Why are the majority of pwME rarely mentioned?

[Sly Saint]

I know the issue of severity is sensitive and don't want to get into a 'my ME is worse than yours' kind of debate.

But I have only recently begun to notice that most literature (including from the charities) although noting the 25% severely affected, and emphasising the debilitating nature of the disease generally (as they should), the vast majority of ME sufferers who fall into the category between 'mild' and severe rarely get mentioned.

People in the general public and (medical health professionals) might know someone who has ME and is still working, and some may be aware of those who are long-term severely affected and bedbound, but how many are aware that the majority of pwME fall somewhere between these two scenarios?

I have been trying to find some statistics and the only ones I have found so far are these:

"Around 25 per cent of people with ME/CFS will have a mild form and be able to get to school or work either part-time or fulltime, while reducing other activities.

About 50 per cent will have a moderate to severe form of ME/CFS and not be able to get to school or work.

Another 25 per cent will experience severe ME/CFS and have to stay at home or in bed."

https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/chronic-fatigue-syndrome-cfs
https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/chronic-fatigue-syndrome-cfs
Might it not be a good idea to get over the additional message that the majority of people with ME struggle just to maintain activities of daily living

(https://en.wikipedia.org/wiki/Activities_of_daily_living )

and that only 25% of pwME are able to continue (albeit with difficulty) with regular additional activities?

This appears to get lost in any media coverage, and certainly is not something that the benefits assessors appear to be aware of.

(if anyone can find any other stats on this issue please post).

 

[Trish]

But I have only recently begun to notice that most literature (including from the charities) although noting the 25% severely affected, and emphasising the debilitating nature of the disease generally (as they should), the vast majority of ME sufferers who fall into the category between 'mild' and severe rarely get mentioned.

Around 25 per cent of people with ME/CFS will have a mild form and be able to get to school or work either part-time or fulltime, while reducing other activities.
.....
.....

I think you make a good point.

I would not characterise it as 'have a mild form of ME'. From my experience I have had the same ME for 29 years but it has varied from mild through moderate to moderately severe. So far I have avoided the very severe state but it could happen. I think one thing that is often not understood or made clear in charity information is that you can slip from one level to another at any time, they are not different diseases.

 

[Cinders66]

I think the work statistic is worth getting out more. I think that the chronic fatigue label puts in people’s mind the idea of being tired but functioning, something you live with and therefore it’s our unfortunate job whilst that still prevails to emphasise the debilitating nature, 75% unable to work is very high, being unable to work as an adult in prime age is major. Also Severe ME is treated as the exception yet the same percent are mild which has much more focus. I also think the language fluctuating condition (dictionary on Alexa says means having unpredictable ups and downs) , suggests we all, have quite marked random ups and downs regularly, whereas I think many people live in quite a narrow margin, long term, with ups and downs related to activity.

I think firstly we have to move away from the chronic fatigue stuff both as short hand and in literature to mean CFS/ME ASAP.

I’d be interested in ME debility stats versus FM. Reading through some of the FM Debate, especially the bit where the well known brexit MP said she had it but sort of in a yes it’s tough but I plod on and it could be worse way (which might just mean she had a mild form rather than FM is less debilitating). What portion of FM diagnosed people can’t work.

As ever another gift from the BPs school is that “no matter the severity most can get a lot better” myth. Which they might not put plainly like that but that is the impression. So in some ways us not being in work to the public just fits in with an extended version of them having time off for flu, no big deal. It’s only if debility and chronicity and being sick not deconditioned is conveyed that sympathy will be won.

 

[DokaGirl]

I agree @Trish, pwME can slip from mild to moderate or severe. To pigeon hole pwME at a certain level, and assume this will never change is narrow minded, and uneducated.

PwMS can go from mild to moderate to severe.

Forcing pwME to participate in GET can potentially cause ME to worsen.

Deterioration can also occur for no apparent reason.

ME and MS are both spectrum diseases. When you think about it, so are many diseases, and maybe all diseases; some people can have a mild flu, others may die from it, even young, strong, healthy people can die from the flu.

 

[Snowdrop]

I'd like to unhitch the idea that anything we do has an effect on the progression. This of course should not stop us from trying to understand our own situation and see what works for us in terms of not having worse days. But I'm talking long term. There's making things worse by what we do in the short term and there's possibly (we don't know) not a thing to be done long term to stop progression.

And it really is clear that, as Sly points out a huge number of people with ME are completely overlooked because they are neither easy to describe as struggling to work or as truly sick unable to do activities of daily life.

A lot more description needs to be provided for people to begin to understand. The anthropology again. When I was still functioning in a way that looked normal I was struggling in so many ways that were invisible to others.

I don't have the energy for it but I would encourage anyone who can to create a longish post on the story of their getting ill as Trish has done.

We could have an anthology of ME.

 

[Cinders66]

I

I'd like to unhitch the idea that anything we do has an effect on the progression. This of course should not stop us from trying to understand our own situation and see what works for us in terms of not having worse days. But I'm talking long term. There's making things worse by what we do in the short term and there's possibly (we don't know) not a thing to be done long term to stop progression.

And it really is clear that, as Sly points out a huge number of people with ME are completely overlooked because they are neither easy to describe as struggling to work or as truly sick unable to do activities of daily life.

A lot more description needs to be provided for people to begin to understand. The anthropology again. When I was still functioning in a way that looked normal I was struggling in so many ways that were invisible to others.

I don't have the energy for it but I would encourage anyone who can to create a longish post on the story of their getting ill as Trish has done.

We could have an anthology of ME.

i respectfully disagree. I have slid down from mild to 100% bedridden over years, starting from many years ago when ME was poorly cared for by the nhs (understated). On that awful descent I did so many highly inappropriate things because I was illmanaged. After a while each knock down from things such as a trip out with unforeseen exertion, an enforced exhausting hospital trip to miles away saw my “return” to a lower level of function. This was difficult to deal with as I wasn’t prepared for continued deterioration, expecting to just get better, so I was ill prepared for the PEM caused by things that had recently been ok. My baseline was sinking.

I think in ME some of us have a resilience at first, a number of lives, our bodies can bend and heal a few to many times so exertion doesn’t seem long term harmful (some just deteriorate rapidly from anything) but whether those “lives” run out or whether it’s just the more severe you are the more vulnerable to repeated exertion from life, it’s resilience starts to go. I’ve had exertion I simply have not recovered from, throw in another like it and I will go down further..

I can’t at all personally not think if I’d been well managed there’s no way my illness would have progressed to this level, I don’t consider myself having progressive ME , decline despite all and whatever, but poorly managed ME which is detrimental AFAIC like poorly managed diabetes, or harm from eye strain or anything.

 

[Snowdrop]

@Cinders66

I understand your position. And I don't disagree that what we do can make our illness permanently worse but I don't know if for some/many/all whether the illness might slowly worsen over time anyway. I also agree that it seems some people have more resilience either for some or all of the time. None of this is nailed down. It would be so good to be talking about how our charities are pulling for us and/or how a medically proven treatment is going but here we are.

It would be good to get our individual stories out there. I'd do it if I could but even if I had the capacity I have a list of things that desperately need attending to.

 

[alex3619]

I would not characterise it as 'have a mild form of ME'.

One of the problems people do not understand is how bad mild ME is. You need, under most definitions, at least a fifty percent loss of functional capacity to be even classed as mild. That means half your capacity to engage in life is gone. It only gets worse than there, till at the very severe end there is no engagement with life as people understand it, and even staying alive is a painful struggle, and sometimes we fail.

 

[Ravn]

Interesting reflections @Sly Saint! Had to think about that. My first reaction as a housebounder was that it's us at the severe end who get ignored, and that the mild and moderate ones get most of the attention. Then I realised that my view was based on my own experience of being unable to travel and participate in research studies, plus the impression I have that most research is being done on mild-moderate patients. So I was looking at research.

Whereas you were looking at patient information leaflets and media coverage. And there's certainly lots of potential for misinterpretation (and too often plain misinformation, too) to be found there, totally agree.

@Cinders66 suggestion to push the 75% of patients unable to work is a good one. In general I think a stronger focus on functionality, or lack thereof, instead of on symptoms would be a good move. So often you see the question 'What is ME?' answered along the lines of 'As well as persistent fatigue patients may have a sore throat and difficulty sleeping'. Followed by '25% are so severely affected they cannot leave the house or even their bed'. To which the uninitiated reader responds quite understandably with 'Whaaat? Because of a sore throat?!'.

@Cinders66 makes another good point about “most people getting better”. That may even be true as in many will feel a little better once they master pacing – but that's not how most people would interpret “getting better”. For most “getting better” means getting back to normal or almost. So almost a guarantee for misinterpretation there.

Agreed @alex3619 the expression 'mild ME' should be banned outright. Nobody in their right mind would consider a 50% reduction in function as 'mild'. We do have a lot of problems with the language used about ME, haven't we!

Just had an idea just now – thinking aloud, don't expect anything well thought through – but how about we borrow some language from cancer? They have precancerous lesions, stage 1, stage 2 and through to stage 4 (I think), and terminal cancer. Everybody will take a precancerous lesion seriously as something that may not be causing a lot of symptoms right now but that needs to be attended to so as to minimise the risk of it progressing to something more serious. Everybody thinks any sort of cancer diagnosis is bad, including stage 1 ('mild' never comes into it), but also knows that stage 4 is an awful lot worse. The use of 'stages' signals the risk of progression as well as the hope for stabilisation, or even remission for a few lucky ones. That sort of language strikes me as more useful than our vaguely and misleadingly defined mild, moderate, severe and very severe. Your thoughts?

 

[Snow Leopard]

There is no "mild" ME, people should stop calling it that.

 

[JaimeS]

A lot to say on this.

pwME w/severe presentation have a hard time engaging

Because it's so tough to get severe pwME to engage in studies -- that's a good part of the problem. The population you're talking about is often too weak to engage.

pwME w/severe presentation cost more to engage ($ and health-wise)

Having discussed the SIPS study in some depth at Stanford, there are serious barriers beyond initial engagement. You need to hire people to visit severe patients in person; they cannot come to see you. Even epi studies and qualitative studies pose these barriers, as patients might be too weak to speak for long.

These barriers cost money to overcome, and ME research remains criminally underfunded. The SIPS study was 20-ish people only, as I recall!

Numerous ethical barriers on engaging w/the worst affected

(Yes, yes -- this is why everyone hates moral philosophy professors.)

There are some ethical barriers that are impossible to overcome: while there are pwME who would probably love to engage if they felt a bit better, knowing someone WILL crash if they participate in your study -- for a month or longer, a year, maybe -- and still saying "won't you please come and help"?

It's ethically dicey at best.

And moderate people and minor people are still affected enough that it significantly impacts our everyday lives. Presumably the biomarker(s) that exist should be dramatic enough to see, if we are looking in the right place, regardless. And in that case, how is it ethical to do this work on the sickest of the sick?

Is it even superior scientifically/medically? Perhaps you want the 'average' patient to understand the median case, not the worst off -- which might, in fact, yield results you would never see in a minor or moderate patient because of processes that only engage in the worst of the worst. That is, these findings may not identify the median patient or elucidate mechanisms valid to their illness process at all.

And speaking of ethical considerations, there is a whole section in IRB training on 'vulnerable patient populations' and we tick every box: as a patient population with no treatment or cure, with a low number of working medical specialists, a high level of debility, and facing considerable stigma, research on ME will by its nature be ethically fraught. This is all compounded in research with severe pwME, where nearly every reason why we fall into that category is underlined in red ink. Vulnerable patient populations will give you more than a person less vulnerable would give you; they will give you anything you ask for. 30-mL of blood. Are you sure you don't want more? Did you need a skin sample? A muscle biopsy? CSF? Take it, take everything, anything that will help. Researchers who've worked in other fields comment -- at length -- how tractable we are, how eager we are to participate, how in love we are with the science, how much we read, compared to the other populations they've worked with. (Spoiler alert: it's because we are measurably more desperate.)

Explaining why especially vulnerable patient populations also means poorer research on average is probably its own essay. It suffices to say that history is littered with these stories, and that desperation -- both the researcher's and the patients' -- plays a starring role. Wakefield comes immediately to mind.

Some clinicians will not diagnose severe ME

Finally, there is some diagnostic uncertainty around the most seriously ill patients. Some clinicians might wonder if there isn't something more wrong than "just ME" with the severe patients.

I do not find this credible. Anyone who's swung from moderate to minor and back again, as I have and as most of you have, would never question that a 'minor' patient like me could have the same disease as someone bedbound. But I think that concept might be very challenging for healthy people to grasp. And I also think there is inherent 'value' for clinicians in making this judgement; it means that the severe patient falls outside their purview. Not their responsibility, awesome! (The right answer isn't typically the one that yields the most convenient result, were it true... but this affects decision-making for sure.)

My own (subjective) conclusions

All that said, I am for the participation of severely ill people with ME if they wish it. And I will help facilitate it for those who do wish it. I do ask that people in a 'severe' place ask themselves if their participation will provide insight that can't be gained elsewhere.

If we are all measurably disabled, surely what has disabled us will be measurable. The implication is a severe patient's body will not unlock a scientific secret that a minor or moderate person's cannot.

I want us to make scientific progress, but I simply am not clear on the logic that studying the severely ill at great expense to themselves provides more insight than the participation of people with ME more on the minor/moderate end of things. We have no proof of it. So it's direct harm against my people for no valid reason I can prove, sink my teeth into. Happy to be proved wrong, but no reason to suppose I am as of now.

 

[DokaGirl]

I like @Ravn's idea of stages. Another medical description I've seen is levels; I prefer stages.

We have enough trouble with the misleading term "cfs"; add in "mild cfs", and it becomes meaningless to outsiders.

Very good point, @alex3619. To be diagnosed as having ME one needs to have a 50 percent reduction in activity/function - to call this "mild" is nonsense. I don't think other diseases have such a tough yardstick. If a person loses 50 percent function with diabetes, I don't think this would be called "mild". Same with heart disease etc.

 

[Cinders66]

A lot to say on this.

pwME w/severe presentation have a hard time engaging

Because it's so tough to get severe pwME to engage in studies -- that's a good part of the problem. The population you're talking about is often too weak to engage.

pwME w/severe presentation cost more to engage ($ and health-wise)

Having discussed the SIPS study in some depth at Stanford, there are serious barriers beyond initial engagement. You need to hire people to visit severe patients in person; they cannot come to see you. Even epi studies and qualitative studies pose these barriers, as patients might be too weak to speak for long.

These barriers cost money to overcome, and ME research remains criminally underfunded. The SIPS study was 20-ish people only, as I recall!

Numerous ethical barriers on engaging w/the worst affected

(Yes, yes -- this is why everyone hates moral philosophy professors.)

There are some ethical barriers that are impossible to overcome: while there are pwME who would probably love to engage if they felt a bit better, knowing someone WILL crash if they participate in your study -- for a month or longer, a year, maybe -- and still saying "won't you please come and help"?

It's ethically dicey at best.

And moderate people and minor people are still affected enough that it significantly impacts our everyday lives. Presumably the biomarker(s) that exist should be dramatic enough to see, if we are looking in the right place, regardless. And in that case, how is it ethical to do this work on the sickest of the sick?

Is it even superior scientifically/medically? Perhaps you want the 'average' patient to understand the median case, not the worst off -- which might, in fact, yield results you would never see in a minor or moderate patient because of processes that only engage in the worst of the worst. That is, these findings may not identify the median patient or elucidate mechanisms valid to their illness process at all.

And speaking of ethical considerations, there is a whole section in IRB training on 'vulnerable patient populations' and we tick every box: as a patient population with no treatment or cure, with a low number of working medical specialists, a high level of debility, and facing considerable stigma, research on ME will by its nature be ethically fraught. This is all compounded in research with severe pwME, where nearly every reason why we fall into that category is underlined in red ink. Vulnerable patient populations will give you more than a person less vulnerable would give you; they will give you anything you ask for. 30-mL of blood. Are you sure you don't want more? Did you need a skin sample? A muscle biopsy? CSF? Take it, take everything, anything that will help. Researchers who've worked in other fields comment -- at length -- how tractable we are, how eager we are to participate, how in love we are with the science, how much we read, compared to the other populations they've worked with. (Spoiler alert: it's because we are measurably more desperate.)

Explaining why especially vulnerable patient populations also means poorer research on average is probably its own essay. It suffices to say that history is littered with these stories, and that desperation -- both the researcher's and the patients' -- plays a starring role. Wakefield comes immediately to mind.

Some clinicians will not diagnose severe ME

Finally, there is some diagnostic uncertainty around the most seriously ill patients. Some clinicians might wonder if there isn't something more wrong than "just ME" with the severe patients.

I do not find this credible. Anyone who's swung from moderate to minor and back again, as I have and as most of you have, would never question that a 'minor' patient like me could have the same disease as someone bedbound. But I think that concept might be very challenging for healthy people to grasp. And I also think there is inherent 'value' for clinicians in making this judgement; it means that the severe patient falls outside their purview. Not their responsibility, awesome! (The right answer isn't typically the one that yields the most convenient result, were it true... but this affects decision-making for sure.)

My own (subjective) conclusions

All that said, I am for the participation of severely ill people with ME if they wish it. And I will help facilitate it for those who do wish it. I do ask that people in a 'severe' place ask themselves if their participation will provide insight that can't be gained elsewhere.

If we are all measurably disabled, surely what has disabled us will be measurable. The implication is a severe patient's body will not unlock a scientific secret that a minor or moderate person's cannot.

I want us to make scientific progress, but I simply am not clear on the logic that studying the severely ill at great expense to themselves provides more insight than the participation of people with ME more on the minor/moderate end of things. We have no proof of it. So it's direct harm against my people for no valid reason I can prove, sink my teeth into. Happy to be proved wrong, but no reason to suppose I am as of now.

Hi jamieS I realize we Are possibly opposite ends of severity but I feel your post perpetuates the issue we have had for years as severe ME being treated as the “too difficult other”. We are not other , severe ME is a grade down from moderate, with overlaps, As moderate is a grade down from mild. I don’t see why people casually lump mild-moderate together when they’re quite significantly different and then treat severe and very severe as one group of “those really sick people with so many barriers”

Whilst very severe like me struggle to participate in research the severe, not bedridden, are much more amenable and can even manage occasional Hospital trips, even a lot of very severe can do simple blood tests etc from home. There’s a vast range between not able to leave the house but still engage socially , intellectually etc quite well and the sickest of the sick. Just as there’s a vast range between able to work quite easily but not socialise and only leaving the house for a two hour trip to the park sometimes. We deserve research in our own right , like PPMS and SPMS and if it costs a few more bucks then so be it. The call should be for funds not how to ration. We might have more complex and developed forms of the illness which necessitates study on us rather than just inferring results from mild-moderate. I don’t think there are huge ethical considerations to studying severe ME I think there’s a need.

Ron Davis has also argued that the severe might be useful because they have the strongest signal, rather than being possibly irrelevant to the population as a whole. You talk of “direct harm to your people” , do you mean a diversion of funds to severe ME , yet there’s hardly any severe ME research,,.

Some of the greatest contributors to advocacy alem matthees, Tom kindon and Jessica Taylor have been severe. I also know many severe ME in U.K. able and delighted to be participating in the bio bank research which is costing extra but building up an important resource

 

[Sly Saint]

I would not characterise it as 'have a mild form of ME'.

nor would I. It was the statistics that I was interested in.

Just to clarify that I don't agree with the three tier distinction either
see my posts here:

https://www.s4me.info/posts/136365/
https://www.s4me.info/posts/135192/
https://www.s4me.info/posts/135330/

the impression I have that most research is being done on mild-moderate patients

I don’t see why people casually lump mild-moderate together when they’re quite significantly different

If you think about it, yes, all the BPS research excludes severely affected, but as far as I am aware never differentiates between 'mild' and 'moderate'.

From their point of view clubbing the two together makes sense because then they can say what they are 'studying' is applicable to 75% of pwME
And conclude that their therapies are suitable for both levels of severity.

(although of course we all know that it is not actually applicable to any).

The whole 'idea' behind it all was/is to get pwME back to work, so they had to somehow include the majority group who by definition are 'unable to work':

"People with 'moderate' CFS/ME can't move around easily and have problems continuing normal levels of daily activities. They have usually had to give up their work or education, may need to sleep in the afternoon and rest frequently between activities, and have problems sleeping at night."
(NICE guidelines)

eta: to sum up
AfME in their literature say 'some people with ME are too ill to work';
they should be saying 'the majority of people with ME are too ill to work'.

 

[Patient4Life]

To be diagnosed as having ME one needs to have a 50 percent reduction in activity/function - to call this "mild" is nonsense.

You need, under most definitions, at least a fifty percent loss of functional capacity to be even classed as mild.

I agree.

The SEID criteria words it a bit differently.

A substantial reduction or impairment in the ability to engage in pre-illness levels of occupational, educational, social, or personal activities, that persists for more than 6 months and is accompanied by fatigue, which is often profound, is of new or definite onset (not lifelong), is not the result of ongoing excessive exertion, and is not substantially alleviated by rest, and

2. Post-exertional malaise,* and

3. Unrefreshing sleep*

At least one of the two following manifestations is also required:

1. Cognitive impairment* or

2. Orthostatic intolerance

* Frequency and severity of symptoms should be assessed. The diagnosis of ME/CFS (SEID) should be questioned if patients do not have these symptoms at least half of the time with moderate, substantial, or severe intensity.



So, they don't say a 50% reduction in activity/function but should have the symptoms at least half of the time. It does not state mild but I think moderate is the term they are using for mild? I met SEID for 15 years then went into CCC. I worked full and part time during those 15 years and 7 years I worked full and part time meeting CCC but I was very sick and missing a lot of work. Anyway, I am now severe being all but housebound and needing help with errands.

 

[alex3619]

A substantial reduction or impairment in the ability to engage in pre-illness levels

There are a couple of definitions that state it like that, I think the other is Oxford. Are there more?

I am now severe being all but housebound and needing help with errands.

I use a slightly different scale, and count that as moderate. If you don't do that, and insist on mild, moderate, severe, very severe, then the severe range is too large. I count as just barely moderate, verging on severe, but on the scale you are using I would be at the bad end of severe. These scales do not reflect the reality of where we live. Or in other words, they are made-up scales that only tell us a little of what is going wrong.

We do need to get away from these ways of categorising severity. However any scale needs to reflect that we can improve on a scale, not just get worse. What we don't do, except in maybe 5% of cases, is recover enough to go below mild and stay there.

I am shocked that the 2 day CPET can find patients with an anaerobic threshold of 68. These are patients who can even exercise a tiny bit, enough to do the test. How much worse are we at the very severe end? We need better tests than CPET of course, this is just illustrative of the problem.

 

[Cinders66]

I think the 4 grades are on average ok. There do seem exceptions so a lady on AFME Facebook was saying she was bedridden yet did a degree fine from her bed, which is unusual but clearly defies the definitions out there.

Action for ME helda twitter discussion on the number of usable hours per day which was quite an interesting and alternative way to describe the debility, especially in an illness like ours defined by having to pace activity and rest. With the more severe needing more rest time. Maybe another day that might be an interesting poll, especially if we could tie that with the severity grading. Once we have strong info it might be another angle we could use, getting back to the original post, to better convey ME debilitation.

 

[alex3619]

number of usable hours per day

Hours? For me its minutes at a time, several times a day, unless the activity is very light (like typing this or an easy computer game). For activities as demanding as making a meal, I have minutes at a time several times a day ... so I eat fast meals, which are much less healthy than I should be eating. Even for computer games I rate them on the hours I can play. The very best is six hours, and that is a record (for the space survival game Empyrion), my regular games are rated at three, and too many games are rated at zero. In order to function at this level I have to swap activities a lot too. I also make meals after a rest or nap, when I am at my best.

Its very hard to just use hours. What do we even mean by functional for that time?

PS To confound this further there are long periods I only sleep two hours a day. I might rest another two. Does that mean I have 20 usable hours? At such times my capacity to make food is like 0 minutes a day, unless you count junk food out of a packet or opening a can and sticking a fork in it. Even then that is seconds per meal "prep". It also takes me a long time to eat during those events .. is that usable? Usable time might only be valid for mild patients and the lower end of moderate.

 

[Cinders66]

It’s in total so if you had ten minutes every hour for 16 hours that’s 160 minutes 2:40 hours per day. People at high end will have possibly ten or more usable hours, people at the lower end, will be very low 0-2.
Yes the level of function is difficult because useable time for someone healthy might be jogging round a park whereas in severe ME it might be having music on so maybe it would be necessary to divide into low, medium high levels of usable time to accurately reflect energy expenditure and function time available to individuals.

 

[NelliePledge]

It’s in total so if you had ten minutes every hour for 16 hours that’s 160 minutes 2:40 hours per day. People at high end will have possibly ten or more usable hours, people at the lower end, will be very low 0-2.
Yes the level of function is difficult because useable time for someone healthy might be jogging round a park whereas in severe ME it might be having music on so maybe it would be necessary to divide into low, medium high levels of usable time to accurately reflect energy expenditure and function time available to individuals.

I think low medium and high isn’t subtle enough to reflect the different levels of functioning percentage compared to when healthy gives a better idea.