Symptom variability following acute exercise in ME-CFS: a perspective on measuring PEM

[Dolphin]

http://www.tandfonline.com/doi/full/10.1080/21641846.2017.1321166

Symptom variability following acute exercise in myalgic encephalomyelitis/chronic fatigue syndrome: a perspective on measuring post-exertion malaise

Jacob B. Lindheimer a,b,c, Jacob D. Meyer c,d, Aaron J. Stegner b,c, Ryan J. Dougherty b,c, Stephanie M. Van Riper b,c, Morgan Shields c, Amanda Reisner c, Sanjay K. Shukla e, Alan R. Light f,g, Steven Yale h and Dane B. Cook a,b,c
aDepartment of Veterans Affairs, New Jersey Healthcare System, War Related Illness and Injury Study Center, East Orange, NJ, USA;
bDepartment of Veterans Affairs, William S. Middleton Memorial Hospital, Madison, WI, USA;
cDepartment of Kinesiology, University of Wisconsin-Madison, Madison, WI, USA;
dDepartment of Family Medicine and Community Health, University of Wisconsin-Madison, Madison, WI, USA; eMarshfield Clinic Research Foundation, Marshfield, WI, USA;
fDepartment of Anesthesiology, University of Utah, Salt Lake City, UT, USA;
gDepartment of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT, USA;
hMarshfield Clinic, Marshfield, WI, USA

ABSTRACT

Background:

Consensus for an operational definition of postexertion malaise (PEM) and which symptoms best characterize PEM has not been established and may be due to variability within and between studies.

Purpose:

Determine the magnitude of the effect of maximal and submaximal physical exertion on multiple myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) symptoms that are associated with PEM and explore variability among two studies in which mood, fatigue, and pain symptoms were measured before and after exercise.

Methods:

Symptoms were measured before, and 48 and 72 hours after exercise in study 1 (ME/CFS = 13; Controls = 11) and before and 24 hours after exercise in study 2 (ME/CFS = 15, Controls = 15).

Between-study variability was examined by comparing Hedges d effect sizes (95% CI) from studies 1 and 2. Within-patient group variability was examined via inspection of dot density plots.

Results:

In study 1, large increases in general fatigue (Δ = 1.05), reduced motivation (Δ = 0.93), feelings of fatigue (Δ = 0.90), feelings of confusion (Δ = 0.93), and total mood disturbance (Δ = 0.90) were found at 72 hours.

In study 2, a large increase in affective/sensory pain (Δ = 0.79) was found at 24 hours.

Dot density plots in both studies revealed substantial variability among people with ME/CFS relative to healthy control participants.

Conclusions:

PEM symptoms are variable among people with ME/ CFS and several gaps in the literature need to be addressed before guidelines for measuring PEM in the clinical or research setting can be established.

ARTICLE HISTORY

Received 9 December 2016
Accepted 11 April 2017

 

[Dolphin]

The participants were instructed to answer each questionnaire item in terms of how they felt at the time that the questionnaire was administered (i.e. ‘right now’).

 

[Dolphin]

Study 1: maximal exercise

11 healthy control participants matched for age and self-reported physical activity

 

[Dolphin]

There is supplemental data anyone can access for free here:
http://www.tandfonline.com/doi/suppl/10.1080/21641846.2017.1321166?scroll=top

 

[Dolphin]

The basic data is in Tables 2 & 4 and Figures 1 & 2

 

[Valentijn]

I wish they'd asked more about physical symptoms, and less about mood and fatigue.

 

[Dolphin]

The small sample sizes reduce the chances of getting statistically significant average differences. But still study shows that it can be hard to define the illness based on the subjective response to a single exercise test in individuals.

 

[Dolphin]

Data on the CDC symptoms is included in the supplemental files.

 

[Dolphin]

Vigor goes in the opposite direction i.e. more is better so changes are in the expected direction in both Table 2 and Table 4.

 

[Dolphin]

An examination of effect sizes and 95% confidence intervals indicated that fatigue, mood, and pain symptoms were not significantly different between people with ME/CFS and control participants 48 hours postexercise. However, people with ME/CFS reported large and significant changes in several indices of fatigue and mood at 72 hours postexercise.

Lamanca and colleagues matched people with ME/CFS and control participants for habitual physical activity and measured gene expression levels before and 24 hours after maximal exercise [19]. The investigators also measured fatigue symptoms with the Chalder Fatigue Scale [20] and reported a significant main effect of time for people with ME/CFS but not control participants at 24 hours postexercise. However, when the effect size calculation methods used here were applied to the symptom data reported by Lamanca et al., a moderate effect size for fatigue was found, but the confidence interval overlapped zero (Δ = 0.56; 95% CI: −0.14, 1.26). Thus, it appears that a measurement time period greater than 24 hours postexercise may be needed to capture significant differences between people with ME/CFS and control participants.

Other studies are also discussed

 

[slysaint]

Wish they'd stop using that blasted Chalder Fatigue scale.

 

[Dolphin]

Table 4. Study 2 Hedges’ d effect sizes and 95% confidence intervals at 24 hours postexercise.

Only one of the 18 changes is statistically significant different [MPQ = McGill Pain Questionnaire]. However all 18 are in the expected direction.

 

[trishrhymes]

I wish they'd asked more about physical symptoms, and less about mood and fatigue.

I've only read the abstract posted here, but that struck me too.

My PEM involves amplification of all my ME symptoms, pain, weakness, nausea, headaches, dizziness, generally feeling too ill to get out of bed, and brain fog, which for me really only impacts badly during PEM. Any mood change is a direct result of the symptoms, though being unable to think straight, being in acute pain all over, and hoping not to vomit kind of overrides any registering of finer points of mood.

I'm not sure I could have filled all that in on a questionnaire, the Chalder Fatigue Scale would evoke the sounds of paper ripping and me throwing up, not a serious attempt to fill in that pile of crap.

Edit - I really should read a whole paper before I comment.

 

[JaimeS]

Wish in general there would be less "ME is fatigue" going around.

 

[Seven7]

We should demand to measure lactate levels, Oxygen vs DO. Metabolites....
I mean sport science is not new, I don't understand why CFS is like just ask questions instead of using common sense testing.

 

[duncan]

This study may be limited in that it only attempts to parse down on overtly obvious physical exertion. Although this is clearly relevant and important, it seems to exclude other forms of exertion, including cognitive and emotional exertion.

We know that each of us is individual in which form of exertion triggers PEM. As many reservations as I have relative to the NIH ME/CFS study, I was pleased to see an exertional study in the form of a mathematics exercise.

Point being: different forms of exertion may be at play, and to research differently may risk excluding ME/CFS subgroups.

 

[Dolphin]

Wish they'd stop using that blasted Chalder Fatigue scale.

Just to be clear to anyone reading this: the Chalder fatigue scale wasn't used in this study, just in one it discusses.

 

[Dolphin]

We should demand to measure lactate levels, Oxygen vs DO. Metabolites....
I mean sport science is not new, I don't understand why CFS is like just ask questions instead of using common sense testing.

Other things were measured in study two just not discussed in this paper. This paper is one that discusses that

[24] Cook DB, Light AR, Light KC, et al. Neural consequences of post-exertion malaise in myalgic encephalomyelitis/chronic fatigue syndrome. Brain Behav Immun. 2017;62:87–99.

I think there are others also.

 

[hixxy]

Any mood change is a direct result of the symptoms, though being unable to think straight, being in acute pain all over, and hoping not to vomit kind of overrides any registering of finer points of mood.

My mood can alter drastically when I crash and not just because I'm unhappy about the crash and symptoms. I get lowered mood, OCD like behaviours with frustration, agitation, anxiety, insomnia and a lot of neuro sensory problems. I also get a lot of worsening of physical symptoms too.

 

[Murph]

1. I like this approach. We all know me/cfs patients can appear normal-ish when rested (especially the mild/moderates who are likely to sign up for studies). Attempts to measure PEM are the future of research!

2. The problem seems to be that these patients are broken even before the exercise and we don't see much of an effect from it.

3. While it is not prominent in the abstract they did enquire about physical symptoms.

I like the dot plots - much more transparent than just measures of means and standard deviations. But I still wish they'd mark p values on the charts so we can see if any of this might be more than just random.