AUTHOR=Twisk Frank N.

TITLE=The status of and future research into Myalgic Encephalomyelitis and Chronic Fatigue Syndrome: the need of accurate diagnosis, objective assessment, and acknowledging biological and clinical subgroups

JOURNAL=Frontiers in Physiology

VOLUME=Volume 5 - 2014

YEAR=2014

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2014.00109

DOI=10.3389/fphys.2014.00109

ISSN=1664-042X

ABSTRACT=Myalgic Encephalomyelitis (ME) was identified as a new clinical entity in 1959 and has been acknowledged as a disease of the central nervous system/neurological disease by the World Health Organisation since 1969. Cognitive impairment, (muscle) weakness, circulatory disturbances, marked variability of symptoms, and, above all, post-exertional malaise: a long-lasting increase of symptoms after minor exertion, are distinctive symptoms of ME.<br/>Chronic Fatigue Syndrome (CFS) was introduced in 1988 and was redefined into clinically evaluated, unexplained (persistent or relapsing) chronic fatigue, accompanied by at least four out of a list of eight symptoms, e.g. headaches and unrefreshing sleep, in 1994.<br/>Although the labels are used interchangeably, ME and CFS define distinct diagnostic entities. Post-exertional malaise and cognitive deficits e.g. are not mandatory for the diagnosis CFS, while obligatory for the diagnosis ME. “Fatigue” is not obligatory for the diagnosis ME.<br/>Since fatigue and other symptoms are subjective and ambiguous, research has been hampered. Despite this and other methodological issues, research has observed specific abnormalities in ME/CFS repetitively, e.g. immunological abnormalities, oxidative and nitrosative