Neuropsychological and psychosocial aspects of chronic fatigue syndrome

Abstract

This Thesis reports a full scale study of cognition and mood in Chronic Fatigue Syndrome (CFS) longitudinally during recovery. Previous studies fail to cover the scope of this study and/or fail to define adequately the syndrome for subject selection. 47 CFS patients were compared with 41 normal and 26 Crohns/colitis controls in a longitudinal study of cognitive performance and depression/anxiety scores. CFS patients performed significantly worse than controls on many of the cognitive tests at first testing. Small but significant differences between CFS and normal controls were found on memory tests (Logical Memory, Word Recognition and, more significantly, Rey Complex Figure) but Crohns/colitis patients scored similarly to CFS, suggesting that this might relate to a general problem such as attention. Much larger and more significant differences between CFS and both control groups were found on tests involving a psychornotor component (e. g. Reaction Time, Finger Tapping and Digit Symbol). CFS patients' performance improved over time (above practise) on word recognition, Stroop (colours), Reaction Time (Movement) and Digit Symbol. CFS patients were significantly more depressed/anxious than the control groups and scored higher on Middlesex Health Questionnaire (Psychiatric). Depression/anxiety did not diminish significantly by second testing. Differences on depression scores accounted for some of the differences in cognitive test performance, in particular Word Fluency and Stroop; however, significant differences remained after ANCOVA removed depression: significant differences remained on Logical Memory, Word Recognition, Digit Symbol, Finger Tapping and Reaction Time. It was concluded that CFS patients were slowed on psychornotor tasks and that this was only partly accountable by depression as suggested by depressed score. CFS patients performed slightly worse on some other tests possibly dependant upon the task demand. Digit Symbol, Reaction Time, and Finger Tapping seemed to be most sensitive to CFS. Brain damage was not necessarily indicated by the results: differences in psychornotor performance could be caused by difficulties in the transmission of instructions to the muscle or slowness in the nerves and muscles themselves. CFS patients' performance significantly improved on a number of tests over time, and did not significantly deteriorate on any test; therefore, the trend of CFS patients' test performance overall was to get better not worse over time.