Discussion in 'Phoenix Rising Articles' started by Mark, Jul 29, 2013.
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This is a start!!! Albeit not one any of us were expecting, but woohoo!! It really is a start, and if they can identify sub groups, and then correlate with the subgroups, we could very well get confirmatory results, and testing, and legalities tied down, and finally, some type of healthcare, oh...and the very least, a howdy doo.
Simon -- another excellent article.
Thank you Simon for your clear presentation of this study. It is apparent that this two day test can be beneficial for those who are building a case for the diagnosis of me/cfs but, does this mean that if one does not show a positive outcome of this test, that they do not qualify for a diagnosis of me/cfs. Does this back up the need of the ccc or Icc criteria having the mandatory symptom of pem/pene?
Great article, Simon!
Great article, Simon - this is very important research.
I have a concern, though, about its wide use as a diagnostic tool and that's whether the test itself could provoke a relapse. Do the authors have anything to say about this in their paper, or any follow-up data?
The results of this study showed that it should detect 90% of CFS cases, or 10% of Fukuda-defined CFS cases would be missed. They didn't assess patients according to other criteria so it doesn't say anything about CCC and ICC - both of these require self-reported symptoms eg post-exertional malaise, rather than objective markers of exercise dysfunction. It would have been interesting to see follow-up symptomatic data for this study, as well as the objective data, to see how well the two correlated.
That's a very important point, and no, it wasn't addressed in the paper. A number of people who have undertaken the test have reported they recovered without any permanent deterioration, including Lannie and Jennie Spotilla, but I do think that if the test is to be widely used there needs to be systemmatic data on the likely impact on patients, both post-exertional symptoms and any relapses.
Thanks Valentijn, Kina
Thanks, Simon. I'm trying to familiarise myself with this and foggy brains need repeated readings for it to sink in.
Could you clarify for foggy brains what VO2 is, please? I know that VT02 is the ventilatory threshold, but VO2?
I think the repeat exercise testing is some of the most important research that has ever appeared into ME. Until we have something better I think this should be considered the Gold Standard in ME functionality testing, although I do thing we need studies showing it works in CCC and ICC defined cases to address possible criticism.
This does exclude more severe patients though. If this research can be advanced and other markers found as a result, then testing on bedbound patients might become possible ... but for now it isn't.
"The authors suggest that a synergy of small effects across multiple systems could be responsible for the poor exercise performance of the individuals with CFS." I think this statement is critical. Its looking increasingly likely that well defined CFS is a heterogenous collection of different problems. Traditional medicine has looked at single-cause disease. For a heart to not supply sufficient blood for everyday use, for example, it must have seriously degraded capacity. I have been asking a question for some years now: what happens if you lose much less capacity, say 10 to 20% in many interacting systems? Rather than failure at one critical point, its the entire system that would be degraded, and testing each individual part would show up as normal.
Consider a chain of things A to D. (This could be mitochondria, muscle function, heart function, circulation function for example.) Now suppose heart function is down 60%, then the circulation output would be down 60% as its on the critical path. Consider however if all of them were down by just 20% each, which might not be considered normal. What is the outcome? (0.8)^4 = approx 41% capacity. This is almost the same as a 60% fall in heart function, if measured over the entire chain of mechanisms.
It would be interesting to do immune system testing at the same time prior to tests, after first test, after second test and after different recovery times.
Also I was wondering how this fits in with Julia Newtons work looking at lactic acid in muscle tissue. I was thinking this may relate to the VT02 threshold
That was done by the Drs Light, wasn't it? And showed huge effects in PWME vs healthy & MS controls. Was that immune stuff or endocrine & other stuff?
Sorry, thought I'd explained CPET well, but omitted the most important bit of info (would like to blame my illness for this but don't think that's the case).
VO2 is Volume of Oygen consumed.
VO2 plain and simple is measured in litres, but as VO2 depends so much on a person's size, it's usually expressed as mls O2, per minute, per kilo of body mass. For example, in this study the VO2 peak (volume of oxugen consumed) was 21.5 ml O2/min/kig - which is very low.
So VO2 max, VO2 peak and VTO2 are all volume of oxygen consumed per minute per kilo of body mass, at maximum, peak and ventilatory threshold. VTO2 is probably better called VO2 VT, but VTO2 is often used instead.
I think the former is being done by Nancy Klimas, though I suspect she only uses a single maximal test. As Sasha notes the Lights looked at immune markers - or rather mRNA of immune marker proteins and found a small difference in CFS for the CD4 protein mRNA. They used a single 'moderate' exercise protocol, rather than a maximal one (though was probably close to maximal for the most severely affected patients they used,and these patients accounted for most of the effect seen).
Interesting idea about Julia Newton's lactic acid test, though her group didn't use a maximal test, and didn't use a repeat test either. The Snell study here didn't find a difference in VT for the first test, only on the repeated test.
Mostly it was looking at mRNA expression of adrenergic nerve pain/fatigue receptors where the effects were much bigger than the CD4 (immune marker) difference they found.
Having been ill for nearly 11years, it can now take up to a week before PEM hits me. It laso lasts for a lot longer (for the same amount of overdoing) than it did earlier on.
I'm not sure testing just one day after (on myself) would actually show anything (apart from reaching the lactic acid thing far too soon and not being able to get into aerobic metabolism at all, which is what shows on the first testing anyway.)
I would be really interested in seeing exercise testing done even later - and then some more to see how long it lasts for.
And to have that related to the length of time the subject has beeen ill.
I don't think I'm the only person who has found this peculiarity.
Thank-you, Simon for reporting this great bit of research.
It really is incredibly hopeful to, finally, see the right things being looked for and tested.
I wish I could be tested. In the cold below 12 deg C I can repeat more or less the same test again and again for a couple of weeks, and do similar average miles for average heart rates, in fact I can see gains in mileage and lower heart rates.
Simon. Another cracker and very nicely presented on the full version I must say. Loved the cartoon
I couldn't get my head round this paper so thank you for persevering. Kind of what makes this place so great. If I can't figure it out then chances are someone else can
Having just returned from hospital and spoken with some physiologist science boffin about my 'mass of data' it would appear that initial suggestions are that my poor brain cell is being starved of oxygen during the night. It's too soon to say 'apnea' but we talked a bit around the topic; and I am left wondering to what degree oxygen starvation generally could be responsible for my muscle problems also (and lack of energy too I suppose) during the night and during the day.
It seems that oxygen is tied up with much that might be wrong. If my cells are not getting the oxygen they need then, as you said above, the outcome is more lactic acid and pain and discomfort for me. An inability to operate my muscles or for my muscles to recover from exertion. But above looks at inability to recover from exercise; and not ability to exercise in the first place - I am wondering then if those controls were experiencing the degree of muscle pain and ache etc. that I do constantly. Maybe this is where Prof. Newton's work comes into focus. Are 'we' just not getting enough oxygen, or not processing it, or not being able to process it?
All good stuff old bean
Beautifully clear, thanks, Simon!
I find that PEM takes longer to appear when I am relatively well, and at best it becomes almost imperceptible. Before I started getting these improved phases, my PEM occurred 2 days after exertion, almost like clockwork.
The fact that further exertion seems to put the PEM on hold, and that it then comes back with a vengeance, makes me extremely curious to know what is happening physiologically.
Answers to such questions could be invaluable.
Interesting point about the variability in PEM: mine doesn't even wait for 24 hours before it hits but clearly for others, including yourselves, it takes much longer, and that could complicate things.
Without changing their setup much, it would be interesting to ask patients how long before their PEM typically occurs, and correlate that with changes seen between test 1 & 2. They already have illness duration data, so could include that in the analysis too. (I don't know if they have looked at that separately).
This study do not proof PEM post-exertional malaise but post-exertional fatigue! Read the abstract correctly. Verry important finding.
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