Methods........................................................................................................59 7.3.3.2 Results ..........................................................................................................59 7.4 Assessment of Verbal Memory............................................................................59 7.4.1 Total Learning..............................................................................................60 7.4.1.1 Methods........................................................................................................60 7.4.1.2 Results ..........................................................................................................61 7.4.2 Validation Study: Total Learning.................................................................61 7.4.2.1 Method .........................................................................................................62 7.4.2.2 Results ..........................................................................................................63 7.4.3 Retrieval Efficiency......................................................................................64 7.4.3.1 Methods........................................................................................................64 7.4.3.2 Results ..........................................................................................................65 7.4.4 Band Rating..................................................................................................65 7.4.4.1 Methods........................................................................................................65 7.4.4.2 Results ..........................................................................................................67 7.4.5 Temporal Order ............................................................................................67 7.5 Measures of Non-verbal Memory........................................................................68 7.5.1 Visual Form Discrimination Test.................................................................68 7.5.1.1 Methods........................................................................................................68 7.5.1.2 Results ..........................................................................................................69 7.5.2 The Visual Form Memory Test.....................................................................70 7.5.2.1 Methods........................................................................................................70 7.5.2.2 Results ..........................................................................................................71 7.6 Measures of Performance Speed..........................................................................71 7.6.1 Sensori-Motor Speed: The Serial Reversals Test..........................................72 7.6.1.1 Methods........................................................................................................72 7.6.1.2 Results ..........................................................................................................73