Hand grip strength as a clinical biomarker for ME/CFS, 2018, Nacul et al

If the BPSers query the reliability of the objective measures, it immediately brings into question the reliability of ALL their subjective measures.

 

Firstly a personal anecdote is my PE teacher had one of these devices, I was the strongest in my class on this HGS test (pre ME). It was useful for me because I’m not aggressive in my personality but the tougher girls saw my HGS score and were “oh we better treat you with more respect!”

Ah I wonder if we could get false asthma readings due to this muscle effect? I get asthma readings with peak flow but it’s unusual that I need an inhaler.

If this study was replicated I’d be interested in the same participants also doing the short exercise test that looks for myasthenia gravis. This is an electrophysiology test, not so easily available but very similar in terms of what the patient does (when I did it I think I moved my thumb a few times). EMG muscle testing and also the longer exercise test for Periodic Paralysis (also often triggered by exertion) could be done too while they have that equipment out.

I think this would be interesting to compare because these tests are sort of similar but testing specific things. Eg based on my lived experience I expect my HGS would be as described in this study now, my muscle function was abnormal on an EMG test (like myositis or possibly myopathy though I don’t have those labels), but on the same day the short exercise test was fine (it’s not nerve/ neuromuscular junction for me).

 

@Jonathan Edwards might know if this has already been done? There was a Richard Edwards (unrelated) who did muscle testing in the 80s, I think.

 

That'll be the one from Liverpool I suspect. He was more interested in muscular dystrophy than ME. He was also the one who dxd a friend of mine with ME when later (private scan) it was found she had MS. I went for an interview for a job in his lab when I was looking for work after time off with my kids. Glad I didn't get it!

 

Also previously discussed here (or the other place) most (all?) of us who’ve had genetic testing seem to have a tendency to fast twitch rather than slow twitch muscle fibres - good for sprinting but not marathons. Are we experiencing an extreme downside to this?

https://ghr.nlm.nih.gov/primer/traits/athleticperformance

 

The grip strength test that I was given was done using "Jamar hydraulic dynamometer". It had five settings and the setting was changed after each test. It says in the report that ! was the closest so I guess something gets moved further away and the test becomes harder (or easier?). But then there was also repeat testing at setting 3 which seems like it would be the same as this test here.

On this repeat setting I showed results of :
right 14, 17 and 14kgf (CV 11.5%)
and left 20, 18 and16kgf (CV 11%).
I am right hand dominant which was mentioned in the report.

On the other five setting test I basically went up from the initial reading for the 2nd and third readings and then down for the 4th and 5th. In both hands the 5th reading was lower than the 1st.

I found it hard to actually hold the device though - I am fairly petite at 5'2"ish and my hands aren't that big. Trying to get my fingers around the device so that I could actually grip it was extremely difficult - I think it would work better for people with larger hands!

 

This is almost the most interesting part of the study: a chronically fatigued non-ME control group (CF/nonME). What an excellent idea! If only more studies would do this. And the result that the CF/nonME patients were close to healthy controls gives weight to our claims that CF and ME are very different conditions.

A question regarding this CF/nonME control group:

I may have misunderstood this but it sounds as if all participants, ME and controls, were found through the Biobank? This is what is says:

What isn't clear to me is whether the Biobank records ME patients differently depending on diagnostic criteria? In table 1 it says (bolding mine):

So the CF/nonME patients actually do have an official doctor's ME/CFS diagnosis but presumably based on less strict criteria. Would this be plainly obvious to other researchers when they access the Biobank? Or do they have to do their own, additional assessment which some may or may not bother with?

 

I agree that this part is very interesting. We need more controls who are CF/nonME.

 

I think this is quite an interesting study.

A lot of studies report their findings in comparison to healthy controls (which is a bit silly IMHO), but here there's a clear differentiation between patients with ME (who's hand grip strength looks more like MS-patients) and patients with chronic fatigue (who's hand grip strength look more like healthy controls). That's quite an achievement for a relative inexpensive test that takes only 3 minutes and which can be used in bedbound patients as well.

An intriguing finding was the drop in hand grip strength in the severe ME group, a drop that was not seen in other patient groups, including MS. This could be the muscle weakness that caught the eye of people like Melvin Ramsay…

I find it a bit disappointing that there were only 3 measurements. It would be interesting to see what would happen if 10 subsequent hand grip strength measurements were taken. In that case, it would be less about strength (which I suppose is affected by deconditioning) and more about post exertional muscle weakness and fatigability (which is said to be characteristic of ME).

If I remember correctly @Simon M is interested in a test that is similar to CPET but less taxing on patients. Would be interesting to hear your take on this.

 

I believe more tests were done. One of the trial subjects mentioned she had five tests upthread. It may just be that three tests are required to spot the change?

 

Hmm, I doubt it. If they had 5 measurements for all these subjects then they would probably have reported it this way.

 

I think this is important. I probably would pass the 3-times-test - as others maybe too - but 10-times would be clear. Also, there are supposed to be aerobic metabolism issues - you won't see that with 3 repetitions.

My strength seems good, but I simply can't repeat a movement for a longer time without symptoms/problems. This is a problem in everyday life, because washing hair, carrying stuff, brushing teeth, taking steps...cannot be done with 1 repetition.

 

I misread @Sbag's post. It seems they tried a few different settings first and finally settled on the protocol that showed results? I could be wrong.

The paper doesn't claim to capture PEM (which I had initially assumed) because it's not done over a long enough period of time (such as being repeated after 24 or 48 hours). It captures weakness and/or fatigue instead.

As with peak flow testing, I suspect the limits of the test would have to published for nurses and doctors, so they know which confounding factors might skew the results.

 

We expect to have a Q&A with the CureME team in the New Year at some point (details still to be arranged), so if you can wait then questions (i.e. how many measurements were taken) can be asked of them then.

 

I didn't mean PEM, I meant weakness/fast fatiguing.

 

Thank you. Yes, I get that. But the aerobic metabolism issues only show up (so far) on the two-day CPET, which is definitely a measure of PEM.

I'm not sure if the weakness possibly shown here is due to aerobic metabolism or some other factor. Of course, it could be, and both factors might be an element of PEM, but it's also possible it's due to other factors, such as signalling issues.

 

For information, this extract has been taken from my personal diary notes, following my first appointment with the Biobank, earlier this month:

“Next test was a grip test. (that the 90 yo's are doing in the Channel 4 'Old People’s Home for 4 year olds' programme! )

3 measurements taken

1, 2, 3 squeeze&hold, 2, 3 release, rest: and

Pause, then Repeated

Measured 12,10,8

Most people would improve. ME worsen. (Found a record online and a “weak” score for a woman of my age is 17.7)”

This was using my dominant hand and I could have sworn that I had gripped harder on the 2nd and 3rd times, having got used to how the machine felt in my hand.

 

This is purely anecdotal, but I used to be the guy with the trick that I could open any screw top container in under a second, no matter how tight. Its mostly physics, but it requires a minimum hand strength. Long ago I went under that threshold, and indeed I worry I will drop whatever it is, and don't even attempt to open many containers.

 

That would be my guess too.