Join lead author Barbara Stussman and co-author Dr. Brian Walitt of the
National Institutes of Health (NIH) in a conversation about these important findings in
#PEM and their impact on the next chapter of
#MECFS research.
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.