Maximal handgrip strength can predict maximal physical performance in patients with chronic fatigue, 2020, Jammes et al

Paywall, https://www.clinbiomech.com/article/S0268-0033(19)30701-6/
Sci hub, https://sci-hub.se/10.1016/j.clinbiomech.2020.01.003

@PhysiosforME , one of interest to you?

 

Interesting. I think we need more research into commonplace devices which can be used to assess symptoms.

They don't have to be biomarkers, but if we have tests that corroborate symptoms like fatigue, cognitive dysfunction and loss of function on repetition of effort, it'll make it easier to a) diagnose patients and b) take them seriously.

 

The 'Chronic Fatigue' participants:

I still don't quite know what the relevance of an estimate of maximal exercise performance is in ME or CFS patients though.

The (combined) correlation coefficient for right handgrip and left handgrip strength predicting maximal workrate was R=0.725, 0.767 and 0.463, 0.509 for VO2Peak.

So there clearly is an association but it is not a very strong association overall. Interestingly, the workrate data is discrete/stepped and you might expect this to reduce the correlation coefficient, yet it was higher for workrate than VO2Peak (which was continuously measured). Also interestingly, the left handgrip strength predicted peak workrate in ME/CFS patients more strongly, with R=0.86.

 

"Proof" of illness, in this case without having to be pushed to the level used in a CPET?

 

But maximal exercise performance on a single CPET has little to do with proving illness, simply lack of fitness or motivation.

 

Some people have still used the one-day CPET to prove functional impairment in disability cases, etc. It almost doesn't matter what the cause is or whether it's reversible; it's still an objective measure of current functioning.

 

I'm not so sure about this, perhaps I've got the wrong end of the stick?

I have always had very strong hands and I'm not sure that my level of function would be accurately assessed by this.

Although I am a small female I was always very strong for my size. Surprisingly so. Probably to do with a lot of the sports and activities I was involved in as a youngster.

Throughout my career I have had to lug heavy kit about and dismantle and reassemble kit. All of my colleagues are male and many of them seemed to think twisting a screw to "hand tight" meant twist it as hard as you could by hand. So in my early years of illness I still had a grip that was easily as strong as some men.

Over 20 years in I have lost a lot of that strength through disuse, but even sick my grip is probably as strong as my sister's was at my age. She's the family weakling.

So perhaps I am being a bit slow here but -
Some people will have much stronger grip than others due to natural variance, jobs and hobbies. Length of illness and severity of illness will also affect strength at time of measurement.

I can see that the fatigability of hand muscles in terms of grip and strength might tell you something helpful, but not strength alone.

 

Indeed, and it's pretty useless as an indicator if you also have arthritis...

 

Possibly worth noting that grip strength, like HRV, isn't a static value and can depend on fluctuating factors. E.g. if you have a cold coming on, your grip strength will decrease. That can act as an early warning system for athletes that they need to take it easy for a few days, because they're not at peak health. "Not at peak health" is pretty much the definition of an ME patient.

I'm not really sure where the authors are going with this study, but if it's something like using grip strength as a proxy for CPET performance so that patients don't have to undergo a potentially ruinous exercise test, then maybe that's not a bad thing.

 

I understand that some people who don't understand what it measures may consider it evidence, but well, the fact remains that the (average) peak workrate and VO2Peak found in this study are still more than sufficient to do most jobs.

 

Define 'sufficient to do most jobs'. Who decides that? If a person displays only 60% of the strength of an average person of their age, then that may be significant. If it's 80%, maybe not.

The other reason you might want to do this is to assess whether the person is capable of doing a two-day CPET in the first place. If they score very poorly, you might decide not to do one at all.

In general, I'm for measurable things, whatever they are, for patients. Obviously there's still a lot of work to do here, and no one here is saying this is a biomarker, but the less we have to rely on 'subjective report', the more we can move away from a condition measured (in clinicians' eyes) solely by questionnaires.

 

I'd suggest we already know that before they do the handgrip test too, mostly-bedbound patients are too ill to do CPETs...

Many jobs (office jobs and many, but not all service industries) these days do not rely on high strength or high aerobic performance.

 

In ME, the important measure is how quickly performance deteriorates. No one seems to look at that properly but it is the crucial thing that I believe defines ME as opposed to other fatiguing illnesses. It is neglected because of the perception we are deconditioned.

When I was first diagnosed in the 80s, one of the doctors would get patients to write by hand a description of their problem while they sat in the waiting room. The change from the first sentence to the last he felt was a good indication of ME. It is the change that is important.

It is possible to be reasonably fit with ME but even then performance drops.

People have often said how they can play a game on the computer but after a while they get worse and worse. Healthy people get better as they practice. It wouldn't be that difficult to set up a test. The advantage over hand grip strength is that people with severer disease could still do it.

 

https://www.s4me.info/threads/hand-...l-biomarker-for-me-cfs-2018-nacul-et-al.6612/

This previous thread has various posts describing the use of the Hand Grip Test undertaken by all participants in research studies at Cure ME: U.K. ME/CFS Biobank.

Note the same test is carried out at the identical point in the meeting for all patients, whether Severe, Serious or Moderate. Only once (out of 3 so far) has my 2nd grip been a little more than my 1st and my 3rd has always dropped, despite hard gripping.

 

But not all patients are bedbound. I think you're being either pedantic or contrary, but I'm trying to give you the benefit of the doubt here.

Obviously it's an abstraction. But many OTs use it as a measure of general stamina and physical capacity. I doubt anyone is suggesting to use this in isolation.

It's much harder to do a service job (which may require lots of running around) with reduced physical function. Likewise, even working in an office can be strenuous if you have a low physical capacity, even if it's not overtly physical. As pwME, we know this.

And I'll say it again: not having to measure this illness entirely by questionnaire is potentially a good thing.