A personal letter to the NIH team researching ME/CFS about their PEM study, 2020

It's really bugging me that Solve are describing this paper as 'important' and identifying differences 'for the first time'. Feels like eminence based medicine.

I tried asking them on Twitter whether I can ask a question for them to answer in the webinar, but have had no response. Maybe they are still thinking about it, or maybe they don't want to allow questions. Do Solve Webinars include a question time?
And if I do send them a question, what should it be?

I tried to write an article for possible publication, maybe even in the same journal, but I've run out of steam. Someone who is very good at writing about ME offered to help, but we didn't immediately agree on how to tackle it, and I ran out of energy. I've had several goes at drafting something and got stuck.

I really think this is important that the definition of PEM should be clarified, so people are not talking at cross purposes with some assuming it means all increases in symptoms following any activity, and others thinking it refers only to the 'crash' when the energy envelope is exceeded, and the thing we all try to avoid by pacing.

I think until that is clarified in definitions, diagnostic criteria and research, we will go on getting this sort of poor quality stuff that manages to both ask the wrong questions and analyse the results in ways that lose a lot of the valuable information supplied by patients, and end up with nonsensical conclusions.

I wondered about doing a study consisting of a questionnaire to be answered separately by clinicians, researchers, leaders of patient organisations, and patients on whether they think PEM includes both fatiguability and crashes, or just crashes and fatiguability should be described separately. And whether they think there is a continuum or a cliff edge between the two.

 

Ah, yes, I forgot it's the weekend!

 

Now that I've seen the NICE guideline with its clear definions of fatiguability and PEM, I think I might ask something about that - how they define PEM and whether they think it's important in researching PEM that the make it clear to participants which of these they are asking about.

And a follow up question asking whether they recognise that in conflating the two in their questions they muddied the waters.


I'd also like to ask them why they think trying to describe PEM on the basis of lists of symptoms is helpful given that when patients experience PEM, they experience exacerbation of all their symptoms, so all they are doing is going around in circles arriving back at the diagnostic criteria for ME.

And I'd like to ask them whether they recognise that by including fatiguablity in their questions they emphasised the immediate cognitive and muscle effects when actually PEM exacerbates all symptoms.

And
And
And...
Hmm.

 

Here's what I'm about to send to Solve. Done in a bit of a rush as I've been up to my eyes in NICE guideline discussions. Too late for suggested amendments, I'm sending it now!




To Solve ME

re Seminar with Dr Stussman and Dr Wallit, Wednesday, December 2.

Please can you ask this question of Drs Stussman and Wallit on my behalf, for their seminar on Wednesday December 2, about their recently published paper on PEM in ME/CFS.

I am sorry I'm rather late submitting it. I have been very busy discussing with Science for ME forum members the newly released draft UK NICE guideline for ME/CFS.

I am sorry this is such a long question. I hope you will be able to put it to Drs Stussman and Walitt. Please feel free to send it to them in advance. They may recognise my name as the author of a rather long letter expressing my concerns about their paper. I do hope they will take my question in the spirit in which is intended - to forward progress in getting clarity in the definition of PEM, and consequently in the accurate diagnosis and research on ME/CFS.

Question:

I would like to ask Dr Stussman and Dr Walitt if they would clarify the definition of PEM they used in their research. The reason I ask is that there appear to be two different versions of PEM, leading to confusion among patients and researchers.

Definition 1

As the new draft UK NICE ME/CFS guideline [1] uses the term PEM, it applies specifically to the, usually delayed, effect of exceeding the patient's energy threshold, or envelope, making the patient much sicker and less functional for days or longer. Many patients, researchers and patient organisations use the term this way, with pacing recommended as a management strategy to try to reduce the frequency of episodes of PEM. ​

Definition 2

The second definition, which appears to have been used in Stussman and Walitt's paper, refers to all effects of any exertion. It conflates the phenomenon described in the first definition with the build up of symptoms resulting from all daily activity, defined separately by NICE, among others, as 'fatiguability'. Unlike PEM, fatiguablity is unavoidable, and the symptoms that build up during and immediately after activity are likely to be particularly the directly energy related ones such as muscle pain and weakness, congitive worsening and exhaustion.​

By conflating daily fatiguablity with intermittent PEM into a single phenomenon in their questions to the focus groups, the study under discussion produced a set of core symptoms for PEM that, while they are part of PEM, are much more accurately descriptive of fatiguablity, namely muscle and cognitive symptoms and exhaustion. They leave out the very significant factors of 'malaise' and reduction in function that lasts for days or longer.

I have been informed by a professor of medicine that 'malaise', in medical terminology, means 'feeling terrible', 'not just a bit off colour, terrible. It is what you get with mono, typhoid vaccination, flu, septicaemia, acute dermatomyositis. It is BAD'.

The omission of 'malaise' from the core symptoms of PEM, leads to the erroneous deduction that PEM in ME/CFS parallels the experience of post exertional fatigue in other illnesses. I wonder, can Drs Wallit and Stussman name any chronic illness where a small increase in energy expenditure outside the energy envelope one day leads to days in bed feeling like you have run a marathon, have a hangover, and have a bad dose of influenza?

Finally if they would like to address any of the other issues I raised in my letter, I would be very interested to hear their thoughts.

References:
[1] The draft NICE ME/CFS guideline published earlier this month
https://www.nice.org.uk/guidance/gid-ng10091/documents/draft-guideline

[2] My letter to the research team led by Dr Walitt and Dr Stussman.
https://www.s4me.info/threads/a-per...hing-me-cfs-about-their-pem-study-2020.17148/
And their reply:
https://www.s4me.info/threads/a-per...about-their-pem-study-2020.17148/#post-294139

With thanks and best wishes,

Trish Davis. UK ME/CFS patient and carer.

 

Thanks @alktipping. Much appreciated. As a demonstration of the cognitive fatiguability induced by drafting that short email, it took me over an hour to draft, and I am now barely able to type this short post, and am having to focus my eyes and brain slowly on each word and correct at least half of them!

Time to stop!

 

When I was still working when my ME was mild, I thought of it as like a cliff edge, or falling off a high wall or tightrope. I would walk carefully along my tightrope, and every now and again, I'd try to go too fast, or not take enough time to rest and regain my balance when I wobbled, and fall off and need a week or 2 off work. I think we need to convey that going into PEM is not just a gentle downward slope, it's like falling off something very high into a pit.