The Nature of Memory Impairment in Chronic Fatigue Syndrome

Objective: Examine whether memory impairment in chronic fatigue syndrome (CFS) is due to deficits in acquisition, storage, or retrieval. Study Design: Prospective, between-groups design. Participants: Twenty-nine CFS participants without psychiatric comorbidity (CFS-noPsych) and 22 participants with an Axis I psychiatric diagnosis since CFS onset. Two control groups: 30 healthy persons and 19 participants with rheumatoid arthritis. Main Outcome Measures: After being equated for initial learning, recall and recognition were assessed after 30- and 90-min delays. Results: Both CFS groups required more trials to learn the word list than did healthy controls. The CFS-noPsych group performed significantly below healthy controls on recall but not on recognition. Learning/acquisition correlated with measures of complex information processing and not with depressive symptomatology or fatigue. Conclusions: Impaired verbal learning and memory in CFS is primarily a result of deficient acquisition.