Is PEM cumulative? - public thread

[JemPD]

This new thread has been split from this thread.

A Members Only thread also has relevant content.

My current thought is that we need to walk before we try to run and that means developing objective methods for documenting ME symptom patterns and PEM in particular. That ought to be possible with the use of actometers with the read out analysed with the sort of software that has been used for Parkinson's disease movement abnormalities. The key to testing a model of a clinical presentation is to have a very clear account of the clinical phenomenon one is trying to model. Only then can you see if the model's predictions really fit.

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.

 

[Hoopoe]

My current thought is that we need to walk before we try to run and that means developing objective methods for documenting ME symptom patterns and PEM in particular. That ought to be possible with the use of actometers with the read out analysed with the sort of software that has been used for Parkinson's disease movement abnormalities. The key to testing a model of a clinical presentation is to have a very clear account of the clinical phenomenon one is trying to model. Only then can you see if the model's predictions really fit.

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).

 

[Jonathan Edwards]

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).

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.

 

[Hoopoe]

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.

 

[Barry]

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.

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.

 

[Hoopoe]

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.

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.

 

[Jonathan Edwards]

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.

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.

 

[Sasha]

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

 

[Barry]

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

And brain activity.

 

[Trish]

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

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

 

[andypants]

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.

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.

 

[Jonathan Edwards]

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.

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.

 

[Sasha]

My current thought is that we need to walk before we try to run and that means developing objective methods for documenting ME symptom patterns and PEM in particular. That ought to be possible with the use of actometers with the read out analysed with the sort of software that has been used for Parkinson's disease movement abnormalities. The key to testing a model of a clinical presentation is to have a very clear account of the clinical phenomenon one is trying to model. Only then can you see if the model's predictions really fit.

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?

 

[Amw66]

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?

could we be a comparator arm as a quick route in?

 

[Hoopoe]

Relevant to GET and measurement of activity patterns:

In a previous study we demonstrated that while people with CFS had lower daily activity levels than control subjects, they were able to increase daily activity via a daily walking program. We reanalyzed our data to determine the time course of activity changes during the walking program. Daily activity assessed via an accelometer worn at the hip was divided into sleep, active, and walking periods. Over the first 4–10 days of walking the subjects with CFS were able to reach the prescribed activity goals each day. After this time, walking and total activity counts decreased. Sedentary controls subjects were able to maintain their daily walking and total activity goals throughout the 4 weeks. Unlike our previous interpretation of the data, we feel this new analysis suggests that CFS patients may develop exercise intolerance as demonstrated by reduced total activity after 4–10 days. The inability to sustain target activity levels, associated with pronounced worsening of symptomology, suggests the subjects with CFS had reached their activity limit.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1280928/

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

CFS patients had significantly lower daily activity counts than controls (162.5 ± 51.7 × 103 counts/day vs. 267.2 ± 79.5 × 103 counts/day) during a 2-week baseline period. At baseline, the CFS patients reported significantly (P < 0.01) higher fatigue and muscle pain intensity compared to controls but the groups did not differ in overall mood. CFS subjects increased their daily activity by 28 ± 19.7% over a 4 week period. Overall mood and muscle pain worsened in the CFS patients with increased activity.

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

 

[Jonathan Edwards]

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/

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.

 

[Jonathan Edwards]

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.

 

[Hoopoe]

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'.

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

 

[Hoopoe]

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.

 

[Jonathan Edwards]

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

Why did I miss that thread? - because it coincides exactly with my trip to Thailand.
So a large number of great minds think alike it seems.