The Fukuda criteria do not require post-exertional malaise, the essential feature of this illness, so they are NOT Defining Myalgic Encephalomyelitis

American Journal of Biochemistry and Biotechnology 6 (2): 120-135, 2010
ISSN 1553-3468
© 2010 Science Publications

1Leonard A. Jason, 1Meredyth Evans, 1Nicole Porter, 1Molly Brown,
1Abigail Brown, 1Jessica Hunnell, 1Valerie Anderson, 1Athena Lerch,
2Kenny De Meirleir and 3Fred Friedberg:

Corresponding Author: Leonard A. Jason, Department of Psychology, DePaul University, Center for Community Research,
Chicago, Il, 60614, USA Tel: 773-325-2018 Fax: 773-325-4923
120

The Development of a Revised Canadian Myalgic Encephalomyelitis
Chronic Fatigue Syndrome Case Definition
1Leonard A. Jason, 1Meredyth Evans, 1Nicole Porter, 1Molly Brown,
1Abigail Brown, 1Jessica Hunnell, 1Valerie Anderson, 1Athena Lerch,
2Kenny De Meirleir and 3Fred Friedberg
1Department of Psychology, DePaul University,
Center for Community Research, Chicago, Il, 60614, USA
2Department of Physical Education and Physical Therapy,
Vrije Universiteit Brussel, Belgium
3Department of Psychiatry and Behavioral Science,
State University of New York at Stony Brook, USA

Abstract: Problem statement: Several investigators have indicated that case definitions for Chronic
Fatigue Syndrome (CFS) are characterized by vaguely worded criteria that lack operational definitions
and guidelines. The most widely used CFS case definition is the Fukuda et al. criteria, which uses
polythetic criteria (i.e., patients are only required to have four out of a possible eight symptoms).

Yet two of these eight symptoms (post-exertional malaise and memory/concentration problems) are an
essential feature of this illness and the Fukuda et al. criteria do not require that these symptoms be
present among all patients.

Significant methodological problems could occur if investigators in
different settings recruit samples with different percentages of these core symptoms. In contrast, the
Canadian clinical case definition does require specific ME/CFS symptoms such as post-exertional
malaise and memory/concentration problems. The provision of operationally explicit, objective criteria
on specific key symptoms might reduce criterion variance as a source of unreliability. In addition, the
use of structured interview schedules will ensure that symptoms are assessed in a consistent way
across settings.

Conclusion/Recommendations: In this article, we specified explicit rules for
determining whether critical symptoms meet ME/CFS criteria using a revised Canadian case definition
and a questionnaire has been developed to assess core symptoms. It is hoped that these developments
will lead to increased reliability of this revised Canadian case definition as well as more frequent use
of these criteria by investigators.

Key words: Myalgic encephalomyelitis, chronic fatigue syndrome, chronic fatigue, post-exertional
malaise, Illness

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See also: The main characteristic of ME is an abnormally delayed muscle recovery after doing trivial things, if you don't have that, you don't have ME