Functional Neurological Disorder (FND) - articles, social media and discussion

[dave30th]

The category has to be there because it describes a group of people with a specific set of symptoms.

well, but the symptoms are all over the place. Some are seizures of various kinds, some are motor paralysis or weakness, some are sensory (hysterical blindness/deafness), others are cognitive (memory, concentration, "brain fog," etc. It sure seems like a jumbled collection of symptoms rather than a specific set. The connecting link is that they purportedly are happening with no evidence of structural changes. The evidence for brain dysfunctions seems to be both absence of evident structural damage and fMRI associations, which lead to declarative statements that all FND, including unexplained cognitive deficits, is related to subtle changes in the brain. And the treatments are always CBT and some form of physio based on distracting people from the symptoms.

I'm sure there are people who fall into that category, but how can anyone know for sure who they are? The FND people say a third of patients attending neurology clinics have FND. They also say many people with Parkinson's, MS, etc. have co-morbid FND because they think the symptoms are not representative of standard Parkinson's or MS symptoms. So anything not directly tied to structural damage gets defined as FND. Is that a fundamental problem with the category, or just with how people are applying it.

In your view, are we talking about a very small percentage of these patients? Or do you think it's really as widespread at the Jon Stones and Alan Carsons make it out to be?

 

[ukxmrv]

I think we can safely assume that there is a lot of pre-emptive priming of FND patients against us and our criticisms by clinicians and researchers in the FND club.

I would agree with that to an extent. On the Facebook groups I belong to there are FND patients who suddenly appear from nowhere and post enthusiastically.

They are similar to the posts from Lighning Process accounts in that they use the same words and refer people to the same FND website.

There is no intention to discuss research or to engage with other patients diagnosed with FND who go on to be re-diagnosed with other medical conditions that can be treated.

It reminds me of the 'death threats' claim. We should consider the possibility that some of this is coming from somewhere.

There might be a reason why some FND people are joining Facebook groups for other medical conditions.

 

[Sean]

@ukxmrv

Certainly not suggesting it is all FND patients.

 

[ukxmrv]

@ukxmrv

Certainly not suggesting it is all FND patients.

Certainly not. On the Long Covid groups there appears to be a genuine group of new and confused people diagnosed with FND. Also the POTS group.

These are UK NHS patients.

 

[Hutan]

I am not sure what the problem is. For structural lesions neurologists have established that an expert clinical assessment can pin almost anything down precisely on the basis of known anatomical connections and functions. If a clinical pattern cannot be fitted into that one has to assume that it arises through more subtle functions. And decades of experience has confirmed that with current techniques no structural lesion is found. Mistakes are made, and scans pick up unexpected things for sure, but having worked under an expert clinician I know that this is mostly clinical laziness. The assessment system, if done meticulously, is extremely reliable at least in terms of defining a very small set of options.

But things are not as clear cut as that. There are papers that throw a lot of doubt on the accuracy of diagnoses of psychogenic seizures. And, in a post further back in this thread, I referred to a paper on neurogenic stuttering:

Neurogenic Stuttering: Etiology, Symptomatology, and Treatment, 2021

The underlying pathophysiological mechanism of neurogenic stuttering is not yet fully understood. Contributing to this is the fact that neurogenic stuttering may be associated with multiple pathologies and with different lesion sites (8). During the analysis of the data on the etiology of neurogenic stuttering, it was found that neurogenic stuttering cannot be exclusively associated with damage to a particular part of the brain, but may involve various neurological structures that are part of the neural network for fluent speech production (11). Neurological structures that may be involved include four lobes of both hemispheres, cerebellum, subcortical white matter, basal ganglia, thalamus, and brainstem (12)

The paper concluded that

The indistinguishability between neurogenic, developmental, and psychogenic stuttering could lead to ineffective assessments and generally inappropriate interventions, which in turn would prevent adequate advances in stuttering therapy

That paper actually supported the idea of a category of psychogenic stuttering as well neurogenic stuttering. The criteria used to distinguish the two sorts of stuttering included these predictable and concerning items:

• the symbolic significance of the disorder

• anamnestic data indicate a history of emotional problems (personality disorder, post-traumatic stress disorder, drug addiction, anxiety, or depression)

• after a short period of therapy rapid and satisfactory progress is noted

For goodness sake, "after a short period of therapy rapid and satisfactory progress is noted" as a criterion for psychogenic causation. Perhaps some swelling went down and a bit of the brain was able to function properly again. Perhaps the patient just wanted to say something encouraging to the therapist. Perhaps the therapist just heard what they wanted to hear.

Health care systems get stuff wrong. They use the wrong sort of scans to see things, the person who looks at the scans was distracted. Yes, clinical laziness, a lack of money for scans, overworked staff. A family member of mine was diagnosed with a stroke last year - two months later someone had another look at the scan, ordered the sort of scan that showed the problem better and worked out it was something else that could be treated. I've spent weeks and weeks in hospitals over the last six months supporting the family member; a lot of the young doctors are clearly floundering around, with some of them making up random stuff to cover over their lack of knowledge.

Even with meticulous assessment, there are some causes of neurological impairment that still cannot be reliably picked up non-invasively. Given that, that idea that FND diagnoses must always be made confidently (in order to cure the patient) is unethical.

 

[Hutan]

On the Long Covid groups there appears to be a genuine group of new and confused people diagnosed with FND.

Can anyone recall that pie chart posted recently with the diagnoses that people with Long Covid were getting? From memory, there was a really small percentage of Long Covid people being diagnosed with ME/CFS - 6%? And a large percentage of people being diagnosed with FND.

 

[Eddie]

I am not sure what the problem is. For structural lesions neurologists have established that an expert clinical assessment can pin almost anything down precisely on the basis of known anatomical connections and functions. If a clinical pattern cannot be fitted into that one has to assume that it arises through more subtle functions. And decades of experience has confirmed that with current techniques no structural lesion is found. Mistakes are made, and scans pick up unexpected things for sure, but having worked under an expert clinician I know that this is mostly clinical laziness. The assessment system, if done meticulously, is extremely reliable at least in terms of defining a very small set of options.

So Hoover's sign, in a full context, indicates that no structural lesion is likely to be found and that we need a term for a more subtle mechanism of malfunction. We have no idea what but that doesn't come in to the process.

In that specific context I understand the use of FND as label. My only pushback is on the implication about causes and on the misuse of that label. I have the same criticism of the people running around saying POTS is an autonomic nervous system issue when we don't know that is the case.

My only point in saying "I don't think a subtle disfunction of the brain's software is an illness" was the part about a disfunction in the brain's software. This is how FND is portrayed and implies that the issue is somehow psychological in nature. In schizophrenia and paranoid psychosis no one suggests that this is an issue with the brain's software. We don't know the specific cause, but from what I understand there are proposals involving issues with dopamine and glutamate as well as some subtle structural brain changes. If the prevailing discourse was that FND was due to a similar mechanism that would be fine, but instead we get these vague brain software analogies. Imagine if the NIH said this about people with schizophrenia: "Someone with FND (schizophrenia) can function normally, they just can't at that moment."

If the Hoover's sign accurately indicates that there are no structural lesions then that is a useful test. But whether the Hoover's sign is evidence of some common FND pathology I am not so sure. It could be the case but as you mention that isn't the goal of the test.

 

[Eleanor]

Can anyone recall that pie chart posted recently with the diagnoses that people with Long Covid were getting? From memory, there was a really small percentage of Long Covid people being diagnosed with ME/CFS - 6%? And a large percentage of people being diagnosed with FND.

Cambridge and Peterborough LC clinic: according to this, 53% of their patients present with "Functional illness", 9% with FND and 4% with ME. Using a "mind-body approach". https://www.s4me.info/threads/unite...r-news-from-scotland.29404/page-4#post-523398

(edited to correct percentages)

 

[Sean]

A serious issue I have with handing out a label, like FND, is that it is not neutral. It contains unproven assumptions about the nature and causation of the condition (in this case that FND is functional & neurological), and they start becoming part of how it is perceived and treated, rightly or wrongly. It predisposes to a certain interpretation, and that tends to blind people to other possibilities, both in research and clinical settings.

As I understand it medicine has for some time been discouraging the naming of conditions after people or places, etc, and instead using names that are more descriptive of the condition's features or underlying pathogenesis, perhaps for good reasons. But that former practice did have the very real advantages of being assumption free about various aspects of the condition, including causation, and minimising confusing and possibly embarrassing re-naming if it later turned out to be technically incorrect.

 

[Hutan]

From the above article:

We made a gold-standard diagnosis of stroke, functional disorder, or other diagnosis based on clinical history and examination, imaging and clinical follow-up.

What's with this 'gold-standard' stuff? It's like it is from a BPS playbook - someone has said 'how can we convince people that we are really right?' and someone else has said 'keep repeating 'gold standard''.

"The sensitivity of Hoover's sign for a diagnosis of functional weakness in those who presented with leg weakness was 63%"

Sensitivity is the test's ability to identify an individual with the disease as positive. So, I think that statement means that 63% of the people diagnosed with functional weakness were positive to the test. 37% were negative to the test but diagnosed as having functional weakness anyway. Who knows what other 'rule in' signs resulted in their diagnosis - their youth, femaleness and history of anxiety perhaps? (there's a paywall to the study)

And the 100% specificity means that none of the people who were negative to the test were diagnosed with functional weakness.

 

[Eddie]

From the above article:

What's with this 'gold-standard' stuff? It's like it is from a BPS playbook - someone has said 'how can we convince people that we are really right?' and someone else has said 'keep repeating 'gold standard''.


Sensitivity is the test's ability to identify an individual with the disease as positive. So, I think that statement means that 63% of the people diagnosed with functional weakness were positive to the test. 37% were negative to the test but diagnosed as having functional weakness anyway. Who knows what other 'rule in' signs resulted in their diagnosis - their youth, femaleness and history of anxiety perhaps? (there's a paywall to the study)

And the 100% specificity means that none of the people who were negative to the test were diagnosed with functional weakness.

Thanks for explaining, I deleted the comment because I came upon David's blog on it which answered the question for me! For some reason I can still get past the paywall using my university log in even though I graduated years ago.

Isn't the specificity claim circular? Don't you have to have a positive test for the weakness to be diagnosed as functional.

 

[LJord]

This isn’t theoretical for me. In an emergency room I was told that the Dr. would not answer my questions because I needed to believe in the diagnosis for the treatment to work. So I’m expected to make an informed decision without any information. The level of disrespect. My brain is so rewired - magically it would seem- that I and others like me are no longer to be treated as competent to make our own medical decisions? I will never know what about my medical presentation triggered that diagnosis because that Doctor would not engage with my questions. When I went looking for answers I found glowing accounts of this medical condition though I did not recognize myself or my symptoms. The treatment is CBT and GET (in the US). When I tried to engage with my really abnormal physical reaction to PT it was blown off - maybe cause he wasn’t answering questions. When the visiting nurse opened the medical records there was no actual information about positive signs just the diagnosis and a medical history that gave me a psyciatric history and neglected to include the history of stroke in my family - most recently my father. The second diagnosis the was no Hoover sign because the test wasn’t done. And again misrepresentation of my medical history and again no engagement around my difficulties with PT. People in my life consider me to be competent. My current therapist (see experience above) thinks I’m competent but now I have FND all over my records. And misinformation. I also have seen the very intense FND patients. I never engage but I simply do not believe that the hoover sign means that when MS or Parkinson’s is finally diagnosed that they have both FND and MS or Parkinson's or even a very scary TIA.

 

[Jonathan Edwards]

well, but the symptoms are all over the place. Some are seizures of various kinds, some are motor paralysis or weakness, some are sensory (hysterical blindness/deafness), others are cognitive (memory, concentration, "brain fog," etc. It sure seems like a jumbled collection of symptoms rather than a specific set.

No, David, the symptoms fall into a specific category: abnormal movements, paralysis, sensory loss, blindness and seizure type movements all suggestive of local neurological lesions but nearly always without any possible interpretation in terms of a known structural lesion no structural lesion is detected. They tend to be stereotyped. As a trainee you doubt these people exist until you come across them in A/E with what it says in the books. That is the category. Cognitive things like brain fog are not part of the definition of FND. If some people complain of these as well that is secondary. The extension of FND to things like ME/CFS is something else - completely inappropriate.

The evidence for brain dysfunctions seems to be both absence of evident structural damage and fMRI associations,

No, the evidence of dysfunction is simply that there are symptoms or signs of dysfunction. The MRI studies are about proving theories in research. In the patients the dysfunction is having a left arm flailing about when there is no reason for it to. There must be some dysfunction in the brain since movements of that sort are controlled by central grey matter in the brain. The theories of people like Mark Edward are wrong but they are not what defines the clinical diagnostic category.

which lead to declarative statements that all FND, including unexplained cognitive deficits, is related to subtle changes in the brain.

But cognitive deficits are obviously due to subtle changes in the brain. They aren't due to the liver!
I am not arguing about the idiocy of these declarative statements. I am pointing out that there is a group of people who share a clinical problem that needs to be called something. I don't like FND, but some of them do and it is mean for others to deny them the reality of their diagnosis if they have nothing better on offer.

Some of the people put in this category will be misdiagnosed and turn out to have supra nuclear palsy or MS. But that is a different issue.

And the treatments are always CBT and some form of physio based on distracting people from the symptoms.

Actually they aren't. I have at times shared care of people with this sort of problem with colleagues at the national Hospital for Nervous Diseases and taken part of multidisciplinary meetings. The discussion at those meetings was often as sensible and open-minded as the discussion here. Everyone admitted that they had no idea what was going on or quite what to do and plans were developed largely as damage limitation exercises to try to find a way of seeing someone through a period of illness none of us understood. I agree that these days a lot of people seem to be getting this wrong, but again that is another issue.

I'm sure there are people who fall into that category, but how can anyone know for sure who they are?

You rarely know anything for sure in medicine, but the situation here is the same as any other. Skilled assessment tends to get things right. In neurology it pays to be obsessive. But there is always a level of uncertainty. Again, this is another issue.

The FND people say a third of patients attending neurology clinics have FND.

But those are just the empty cans making most noise. None of the physicians I know would take that seriously. Unfortunately everything is now done by soundbite, including the medical journals.

So anything not directly tied to structural damage gets defined as FND.

No, that isn't how it is defined. Schizophrenia is not tied to structural change and nobody calls it FND, nor migraine as far as I know. FND specifically relates to a clinical pattern that shows some signs that it ought to be related to a specific localised abnormality but that lesion is not identified at the relevant level. So a seizure ought to be related to an EEG focus or a spot on MRI and in FND it isn't. In Parkinson's the clinical picture is known to be associated with a biochemical change in the substantial nigra that you may only be able to see at autopsy so it is not FND because there is no discordance in findings. Discordance in findings is central to the concept of FDN and I don't think it is unreasonable to think it likely that that discordance occurs in 'higher' brain function in cortex, but that is a million miles away from being 'psychological' in the 'psychosomatic' sense.

In your view, are we talking about a very small percentage of these patients? Or do you think it's really as widespread at the Jon Stones and Alan Carsons make it out to be?

The clinic data are irrelevant for all sorts of reasons to do with triage and ascertainment. I suspect that people who can reasonably be classed as having FND form about 0.05% of the population. They may fill Jon Stone's clinics because he asks for them. I looked after about 1000 people on a regular basis at any one time as a physician. If FND as I understand it occurred in more than 0.1% I should have seen cases as coincidental comorbidities in my patients. I maybe saw one every five years, if that.

 

[Jonathan Edwards]

I think we can safely assume that there is a lot of pre-emptive priming of FND patients against us and our criticisms by clinicians and researchers in the FND club.

Good point.

 

[Jonathan Edwards]

There are papers that throw a lot of doubt on the accuracy of diagnoses of psychogenic seizures.

Nobody is disputing that and we are not even calling them psychogenic seizures. But there are people with seizure-like episodes that are incongruent with standard seizures in typical ways and who over long periods show no evidence of a structural lesion. They need help and doing another MRI every week for ten years isn't the answer, especially if it shows a blob that gets sent inappropriately to a surgeon.

 

[Jonathan Edwards]

In schizophrenia and paranoid psychosis no one suggests that this is an issue with the brain's software.

I think they might well do. The software/hardware analogy is never very good but as far as I know nobody has actually pinned down abnormalities in psychosis. Glutamate and domain could easily be called software since they are signals rather than structure. I see your point but I don't think there is a clear distinction.

Some psychiatrists and neurologists link FND to bad thoughts - even though these seem to be unthought thoughts. Their stories are just incoherent and I agree on that. But the pragmatic category of FND covers a group of people whose illness needs a name - forget any theories or treatments. I don't like FND but I am not sure I have a better suggestion.

 

[Jonathan Edwards]

Cambridge and Peterborough LC clinic: according to this, 53% of their patients present with "Functional illness", 9% with FND and 4% with ME. Using a "mind-body approach". https://www.s4me.info/threads/unite...r-news-from-scotland.29404/page-4#post-523398

This is quit interesting. I suspect it reflects the fact that six doctors prefer to tick the 'functional illness' box, 2 doctors like FND and one dares to diagnose ME. There isn't actually any difference between the patients.

 

[livinglighter]

FND specifically relates to a clinical pattern that shows some signs that it ought to be related to a specific localised abnormality but that lesion is not identified at the relevant level.

What is the relevant level? I've come across literature that says axonal injury/subtle damage occurs at different levels and is permanent, but depending on the level, it cannot always be seen via imaging. Are subtle changes to brain function that arise from subtle damage FND?


[Edited for clarity]

 

[Eleanor]

Cognitive things like brain fog are not part of the definition of FND. If some people complain of these as well that is secondary. The extension of FND to things like ME/CFS is something else - completely inappropriate.

But there are NHS neurologists right now trying to put a FND diagnosis on patients who present with brain fog and fatigue, without any of the signs you list (I've encountered one myself within the past six months and heard of others). So either they do think it's appropriate, or they're just cynically misapplying the diagnosis, which they presumably wouldn't do if they thought it was a meaningful one where an error could have repercussions. Either way, they're not using a working definition of FND which fits that specific and useful category you describe.

 

[Jonathan Edwards]

What is the relevant level?

In reality that depends entirely on the particular context. In each situation the relevant level depends on decades of experience with patterns of illness. In FND there is a discrepancy with any pattern of known mechanism and a discrepancy that appears to require an explanation involving specific errors in cortical function. It is extremely difficult to explain in practice without everyone having trained in neurology. But it is a bit like trying to explain how people know that a chiffchaff is in fact an Iberian chiffchaff, based on subtle incongruity sof song and plumage. These things exist and can be distinguished but it isn't always easy to explain why!