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

I, too, think handwriting would be a good thing to assess. It's used in Parkinson's and other diseases. It would be useful, I think, to develop a way to separate ME from other illnesses that affect handwriting.

 

Which is a mistaken assumption when it comes to ME and CFS patients. The whole point is that our stamina is not merely limited by our VO2peak or (maximum voluntary) handgrip strength. Despite what some small minded neurologists believe, fatigue is not merely a reflection of low strength or aerobic performance!

Now someone might say, well why not measure decline in handgrip over time for a day or two? The problem is there is no control for effort, so doctors will just blame it on lack of effort or 'central fatigue'. The robust alternative is to measure effort and motor unit recruitment patterns at different effort levels using EEG and EMG with a more sophisticated graded strength test, but in doing so, we've turned a simple test into a complex one.

 

There's at least some evidence that it's hard to 'fake' hand-grip strength tests. I linked to that in the repeat hand-grip strength test thread when that same issue was raised.

I've tried it myself a few times. It's harder than you think to consistently apply less pressure. The results would be all over the place.

Furthermore, such tests aren't considered evidence of lack of motivation in other patient groups. It's just one of a handful of tests that can be done to get a better picture.

Consider which gives a worse impression: a patient who reports extremely debilitating symptoms, despite looking well, and without any way to verify their symptoms; and someone who looks well but actually shows some abnormalities on one or two routine tests?

Of course there will be outliers. There always are. Clinicians expect this.

 

There's an interesting article on the NHS "Behind the Headlines" blog on a different study that attempted to use grip strength to make predictions about mortality rate from cardiovascular disease. It's from 2015.

It's quite sceptical of the study claims, and covers some of the points made in this thread. It doesn't toss the idea out entirely, though: https://www.nhs.uk/news/heart-and-lungs/could-testing-grip-strength-predict-heart-disease-risk/

 

I don't think you quite understand, I was not implying that people would deliberately apply less pressure.

My question is what does this test reveal with either high sensitivity and or specificity (compared to other illnesses) that we didn't already know?

 

And that's fair enough, I think. You can recognise the utility of a test (dynamometers are in every GP's surgery) while still acknowledging that it's limited.

 

Yes, it is of interest - I have already skim read it and shared with the other three. More in depth read planned for this weekend!
Thank you

 

Oh, I see. I don't think it really adds anything new in that sense. It's not supposed to be a biomarker. You would probably use this as a 'supportive' test.

E.g., patient reports weakness that wasn't there before. HGS test shows weakness. Clinician believes patient.

That sort of thing. It's definitely not something that would prove anything specific to ME; just general weakness/fitness/functional capacity.

 

I can see some benefit to that, but the issue around the fluctuations in ME might result in a misleading entry on the patient's notes. I usually wait until I am well enough to go to the GP, so they will see me at optimum performance, fatigability being variable in my case.

The better my cognitive function the more successful my appointment so, in addition to being in a good patch, I will have rested up for days beforehand. Which means I will have used my hands less than I usually would and that will further reduce fatigability.

As a one off, it doesn't reflect reality. Like the CPET tests over consecutive days would give a more accurate picture. In my own case at any rate.

 

But surely you'd flag that before the test, though? It would obviously require some commonsense.

Additionally, if it was used in the early days, before diagnosis, would you be pacing at that point? You'd probably be more likely to be unwell at that stage anyway.

Likewise, you wouldn't test blood sugar after a big meal. It's usually done after fasting. We just need a set of guidelines for how to get the best result (and it might be the Biobank's repeat test in order to trigger fatigue).

 

It depends on how this test would be used @adambeyoncelowe.

Quite right in terms if pacing, but I would have been initially stronger and possibly with less fatigability. I have become worse over time going from moderate to severe.

Well, I would now but in the earlier years I wouldn't know to. So if the GP, or whoever didn't realize it's not just about fatigability, but also PEM then it might not be taken into account.

As for common sense - doctors who don't understand ME think telling people to exercise a bit more is common sense.

Don't get me wrong, it would be great to have something other than a questionnaire but the years have made me cynical. I have learned that what is said about me can be used against me along with what I say.

The ESA form specifically asks about using the hands. So, unless this test really does accurately reflect how ME affects handgrip and the ability to use the hands as I truthfully report in my ESA form, could the recorded result of the test be used against me? As this is a question that's asked I worry about the consequences of it not being carried out in a way that accurately reflects reality.

 

I understand where you're coming from. We've been burned pretty badly. But we shouldn't solely focus scientific efforts on ways to avoid bad-faith actors, because someone who's acting in bad faith is going to do so whatever happens.

Even objective tests can be misused by the wrong people. Or they'll make up excuses to deny it means what we say it means.

But if we never allow any tests to be developed for our condition because they might be misused, the irony is that we'll stay in that vague, 'contentious' area where we're never believed anyway.

In the meantime, we need to find ways to measure this disease, even if they're not perfect. It's an incremental process.

 

I agree @adambeyoncelowe, I'm not trying to throw spanners into the works for the sake of it.

I am concerned we ensure that any test carried out is testing what we think it's testing and does it as accurately as possible.

That there is some way of ensuring it is carried out properly - who would be carrying out the test GP, specialist? How can we hold them to account if it isn't carried out correctly.

All the more important as this is a specific question by the DWP and so many of us have had to fight so hard as it is.

What advantage would this test give us over the status quo? If the answer is nothing much and there are risks of it being used against us then that's an issue.

 

Yes, I get you. I think the Biobank test is targeted at GPs and nurses.

The DWP do tests like this anyway but without any evidence base. However, you can decline to do any tests during PIP assessment or WCAs, in which case, the assessor has to rely on your medical records.

 

erm....

In my experience if you decline to do a test, on any basis, they simply say it was completed without issue, and when challenged, they, the DWP, and a tribunal, simply state that someone trained specifically, and paid, to provide 'justification' to refuse or minimise a claim couldn't possibly be lying so as to refuse/minimise a claim.

 

Liars will lie whatever you do.

 

Sorry can't seem to cut and paste from the document itself.

Within the document it states the test doesn't distinguish patients with chronic fatigue from those with chronic fatigue syndrome.

The test is a single event - 3 maximal grip tests held for 5 seconds with the strongest grip being used for the reading.

It isn't going to give any indication of the effect of PEM on a patient.

It really depends how this test would be used - as a diagnostic tool - can't distinguish between chronic fatigue and ME or CFS so not great.

In research carried out before and after an intervention as a measure of efficacy - maybe, but ME is fluctuating plus PEM might be a confounding factor.

If it's used as a screening tool for patients needing to undergo an exercise test I can see the benefit there.

 

I'm surprised these were correlated. I was recently a sedentary control in a US 2 day CPET study and my anaerobic threshold was extremely low - placed me near the bottom category for my age group. And yet, I can easily walk at a pace of 3.5-4 miles per hour for 6 minutes and my hand grip is strong. Maybe I am not understanding how the 6 minute test is done.

 

Is it that surprising though? In the aforementioned study, grip strength only explained around 50% of the variance of VO2peak, it was maximal workrate that had a higher R squared of around 0.7.

Not everyone ends up pushing their cardiopulmonary limits while doing the 6MWD.
Energy expenditure vs speed is examined here (1973 study):
https://www.physiology.org/doi/abs/10.1152/jappl.1973.34.5.559
(too long didn't read: VO2 = 0.00599M + 0.000366MV^2 where M=mass, V=speed in km, VO2 in L/min)

In my case, the VO2 during my 6MWD is estimated to be around 74% of my VO2Peak. (~850m, 44 ml/min/kg a few years ago)

There has been an attempt to predict peak VO2 from 6MWD, but is subject to large variance, it might be interesting to see whether the equation predicts your VO2Peak: https://bmcpulmmed.biomedcentral.com/articles/10.1186/1471-2466-10-31
For me, their equation only predicts a VO2Max of only 55% of my measured VO2Peak. So my 6MWD must be limited by something other than my cardiopulmonary limits (eg muscle fatigue!), or these equations are wrong.

 

I just posted something along these lines on a different thread, not knowing this was here!

https://www.s4me.info/threads/physios-for-me.10741/page-9