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Submaximal exercise testing with near-infrared spectroscopy in Myalgic Encephalomyelitis/CFS

ahimsa

ahimsa_pdx on twitter
Messages
1,921
Has this study been posted yet? Any comments?

Link - http://link.springer.com/article/10.1186/s12967-015-0527-8

Submaximal exercise testing with near-infrared spectroscopy in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome patients compared to healthy controls: a case–control study

Ruth R Miller, W Darlene Reid, Andre Mattman, Cristiane Yamabayashi, Theodore Steiner, Shoshana Parker, Jennifer Gardy, Patrick Tang, David M Patrick

Abstract

Background

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating illness. Symptoms include profound fatigue and distinctive post-exertional malaise (PEM). We asked whether a submaximal exercise test would prove useful for identifying different patterns of tissue oxygen utilization in individuals with ME/CFS versus healthy subjects. Such a test has potential to aid with ME/CFS diagnosis, or to characterize patients’ illness.

Methods

A case–control study of 16 patients with ME/CFS compared to 16 healthy controls completing a 3-min handgrip protocol was performed. Response was measured using near-infrared spectroscopy, resulting in measurements of oxygenated (O2Hb) and deoxygenated hemoglobin (HHb) over wrist extensors and flexors. Changes in O2Hb (delta (d)O2Hb) and HHb (dHHb) absorbance between the first and last contraction were calculated, as were the force–time product of all contractions, measured as tension-time index (TTI), and ratings of perceived exertion (RPE).

Results

Individuals with ME/CFS demonstrated smaller dO2Hb and dHHb than controls. However, after adjusting for TTI and change in total hemoglobin (delta (d)tHb), differences in dO2Hb and dHHb were reduced, with large overlapping variances. RPE was significantly higher for cases than controls, particularly at rest.

Conclusions

Relative to controls, participants with ME/CFS demonstrated higher RPE, lower TTI, and reduced dO2Hb and dHHb during repetitive handgrip exercise, although considerable variance was observed. With further study, submaximal exercise testing may prove useful for stratifying patients with a lower propensity for inducing PEM, and have the ability to establish baseline intensities for exercise prescription.
 

SOC

Senior Member
Messages
7,849
Do I read the paper correctly that 1/16 (6.3%) of patients, but 4/16 (25%) of so-called healthy controls had orthostatic intolerance? I wonder if that would affect the results in any way?

ETA: In the text, it says this:
Finally we hypothesized that lower TTI may be related to dysautonomia in ME/CFS patients, which we investigated through orthostatic intolerance. Since only four ME/CFS patients had orthostatic intolerance, statistical significance was not achieved (P = 0.1), but it was notable that ME/CFS cases with orthostatic intolerance had lower median values for TTI (8,778 vs. 11,436 Newtonseconds) and two of the four ME/CFS individuals with orthostatic intolerance had the two lowest TTI values seen in the study.
my bolding
I wonder if Table 1 Characteristics of study participants is in error wrt which group had orthostatic intolerance.
 

SOC

Senior Member
Messages
7,849
I was thoroughly unimpressed with this bit
An alternative explanation for the lower TTI is reduced redistribution of cardiovascular output to exercising muscles resultant from impairment or lack of fitness in ME/CFS patients. Reduced fitness may result from patients with ME/CFS’s aversion to physical activity due to fear of fatigue. This aversion increasingly perpetuates deconditioning, similar to the pain catastrophizing theory.
:mad::grumpy:
 

Kati

Patient in training
Messages
5,497
Do I read the paper correctly that 1/16 (6.3%) of patients, but 4/16 (25%) of so-called healthy controls had orthostatic intolerance? I wonder if that would affect the results in any way?

ETA: In the text, it says this:
my bolding
I wonder if Table 1 Characteristics of study participants is in error wrt which group had orthostatic intolerance.
i am also surprised by the number but one needs to put things in perspective. The subjects are from the Vancouver area and there are no real access to tilt table testing, or physicians willing to do a poor man test accurate enough. I think it is a bias, but I could be wrong.
 

Kati

Patient in training
Messages
5,497
With Dr Peterson and Staci Stevens coming to speak in Vancouver on Sunday, it will be interesting to see who will be attending. How many drs and academics.

On a side note, many of the authors of this paper are collaborating in a 2consecutive days exercise test for gene expression.
 

SOC

Senior Member
Messages
7,849
i am also surprised by the number but one needs to put things in perspective. The subjects are from the Vancouver area and there are no real access to tilt table testing, or physicians willing to do a poor man test accurate enough. I think it is a bias, but I could be wrong.
But then why so many healthy controls with OI, but hardly any PWME? With no access to TTT, you'd think no one would be diagnosed with OI and certainly not healthy people.

I think they must have messed up their table. It has to be that 4/16 of PWME were diagnosed with OI and 1/16 HCs had OI.
 

Kati

Patient in training
Messages
5,497
Early on in my disease, my insurance company sent me for a 2days physio assessment. One of the test was a grip test. Interrestingly enough, doinig a maximal grip test was hurting me deep in the brain after the effort. The physio thought I was deconditioned and didn't consider this particular symptom as being significant.
 

user9876

Senior Member
Messages
4,556
A general point is that although they talk about PEM they measure immediate effects (or thats what they talk about in the abstract) so this may have little to do with PEM if it is caused by a signalling mechanism or a cascade of signals. So I don't think there conclusions about inducing PEM are very good.

However, looking at oxygen flow seems interesting in that it might help fill in one piece in a much bigger puzzle.

Looking at figure 2 I would discount any results where they quote the mean for the CFS group since they have a significant outlier and a small population. The problem is the outlier will have a very significant effect on the overall mean. But they have shown graphs of individual data which is great and they are not quoting the mean or associated tests in there abstract.
 

SOC

Senior Member
Messages
7,849
Reduced fitness may result from patients with ME/CFS’s aversion to physical activity due to fear of fatigue.
Shall we have a poll? Who is afraid of fatigue? Not me.

Seriously, afraid of fatigue? There is so much wrong with that statement. First is the notion that we have an irrational fear of fatigue. I have never had any fear of fatigue. I'm not cowering in a corner. I pace appropriately to avoid PEM. There is no fear involved.

Second is the idea that if we are concerned about something that it's fatigue. I'm not concerned about a bit of fatigue. I am concerned about a months- or years-long complete crash in my health. That crash is not simple fatigue. Far from it. Anyone who knows anything about ME/CFS knows a major crash is not simply fatigue.

Third is the statement that we have an aversion to physical activity. That's silly. Most of us are as physically active as we can be. Our physical activity involves as much of our activities of daily living as we can manage without PEM. Some of us can work. Some of us can walk reasonable amounts. Many of us do more physical activity than is safe for avoiding PEM. We don't have an aversion to physical activity. If any of us have an aversion, it's to aerobic exercise, which is demonstrated to be harmful to us.

And then there's the bits about deconditioning and catastrophizing. I challenge the writer of that drivel to show me proof.

Where do they get this crap? Do they just pull it out of their....? Okay, I know where they get it. Sigh... The paper was looking pretty good for a while and then they come up with that garbage out of nowhere. Why?

On a side note, many of the authors of this paper are collaborating in a 2consecutive days exercise test for gene expression.
I don't know whether to think this is good or a bad. On one hand, they might learn something about the reality of exercise for PWME. On the other hand, their personal biases might cause them to misinterpret the data to our disadvantage.
 
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Kyla

ᴀɴɴɪᴇ ɢꜱᴀᴍᴩᴇʟ
Messages
721
Location
Canada
Ugh.

What's extra frustrating is this whole debate could be avoided if they would just use sedentary controls!
I guess it's much easier to just regurgitate that it is deconditioning than to actually rule that out with proper methodology.
 
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Kati

Patient in training
Messages
5,497
I don't know whether to think this is good or a bad. On one hand, they might learn something about the reality of exercise for PWME. On the other hand, their personal biases might cause them to misinterpret the data to our disadvantage.

Actually Staci Stevens is one of the co-investigators.
 
Messages
13,774
Reduced fitness may result from patients with ME/CFS’s aversion to physical activity due to fear of fatigue. This aversion increasingly perpetuates deconditioning, similar to the pain catastrophizing theory.

Given the poor research that's slipped into the literature on this stuff, it's not surprising to have it mentioned here.

It would have been nice for them to have used decondtioned/ill health controls.
 
Messages
1
Thanks for the opinions and views. I think you are right that the wording can be read as dismissive, and that's not the intention. We'll be more sensitive to such issues as we work more in the field. We're working in this area because we want to contribute to finding the causes of a debilitating illness. Every person who has contributed to the study comes with a story that makes me convinced that there is something yet to be discovered. Please stay tuned as we work through the sequencing data which will tell us more about the role of gene expression and of microbial agents. What we hope people get out of the study is that the sub-maximal exercise testing approach has not proved too useful. That's why we're working with maximal exercise testing to learn more about gene expression associated with post-exertional malaise. You may also be reassured that our further work on full exercise testing uses healthy but deconditioned controls. This kind of feedback is a helpful reminder of why we got engaged in the first place. My best. David Patrick, MD, FRCPC, MHSc
 

*GG*

senior member
Messages
6,389
Location
Concord, NH
Thanks for the opinions and views. I think you are right that the wording can be read as dismissive, and that's not the intention. We'll be more sensitive to such issues as we work more in the field.

We're working in this area because we want to contribute to finding the causes of a debilitating illness. Every person who has contributed to the study comes with a story that makes me convinced that there is something yet to be discovered.

Please stay tuned as we work through the sequencing data which will tell us more about the role of gene expression and of microbial agents. What we hope people get out of the study is that the sub-maximal exercise testing approach has not proved too useful.

That's why we're working with maximal exercise testing to learn more about gene expression associated with post-exertional malaise. You may also be reassured that our further work on full exercise testing uses healthy but deconditioned controls.

This kind of feedback is a helpful reminder of why we got engaged in the first place. My best. David Patrick, MD, FRCPC, MHSc

Thanks for your comments, breaking this up to make it easier to read :)

GG
 
Messages
13,774
This kind of feedback is a helpful reminder of why we got engaged in the first place.

Thanks for taking a bit of patient criticism well David.

re aversion/fear-anxiety, etc in CFS: Some letters critical of the PACE team's claims about this were recently published, and I posted them to this thread:

http://forums.phoenixrising.me/inde...er-and-non-response-response-from-pace.36651/

The PACE team weren't quite so open to criticism (their response also posted).
 
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SDSue

Southeast
Messages
1,066
Thanks for the opinions and views. I think you are right that the wording can be read as dismissive, and that's not the intention. We'll be more sensitive to such issues as we work more in the field. We're working in this area because we want to contribute to finding the causes of a debilitating illness. Every person who has contributed to the study comes with a story that makes me convinced that there is something yet to be discovered. Please stay tuned as we work through the sequencing data which will tell us more about the role of gene expression and of microbial agents. What we hope people get out of the study is that the sub-maximal exercise testing approach has not proved too useful. That's why we're working with maximal exercise testing to learn more about gene expression associated with post-exertional malaise. You may also be reassured that our further work on full exercise testing uses healthy but deconditioned controls. This kind of feedback is a helpful reminder of why we got engaged in the first place. My best. David Patrick, MD, FRCPC, MHSc

Thank you for your willingness to pursue answers to the devastating disease that is ME/CFS. You will find Phoenix Rising an intelligent and passionate group. As you know from working with ME/CFS patients, our passion is born of enduring enormous losses in our lives while being maligned, misdiagnosed, misunderstood, and sometimes even abused.

Welcome to the party. :balloons: We’re glad you came.

As @ggingues suggested (and gave a great example) please break future posts into small sections with lots of white space - many of us can no longer read paragraphs because of visual processing difficulties secondary to our disease. Thank you.
 

Battery Muncher

Senior Member
Messages
620
Thanks for the opinions and views. I think you are right that the wording can be read as dismissive, and that's not the intention. We'll be more sensitive to such issues as we work more in the field. We're working in this area because we want to contribute to finding the causes of a debilitating illness. Every person who has contributed to the study comes with a story that makes me convinced that there is something yet to be discovered. Please stay tuned as we work through the sequencing data which will tell us more about the role of gene expression and of microbial agents. What we hope people get out of the study is that the sub-maximal exercise testing approach has not proved too useful. That's why we're working with maximal exercise testing to learn more about gene expression associated with post-exertional malaise. You may also be reassured that our further work on full exercise testing uses healthy but deconditioned controls. This kind of feedback is a helpful reminder of why we got engaged in the first place. My best. David Patrick, MD, FRCPC, MHSc

Welcome to the forum, David. Thank you for your open-mindedness, and willingness to research this heavily neglected disease.