Cognitive functioning in chronic fatigue syndrome

................................................................................................................... 99 Introduction ............................................................................................................ 100 Method ................................................................................................................... 104 Participants ......................................................................................................... 104 Measures ............................................................................................................ 106 Procedure ........................................................................................................... 108 Results .................................................................................................................... 108 Participant characteristics .................................................................................. 108 Validity Indicator Profile performance .............................................................. 110 Self-reported effort & energy levels .................................................................. 111 Compensation .................................................................................................... 112 Discussion .............................................................................................................. 113 Conclusion ............................................................................................................. 116 References .............................................................................................................. 117 Chapter 5: Study 2 (Part 2) ........................................................................................ 123 Cognitive deficits in Chronic Fatigue Syndrome and their relationship to psychological status, symptomatology and everyday functioning. ........................... 123 Preamble ................................................................................................................ 124 Abstract .................................................................................................................. 126 Introduction ............................................................................................................ 127 Psychological status ........................................................................................... 128 CFS symptoms and onset ................................................................................... 129 Everyday functioning ......................................................................................... 130 Effort .................................................................................................................. 130 Study aims .......................................................................................................... 131 Method ................................................................................................................... 132 Participants ......................................................................................................... 132 Measures ............................................................................................................ 133 Procedure ........................................................................................................... 136 Analysis .............................................................................................................. 136 Results .................................................................................................................... 137 CFS symptoms ................................................................................................... 138 Everyday functioning. ........................................................................................ 140 Psychological status. .......................................................................................... 141 Cognitive performance ....................................................................................... 142 Relationship between cognition, psychological status, symptoms and functioning in CFS ................................................................................................................ 142 Discussion .............................................................................................................. 145 Conclusion ............................................................................................................. 152 References .............................................................................................................. 153 Chapter 6: Study 2 (Part 3) ........................................................................................ 161 Cognitive functioning in people with Chronic Fatigue Syndrome: A comparison between subjective and objective measures ............................................................... 161 Preamble ................................................................................................................ 162 Abstract .................................................................................................................. 164 Introduction ............................................................................................................ 165 Method ................................................................................................................... 169 Participants ......................................................................................................... 169 Measures ............................................................................................................ 170 Procedure ........................................................................................................... 174 Analysis .............................................................................................................. 174 Results .................................................................................................................... 175 Cognitive tests .................................................................................................... 176 Self-report measures .......................................................................................... 176 Relationship between objective and subjective measures of cognitive performance ....................................................................................................... 178 Self-evaluations of performance, cognitive effort, mental fatigue, and recovery time .................................................................................................................... 180 Impact of test order on cognitive performance .................................................. 182 Fatigue, sleep, depression and anxiety. .............................................................. 182 Discussion .............................................................................................................. 185 Conclusion ............................................................................................................. 189 References .............................................................................................................. 190 Chapter 7: Discussion ................................................................................................ 197 Summary of Findings ............................................................................................. 197 Cognitive deficits in CFS. .................................................................................. 197 Potential causes, correlates and consequences of cognitive impairments. ........ 200 Self-reported cognitive problems and performance. .......................................... 202 Implications of Findings and Recommendations for Future Research .................. 204 Key strengths and limitations ................................................................................. 209 Study 1: Meta-analytic review. .......................................................................... 209 Study 2: Empirical study of cognitive deficits. .................................................. 211 Final Conclusions ................................................................................................... 214 References .................................................................................................................. 215 Appendix A: Journal format of paper from Study 1 “Cognitive functioning in chronic fatigue syndrome: a meta-analysis” ........................................................................... 257 Appendix B: Journal format of paper from Study 2 (Part 1) “Test effort in persons with Chronic Fatigue Syndrome when assessed using the Validity Indicator Profile” .................................................................................................................................... 275 Appendix C: Journal format of paper from Study 2 (Part 2) “Cognitive deficits in Chronic Fatigue Syndrome and their relationship to psychological status, symptomatology and everyday functioning” ............................................................. 287 Appendix D: Journal format of paper from Study 2 (Part 3) “Cognitive functioning in people with Chronic Fatigue Syndrome: A comparison between subjective and objective measures” ................................................................................................... 303