Monitoring Carotid Blood Flow Using In-Ear Wearable Device During Tilt-Table Testing, 2023, Hemantkumar Tripathi MD et al

[Jonathan Edwards]

the great thing about the POTS researchers, and the patients, and this company, and hopefully a few competitors, is they will chug along anyway and we can find out if your view was right.

But will the chugging ever show anything?
The Y axis is number of symptoms - which seems a crazy thing to measure. One bad symptom is enough. Maybe the chart misses the real relation. But this isn't supporting evidence.

 

[Simon M]

That graph is pretty overwhelming evidence that reduced blood flow is NOT the cause of symptoms. A primary main cause does not give a correlation line like that with an R of 0.4. It gives an R of 0.9+.

The Y axis is number of symptoms - which seems a crazy thing to measure. One bad symptom is enough. Maybe the chart misses the real relation. But this isn't supporting evidence.

I agree that symptom count is a weird measure, and wouldn't expect it to show much, so r=0.4 is quite impressive. It would be great to see this work done measuring the overall symptom severity/burden on standing. Maybe there is something impressive to find here

 

[Eddie]

Agreed that number of symptoms is a strange way to gauge OI. I might have 6-8 symptoms after standing for 10 minuets but of those only dizziness, palpitations and my feet getting very red and itchy are significantly uncomfortable. Perhaps they should have measured the self reported difference in overall symptom discomfort between sitting and standing after 10 minuets. Still not perfect, but makes more sense to me than number of symptoms.

 

[Jonathan Edwards]

I agree that symptom count is a weird measure, and wouldn't expect it to show much, so r=0.4 is quite impressive.

Surely 0.4 is what you would expect from all the likely confounding correlations in this situation. If the redution in blood flow was the cause of symptoms even with a crazy symptom score measure I would expect something cleaner than this.

 

[Simon M]

Surely 0.4 is what you would expect from all the likely confounding correlations in this situation. If the redution in blood flow was the cause of symptoms even with a crazy symptom score measure I would expect something cleaner than this.

I don't know, I thought 0.4 was higher than you normally get from things like that. But I still think that using a sensible measure would give us a clear answer.

 

[Utsikt]

It think there was a study where they used a pressure chamber for the lower part of the body to simulate standing and then looked at how long it took before the participants fainted. Maybe that would be a good measurement to compare the blood flow against?