Peter T
Senior Member (Voting Rights)
Welcome @Janet Stone, your participation here is most welcome. Jason et al’s work is very important, and I think most here recognise the value of having an established group of subjects studied from before the onset of their post viral journey. It is something that should also have been done [more widely] early on in the Covid pandemic, as many of us called for.
It may be that people meeting a number of diagnostic criteria have a greater certainty of diagnosis, given ME/CFS is currently defined only by symptoms and the fact that there has been a disconcertingly high percentage of misdiagnosis, potentially up to 40% in some previous studies. So it may be useful to have some indicator of diagnostic confidence, or even a way of distinguishing those that have core symptoms and those that may previously have been included in older CFS diagnoses, who predominantly display chronic fatigue but do not meet more recent definitions of ME/CFS.
There even may be value in knowing more about people with chronic fatigue but not ME/CFS as we now understand it, who potentially now get totally abandoned by serious researchers. Certainly this is relevant to understanding the range of post viral conditions. But it is important that this is clarified from the outset and not confounded with the idea of severity, which most clinical guidelines and most other researchers relate to degree of impaired functioning.
It may be that the core ME/CFS group is on average more impaired than the looser chronic fatigue group, but this may only be a correlation found in larger groupings but is not a necessary or causal relationship. Since my onset associated with an acute EBV infection (glandular fever) I have met the all various diagnostic criteria that would place me in the Jason et al ‘severe’ category but in terms impaired functioning over thirty years I have at various times fluctuated between mild, moderate, severe and very severe as defined by such as the NICE guidelines. So there is the confusion that at times concurrently I have been both mild and ‘severe’, both moderate and ‘severe’ and both ‘severe’ and very severe. This is undoubtedly an unnecessary source of confusion that would most easily be avoided by Jason et al’s ‘severe’ grouping being relabelled.
Similarly, I would argue that there is a confusion in labelling between PEM as defined by such as the DePaul questionnaire and what patients now understand by PEM. Such as the DePaul questionnaire focuses on fatiguability. Many if not most researches who have tried to create an operationalised definition of PEM focus primarily on exertion having a more rapid or more dramatic development of fatigue. However this may be unhelpful as such increased fatiguability is present in many other conditions from flue, to stroke to cancer. Such is like say headache, a non specific feature, and to define PEM in this way enables people like Live Landmark and others to claim ME/CFS does not exist as a distinct entity as PEM so defined does not distinguish it from many other conditions.
More recent definitions of PEM explain it not as an exaggeration of the normal fatigue process but as an aberrant response to exertion including a feeling of malaise, reemergence of old symptoms, emergence of new symptoms, counter intuitive changes over time, etc. See our PEM fact sheet for more discussion. This is includes rapid fatiguability but is not just that, so such as the DePaul questionnaire results may correlate to more recent understandings of PEM, but does not have the discriminatory power needed for research purposes. I acknowledge that more work needs to be done defining PEM to create a useful tool for research purposes, but that should not be impossible.
[ sorry continued editing after posting. Mainly corrected typos but did also add the reference to Covid in the first paragraph.]
It may be that people meeting a number of diagnostic criteria have a greater certainty of diagnosis, given ME/CFS is currently defined only by symptoms and the fact that there has been a disconcertingly high percentage of misdiagnosis, potentially up to 40% in some previous studies. So it may be useful to have some indicator of diagnostic confidence, or even a way of distinguishing those that have core symptoms and those that may previously have been included in older CFS diagnoses, who predominantly display chronic fatigue but do not meet more recent definitions of ME/CFS.
There even may be value in knowing more about people with chronic fatigue but not ME/CFS as we now understand it, who potentially now get totally abandoned by serious researchers. Certainly this is relevant to understanding the range of post viral conditions. But it is important that this is clarified from the outset and not confounded with the idea of severity, which most clinical guidelines and most other researchers relate to degree of impaired functioning.
It may be that the core ME/CFS group is on average more impaired than the looser chronic fatigue group, but this may only be a correlation found in larger groupings but is not a necessary or causal relationship. Since my onset associated with an acute EBV infection (glandular fever) I have met the all various diagnostic criteria that would place me in the Jason et al ‘severe’ category but in terms impaired functioning over thirty years I have at various times fluctuated between mild, moderate, severe and very severe as defined by such as the NICE guidelines. So there is the confusion that at times concurrently I have been both mild and ‘severe’, both moderate and ‘severe’ and both ‘severe’ and very severe. This is undoubtedly an unnecessary source of confusion that would most easily be avoided by Jason et al’s ‘severe’ grouping being relabelled.
Similarly, I would argue that there is a confusion in labelling between PEM as defined by such as the DePaul questionnaire and what patients now understand by PEM. Such as the DePaul questionnaire focuses on fatiguability. Many if not most researches who have tried to create an operationalised definition of PEM focus primarily on exertion having a more rapid or more dramatic development of fatigue. However this may be unhelpful as such increased fatiguability is present in many other conditions from flue, to stroke to cancer. Such is like say headache, a non specific feature, and to define PEM in this way enables people like Live Landmark and others to claim ME/CFS does not exist as a distinct entity as PEM so defined does not distinguish it from many other conditions.
More recent definitions of PEM explain it not as an exaggeration of the normal fatigue process but as an aberrant response to exertion including a feeling of malaise, reemergence of old symptoms, emergence of new symptoms, counter intuitive changes over time, etc. See our PEM fact sheet for more discussion. This is includes rapid fatiguability but is not just that, so such as the DePaul questionnaire results may correlate to more recent understandings of PEM, but does not have the discriminatory power needed for research purposes. I acknowledge that more work needs to be done defining PEM to create a useful tool for research purposes, but that should not be impossible.
[ sorry continued editing after posting. Mainly corrected typos but did also add the reference to Covid in the first paragraph.]
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