Article Index

Case definitions

Leonard Jason (Chicago, USA) led this discussion and compared the various case definitons and their evolution over the past 25 years. The main variation in the definitions is the number of symptoms required for making a diagnosis. Case definitions that do not require the cardinal symptoms may not accurately identify the illness. However defintions requiring larger numbers of symptoms may include more psychiatric morbidity. Current consensus based definitions may lack construct validity, resulting in inaccurate diagnosis of CFS/ME.

A study to determine whether immunological, physical and social functioning varies in CFS/ME was presented by Sharni Hardcastle, (Gold Coast, Australia). Findings suggest that the ICC case definition [Canadian] identifies a group within the 1994 Fukuda defined patients with more severe impairment to their physical and social functioning. The ICC may also be more effective at identifying differences in the immune system found in CFS/ME. The presence of immune abnormalities combined with clear clinical measures could potentially serve as an important diagnostic tool in this illness.

Leonard Jason (Chicago, USA) then looked at diagnostic and criterion issues. Studies included looking at the prevalence of chronic fatigue in the general population. In order to progress the search for biologic markers and effective treatments, essential features of the illness might be empirically identified, so that individuals included in samples have the same underlying illness. Advanced statistical techniques, such as data mining are promising methods for identifying these features.