Self-selecting bias for CCSVI

A forum to discuss Chronic Cerebrospinal Venous Insufficiency and its relationship to Multiple Sclerosis.

Self-selecting bias for CCSVI

Postby Cece » Tue Mar 09, 2010 8:54 am

I've mentioned to my husband how stunning it is, to see some of the imagery being posted by people here who've had the MRV done and are missing a jugular or have a bone occlusion or a narrowing. It seems like the percentages of people here having CCSVI are higher than what Buffalo found. My husband suggested that it could be a self-selection bias. The CCSVI theory made sense to me and fit with my symptoms, so I stuck around...for those for whom it's not as good a fit, they don't stick around.
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Postby ozarkcanoer » Tue Mar 09, 2010 8:58 am

I think there is a self-selecting bias for CCSVI when the Dr and patient and the people who carry out the imaging know that the patient has MS. That is why blinded trials similar to the one at BNAC are necessary. We should all pay attention to all the CCSVI clinical trials that have already started and that are being planned. It is the results of these trials, not personal anecdotes, that will convince our doctors (or not) of the validity of CCSVI.

However, the personal anecdote are what give us hope... so keep all the personal stories coming !!!

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Postby Cece » Tue Mar 09, 2010 9:13 am

Ozarkcanoer, that is a different kind of bias too (which could result in false positives). I am trying to say that the people who present themselves to be investigated for CCSVI are more likely to actually have it. No bias in terms of the diagnosis...just bias in terms of who selects themselves to go see if they have it...for example, for myself, I have symptoms that are far better explained by CCSVI than by strictly autoimmune MS and so I've stuck around.

But then again I suppose the Buffalo trial was full of MSers presenting themselves to see if they had CCSVI?

I agree with you about the personal anecdotes. I'm scheduled to see Dr. Sclafani, the doctor who Wheelchair Kamikaze has talked about, in early May. It feels daring to even imagine it but how I would love to write a personal glowing anecdote, sometime in late May, about warm feet and lessened fatigue and a sense that yes it worked!
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Postby ozarkcanoer » Tue Mar 09, 2010 9:42 am

Cece,

I'm looking forward to your CCSVI adventure. Best of luck !

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self-selecting bias for ccsvi

Postby simone » Tue Mar 09, 2010 10:48 am

Cece & Ozarkcanoer,

I understand about blinded trials but what I don't get is, if a jugular vein etc.....
is missing in anyone, isn't that a a problem? As well as the evidence is there with the currant technology. Is the technology in question? the people reading it? How does bias fit in here?
Just so happens that people with MS are a probable lot to test.
Any enlightenment on this would be much appreciated , as the way it looks right now to me is "this is the scientific way we play this game".

Best wishes to All......
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Postby ozarkcanoer » Tue Mar 09, 2010 10:58 am

simone, I think Cece means that the patient himself/herself is biased in favor of CCSVI. It has nothing to do with any real physical condition, but it may be that those people who think CCSVI might fit their symptoms will seek diagnosis and treatment for CCSVI. Am I right, Cece ?

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Postby simone » Tue Mar 09, 2010 11:38 am

Ozarkcanoer, certainly the patient would be biased but what i meant is the structure of "blinded trials" in the case of either it is there or it is not.
Kind of like " suspecting the earth is round then checking with modern tools to see". Well , something like that. What i mean is , even knowing someone has ms what difference would it make when you test? what is there in knowing, that would alter the tests?
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Postby Cece » Tue Mar 09, 2010 1:07 pm

Let's see...by self-selecting bias I meant something like this example...

There are a hundred people in a room. Doctor steps in and says, "Hey, I need ten of you to fill out a quick questionnaire on headaches, first ten to step forward are in." Ten people step up, all turn out to have daily headaches. The conclusion could be that 100% of people (10 out of 10) have daily headaches...but those people self-selected themselves. If the doctor comes into the room and instead selects people at random, then there is no self-selecting bias and maybe 1 out of 10 have daily headaches.

Anyway by our own presence here, I think we may be self-selecting ourselves. I think you could go into a different forum and take ten MSers at random and then ten MSers here and we'd have measurably more or worse CCSVI. I think the reason we are here is because the theory resonates with our own personal experiences and symptoms. Hypoxic events just before relapses, anyone? (I was hiking on Mt. Haleakala, on my honeymoon.) Cold feet of the literal sort? It's a self-selecting bias but it works in our favor. CCSVI can be tested for and treated.

Simone, there are blurry shades of gray, or so it seems, when it comes to interpreting some of the imaging. A missing jugular is obvious, but there are people with a small pinching of the vein or a narrowing throughout, and it's not as clearcut...so some of that gets interpreted by the pro-CCSVI doctor as being CCSVI and worthy of treatment and the neg-CCSVI doctor as being nothing. That is where the bias is.
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Postby simone » Tue Mar 09, 2010 3:07 pm

Cece wrote:Let's see...by self-selecting bias I meant something like this example...
I think the reason we are here is because the theory resonates with our own personal experiences and symptoms. Hypoxic events just before relapses, anyone? (I was hiking on Mt. Haleakala, on my honeymoon.) Cold feet of the literal sort? It's a self-selecting bias but it works in our favor. CCSVI can be tested for and treated.

Simone, there are blurry shades of gray, or so it seems, when it comes to interpreting some of the imaging. A missing jugular is obvious, but there are people with a small pinching of the vein or a narrowing throughout, and it's not as clearcut...so some of that gets interpreted by the pro-CCSVI doctor as being CCSVI and worthy of treatment and the neg-CCSVI doctor as being nothing. That is where the bias is.


Yes , I agree.
Thanks ,
s
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Re: self-selecting bias for ccsvi

Postby codefellow » Tue Mar 09, 2010 4:22 pm

simone wrote:Cece & Ozarkcanoer,

I understand about blinded trials but what I don't get is, if a jugular vein etc.....
is missing in anyone, isn't that a a problem?
Simone


The problem is that no doctor can ethically perform ANY unnecessary procedure. So there has to be a strong chance (or a proven track record) that if you have this PROBLEM, then this PROCEDURE can be used to help mitigate or alleviate it.

Lets say I do NOT have MS or any symptoms of MS, but my left jugular vein shows pronounced stenosis. If the stenosis in my left jugular vein is not interfering with my normal life, then there is NO justification for surgery to correct it. The risk clearly outweighs the benefit.

I am confident we will reach a point where the CCSVI/MS connection is as obvious as it needs to be to always justify the Liberation procedure, and I think we are getting there....but we are not there yet.
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Postby simone » Tue Mar 09, 2010 5:25 pm

Got it Codefellow, thanks. Have been having thick brain fog and difficulty understanding the resistance of neurologist to actually want to see.
Yes it is in process thanks to you all!!!!!!!!
S
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Postby suze » Wed Mar 10, 2010 2:25 am

Does anyone know whether all pwms have Dawson's Fingers or venocentric deposits of iron? I know some pwms have such a pattern of damage but if they all do then veins must be somehow involved, even if no stenosis can be found.
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Postby Cece » Wed Mar 10, 2010 11:08 am

I think the newest MRI machines, the Tesla 7s, show tiny microlesions following the veins. I don't know if that's in all MSers or what percentage.
"However, the truth in science ultimately emerges, although sometimes it takes a very long time," Arthur Silverstein, Autoimmunity: A History of the Early Struggle for Recognition
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Re: Self-selecting bias for CCSVI

Postby willowford » Tue May 03, 2011 7:18 pm

Cece wrote:I've mentioned to my husband how stunning it is, to see some of the imagery being posted by people here who've had the MRV done and are missing a jugular or have a bone occlusion or a narrowing. It seems like the percentages of people here having CCSVI are higher than what Buffalo found. My husband suggested that it could be a self-selection bias. The CCSVI theory made sense to me and fit with my symptoms, so I stuck around...for those for whom it's not as good a fit, they don't stick around.


Cece,

Thanks for referring me here. It's interesting to me that you proposed this idea as well! (It's something that doctors talk about among themselves but don't usually explain to patients because they don't want them to lose hope - well, most of them anyway).

Either way, another reason why this forum is much more informative and objective than other sites. It seems that even some of those individuals like yourself who have CCSVI, had it treated, and are better for it, are STILL looking at the evidence and waiting for answers for others. It's a breath of fresh air to see!

I think docs need to see these sites too, to see that at least there are many patients who like them still believe in objective evidence.
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Postby Cece » Tue May 03, 2011 10:18 pm

I think docs need to see these sites too, to see that at least there are many patients who like them still believe in objective evidence.

Thanks, willowford, I'd hope the docs would take a look at what we're doing here and on the Facebook site before making any unflattering conclusions. The social media aspect of CCSVI is a phenomenon, it is something altogether new, but I do not think of it as a bad thing. In general MS patients here at these sites are intelligent and capable. There is also a risk/benefit analysis that we all make and some are more comfortable with risk or more drawn to the benefit than others. We do the best with the information we have and I think we are all aware that we do not yet know all there is to know about CCSVI.

We might not have the answers but we have the questions and that is more than a start. :)

('What effect does CCSVI treatment have on MS progression?' HUGE question which I am personally invested in knowing the answer to.)
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