Is the NIH/CDC going to use the right PEM definition for all their future research? Do patients need to act? Deadline 31 Jan

[Alice]

The NIH/CDC are deciding on the “common data elements“, CDE, that must be collected in all studies they fund. And they’ve asked for patient comments on the draft proposals by 31 January.

Perhaps the most important of the CDEs covers PEM, as the cardinal symptom of the illness. The PEM subgroup has proposed a questionnaire that will play a key role in defining PEM and I have concerns about its suitability. I’d like to hear what other patients think.

I should say that its choice - the PEM subscale from Lenny Jason’s DePaul Symptom questionnaire, DSQ, - seems to be the only credible option right now. And the subgroup recognises many of the DSQ’s limitations. However, I feel we need a clear plan to urgently develop a better option.

The questionnaire will help define who has PEM and who does not (in some cases it will be the only measure used). If it’s inaccurate, it risks including patients who don’t have the illness, weakening research, and excluding patients who should be, making recruitment harder and leading to smaller studies, again weakening research.

The DSQ assesses post-exertional malaise by asking patients to rate severity and frequency of five symptoms over the last six months:

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

My feeling is that these question circle around PEM rather than really capturing its essence. How do others feel about this?

A 2017 study by Murdock found that the PEM subscale did differentiate patients from healthy controls, but only when the volume was turned up quite high (score >20/40). A really good PEM measure should do that more easily – PEM is not a normal, healthy experience.

Interestingly, the subgroup itself has adopted the Institute of Medicine’s definition of PEM (now the National Academy of medicine, NAM). As it put it:

Post-exertional malaise is defined as an abnormal response to minimal amounts of physical or cognitive exertion that is characterised by (my summary, full text in a later post):

• A flare of some or all of an individual’s symptoms,
• with an immediate or delayed onset and
• with prolonged recovery.
• Severity and duration of symptoms are out of proportion to the initial trigger.
• There is a loss of functional capacity and/or stamina.

Which to me looks like a good description of PEM and substantially different from the DSQ. So, on the one hand, the subgroup have adopted the NAM definition, while on the other they have selected the DSQ to measure it, and that doesn’t seem to stack up.

Of course, what’s actually needed is a short, validated questionnaire that can be used in studies. We don’t have that yet for anything but the DSQ.

For now, it’s the right call to use the DSQ, but I believe we need a clear plan to urgently develop a replacement that starts with patient input. Only patients experience PEM, so their input is crucial.

I’ve started this thread to hear if other people share my concerns. I’d appreciate any answers to (any of) the following three questions:

1. Does the proposed five items questionnaire fall short of properly capturing post-exertional malaise?
   
2. If so, should we be asking for a timetabled plan to urgently develop a better alternative?
   
3. I also have concerns that the way symptoms are scored could give misleading results - see next post. Again, is this an issue for anyone else?

IMPORTANT. This is not intended as a criticism of Professor Leonard Jason, who has been a lonely pioneer of case definitions and post-exertional malaise in particular. Without the research of him and his team there would be nothing to use now. Likewise, it’s not a criticism of the working group (co-chaired by Lily Chu and patient advocate Mary Dimmock). This has produced many good recommendations (including using the DSQ for PEM at first) and has highlighted many of the weaknesses of the DSQ.

This, though, is about how PEM will be defined in every N I H and CDC study, every biomedical study, so it needs to be as good as it can be, as soon as possible, to produce the best possible research.

Can anyone help with more info e.g. more on the DSQ, especially the PEM questions, which I believe were discussed on PR in the past? I’ve read the research myself years back but am too ill now to revisit. Just doing this has been a huge effort.

@Woolie is a questionnaire expert, @Adrian and @Graham know a lot too.

I know when I was less severely ill and didn't know any better I still exercised. I could exercise at that point, but as you say @Barry , the aftermath was very,very different.

The more I tried to exercise the worse it and less able to exercise I became. This is the opposite of my experience of exercise prior to becoming ill.

When healthy the post exercise aches could often be eased by gentle exercise and movement. With PEM I found, when I was still well enough to try, further exercise and movement made the symptoms rapidly worse.

The IOM description resonates with me. In addition I think we need to add some of the objective signs of PEM. Such as PEM shows up in a reduced (or if really over exerted an increased) morning resting heart rate compared to average morning resting heart rate the next day. Along with a much more reactive HR - much spikier up and down. Also that extreme PEM can last years from inordinately tiny events/exposures to triggers. Also the IOM description fails to mention other triggers other than physical or cognitive exertions that can cause PEM e.g. food/chemicals/ noise/light, good and/or bad emotional events.

 

[Alice]

The way the symptoms are scored might give misleading results

My other big concern with the questionnaire, which again relates to its accuracy, is about how PEM is scored. I think we need to score in a way that reflects how patients try very hard to avoid PEM. Here’s the questioin

“For the following questions, we would like to know how often you have had each symptom and how much each symptom has bothered you over the last 6 months.“ Each is scored 0-4, and a PEM diagnosis requires a score of at least 2 on both frequency and severity for any of the 5 items. These scores corresponds to at least moderate severity and PEM half of the time or more.

I think the frequency question looks at things the wrong way, and am pretty sure there are plenty of mecfs patients with PEM who experience it less than half the time - and so who would be excluded from every NIH/CDC study.

The problem is that PEM is a function of disease level, but also of pacing and life circumstances. As the report note elsewhere, “many ME/CFS patients use strategies to avoid and/or to minimize the impact of PEM”.

The subgroup is clearly aware of the problem, with the case report form emphasising the need for researchers to interpret the questionnaire finding:

“In making this [PEM] determination, the researcher or clinician will need to consider whether there are other conditions, such as overwork, that could result in a false positive DSQ PEM subscale response. On the other hand, the researcher or clinician should also consider whether the study participant responded negatively because, for instance, they carefully manage their energy expenditures with pacing to avoid episodes of PEM.

In addition to asking questions about workload and pacing, the researcher may also ask what happens to the study participant if/when they engage in physical or mental activity and whether there are activities they avoid because it exacerbates symptoms.”

This is all very good, and important.

But I think we need a questionnaire that allows the patient to give more appropriate information in the first place. This could be with a question on what happens if/when they engage in physical or mental activity. Or to what extent the patient has to change their life to avoid PEM – I suspect that for most patients it’s “a great deal”, and any questionnaire should capture that.

A major reason for a mandatory questionnaire across studies is to standardise approaches, whereas relying on researcher judgement to interpret questionnaire scores will do the opposite.

Again, my views – what do other patients think?

Thanks for your patience with my long posts. Please bear in mind that the consultation document ran to 28 pages. And thanks for all work done by the PEM subgroup.

Yes - our challenge is to avoid PEM at all costs so much so that we hope to score zero on frequency and zero on severity. This really leads back to the need for our physiological abnormalities to be measured. It would be far more useful to know how much time we spent over our anaerobic threshold and how much time at resting heart rate zone over the time when talking about symptoms or what is the maximum that you can safely do before triggering PEM .

 

[Alice]

It's not always optional though: at a severe enough level, just continuing to be alive is enough to trigger it, because there is literally too little energy in the system to ever stabilise/for any significant length of time.

In this kind of case, triggers include sensory input, over which a person may have no control.

For those lucky enough to be able to live within their energy envelopes, that's great, but I think we should be a bit careful of anything that seems to suggest that patients can always fix it, or avoid it.

Perhaps along with a description/definition, we just need to additionally include that PEM puts a hard physical ceiling on patients' functionality, at a level approximately determined by level of severity.

ETA cross-posted with Invisible Woman

?? but there is not a hard physical ceiling. It appears that PEM fluctuates in relation to cumulative load and the triggering event. The impact changes over time. I think it would be good to devise a series of PEM tests for people doing the same task and both a between people and individual tests. My gut feeling is that disease severity and PEM is reflected in HR traces and certainly very easy to tell from a normal HR trace.

 

[Alice]

Personally, I'd add something to reflect that symptoms not normally felt when pacing is sufficient can be brought on by over exertion I.e. recently, following over exertion, I was affected by IBS, something that is not normally an issue for me.

Yep an emotional drama sets off IBS for me. It is odd but I have a different symptom exacerbation pattern for different triggering events. Chemicals and food lead to a "coma" wiped out sleep. Exercise to a sore throat, headache, glands. Cognitive - tinnitis...Eventually if I don;t rest the symptoms become a big PEM mess but the initial warning signals are quite distinct.

 

[Alice]

Yes - our challenge is to avoid PEM at all costs so much so that we hope to score zero on frequency and zero on severity. This really leads back to the need for our physiological abnormalities to be measured. It would be far more useful to know how much time we spent over our anaerobic threshold and how much time at resting heart rate zone over the time when talking about symptoms or what is the maximum that you can safely do before triggering PEM .

I don't like the word bothered- my life has ended and I am devastated NOT bothered.

 

[Alice]

I couldn't read all you posted so I will just add to what you summarized above.

• A flare of some or all of an individual’s symptoms which includes but is not limited to fatigue,

• with an immediate or delayed onset of 24-72 hrs and

• with prolonged recovery which can take 1 day to 2 weeks.

• Severity and duration of symptoms are out of proportion to the initial trigger whether it was physical or mental exertion or both.

• There is a loss of functional capacity and/or stamina.

Each bullet should have further explanations such as an explanation of "fatigue" in that it is not a healthy "tiredness" (perhaps the last bullet is describing it but perhaps that should be the second bullet) and what is meant by "recovery". And if anyone is able to briefly describe what fatigue in our disease means as well as what a recovery from symptoms is as no doubt a patient will still experience their symptoms even when they recover after a trigger, I would appreciate it because I am unable to put it into words.

Also, "functional capacity" and "stamina" may have to have a short explanation because very often patients do not understand what these words are conveying due to lack of education or English not being their first language and/or their cognitive abilities being compromised. Prior to my becoming very aware of my disease, I would bet I would not have answered these questions properly. I could barely read and get through the forms at my rheumatologist's office. Due to my cognitive problems, I even forgot what the word cognition meant.

The idea that PEM lasts a few days or weeks is at odds with some peoples reality of months/years/decades/may be never able to get back to pre trigger functional capacity.

 

[Alice]

Also what I call compound PEM - kinda like compound interest:

Day1 do something that will trigger PEM and don't realize it

Day 2 so pleased you got away with yesterday - maybe I could achieve a little extra task today as well

Day 3 still ok - on a roll here

Day 4 - 3 days past the trigger and the first lot of PEM hits....payback from the other days to follow... and will hit me while I am flattened by the first lot.

It took me years to figure out what was going on and realize this was PEM. Although I didn't know what It was called. It's also why I don't believe this increasing activity such as GET works. If I have a 2-3 day delay for PEM then I could be building up to a world of pain during the delay period.

Getting into compound PEM will trigger a crash or relapse for me and seriously stuff things up for many a miserable month.

 

[Alice]

Yes, this seems correct. If we can research those who are experiencing PEM, those that can probably get to a researcher do experience PEM and not patients experiencing severe relapses and crashes anyway, once we get a biomarker for them then we will have a biomarker on those that can't get out.

They are also doing research on the severe, and the Open Medicine Foundation at Stanford did find the metabolic differences that can probably be a biomarker, but this has to be expanded and replicated.

But the point here is to define PEM, the type experienced by most patients most of the time. They not only want the largest group possible in studies, they want to have a biomarker for PEM itself.

Don't all patients experience PEM if they over exert and/or are exposed to triggers.

 

[Alice]

me too. Another reason to be careful not to be too prescriptive?

Me too- I get little warning signs now that I am tuned into my body with PEM hitting like a truck on day 3 if I ignore Day 1's warning signs. On Day 2 I can feel on top of the world and wired to do anything. Now that I am HR monitoring I can see that my HR and HRV data are usually bad on day 2 indicating the need to rest up to avoid PEM.
My concern is that the definition is to be used for research yet doesn't ask about our objective markers which many of us have data on and would made a good part 2 to the definition. Educating Dr/patients and researchers about the power of using objective HR data.

 

[Alice]

Hmmm? I always just took "exertion" to mean anything beyond me laying down, being still, being quiet doing absolutely nothing whatsoever.

I like the term exertion as to me it means anything that is not resting and it includes physical and cognitive - the other triggers need to be included as well.

 

[Alice]

Anecdotally- I know several patients whose resting heart rate is so variable at all times but is not significantly worse/increased during PEM than when they are at baseline.
And if someone is on medication that helps control their heart rate, how would increased heart rate as part of a PEM definition, impact the assessment of PEM for them?

A definition can be multi faceted. I see heart rate data as a second tier of information and not the primary definition but for people pacing and controlling their environment as much as possible heart rate abnormality patterns caused by exertion/triggers appear to be distinctive. The heart rate medications appear to reduce the HR but the PEM patterns are still being observed. I think we need to keep hammering home the fact that the effects of PEM can be measured, monitored and quantified. I'd suggest that those people with highly variable morning resting heart rates are either not taking it consistently ie say as soon as wake up or after going to the toilet each morning OR they are doing a whole range of things day in day out and neither ordinary pacing nor pacing with a heart rate monitor.

 

[Simone]

The poll is now live, read all about it here

In the end we stripped it down to the bare bones to make it accessible to as wide an audience as possible, and so it doesn't reflect the complexity of the debate here.

Thanks for setting this up, @Simon M. Will there also be a written submission collating the nuances of this discussion to feedback to NIH/CDC?

 

[Alice]

Background information that many will want to skip J

Various extracts from the proposals that highlight what a thorough job the PEM subgroup has done, and illustrates some of the issues covered in my first post.

PEM will be an essential part of the case definition of ME/CFS:

The “PEM Determination” is a Core CDE instrument to be used across all research studies as a common method for ascertaining and recording the presence or absence of PEM as a case defining symptom in each individual study participant.

Why the DSQ was chosen:

While not perfect, the PEM subscale of DSQ is the best choice at this time for a standard method of identifying the existence of PEM in a research study participant... has been tested and used in several ME/CFS studies, has been evaluated in multiple diseases, includes a PEM subscale, and has been used by different researchers.

The recommended core method for assessing PEM is a 2-step process in which the study participant responds to the DSQ PEM questions and the researcher then evaluates those responses in light of other information (e.g. study participant interview, physical examination, objective testing) about the study participant to determine whether the study participant experiences PEM or not.

Limitations

There is a dearth of studies asking participants about their experiences of PEM in an open-ended manner, which is needed….

The instrument does not assess the full range of symptoms that could be exacerbated by PEM and only one item addresses the sometimes delayed onset/ prolonged duration of PEM ("Next day soreness or fatigue after non-strenuous, everyday activities.")

● The studies published to date primarily evaluate the DSQ in ME/CFS compared to healthy controls, not in other fatiguing conditions or conditions where there could be diagnostic ambiguity. Recent research has shown a difference between ME/CFS and MS study participants.

● The use of the DSQ PEM subscale as a stand-alone instrument has not been separately validated although as noted above, its use has resulted in a high prevalence of PEM being reported in ME/CFS study participants.

Need for further research

● The instrument will need to be further evaluated to ensure it accurately reflects the symptom of PEM. (…Further research is needed to address these limitations.)

6. Unmet needs;

1. Further development and refinement of the Core PEM Instrument [includes DSQ] and CRF.

> In my view this needs to be much stronger and should say replacement or development. It may be a new PEM questionnaire would be no more effective; we need to find out urgently. And the whole process needs a tight timetable.

Full version of the NAM (formerly IOM) PEM definition

 

[Alice]

I'm a bit confused as teh questionaire didn't ahve NAM which i wouldl have choosen over IOM.

 

[Sasha]

The IOM description resonates with me. In addition I think we need to add some of the objective signs of PEM. Such as PEM shows up in a reduced (or if really over exerted an increased) morning resting heart rate compared to average morning resting heart rate the next day.

Is there published evidence for that, Alice? I vaguely remember Nancy Klimas saying that if your morning HR is high you should be more careful that day but I didn't know she'd published on it.

 

[susanna]

The NIH/CDC are deciding on the “common data elements“, CDE, that must be collected in all studies they fund. And they’ve asked for patient comments on the draft proposals by 31 January.

Perhaps the most important of the CDEs covers PEM, as the cardinal symptom of the illness. The PEM subgroup has proposed a questionnaire that will play a key role in defining PEM and I have concerns about its suitability. I’d like to hear what other patients think.

I should say that its choice - the PEM subscale from Lenny Jason’s DePaul Symptom questionnaire, DSQ, - seems to be the only credible option right now. And the subgroup recognises many of the DSQ’s limitations. However, I feel we need a clear plan to urgently develop a better option.

The questionnaire will help define who has PEM and who does not (in some cases it will be the only measure used). If it’s inaccurate, it risks including patients who don’t have the illness, weakening research, and excluding patients who should be, making recruitment harder and leading to smaller studies, again weakening research.

The DSQ assesses post-exertional malaise by asking patients to rate severity and frequency of five symptoms over the last six months:

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

My feeling is that these question circle around PEM rather than really capturing its essence. How do others feel about this?

A 2017 study by Murdock found that the PEM subscale did differentiate patients from healthy controls, but only when the volume was turned up quite high (score >20/40). A really good PEM measure should do that more easily – PEM is not a normal, healthy experience.

Interestingly, the subgroup itself has adopted the Institute of Medicine’s definition of PEM (now the National Academy of medicine, NAM). As it put it:

Post-exertional malaise is defined as an abnormal response to minimal amounts of physical or cognitive exertion that is characterised by (my summary, full text in a later post):

• A flare of some or all of an individual’s symptoms,
• with an immediate or delayed onset and
• with prolonged recovery.
• Severity and duration of symptoms are out of proportion to the initial trigger.
• There is a loss of functional capacity and/or stamina.

Which to me looks like a good description of PEM and substantially different from the DSQ. So, on the one hand, the subgroup have adopted the NAM definition, while on the other they have selected the DSQ to measure it, and that doesn’t seem to stack up.

Of course, what’s actually needed is a short, validated questionnaire that can be used in studies. We don’t have that yet for anything but the DSQ.

For now, it’s the right call to use the DSQ, but I believe we need a clear plan to urgently develop a replacement that starts with patient input. Only patients experience PEM, so their input is crucial.

I’ve started this thread to hear if other people share my concerns. I’d appreciate any answers to (any of) the following three questions:

1. Does the proposed five items questionnaire fall short of properly capturing post-exertional malaise?
   
2. If so, should we be asking for a timetabled plan to urgently develop a better alternative?
   
3. I also have concerns that the way symptoms are scored could give misleading results - see next post. Again, is this an issue for anyone else?

IMPORTANT. This is not intended as a criticism of Professor Leonard Jason, who has been a lonely pioneer of case definitions and post-exertional malaise in particular. Without the research of him and his team there would be nothing to use now. Likewise, it’s not a criticism of the working group (co-chaired by Lily Chu and patient advocate Mary Dimmock). This has produced many good recommendations (including using the DSQ for PEM at first) and has highlighted many of the weaknesses of the DSQ.

This, though, is about how PEM will be defined in every N I H and CDC study, every biomedical study, so it needs to be as good as it can be, as soon as possible, to produce the best possible research.

Can anyone help with more info e.g. more on the DSQ, especially the PEM questions, which I believe were discussed on PR in the past? I’ve read the research myself years back but am too ill now to revisit. Just doing this has been a huge effort.

@Woolie is a questionnaire expert, @Adrian and @Graham know a lot too.

 

[susanna]

The NIH/CDC are deciding on the “common data elements“, CDE, that must be collected in all studies they fund. And they’ve asked for patient comments on the draft proposals by 31 January.

Perhaps the most important of the CDEs covers PEM, as the cardinal symptom of the illness. The PEM subgroup has proposed a questionnaire that will play a key role in defining PEM and I have concerns about its suitability. I’d like to hear what other patients think.

I should say that its choice - the PEM subscale from Lenny Jason’s DePaul Symptom questionnaire, DSQ, - seems to be the only credible option right now. And the subgroup recognises many of the DSQ’s limitations. However, I feel we need a clear plan to urgently develop a better option.

The questionnaire will help define who has PEM and who does not (in some cases it will be the only measure used). If it’s inaccurate, it risks including patients who don’t have the illness, weakening research, and excluding patients who should be, making recruitment harder and leading to smaller studies, again weakening research.

The DSQ assesses post-exertional malaise by asking patients to rate severity and frequency of five symptoms over the last six months:

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

My feeling is that these question circle around PEM rather than really capturing its essence. How do others feel about this?

A 2017 study by Murdock found that the PEM subscale did differentiate patients from healthy controls, but only when the volume was turned up quite high (score >20/40). A really good PEM measure should do that more easily – PEM is not a normal, healthy experience.

Interestingly, the subgroup itself has adopted the Institute of Medicine’s definition of PEM (now the National Academy of medicine, NAM). As it put it:

Post-exertional malaise is defined as an abnormal response to minimal amounts of physical or cognitive exertion that is characterised by (my summary, full text in a later post):

• A flare of some or all of an individual’s symptoms,
• with an immediate or delayed onset and
• with prolonged recovery.
• Severity and duration of symptoms are out of proportion to the initial trigger.
• There is a loss of functional capacity and/or stamina.

Which to me looks like a good description of PEM and substantially different from the DSQ. So, on the one hand, the subgroup have adopted the NAM definition, while on the other they have selected the DSQ to measure it, and that doesn’t seem to stack up.

Of course, what’s actually needed is a short, validated questionnaire that can be used in studies. We don’t have that yet for anything but the DSQ.

For now, it’s the right call to use the DSQ, but I believe we need a clear plan to urgently develop a replacement that starts with patient input. Only patients experience PEM, so their input is crucial.

I’ve started this thread to hear if other people share my concerns. I’d appreciate any answers to (any of) the following three questions:

1. Does the proposed five items questionnaire fall short of properly capturing post-exertional malaise?
   
2. If so, should we be asking for a timetabled plan to urgently develop a better alternative?
   
3. I also have concerns that the way symptoms are scored could give misleading results - see next post. Again, is this an issue for anyone else?

IMPORTANT. This is not intended as a criticism of Professor Leonard Jason, who has been a lonely pioneer of case definitions and post-exertional malaise in particular. Without the research of him and his team there would be nothing to use now. Likewise, it’s not a criticism of the working group (co-chaired by Lily Chu and patient advocate Mary Dimmock). This has produced many good recommendations (including using the DSQ for PEM at first) and has highlighted many of the weaknesses of the DSQ.

This, though, is about how PEM will be defined in every N I H and CDC study, every biomedical study, so it needs to be as good as it can be, as soon as possible, to produce the best possible research.

Can anyone help with more info e.g. more on the DSQ, especially the PEM questions, which I believe were discussed on PR in the past? I’ve read the research myself years back but am too ill now to revisit. Just doing this has been a huge effort.

@Woolie is a questionnaire expert, @Adrian and @Graham know a lot too.

 

[susanna]

The De Paul questionnaire is inadequate to describe the symptoms of PEM. It fails to capture the extraordinary nature of PEM and misses out on essential aspects. Eg, asking about frequency of symptoms is irrelevant and misleading. PEM, as the name suggests, does not arrive on schedule but is contingent on activity. ‘Fatigue’ should also be avoided as it minimises PEM. There is a ceiling effect, excluding the counting of minor activities which can trigger PEM.

The NAM questions are relevant but cover only some aspects.

A longer and more precise set of questions need to be asked in order to reflect the essential importance of the symptom. If patients can relate to the questions, it should be worth it. Here are some suggestions:

1. The SF-36 scale should be adapted (if possible, considering copyright issues). Or a similar questionnaire may need to be constructed. Re each of the activities in the SF- 36 scale, ask, How often can you do each of these activities without feeling worse afterward? Every day, Once or twice a week, Every month, Less than once a month, Never. The list of activities should be refined to include even finer movements to allow for the more severely affected.

2. Symptoms should be spelt out in more detail with degree of symptoms, if only to show the abnormality of them occurring after activity.

Eg Which of these symptoms do you experience after more activity than usual, and what is their impact?

For each symptom, Not at all, Same as usual, A bit worse than usual, A lot worse than usual.

Symptoms, heaviness, weakness, sleepy feeling, loss of co-ordination, difficulty thinking/concentrating, Making simple mistakes, tingling or pricking in some body parts, muscle twitching, muscle pain, joints feel weak/loose/painful, sore throat, flu-like symptoms, headache, difficulty standing, dizziness, breathlessness, difficulty breathing, irregular heartbeat etc. (This list is biased toward my symptoms)

Does your heart-rate increase or decrease after activity? Does this change last longer than usual? How long does it last?

3. How long do your post activity symptoms last? Hours, days, weeks, longer?

4. Do your symptoms start immediately after or during activity or are they delayed?

5. How long have you had these symptoms worsening after activity/ exercise?

6. Have your symptoms after activity got better, worse or stayed much the same over time?

These symptoms should be correlated with length, severity and progress of illness.

On the basis of these questions, an index of PEM severity could be produced by those more mathematically sophisticated than I am. Subgroups based on the type of PEM experienced could be tested for.

These are some preliminary suggestions.

 

[susanna]

The De Paul questionnaire is inadequate to describe the symptoms of PEM. It fails to capture the extraordinary nature of PEM and misses out on essential aspects. Eg, asking about frequency of symptoms is irrelevant and misleading. PEM, as the name suggests, does not arrive on schedule but is contingent on activity. ‘Fatigue’ should also be avoided as it minimises PEM. There is a ceiling effect, excluding the counting of minor activities which can trigger PEM.

The NAM questions are relevant but cover only some aspects.

A longer and more precise set of questions need to be asked in order to reflect the essential importance of the symptom. If patients can relate to the questions, it should be worth it. Here are some suggestions:

1. The SF-36 scale should be adapted (if possible, considering copyright issues). Or a similar questionnaire may need to be constructed. Re each of the activities in the SF- 36 scale, ask, How often can you do each of these activities without feeling worse afterward? Every day, Once or twice a week, Every month, Less than once a month, Never. The list of activities should be refined to include even finer movements to allow for the more severely affected.

2. Symptoms should be spelt out in more detail with degree of symptoms, if only to show the abnormality of them occurring after activity.

Eg Which of these symptoms do you experience after more activity than usual, and what is their impact?

For each symptom, Not at all, Same as usual, A bit worse than usual, A lot worse than usual.

Symptoms, heaviness, weakness, sleepy feeling, loss of co-ordination, difficulty thinking/concentrating, Making simple mistakes, tingling or pricking in some body parts, muscle twitching, muscle pain, joints feel weak/loose/painful, sore throat, flu-like symptoms, headache, difficulty standing, dizziness, breathlessness, difficulty breathing, irregular heartbeat etc. (This list is biased toward my symptoms)

Does your heart-rate increase or decrease after activity? Does this change last longer than usual? How long does it last?

3. How long do your post activity symptoms last? Hours, days, weeks, longer?

4. Do your symptoms start immediately after or during activity or are they delayed?

5. How long have you had these symptoms worsening after activity/ exercise?

6. Have your symptoms after activity got better, worse or stayed much the same over time?

These symptoms should be correlated with length, severity and progress of illness.

On the basis of these questions, an index of PEM severity could be produced by those more mathematically sophisticated than I am. Subgroups based on the type of PEM experienced could be tested for.

These are some preliminary suggestions.

 

[susanna]

As a trigger for PEM we also need to consider adding sensory overload. This can arise from social interaction, sound sight exposure to chemicals which are involved.