Muscle oxygenation [as assessed by NIRS - Near Infra-Red Spectroscopy]

[ScoutB]

Found this thread from discussions about muscle capillary weirdness here and here.

I noticed Moxy offers a 10-day rental for 80$ for people in the US, so I'm curious if this is still something worth trying. @SNT Gatchaman, let me know if you'd rather leave this topic alone until that study you were hoping for happens, but if you're willing I have a few questions..

1. Did you ultimately end up only trying out the device for just 1 or 2 days? (totally reasonably if so, just calibrating my expectations)
2. Did you feel like the results were a bit hard to interpret? Or that it was possible to use the device wrongly somehow? It sounds like these kinds of concerns were contributing to your caution? (With my current level of fogginess it'll take me a while to dig into this stuff and even understand how much solid information one can get out of the Moxy)
3. If you don't mind me asking -- do/did you have muscles symptoms that made some kind of local issue there seem plausible? (I ask because my symptoms seem mainly immune/brain-ish so I might not be the ideal candidate to try this. OTOH sufficient exercise does seem to trigger PEM somehow for me so ¯\_(ツ)_/¯)
4. It would be pretty exciting if a device like the Moxy could help us avoid worsening symptoms. Did you get any sense one way or another on that while you tried it out? Or is it too hard to say?

 

[SNT Gatchaman]

I haven't had any update on whether the Moxy was found to be adequate for a study or if it's been used. I hope so but the lack of feedback might indicate it was a bust.

1. Did you ultimately end up only trying out the device for just 1 or 2 days? (totally reasonably if so, just calibrating my expectations)

I used it daily for some weeks. Then it's been on the shelf and I recently tried it again to see if anything was different. Same pattern that I'd previously described. For me the measurements seem (and remain) abnormal. I'll do it again this week.

2. Did you feel like the results were a bit hard to interpret? Or that it was possible to use the device wrongly somehow? It sounds like these kinds of concerns were contributing to your caution? (With my current level of fogginess it'll take me a while to dig into this stuff and even understand how much solid information one can get out of the Moxy)

One of my concerns was I found I could get significantly variable results, just shifting the device around a little. That raised the possibility that there was some sort of error in the reading. The alternative that occurred to me was that that might be genuine and an important observation. If the capillary basement membrane thickening / damaged irregular endothelium / microvascular AV shunting that's being suggested by the Wüst and Systrom groups is valid, I'd expect that to be significantly non-uniform. Potentially this is a marker in support, but if so it would make measuring global effects pretty unreliable.

I'll have another look to see if this is still reproducible vs me using it incorrectly.

3. If you don't mind me asking -- do/did you have muscles symptoms that made some kind of local issue there seem plausible? (I ask because my symptoms seem mainly immune/brain-ish so I might not be the ideal candidate to try this. OTOH sufficient exercise does seem to trigger PEM somehow for me so ¯\_(ツ)_/¯)

Yes, I definitely had significantly impaired muscle function, with extremely rapid fatiguability, weakness, trembling. This came with a "zing" of local "lactic acidosis" feeling, as with exerting at the gym or in sports, except occurring with trivial activity or at rest. That still occurs for me but is less common. For context I'm currently housebound, with delay to getting up in the morning, quietly sedentary with feet up til lunchtime, then sedentary with feet-on-floor in a home-office type job in the afternoon, then feet up in the evening. Over the last 6 months I've averaged daily: 21 minutes upright, 1080 steps, 850 m walk distance and my devices tell me my walking steadiness is "low".

4. It would be pretty exciting if a device like the Moxy could help us avoid worsening symptoms. Did you get any sense one way or another on that while you tried it out? Or is it too hard to say?

I'm not sure whether the general wearables ± Moxy could be used to measure PEM or warn of impending PEM. It's something I've had on the back-burner to look into. It would be so much better for pwME if the devices could be doing this passively rather than actively having to fill in interminable questionnaires of activity tracking and all these ecological momentary assessments.

 

[ScoutB]

I used it daily for some weeks. Then it's been on the shelf and I recently tried it again to see if anything was different. Same pattern that I'd previously described. For me the measurements seem (and remain) abnormal. I'll do it again this week.

I see, that's really interesting. Intrigued to hear how it goes/went this week.

One of my concerns was I found I could get significantly variable results, just shifting the device around a little. That raised the possibility that there was some sort of error in the reading. The alternative that occurred to me was that that might be genuine and an important observation. If the capillary basement membrane thickening / damaged irregular endothelium / microvascular AV shunting that's being suggested by the Wüst and Systrom groups is valid, I'd expect that to be significantly non-uniform. Potentially this is a marker in support, but if so it would make measuring global effects pretty unreliable.

Sounds reasonable to me. I guess that 2023 LC study showed even within one biopsy (I assume it was one biopsy per patient) there was a fair amount of variability in the values they looked at.

Thank you for sharing about your symptoms, that's really helpful. It does make me feel like I'm less likely to get an unusual result. My muscles do seem to go anaerobic-feeling too fast, but it's at the level where it stopped me from being able to play soccer or like walk quickly, I don't run into it constantly doing activities of daily living. That said, I think I'll probably try this anyway in the spring (when I'm back in the US) because I don't really see a downside other than I might experience that ironic disappointment one gets with normal test results in MECFS.

I'm not sure whether the general wearables ± Moxy could be used to measure PEM or warn of impending PEM. It's something I've had on the back-burner to look into. It would be so much better for pwME if the devices could be doing this passively rather than actively having to fill in interminable questionnaires of activity tracking and all these ecological momentary assessments.

Yes exactly. Oh and btw, how are you tracking upright time? That's another variable I'm really curious about.

 

[SNT Gatchaman]

how are you tracking upright time?

I think the Apple Watch does this (± in association with the phone). Presumably position and movement of the device are markers. Things like absence of arm swinging with walking, while the watch is facing outwards. It's likely much more sophisticated because the motion sensing chips are quite high resolution.

Looking at the raw data in the Apple Health app it looks like it records in 5 minute blocks and gives a 1-5 minute stand score per block. It doesn't record blocks with zero stand time.

I guess we could try calibrating it against a manual stopwatch, to see if it's accurate for us as with healthy people.