Memory impairments in chronic fatigue syndrome patients.

Background: Chronic Fatigue Syndrome (CFS) patients often report memory problems. Prior research has produced conflicting results on this topic. Episodic memory impairments appear to be robust, but tasks assessing other aspects of memory (e.g., working and semantic memory) show slower speed but no decrease in accuracy. This study examined whether the memory problems of CFS patients reflect slower responses. Methods: CFS patients were recruited from a specialist clinic. Sixty-seven patients carried out tasks measuring immediate recall, delayed recognition memory, logical reasoning and semantic processing. The control group were 126 healthy volunteers recruited from the general population. Results: The CFS patients recalled fewer words and had poorer delayed recognition. The other tasks showed slower speed but no effect on accuracy. Conclusions: CFS patients have poorer immediate recall and delayed recognition memory. The delayed recognition memory probably reflected the poorer immediate recall. Slower responding was present in three of the tasks, and it is possible that this also accounted for the reduced immediate recall