A brief, comprehensive measure of post-exertional malaise, 2025, Jason and Chee

[Mij]

I thought Table 4, effectiveness of pacing numbers interesting. I eliminated delayed PEM completely by pacing for years now.

This is entirely circular. It says that this questionnaire measures PEM because it measures what we say that PEM is.

They clearly didn't read my answers from previous questionnaires. I'm no longer spending my limited cognitive energy answering them.

 

[Hutan]

Next day soreness or fatigue after non-strenuous, everyday activities.
Mentally tired after the slightest effort.
Physically drained or sick after mild activity.
Dead, heavy feeling after starting to exercise.
Minimum exercise makes you physically tired.

Those items from Table 6 are almost a perfect list of things I want people to understand are not PEM. I think this tool is just going to confuse people.

 

[Simon M]

I thought the PEM duration work by Lenny Jason was incredibly useful. I'm not sure about the rest. To me, what we really need is an instrument that researchers can use to identify if people have PEM as it's the cardinal symptom of this disease.

I suspect that's not going to happen unless we do it, or initiate ithere.

This is what DecodeME used in its questionnaire, developed by people who live with the illness because there was nothing decent out there. I think it's pretty good, and more useful than the questionnaire discussed above to identify people who do have pem.

Symptoms after effort or activity

12. In the last 6 months, what happens to your symptoms after you do more physical or mental activity than usual (exceed your energy limit)? If you pace your energy, we want you to think about what would have happened if you didn't. Please only choose ONE answer.

 My symptoms (such as pain, fatigue or feeling out-of-sorts) get worse, or I get new symptoms, and this reduces how much I can do

 My symptoms either stay the same or improve (Skip to Question 14)

13. In the last 6 months, after you have done more physical or mental activity than usual (exceeded your energy limit), how long does the change in your symptoms usually last? If you pace your energy, we want you to think about what would have happened if you didn't. Please only choose ONE answer.

 The change in my symptoms lasts a long time, which can be more than 24 hours

 I bounce back straight away or my symptoms don't last very long given the effort I just made

I wonder if the final question, which uses my italics need more guidance. I’m concerned that exertion intolerance, seen in many illnesses after physical effort, would be captured by this. The Lenny Jason date suggested 12 hours would be a reasonable minimum, but we at least need to replicate that and There is always a danger with any threshold of losing milder cases.

 

[JemPD]

Minimum exercise makes you physically

So anyone who is normally sedentary. Is there any wonder that the deconditioning theory still rages on

Those items from Table 6 are almost a perfect list of things I want people to understand are not PEM. I think this tool is just going to confuse people.

Exactly.

Nearly everyone I know tells me they have brain fog now. Soon everyone will be telling me about their “PEM” when they feel knackered after a day’s work or a brisk walk.

 

[Kitty]

I wonder if the final question, which uses my italics need more guidance. I’m concerned that exertion intolerance, seen in many illnesses after physical effort, would be captured by this. The Lenny Jason date suggested 12 hours would be a reasonable minimum, but we at least need to replicate that and There is always a danger with any threshold of losing milder cases.

Yes, it's a good point. But even when my illness was at its mildest, I don't think I'd ever have ticked "I bounce straight back". I woke up feeling as if I had a virus or a hangover, but the worst of it only lasted around three hours.

I thought it was quite a clever phrase, as bouncing back is likely to be a distant memory in any severity of ME/CFS. If you asked people who're mild enough to be able to work how old they feel, I suspect quite a lot would go for the "80 – 90" option.

 

[Trish]

I doubt the idea that severity of ME/CFS correlates with duration of PEM.

Spoiler: My experience

Even when my ME/CFS was mild enough for me to teach 15 hours a week, plus at least equivalent prep time and caring for family, my crashes put me to bed for days, and I needed a week or two off work. The length and severity of my PEM is about the same now. I suspect the duration of PEM episodes depends more on the extent to which you push beyond your current PEM threshold. The difference for me is that now I'm severe physically, the amount of physical exertion that makes me crash is far less than it was when I was mild, and things like sitting up for too long and sensory stimuli contribute more noticably to whether I crash.

 

[Utsikt]

I thought the PEM duration work by Lenny Jason was incredibly useful. I'm not sure about the rest. To me, what we really need is an instrument that researchers can use to identify if people have PEM as it's the cardinal symptom of this disease.

I suspect that's not going to happen unless we do it, or initiate ithere.

This is what DecodeME used in its questionnaire, developed by people who live with the illness because there was nothing decent out there. I think it's pretty good, and more useful than the questionnaire discussed above to identify people who do have pem.

Symptoms after effort or activity

12. In the last 6 months, what happens to your symptoms after you do more physical or mental activity than usual (exceed your energy limit)? If you pace your energy, we want you to think about what would have happened if you didn't. Please only choose ONE answer.

 My symptoms (such as pain, fatigue or feeling out-of-sorts) get worse, or I get new symptoms, and this reduces how much I can do

 My symptoms either stay the same or improve (Skip to Question 14)

13. In the last 6 months, after you have done more physical or mental activity than usual (exceeded your energy limit), how long does the change in your symptoms usually last? If you pace your energy, we want you to think about what would have happened if you didn't. Please only choose ONE answer.

 The change in my symptoms lasts a long time, which can be more than 24 hours

 I bounce back straight away or my symptoms don't last very long given the effort I just made

I wonder if the final question, which uses my italics need more guidance. I’m concerned that exertion intolerance, seen in many illnesses after physical effort, would be captured by this. The Lenny Jason date suggested 12 hours would be a reasonable minimum, but we at least need to replicate that and There is always a danger with any threshold of losing milder cases.

I agree that this would probably also capture people that do not have PEM.

 

[Mij]

Table 6, symptoms of PEM

"Problems thinking"

Thinking is a mental process that allows you to learn, reason, and make decisions. I'm making decisions and reasoning just fine during PEM, it's just that I don't want to talk or interact with anyone atm.

 

[Mij]

Nearly everyone I know tells me they have brain fog now. Soon everyone will be telling me about their “PEM” when they feel knackered after a day’s work or a brisk walk.

Yes, like my dental hygienist who told me she has a few patients with CFS and Long Covid who are having difficulty getting diagnosed, and that she thinks she might have CFS. It was hard to explain to her while she's cleaning my teeth, but I did get a word or two in between polishing and fluoride treatment to explain a little. No I told her, it has an infectious onset (even though for some there is no obvious onset) but my appointment was over by then.

 

[Simon M]

I bounce back straight away or my symptoms don't last very long given the effort I just made

But even when my illness was at its mildest, I don't think I'd ever have ticked "I bounce straight back". I woke up feeling as if I had a virus or a hangover, but the worst of it only lasted around three hours.

I agree with the grades don't bounce back straight away". But I think someone who is struggling a bit with lots of illness illnesses, including depression, it might think the symptoms last a long time if they go on for three or four hours, which is the kind of timescale that Lenny Jason, found looking at MS for quite a lot of people. A small sub group of people with their S did have symptoms lasting more than 12 hours, and it's possible some of these did have PEM, but that's another issue.

 

[Mij]

I have never read or heard a pwMS describe delayed PEM that I experience. Why is that? It is a very abnormal/bizarre pathophysiological state that everyone with ME talks about after over exerting their energy limits.

Wouldn't physicians be aware of this state from pwMS by now?

 

[Andy]

Table 6, symptoms of PEM

"Problems thinking"

Thinking is a mental process that allows you to learn, reason, and make decisions. I'm making decisions and reasoning just fine during PEM, it's just that I don't want to talk or interact with anyone atm.

My decision making and reasoning are considerably worse during PEM.

 

[Kitty]

My decision making and reasoning are considerably worse during PEM.

Yup, I can't even form sentences. It's impossible even to hold a complete thought; it's all fragments, and even they keep slipping out of my grasp.

It feels as if the only way to get through a process of reasoning is to write it out in the sand with the end of a stick. I often can't finish the job before the tide starts coming in.

 

[Mij]

Ok, maybe we're coming from different angles between thinking and cognitive functions.

Thinking energy and cognition energy are used interchangeably, but cognition energy is a more formal term that refers to brain's capacity for mental work, including processing information, memory and attention. Thinking energy is a less formal way to describe the same ability to engage in tasks that involves cognition, like planning and decision making. Cognition energy has a more scientific backing which includes both physical and mental fatigue so I would prefer they use cognitive depletion.

For me, thinking means the same as 'brain fog', which I don't like.

 

[Utsikt]

I have never read or heard a pwMS describe delayed PEM that I experience. Why is that? It is a very abnormal/bizarre pathophysiological state that everyone with ME talks about after over exerting their energy limits.

Wouldn't physicians be aware of this state from pwMS by now?

Fatigue is often a very overlooked aspect of MS, so I’m not surprised if they have not picked up on PEM if it actually occurs.

Based on conversations with pwMS that are more severe, the person I spoke to understood instant onset PEM very well. They also understood delayed PEM, but I’m not sure if they had it or not - both of us were too foggy to get into the details.

 

[Mij]

@Utsikt There is unfortunately no ‘gold standard’ for fatigue, nor is there ever likely to be.

 

[Andy]

Ok, maybe we're coming from different angles between thinking and cognitive functions.

Thinking energy and cognition energy are used interchangeably, but cognition energy is a more formal term that refers to brain's capacity for mental work, including processing information, memory and attention. Thinking energy is a less formal way to describe the same ability to engage in tasks that involves cognition, like planning and decision making. Cognition energy has a more scientific backing which includes both physical and mental fatigue so I would prefer they use cognitive depletion.

For me, thinking means the same as 'brain fog', which I don't like.

I would be concerned about how many ordinary people, particularly if their ability to understand is affected by ME/CFS, would understand "cognitive depletion" as a description of their issues with decision making and reasoning? I share many of the concerns with this 'measure' of PEM, but I don't have an issue with "problems thinking" as a description.

And for me, I don't understand how you can equate thinking to be the same as brain fog. Or do you mean that, in your opinion, 'thinking' has the same lack of precision as a term as 'brain fog'? If so, that would be something quite different to what you put.

 

[Mij]

I recently had the opportunity to try to explain to my new GP what delayed PEM felt like for me. One question was if I had 'difficulty with decision making' in which I answered no, and went on to explain that I have an energy deficit/depletion that affects both my physically and cognition that causes my brain to shut down, and that I need to lie down and rest to recover for a few days. She understood that.

 

[Mij]

Brain fog, foggy brain difficulty thinking are all used interchangeably now. I don't feel that it describes my symptoms during PEM is all I'm saying.

 

[Mij]

Table 5 PEM Symptoms:

Five symptoms on that list don't apply to my experience with PEM or delayed PEM.

I have a sister who's been a flight attendant for decades and she would answer yes to almost all of them from jet lag, severe insomnia from a long flight and flying for years.

Another sister who has Hashimoto and obesity would answer yes to most of the symptoms too.

Do they have PEM? No. How is that list helping us? My Hashimoto sister says brain fog to describe everything from forgetfulness to 'can't think right now'.