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DePaul: Deconstructing post-exertional malaise: An exploratory factor analysis

Discussion in 'Latest ME/CFS Research' started by mango, Aug 25, 2016.

  1. mango

    mango Senior Member

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    Deconstructing post-exertional malaise: An exploratory factor analysis

    Stephanie L McManimen, Madison L Sunnquist, Leonard A Jason
    DePaul University, USA

    Abstract
    Post-exertional malaise is a cardinal symptom of myalgic encephalomyelitis and chronic fatigue syndrome. There are two differing focuses when defining post-exertional malaise: a generalized, full-body fatigue and a muscle-specific fatigue.

    This study aimed to discern whether post-exertional malaise is a unified construct or whether it is composed of two smaller constructs, muscle fatigue and generalized fatigue. An exploratory factor analysis was conducted on several symptoms that assess post-exertional malaise.

    The results suggest that post-exertional malaise is composed of two empirically different experiences, one for generalized fatigue and one for muscle-specific fatigue.

    Keywords: chronic fatigue syndrome, factor analysis, myalgic encephalomyelitis, operationalization, post-exertional malaise

    http://hpq.sagepub.com/content/early/2016/08/23/1359105316664139.abstract

    https://www.facebook.com/leonard.jason.12/posts/10208456959794536
     
    Last edited: Aug 25, 2016
  2. Invisible Woman

    Invisible Woman Senior Member

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    I appreciate the guys at DePaul are some of the good ones but .... AGAIN with the fatigue.....

    Fatigue is just a small part of PEM or PENE in my experience and is secondary to neuro symptoms and excruciating, abnormal muscle pain and weakness among other much nastier symptoms.
     
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  3. Valentijn

    Valentijn The Diabolic Logic

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  4. trishrhymes

    trishrhymes Senior Member

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    Is there any way of accessing the full article? And is it worth the effort anyway?
    I notice that the abstract uses the word 'fatigue' to describe both sorts of PEM. This rings alarm bells for me because it seems another instance of trivialising the reality of PEM, and hence of ME in the same way as renaming ME as CFS has done.
    For me I guess you could say there are two aspects to PEM.
    1. If I have overused one particular muscle group, eg legs from standing, or arms/shoulders from writing, I get greatly increased pain and weakness, and sometimes shaking or twitching in those muscles that can last for days.
    2. If I have done anything physical beyond my low threshold - whole body symptoms that can last days or weeks - flu-like symptoms - headache, nausea, dizziness, sore throat, overall weakness and pain in all muscles, inability to think straight or concentrate etc.
    The word 'fatigue' doesn't begin to describe these PEM symptoms.
    What do others think?
     
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  5. Snow Leopard

    Snow Leopard Hibernating

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    Sorry for the lost formatting, I hope this is clear. The main results:

    Also reported in tables was:
    Correlation and mean factor scores by demographic and functional status
    Percentage of patients meeting a 2–2 threshold for PEM symptoms

    But you'd have to read the actual paper to see those...

    edit:

    Demographic characteristics:
    The sample (N = 704) was predominantly female with just 10.3 percent male participants.
    Most participants were Caucasian (96.4%), and only 2 percent identified themselves as being of
    Latino or Hispanic origin. For marital status, 56.4 percent were married or living with a partner,
    2.6 percent were separated, 1.1 percent widowed, 13.4 percent divorced, and 26.5 percent never married.

    So looking at the above, it looks like a substantially biased (convenience) sample...
     
    Last edited: Aug 25, 2016
  6. trishrhymes

    trishrhymes Senior Member

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    Thanks everyone, looks like while I was busy writing my comment, others had done as I asked and made the same point! Great minds!
     
  7. Valentijn

    Valentijn The Diabolic Logic

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    They seem to be focusing on questionnaire items which best represent the experience of PEM:
    PEM items.jpg

    Interesting that the items from Jason's own questionnaire get the worst ratings :p Hopefully he'll be able to understand the descriptions of PEM some day.

    They're also looking at patient characteristics versus their two types of PEM responses, such as ability to work. Generally a positive piece, but as usual, completely the wrong focus on fatigue.
     
  8. Mij

    Mij Senior Member

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    If it was the questionnaire I tried to fill out a couple of years ago I'm not surprised, the way the questions were structured it was as though I was reading the SAME questions over and over again about how fatigue affects us. I was becoming dizzy and gave up. It gave me PEM.
     
  9. JohnCB

    JohnCB MEow

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    I felt that the whole introduction section was a very useful discussion of PEM/PENE. I am not going to comment here whether there was too much emphasis on fatigue; the word gets used so many different ways and seems to cover a range of concepts. However personally it is about pain and brain fog and symptom exacerbation as a whole.

    What they did was give a better overview of this subject than I recall seeing elsewhere. I certainly felt that I learnt a better understanding by taking the time to read this. I also found it interesting that the responses were different if asking about "exercise" or "daily activity". The discussion of what PEM was understood to be by the different authorities (Ramsay, Holmes, Goudsmit, etc.) was also useful for me.

    At this point I have not yet read the results. That is a joy for later, PEM allowing.
     
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  10. BruceInOz

    BruceInOz Senior Member

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    In the Results section, the paper says:

    Later they say they identified Factor I as a General factor and Factor II as a Muscle factor. I don't really understand how they did this, but it sounds like their numerical analysis of the responses grouped the questions into two distinct groups which they identified as General and Muscle. However, none of the questions ask only about mental fatigue - it is always lumped in with eg., "physical and mental" fatigue. Surely if they wanted to analyse factors like this they should have had questions that asked about mental fatigue only, in which case might they have discovered another factor. Since they took the questions from existing instruments, this may reflect a deficiency in those instruments,

    Just another example that seems to show that researchers don't get all the issues confronting us.
     
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  11. Dolphin

    Dolphin Senior Member

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  12. Dolphin

    Dolphin Senior Member

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    This is something I have noticed. When this pattern is off, I look out for comorbidities or alternatively alternative diagnoses.
     
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  13. Dolphin

    Dolphin Senior Member

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  14. Dolphin

    Dolphin Senior Member

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    Possibly useful in some form, as shows that not working is not simply a choice made by people who are no different in terms of impairment to people who are working.

     
  15. Dolphin

    Dolphin Senior Member

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    Reasonable exploration of possible interpretations of this finding, it seems to me:
    Contrast this with how many CBT school researchers discuss supports people get or could get
     
    Last edited: Aug 27, 2016
  16. Dolphin

    Dolphin Senior Member

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    Again, contrast this with how many CBT school researchers discuss supports people get or could get
     
    Last edited: Aug 27, 2016
  17. alex3619

    alex3619 Senior Member

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    I really wonder if this is a result of medical politics. Reviewers and editors may insist on "fatigue", or papers citing "fatigue" in the abstract might be more publishable.
     
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  18. alex3619

    alex3619 Senior Member

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    I was first told this by my CFS doc in 1993! He tracked his patients, and the happily married patients did much better. However he also said something not covered here - the patients who were unhappy with their marriage did worse than single patients.
     
  19. BruceInOz

    BruceInOz Senior Member

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    Yes, this is a generally positive sounding piece. But isn't it fascinating how in all of this sort of research the conclusions turn on the unsupported interpretation of the researchers. In this case we have, for example (and there are other similar examples)
    My bolding is the bit I'm calling an unsupported interpretation, which in this case I happen to agree is quite plausible. But they don't have any evidence for this, they've just identified a correlation. A BPS proponent writing the same paper with the same evidence before them would probably have written "This finding suggests patients should be encouraged to remain in employment as it should lead to an improvement of their symptoms". Surely conclusions or inferences that turn on researcher interpretation are just not science.
     
  20. alex3619

    alex3619 Senior Member

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    They can be if stated as an hypothesis. They are not if stated as fact. "Suggests" is the critical word here. Unfortunately many who want to believe in a particular interpretation of findings will take "suggests" and reject or accept it as fact based on their own preconceptions.
     

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