Is PEM cumulative? - public thread

Discussion in 'Post-Exertional malaise and fatigue' started by JemPD, Jan 27, 2019.

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  1. JemPD

    JemPD Senior Member (Voting Rights)

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    This new thread has been split from this thread.

    A Members Only thread also has relevant content.


    oh hallelujah. I've been thinking for years that how can any of it be of any proper use until we are really clear on what it is we're studying, especially re PEM. I think this is the only way to untangle from the quagmire of fatigue, chronic fatigue, ICF etc. So many of the researchers, even non BPS ones dont seem to fully understand the true clinical picture.
     
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  2. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    Between yesterday and today, something happened that had clear negative impact on me. I don't think it was exertion and am suspecting it was the ricotta I ate yesterday. I needed 3 hours more sleep than usual and am more symptomatic.

    This would register on an actometer mainly as having woken up unusually late (because my daily activity is already so limited). The actometer would need to be worn 24/7 for a while until this pattern became visible (and it might just reflect food intolerances).
     
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  3. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    Yes, I am assuming wearing the actometer 24/7 for maybe 3 months before it is likely to reveal useful patterns. The PACE authors thought this would be 'arduous' but my impression is that it would be OK. Parkinsonian patients have worn devices over extended periods to pick up the erratic 'on-off' episodes they get, which might be a bit akin to PEM episodes.
     
  4. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    Now that I think about it, with actometers there may be a floor effect when activity is already so low that episodes of further decline don't fully register.
     
    Last edited: Jan 27, 2019
  5. Barry

    Barry Senior Member (Voting Rights)

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    I imagine actometers only acquire data for physical activity that involves moving about. But even when laying dormant there is still an energy drain, simply by virtue of staying alive.
     
  6. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    Therefore, any study that attempts to document PEM should recruit patients with daily activity levels that are high enough for an eventual decline to clearly register.
     
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  7. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    Yes, I am not suggesting that attometers are likely to be so useful for measuring disability or quantity of activity - although this seems to be what most people sue them for. The idea is to use them to detect patterns of sequence in activity. The Parkinsonian patient has sudden shifts in activity with on-off. No doubt if you put an actometer on Andy Murray's right leg it would show a pattern of movement influenced by his hip pain. That is what I think needs to be documented in ME objectively.
     
  8. Sasha

    Sasha Senior Member (Voting Rights)

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    I'd love someone to invent an actometer that measures when you're horizontal. That would be hugely informative for PWME.
     
  9. Barry

    Barry Senior Member (Voting Rights)

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    And brain activity.
     
  10. Trish

    Trish Moderator Staff Member

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    My Fitbit is useless for measuring how long I sleep. It often registers lying quietly investment resting as sleep.
     
  11. andypants

    andypants Senior Member (Voting Rights)

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    I don’t think 3 months is enough. Many PwME will have cycles of doing just a tiny bit too much that can take months to build up to a crash. Others have a relapsing remitting form that flips every 3 or six months or so.
     
  12. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    I don't think that matters. There is no need for every example of a crash to be picked up in a pattern-finding study. Some people with Parkinson's do not have on-off episodes. As long as some common patterns crop up in some cases you can work with that. The idea is not so much to use it in individual cases as to document a common phenomenon to build theories around.
     
  13. Sasha

    Sasha Senior Member (Voting Rights)

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    This is an interesting idea. Is anybody doing anything like that? If not, can we get it proposed and/or put out to tender by one of the charities and/or the MRC/NIHR?
     
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  14. Amw66

    Amw66 Senior Member (Voting Rights)

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    could we be a comparator arm as a quick route in?
     
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  15. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    Relevant to GET and measurement of activity patterns:
    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1280928/

    In the original study, activity as measured by accelerometer increased, but symptoms worsened.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC555551/
     
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  16. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    Thanks @strategist,

    That is indeed a very useful set of data. It shows that this sort of extended monitoring is feasible and has been in use for at least fifteen years. One wonders why there is so little use of it recently.

    The only limitation I see here in relation to pattern tracking is that this is a formalised study, so the situation may not reflect the simple natural history of the illness, which is what I think we want to know first.

    Nevertheless, it seems to make a lot of sense of patients' stories.

    What I am beginning to get a sense of is that the problem in ME is not so much the activity limit at a point in time but that there is some sort of log jam in coping with a continuous stream of demand on 'exertion capacity'. As a crude analogy I think of a computer desktop. When you start off you can manage your documents easily. But if there is a problem filing away it becomes more and more difficult to find anything. If you take a break and do some filing then capacity returns. Another analogy might be a vacuum cleaner that works fine at first, but unless you keep cleaning the hair out of the brushes it soon becomes feeble until turned off and cleaned out.

    The analogies may not be that good but I wonder if the problem in ME is less activity capacity itself and more a block in systems that 'tidy away' afterwards so that the problem only appears later when you may be trying to do not very much but even that is blocked by a signalling log jam from before not being cleared away.
     
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  17. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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    The is actually an incredibly nice paper - short, dealing with one point and with one very clear data figure. It seems to say it all.
     
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  18. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    Take a look here https://www.s4me.info/threads/pem-cumulative-or-not.7524/
     
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  19. Hoopoe

    Hoopoe Senior Member (Voting Rights)

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    If I were to make a simulation of ME/CFs and PEM, then it would work a bit like this:

    Engaging in activities generates exertion points proportional to the intensity and duration of exertion.
    Sleep and rest removes exertion points proportional to the quality of the rest and sleep and duration.
    When exertion points reach a threshold, PEM is triggered.

    In a healthy person, PEM would never or rarely be triggered. ME/CFS would be an illness where there is some imbalance in this system so that exertion points rapidly accumulate, resulting in frequent and severe PEM until the person learns to pace better.

    These abstract exertion points could in reality be some waste product that accumulates or some resource that is depleted and is only slowly replenished.
     
    Last edited: Jan 30, 2019
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  20. Jonathan Edwards

    Jonathan Edwards Senior Member (Voting Rights)

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