"Cerebral blood flow is reduced in ME/CFS during head-up tilt testing even in the absence of hypotension or tachycardia... van Campen et al, 2020

Interesting study, especially the "hidden" OI.

One grumble though: if I understood correctly some patients fit Fukuda and others CCC. But then they just seem to have lumped them all together. In such a large cohort that seems like a missed opportunity to look separately at them or, even better, to look separately at Fukuda without PEM, Fukuda with PEM, and CCC. Maybe the few whose CBF didn't change much were non-PEM patients?
Kitty said:
It would be interesting to look at people with other conditions causing stiff PRBCs, to see if they have the same response to it.... (Thinking ahead too quickly, as always – obviously the first priority would be bigger studies in ME!)
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You're not thinking too fast. A prompt replication study that includes a disease control group as well as healthy controls would be great.
Milo said:
-then whether this happens for a healthy control who has been paid to spend 1-2 months horizontal.
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I think a little while ago there was a call for participants for a study that was looking at the effects of prolonged bed rest on healthy people. Or something along those lines. Wonder if CBF was on the list of things they were going to look at.

In the present study, if I understood correctly, they excluded the most severe patients because they didn't want to expose them to the strain of the test. So mobile sedentary controls would be suitable.
Milo said:
-could it be considered a biomarker?
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Maybe not a biomarker as we don't know yet how specific to ME the findings are. But could be useful for proving disability. If you were an employer, would you risk employing someone with such compromised brain function?
 
Ravn said:
I think a little while ago there was a call for participants for a study that was looking at the effects of prolonged bed rest on healthy people. Or something along those lines. Wonder if CBF was on the list of things they were going to look at.

In the present study, if I understood correctly, they excluded the most severe patients because they didn't want to expose them to the strain of the test. So mobile sedentary controls would be suitable
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Yes, the prolonged bed rest study is what i had in mind.

and in regards to the more severe patients, they made them sit up.
 
strategist said:
Something else is that maybe the anecdotal positive effect of magnesium is related to improved brain blood flow.
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And perhaps other nutrients that improve blood flow?

What is somewhat frustrating (for me) is the fact that NO, a substance that blood vessel cells produce to relax and make the blood vessels larger to accomodate blood flow, can inhibit ATP production because NO can bind to proteins in the mitochondrial involved in oxidative phosohorylation. Hypoxia can induce NO synthesis.
 
Denise said:
@DokaGirl - I think you are correct that other studies by Rowe have shown a high %age of OI but if I remember correctly those were (mostly?) in pediatric patients who often had pronounced OI symptoms. This study seems to indicate that when symptoms don't show up on a HITT practitioners might need to be more open to treating for OI and/or checking CBF.
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I mean, if such a high percentage have CBF problems, there would be no need to test.

If patients report OI, you may as well just treat it, because they're very likely telling the truth.

(This is assuming the results hold up, of course.)
 
adambeyoncelowe said:
I mean, if such a high percentage have CBF problems, there would be no need to test.

If patients report OI, you may as well just treat it, because they're very likely telling the truth.

(This is assuming the results hold up, of course.)
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Unfortunately the treatments are not all that effective. It may help patients sit up or stand up, but it does not improve enough to get people back to work. And the meds may help with BP or HR, but seemingly you can still have reduce blood flow to the brain. Why, would be the question. Is it the heart? is it endothelial dysfunction? Is it auto-antibodies?

i just hope they will not mass produce a full length compression body suit contraption and declare us ‘recovered’ :laugh:
 
About six months after onset, an otologist suggested that my dizziness might be caused by constriction of the tiny capillaries of the inner ear. It was recommended that I take niacin in an attempt to dilate these tiny blood vessels, but it didn't help (and, in my case, the side effects of niacin were often severe and unpredictable).

Just makes me wonder if widespread constriction of the smallest blood vessels in the brain would be detected as reduced cerebral blood flow. This would probably only get worse if reduced blood cell deformability (as mentioned by @rvallee) were also an issue.
 
Ravn said:
But could be useful for proving disability. If you were an employer, would you risk employing someone with such compromised brain function?
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I'm not sure – it could certainly compromise people doing certain jobs, but as someone who's always had OI, I suspect those prone to it will naturally avoid going into those occupations.

I realise it isn't the case for everyone, but OI has only ever affected me when sitting upright at times when I was too ill to work anyway. The rest of the time, I can't detect much difference between sitting and lying. People who struggle to stand for any length of time will just do what I did, and grab a chair for tasks that involve standing (I remember the most common one when I first started work was trying to persuade militant photocopiers to co-operate! :rolleyes:).
 
ahimsa said:
Even if these percentages end up being lower in any repeat studies in the future, the fact that patients had reduced CBF, even when they had apparently normal tilt table tests, is quite interesting. It would explain several of the folks on the who had symptoms during a tilt test (and who get symptoms while standing in line, taking a shower, etc) but had "normal" results on the tilt test.

This assumes that this measurement is reliable (I know nothing about measuring CBF).
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Haven't had a chance to read this paper yet but I do recall Stewart et al made observations in POTS research suggesting that unexpected and significant oscillations in CBF pressure/flow were associated with symptoms in that cohort.

I wonder if not capturing, or averaging in some way, these oscillations might represent a "normal" tilt table finding to the unaware.
 
Hutan said:
We heard these findings last year, I think Peter Rowe spoke at the NIH conference?
Miriam Tucker covered it in an article here (you have to sign up to Medscape to see it).

Here are two threads where there was some discussion:
Members poll - orthostatic intolerance

Orthostatic intolerance
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see also recent discussions in

https://www.s4me.info/threads/pots-definition-diagnosis-and-symptoms.13522/

(Sorry - there may have been a ‘better way’ to add a thread from this forum, like @Hutan did in the above quote.)
 
@Tom Kindlon

to continue discussions in this thread.

The above symptoms mentioned in the study are exactly the sort of thing I experienced during my tilt table test and I only managed 20 minutes, not the 30 mins like in the study.

I have made comments in all of the threads where we have previously discussed PoTS, OI (see links in above posts) and have diary notes of my very unpleasant experience.

The discharge letter from Consultant to GP clearly reads that “dysautonomia is not the cause of her symptoms. There was no evidence of PoTS, orthostatic hypotension or other condition.”
 
Probably not directly related, but I thought it was interesting to see this tweet about measuring blood flow to the brain in astronauts yesterday:



Pretty sure they are using a different method of measurement.

But still, undergoing tilt table tests and measuring blood flow to the brain - two things that ME patients may have in common with NASA astronauts! :nerd:
 
Knowledge about reduced CBF perfusion in ME goes back quite a ways.

Dr. Ismael Mena, one of the authors of the 2011 ME-ICC, did a study reported in Dr. Byron Hyde's 1992 book; pages 432-438.



Dr. Mena's research is titled: Study of Cerebral Perfusion by NeuroSPECT in Patients with Chronic Fatigue Syndrome.

- 46 adults with cfs were studied: 30 females, and 16 males, along with 10 healthy controls.

Under "Discussion": "71% of the patients presented with unilateral or bilateral pattern of hypoperfusion in the temporal lobes."



Here is the MEpedia link for info about Dr. Mena: https://me-pedia.org/wiki/Ismael_Mena

Here is the MEpedia link for Dr. Hyde's book: https://www.me-pedia.org/wiki/The_C...ic_Encephalomyelitis/Chronic_Fatigue_Syndrome

Here is the link for the ME-ICC (International Consensus Criteria) https://me-pedia.org/wiki/International_Consensus_Criteria
 
Here is an interesting paper on cerebral blood flow:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914489/

Cerebral blood flow and autoregulation: current measurement techniques and prospects for noninvasive optical methods

Abstract.

Cerebral blood flow (CBF) and cerebral autoregulation (CA) are critically important to maintain proper brain perfusion and supply the brain with the necessary oxygen and energy substrates.

Adequate brain perfusion is required to support normal brain function, to achieve successful aging, and to navigate acute and chronic medical conditions.

We review the general principles of CBF measurements and the current techniques to measure CBF based on direct intravascular measurements, nuclear medicine, X-ray imaging, magnetic resonance imaging, ultrasound techniques, thermal diffusion, and optical methods.

We also review techniques for arterial blood pressure measurements as well as theoretical and experimental methods for the assessment of CA, including recent approaches based on optical techniques.

The assessment of cerebral perfusion in the clinical practice is also presented.

The comprehensive description of principles, methods, and clinical requirements of CBF and CA measurements highlights the potentially important role that noninvasive optical methods can play in the assessment of neurovascular health.

In fact, optical techniques have the ability to provide a noninvasive, quantitative, and continuous monitor of CBF and autoregulation.
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DokaGirl said:
Knowledge about reduced CBF perfusion in ME goes back quite a ways.

Dr. Ismael Mena, one of the authors of the 2011 ME-ICC, did a study reported in Dr. Byron Hyde's 1992 book; pages 432-438.



Dr. Mena's research is titled: Study of Cerebral Perfusion by NeuroSPECT in Patients with Chronic Fatigue Syndrome.

- 46 adults with cfs were studied: 30 females, and 16 males, along with 10 healthy controls.

Under "Discussion": "71% of the patients presented with unilateral or bilateral pattern of hypoperfusion in the temporal lobes."



Here is the MEpedia link for info about Dr. Mena: https://me-pedia.org/wiki/Ismael_Mena

Here is the MEpedia link for Dr. Hyde's book: https://www.me-pedia.org/wiki/The_C...ic_Encephalomyelitis/Chronic_Fatigue_Syndrome

Here is the link for the ME-ICC (International Consensus Criteria) https://me-pedia.org/wiki/International_Consensus_Criteria
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I’ve never had a SPECT scan but I presume they are generally done supine. The supine cerebral blood scores were quite similar between healthy controls and the three ME/CFS groups. (See Table 2). So in some ways it looks like the results don’t match.
 
It’s interesting how a widely (it appears) alternative method [transcranial Doppler] may have problems associated with it:
It is generally assumed that part of the OI symptomatology is related to cerebral hypoperfusion(Freeman et al. , 2011, Sheldon et al. , 2015, Shen et al. , 2017). Indirect cerebral blood flow measurements such as those obtained by transcranial Doppler studies, provide inconsistent support of this hypothesis(Coverdale et al. , 2014, Verbree et al. , 2014, Park et al. , 2017, Novak, 2018). A limitation of transcranial Doppler is that it measures cerebral flow velocities, not cerebral blood flow. For transcranial Doppler cerebral blood flow velocity measurement to be a valid indicator of total cerebral blood flow, an important assumption is that intracranial vessel diameters would have to remain unchanged during an intervention. Changes in vessel diameters affect flow velocities(Kantos, 1992) independent of the intervention. During head-up tilt test hypocapnia may develop(Naschitz et al. , 2000, Novak, 2018). Previous studies have shown that hypocapnia can reduce intracranial vessel diameters, thereby altering the relation between flow velocity changes and hemodynamic changes(Coverdale et al. , 2014, Verbree et al. , 2014, Al-Khazraji et al. , 2019).

Using extracranial Doppler imaging of the carotid and vertebral arteries, taking both flow velocity and vessel diameters into account, we recently demonstrated the feasibility and reproducibility of measuring total cerebral blood flow during head-up tilt test in healthy controls(van Campen et al. , 2018). The aim of the current study was to use the same technique to measure whether orthostatic symptoms in ME/CFS are associated with a cerebral blood flow reduction.
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Would anyone have an idea whether there would be many similar testing facilities available in clinical (as opposed to research) environments in other countries?

It could be useful for helping to show disability as mentioned in the paper and also above.
 
As mentioned above, not every single person had orthostatic testing:
Participants in whom orthostatic testing was thought to be too taxing due to the severity of their illness did not undergo orthostatic stress testing. In a minority of patients an alternative orthostatic stress test with cerebral blood flow measurements was used (while sitting and standing), to demonstrate the effects of positional changes on cerebral blood flow (also done because of social security claims).
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