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

[Jonathan Edwards]

The neuroimaging discussion just indicates that the authors do not know how to assess pathological findings in this sort of context. With populations of unknown and unstandardisable heterogeneity you cannot conclude anything.

 

[Trish]

Apologies this is a bit of a ramble and may not make sense or be particularly relevant or useful. I'm just posting it because I've written it. I've put most of it in a spoiler so as not to clutter up the thread discussion.

I've decided to take a more thorough look at the historical and definitional aspects of this article. I'm leaving the sections on details of biomedical evidence to others to comment on as I don't feel qualified to judge the soundess or otherwise of the details.

Spoiler: Neurasthenia as the precursor of ME/CFS and FND

Starting with this paragraph:

1. Introduction
Severe fatigue that impairs usual function long has been described throughout recorded human history. The neurologists Beard [1] and Charcot [2] were among the first to characterize the health condition ‘neurasthenia’ in the latter half of the 19th century. Based on this common historical root in neurasthenia, two divergent scholarly and clinical paths have taken shape over time. The first path involves a pathogenic disease model rooted in the scientific process, resulting in a rich literature describing pathobiology and various attempts at creating specific case definition criteria. This path has resulted in the label of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The second path is a psychosomatic/sociogenic illness construction that has incorporated ideas from contemporary neuroscience into an unbroken conceptual chain linking back to neurasthenia. This path has resulted in the label of functional neurologic disorders (FND).

This part is just plain wrong in my opinion:

The first path involves a pathogenic disease model rooted in the scientific process, resulting in a rich literature describing pathobiology and various attempts at creating specific case definition criteria. This path has resulted in the label of [ME/CFS].

Definitions of neurasthenia and ME/CFS are based on descriptions of symptoms, not on causes.
For example:

Definition of Neurasthenia:
The Tenth Revision of the World Health Organization's InternationalClassification of Diseases (ICD-10) presents a set of well-defined inclusion and exclusion criteria for thediagnosis.2 The core symptoms are identified as mental and/or physical fatigue, accompanied by at least two of seven symptoms (dizziness, dyspepsia, muscular aches or pains, tension headaches, inability to relax, irritability, and sleep disturbance).To make the diagnosis, it must be a persistent illness. Exclusion criteria include the presence of mood, panic, or generalized anxiety disorders.

This describes a pattern of symptoms that could well lead to the people diagnosed with neurasthenia in the 19th century being diagnosed with ME/CFS today. Equally it could lead to some being diagnosed with burnout, stress related fatigue and all sorts of other fatiguing illnesses that do have clear pathology such as MS.

There is a clear path from neurasthenia to current BPS models of ME/CFS, and has been since the 1980's and probably earlier.
For example, 34 years ago:
Old wine in new bottles: neurasthenia and 'ME' S Wessely

. . . the true successor to neurasthenia only appeared in the 1980s, with the arrival of chronic fatigue syndrome (CFS).
Wessely S. Neurasthenia and chronic fatigue syndrome: theory and practice. Transcultural Psychiatric Review 1994;31:173-209.

I have a particular fascination with the history of neurasthenia, which I think is now accepted as the precursor of CFS/ME. The parallels between neurasthenia and CFS are many and inescapable.
Wessely S. “To tell or not to tell”: The problem of medically unexplained symptoms. In ; Ethical Dilemmas in Neurology (eds Zeman & Emanuel), WB Saunders, 1999, 41-53

Wessely also equates CFS with burnout:

If the work-relatedness was left out of the equation then burnout would indeed equate to CFS or fatigue, not least given the 96% overlap between CFS and neurasthenia, for example, reported from one CFS clinic.
Leone S, Wessely S, Huibers M, Knottnerus J, Kant U. Two sides of the same coin? On the history and phenonomology of burnout. Psychology & Health 2011: 26: 449-464.

And Michael Sharpe in 2010

Neurotic, stress-related and somatoform disorders
Michael Sharpe, ... Jane Walker, in Companion to Psychiatric Studies (Eighth Edition), 2010

Neurasthenia as defined in ICD-10 is characterised by a persistent and distressing complaint of increased fatigue after mental effort, or persistent and distressing complaints of bodily weakness and exhaustion after minimal effort. Neurasthenia is broadly equivalent to chronic fatigue syndrome (CFS)

Neurasthenia
The term neurasthenia has a long history, and before Freud was essentially an amorphous concept covering all neurotic disorders. It remains a diagnosis in ICD-10 to describe a syndrome of chronic fatigue. In DSM-IV, however, chronic fatigue enjoys no special status and simply falls into the residual category of undifferentiated somatoform disorder (with fatigue as the symptom).

Definition
Neurasthenia as defined in ICD-10 is characterised by a persistent and distressing complaint of increased fatigue after mental effort, or persistent and distressing complaints of bodily weakness and exhaustion after minimal effort. Neurasthenia is broadly equivalent to chronic fatigue syndrome (CFS) (Fukuda et al 1994).

Clinical features
Patients with neurasthenia present with the predominant compliant of physical and mental fatigue, exacerbated by exertion. They commonly have symptoms of depression and anxiety, but fatigue is predominant. These patients are more commonly seen in medical than psychiatric settings, and often receive diagnosis such as postviral fatigue, or sometimes myalgic encephalomyelitis (ME). They may have strong beliefs about a medical aetiology for their condition which reduces the acceptability of psychiatric management.

Aetiology
The current understanding of aetiology is that, like pain, it is probably multifactorial (Afari & Buchwald 2003). There is some evidence for a genetic predisposition. There is also some evidence for precipitating life events, and possibly a triggering role for medical conditions such as viral infection. Neurasthenia can certainly develop after acute Epstein–Barr virus infection (glandular fever). Neurasthenia is not necessarily a stable diagnosis, and may change to cases of depression or anxiety. It has been proposed that there are subgroups of neurasthenia that have different and specific organic aetiologies, although this remains to be established.

Epidemiology
Fatigue is common in the general population, but the diagnosis of neurasthenia less so. One study found that although 13% of the population complain of prolonged and excessive fatigue, less than 2% met ICD-10 criteria for neurasthenia, and less than 0.5% neurasthenia without comorbid anxiety and depression (Hickie et al 2002). Neurasthenia (and CFS) is more common in women.

Treatment
The available evidence suggests that antidepressant treatments are of limited value, but there is good evidence for rehabilitative psychological treatments, including CBT and simple graded exercise therapy (Whiting et al 2001).

Prognosis
Mild cases of fatigue tend to fluctuate, although established cases of neurasthenia tend to persist and to follow a chronic course.

I think the Oxford criteria (Sharpe 1991), the clear history of equating ME and/or CFS with Neurasthenia, and its psychosomatic attibution is an essential part of the history of ME/CFS.

I think it's also notable that the Oxford criteria, with its requirement only for chronic disabling fatigue, is an even broader umbrella than neurasthenia which required at least 2 other symptoms and which explicitly excluded 'the presence of mood, panic, or generalized anxiety disorders'. The Oxford paper specifically includes these mental disorders, and only excludes major psychiatric disorders such as schizophrenia.

I think by muddling together causes and symptoms this section confuses rather than enlightens.

As far as I can see, neurasthenia is a symptom description, not an attribution of aetiology.

Getting back to the article in this thread, the introduction ends:

However, psychosomatic/sociogenic illness constructs continue to influence the contemporary discourse related to long COVID [34]. This clinical perspective will anchor the current discourse regarding long COVID into the historical context involving a parallel development of ME/CFS (predominately pathobiological) and FND (predominately psychosomatic/sociogenic) diagnostic constructs. This perspective will now review the clinical findings and neurobiological pathology of long COVID, developing a clinical and scientific rationale for why it is inappropriate to consider long COVID as FND.

I don't feel qualified to comment on the FND history of association with neurasthenia, nor with its psychosomatic attibution, but it seems to me that ME/CFS and FND have followed very similar paths of a set of symptoms, largely focused on fatigue in ME/CFS and on neurological signs and sympoms in FND, and with some links back to the set of symptoms described in neurasthenia, have been developed along two paths, but not split in the way the authors of this paper describe.

Rather than the split being, as they suggest, between ME/CFS = biomedical path, FND = psychosomatic path.

This is my understanding of the split:

Biomedical scientists and some clinicians: ME/CFS and unexplained neurological signs/symptoms = biomedical but biology not yet fully elucidated, diagnostic criteria for both overlap with those for neurasthenia

BPS proponents, mostly psychiatrists and neurologists: ME/CFS and FND are psychosomatic and the successors of neurasthenia/conversion disorder/hysteria.

 

[Trish]

More ramblings, this time on PEM.

Quoting from the article:

Ramsay first coined the term epidemic malaise to describe the phenomenon of muscle weakness that was worsened upon repeat testing [38,39]. This observation of a physical performance decline in response to a previous exertion was formative to developing contemporary case definition criteria for ME/CFS. PEM/PENE is now recognized as a whole host of unusual signs and symptoms following exertion, such as profound fatigue, cognitive dysfunction (such as impairment in attention, short-term memory, and performing mental calculations), sleep disturbance, clinical presentations consistent with viral reactivation (such as fevers, swollen glands, and pharyngitis), body and joint pains, headaches, and muscle weakness [43,44,45,46,47,48,49,50]. PEM/PENE appears responsible for the episodic disability observed in people living with ME/CFS. Episodic disability suggests a person’s physical and cognitive abilities may vary substantially within a short term of hours to days (i.e., microcycling) and a long term of weeks, months, and years (i.e., macrocycling) [51,52]. In addition, PEM/PENE has increasingly become a component of case definition criteria over time to differentiate the phenomenon of debilitating fatigue, among other signs and symptoms, after exposure to a pathogen or toxin from other causes of fatigue.

That attempt to describe PEM as a host of symtoms following exertion, and PEM being 'responsible for episodic disability' seems unhelpful to me. It both confuses cause and effect, and conflates 'symptoms after exertion' ie fatiguability' with delayed PEM which is both an increase in already existing symtoms and some new ones, and decreased ability to function for days or longer.

PEM is not the cause of eplsodic disability, one of its features is increased disability. The idea of it cycling seems to suggest a pattern of cycles of health and relapse, or ability and disability. And whether it 'cycles' or the pattern is continuous rolling PEM or rare PEM may depend on disease severity and life circumstances allowing adequate pacing (and luck).

The symptoms listed and many more are features of ME/CFS, not solely of PEM. The existence of these symptoms is not a sign the person is in PEM, it's a sign they have ME/CFS. Most of us have symptoms and disability all the time, we don't have cycles of disability.

This reminds me of the problems with Sarah Tyson's questionnaire PASS that purported to be about PEM but was about symptoms after exertion, muddling together PEM with fatiguablity.

Why not differentiate muscle fatiguability from PEM and use a clear definition of PEM that incorporates exertion above the person's current limited capacity, delay of a day or two in onset of PEM, significant increase in ME/CFS symptoms, additional symptoms, significantly decreased ability to function and duration exceeding a day, often much longer.

I think the attempt to conflate Ramsay's description of muscle fatiguablity with PEM is unhelpful.

I haven't come across the microcycling and macrocycling idea for PEM, has anyone else? It doesn't seem particularly helpful to me. Do they mean microcycling is short term fatigablity and macrocycling is PEM?

 

[Jonathan Edwards]

I agree. I don't see PEM as a physiological concept. It is about a temporal pattern of symptoms. I doubt Ramsay's observation of fatiguability has much to do with CPET studies although it may have even the motivation for doing them.

 

[Trish]

More ramblings, this time mostly on FND, and comparisons with criteria and aetiological models of FND and ME/CFS

Spoiler: more blah blah

Reading the section on FND, there seem to be two possibly contradictory definitions given in the article:

FND is now classified by the International Classification of Diseases (ICD-11) [59] as a dissociative neurological symptom disorder, defined as a mental health condition involving a loss of connection between thoughts, memories, feelings, surroundings, behavior, and identity

Box 1. Diagnostic criteria for functional neurologic disorder [61]

• One or more symptoms of altered voluntary motor behavior or sensory function
• Clinical findings provide evidence of incompatibility between the symptom and recognized neurological or medical conditions
• The symptom or deficit is not better explained by another medical or mental disorder
• The symptom or deficit causes clinically significant distress or impairment in social, occupational, or other important areas of functioning, or warrants medical evaluation

The first specifies it's a mental health condition, says it's a synonym for conversion disorder, and and focuses on mental processes, the second specifies it as unexplained and defined by symptoms.

So which one of these are the authors arguing is LC is not? The mental illness or the set of neurological symptoms?
___________________-

Despite poor-quality supporting research [73], mainstay interventions for FND continue to include psychodynamic and cognitive-behavior therapies to address emotional processing. Thus, despite the original intent [74] and subsequent rationalizations [75] of the principal proponents of FND, this brief historical analysis indicates a continuous underlying conceptual thread that remains unbroken between neurasthenia, through hysterical neurosis and somatoform disorders, leading to the contemporary psychosomatic/sociogenic illness construction of FND.

The thing that strikes me most about this section is you could substitute ME/CFS for FND in that description and you would get the BPS approach to ME/CFS as inflicted on us for over 3 decades. Far from sailing merrily along the biomedical route with lots of research to support it, we have been, and largely still are, stuck in the same place as FND.

ME/CFS and FND both have diagnostic criteria based on descriptions of symptoms, ME/CFS and FND both have limited and often poor quality biomedical research and no clearly established biological aetiology, ME/CFS and FND both have powerful medical proponents of psychosomatic aetological models, and pwME and pwFND are both subjected to largely ineffective psychobehavioural treatments.

So in arguing that LC is sometimes ME/CFS, but is never FND, which definitions or aetiology are the authors objecting to? The diagnostic criteria based on symptoms, the different models of aetiology for each?

I guess I have to read on to find out.

 

[Deanne NZ]

Ok, so this might NOT be THE SEMINAL PAPER to squarely prove that LC is not FND if you are an academic or expert in either condition. Perhaps it was underfunded or under time pressure and could have been better. Hopefully there will be more papers on this in the near future that can draw on some of the critiques made here.

I get the sense there was an urgent need for this paper with the proliferation of stuff coming from the FND folk & increase in numbers of dubious “practitioners” & “coaches” emerging on social media. I have seen posts about people with LC being diagnosed with FND in the USA, Australia, Ireland & NZ.

As a layperson, if I was one of those people and googled and found this paper, it would be good enough for me to use to challenge the diagnosis, or at least try to. I think it would also be sufficient to at least seed doubt in the minds of GPs or other healthcare workers about the appropriateness of an FND diagnosis.

No doubt the FND community will find flaws in the paper and come up with counter arguments. The advantage is that this then provides specific points to counter in the next paper so it can be even more robust.

So my perspective remains that this is still a worthwhile paper to have out in the wild right now. It’s good enough to help some people.

It is going to take a lot more than 1 paper to settle this.

 

[Trish]

I don't know why I'm ploughing on with this. I have no idea whether this is helpful. Perhaps I want to try to contribute to making subsequent papers from this group more useful. There is clearly a need for something to stop pwLC being wrongly diagnosed as having FND when they don't and as being assumed to be psychosomatic, and I commend the effort.

Proponents suggest that just the label of FND may be helpful for some patients who live with troublesome but medically unexplained symptoms and signs [76,77].

I guess that depends how the clinician explains it. If they use the symptom based definition and explain the cause is unknown and they get some help with coping with the symptoms, why not accept it if you find it helps to have a name to attach to your symptoms. I can't imagine being happy with the label if I'm given the mental health explanation and am told the old name was hysteria and the bizarre Freudian conversion disorder explanations.

Even still, the DSM-V-TR diagnostic criteria for FND indicate this label should not be provided when an alternative diagnosis is more compelling. For example, ME/CFS should not be considered as a functional disorder because more specific case definition criteria best explain its constellation of symptoms, signs, and pathophysiology. However, some prominent medical organizations have conflated PEM/PENE with FND because some symptoms of PEM/PENE are represented among the DSM-V-TR case definition criteria for FND.

I have underlined 'and pathophysiology' because it's wrong. Again they are muddling together symptoms and aetiology unhelpfully. As far as I know, none of the diagnostic criteria for ME/CFS say anything about pathophysiology, nor should they, since it's not established.

Is it true that medical organisations conflate ME/CFS and FND on the basis of symptoms. Or is it on the basis of assumed psychosomatic cause? Just asking, I don't know.

 

[Trish]

4. Evidence Refutes That Long COVID Should Be Considered a Functional Neurologic Disorder
FND refers to medical and neurologic symptoms that fail to match any existing medical or neurological conditions [82]. It is a rare syndrome, affecting around 4–12 per 100,000 people despite a suggestion that it is commonly diagnosed in neurology clinics [83]. FND is usually diagnosed when patients are observed to experience seizure-like spells in the setting of normal electroencephalography (EEG) or when they demonstrate abnormal movements or paralysis that are incongruent with their neurologic exam and neuroimaging. In some patients, FND may occur alongside other diagnosable entities, such as long COVID. In this scenario, the clinician should evaluate and treat those diagnosable entities, and refrain from considering the entire patient presentation as “functional” simply because functional aspects may be present. While the rate of misdiagnosis with FND in patients with long COVID is unknown, clinical experience suggests that many patients with complex chronic disorders in general have been misdiagnosed with anxiety, depression, or FND at some point in the course of their illness (Box 2).

That all seems pretty sensible to me. In fact, why not stop there, it's all that needs to be said.
Edit: They probably should add that currently unexplained or functional does not mean psychosomatic, it simply means the physiological explanation has not yet been found.

You'll be pleased to here I'm stopping there. I've run out of energy, and it's nice to end on a positive note.

 

[Sid]

19th century concepts of neurasthenia and hysteria (later called conversion disorder, now called FND) were not considered to be the same disorder. Neurasthenia had symptoms along the lines of what we call ME/CFS or POTS today whereas hysteria had to do with motor or sensory issues like weak limb or blindness in the absence of an identifiable neurological disease. My impression is that only in recent years, since the likes of Stone came on the scene, is everything being lumped in with FND including things like tired all the time, eyelid twitching and subjective cognitive complaints. True FND is extremely rare. I’m struggling to think of a real case I’ve seen in real life.

 

[Jonathan Edwards]

The trouble is @Deanne NZ , that I suspect rather than seed doubts this sort of paper merely confirms beliefs that ME/CFS is a concept based on half-baked ideas of physiology from a group of physios that patients lap up but don't hold water. Even the GPS are aware of this debate. They know there are all sorts of theories about ME being physical. If I were still practicing and read this having not seen prior debate I would be mademoiselle skeptical.

We can't win the war of getting doctors to understand by using weak arguments.

 

[Hutan]

4. Evidence Refutes That Long COVID Should Be Considered a Functional Neurologic Disorder
FND refers to medical and neurologic symptoms that fail to match any existing medical or neurological conditions [82]. It is a rare syndrome, affecting around 4–12 per 100,000 people despite a suggestion that it is commonly diagnosed in neurology clinics [83]. FND is usually diagnosed when patients are observed to experience seizure-like spells in the setting of normal electroencephalography (EEG) or when they demonstrate abnormal movements or paralysis that are incongruent with their neurologic exam and neuroimaging. In some patients, FND may occur alongside other diagnosable entities, such as long COVID. In this scenario, the clinician should evaluate and treat those diagnosable entities, and refrain from considering the entire patient presentation as “functional” simply because functional aspects may be present. While the rate of misdiagnosis with FND in patients with long COVID is unknown, clinical experience suggests that many patients with complex chronic disorders in general have been misdiagnosed with anxiety, depression, or FND at some point in the course of their illness (Box 2).

That all seems pretty sensible to me. In fact, why not stop there, it's all that needs to be said.
Edit: They probably should add that currently unexplained or functional does not mean psychosomatic, it simply means the physiological explanation has not yet been found.

But I reckon even that paragraph is full of problems.

FND refers to medical and neurologic symptoms that fail to match any existing medical or neurological conditions [82].

FND is not when the medical and neurologic symptoms fail to match existing medical or neurological conditions. It is when doctors believe that the symptoms don't match existing conditions or other physical conditions that may be identified in the future. The symptoms may in fact match, and the problem is in the doctors' inadequate knowledge or the technology they have. And FND involves a belief on the part of the doctor that the reported problems could be overcome by the patient thinking better.

It is a rare syndrome, affecting around 4–12 per 100,000 people despite a suggestion that it is commonly diagnosed in neurology clinics [83].

We don't know how many people have it, or indeed if any do. It is nonsense to present prevalence figures as if they are facts.

FND is usually diagnosed when patients are observed to experience seizure-like spells in the setting of normal electroencephalography (EEG) or when they demonstrate abnormal movements or paralysis that are incongruent with their neurologic exam and neuroimaging

That isn't true and seems to be a fundamental misunderstanding on the part of the authors. FND is not just seizures and abnormal movements and weakness - it can include cognitive dysfunction, ME/CFS and fibromyalgia and headaches and persistent coughs. The broader functional spectrum includes all sorts of thing such as IBS, incontinence - anything where the doctor feels that there is no physical reason for the symptoms. @sarahtyson - you need to understand that ME/CFS is very much seen as an FND, and, at present, there are pretty much only beliefs and some still only promising indications from research that differentiate the two. If you have ME/CFS, then the psychosomatic proponents believe that you have an FND.

In some patients, FND may occur alongside other diagnosable entities, such as long COVID. In this scenario, the clinician should evaluate and treat those diagnosable entities, and refrain from considering the entire patient presentation as “functional” simply because functional aspects may be present.

But which bit of Long Covid shouldn't be regarded as FND? The fatigue, the intermittent muscle weakness, the brain fog - most of the core symptoms are in fact entirely compatible with the BPS view of functional disorders.

 

[Trish]

Thanks for providing a different perspective, @Hutan. I think part of the difference of opinion is because we are talking at cross purposes. It depends a lot on which definition of FND you are talking about, the narrow range of neurological symptoms of unexplained aetiology, as in the diagnostic criteria in Box 1, or the ICD definition that calls it a mental health disorder. I read this paragraph as referring to the diagnostic criteria based on symptoms and unknown aetiology.

I liked the paragraph I quoted because it said clearly that FND should only be applied to a very limited range of symptoms, with a couple of examples given. I don't think the paragraph says anything about aetiology, only that the symptoms don't fit a recognised neurological disease and it's rare. I have no idea what the source of the numbers is, so I can't comment on that.

It then goes on to say that some people with other conditions may also have FND in this narrow sense. I took that to mean it was referring to comorbid conditions. It's possible that it could happen at the same time as ME/CFS and any other symptosm all in the same person. It's saying the FND bit should be restricted to the specific symptoms, and not assumed to subsume the rest of the pwLC's symptoms, and also lists a whole lot of other conditions which have been misdiagnosed as FND and argues against that. Surely that's helpful.

I knew I should steer clear of discussing anything to do with FND. I simply don't know enough about it.

 

[Hutan]

Thanks for providing a different perspective, @Hutan. I think part of the difference of opinion is because we are talking at cross purposes. It depends a lot on which definition of FND you are talking about, the narrow range of neurological symptoms of unexplained aetiology, as in the diagnostic criteria in Box 1, or the ICD definition that calls it a mental health disorder. I read this paragraph as referring to the diagnostic criteria based on symptoms and unknown aetiology.

The first sentence of the paragraph cites the DSM5-TR. That is the Diagnostic and Statistical Manual of Mental Disorders. In that manual, Functional Neurological Disorder has 'Conversion Disorder' in brackets after it. The list of diagnostic criteria in Box 1 is cited as also being from the DSM. So, the contents of Box 1 and the DSM definition that calls it a mental health disorder are all one and the same. They aren't two different conceptions of FND.

You might think that Box 1 refers to a narrow range of neurological symptoms. It often does not.

One or more symptoms of altered voluntary motor behavior or sensory function

It can be and often is interpreted as covering a very broad range of symptoms. Sensory function is taken to include cognitive function and that is taken to include brain fog, fatigue and tiredness.

The symptom or deficit is not better explained by another medical or mental disorder

ME/CFS is a group of symptoms that has been given a name. A diagnosis of ME/CFS is not protection against a diagnosis of FND by those who see ME/CFS as a subset of FND.

I liked the paragraph I quoted because it said clearly that FND should only be applied to a very limited range of symptoms, with a couple of examples given. I don't think the paragraph says anything about aetiology, only that the symptoms don't fit a recognised neurological disease and it's rare. I have no idea what the source of the numbers is, so I can't comment on that.

We might prefer FND to only be applied to a very limited range of presentations requiring non-epileptic seizures and/or a funny walk, but it usually isn't. You don't have to have seizures or gait issues to be given an FND label. Someone with ME/CFS compliant symptoms and no seizures or limb paralysis easily qualifies for an FND diagnosis.

 

[Sean]

We can't win the war of getting doctors to understand by using weak arguments.

Or to accept.

We are also having to fight with one hand behind our back, in that the standard biomedical arguments have meet to be accepted are much higher than those for psychosomatic arguments. It should not be that way, but in practice it is.

I knew I should steer clear of discussing anything to do with FND. I simply don't know enough about it.

That puts you on the same level of knowledge as the entire FND movement.

 

[Trish]

Thanks @Hutan, I stand corrected. I knew I shouldn't try to discuss FND. I have previously steered clear of the FND sections of the forum most of the time as I have no experience or expert knowledge of things like movement disorders or non epileptic seizures and don't feel qualified to comment about other people's experience of them or the appropriateness or otherwise of collecting them under an FND label.

I was trying to make the point that if FND were restricted to a narrow set of very specific rare unexplained symptoms that would prevent pwME and pwLC being wrongly diagnosed with FND unless they have those symptoms as a separate comorbidity.

At least we can agree that nobody with ME/CFS or LC should be diagnosed with FND on the basis of brain fog, muscle weakness which are part of ME/CFS. I think that's the point of this article. FND should not be used as an alternative diagnosis for LC.
_____

I would find an article on this subject more helpful if it took ME/CFS and and FND in turn and laid out clearly the diagnostic criteria based on symptoms for each, then explained clearly the different approaches to aetiology for each with enough history to show how those causal models arose and the evidence, or rather lack of evidence for each. There would also need to be a clear explanation about the term 'functional' and how it's misused to interpret currently unexplained symptoms as psychosomatic.

Then bring in LC and explain its an umbrella term for all post covid symptoms, list the main subcategories such as damaged organs and ME/CFS,
then finally conclude that FND is not a relevant or appropriate label for ME/CFS or LC.

 

[Jonathan Edwards]

I think there may be confusion with FMD - functional movement disorders - which is more or less what they seem to be talking about. The problem came when that gotblurred out into FND. All a complete mess.

 

[Trish]

(Also FND is not even FND)

It's all on message but where is this mysterious "pathophysiology"? The case for this not being FND isn't to do with physical evidence. I am not sure that claiming so does more than dent the credibility of the authors and the case.

The fact that ME/CFS (and Long Covid) looks different to functional seizures and functional motor disorders doesn't prove that ME/CFS (and Long Covid) aren't also functional disorders. Functional seizures and functional motor disorders present very differently from each other too. The imagination of psychosomatic medicine proponents has no trouble scooping all of them up into the 'functional' bucket.

We don't know how many people have it, or indeed if any do. It is nonsense to present prevalence figures as if they are facts.

That isn't true and seems to be a fundamental misunderstanding on the part of the authors. FND is not just seizures and abnormal movements and weakness - it can include cognitive dysfunction, ME/CFS and fibromyalgia and headaches and persistent coughs. The broader functional spectrum includes all sorts of thing such as IBS, incontinence - anything where the doctor feels that there is no physical reason for the symptoms.

Can someone help me out of my confusion about FND?

We have seen and apparently supported David Tuller spending a lot of effort getting people publishing papers that quote higher prevalence for FND and giving alternative lower figures, so does that mean we accept that some people have a condition accurately called FND? Or should David Tuller instead have been pointing to evidence that FND is not a thing at all?

Why is it OK to refer to functional movement disorders, and functional seizures, but not to use an umbrella term like FND as an overarching diagnostic category?

What arguments does anyone think should be used to justify the heading of this article, LC is not FND?

• FND doesn't exist, so no one should be diagnosed with it?
• FND is a rare neurological set of conditions that aren't seen in LC apart from rare comorbidity?
• FND is a disguised version of psychosomatic so does not apply to LC because...?
• FND and LC have different symptoms?
• Or what?

 

[Jonathan Edwards]

Whether or not it is OK to refer to FMD is a matter for debate. But the concept is reasonably well defined around certain specific clinical presentations - non-epileptic seizures and rhythmic movements such as tremors and choreoathetosis (slower rhythmic movements of whole limbs usually). These are quite clearly mediated by nerve activity directly but without any evidence of structural lesions. There is some likelihood that these all have a similar origin in the brain, although only a likelihood and it may well not be so.

Once you get wider than that it is much less clear that the problem is neurological in the same way and far less likely that there is any common factor to all presentations. When LC is called FND it simply means people are thinking themselves ill when they are not. There is still a lingering confusion relating to McEvedy and Beard and ME that may be relevant. The clinical presentation of the acute illness at the Royal Free had specific neurological features that are not features of ME/CFS. They weren't movements but at least specifically neurological deficits.

 

[Kitty]

Whether or not it is OK to refer to FMD is a matter for debate. But the concept is reasonably well defined around certain specific clinical presentations - non-epileptic seizures and rhythmic movements such as tremors and choreoathetosis (slower rhythmic movements of whole limbs usually). These are quite clearly mediated by nerve activity directly but without any evidence of structural lesions. There is some likelihood that these all have a similar origin in the brain, although only a likelihood and it may well not be so.

I can see why clinicians would find it useful to have a group term for these symptoms.

It's harder to understand why they can't call them non-epileptic seizures, or tremors, or choreoathetosis in individual patients, though, because that's what they're experiencing and need help with. I'm feeling mithered by psoriasis, and doctors are happy to call it that even though they go a bit hand-wavy about the cause. Calling it a skin disease might be accurate, but it's not useful.

 

[rvallee]

The symptoms may in fact match, and the problem is in the doctors' inadequate knowledge or the technology they have

Only technology matters, the alternative is perception. Once you get to the level of perception you've already lost. Not because it can't work, but because everything has been built around needing specific technology, even where those responsible refuse to build it. And with the current biomedical vs biopsychosocial, the divide has been standardized and bureaucratized, with zero adequate oversight or process.

In the last few decades, the growing response has been to use more perception and even reject technology. A trend that ironically will only end once technology advances enough (AI) to do away with this entire failed paradigm, taking failed perception out of the loop.

It's not said enough just how plain weird we are as a species.