Studies looking at PEM - have they measured PEM or just the response to the challenge used?

Nobody doubts that, which is why it is used under carefully controlled conditions in trials.

Actually, I am not sure it is that relevant here, since we are talking about major change to feeling much worse with PEM. In the context of study of an episode of PEM you don't really need a nine or tenpin scale.

 

As I think Trish is intimating, this is not necessarily a question of degree of 'deconditioning'. Muscle change in ME might relate to a different spectrum of usage, perhaps influencing type 1 and 2 fibre dominance. That might lead to a different response to exertion in terms of measurable 'responses'. If ME is due to some shift in regulation ofenergyusage by tissues rather than anactuqal failure of metabolism then the two things might be linked in an unusual way.

People with COD or MS might contract muscles very vigorously for short periods in COPD and to overcome weakness in other groups in MS. Activity levels might look similar but the muscles might be in a very different state?

 

Also useful to do this repeatedly over time .
There is clearly a " getting progressively worse" group.
Studies using same methodology periodically may elucidate useful info.

 

If you want to measure the severity of PEM or study the correlation between the exertion and the resulting PEM fatigue, you do need something more than binary.

 

True. But fatigue is the most common symptom and could serve as the proxy for the severity of PEM. Could other symptoms be disproportional to fatigue? Could be. In my experience though, they are generally proportional.

Measuring fatigue may not have to be that difficult. If you can train an activity tracker to measure your moving speed or amount of time lying down, the measurement could become automatic. (I've tested inactive time, but that didn't have much use for MECFS.)

 

Observations from observing , listening and hand holding.

PEM is not fatigue. Every molecule in your body wants to give up.

PEM is akin to being poisoned

PEM is being trapped in a body which won't obey commands and nothing you can do can alter this. The lack.of control is truly frightening. The fear that it may not pass and ths could be the new normal .

PEM is when normal gets worse and other symptoms manifest . It's your personalised torture with no definite timeframe.

PEM is when your body is a warehouse and someone is switching the lights off bay by bay without your consent and you don't know if they will all go out. You brace yourself for eternal darkness.

PEM is wanting to say something , but your brain and mouth are having a standoff. In a world where understanding is verbal , you can't convey what's truly happening to you.

PEM is feeling like you are upside down, all the blood is rushing to your head and you can't flip the other way up.

PEM is when your limbs are lead and you cannot make them move. It's almost stroke like.

PEM is when your eyes don't work , they don't focus, peripheral tracking is off, you feel "off" , as if you are reeling , you want to hold on, to brace against tilting over- but you are lying down.

PEM induces so many different types of pain in so many different places .
From the Trotsky-esque icepick through the eye , to burning muscles, coat hanger pain , cramps, stiffness, tendons tightening .

Jaw feeling misaligned ,the joint so tight you can't open your mouth much.

Nausea killing the appetite.

The wish to be Mr Potato head and have the ability to take off your head and realign it , as if that would lessen the strain and pressure, the thumping , the heat - head feels so hot inside .
Closed eyes feel as though there's a pressure against which they strain to open lids .

Itchiness , a crawly under the skin itchiness that's like Chinese water torture or a strange sci-fi movie where you expect something to be living under your skin.

Freezing bones

Hips " off" , no comfort to be had lying down , and no means to not lie down. ( Usually tendon issues)

Pelvic floor so taut you couldn't pass anything if you could get to the loo.

The cognitive soup of brain fog. Something Parkinsonian about this .

PEM is not fatigue .

 

I'll particularly echo the feeling of having been "poisoned". I had no prior equivalent experience of this feeling (even with a hangover in my youth) and at onset, it was an instantaneous recognition that something had gone very, very wrong. Subjectively it felt systemic: deeply cellular and metabolic. The recognition that this was something new and terrible was augmented by the immediate knowledge that nothing in medical training or clinical practice had prepared me for this possibility.

 

Rather than good day/bad day testing, we need good week/bad week testing, and ideally even longer. Without this kind of longitudinal testing, it would be impossible to be sure whether the participant was at their normal baseline before any specific challenge.

And, based on the concept that pwME who are bedridden are most likely always in PEM, we need far more study of those most seriously affected. Actually, we need longitudinal testing of all severities.

 

Yes. Which goes back to needing someone to write an app that will collect information specific to ME from smart watch-type devices. Which first needs a detailed look at how body movement changes between the PEM state and relatively well rested, perhaps starting with people who're aware themselves of distinct changes in the quality of their movement as well as the type and quantity.

It would probably do nothing to explain PEM, but it might reveal the patterns over time better than anything else we've currently got.

 

I'm afraid the problem with smart watches is that they are typically very inaccurate as they are lifestyle devices rather than anything else. Some of the fitness devices are better and are sometimes highly accurate in measuring certain things but completely inaccurate in measuring others. So if you have a range of users using different devices this will cause a whole range of massive deviations simply caused by the specific device used. I believe some trials in the US are already using this type of data (for instance the Stanford Paxlovid trial).

I also think that the App you're looking for essentially already exists, it's called Visible (they use the Polar armband which is pretty accurate for basic heart rate related data, at least compared to smart watches and some other devices).

I however don't think that these devices will give us much valuable information that couldn't be tracked longitudinally without them.

 

But developers know what those things are, that's the point. Accelerometers measuring speed and direction work very well, so you can leverage that. It's impossible to tell whether someone is awake or asleep without specific, intrusive equipment, so you ignore that. Heart rate monitors work better on some than others, as do blood oxygen sensors, so you take that into consideration. Etc.

But you'd never do that in a study. An app would designed to collect specific types of data, which are known to be relevant to ME (e.g., accelerometry could potentially reveal differences in steadiness, speed, and trajectory as well as frequency), based on the known capabilities of a particular system.

(I pressed Post at this point instead of Quote, so I need to edit further!)

I haven't the energy to write notes every time I crash into the door frame because I've got PEM and have lost all ability to judge relative distance. But I never do it at other times, and smart devices are capable of picking that up. They can analyse my swimming stroke and my friend's running technique in detail, even though they're only consumer devices.

 

Were they measuring true fatigue, or were they just measuring something that appeared to be fatigue from a certain viewpoint? They might be able to reproduce results in different groups of people, but maybe that's an artifact of the questionnaires, but not actually measuring whatever mechanism is responsible for fatigue.

Does caffeine actually reduce the mechanism of fatigue, or does it just counter the perceptions of fatigue, while the actual basis of fatigue (excess or deficiency of a chemical in certain cells) might remain the same? Depending on how you write the questionnaire and interpret the results, I think you could make it look like caffeine is reducing fatigue, even though it really isn't. I don't see how they can reproducibly quantify fatigue when they can't even define fatigue.

 

Call it whatever you want, fatigue or sickness, we are talking about the same thing: whatever it is that is preventing you from doing what you need/want to do. And you can measure it only by measuring how much you are able to do. One thing for sure, you won't be able to do anything if you are not sitting up and unable to move your body/mind.

And that is what you want to measure, because doing what you need to do, not the feelings, is what matters at the end.

 

Whenever you talk about whether something is true, it can quickly devolve into metaphysics. In science though, only what predicts, not explains, something correctly is what matters. In the case of VAS, it doesn't matter whether VAS measures "true" fatigue or not as long as it correctly predicts how much the patient can do. (VAS is actually a pain, not fatigue, measure, BTW).

I'm not using the perception scale because it fails in that regard over a longer term. The perception measure is surprisingly accurate in a short term though.

 

That is an easy problem to solve. You just define your activity to include reading/listening/talking.

That said, don't you end up spending more time in bed when you are in PEM? Or, are you saying you spend equal amount time lying down whether you are in PEM or not? If time spent lying down predicts how much you can read/listen/chat, then it still is a useful measure.

 

This is very true. Even medical grade devices may not be precise enough for ME/CFS which is highly sensitive to even small amount of exertion. Doing one or two squats, for example, will hardly register. But it can bring an MECFS patients down the next day. This is the reason why I'm resorting to manual MET values in some cases.

That said, activity trackers can be quite useful for tracking motions/rests/sleep. And they could become useful for ME/CFS if they can discern the activities rather than just measuring HR or calorie expenditure. They do that to some extent, but it is all sporting activities for healthy people, not ADLs.