Diagnosis and management of functional neurological disorder, 2022, Aybek and Perez

[Kitty]

From @MSEsperanza:

It seems this BMJ review from 2022 has received no thorough published critique yet -- at least nothing linked on the Altmetric page, and on the BMJ article only two endorsing responses.

However, 2 references on wikipedia and 81 citations in medical papers.

Altmetric – Diagnosis and management of functional neurological disorder: https://bmj.altmetric.com/details/121487051/citations

(Just stumbled across this article when searching for something else and didn't want to add another draft to my drafts folder.)

@dave30th

 

[Hutan]

Funding: SA was supported by the Swiss National Science Foundation grant PP00P3_176985.

Just noting I've seen the Swiss National Science Foundation come up as a funder of psychosomatic research a bit lately. Perhaps due to the influence of the insurance companies?

From memory, Cochrane has a funded Insurance Medicine Group in Switzerland.

 

[Hutan]

Thanks to @Chandelier for the link to the free access pdf - see the first post of the thread. I think we must have discussed this paper elsewhere or perhaps one very much like it, because I certainly remember this sign:

Teddy Bear sign
Observe if a stuffed animal is brought by the patient during vEEG monitoring: when yes,suggestive of FND

In 104 FND v 147 epilepsy patients: specificity 88% sensitivity 13%

It's quite hard to believe that A. someone did a study of that, and B. someone thought it was worth mentioning in a diagnostic sign list.

And, that's actually one of the better evidenced signs listed. Most seem to have been validated on a sample of about 10 people with 'FND' and 10 healthy controls, and even then, not all the cases showed the sign and some of the controls did.

 

[Hutan]

We searched the Medline, PsycInfo, and Cochrane databases from inception to 1 November 2020 to find articles pertaining to motor FND (weakness and abnormal movements subtypes) and seizure type FND. Our search terms included “functional”, “psychogenic”, “conversion”, “dissociative”, and “hysterical.” More comprehensive details on search terms are available in the supplementary file.

Just in case there was any doubt as to what these signs apply to, there are the search terms, including 'hysterical' and 'conversion'.

 

[Hutan]

More tests:

Tremor Distractibility
Pause during ballistic movement or during other motor/mental task or change in amplitude and frequency
In 50 FND tremor v 160 other tremors: specificity 92%, sensitivity 94%

Tremor Entrainment
Ask to imitate tapping motion with one hand and observe the change in tremor frequency on the other
In 50 FND tremor v 160 other tremors: specificity 91%, sensitivity 91%

They sound convincing don't they, with their specificity and sensitivity in the 90% range? From a 2016 paper


Here's a 2024 paper:
Parkinson’s Disease tremor can show entrainment and distractibility with electrophysiological assessment using tapping test.

Objective: To examine whether features described in tapping test are specific to functional tremor by evaluating rest and postural tremor in PDpatients using the same protocol for assessment of functional tremor.​

​

Background: Electrophysiological tests such as the tapping test are used to distinguish functional and non-functional tremors.​

​

Patients with functional tremor commonly show entrainment, frequency shift of the tremor of more than 1.5 Hz, and amplitude reduction (>50% decrease relative to baseline) during tapping of the contralateral hand.Tremor in Parkinson’s disease is known to increase in amplitude during cognitive tasks and have spontaneous fluctuations. However, the tapping test has not been tested in Parkinson’s disease (PD) tremor.​

​

Method: We evaluated 20 PD patients (3F, age 64.9±7.6[mean±SD] years) with rest and postural tremor and without clinical diagnosis of functional tremor component using surface electromyography and triaxial accelerometry. The tremor was evaluated in the moreaffected arm at rest and with arms outstretched. Tremorswere recorded while tapping at 1, 3 and 5 Hz with the contralateral arm paced by a metronome. Tremor amplitude and frequency were calculated using the average from power spectrum analysis of the three axesfrom accelerometer recordings, and tapping and no taping conditions were compared. The accuracy of the tapping was also measured.​

​

Results: Rest tremor showed reduction of amplitude in 4 patients while tapping at 1 Hz and in 3 patients while tapping at3Hz with the contralateral hand. Moreover, rest tremorshowed entrainment in 4 patients while tapping at 3Hz. Postural tremor was suppressed in 3 patients while tapping at 1 Hz and 1 patient with 3Hz taping. There was entrainment with frequency shift in 2 patients while tapping at 3 Hz. Nineteen patients had an increase in amplitude of rest tremor while tapping at 5 Hz, the same happened in 10 patients with postural tremor.​

​

Conclusion: Distractibility and entrainment can be found in PD tremor and is more common in rest tremor than postural tremor. The tapping test at 1 and 3 Hz may not reliably distinguish between PD tremor and functional tremor.​

So, there is a decent chance that people with Parkinson's will be labelled as having an FND with this list of tests. Or, probably these days, an FND overlay.

 

[Hutan]

When assessing tics, no validated signs are available but clinical clues can help identify functional tics110 111: lack of premonitory urge and inability to suppress the movement, female preponderance, additional FND symptoms, lack of response to anti-tic medication, and absence of family history. In functional tics, the cranial region is less affected, the type of tic is often “blocking” (ie, interferes with voluntary action) and pali, echo, and copro phenomenon are less common

As with the teddy bear sign, there is strong bias towards diagnosing FND in women. It looks to me as though if you are a man with tics you are likely to get a Tourette's diagnosis. if you are a woman with tics, you are likely to get an FND diagnosis.

Overall, the evidence for rule-in motor signs shows very high specificity, which advocates for their routine use in clinical practice. A range of educational pictorial and video libraries illustrate many of these signs.2 101 102 112 113 Too much emphasis on a single sign, however, can lead to false positives. In a cohort of 190 patients diagnosed with a neurological disorder, 37 (20%) had at least one positive functional neurological sign.91 Interestingly, regression analysis showed that this 20% of the cohort had typical risk factors known in patients with FND, suggesting that the presence of positive signs in this subgroup could either be false positives or indicate the presence of an FND comorbidity.

Keep in mind the possibility that the patient has both FND and another neurological disorder: recent reports describe functional neurological signs in a subset of patients with Parkinson’s disease114 115 or multiple sclerosis.116 Overall, data from a systematic review and a prospective study underscore that rates of misdiagnosis in FND since 1970 (once confirmed) are low, and between 1% and 4%.117 118

That seems to be saying - don't worry about misdiagnoses, they are very rare. And, if the person turns out to have a neurological disorder, well, they probably have FND as well. It's a sort of 'heads, I win', 'tails, you lose' situation. It's the ideal diagnosis for the neurologist who isn't very good, because it seems extremely difficult to be proven wrong.

 

[Chandelier]

Thanks to @Chandelier for the link to the free access pdf - see the first post of the thread.

Pleasure.
There are 2 strategies that I use that sometimes lead to a non-paywalled PDF:
- https://scholar.google.com/ sometimes lists a different version that directly links to a PDF.
- websearch:

filetype:pdf paper-name

I think we must have discussed this paper elsewhere or perhaps one very much like it, because I certainly remember this sign

Yes, the teddy bear paper was this scientific sounding masterpiece:
Evidence-Based Practice for the Clinical Assessment of Psychogenic Nonepileptic Seizures, 2020, Baslet et al.

 

[Nightsong]

2 strategies that I use that sometimes lead to a non-paywalled PDF

In addition to these, for patients without academic access, there's CORE.ac.uk (a large repository of links to open-access versions of papers); the Unpaywall browser extension, as well as Archive.org Scholar, and of course PubMed's PMC that will often find open-access links. I think Elsevier/ScienceDirect also has some kind of patient access scheme although I've never used it.

 

[Hutan]

How to explain the diagnosis

"Central to delivering a diagnosis of FND is the language used—a topic that has been debated for decades. Pejorative terms such as “hysteria” or
“pseudoseizures” are no longer acceptable.154 155 However, debate continues regarding use of “functional” versus “psychogenic.” Support for the term “functional” includes: (1) it is a neutral framing that embraces the causes and mechanistic heterogeneity of this condition within the
biopsychosocial model; (2) it parallels the transient reversibility of symptoms reflected in diagnostic criteria; (3) it aids acceptance given the lack of overt connotations to a mental health condition; and (4) it avoids mind-body dualism.156-159 Arguments in favor of “psychogenic” include: (1) it is a term that closely couples the condition with psychiatric or psychological care; (2) the term “functional” has a complicated history itself—and patients experience their symptoms as “dysfunctional”; and (3) “functional” can contribute to a sometimes unhelpful function-versus-structure dualism (replacing one misguided dualistic framing with another).160- 162

Efforts have been made to operationalize the communication of a FND diagnosis—framing this as the first step in treatment.170 Early strategies to conceptualize the diagnosis as “good news” have fallen out of favor as this can be perceived as invalidating.170 In the literature, communication approaches recommended by Hall-Patch and colleagues include: (1) validating symptoms as genuine and common; (2) naming the condition; (3) providing a brief mechanistic explanation (eg,“brain becomes overloaded and shuts down”); (4) addressing effective and ineffective treatments; and (5) fostering a hopeful sentiment of improvement (eg, pointing out that treatments are available).171

Describing FND as akin to a “software rather than a hardware problem” and symptoms occurring when the “computer crashes” is another helpful
mechanistic explanation.172 173 Showing patients their “rule-in” signs and referring back to those features when discussing the diagnosis is an expert recommendation that has been widely adopted174; similarly, focusing on the “what” of diagnosis rather the “why” can help avoid overly simplistic attempts to link FND symptoms to stress.175 High yield “how to” articles written by FND experts have further contributed to the dissemination of good clinical practices regarding communication approaches172 176 177 (an illustration on how to deliver a diagnosis is provided in video 1, supplementary file 1).

Additionally, providing patients with written materials (eg, www.neurosymptoms.org) can further enhance their understanding.156 Improved education for physicians is needed around delivery of the diagnosis,178 given that neurologists find FND a challenging condition to discuss with patients and to document within the medical records.179-182 A clinical practice survey in 2018 from the International Parkinson and Movement Disorder Society, however, showed that members were more likely to communicate a FND diagnosis without ordering unnecessary tests compared with 10 years prior.183"

 

[Jonathan Edwards]

A clinical practice survey in 2018 from the International Parkinson and Movement Disorder Society, however, showed that members were more likely to communicate a FND diagnosis without ordering unnecessary tests compared with 10 years prior.

And what about making an FND diagnosis without ordering necessary tests?

 

[Hutan]

Treatments

Therapeutic options range from explanation alone to complex multidisciplinary rehabilitation. Triaging patients in the appropriate pathway is important and should, when possible, be individualized to specific clinical characteristics (an illustrated guide on triaging managing decisions is presented in video 2, supplementary file 2).

Sounds as though that training video would be a delight.

Communicating the diagnosis as the first step
In patients with seizure type FND, delivery of the diagnosis has been shown in a small minority of patients to result in cessation of seizures or decreased seizure frequency.184-189 For example, in 54 patients with seizure type FND, 27% achieved seizure remission in the week following communication of the diagnosis.185 Studies have also shown that post diagnosis, emergency department visits and inpatient hospitalizations decrease,43 with a shift toward increased use of outpatient psychiatric services.190

However, it remains unclear if fewer patients overall are utilizing healthcare.191 The long term benefit of communicating a diagnosis of seizure type FND, if used in isolation, also remains unclear.192 More research is needed on the immediate impact of the delivery of a diagnosis of FND in other subtypes.

Communicating the diagnosis doesn't sound very effective as a treatment. It's surprising that they couldn't muster up much evidence for decreased health care use, because I would have thought telling someone their condition is hysteria, no matter what nice words are wrapped around it, would tend to result in the person losing trust in clinicians and giving up on trying to seek help.

Psychoeducation
Several studies have investigated the efficacyof augmented educational interventions.193-197 One RCT evaluated the benefit of three monthly
psychoeducation sessions (n=34) versus routine follow-up (n=30) in patients with seizure type FND.194 No differences in frequency of seizures were recorded at a group level; however, the intervention group reported significantly improved psychosocial functioning at three and six months. In a mixed FND cohort (n=193) and their relatives (n=152) attending a single 105 minute multidisciplinary education session, significant increases in diagnostic understanding, acceptance, belief of treatability, and hopefulness were observed across all in attendance.196 A large RCT in 186 patients with functional motor symptoms investigated the efficacy of online education and self-help interventions (n=93) compared with usual care alone (n=93), and showed no incremental benefits in terms of health status.197 Thus, while patient satisfaction is generally high for educational initiatives, their use in isolation does not appear to positively affect recovery from FND.

Psychoeducation looks to be hopeless in changing health status e.g. frequency of seizures,, although is somewhat useful in changing how FND patients and their families answer surveys.

(there are more treatments e.g. physiotherapy, psychotherapy, drugs - but I think I have to stop for the night.)

 

[Sean]

How to explain the diagnosis​

​

blah blah blah blah blah...​

If you are having to spend that much time and effort on figuring out how to market your product, then you don't have a good product.

 

[Hutan]

Actually, I'll do one more treatment - physiotherapy

The paper notes a range of unconvincing results from physiotherapy trials and then says

More research is needed regarding the management of commonly present non-motor symptoms, such as pain and fatigue.204 A large scale RCT for physiotherapy for motor FND currently under way will likely help clarify some of these questions.205

205 is the Physios4FMD trial, which was, to put it mildly, an absolute bust.
The thread for that paper is here. There was no improvement in the primary outcome of physical functioning, secondary outcomes were astonishingly poor.

After accounting for withdrawals (n=11) and loss to follow-up (n=14), the primary analysis included data from 241 participants (138 [91%] assigned specialist physiotherapy and 103 [90%] assigned treatment as usual). Physical functioning, as assessed by SF36, did not differ significantly between groups (adjusted mean difference

The incredibly poor outcome would be laughable, except that various misdiagnoses came to light during the year and one of the trial participants in the physiology treatment arm committed suicide.
It's easy to see how an approach described in this review as

creating a positive expectation of improvement

physiotherapy should be psychologically informed, including recognizing and exploring unhelpful thoughts and behaviors.

could easily lead to despair and self-blame when the promised improvements don't come.

 

[Chandelier]

The incredibly poor outcome would be laughable, except that various misdiagnoses came to light during the year and one of the trial participants in the physiotherapy treatment arm committed suicide.

Thanks for your thorough analysis, @Hutan
This is shocking! What a nightmare!

How to explain the diagnosis​

​

blah blah blah blah blah...​

If you are having to spend that much time and effort on figuring out how to market your product, then you don't have a good product.

It’s as if we could glimpse into the inner workings of a marketing team that couldn’t care less about the product itself and is all-in on a "fresh & modern data-driven approach" to present <the product> as whatever yields the most positive survey responses.

This is an apple —> negative response
This is an orange —> negative response
This is a barber stool like the one you wanted as a child! —> positive response. We’re going with that one. Good job, team!

Imagine for a moment that they would apply the same rigour to finding the actual cause of the problem.
No matter whether the underlying reason is an apple, an orange or that fancy barber stool.
Imagine if they wouldn’t stop until the patient is objectively better instead of dispatching them to whatever… a gardening course.

 

[rvallee]

That seems to be saying - don't worry about misdiagnoses, they are very rare. And, if the person turns out to have a neurological disorder, well, they probably have FND as well. It's a sort of 'heads, I win', 'tails, you lose' situation. It's the ideal diagnosis for the neurologist who isn't very good, because it seems extremely difficult to be proven wrong.

Even putting it as "extremely difficult" undersells it. It's completely impossible to prove wrong, because there can always be an opinion of a "functional overlay", the field has been building up the case for years that they can coexist and be impossible to tell apart. This isn't a few rogue ideologues, everyone practicing this will defend it, because they do the same. Which removes all checks and balances. Not that they were ever any strong ones. Systems always protect themselves first.

The history of psychosomatic ideology has been one of disabling all the alarms and all the systems meant to protect against failure like this. It's only natural that it would go to the level where even when they are proven wrong, they can simply say it's still correct, because it's both. This is the foundation of the biopsychosocial model, any and all explanation can be used, so that if one is wrong, any other might do. And really this is the standard that has been built over the decades: the simple possibility that there could be some psychobehavioral explanation is enough. It's how the Norwegian government got to the point where they mandated their chief scientist that it's reasonable for someone to be forced to try every single treatment that can be conceived, even if it takes 100 lifetimes, before being considered disabled.

It effectively creates a system with more power, the mere suspicion of a thought crime is enough for a life sentence, and 30-45 seconds is all it takes, objecting only "proves" the case further, an element of criminal madness, and less than zero responsibility, one where it's preferable to have loads of complete failures in exchange for the simple appearance of possible success. Medicine has effectively created a system where it's preferable for 20 innocent people to get life imprisonment in order to avoid a single criminal mind to go unpunished. Not just that it's acceptable, that it's better this way. Because once someone has been sentenced, well clearly they deserve to be.

 

[Sean]

The history of psychosomatic ideology has been one of disabling all the alarms and all the systems meant to protect against failure like this.

This.

 

[Concentric_Spiral]

Even putting it as "extremely difficult" undersells it. It's completely impossible to prove wrong, because there can always be an opinion of a "functional overlay", the field has been building up the case for years that they can coexist and be impossible to tell apart. This isn't a few rogue ideologues, everyone practicing this will defend it, because they do the same. Which removes all checks and balances. Not that they were ever any strong ones. Systems always protect themselves first.

The history of psychosomatic ideology has been one of disabling all the alarms and all the systems meant to protect against failure like this. It's only natural that it would go to the level where even when they are proven wrong, they can simply say it's still correct, because it's both. This is the foundation of the biopsychosocial model, any and all explanation can be used, so that if one is wrong, any other might do. And really this is the standard that has been built over the decades: the simple possibility that there could be some psychobehavioral explanation is enough. It's how the Norwegian government got to the point where they mandated their chief scientist that it's reasonable for someone to be forced to try every single treatment that can be conceived, even if it takes 100 lifetimes, before being considered disabled.

It effectively creates a system with more power, the mere suspicion of a thought crime is enough for a life sentence, and 30-45 seconds is all it takes, objecting only "proves" the case further, an element of criminal madness, and less than zero responsibility, one where it's preferable to have loads of complete failures in exchange for the simple appearance of possible success. Medicine has effectively created a system where it's preferable for 20 innocent people to get life imprisonment in order to avoid a single criminal mind to go unpunished. Not just that it's acceptable, that it's better this way. Because once someone has been sentenced, well clearly they deserve to be.

The unfalsifiability via 'functional overlay' reminds me of how they kept adding 'epicycles' to the Ptolemaic model of the solar system to try to get it to match observable phenomena. (edit: brain fog xd)

 

[Hutan]

I'm pasting in some examples of cases when the patient's underlying disease becomes so obvious it can no longer be missed, and yet the FND proponents still cannot admit that they made a mistake and caused harm. The result is that people dealing with horrible diseases are denied respectful care. These examples still shock and anger me every time I come back to them.

Any proponent of FND needs to read these examples carefully and reflect on the power they hold over vulnerable people, and the capacity people have to only see what they want to see.

Revising a diagnosis of functional neurological disorder—a case report, 2020, Berry and Weithoff
The text actually used the word 'refine', as in the 'FND diagnosis was refined to progressive supranuclear palsy'.

Functional neurological symptoms as initial presentation of Creutzfeldt-Jakob disease: case series 2022 Gómez-Mayordomo et al
3 cases discussed. Also talks about FND in a whole range of neurodegenerative conditions

And this is the paper that is surely the pinnacle of 'seeing what you want to see'

Another reference in this 2022 paper that I think is worthy of comment:
A Case of Sporadic Creutzfeldt-Jakob Disease Presenting as Conversion Disorder, 2017

It remains unclear whether the patient’s functional symptoms were an early manifestation of sCJD or a cooccurring phenomenon. Functional symptoms have been found in the initial stages of many neurological disorders

This case challenges our perception of conversion disorder as an entirely psychological phenomenon and neurological disease as entirely biological [5]. If disease can exist in an immaterial, “functional” realm, how then can it influence a brain made of matter and mass and produce bodily symptoms? Perhaps the connections are subtler than thought.

 

[Sean]

This case challenges our perception of conversion disorder as an entirely psychological phenomenon and neurological disease as entirely biological [5]. ​

It does no such thing. It challenges the whole concept and practice of conversion disorder (aka FND).

If disease can exist in an immaterial, “functional” realm, how then can it influence a brain made of matter and mass and produce bodily symptoms? Perhaps the connections are subtler than thought.​

Or they don't exist beyond the fevered speculations of FND advocates. Why is that very real possibility not on the table for discussion? Or are they claiming that it is literally impossible for them to be wrong on their, um, interpretation? That it is now just a matter of figuring out the nuts and bolts of the phenomenon, not the possibility of a fundamental mischaracterisation of it and its concept validity in the first place?

Not to mention that by their own definition disease requires demonstrable biophysical substrate, especially structural. Therefore, if it does not exist (or more accurately, has yet to be shown to exist), then there is only illness as misperception and false disease-mimicking internal mental models.

All of which, for the gazillionth time, just reinforces why falsifiability is so central to robust science and our broader understanding of reality.

Who is suffering the misperception problem here? Sure does not look like patients to me.

 

[Arnie Pye]

Support for the term “functional” includes: (1) it is a neutral framing that embraces the causes and mechanistic heterogeneity of this condition within the
biopsychosocial model;

I know what medical staff mean when they say something is functional. So it isn't a neutral term to me. I suspect that "functional" is only neutral if the patient doesn't know what medical staff mean by it.