" Variability of postural orthostatic tachycardia in patients with myalgic encephalomyelitis..."

[Dolphin]

I wonder if there is really a big difference between those with a POTS response and those without. Or put another way, is the >=30 threshold perfect.

POT occurred in 7 patients (29 %), including severe POT in 1 (4 %), on a “good day”. In these patients, the heart rate increased from 63 ± 7 (before standing) to 103 ± 15 (the maximal rate) during the test. In the other 17 patients, the heart rate increased from 61 ± 5 to 81 ± 7 during the test.

So the heart rate went up by 20 beats per minute on average in the non-POTS group (meaning almost certainly some in the non-POTS group had increases of more than 20 beats per minute).

On a “bad day”, 11 patients (46 %) developed POT, including severe POT in 3 (13 %), during the standing test. In these patients the heart rate increased from 77 ± 9 to 114 ± 9 during the test. In the other 13 patients, the heart rate increased from 70 ± 10 to 88 ± 11 during the test.

So the non-POTS group went up by an average of 18 beats per minute.

 

[Dolphin]

Is this "without" bit right? (my underlining)
I find it a bit odd. I thought that orthostatic intolerance included all types of intolerances to being upright:

Orthostatic intolerance (OI) is a hallmark symptom of CFS or ME that restricts the daily functional capacity [5–9]. OI is characterized by the inability to maintain an upright posture without signs and symptoms such as hypotension, tachycardia, light-headedness, pallor, fatigue, weakness, dizziness, tremulousness, and nausea [10–12].

All the patients had mild or more severe symptoms of OI, which was defined as instability in maintaining the normal consciousness while standing, without the significant symptoms such as disabling fatigue, dizziness, faintness, palpitation, diminished concentration, tremulousness, sweating, light-headedness, visual disturbances, and nausea [6].

I get it now

 

[Sean]

First paragraph is okay, but the 2nd is poorly phrased. I think they meant it to say the same thing as the 1st, but just mangled the language.

 

[jimells]

Is this "without" bit right? (my underlining)
I find it a bit odd. I thought that orthostatic intolerance included all types of intolerances to being upright:

I think it's correct, although there must be a better way to write it. I had to read it a few times to conclude that if upright posture causes the significant symptoms listed, then I have OI.

Or, as they wrote it, I have to be able to stand without symptoms to avoid the label of OI, which is a silly way to state it.

The problem with the second quote is the comma between "standing" and "without".

 

[Dolphin]

Thanks @Sean and @jimells. I get it now.

 

[Sean]

I note the differences between the two lists of signs and symptoms.

Para 1
hypotension, tachycardia, light-headedness, pallor, fatigue, weakness, dizziness, tremulousness, and nausea

Para 2
disabling fatigue, dizziness, faintness, palpitation, diminished concentration, tremulousness, sweating, light-headedness, visual disturbances, and nausea

Not a big deal, I suspect, but why the differences when talking about the same phenomenon? A bit sloppy, and perhaps indulging in technical padding.

But the explanation may be no more significant than that the author's name suggests their first language is not English.

 

[SOC]

Interesting Performance Scale. In some ways I like it, and in others I have reservations. The levels 5-9 describe my improvement progression better than most scales of seen, so this one feels right to me there. It also fits what I think ME/CFS might look like over the whole range.

Where I have a question is the 0-3 range. If ME/CFS requires a 50% reduction in activity level for a diagnosis, than a 50% reduction in activity level should be mild ME/CFS, right? (Crazy, I know, to call 50% reduction "mild") I wouldn't call the inability to work a few days a month a 50% reduction in activity, although I certainly would consider it indication of a serious health issue. By that logic, patients in the 0-3 range could not be considered ME or ME/CFS patients.

I'd also add one more level (or modify PS 9) for the very severe patients who cannot take care of themselves at all, even with help. Maybe that's just a semantic issue, though.

If it were up to me, I'd say this scale represents the scale of functionality of ME/CFS pretty well, and dump the 50% reduction in functionality requirement.

It looks to me that the levels break down something like this:
PS 0-1 : no ME
PS 2-3: either no ME if requiring 50% reduction in activity level, or mild ME
PS 4-6: mild ME if requiring 50% reduction, or moderate ME
PS 7-9: moderate/severe ME if requiring 50% reduction, or severe ME

If that is the case, then this study only used non-ME - mild ME patients since the worst they got on a bad day was PS 6 and could be as high as PS 2 on a good day. Not a representative sample. I consider myself in decent (not great) shape for a PWME and I'm 5/6 on a good day. But maybe my perception of "decent for a PWME" is skewed having come from PS 9.

The PS grading score was at least one higher on the “bad day” (PS: 3–6) than on the “good day” (PS: 2–5) for each patient.

It's clear this research is very relevant to chronic fatigue patients. I wonder how much it applies to ME patients. IMO, Julia Newton studies OI and/or chronic fatigue patients and conflates that with ME patients. Can someone who can access the full paper tell us what definition this research used to define ME patients?

PS 0 The patient can perform the usual activities of daily living and social activities without malaise.
PS 1 The patient often feels fatigue.
PS 2 The patient often needs to rest because of general malaise or fatigue.
PS 3 The patient cannot work or perform usual activities for a few days in a month.
PS 4 The patient cannot work or perform usual activities for a few days in a week.
PS 5 The patient cannot work or perform usual activities but can perform light work.
PS 6 The patient needs daily rest but can perform light work on a “good day”.
PS 7 The patient can take care of himself/herself but cannot perform usual duties.
PS 8 The patient needs help to take care of himself/ herself.
PS 9 The patient needs to rest the whole day and cannot take care of himself/herself without help.

ETA: I started a new thread here to discuss severity scales so that I don't take this thread too far OT.

 

[Sidereal]

Can someone who can access the full paper tell us what definition this research used to define ME patients?

This study used the ICC.

 

[SOC]

This study used the ICC.

Thanks!
I'm very pleased to see a researcher using the ICC for patient selection!

However.. given this statement from the ICC

Operational notes:For a diagnosis of ME, symptom severity must result in a significant reduction of a patient’s premorbid activity level.Mild(an approximate 50% reduction in pre-illness activity level),moderate(mostly housebound),severe(mostly bedridden) or very severe(totally bedridden and need help with basic functions).

how can patients who are at worst

PS 6 The patient needs daily rest but can perform light work on a “good day”.

and at best

PS 2 The patient often needs to rest because of general malaise or fatigue.

be considered to meet the ICC? It looks like some of their patient cohort don't meet the ICC even on a bad day since they're only unable to work a few days a month at their worst.

 

[Float]

The exaggerated sympathetic nervous activation is the key problem of this disease for a subgroup not all ME/CFS patiënts. This subgroup can be objectively indentified and must get another name. There symptoms are not subjective but can be measured by bloodflow problems, tachycardia etc... The one million dollar question is; what causes this overactivity? This is the central issue for POTS/ME. I think it is autoimmunity against Beta receptors and Alfa. This subgroup has an autonome vasculair disease.

How do you test for autoimmunity against Beta receptors and Alfa? I have had some improvement by using an alphaadrenergic agonist - but still get fatigued after overdoing it (the agonist helps me do more so therefore may be assiting the overdoung it!) Thanks!