Review Long COVID Is Not a Functional Neurologic Disorder 2024 Davenport, Tyson et al

I've come to think of: the belief that anything can cause any symptoms mimicking illness and anything can undo it, as long as the patient believes in it. And by anything in both cases I literally mean anything. I've seen so many dumb excuses put forward in both cases to be certain that there is no limit to this construct.

Which of course is completely delusional. It's an incredible feat of propaganda that this lives in a description that respect the above, while pretending that it has legitimate "rule-in" signs, which almost no one uses because they all know it's BS. It's probably the most post-truth thing in the modern world, which is fitting since this ideology has existed since before electrification, it was always post-truth.

 

In responding to their inflated prevalence claims, I focused on the fact that they completely misrepresented their own data. Our letter and my related complaints did not address whether the lower prevalence is "right" or any other issue related to what FND is or is not. I thought it was important to highlight that this entire field has engaged in diagnostic creep by highlighting the methodological/statistic problems in taking a reported 5.5% prevalence and clearly inflating it without any justification beyond that they wanted to and could get away with it.

 

Bearing in mind that I'm not a neurologist: The gold standard for "non-epileptic seizures" is nothing abnormal on scalp readings. But my understanding from multiple neurologists is that this gold standard can miss electrical things going on much deeper in the brain. Regarding tremors and other movement-related disorders, there is now acknowledgement from FND experts that some of these can be prodromal symptoms of Parkinson's and maybe other neurological disorders. The dispute seems to be whether they are an FND overlay (FND experts) or whether a later Parkinson's diagnosis means it was Parkinson's all along (other neurologists). In other words, per the former, the same underlying whatever is leading to both FND and then later Parkinson's, so in that case they would be independent diagnoses.

Regarding other work on the positive signs...I have pointed out that their claims of robust evidence these signs--Hoover's sign, etc--indicate FND is based on historical knowledge from neurologists that the FND experts say has been "rediscovered." But all the studies don't show much of anything. As I've reported the most robust study of Hoover's sign included less than 20 patients identified as having FND--but all had been previously diagnosed with FND based partly on a positive Hoover's sign, so the study is based on circular reasoning.

The claim that it's a brain network disease is also based on studies of associations between symptoms and functional MRIs. But every human activity will show some patterns on funtional MRIs. They're taking this association and intepreting it as causal "software" problems--even as they now acknowledge widespread structural issues as well.

And as far as I can tell, the "rule-in" signs for the emerging category of "functional cognitive disorder" are based on pretty much no data at all--just the "clinical observations" of the FND experts. There was a recent Delphi consensus paper that pretty much made this point. You use that methodology when there is basically huge uncertainty, so you collate expert opinion to come up with an uber-opinion. And if the expert opinions are from the likes of Jon Stone and Alan Carson and Michael Sharpe, it's hard to see why anyone would take it seriously.

Another thing that confuses me is that there are lots of papers saying it's challenging to distinguish FND from other clinical presentations. At the same time, they keep saying the rule-in signs are highly specific for FND. I don't see how both can be true at the same time. Either a sign is highly specific, or it's not. They also say clinicians have to make the Dx self-confidently so patietns believe it, becauae believing in it is required for treatment. But if making the distinctions is so challenging, why should clincians be so self-confident?

As we wrote in our STAT opinion piece, an FND diagnosis really seems like a way of saying, we don't know what's going on, so let's give it a name.

I simply can't believe much written by people who routinely inflate statistics, inflate claims of rule-in sign specificity, and completely misinterpret and mispresent their own research--such as the CODES study of CBT for non-epileptic seizures. In a recent paper, they blamed the funders for making them choose the primary outcome of seizure reduction--they now say that's not the best primary outcome, even though the CODES team has been hyping that as the correct primary outcome for 15 years. They're blaming funders for focusing on the primary outcome they themselves have advocated for.

These aren't honest and disinterested researchers, so everything they write seems suspect to me.

 

I have only felt comfortable criticizing their research on methodological grounds. I don't know enough about the neurological But I do know that 5.5% is not 16% and that null findings in a study's primary outcome mean that you can't promote the study as a success based on some modestly positive results on vague secondary outcomes, most of which don't survive adjustment for multiple comparisons (CODES), and that a study of Hoover's sign that includes only a few people with FND previously diagnosed based on a positive Hoover's sign does not provide robust evidence for the specificity of Hoover's sign.

 

Yes, but I doubt many neurologists would say there are no non-epileptic 'seizures'. There will be true epileptic events with little or no abnormality found on EEG between attacks. But if they are typical clinically they are likely to be accepted as true epileptic attacks - certainly if there is a clonic and a tonic phase with tongue biting and incontinence.

Nin-epiletic attacks are often different clinically. I think there is often a clonic phase but no tonic phase. Tongue biting is unusual etc.

I don't think we have good reason to deny that there are non-epileptic seizures. We don't know what they are due to but they not epilepsy.

Maybe a very limited spectrum of cases could be but many unexplained movement disorders are large scale chorea type actions that bear no relation to Parkinson's or any other systemic form of tremor. They are often confined to one painful area. It is very easy to assume that they are 'put on' but over the years I came to realise that in most cases the patient would have no idea that there sort of painful condition was associated with these movements. They had not read the book. The movements cannot have a psychological origin in the sense of being due to some idea. They must reflect some intrinsic feature of the CNS. But they almost certainly originate in the brain through a non-structural mechanism.

Again, I see no reason to deny that these unexplained phenomena are genuinely 'functional' in the operational sense of without a structural lesion. They have nothing to do with known diseases. Parkinsonism is a complete red herring. I have seen several very similar cases over the years.

It takes about ten years to become really competent in neurological diagnosis and it is an extraordinarily complicated decision pathway. Some cases pose challenges in distinguishing. Some don't. A rule in sign is a very reliable way to rule out some recognised pathologist - which is what is really meant. But in some cases things are not clear. Until an AI is programmed to include all the decision weightings of a skilled neurologist no paper is going to give simple answers. And when the AI is programmed you will have trouble reading through the 50 Gigabytes of machine code. It is complicated!

 

Yes, sure, everything is suspect, but if you spent a month as a neurology intern I don't think you would come away thinking that 'functional' problems, as defined operationally, do not exist. In the general population they are probably pretty uncommon but in a neurology service they are around much of the time.

 

This seems reasonable. Many things are not understood. But FND is a term that seems neutral on its face but they load it up with interpretations of etiology that don't seem based on much.

 

Indeed, but that is a different issue. One thing that I intend to add in my updating of my Qeios article is a statement that the word 'functional' has no place in discussion of life-threatening malnutrition. And that will link in to a polite but firm critique of the RCP advice on feeding support.

 

A summary of this article in Swedish is available at the Swedish Covid Association's website:

En medicinhistorisk exposé – framväxten av ME/CFS respektive FND som diagnos
https://covidforeningen.se/en-medicinhistorisk-expose-framvaxt-mecfs-respektive-fnd/