#functionalneurologicaldisorder — Public Fediverse posts

Two Turkish Women Went Silent After a Shock and Came Back Speaking in Accents They Had Never Learned

A 44-year-old janitor in Turkey, a monolingual native Turkish speaker, was humiliated by her supervisor at work. Her…
#EuropeSays #Turkiye #Türkiye #conversiondisorder #FNDdiagnosis #Foreignaccentsyndrome #functionalneurologicaldisorder #prosody #psychogenicspeech #Speechdisorder #Turkish
https://www.europesays.com/turkiye/46645/

My Request for Correction of Causal Claim for Functional Neurological Symptoms

https://trialbyerror.org/2026/05/25/my-request-for-correction-of-causal-claim-for-functional-neurological-symptoms/

My Request for Correction of Causal Claim for Functional Neurological Symptoms

https://trialbyerror.org/2026/05/25/my-request-for-correction-of-causal-claim-for-functional-neurological-symptoms/

My Request for Correction of Causal Claim for Functional Neurological Symptoms

https://trialbyerror.org/2026/05/25/my-request-for-correction-of-causal-claim-for-functional-neurological-symptoms/

So FND Is Not Only a Brain “Software” Issue After All…

https://trialbyerror.org/2026/05/20/so-fnd-is-not-only-a-brain-software-issue-after-all/

So FND Is Not Only a Brain “Software” Issue After All…

https://trialbyerror.org/2026/05/20/so-fnd-is-not-only-a-brain-software-issue-after-all/

So FND Is Not Only a Brain “Software” Issue After All…

https://trialbyerror.org/2026/05/20/so-fnd-is-not-only-a-brain-software-issue-after-all/

FND + mobility aids = empowerment. For many living with Functional Neurological Disorder, these tools aren’t defeats, they’re freedom. Use what helps you move through the world. 💙

#FND #FunctionalNeurologicalDisorder #MobilityAids #FNDAware #ChronicIllnessSupport

FND + mobility aids = empowerment. For many living with Functional Neurological Disorder, these tools aren’t defeats, they’re freedom. Use what helps you move through the world. 💙

#FND #FunctionalNeurologicalDisorder #MobilityAids #FNDAware #ChronicIllnessSupport

FND + mobility aids = empowerment. For many living with Functional Neurological Disorder, these tools aren’t defeats, they’re freedom. Use what helps you move through the world. 💙

#FND #FunctionalNeurologicalDisorder #MobilityAids #FNDAware #ChronicIllnessSupport

FND + mobility aids = empowerment. For many living with Functional Neurological Disorder, these tools aren’t defeats, they’re freedom. Use what helps you move through the world. 💙

#FND #FunctionalNeurologicalDisorder #MobilityAids #FNDAware #ChronicIllnessSupport

Diagnosed in November 2021, I continue to live with #functionalneurologicaldisorder in ways that surprise, humble, sadden, aggravate, and educate me. (1)

Diagnosed in November 2021, I continue to live with #functionalneurologicaldisorder in ways that surprise, humble, sadden, aggravate, and educate me. (1)

Not all tremors are the same. Understanding the difference between physiologic and functional tremor is key to getting the right treatment and real relief. 🧠✋
#Tremor #Neurology #Telehealth #FunctionalNeurologicalDisorder #MovementDisorders

Not all tremors are the same. Understanding the difference between physiologic and functional tremor is key to getting the right treatment and real relief. 🧠✋
#Tremor #Neurology #Telehealth #FunctionalNeurologicalDisorder #MovementDisorders

Not all tremors are the same. Understanding the difference between physiologic and functional tremor is key to getting the right treatment and real relief. 🧠✋
#Tremor #Neurology #Telehealth #FunctionalNeurologicalDisorder #MovementDisorders

Day 18 of the gin advent calendar. A near-perfect 9.5/10 and a rare moment of agreement with MrsVark.

The blog post also has a few choice words about Functional Neurological Disorder (FND), the bastard thief making MrsVark's life hell. It's cruel to have your own thoughts held hostage by a faulty connection between brain and mouth. FND can fucking do one.

https://theaardvark.co.uk/gin-advent-calendar-day-18-a-near-perfect-gin-and-a-rant-about-fnd.html

#GinAdventCalendar #Gin #FND #FunctionalNeurologicalDisorder #ChronicIllness #FNDAwareness

Day 18 of the gin advent calendar. A near-perfect 9.5/10 and a rare moment of agreement with MrsVark.

The blog post also has a few choice words about Functional Neurological Disorder (FND), the bastard thief making MrsVark's life hell. It's cruel to have your own thoughts held hostage by a faulty connection between brain and mouth. FND can fucking do one.

https://theaardvark.co.uk/gin-advent-calendar-day-18-a-near-perfect-gin-and-a-rant-about-fnd.html

#GinAdventCalendar #Gin #FND #FunctionalNeurologicalDisorder #ChronicIllness #FNDAwareness

Day 18 of the gin advent calendar. A near-perfect 9.5/10 and a rare moment of agreement with MrsVark.

The blog post also has a few choice words about Functional Neurological Disorder (FND), the bastard thief making MrsVark's life hell. It's cruel to have your own thoughts held hostage by a faulty connection between brain and mouth. FND can fucking do one.

https://theaardvark.co.uk/gin-advent-calendar-day-18-a-near-perfect-gin-and-a-rant-about-fnd.html

#GinAdventCalendar #Gin #FND #FunctionalNeurologicalDisorder #ChronicIllness #FNDAwareness

Day 18 of the gin advent calendar. A near-perfect 9.5/10 and a rare moment of agreement with MrsVark.

The blog post also has a few choice words about Functional Neurological Disorder (FND), the bastard thief making MrsVark's life hell. It's cruel to have your own thoughts held hostage by a faulty connection between brain and mouth. FND can fucking do one.

https://theaardvark.co.uk/gin-advent-calendar-day-18-a-near-perfect-gin-and-a-rant-about-fnd.html

#GinAdventCalendar #Gin #FND #FunctionalNeurologicalDisorder #ChronicIllness #FNDAwareness

https://www.europesays.com/ie/187731/ AEW Star Rebel Opens Up About Serious Health Issues #AEW #CryptococcalPneumonia #Éire #FunctionalNeurologicalDisorder #Health #HealthCare #Healthcare #IE #Ireland #LungCancer #Lymphoma #MayoClinic #Rebel

I've been busy over the last few days, trying to catch up with all the posts MrsVark has written for her Wheely Happy Days blog, but which I was too knackered to upload.
The blog is an honest (often brutally so) record of her life as she gets used to, and learns to cope with, life with FND (functional neurological disorder) and CFS (Chronic Fatigue Syndrome).
https://wheelyhappydays.uk/
#FND #FunctionalNeurologicalDisorder #CFS #ChronicFatigueSyndrome
#ChronicIllness

I've been busy over the last few days, trying to catch up with all the posts MrsVark has written for her Wheely Happy Days blog, but which I was too knackered to upload.
The blog is an honest (often brutally so) record of her life as she gets used to, and learns to cope with, life with FND (functional neurological disorder) and CFS (Chronic Fatigue Syndrome).
https://wheelyhappydays.uk/
#FND #FunctionalNeurologicalDisorder #CFS #ChronicFatigueSyndrome
#ChronicIllness

I've been busy over the last few days, trying to catch up with all the posts MrsVark has written for her Wheely Happy Days blog, but which I was too knackered to upload.
The blog is an honest (often brutally so) record of her life as she gets used to, and learns to cope with, life with FND (functional neurological disorder) and CFS (Chronic Fatigue Syndrome).
https://wheelyhappydays.uk/
#FND #FunctionalNeurologicalDisorder #CFS #ChronicFatigueSyndrome
#ChronicIllness

I've been busy over the last few days, trying to catch up with all the posts MrsVark has written for her Wheely Happy Days blog, but which I was too knackered to upload.
The blog is an honest (often brutally so) record of her life as she gets used to, and learns to cope with, life with FND (functional neurological disorder) and CFS (Chronic Fatigue Syndrome).
https://wheelyhappydays.uk/
#FND #FunctionalNeurologicalDisorder #CFS #ChronicFatigueSyndrome
#ChronicIllness

Study Finds Signs of “Functional Limb Weakness” in Patients Not Reporting Actual Limb Weakness

By David Tuller, DrPH

A recently published study about functional neurological disorder (FND) has reported some perplexing data. Of almost 300 patients diagnosed with Long Covid, 100 were identified as demonstrating one or more “positive signs” for “functional limb weakness,” a form of FND. Yet only 14 of those 100 patients reported experiencing limb weakness in the first place; the other 84 did not.

Hm. What does it mean to identify positive signs of functional limb weakness in the absence of reported limb weakness? Who knows? Certainly the investigators themselves make no credible attempt to explain this conundrum.

The study—“Contemporary positive signs of functional limb weakness in post-acute sequelae of SARS-CoV-2: an exploratory analysis of their utility in diagnosis and follow-up”–was published in June by BMJ Neurology Open, a major joural. It is retrospective, with data drawn from the medical records of Long Covid patients who attended a neurology clinic in Tokyo, Japan, from 2021 to 2014. At the clinic, they received comprehensive neurological exams, including testing for positive signs for functional limb weakness. (According to current practice, FND diagnoses require affirmative clinical indications, often referred to as “positive signs” or “rule-in signs,” such as intact reflexes in a limb said to be weak or paralyzed, that are purportedly incompatible with known pathophysiological processes.)

During the exams, the neurologists tested for functional limb weakness using six different signs, described in detail in a supplementary file. Apparently, the discrepancy between the number of patients found to have these positive signs and the much smaller number who actually reported limb weakness during these exams did not raise any particular concerns among the investigators.

Instead, they seem to have assumed that positive signs for functional limb weakness in people with Long COVID indicate cases of FND–even in the absence of evidence that patients are experiencing the relevant symptom. The investigators then suggest that these alleged cases of FND are likely implicated in generating and/or perpetuating Long Covid symptoms like fatigue and headache. “Some of the most common neurological symptoms of long COVID may be caused by FND,” they conclude.

Given that five in six of those with positive signs of functional limb weakness did not report limb weakness, this line of argument is kind of bonkers. The most urgent question arising from this study is: Do these signs mean anything at all? (Several of the signs have long been used in neurology; a couple of them were much more recently identified. As I have previously discussed, the evidence for the overall accuracy of these various signs is shaky.)

I suppose it is possible that some patients in the study might not have been that specific and might have referred to limb weakness as “fatigue.” But it seems highly unlikely this would have occurred in 84 out of 100 cases. After all, these patients underwent comprehensive neurological exams that included tests for functional limb weakness. Presumably, the neurologists conducting these exams asked questions that would have, or should have, elicited an accurate accounting of a distinctive symptom like limb weakness.

FND is the current name for the psychiatric condition formerly called conversion disorder, in which psychological distress was said to have been “converted” into physical symptoms. Experts in the FND field assert categorically that is a “brain network” disorder, but that is a theory, not a fact. The reality is that the etiology and pathophysiological processes causing the symptoms remain unknown. What is clear is that people with FND suffer from extremely distressing and disabling symptoms that resist easy explanation. Those with the condition are ill-served by research that fails to abide by basic rules of scientific reasoning.

My UC Berkeley colleague, infectious disease physician and professor emeritus John Swartzberg, shared my low opinion of this piece of work. That this deeply flawed paper passed through a BMJ journal’s peer review process, he said, was “very disappointing.”

The paper is marred by sentences like this: “Assuming that patients with positive signs had FND, the prevalence of FND coexisting with long COVID is likely to not depend on which variant of COVID patients were infected with but solely on the number of patients infected with COVID-19, as observed in this study.” Since those with positive signs of functional limb weakness were much more likely not to have reported any limb weakness than to have reported it, the assumption that “patients with positive signs had FND” is hard to justify. And any further claims built on that unjustifiable assumption cannot be taken seriously.

And there are passages in which, given the uninterpretable results on the positive signs, the argument reads like a parody:

“In summary, our study showed that long COVID, accompanied by positive signs, is not rare and that this phenomenon indicates the possibility of the coexistence of long COVID and FND. Therefore, some patients with long COVID may present with symptoms of FND. If positive signs are observed in long COVID patients, they are a useful indicator of the coexistence of FND in those with long COVID.”

The paper is a house of cards built on unwarranted assertions and pirouettes of logic. (I’ve addressed a core concern in this post but not the only one.) In any event, BMJ journals have not distinguished themselves when it comes to ME/CFS and Long COVID. This latest problematic publication is not remotely surprising.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder #LongCovid

Study Finds Signs of “Functional Limb Weakness” in Patients Not Reporting Actual Limb Weakness

By David Tuller, DrPH

A recently published study about functional neurological disorder (FND) has reported some perplexing data. Of almost 300 patients diagnosed with Long Covid, 100 were identified as demonstrating one or more “positive signs” for “functional limb weakness,” a form of FND. Yet only 14 of those 100 patients reported experiencing limb weakness in the first place; the other 84 did not.

Hm. What does it mean to identify positive signs of functional limb weakness in the absence of reported limb weakness? Who knows? Certainly the investigators themselves make no credible attempt to explain this conundrum.

The study—“Contemporary positive signs of functional limb weakness in post-acute sequelae of SARS-CoV-2: an exploratory analysis of their utility in diagnosis and follow-up”–was published in June by BMJ Neurology Open, a major joural. It is retrospective, with data drawn from the medical records of Long Covid patients who attended a neurology clinic in Tokyo, Japan, from 2021 to 2014. At the clinic, they received comprehensive neurological exams, including testing for positive signs for functional limb weakness. (According to current practice, FND diagnoses require affirmative clinical indications, often referred to as “positive signs” or “rule-in signs,” such as intact reflexes in a limb said to be weak or paralyzed, that are purportedly incompatible with known pathophysiological processes.)

During the exams, the neurologists tested for functional limb weakness using six different signs, described in detail in a supplementary file. Apparently, the discrepancy between the number of patients found to have these positive signs and the much smaller number who actually reported limb weakness during these exams did not raise any particular concerns among the investigators.

Instead, they seem to have assumed that positive signs for functional limb weakness in people with Long COVID indicate cases of FND–even in the absence of evidence that patients are experiencing the relevant symptom. The investigators then suggest that these alleged cases of FND are likely implicated in generating and/or perpetuating Long Covid symptoms like fatigue and headache. “Some of the most common neurological symptoms of long COVID may be caused by FND,” they conclude.

Given that five in six of those with positive signs of functional limb weakness did not report limb weakness, this line of argument is kind of bonkers. The most urgent question arising from this study is: Do these signs mean anything at all? (Several of the signs have long been used in neurology; a couple of them were much more recently identified. As I have previously discussed, the evidence for the overall accuracy of these various signs is shaky.)

I suppose it is possible that some patients in the study might not have been that specific and might have referred to limb weakness as “fatigue.” But it seems highly unlikely this would have occurred in 84 out of 100 cases. After all, these patients underwent comprehensive neurological exams that included tests for functional limb weakness. Presumably, the neurologists conducting these exams asked questions that would have, or should have, elicited an accurate accounting of a distinctive symptom like limb weakness.

FND is the current name for the psychiatric condition formerly called conversion disorder, in which psychological distress was said to have been “converted” into physical symptoms. Experts in the FND field assert categorically that is a “brain network” disorder, but that is a theory, not a fact. The reality is that the etiology and pathophysiological processes causing the symptoms remain unknown. What is clear is that people with FND suffer from extremely distressing and disabling symptoms that resist easy explanation. Those with the condition are ill-served by research that fails to abide by basic rules of scientific reasoning.

My UC Berkeley colleague, infectious disease physician and professor emeritus John Swartzberg, shared my low opinion of this piece of work. That this deeply flawed paper passed through a BMJ journal’s peer review process, he said, was “very disappointing.”

The paper is marred by sentences like this: “Assuming that patients with positive signs had FND, the prevalence of FND coexisting with long COVID is likely to not depend on which variant of COVID patients were infected with but solely on the number of patients infected with COVID-19, as observed in this study.” Since those with positive signs of functional limb weakness were much more likely not to have reported any limb weakness than to have reported it, the assumption that “patients with positive signs had FND” is hard to justify. And any further claims built on that unjustifiable assumption cannot be taken seriously.

And there are passages in which, given the uninterpretable results on the positive signs, the argument reads like a parody:

“In summary, our study showed that long COVID, accompanied by positive signs, is not rare and that this phenomenon indicates the possibility of the coexistence of long COVID and FND. Therefore, some patients with long COVID may present with symptoms of FND. If positive signs are observed in long COVID patients, they are a useful indicator of the coexistence of FND in those with long COVID.”

The paper is a house of cards built on unwarranted assertions and pirouettes of logic. (I’ve addressed a core concern in this post but not the only one.) In any event, BMJ journals have not distinguished themselves when it comes to ME/CFS and Long COVID. This latest problematic publication is not remotely surprising.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder #LongCovid

Study Finds Signs of “Functional Limb Weakness” in Patients Not Reporting Actual Limb Weakness

By David Tuller, DrPH

A recently published study about functional neurological disorder (FND) has reported some perplexing data. Of almost 300 patients diagnosed with Long Covid, 100 were identified as demonstrating one or more “positive signs” for “functional limb weakness,” a form of FND. Yet only 14 of those 100 patients reported experiencing limb weakness in the first place; the other 84 did not.

Hm. What does it mean to identify positive signs of functional limb weakness in the absence of reported limb weakness? Who knows? Certainly the investigators themselves make no credible attempt to explain this conundrum.

The study—“Contemporary positive signs of functional limb weakness in post-acute sequelae of SARS-CoV-2: an exploratory analysis of their utility in diagnosis and follow-up”–was published in June by BMJ Neurology Open, a major joural. It is retrospective, with data drawn from the medical records of Long Covid patients who attended a neurology clinic in Tokyo, Japan, from 2021 to 2014. At the clinic, they received comprehensive neurological exams, including testing for positive signs for functional limb weakness. (According to current practice, FND diagnoses require affirmative clinical indications, often referred to as “positive signs” or “rule-in signs,” such as intact reflexes in a limb said to be weak or paralyzed, that are purportedly incompatible with known pathophysiological processes.)

During the exams, the neurologists tested for functional limb weakness using six different signs, described in detail in a supplementary file. Apparently, the discrepancy between the number of patients found to have these positive signs and the much smaller number who actually reported limb weakness during these exams did not raise any particular concerns among the investigators.

Instead, they seem to have assumed that positive signs for functional limb weakness in people with Long COVID indicate cases of FND–even in the absence of evidence that patients are experiencing the relevant symptom. The investigators then suggest that these alleged cases of FND are likely implicated in generating and/or perpetuating Long Covid symptoms like fatigue and headache. “Some of the most common neurological symptoms of long COVID may be caused by FND,” they conclude.

Given that five in six of those with positive signs of functional limb weakness did not report limb weakness, this line of argument is kind of bonkers. The most urgent question arising from this study is: Do these signs mean anything at all? (Several of the signs have long been used in neurology; a couple of them were much more recently identified. As I have previously discussed, the evidence for the overall accuracy of these various signs is shaky.)

I suppose it is possible that some patients in the study might not have been that specific and might have referred to limb weakness as “fatigue.” But it seems highly unlikely this would have occurred in 84 out of 100 cases. After all, these patients underwent comprehensive neurological exams that included tests for functional limb weakness. Presumably, the neurologists conducting these exams asked questions that would have, or should have, elicited an accurate accounting of a distinctive symptom like limb weakness.

FND is the current name for the psychiatric condition formerly called conversion disorder, in which psychological distress was said to have been “converted” into physical symptoms. Experts in the FND field assert categorically that is a “brain network” disorder, but that is a theory, not a fact. The reality is that the etiology and pathophysiological processes causing the symptoms remain unknown. What is clear is that people with FND suffer from extremely distressing and disabling symptoms that resist easy explanation. Those with the condition are ill-served by research that fails to abide by basic rules of scientific reasoning.

My UC Berkeley colleague, infectious disease physician and professor emeritus John Swartzberg, shared my low opinion of this piece of work. That this deeply flawed paper passed through a BMJ journal’s peer review process, he said, was “very disappointing.”

The paper is marred by sentences like this: “Assuming that patients with positive signs had FND, the prevalence of FND coexisting with long COVID is likely to not depend on which variant of COVID patients were infected with but solely on the number of patients infected with COVID-19, as observed in this study.” Since those with positive signs of functional limb weakness were much more likely not to have reported any limb weakness than to have reported it, the assumption that “patients with positive signs had FND” is hard to justify. And any further claims built on that unjustifiable assumption cannot be taken seriously.

And there are passages in which, given the uninterpretable results on the positive signs, the argument reads like a parody:

“In summary, our study showed that long COVID, accompanied by positive signs, is not rare and that this phenomenon indicates the possibility of the coexistence of long COVID and FND. Therefore, some patients with long COVID may present with symptoms of FND. If positive signs are observed in long COVID patients, they are a useful indicator of the coexistence of FND in those with long COVID.”

The paper is a house of cards built on unwarranted assertions and pirouettes of logic. (I’ve addressed a core concern in this post but not the only one.) In any event, BMJ journals have not distinguished themselves when it comes to ME/CFS and Long COVID. This latest problematic publication is not remotely surprising.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder #LongCovid

Null Results in Physiotherapy Trial for Functional Motor Disorder

By David Tuller, DrPH

*This is a crowdfunding month at University of California, Berkeley. If you appreciate my work and would like to make a donation (tax-deductible to US taxpayers) to the university in support of my position, here’s the link: https://crowdfund.berkeley.edu/project/46120

It must be tough for investigators when a major study seeking to assess the effectiveness of an intervention for a challenging condition yields null results. That’s what happened in 2019 with a trial of rituximab for ME/CFS, published in Annals of Internal Medicine. Findings from earlier research had suggested that rituximab, a drug used to treat autoimmune diseases, might have an impact on ME/CFS. However, the trial results did not support the hypothesis, forcing the investigators to revisit their notions about the mechanisms driving the disease.

Last year, a large trial for functional motor disorder (FMD), a subcategory of functional neurological disorder (FND), reported similarly disappointing news. In a paper in The Lancet Neurology, published in July, the investigators of the trial, nicknamed Physio4FMD, reported null results for specialized physiotherapy on the primary outcome–self-reported physical function at 12 months. While those who received the Physio4FMD intervention had slightly better scores on this measure than those who received treatment as usual (TAU), the results were neither statistically nor clinically significant.

(The lead author posted a thread about the findings here.)

In such cases, investigators are often in the somewhat thankless position of having to publish further analyses, trying to find some silver linings even though their intervention has already failed its most important test. Since last month, the Physio4FMD team has published two additional papers: a look at factors predicting outcomes, and a cost-effectiveness analysis. (I might get around to looking at those in a subsequent post.)

FND, formerly called conversion disorder, is the current term for a category of neurological symptoms that do not fall within established disease categories. The sub-group of functional motor disorder includes arm or leg weakness and paralysis, gait disorders, and the like. These conditions, whatever their cause, can be chronic, seriously disabling, and resistant to treatment. In the past, they were generally viewed as psychiatric conditions. In recent years, FND experts have categorized them as “brain network” disorders. In reality, their etiology remains unknown.

This is the second time in recent years that a high-profile FND treatment trial produced null results for its primary outcome. In 2020, the CODES trial for psychogenic non-epileptic or “dissociative” seizures, another subcategory of FND, reported that cognitive behavior therapy was no more effective than standard care in leading to seizure reduction at 12 months. In that case, FND experts argued after-the-fact that seizure reduction was the wrong primary outcome and that “quality-of-life” measures were more important.

Just as CODES was the largest trial of dissociative seizures, this new FND study–“Specialist physiotherapy for functional motor disorder in England and Scotland (Physio4FMD): a pragmatic, multicentre, phase 3 randomised controlled trial”–represented a first for the field. Noted the paper: “To the best of our knowledge, Physio4FMD is the first fully powered randomised controlled trial of a physical therapy-based intervention for functional motor disorder and is the largest randomised study of people with functional motor disorder published to date.”

The trial’s primary analysis included 241 participants from 11 hospitals in Scotland and England, with 138 assigned to the Physio4FMD intervention and 103 to TAU. The latter consisted of whatever treatment the participants received, or didn’t receive, after referral to the local National Health Service (NHS) neurological physiotherapy service. The intervention included nine sessions over three weeks, with a final session three months later. (Recruitment began in 2018 but was interrupted by the COVID-19 pandemic. The paper goes to substantial lengths to explain how the team addressed these challenging circumstances, including in the statistical analyses.)

As described in the paper, the Physio4FMD intervention sought to focus on the factors presumed to be driving the symptoms, such as paying excessive attention to symptoms, and had three broad goals: “to help patients understand their symptoms; to retrain movement with redirection of attention away from focusing on their body; and to develop self-­management skills.” The approach had undergone extensive development in the years before the trial. As noted, “the protocol builds on expert consensus recommendations for physiotherapy for functional motor disorder and was tested with promising outcomes in a prospective cohort study and a randomised feasibility study.”

The trial was unblinded and relied on subjective outcomes—a study design that generates an unknown amount of bias, for any number of reasons. In such cases, modestly positive findings are as likely to reflect the bias inherent in the design as any genuine impact of the intervention.

**********

Poor results on the primary outcome

In any event, the intervention did not produce the expected results. The primary outcome, the SF-36, is a frequently used measure for self-reported physical function. As described in the paper, it “includes ten questions for participants to self-­rate their degree of limitation when attempting vigorous activities (eg, running or lifting heavy objects), moderate activities (eg, moving a table or pushing a vacuum cleaner), carrying groceries, climbing stairs, walking various distances, washing, and dressing.”

Scores on the SF-36 range from 0 to 100. Higher scores represent better physical function. A score of 65 or below, for example, was considered disabled enough to be able to enter the PACE trial, which purported to prove that psycho-behavioral interventions could cure ME/CFS. In the Physio4FMD trial, the average scores at baseline were 26 and 31, respectively, for the intervention and TAU groups. That is very, very disabled. At 12 months, both groups averaged just over 37—still very, very disabled.

Besides not being statistically significant, the mean difference between the two groups at 12 months on the SF-36 was also, at 3.5 points, below the threshold considered clinically significant. On the SF-36, the threshold for a difference to be considered clinically significant is 10 points.

Among the many secondary outcomes, the Physio4FMD intervention arm scored better than the TAU arm on an overall rating of symptom improvement and on treatment satisfaction. But many other secondary measures had null results. As the investigators noted in the limitations section, given the number of secondary outcomes, some might have been found to be statistically significant by chance, and the analysis did not include the extra tests designed to minimize this possibility.

The rating of symptom improvement, called the clinical global impression of improvement scale (CGI­-I), is much briefer than the SF-36. In the CGI-I, as the study explained, “participants rate their perception of improvement in answer to the question, ‘After physiotherapy, the problem with my movement is…’ with the responses either ‘much improved,’ ‘improved,’ ‘no change,’ ‘worse,’ or ‘much worse.’” The answers thus provide no indication of the respondent’s level of disability in relation to others—just in relation to their own prior subjective state.

Like the CGI-I, the SF-36 is self-reported and therefore subject to biases related to that status. Unlike the CGI-I, it covers a range of specific activities and requires the respondent to consider each one separately. With its 100-point scoring, the SF-36 allows for easy comparison of results with other populations. In the Physio4FMD study, no matter what participants reported on the CGI-I, they remained severely disabled overall, according to the primary outcome.

In summing up, the investigators concluded that,“taken together, the subjective improvements in symptom ratings along with the very high levels of satisfaction with treatment, suggest that specialist physiotherapy could be a valued and safe treatment option for some people with functional motor disorder.”

Suggesting that a treatment “could be” an option for “some” patients is not saying much. As for the reports on symptom improvement and treatment satisfaction, it shouldn’t be surprising that patients who receive care from compassionate clinicians are more likely to answer questionnaires positively than patients who don’t receive the same level of care. These responses should not therefore be interpreted to mean the intervention is effective–especially given the poor results for the more comprehensive and thorough assessment provided by the SF-36, the primary outcome.

The bottom line, per the SF-36 data, is that the patients in this trial remained extremely debilitated, whether they received the Physio4FMD intervention or physiotherapy at a local NHS service. That’s the take-home message here.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder

Null Results in Physiotherapy Trial for Functional Motor Disorder

By David Tuller, DrPH

*This is a crowdfunding month at University of California, Berkeley. If you appreciate my work and would like to make a donation (tax-deductible to US taxpayers) to the university in support of my position, here’s the link: https://crowdfund.berkeley.edu/project/46120

It must be tough for investigators when a major study seeking to assess the effectiveness of an intervention for a challenging condition yields null results. That’s what happened in 2019 with a trial of rituximab for ME/CFS, published in Annals of Internal Medicine. Findings from earlier research had suggested that rituximab, a drug used to treat autoimmune diseases, might have an impact on ME/CFS. However, the trial results did not support the hypothesis, forcing the investigators to revisit their notions about the mechanisms driving the disease.

Last year, a large trial for functional motor disorder (FMD), a subcategory of functional neurological disorder (FND), reported similarly disappointing news. In a paper in The Lancet Neurology, published in July, the investigators of the trial, nicknamed Physio4FMD, reported null results for specialized physiotherapy on the primary outcome–self-reported physical function at 12 months. While those who received the Physio4FMD intervention had slightly better scores on this measure than those who received treatment as usual (TAU), the results were neither statistically nor clinically significant.

(The lead author posted a thread about the findings here.)

In such cases, investigators are often in the somewhat thankless position of having to publish further analyses, trying to find some silver linings even though their intervention has already failed its most important test. Since last month, the Physio4FMD team has published two additional papers: a look at factors predicting outcomes, and a cost-effectiveness analysis. (I might get around to looking at those in a subsequent post.)

FND, formerly called conversion disorder, is the current term for a category of neurological symptoms that do not fall within established disease categories. The sub-group of functional motor disorder includes arm or leg weakness and paralysis, gait disorders, and the like. These conditions, whatever their cause, can be chronic, seriously disabling, and resistant to treatment. In the past, they were generally viewed as psychiatric conditions. In recent years, FND experts have categorized them as “brain network” disorders. In reality, their etiology remains unknown.

This is the second time in recent years that a high-profile FND treatment trial produced null results for its primary outcome. In 2020, the CODES trial for psychogenic non-epileptic or “dissociative” seizures, another subcategory of FND, reported that cognitive behavior therapy was no more effective than standard care in leading to seizure reduction at 12 months. In that case, FND experts argued after-the-fact that seizure reduction was the wrong primary outcome and that “quality-of-life” measures were more important.

Just as CODES was the largest trial of dissociative seizures, this new FND study–“Specialist physiotherapy for functional motor disorder in England and Scotland (Physio4FMD): a pragmatic, multicentre, phase 3 randomised controlled trial”–represented a first for the field. Noted the paper: “To the best of our knowledge, Physio4FMD is the first fully powered randomised controlled trial of a physical therapy-based intervention for functional motor disorder and is the largest randomised study of people with functional motor disorder published to date.”

The trial’s primary analysis included 241 participants from 11 hospitals in Scotland and England, with 138 assigned to the Physio4FMD intervention and 103 to TAU. The latter consisted of whatever treatment the participants received, or didn’t receive, after referral to the local National Health Service (NHS) neurological physiotherapy service. The intervention included nine sessions over three weeks, with a final session three months later. (Recruitment began in 2018 but was interrupted by the COVID-19 pandemic. The paper goes to substantial lengths to explain how the team addressed these challenging circumstances, including in the statistical analyses.)

As described in the paper, the Physio4FMD intervention sought to focus on the factors presumed to be driving the symptoms, such as paying excessive attention to symptoms, and had three broad goals: “to help patients understand their symptoms; to retrain movement with redirection of attention away from focusing on their body; and to develop self-­management skills.” The approach had undergone extensive development in the years before the trial. As noted, “the protocol builds on expert consensus recommendations for physiotherapy for functional motor disorder and was tested with promising outcomes in a prospective cohort study and a randomised feasibility study.”

The trial was unblinded and relied on subjective outcomes—a study design that generates an unknown amount of bias, for any number of reasons. In such cases, modestly positive findings are as likely to reflect the bias inherent in the design as any genuine impact of the intervention.

**********

Poor results on the primary outcome

In any event, the intervention did not produce the expected results. The primary outcome, the SF-36, is a frequently used measure for self-reported physical function. As described in the paper, it “includes ten questions for participants to self-­rate their degree of limitation when attempting vigorous activities (eg, running or lifting heavy objects), moderate activities (eg, moving a table or pushing a vacuum cleaner), carrying groceries, climbing stairs, walking various distances, washing, and dressing.”

Scores on the SF-36 range from 0 to 100. Higher scores represent better physical function. A score of 65 or below, for example, was considered disabled enough to be able to enter the PACE trial, which purported to prove that psycho-behavioral interventions could cure ME/CFS. In the Physio4FMD trial, the average scores at baseline were 26 and 31, respectively, for the intervention and TAU groups. That is very, very disabled. At 12 months, both groups averaged just over 37—still very, very disabled.

Besides not being statistically significant, the mean difference between the two groups at 12 months on the SF-36 was also, at 3.5 points, below the threshold considered clinically significant. On the SF-36, the threshold for a difference to be considered clinically significant is 10 points.

Among the many secondary outcomes, the Physio4FMD intervention arm scored better than the TAU arm on an overall rating of symptom improvement and on treatment satisfaction. But many other secondary measures had null results. As the investigators noted in the limitations section, given the number of secondary outcomes, some might have been found to be statistically significant by chance, and the analysis did not include the extra tests designed to minimize this possibility.

The rating of symptom improvement, called the clinical global impression of improvement scale (CGI­-I), is much briefer than the SF-36. In the CGI-I, as the study explained, “participants rate their perception of improvement in answer to the question, ‘After physiotherapy, the problem with my movement is…’ with the responses either ‘much improved,’ ‘improved,’ ‘no change,’ ‘worse,’ or ‘much worse.’” The answers thus provide no indication of the respondent’s level of disability in relation to others—just in relation to their own prior subjective state.

Like the CGI-I, the SF-36 is self-reported and therefore subject to biases related to that status. Unlike the CGI-I, it covers a range of specific activities and requires the respondent to consider each one separately. With its 100-point scoring, the SF-36 allows for easy comparison of results with other populations. In the Physio4FMD study, no matter what participants reported on the CGI-I, they remained severely disabled overall, according to the primary outcome.

In summing up, the investigators concluded that,“taken together, the subjective improvements in symptom ratings along with the very high levels of satisfaction with treatment, suggest that specialist physiotherapy could be a valued and safe treatment option for some people with functional motor disorder.”

Suggesting that a treatment “could be” an option for “some” patients is not saying much. As for the reports on symptom improvement and treatment satisfaction, it shouldn’t be surprising that patients who receive care from compassionate clinicians are more likely to answer questionnaires positively than patients who don’t receive the same level of care. These responses should not therefore be interpreted to mean the intervention is effective–especially given the poor results for the more comprehensive and thorough assessment provided by the SF-36, the primary outcome.

The bottom line, per the SF-36 data, is that the patients in this trial remained extremely debilitated, whether they received the Physio4FMD intervention or physiotherapy at a local NHS service. That’s the take-home message here.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder

Null Results in Physiotherapy Trial for Functional Motor Disorder

By David Tuller, DrPH

*This is a crowdfunding month at University of California, Berkeley. If you appreciate my work and would like to make a donation (tax-deductible to US taxpayers) to the university in support of my position, here’s the link: https://crowdfund.berkeley.edu/project/46120

It must be tough for investigators when a major study seeking to assess the effectiveness of an intervention for a challenging condition yields null results. That’s what happened in 2019 with a trial of rituximab for ME/CFS, published in Annals of Internal Medicine. Findings from earlier research had suggested that rituximab, a drug used to treat autoimmune diseases, might have an impact on ME/CFS. However, the trial results did not support the hypothesis, forcing the investigators to revisit their notions about the mechanisms driving the disease.

Last year, a large trial for functional motor disorder (FMD), a subcategory of functional neurological disorder (FND), reported similarly disappointing news. In a paper in The Lancet Neurology, published in July, the investigators of the trial, nicknamed Physio4FMD, reported null results for specialized physiotherapy on the primary outcome–self-reported physical function at 12 months. While those who received the Physio4FMD intervention had slightly better scores on this measure than those who received treatment as usual (TAU), the results were neither statistically nor clinically significant.

(The lead author posted a thread about the findings here.)

In such cases, investigators are often in the somewhat thankless position of having to publish further analyses, trying to find some silver linings even though their intervention has already failed its most important test. Since last month, the Physio4FMD team has published two additional papers: a look at factors predicting outcomes, and a cost-effectiveness analysis. (I might get around to looking at those in a subsequent post.)

FND, formerly called conversion disorder, is the current term for a category of neurological symptoms that do not fall within established disease categories. The sub-group of functional motor disorder includes arm or leg weakness and paralysis, gait disorders, and the like. These conditions, whatever their cause, can be chronic, seriously disabling, and resistant to treatment. In the past, they were generally viewed as psychiatric conditions. In recent years, FND experts have categorized them as “brain network” disorders. In reality, their etiology remains unknown.

This is the second time in recent years that a high-profile FND treatment trial produced null results for its primary outcome. In 2020, the CODES trial for psychogenic non-epileptic or “dissociative” seizures, another subcategory of FND, reported that cognitive behavior therapy was no more effective than standard care in leading to seizure reduction at 12 months. In that case, FND experts argued after-the-fact that seizure reduction was the wrong primary outcome and that “quality-of-life” measures were more important.

Just as CODES was the largest trial of dissociative seizures, this new FND study–“Specialist physiotherapy for functional motor disorder in England and Scotland (Physio4FMD): a pragmatic, multicentre, phase 3 randomised controlled trial”–represented a first for the field. Noted the paper: “To the best of our knowledge, Physio4FMD is the first fully powered randomised controlled trial of a physical therapy-based intervention for functional motor disorder and is the largest randomised study of people with functional motor disorder published to date.”

The trial’s primary analysis included 241 participants from 11 hospitals in Scotland and England, with 138 assigned to the Physio4FMD intervention and 103 to TAU. The latter consisted of whatever treatment the participants received, or didn’t receive, after referral to the local National Health Service (NHS) neurological physiotherapy service. The intervention included nine sessions over three weeks, with a final session three months later. (Recruitment began in 2018 but was interrupted by the COVID-19 pandemic. The paper goes to substantial lengths to explain how the team addressed these challenging circumstances, including in the statistical analyses.)

As described in the paper, the Physio4FMD intervention sought to focus on the factors presumed to be driving the symptoms, such as paying excessive attention to symptoms, and had three broad goals: “to help patients understand their symptoms; to retrain movement with redirection of attention away from focusing on their body; and to develop self-­management skills.” The approach had undergone extensive development in the years before the trial. As noted, “the protocol builds on expert consensus recommendations for physiotherapy for functional motor disorder and was tested with promising outcomes in a prospective cohort study and a randomised feasibility study.”

The trial was unblinded and relied on subjective outcomes—a study design that generates an unknown amount of bias, for any number of reasons. In such cases, modestly positive findings are as likely to reflect the bias inherent in the design as any genuine impact of the intervention.

**********

Poor results on the primary outcome

In any event, the intervention did not produce the expected results. The primary outcome, the SF-36, is a frequently used measure for self-reported physical function. As described in the paper, it “includes ten questions for participants to self-­rate their degree of limitation when attempting vigorous activities (eg, running or lifting heavy objects), moderate activities (eg, moving a table or pushing a vacuum cleaner), carrying groceries, climbing stairs, walking various distances, washing, and dressing.”

Scores on the SF-36 range from 0 to 100. Higher scores represent better physical function. A score of 65 or below, for example, was considered disabled enough to be able to enter the PACE trial, which purported to prove that psycho-behavioral interventions could cure ME/CFS. In the Physio4FMD trial, the average scores at baseline were 26 and 31, respectively, for the intervention and TAU groups. That is very, very disabled. At 12 months, both groups averaged just over 37—still very, very disabled.

Besides not being statistically significant, the mean difference between the two groups at 12 months on the SF-36 was also, at 3.5 points, below the threshold considered clinically significant. On the SF-36, the threshold for a difference to be considered clinically significant is 10 points.

Among the many secondary outcomes, the Physio4FMD intervention arm scored better than the TAU arm on an overall rating of symptom improvement and on treatment satisfaction. But many other secondary measures had null results. As the investigators noted in the limitations section, given the number of secondary outcomes, some might have been found to be statistically significant by chance, and the analysis did not include the extra tests designed to minimize this possibility.

The rating of symptom improvement, called the clinical global impression of improvement scale (CGI­-I), is much briefer than the SF-36. In the CGI-I, as the study explained, “participants rate their perception of improvement in answer to the question, ‘After physiotherapy, the problem with my movement is…’ with the responses either ‘much improved,’ ‘improved,’ ‘no change,’ ‘worse,’ or ‘much worse.’” The answers thus provide no indication of the respondent’s level of disability in relation to others—just in relation to their own prior subjective state.

Like the CGI-I, the SF-36 is self-reported and therefore subject to biases related to that status. Unlike the CGI-I, it covers a range of specific activities and requires the respondent to consider each one separately. With its 100-point scoring, the SF-36 allows for easy comparison of results with other populations. In the Physio4FMD study, no matter what participants reported on the CGI-I, they remained severely disabled overall, according to the primary outcome.

In summing up, the investigators concluded that,“taken together, the subjective improvements in symptom ratings along with the very high levels of satisfaction with treatment, suggest that specialist physiotherapy could be a valued and safe treatment option for some people with functional motor disorder.”

Suggesting that a treatment “could be” an option for “some” patients is not saying much. As for the reports on symptom improvement and treatment satisfaction, it shouldn’t be surprising that patients who receive care from compassionate clinicians are more likely to answer questionnaires positively than patients who don’t receive the same level of care. These responses should not therefore be interpreted to mean the intervention is effective–especially given the poor results for the more comprehensive and thorough assessment provided by the SF-36, the primary outcome.

The bottom line, per the SF-36 data, is that the patients in this trial remained extremely debilitated, whether they received the Physio4FMD intervention or physiotherapy at a local NHS service. That’s the take-home message here.

(View the original post at virology.ws)

#FND #functionalNeurologicalDisorder

Experience: ‘I woke up with a Welsh accent’ | Life and style | The Guardian
https://www.theguardian.com/lifeandstyle/article/2024/may/24/experience-i-woke-up-with-a-welsh-accent

#FunctionalNeurologicalDisorder
#FND
#ForeignAccentSyndrome

Experience: ‘I woke up with a Welsh accent’ | Life and style | The Guardian
https://www.theguardian.com/lifeandstyle/article/2024/may/24/experience-i-woke-up-with-a-welsh-accent

#FunctionalNeurologicalDisorder
#FND
#ForeignAccentSyndrome

Experience: ‘I woke up with a Welsh accent’ | Life and style | The Guardian
https://www.theguardian.com/lifeandstyle/article/2024/may/24/experience-i-woke-up-with-a-welsh-accent

#FunctionalNeurologicalDisorder
#FND
#ForeignAccentSyndrome

By David Tuller, DrPH

In two recent posts, here and here, I wrote about our letter on inflated prevalence claims for functional neurological disorder (FND) and about the response from the authors of the study we criticized. The 2021 article in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda,” asserted that FND was the second-most-common diagnosis at outpatient neurology clinics. The article cited a major 2010 study, Stone et al, in support of this assertion.

In that study, however, only 209 of 3781 participants—that is, 5.5%–were diagnosed with what could now be called FND. That placed FND way down the list of diagnoses from #2–a claim that rested on the parallel and frequently repeated assertion that the prevalence in the 2010 study was 16%.

The authors of the 2021 paper responded to our letter with non-responses, evasions and irrelevancies, in the process documenting the validity of the criticism. I already knew the gist of what their response would be because the popular website neurosymptoms.org had posted a similar accounting of the 2010 study in its FAQ section. (More on that below.)

Neurosymptoms.org is a website created and maintained by Professor Jon Stone, a neurologist at the University of Edinburgh and one of the leading advocates for reframing the Freudian construct of conversion disorder as FND. He was also a co-author of the 2021 paper in NeuroImage: Clinical that was the subject of our letter questioning the prevalence claims. Not incidentally, Professor Stone is a junior colleague of lead PACE investigator Professor Michael Sharpe and the lead author of Stone et al, the 2010 paper whose findings on FND prevalence have been misrepresented since its publication. Professor Sharpe was the senior author of Stone et al.

Adding to the confusion, Professor Stone himself has elsewhere endorsed the lower prevalence for FND. In our letter, we noted a 2023 paper that, citing the same body of research, referred to a prevalence of 5.4%; Professor Stone was a co-author of that 2023 paper as well. (For unexplained reasons, Professor Stone and colleagues have calculated 209/3781 as 5.4% rather than 5.5%.) It is of course the case that the prevalence of FND, as calculated from the SNSS, cannot be both 5.5% (or 5.4%) and 16%.

So let’s see how neurosymptoms.org now describes this seminal study in its FAQ section on prevalence.(I’ve posted about this before, but it’s relevant now and bears repeating.) The language certainly confirms the concerns about misrepresentation expressed in our letter to NeuroImage: Clinical. Here’s neurosymptoms.org:

“In another older study of 3781 new appointments across Scotland, there were 209 patients who had clear FND and another 200 who had additional functional disorder diagnoses including dizziness and cognitive symptoms which could also be included now within FND. Other patients presented with diagnoses like migraine, but the neurologists thought the main issue was an associated functional disorder.”

This statement is evidence of the validity of our criticism. Only 209 out of 3781 participants in the study had “clear FND.” These were patients who were diagnosed with symptoms consistent with conversion disorder, the former name for FND. This statement about “clear FND” is a definitive acknowledgement that the prevalence of FND in this study was not 16%, and that FND was not the second-most-common diagnosis.

Then the passage cites “dizziness and cognitive symptoms,” arguing that these cases might conform to current definitions of FND. But that’s all post-hoc speculation and not grounded in any evidence from the study. Furthermore, having migraine or other symptoms in combination with an “associated functional disorder” is not the same as having FND. And the passage continues: “So, anything from 6-16% of patients could be said to have a functional disorder depending on how that was defined. The upper limit of that estimate would make it the second commonest reason to see a neurologist.”

This statement is a far cry from a declarative assertion that FND is the second-most-common reason to see a neurologist—the problematic assertion included in the 2021 paper in NeuroImage: Clnical. I’ve been criticized for criticizing FND experts without being a neurologist or neuroscientist or biologist or whatever. But I understand English well enough to know that there’s a really big difference in meaning between “16% of patients have FND” and “6-16% of patients could be said to have a functional disorder depending on how that was defined.”

Professor Stone—and his many distinguished colleagues in the FND field—obviously know there’s a difference as well. They have nonetheless chosen to pretend otherwise in the interests of maximizing reported prevalence rates. Anyone who has knowingly signed on to this blatant distortion of these seminal findings is evidently missing an integrity chip. It is hard to take anything such investigators write at face value—and that’s why I don’t.

https://trialbyerror.org/2024/02/13/leading-fnd-site-confirms-criticisms-on-prevalence-outlined-in-our-letter-to-neurology-journal/

#2 #FND #functionalNeurologicalDisorder #JonStone

Annual check in with neurologist for #migraine & #FunctionalNeurologicalDisorder went well. No changes to meds or treatment, which is positive.

Grateful.

💜🧡

Annual check in with neurologist for #migraine & #FunctionalNeurologicalDisorder went well. No changes to meds or treatment, which is positive.

Grateful.

💜🧡

Received this at @[email protected] practice Sunday.

From a reader, Bill Lauris, who wrote that he’s followed my coverage and #functionalneurologicaldisorder battle.

Thanks, Bill. And sending you wishes for healing your way.

❤️

Received this at @[email protected] practice Sunday.

From a reader, Bill Lauris, who wrote that he’s followed my coverage and #functionalneurologicaldisorder battle.

Thanks, Bill. And sending you wishes for healing your way.

❤️

By David Tuller, DrPH

In August, I submitted a letter to NeuroImage: Clinical concerning inflated rates of prevalence of functional neurological disorder, on behalf of myself and nine colleagues. After the letter went through peer review and a round of revisions, I was informed in early November that it had been accepted, as I noted in a blog post.

Our letter was a response to a 2021 article that cited a seminal 2010 study in asserting that FND was the second-most-common presentation at out-patient neurology clinics. This assertion was untrue—the 2010 article found that the number of cases qualifying as conversion disorder, as FND was then called, was way down the list of diagnoses. I had initially been informed that our letter might be published within a couple of weeks. As it turns out, the journal is planning to release it along with an expected response from the authors of the 2021 paper, which certainly makes sense. I’ve been told that the exchange is likely to be published this or next month.

(Notwithstanding my concerns about exaggerated claims made by FND investigators, it is important to make clear that patients with FND diagnoses experience tremendous suffering. A patient who goes by the moniker @FnDPortal has written a compelling and sometimes harrowing essay, Cadenza for Fractured Consciousness: A Personal History of the World’s Most Misunderstood Illness, that is well worth a read in order to understand some of the struggles that can accompany the condition.)

If the NeuroImage: Clinical article—“Neuroimaging in functional neurological disorder: state of the field and research agenda”—had been the only one to include this error, I likely wouldn’t have bothered to counter it. However, it is just one of the more than fifty papers in peer-reviewed journals that have misrepresented the FND prevalence found in the 2010 article and related studies from the same research project, the Scottish Neurological Symptoms Study. The #2 statement is often combined with the parallel claim that 16% of outpatient neurology patients received FND diagnoses. In the SNSS, headache, at 19%, was the most common presentation. However, only 209 out of 3781 study subjects, or 5.5%, received diagnoses that could be categorized as conversion disorder. Any claim that the SNSS found FND to be the second-most-common diagnosis, with a prevalence of 16%, is indisputably false.

I’ve been trying to correct the record on this matter for more than a year, with letters to investigators and journals requesting corrections. (A sharp-eyed source first alerted me to these discrepancies.) This request has been either rebuffed or ignored–so I am pleased that NeuroImage: Clinical has accepted our letter and that accurate information on this matter will soon be in the published record. In the meantime, I’ve included below the text of the preprint of the letter, which can also be accessed here. (The final version is largely the same, but with a few tweaks.)

**********

Letter to NeuroImage: Clinical

An article in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al, 2021), cited a prominent paper (Stone et al, 2010) as evidence for the assertion that functional neurological disorder (FND) is the “2nd most common outpatient neurologic diagnosis.” Although studies have yielded varying FND prevalence rates, the claim that it is the second-most common diagnosis at outpatient neurology clinics represents an erroneous interpretation of the findings of the referenced 2010 paper.

FND is the current name for what was formerly called conversion disorder, the diagnosis previously given to patients believed to have psychogenic motor and gait dysfunctions, sensory deficits, and non-epileptic seizures. According to the 2013 edition of the Diagnostic and Statistical Manual of Mental Disorders and as noted in Perez et al, FND is not a diagnosis of exclusion but requires the presence of specific “rule-in” clinical signs believed to be incompatible with known neurological disease. Some of these clinical signs have long been used by neurologists and other clinicians to help them identify cases of conversion disorder.

Stone et al’s 2010 paper was one of several arising from the Scottish Neurological Symptoms Study (SNSS). The study reviewed records from multiple outpatient neurology clinics and reported that 209 of 3781 attendees, or less than 6%, received diagnoses compatible with conversion disorder–in other words, what would now be called FND. In terms of ranking, this group of patients—labeled in the SNSS as having “functional” symptoms or diagnoses–was far down the list. The study found higher rates of many other conditions, including headache (19%), epilepsy (14%), peripheral nerve disorders (11%), miscellaneous neurological disorders (10%), multiple sclerosis/demyelination (7%), spinal disorders (6%) and Parkinson’s disease/movement disorders (6%).

Earlier this year, a paper in the European Journal of Neurology (Mason et al, 2023) cited a different SNSS paper (Stone et al, 2009) to support the assertion that FND prevalence at outpatient neurology clinics was 5.4%—far lower than the percentage needed to be the “2nd most common” diagnosis. Moreover, the authors of another paper (Foley et al, 2022) have recently issued a correction for the same misstatement of FND prevalence from the SNSS findings as the one identified in Perez et al.

The assertion that the SNSS found FND to be the “2nd most common” diagnosis at outpatient neurology clinics is based on a parallel and commonly repeated claim that the study found the prevalence in these settings to be 16% (e.g. Ludwig et al, 2018). That rate is almost three times the 5.4% prevalence recently highlighted in Mason et al. The extra patients included in this greatly expanded FND category were another 10% collectively identified inthe SNSS as having “psychological” symptoms or diagnoses. These “psychological” patients fell into a range of clinical sub-categories, among them hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, repetitive strain injury, and alcohol excess. The SNSS paper cited in Perez et al reported that a combined grouping of the patients with “functional and psychological” symptoms or diagnoses had a prevalence of 16% but did not provide any evidence that the 10% included under the “psychological” label met, or could have met, the explicit FND requirement for rule-in clinical signs.

FND is not synonymous with the broader “functional and psychological” category in the SNSS and should not be presented as if it were. The post-hoc reinterpretation of previously reported data in a way that conflates FND with other complex conditions—almost tripling its apparent prevalence in the process–is an example of the phenomenon known as diagnostic creep. In any event, the SNSS results are a matter of record. Whatever future studies might determine about FND rates, the published findings cited by Perez et al and addressed in this letter do not support either the claim that it is the “2nd most common” diagnosis in outpatient neurology clinics or the related claim that its prevalence at these venues is 16%.

Sincerely–

David Tuller (corresponding author)
Center for Global Public Health
School of Public Health
University of California, Berkeley
Berkeley, CA, USA

David Davies-Payne
Department of Radiology
Starship Children’s Hospital
Auckland, New Zealand

Jonathan Edwards
Department of Medicine
University College London
London, England, UK

Keith Geraghty
Centre for Primary Care and Health Services Research
Faculty of Biology, Medicine and Health
University of Manchester
Manchester, England, UK

Calliope Hollingue
Center for Autism and Related Disorders/Kennedy Krieger Institute
Department of Mental Health/Johns Hopkins Bloomberg School of Public Health 
Johns Hopkins University
Baltimore, MD, USA

Mady Hornig
Department of Epidemiology
Columbia University Mailman School of Public Health
New York, NY, USA

Brian Hughes
School of Psychology
University of Galway
Galway, Ireland 

Asad Khan
North West Lung Centre
Manchester University Hospitals
Manchester, England, UK

David Putrino
Department of Rehabilitation Medicine
Icahn School of Medicine at Mt Sinai
New York, NY, USA.

John Swartzberg
Division of Infectious Diseases and Vaccinology
School of Public Health
University of California, Berkeley
Berkeley, CA, USA.

References:

Foley C, Kirkby A, Eccles F, 2022. A meta-ethnographic synthesis of the experiences of stigma amongst people with functional neurological disorder. Disability and Rehabilitation. DOI:10.1080/09638288.2022.2155714.

Ludwig L, Pasman J, Nicholson T, et al, 2018. Stressful life events and maltreatment inconversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies. Lancet Psychiatry; 5:307–320.

Mason I, Renée J, Marples I, et al, 2023. Functional neurological disorder is common in patients attending chronic pain clinics. Eur J Neurol. DOI: 10.1111/ene.15892.

Perez D, Nicholson T, Asadi-Pooya A, et al, 2021. Neuroimaging in functional neurological disorder: state of the field and research agenda. Neuroimage Clin; 30:102623.

Stone J, Carson A, Duncan R, et al, 2009. Symptoms ‘unexplained by organic disease’ in 1144 new neurology out-patients: how often does the diagnosis change at follow-up? Brain; 132(10): 2878–2888.

Stone J, Carson A, Duncan R, et al, 2010. Who is referred to neurology clinics?—the diagnoses made in 3781 new patients. Clin Neurol Neurosurg; 112(9):747-751.

(Originally posted on Virology Blog.)

https://trialbyerror.org/2023/12/11/update-on-our-letter-concerning-the-prevalence-of-functional-neurological-disorder/

#2 #FND #functionalNeurologicalDisorder

By David Tuller, DrPH

As I have regularly noted, patients with diagnoses of functional neurological disorder (FND) experience tremendous suffering. A patient who goes by the moniker @FnDPortal has written a compelling and sometimes harrowing essay, Cadenza for Fractured Consciousness: A Personal History of the World’s Most Misunderstood Illness, that is well worth a read in order to understand some of the struggles that can accompany the condition.

But having empathy for FND patients does not mean giving carte blanche to experts to disseminate misinformation. For more than a decade, leaders in this domain have been citing a seminal 2010 study to argue in dozens of articles in the medical literature that FND is the second-most-common diagnosis at outpatient neurology clinics and/or that its prevalence in these settings is 16%. Within the field itself, these repeated claims seem to have attained the status of “fact”—even though they misrepresent the data. The only appropriate prevalence for the category from the 2010 study was less than 6%, which placed it way down the list of diagnoses.

I have written several posts regarding this prevalence-inflation, to which I was first alerted by a sharp-eyed colleague. Investigators and journals have rebuffed or ignored requests for corrections. But the journal NeuroImage: Clinical has now accepted a letter that highlights the issue. Besides me, the signatories are David Davies-Payne, Jonathan Edwards, Keith Geraghty, Calliope Hollingue, Mady Hornig, Brian Hughes, Asad Khan, David Putrino and John Swartzberg. (Their various affiliations are on the letter itself.)

The journal sent out our initial submission for peer review.  We revised it per the requested changes. Now the revised version has been deemed ready for publication. It should be up within weeks. Although I have disagreed with some editorial decisions, I appreciate the overall care with which the journal has handled the matter. This letter might be the first in a peer-reviewed journal to challenge these inflated prevalence claims and explain how they were constructed.

To me, this inflation of numbers from a well-known body of research just seems weird. I mean, it’s very easy to check. It doesn’t take much to compare these statements to the actual numbers reported in the 2010 study, which was part of a larger project called the Scottish Neurology Symptoms Study. The hyped-up claims are based on combining a whole bunch of participants labeled in the study as having “psychological” conditions (around 10%) with the much smaller number identified as having “functional” symptoms (less than 6%)—what we would now call FND. Conflating these categories and asserting that the entire group of 16% represented FND is unwarranted. (The largest diagnostic group was headache, at 19%.)

As we note in our letter, this sort of exaggeration contributes to the phenomenon known as diagnosis creep. FND experts might believe the higher rates (#2 prevalence, at 16%) are a better reflection of their current clinical experience. But that belief does not justify re-interpreting published data and lumping together unlike groups in a way that bolsters their questionable statistical assertions. Epidemiology graduate students at Berkeley would not get away with this sort of data manipulation. It is certainly not what would be expected from experienced investigators.

In the meantime, the final submitted version of our letter is available on a pre-print server. Here’s the top part:

An article in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al, 2021), cited a prominent paper (Stone et al, 2010) as evidence for the assertion that functional neurological disorder (FND) is the “2nd most common outpatient neurologic diagnosis.” Although studies have yielded varying FND prevalence rates, the claim that it is the second-most common diagnosis at outpatient neurology clinics represents an erroneous interpretation of the findings of the referenced 2010 paper.

FND is the current name for what was formerly called conversion disorder, the diagnosis previously given to patients believed to have psychogenic motor and gait dysfunctions, sensory deficits, and non-epileptic seizures. According to the 2013 edition of the Diagnostic and Statistical Manual of Mental Disorders and as noted in Perez et al, FND is not a diagnosis of exclusion but requires the presence of specific “rule-in” clinical signs believed to be incompatible with known neurological disease. Some of these clinical signs have long been used by neurologists and other clinicians to help them identify cases of conversion disorder.

Stone et al’s 2010 paper was one of several arising from the Scottish Neurological Symptoms Study (SNSS). The study reviewed records from multiple outpatient neurology clinics and reported that 209 of 3781 attendees, or less than 6%, received diagnoses compatible with conversion disorder–in other words, what would now be called FND. In terms of ranking, this group of patients—labeled in the SNSS as having “functional” symptoms or diagnoses–was far down the list. The study found higher rates of many other conditions, including headache (19%), epilepsy (14%), peripheral nerve disorders (11%), miscellaneous neurological disorders (10%), multiple sclerosis/demyelination (7%), spinal disorders (6%) and Parkinson’s disease/movement disorders (6%)...

You can read the rest here…

(Originally posted on Virology Blog.)

https://trialbyerror.org/2023/11/02/letter-on-inflated-fnd-prevalence-rates-accepted-for-publication/

#FND #functionalNeurologicalDisorder

"Letter to Journal about Inflated Claims of FND Prevalence"

David Tuller DrPH continues to pursue and correct a false claim over-representing the prevalence of #FunctionalNeurologicalDisorder (#FND). The authors of a paper containing this claim in the journal NeuroImage: Clinical had agreed to correct it, but then changed their mind. The journal invited Tuller et al to instead write a letter which he shares in his article

https://shorturl.at/fkyLM

"Letter to Journal about Inflated Claims of FND Prevalence"

David Tuller DrPH continues to pursue and correct a false claim over-representing the prevalence of #FunctionalNeurologicalDisorder (#FND). The authors of a paper containing this claim in the journal NeuroImage: Clinical had agreed to correct it, but then changed their mind. The journal invited Tuller et al to instead write a letter which he shares in his article

https://shorturl.at/fkyLM

"Letter to Journal about Inflated Claims of FND Prevalence"

David Tuller DrPH continues to pursue and correct a false claim over-representing the prevalence of #FunctionalNeurologicalDisorder (#FND). The authors of a paper containing this claim in the journal NeuroImage: Clinical had agreed to correct it, but then changed their mind. The journal invited Tuller et al to instead write a letter which he shares in his article

https://shorturl.at/fkyLM

"Letter to Journal about Inflated Claims of FND Prevalence"

David Tuller DrPH continues to pursue and correct a false claim over-representing the prevalence of #FunctionalNeurologicalDisorder (#FND). The authors of a paper containing this claim in the journal NeuroImage: Clinical had agreed to correct it, but then changed their mind. The journal invited Tuller et al to instead write a letter which he shares in his article

https://shorturl.at/fkyLM

By David Tuller, DrPH

I have spent some time trying to correct the record on the reported prevalence of functional neurological disorder (FND). As I have documented, leaders of the FND field have spent the last decade misrepresenting the findings of a seminal 2010 study, Stone et al, to claim that this diagnosis is the second-most-common presentation at outpatient neurology clinics, at 16%.

These twin claims about the prevalence rates found in Stone et al are categorically false—as I have pointed out over and over again. In fact, Stone et al reported that less than 6% of patients at the clinics surveyed were diagnosed with what would now be called FND, the new name for what used to be called conversion disorder; this clinical entity was therefore way down the list of diagnoses. To assert otherwise is to engage in what is clearly a form of the phenomenon known as “diagnostic creep.” There are no decent excuses for such flagrantly anti-scientific behavior as mis-citing key data from a seminal study in your field of expertise to almost triple the apparent prevalence of the condition of interest.

At least 50 papers in multiple journals have included one or both of these misstatements about the rates of FND found in Stone et al. I have sent letters to a number of journals asking for corrections. Several colleagues have co-signed these appeals. As I reported in June, one journal—NeuroImage: Clinical–agreed to correct a 2021 paper from Perez et al that had indisputably mis-cited the 2010 paper. I then began referencing that upcoming correction in letters I sent to other journals. I also sent a letter directly to the lead and senior authors of the 2021 paper, thanking them for agreeing to the correction in NeuroImage: Clinical and asking them to initiate similar corrections in other papers they co-authored. (They did not respond.)

I subsequently heard from NeuroImage: Clinical that the authors had withdrawn their agreement to the correction. Wow! I’d never heard of such a thing, and neither had my co-signatories, but there it was. The authors had acknowledged that a correction was warranted—and then, apparently, unacknowledged that self-evident reality. Perhaps they had not fully grasped that correcting this obvious error in one paper meant correcting it across the board. Who knows? No explanation for this unusual reversal was provided.

In any event, the journal invited us to submit a letter for publication instead. We have done that, and it is now in the process of being reviewed. If the letter is accepted, I assume the authors will be given a chance to respond. In the meantime, the letter has been posted on a pre-print server and is now in the public domain, so I have included it below.

**********

Inaccurate Reference Regarding FND Prevalence Requires Correction: Comment on “Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al, 2021), published in NeuroImage: Clinical

To the editor:

An article in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda” (Perez et al, 2021), cited a prominent paper (Stone et al, 2010) to assert that functional neurological disorder (FND) is the “2nd most common outpatient neurologic diagnosis.”

This assertion about the findings of the 2010 paper is unambiguously false. It requires a correction. Indeed, when we first alerted the journal about this matter, the authors agreed to publish a corrigendum—an offer they subsequently withdrew.

The 2010 paper was one of several arising from the Scottish Neurological Symptoms Study (SNSS), which reviewed records from 36 outpatient neurology clinics and reported that 209 of 3781 attendees–less than 6%–received a diagnosis of “functional” symptoms or what could also be called conversion disorder, the former name for FND. The study found higher rates of many other diagnoses, including headache (19%), epilepsy (14%), peripheral nerve disorders (11%), miscellaneous neurological disorders (10%), multiple sclerosis/demyelination (7%), spinal disorders (6%) and Parkinson’s disease/movement disorders (6%).

Earlier this year, a paper in the European Journal of Neurology (Mason et al, 2023) cited another SNSS paper (Stone et al, 2009) to note an FND prevalence at outpatient neurology clinics of 5.4%—far below the level needed to be “2nd most common.” Of note, the lead and second authors of the SNSS papers were co-authors of this 2023 article. Moreover, the authors of another study (Foley et al, 2022) have recently corrected the same misrepresentation of the SNSS findings as the one identified in Perez et al, 2021.

The “2nd most common” assertion is based on a parallel claim that the SNSS found an FND prevalence of 16% (e.g. Ludwig et al, 2018)–almost triple the 5.4% rate cited recently in Mason et al, 2023. The extra patients included in this expanded FND category were the 10% collectively identified in the SNSS as having “psychological” symptoms; they fell into a hodge-podge of diagnostic sub-categories, among them hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, repetitive strain injury, and alcohol excess. The SNSS reports included a combined “functional/psychological” grouping but did not provide evidence that the 10% with “psychological” symptoms met or could have met criteria for FND, which is not a diagnosis of exclusion but requires specific confirmatory clinical signs.

The post-hoc reinterpretation of previously reported data in a way that conflates FND with other complex conditions and almost triples its apparent prevalence is an example of the phenomenon known as diagnostic creep. But the SNSS findings are a matter of record. It should not be considered contentious to point out that these findings do not support the claim that FND is the “2nd most common” diagnosis at outpatient neurology clinics, or that the prevalence is 16%. The accurate assessment and transparent reporting of prevalence rates are core public health functions. The failure to correct self-evident errors is harmful to the scientific process and to the public’s trust in the integrity of the medical literature.

Sincerely–

David Tuller (corresponding author)
Center for Global Public Health
School of Public Health
University of California, Berkeley
Berkeley, CA, USA

David Davies-Payne
Department of Radiology
Starship Children’s Hospital
Auckland, New Zealand

Jonathan Edwards
Department of Medicine
University College London
London, England, UK

Keith Geraghty
Centre for Primary Care and Health Services Research
Faculty of Biology, Medicine and Health
University of Manchester
Manchester, England, UK

Calliope Hollingue
Center for Autism and Related Disorders/Kennedy Krieger Institute
Dept of Mental Health/Johns Hopkins Bloomberg School of Public Health 
Johns Hopkins University
Baltimore, MD, USA

Mady Hornig
Department of Epidemiology
Columbia University Mailman School of Public Health
New York, NY, USA

Brian Hughes
School of Psychology
University of Galway
Galway, Ireland

Asad Khan
North West Lung Centre
Manchester University Hospitals
Manchester, England, UK

David Putrino
Department of Rehabilitation Medicine
Icahn School of Medicine at Mt Sinai
New York, NY, USA

John Swartzberg
Division of Infectious Diseases and Vaccinology
School of Public Health
University of California, Berkeley
Berkeley, CA, USA.

References:

Foley C, Kirkby A, Eccles F, 2022. A meta-ethnographic synthesis of the experiences of stigma amongst people with functional neurological disorder. Disability and Rehabilitation. DOI: 10.1080/09638288.2022.2155714.

Ludwig L, Pasman J, Nicholson T, et al. Stressful life events and maltreatment in conversion (functional neurological) disorder: systematic review and meta-analysis of case-control studies, 2018. Lancet Psychiatry; 5:307–320.

Mason I, Renée J, Marples I, et al, 2023. Functional neurological disorder is common in patients attending chronic pain clinics. Eur J Neurol. DOI: 10.1111/ene.15892.

Perez D, Nicholson T, Asadi-Pooya A, et al, 2021. Neuroimaging in functional neurological disorder: state of the field and research agenda. Neuroimage Clin; 30:102623.

Stone J, Carson A, Duncan R, et al, 2009. Symptoms ‘unexplained by organic disease’ in 1144 new neurology out-patients: how often does the diagnosis change at follow-up? Brain; 132(10): 2878–2888.

Stone J, Carson A, Duncan R, et al, 2010. Who is referred to neurology clinics?—the diagnoses made in 3781 new patients. Clin Neurol Neurosurg; 112(9):747-751.

(Originally posted on Virology Blog.)

#correction #david-perez #fnd #functional-neurological-disorder

https://trialbyerror.org/2023/09/07/letter-to-journal-about-inflated-claims-of-fnd-prevalence/

By David Tuller, DrPH

Several colleagues and I recently wrote to the journal NeuroImage: Clinical to request a correction in a 2021 article about functional neurological disorder (FND). The article included the false claim that a seminal 2010 study found that FND was the second-most-common diagnosis at outpatient neurology clinics. In fact, FND—called conversion disorder at the time—was the eighth-most-common diagnosis, with a prevalence of 5.5%. The #2 claim was based on the notion that the prevalence was almost triple that, at 16%.

The lead and senior authors of the paper, David Perez and Selma Aybek, are experts in the field. The many co-authors included a virtual who’s who of FND investigators. The journal responded within days to let us know that the authors had agreed to a correction; the editorial team asked for our input on the proposed language. We took this quick response as a welcome acknowledgement that the argument for a correction was air-tight and indisputable. We were, however, dissatisfied with the authors’ proposal, and we offered alternate language.

Last week, we learned that the authors had not taken our advice but had nonetheless elaborated on their correction. We still believed it fell short of what was appropriate, given the substantive nature of the initial error, but accepted the new version as a done deal. I described the correction but did not publish the text because it was not ours to publish.

Unfortunately, the article in question is only one of dozens of papers by leading FND experts that have also cited Stone et al to argue that FND was the second-most-common diagnosis and/or had a prevalence at outpatient neurology clinics of 16%. To start the process of seeking corrections in these additional papers as well, I have sent a letter to Perez and Aybek. The letter notes that we found at least nine additional papers for which one of them served as lead or senior author that contained similar mis-citations of Stone et al.

Here’s the letter:

Dear Dr Perez and Professor Aybek–

On behalf of our group, I want to thank you both for agreeing to correct an erroneous statement in a 2021 article published by the journal NeuroImage: Clinical. The paper, “Neuroimaging in functional neurological disorder: state of the field and research agenda,” cited Stone et al, a 2010 study, to assert categorically that functional neurological disorder (FND) was the second-most-common diagnosis at outpatient neurology clinics.

Stone et al was one of several papers emerging from a research project called the Scottish Neurological Symptoms Study (SNSS). The assertion that FND was the #2 diagnosis was based on the parallel claim that it was identified in 16% of study participants.

As my colleagues and I noted in our letter to the journal, these twin prevalence claims regarding the SNSS are unsustainable, given the actual findings. We presume the self-evident discrepancy between the statement in the paper and the evidence from the SNSS is why the journal’s editorial team responded within days to our request for a correction. (I have cc’d the co-signatories of the letter to the journal.)

As should be clear to anyone reading Stone et al and other papers from the SNSS, the research reported a prevalence rate of less than 6% for conversion disorder, the standard name for FND at the time–not 16%. At the lower rate, it was the eighth-most-common presentation at neurology outpatient clinics, not the second-most.

It goes without saying—or at least it should–that it is inappropriate to reinterpret these data post-hoc and effectively triple the reported prevalence by lumping in many other patients with “functional” or “medically unexplained” disorders but not FND. The former are diagnoses of exclusion; in contrast, an FND diagnosis requires the presence of positive rule-in clinical signs. Combining these two sets of study participants into one larger group and then categorically asserting that they all had FND is unwarranted and unjustifiable.

Subsequent prevalence studies are irrelevant when assessing the accuracy of statements citing Stone et al or other SNSS papers. So are investigators’ personal notions about prevalence rates, no matter how sincerely held. We remain perplexed that the entire FND field seems to have been disseminating misinformation about the SNSS results for so many years.

Now that the correction for Perez et al is in process, it is critical that the dozens of other papers containing the same questionable claims also undergo scrutiny. Articles citing the exact same set of data should not be providing completely different prevalence rates; some top FND investigators have endorsed a prevalence of less than 6% in some papers and a rate of 16% in others. These conflicting accounts render this body of work epidemiologically incoherent and suggest an eagerness to hype prevalence in ways that favor investigators’ beliefs and interests.

We have identified similar mis-citations of Stone et al in at least nine other papers for which one of you was either the lead or the senior author. I have listed them below, along with the sentences requiring corrections. (It is possible we have missed some publications. In addition, the list does not include papers requiring corrections for which one or both of you were co-authors but not the lead or senior author; our group will address those separately.)

1) Aybek S , Nicholson TR, Zelaya F, O’Daly OG, Craig TJ, David AS, Kanaan RA. Neural correlates of recall of life events in conversion disorder. JAMA Psychiatry. 2014 Jan;71(1):52-60.
***Sentence requiring correction: “Conversion disorder (CD), also known as hysteria, is by no means a historical entity, accounting for 16% of neurology outpatients.”

2) Apazoglou K, Mazzola V, Wegrzyk J, Frasca Polara G, Aybek S. Biological and perceived stress in motor functional neurological disorders. Psychoneuroendocrinology. 2017 Nov;85:142-150.
***Sentence requiring correction: “FND represents the second commonest cause for a neurological consultation after headache.”

3) Frasca Polara G, Fleury V, Stone J, Barbey A, Burkhard PR, Vingerhoets F, Aybek S. Prevalence of functional (psychogenic) parkinsonism in two Swiss movement disorders clinics and review of the literature. J Neurol Sci. 2018 Apr 15;387:37-45.
***Sentence requiring correction: “Prevalence estimates of functional neurological disorders varies from 6 to 15% of patients presenting to neurological services and represent the second commonest cause for a neurology consultation after headache.”

4) Jalilianhasanpour R, Ospina JP, Williams B, Mello J, MacLean J, Ranford J, Fricchione GL, LaFrance WC Jr, Perez DL. Secure attachment and depression predict 6-month outcome in motor functional neurological disorders: a prospective pilot study. Psychosomatics. 2019 Jul-Aug;60(4):365-375.
***Sentence requiring correction: “Functional neurological disorder (FND)/conversion disorder is a common neuropsychiatric condition, estimated to be the second most common outpatient referral to neurology clinics.” 

5) Ospina JP, Jalilianhasanpour R, Perez DL. The role of the anterior and midcingulate cortex in the neurobiology of functional neurologic disorder. Handb Clin Neurol. 2019;166:267-279.
***Sentence requiring correction: “Importantly, FND is the second-most common referral to outpatient neurology.”

6) Cretton A, Brown R, LaFrance WC Jr, Aybek S. What does neuroscience tell us about the conversion model of functional neurological disorders? J Neuropsychiatry Clin Neurosci. 2020 Winter;32(1):24-32.
***Sentence requiring correction: “FND is the second most common cause of a neurological outpatient visit after headache.” 

7) Perez DL, Hunt A, Sharma N, Flaherty A, Caplan D, Schmahmann JD. Cautionary notes on diagnosing functional neurologic disorder as a neurologist-in-training. Neurol Clin Pract. 2020 Dec;10(6):484-487.
***Sentence requiring correction: “FND is among the most common conditions seen by neurologists across outpatient (2nd only to headache) inpatient, and emergency department settings.”

8) Diez I, Williams B, Kubicki MR, Makris N, Perez DL. Reduced limbic microstructural integrity in functional neurological disorder. Psychol Med. 2021 Feb; 51(3): 485-493.
***Sentence requiring correction: “For much of the 20th century, functional neurological (conversion) disorder (FND) was marginalized across neurology and psychiatry despite being the second most common reason for neurological referral and incurring significant healthcare costs.”

9) Paredes-Echeverri S, Maggio J, Begue I, Pick S, Nicholson TR, Perez DL. Autonomic, endocrine, and inflammation profiles in functional neurological disorder: a systematic review and meta-analysis. J Neuropsychiatry Clin Neurosci. 2022 Winter;34(1):30-43.
***Sentence requiring correction: “FND is the second most common condition seen in outpatient neurology clinics, a finding compounded by observations of high health care costs and poor prognoses among many patients.” 

As a courtesy, I wanted to alert both of you that our group intends to continue our efforts by contacting these journals, noting the acknowledgement of error in the NeuroImage: Clinical paper, and requesting corrections. It would be helpful if you could let us know whether you yourselves have already informed these journals of the need for corrections, or have any plans to do so. Such steps on your part would obviously facilitate and speed up the process of ensuring that the medical literature on FND adheres to the facts.

Thanks again for acknowledging the error in the NeuroImage: Clinical paper.

Best–David

David Tuller, DrPH
Senior Fellow in Public Health and Journalism
Center for Global Public Health
School of Public Health
University of California, Berkeley

(Originally posted on Virology Blog.)

#2 #david-perez #fnd #functional-neurological-disorder

https://trialbyerror.org/2023/06/30/a-letter-requesting-corrections-of-inflated-prevalence-rates-in-nine-more-fnd-papers/

By David Tuller, DrPH

For years, experts in functional neurological disorder (FND) have cited a seminal study in their field to claim that the diagnosis was the second-most-common presentation at outpatient neurology clinics, with a prevalence of 16%. This claim was, and is, categorically untrue. The Scottish Neurological Symptoms Study (SNSS), which yielded multiple papers about a dozen years ago, actually found that 209 out of 3781, or 5.5%, were identified as having conversion symptoms. (Conversion disorder is the old name for FND.) At that rate, it was the eighth-most-common presentation in the SNSS, not #2.

This discrepancy was pointed out to me a year or so ago by a valued source. I blogged and posted on social media about the issue. I also wrote—twice–to a major journal seeking a correction in one such paper. I received no response. Two weeks ago, I sent a letter seeking a correction to another major journal, NeuroImage: Clinical. Several colleagues—from Berkeley, Columbia, Johns Hopkins, University College London, etc—co-signed the letter.

The authors have now agreed to correct the false statement that the SNSS found FND to be the second-most-common presentation. The correction is inadequate in some respects. Nevertheless, I hope it means that they will at least no longer cite the SNSS to claim FND is the #2 presentation at outpatient neurology clinics, with a prevalence of 16%. I also hope the FND experts themselves will now initiate corrections in the dozens of papers that have included these untrue data points. It will be a tedious process for all involved if our group has to send out letters to journal editors about every single one of these papers.

I need to say I was impressed with the speed with which the journal handled our request. Within five days of sending our initial letter, I heard back from an editor, Anna Bankhoff, who was seeking our group’s input about proposed language for a correction. I attributed this quick action to the integrity of the journal; the authors themselves have previously exhibited little interest in responding to these concerns and cleaning up the mess. The authors presumably understood that a correction in one paper meant it would be hard to object to requests for corrections in every other paper with the same misinformation.

This was the sentence in question: ““This renewed interest [in FND] parallels recognition that FND is the 2nd most common outpatient neurologic diagnosis, with many patients remaining chronically symptomatic and incurring high healthcare costs.” The reference was to Stone et al, a 2010 paper arising from the SNSS.

The initial proposal from the authors was to remove the #2 claim and simply say that FND was a “common” presentation. We responded, as a group, that we found that solution inadequate. Here’s what we wrote:

Dear Dr Bonkhoff–

I have consulted with my colleagues, and first we would like to thank the journal and the authors for promptly acknowledging that Perez et al includes an error requiring a corrigendum. I think it’s fair to say that this sort of swift action does not happen frequently in academic publishing, so it is very much appreciated.

As regards the proposed wording, we believe it is definitely a step in the right direction but not in itself sufficient. The original sentence compared FND to other diagnoses by calling it the second-most-common presentation while inaccurately citing findings from the Scottish Neurological Symptoms Study (SNSS). To undo the misimpression generated by this claim, the replacement sentence should also place FND in the context of other diagnoses.

From our perspective, calling it “common” and leaving it at that is not enough. First, the understanding of “common” is dependent upon the circumstances. Readers of the article could easily assume “common” means 20% or 30% or 40% of patients–not 5.5%. Second, the proposed phrasing doesn’t indicate that FND was not, after all, the #2 diagnosis in the SNSS but down the list at #8—after headache, epilepsy, peripheral nerve disorders, miscellaneous neurological disorders, multiple sclerosis/demyelination, spinal disorders, and Parkinson’s disease/movement disorders. Therefore, referring to FND as “common” would not fully address the problem created by the original misstatement in the first place.

(As a side note, the phrase “outpatient neurologic diagnosis” is ambiguous and could easily be misinterpreted to mean that these diagnoses were made in primary care and not in secondary care settings–i.e. neurology clinics.)

Another consideration: Two of the co-authors of Perez et al, Professors Alan Carson and Jon Stone, are also co-authors of a new paper called “Functional neurological disorder is common in patients attending chronic pain clinics,” published on May 23rd in the European Journal of Neurology. Citing the SNSS findings, this article reported that “the prevalence of typical FND in patients attending neurology outpatient clinics is 5.4%.” (Since this “typical FND” group included 209 out of 3781 patients, as we noted in our original communication with you, it is unclear why the figure given is 5.4% and not 5.5%.) 

Given this most recent definitive statement about the SNSS, it seems reasonable to suggest that Perez et al make a similarly clear account of the prevalence of “typical” FND. We recommend one of the following options to replace the original sentence:

“This renewed interest parallels recognition that FND is a relatively common diagnosis in neurology outpatient clinics, being found in 5.5% of referrals, with many patients remaining chronically symptomatic and incurring high healthcare costs.” (Or 5.4%, if our calculation is somehow wrong.)

“This renewed interest parallels recognition that FND is a relatively common diagnosis in neurology outpatient clinics, being found almost as often as multiple sclerosis and Parkinson’s, with many patients remaining chronically symptomatic and incurring high healthcare costs.”

Thank you again for the opportunity to comment on this proposed correction involving the erroneous citation in Perez et al. We look forward to the resolution of this matter. 

Best–David

David Tuller, DrPH
Senior Fellow in Public Health and Journalism
Center for Global Public Health
School of Public Health
University of California, Berkeley

**********

The journal responds, and we respond again

That letter was sent last Monday. This morning, I received a response from the editor-in-chief, Dr Andrew Zalesky, that the authors had revised the correction and that it would be published as soon as possible. As in the previous proposal, the correction includes the statement that FND is “common” but then, in an additional paragraph, notes that ranking diagnoses in order is challenging because different studies yield different rates, depending on quality and methodology. The correction then cites some other research to bolster their claim that FND is “common.” (More on that additional research in a later post.) To me, the authors seem to be trying to absolve themselves of responsibility for making a bogus claim by suggesting that the entire effort to assess prevalence is fraught with issues. That might be true–but this response raises the obvious question of why these experts have spent the last decade making declarative assertions that FND is the #2 diagnosis.

Below is the response I sent to Dr Zalesky:

Dear Dr Zalesky–

Thank you for the response. We very much appreciate the speed with which you and Dr Bonkhoff have addressed this matter. 

The decision by top investigators to repeatedly disseminate untrue information about a seminal study in their field of expertise has led to significant confusion about the actual prevalence rates of FND–not least, undoubtedly, among clinicians who end up seeing and treating some of these patients. We continue to believe that the word “common” on its own is liable to be misunderstood. We also continue to believe that the most appropriate method of correcting this error would be to provide the actual information from the study whose findings were misrepresented. Nonetheless, we appreciate that the authors have acknowledged their error and we accept that the process has now reached its conclusion.  

As suggested by the persistent claim that the Scottish Neurological Symptoms Study (SNSS) found FND to be the #2 presentation at neurology clinics, leading experts at times seem to perceive FND even in the absence of the positive clinical signs that are now required for a diagnosis–or at least they are willing to include such patients in their reported prevalence rates. The phenomenon of interpreting (or misinterpreting) data to maximize apparent prevalence rates of illness has a name in public health and epidemiology. It is called “diagnosis creep.” 

To put this correction in perspective, it is also worth noting another recent reference—an accurate one–to the prevalence of FND found in the SNSS. Professor Jon Stone, a co-author of Perez et al, is also the lead author of Stone et al, the 2010 study from the SNSS cited in Perez et al. In addition, Professor Stone is one of two co-authors of the section about “conversion disorder” on the medical education site UpToDate. (Conversion disorder is the former name for what is now called FND. It is unclear why UpToDate is still using this outdated term.) A note at the bottom of this section indicates it was updated in June of 2022. 

In the epidemiology sub-section, the article states that “the point prevalence of conversion symptoms in clinical settings ranges from 2 to 6 percent.” The section cites three studies, including Stone et al. Here’s what it notes about the latter: “A prospective study of 3781 neurology outpatients found that conversion disorder was present in 6 percent.” This statement is obviously inconsistent with any claim that the study found FND to be the second-most-common presentation, which itself is based on the assertion that the prevalence was 16%.

It remains perplexing that experts in this field, including co-authors of the SNSS, have had no hesitation in tripling that study’s reported prevalence rate by lumping in many other participants who might have had “functional” disorders but did not meet the specific diagnostic criteria for FND—as if the criteria were optional or irrelevant. They clearly know that the SNSS did not in fact find FND to be the #2 diagnosis, as evidenced by the various correct citations of the data. Yet this false claim now peppers the medical literature. 

We hope FND experts take this correction to heart and exercise more caution in citing the SNSS in future papers. The many co-authors of Perez et al, a virtual who’s who of leaders in the field, might also consider initiating similar corrections in every article of theirs that includes the same mis-citation. 

Thank you again. Now that this issue is settled, I plan to blog about it. (I posted the original letter we sent but have refrained from further public comment while the question was being debated.) I will forward the link to any posts that I write.

Best–David

David Tuller, DrPH
Senior Fellow in Public Health and Journalism
Center for Global Public Health
School of Public Health
University of California, Berkeley

**********

Some further thoughts on this matter…

As noted in my response to Dr Zalesky, we still believe the use of “common” on its own is problematic—it could mean anything to anyone. The authors clearly do not want to be held to the 5.5% figure from the SNSS, even though that is the largest and most authoritative study on the issue. Instead, they prefer to leave the meaning of “common” vague, allowing readers to interpret that how they will. Presumably they believe that the higher rates are more accurate than 5.5%; I assume that’s why they have made this claim repeatedly. But even if that is their belief, it does not warrant the distortion of findings from the SNSS.

It takes an impressive amount of chutzbah to routinely mis-cite data in this way; it is hard to imagine that Berkeley graduate students in my department would get away with such misrepresentation in their dissertations without serious repercussions. It is also perplexing that the entire field of FND has accepted these mis-citations without apparent question. For top medical journals to have published dozens of papers in the last decade with these indisputably untrue claims represents a failure of the peer review process. I hope this situation triggers some soul-searching on the part of authors, peer-reviewers and journal editors about the proper way to cite study findings—although I won’t hold my breath on that score.

(Originally posted on Virology Blog.)

#2 #correction #fnd #functional-neurological-disorder #jon-stone

https://trialbyerror.org/2023/06/24/fnd-experts-agree-to-correct-inflated-prevalence-claim/

By David Tuller, DrPH

I have posted previously about how papers on functional neurological disorder (FND) have routinely mis-cited a seminal 2010 study in asserting that the diagnosis is the second-most-common presentation at neurology clinics, with a rate of 16%. In fact, the 2010 study found that only 5.5% had FND, the new name for the antiquated Freudian construct of conversion disorder. Many others apparently had symptoms that the neurologists could not explain, but that doesn’t automatically translate to a diagnosis of FND, which requires positive rule-in signs from clinical examinations.

Nonetheless, this claim—that Stone et al found FND to be the second-most-common diagnosis at neurology clinics—has gained credibility through repetition in the medical literature. But repetition doesn’t make it true.

This morning, I sent a letter to the editor of the journal NeuroImage: Clinical, asking for a correction in a 2021 paper claiming that FND is the “2nd most common” presentation at neurology clinics. Several colleagues co-signed the letter.

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Dear Professor Zalesky–

For years, leading neurologists have noted that functional neurological disorder (FND), the new term for what was formerly called conversion disorder, is not a diagnosis of exclusion but a rule-in diagnosis requiring positive signs found during clinical examination. This approach was enshrined in the fifth iteration of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), which was published in 2013. Nonetheless, FND experts appear to be overlooking this definition when making claims about rates of the diagnosis at neurology clinics.

For example, a 2021 article from Perez et al in NeuroImage: Clinical, “Neuroimaging in functional neurological disorder: state of the field and research agenda,” highlights the rule-in requirement and then asserts that FND “is the 2nd most common outpatient neurologic diagnosis” (1). The reference for this assertion is a seminal and widely cited paper from Stone et al called “Who is referred to neurology clinics?—the diagnoses made in 3781 new patients,” which was published in 2010 in Clinical Neurology and Neurosurgery” (2). 

Yet Stone et al, one of several papers arising from a research project called the Scottish Neurological Symptoms Study (SNSS), does not support the claim. According to the study, the second-most-common category of presentations at neurology clinics, after headache, was a grouping called “functional and psychological symptoms,” at 16%. An examination of this heterogeneous grab-bag of conditions indicates that it does not easily equate to what is called FND, per the DSM-5 criteria.

In the SNSS, 209 of the 3781 patients, or 5.5%, were diagnosed with “functional” symptoms such as sensory or motor disorders or non-epileptic seizures. These were identified in a related 2009 paper as cases of “conversion” symptoms (3); they would now be indisputably classified as FND. At the 5.5% rate, FND would be way down on the list of diagnoses mentioned in Stone et al, after headache (19%), epilepsy (14%), peripheral nerve disorders (11%), miscellaneous neurological disorders (10%), multiple sclerosis/demyelination (7%), spinal disorders (6%) and Parkinson’s disease/movement disorders (6%).

The other 10% of the 16% in Stone et al’s second-most-common grouping, who were defined collectively as having “psychological” symptoms, fell into a hodge-podge of sub-groups, including hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, repetitive strain injury, and alcohol excess, among others. Also lumped in with this “psychological” cohort were cases identified as “non-organic” and “no diagnosis.” Stone et al presented no evidence that any of these patients met or could have met the rule-in criteria for a more strictly defined FND diagnosis. Arguments that members of this 10% also had FND are grounded in speculation and assumption, not fact.

In subsequent articles, two of the co-authors of Stone et al endorsed the much lower rate for the specific clinical entity known as FND. In 2016, Professor Alan Carson, the second author of Stone et al, wrote the following with a co-author in the abstract of an account of the epidemiology of FND, published as a chapter of the Handbook of Clinical Neurology (4):

“The recent changes in DSM-5 to a definition based on positive identification of physical symptoms which are incongruent and inconsistent with neurologic disease and the lack of need for any psychopathology represent a significant step forward in clarifying the disorder. On this basis, FND account for approximately 6% of neurology outpatient contacts.” The text of the chapter mentioned the SNSS data and gave the exact rate for “typical FND cases” as 5.4%. (It is not clear why the figure was not 5.5%.)

In 2018, several FND experts, including Professor Carson and Professor Jon Stone, the lead author of Stone et al, published a paper in JAMA Neurology called “Current concepts in ciagnosis and treatment of functional neurological disorders” (5). Referencing the SNSS, the paper included the following statement: “In a well-designed consecutive series of 3781 outpatients of neurology clinics, 5.4% had a primary diagnosis of FND.” (Again, it is not clear why this figure was not 5.5%.) The 2018 paper noted that a larger group of patients in Stone et al had “symptoms that were described as only somewhat or not at all explained by disease.”

While these other unexplained symptoms or ailments might be called “functional” disorders in the current lexicon, they cannot reasonably be said to be equivalent to a diagnosis of FND, given the DSM-5 requirement for rule-in clinical signs. Otherwise, the 2016 and 2018 papers would have included these functional disorders as part of the FND total from Stone et al and reported that the rate was 16%, not “approximately 6%” or 5.4%.

The data have not changed since these 2016 and 2018 papers were published. Why is Stone et al now being framed, in Perez et al as well as other publications, as evidence that FND, as defined in DSM-5, is the second-most-common presentation at neurology clinics?

The popular site neurosymptoms.org, maintained by Professor Stone, sheds some light on how a claim of “second commonest reason to see a neurologist,” at a rate of 16%, could be derived from the data in Stone et al. According to the site:

“In [an] older study of 3781 new appointments across Scotland, there were 209 patients who had clear FND and another 200 who had additional functional disorder diagnoses including dizziness and cognitive symptoms which could also be included now within FND. Other patients presented with diagnoses like migraine, but the neurologists thought the main issue was an associated functional disorder. So, anything from 6-16% of patients could be said to have a functional disorder depending on how that was defined. The upper limit of that estimate would make it the second commonest reason to see a neurologist.”

First, this passage confirms the relevant point. Only 209 patients out of 3781, or 5.5%, had “clear FND”–way below the level that would be required for this diagnosis to be the second-most common. Second, the 16% figure represents merely the “upper limit” of a broad possible range of estimated rates—and not rates for “clear FND” but for the fuzzier and more expansive construct of “functional disorder depending on how that was defined.”

It is not appropriate to retroactively re-interpret the data from Stone et al and effectively triple the reported rate of “clear FND” from 5.5% to 16%–thus vaulting this diagnosis into second place on the list. FND experts presumably believe the higher number is a better reflection of current diagnostic rates. Neurosymptoms.org notes, for example, that Stone et al’s recruitment of patients occurred two decades ago and that “recognition of FND has improved” since then. But this argument, even if valid, does not justify the decision to inflate Stone et al’s reported FND rate beyond what the data showed.  

Professor Stone made a salient observation during a 2021 podcast produced by the Encephalitis Society: “Some people think that FND is a condition you diagnose when someone has neurological symptoms but you can’t find a brain disease to go along with it. And that’s absolutely not the case. Some people [i.e. clinicians] do that, but if they’re doing it like that then they’re doing it wrong.”

If clinicians who regard FND as a diagnosis of exclusion and ignore the need for rule-in signs are “doing it wrong,” per Professor Stone, then surely those who cite Stone et al to assert that FND is the second-most-common reason to see a neurologist, with a 16% rate, are also “doing it wrong.” It is confusing, not to mention epidemiologically incoherent, when FND experts report divergent rates in different papers while citing the exact same set of data.

This is especially so when the lead and second authors of Stone et al have previously made statements about the study’s rate of “typical FND” that do not support the greater claims disseminated in more recent publications, such as Perez et al. Unless the changes in the DSM-5 and the requirement for positive rule-in clinical signs are meaningless, the statement that Stone et al found FND to be the second-most-common diagnosis is categorically untrue. The citation in Perez et al—or rather, mis-citation–should be corrected.

Thank you for your attention to this matter. (The paper’s corresponding and senior authors have been cc’d on this letter, as have the co-signatories of the letter and one of the journal’s associate editors.)

Sincerely,

David Davies-Payne
Department of Radiology
Starship Children’s Hospital
Auckland, New Zealand

Jonathan Edwards
Department of Medicine
University College London
London, England, UK

Keith Geraghty
Centre for Primary Care and Health Services Research
Faculty of Biology, Medicine and Health
University of Manchester
Manchester, England, UK

Calliope Hollingue
Center for Autism and Related Disorders/Kennedy Krieger Institute
Dept of Mental Health/Johns Hopkins Bloomberg School of Public Health 
Johns Hopkins University
Baltimore, MD, USA

Mady Hornig
Department of Epidemiology
Columbia University Mailman School of Public Health
New York, NY, USA

Brian Hughes
School of Psychology
University of Galway
Galway, Ireland

Asad Khan
North West Lung Centre
Manchester University Hospitals
Manchester, England, UK

David Putrino
Department of Rehabilitation Medicine
Icahn School of Medicine at Mt Sinai
New York, NY, USA.

John Swartzberg
Division of Infectious Diseases and Vaccinology
School of Public Health
University of California, Berkeley
Berkeley, CA, USA.

David Tuller (corresponding author)
Center for Global Public Health
School of Public Health
University of California, Berkeley
Berkeley, CA, USA

*****

1. Perez D, Nicholson T, Asadi-Pooya A, et al. Neuroimaging in functional neurological disorder: state of the field and research agenda. NeuroImage: Clinical 2021; 30: 102623.

2. Stone J, Carson A, Duncan R, et al. Who is referred to neurology clinics?—The diagnoses made in 3781 new patients. Clinical Neurology and Neurosurgery 2010; 112: 747–751.

3. Stone J, Carson A, Duncan R, et al. Symptoms ‘unexplained by organic disease’ in 1144 new neurology out-patients: how often does the diagnosis change at follow-up? Brain 2009; 132: 2878-88.

4. Carson A, Lehn A. Epidemiology. Handbook of Clinical Neurology 2016; 139: 47–60.

5. Espay A, Aybek S, Carson A, et al. Current concepts in diagnosis and treatment of functional neurological disorder. JAMA Neurology 2018; 75(9): 1132–1141.

(Originally posted on Virology Blog.)

#fnd #functional-neurological-disorder

https://trialbyerror.org/2023/06/05/a-letter-regarding-inflated-prevalence-rates-for-functional-neurological-disorder/

By David Tuller, DrPH
(This is a long-ish post. Sorry! It covers two complicated issues. I want to thank an intrepid source for help with this.)

I have great sympathy for patients diagnosed with functional neurological disorder (FND). Their symptoms can be seriously disabling and their plight has long been neglected and dismissed by the medical establishment. When I post about FND, I like to recommend this well-written essay by a patient who goes by the moniker FNDPortal. The article provides a harrowing portrait of the experience of living with FND as well as a cogent account of the history of the construct.

I have, however, raised issues with how FND experts and investigators have made claims that do not seem to conform to the evidence cited. That includes the routine and unwarranted tripling of the reported FND prevalence rate from a 2010 study from Stone et al called “Who is referred to neurology clinics?—the diagnoses made in 3781 new patients,” published in the journal Clinical Neurology and Neurosurgery. FND, formerly called conversion disorder, was redefined in 2013 in the fifth edition of the Diagnostic and Statistical Manual (DSM-5), often referred to as the “psychiatric bible.” Among the changes in the new definition of the diagnosis was that it required the presence of a clinical sign incompatible with neurological disease.

As I’ve blogged here, here and here, Stone et al has repeatedly been referenced for the claim that FND–as re-defined in DSM-5–is the second-most common reason, after headache, for patients to see a neurologist, and/or that it has a 16% prevalence among new presentations at neurology clinics. That is simply not what the paper reported, as should be apparent to anyone reading it.

In fact, a 2016 chapter for the Handbook of Clinical Neurology–co-written by a co-author of Stone et al–cited a much lower number for FND prevalence: “The recent changes in the DSM-5 to a definition [of FND] based on positive identification of physical symptoms which are incongruent and inconsistent with neurologic disease and the lack of need for any associated psychopathology represent a significant step forward in clarifying the disorder. On this basis, FND account for approximately 6% of neurology outpatient contacts.” The chapter specifically mentioned the evidence from Stone et al and also provided a lower and more precise figure of FND prevalence: 5.4%. At that rate, FND would be much further down than #2 on Stone et al’s list of diagnoses, after conditions like epilepsy, peripheral nerve disorders, miscellaneous neurological disorders demyelination, spinal disorders and Parkinson’s disease/movement disorders.

The site neurosymptoms.org, which is maintained by the lead author of Stone et al, makes the same point about the study data. Of the 3781 patients, the site explains, 209 of them “had clear FND.” That’s 5.5%–basically in line with the two data points, 5.4% and “approximately 6%,” from the 2016 article. (The correct percentage using the Stone et al numbers is 5.5%. The 5.4% cited in the 2016 article appears to have been either a typo or miscalculation.)

The diagnoses given for the symptoms of these 209 patients with “clear FND” fell into the three categories most closely identified with conversion disorder, the prior name for the condition—“non-epileptic attacks,” “functional sensory,” and “functional motor.” So who were the additional 10% among the total sample of 3781 that raised the purported FND prevalence to 16%, per more recent publications? These were patients given a grab-bag of what the study identified as “psychological” diagnoses, including hyperventilation, anxiety and depression, atypical facial/temporomandibular joint pain, post-head injury symptoms, fibromyalgia, and alcohol excess, among others. Also lumped into this “psychological” group were cases assigned to categories identified as “non-organic” and “no diagnosis.”

Presumably some or many of these patients with “psychological” diagnoses might today be given some form of “functional” diagnosis, indicating that they have unexplained symptoms. Nonetheless, Stone et al offer no evidence that these additional 10% would have met DSM-5 criteria for the specific clinical entity known as FND or that they could have been ruled in as having FND through the required positive clinical signs. Perhaps some of them would have met this diagnostic burden during a current neurological exam, given advances in the field. But since FND is no longer considered a diagnosis of exclusion but one based on positive rule-in signs, the 16% prevalence claim is speculation relying on unproven assumptions–no matter how many times it is repeated as if it were a documented fact.

In a way, Stone et al set this stage for this mis-communication. In reporting the data, Stone et al combined the “approximately 6%” meeting the DSM-5 criteria for FND with the 10% given “psychological” diagnoses to create a larger category with 16% prevalence that was called “psychological/functional.” The authors did not explain exactly why they combined the two groups rather than keeping them separate. However, the decision to do so conveniently let them call this new, bigger, wildly heterogeneous category the second-most common reason to consult a neurologist, after headache at 19%. Presumably there are benefits in being able to make the argument that a category of interest is #2 rather than much lower down the line.

Unfortunately, multiple papers in recent years have confused the matter further by dropping any mention of the “psychological” group altogether and re-branding the entire 16% as having FND and/or asserting that FND is the #2 presentation. FND experts have done something similar in lectures and other public presentations. Of course, neither statement–that the FND prevalence is 16% and that it is the #2 presentation–is in accord with the 2016 chapter co-written by one of the co-authors of Stone et al; that chapter stated unequivocally that “approximately 6%” met the new DSM-5 definition of FND. Nor is the assertion of 16% prevalence in accord with the information currently provided on, neurosymptoms.org, which notes only 209 out of 3781 patients–that is, 5.5%—had “clear FND.” Hm.

Neurosymptoms.org attempts to address these inconsistencies with some serious post-hoc re-interpretation and theorizing. Besides those with “clear FND” In Stone et al, notes Neurosymptoms.org, “another 200…had additional functional disorder diagnoses including dizziness and cognitive symptoms which could also be included now within FND” and also “other patients presented with diagnoses like migraine, but the neurologists thought the main issue was an associated functional disorder.” Therefore, neurosymptoms.org concludes, “anything from 6-16% of patients could be said to have a functional disorder depending on how that was defined. The upper limit of that estimate would make it the second commonest reason to see a neurologist.”

This lengthy explanation confirms the hey point. The recent papers do not make a vague and belabored argument about the “upper limit” of a broad possible range of prevalence rates for any sort of “functional disorder depending on how it was defined.” Their claim is much more precise, specific, unambiguous, and authoritative: a categorical declaration that Stone et al found 16% to have “clear FND” –that is, diagnoses that could be called FND per the criteria outlined in DSM-5.

With this sleight-of-percentage, the wave of articles mis-citing Stone et al has in effect tripled the reported prevalence of FND as defined in DSM-5. Given that the diagnosis now requires rule-in signs and no longer requires prior trauma, the only acceptable and appropriate prevalence for FND to cite from Stone et al is 5.5% (or “approximately 6%”)—without lumping in the 10% from the “psychological” camp based on subsequent re-framing of the data.

Although published 13 years ago, Stone et al remains the largest investigation of its kind. Perhaps prevalence rates in neurology clinics based on current understandings and awareness differ from those reported in Stone et al, as neurosymptoms.org suggests. Perhaps the rates found in much, much smaller and less authoritative studies differ as well. But this much is indisputable about Stone et al itself: The findings do not support the claim that FND as defined in DSM-5 is the #2 presentation at neurology clinics with a prevalence of 16%. Clarity and consistency in reporting prevalence rates is essential to the practice of public health. For this reason and others, papers that have made this untrue assertion while citing Stone et al should be corrected.

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On another matter…Does the research really show that Hoover’s sign is close to 100% specific?

Earlier this month I posted an interview with David Putrino, a neuroscientist and physical therapist at Mt Sinai Health System in New York, about long Covid and its relationship to functional neurological disorder, or FND. My tweet of the interview drew a response from David Perez, a neurologist and psychiatrist at Boston’s Massachusetts General Hospital and a leader in the FND field. 

Dr Perez tweeted to Dr Putrino: “as a fellow clinician & researcher – I’m concerned that you are mischaracterizing Functional Neurological Disorder. While sensorimotor & cognitive domains of impairment are found in many conditions – there are positive NEUROLOGIC EXAM SIGNS that rule-in #FND.”  

In a second tweet he included six links under the slug “articles for your consideration.” These articles provided advice and guidance on diagnosing FND using the kinds of “rule-in” NEUROLOGIC EXAM SIGNS mentioned by Dr Perez. FND is the new-ish name for what has for a century or so been called conversion disorder. Since 2013, the fifth edition of the Diagnostic and Statistical Manual [DSM-5], the so-called “psychiatric bible,” has required not just the absence of known neurological disease but also the presence of clinical signs that are incompatible with such disease. (For consistency, in this post I will generally use the term FND even when writing about research that used more archaic terms like conversion disorder.) 

But the requirement in the revised definition of FND for positive clinical signs has focused awareness on a major gap in the literature. Neurologists have for decades relied on some of these time-honored procedures in diagnosing patients; however, not much if any effort was made to investigate their accuracy. 

This issue remains a challenge for the field. As Dr Perez and colleagues pointed out in “Decade of progress in motor functional neurological disorder: continuing the momentum,” a 2021 article in the Journal of Neurology, Neurosurgery and Psychiatry: “There is a need to further test the specificity, sensitivities and inter-rater reliability of the growing range of positive functional signs compared to other neurological populations, particularly given that statistical properties for some signs have been only tested in a single cohort.” 

In fact, almost all of the signs identified to test motor FND have been tested in only a single cohort, according to an article from Dr Perez and a colleague called “Diagnosis and management of functional neurological disorder,” published the following year in The BMJ. In a table of 41 “validated positive motor signs” of the kind required to rule in the motor FND diagnoses discussed in the 2021 article, 34–or 83%–were shown as tested in only a single cohort. Five were tested in two studies, and only two signs were tested in more than two.

The quintessential and most well-known example of these clinical signs—the poster-sign, if you will—is Hoover’s sign, one of the two motor FND signs found to have been tested in more than two studies. It was first recommended more than a century ago as a means of distinguishing between cases of leg weakness or paralysis caused by neurological disease and those thought to be due to “malingering” or what might then have been called hysteria but would now be called FND. (This post is already long and explaining more about Hoover’s sign and how it’s done would take space. Here’s a video about it.) 

Just like a positive Hoover’s sign serves as a rule-in indicator for functional leg weakness, the other clinical signs are used to rule in other types of FND. Articles in the FND literature about the use of these clinical signs advise that they should be viewed with some caution, that none are perfect, and that they need to be interpreted alongside the other medical information available.

When it comes to Hoover’s sign, FND experts themselves report that some other conditions, like apraxia, can generate false positives. At the same time, the FND literature frames Hoover’s sign as the exemplar of the genre and touts its “diagnostic specificity”—meaning that a positive result is always or almost always accurate. As Dr Perez and colleagues wrote in their 2021 paper: “Establishing the diagnosis of mFND [motor FND] has been made more practicable, as physical examination findings with diagnostic specificity have been identified (e.g., Hoover’s sign with an estimated specificity of 95.7-99.9%).”

(Specificity and sensitivity are complicated. In brief, the first is a measure of whether a true positive case is correctly identified by a positive test and the second is a measure of whether a true negative case is correctly identified by a negative test. There is often a trade-off between the two, but the best tests are those that measure close to 100% on both. I realize this mini-explanation will leave many a bit perplexed. Sorry!!)”

If Hoover’s sign has high diagnostic specificity for functional leg weakness, the corollary is that other conditions would rarely generate a positive result—or never, if the specificity were 100%. But if clinicians are relying on a claim of specificity that is inflated or exaggerated, other diagnoses that might explain a positive Hoover’s sign could potentially be overlooked and missed.

These implications raise a key question: Is the research into the diagnostic reliability of Hoover’s sign robust? As it turns out, the answer is—not really, despite the sign’s venerable history. The evidence base is very thin—as I explain below. Two issues are immediately apparent. First, the few studies that have been done only included handfuls of FND patients; the most authoritative validation study of Hoover’s sign had eight FND patients. Beyond that, studies were designed in a circular fashion, with Hoover’s sign apparently serving in many or all cases as a diagnostic tool initially as well as being the object of epidemiological investigation.

My colleague John Swartzberg, a public health expert and an emeritus professor of infectious diseases at University of California, Berkeley, said Hoover’s sign could be helpful in the context of other medical tests and data. But he added that the deficiencies of the studies made it hard to draw any solid conclusions from them.

“The studies looking at the sensitivity and specificity of Hoover’s sign suffer from confirmation bias and small sample size. The sign was described over 100 years ago when there was a very different understanding of neurological disease. The idea is that there is a neurological loop for the hip flexors. If there is neurological disease on one side, that loop should be interrupted. That makes some degree of sense but it does not address other possibilities, such as neuropathies.”

Dr Putrino, whose interview with me prompted Dr Perez’ tweets, said this:

“A positive Hoover’s sign basically shows us that, for whatever reason, someone is unable to initiate a voluntary muscle contraction but that they have intact spinal reflexes. There are so many things that can go wrong with the nervous system to cause this that are easily missed during a mainstream neurological exam, especially if you have a bias towards diagnosing ‘conversion disorder.’ So to immediately and over-confidently assume that a positive Hoover’s sign means ‘functional neurological disorder’ is emblematic of the sort of thinking that we would associate with a clinician who is light on anatomical knowledge.”

Jonathan Edwards, an emeritus professor of medicine at University College London, agreed that Hoover’s sign could play a role in patient assessment but that it was unwarranted to suggest it had such high specificity:

“There is no doubt that there are people with neurological symptoms that have to be assigned to unexplained central problems. There is also no doubt that in some cases the defect seems to relate more to conscious conceptions than any neuroanatomy. Sometimes signs like Hoover’s sign are quite remarkably salient. From my perspective here the problem is not with the idea that neurological symptoms can occur as a result of conscious or unconscious mental processes. The problem is the claim that anyone understands what is going on or that any such mysterious goings on can be reliably recognised with such signs.”

(I responded to Dr Perez’s tweet to Dr Putrino, since I was also on the twitter thread. In my response, I indicated that the research on Hoover’s sign seemed underwhelming and asked if he could provide data from more studies. Dr Perez did not respond. Before posting this blog, I sent him an e-mail requesting comment and promising to post his response in full if/when I receive it. In the e-mail, I also mentioned that I was writing about the FND field’s habit of mis-citing Stone et al’s 2010 paper and tripling the reported FND prevalence rates; I suggested he might respond to that concern as well.)

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Studies of Hoover’s sign: tiny samples and self-fulfilling prophecies

One study among the six links tweeted by Dr Perez was a 2014 article from Daum et al called “The value of ‘positive’ clinical signs for weakness, sensory and gait disorders in conversion disorder: a systematic and narrative review,” published in the Journal of Neurology, Neurosurgery, and Psychiatry. It was the only one of the six articles to offer an in-depth analysis of the accuracy of some of the signs, including Hoover’s sign. (A few years ago I wrote a post about this paper. This new post recycles a few paragraphs from the earlier one. I guess that would be self-plagiarism???) 

Daum et al’s 2014 review mentioned the DSM’s diagnostic change (at the time the paper was written, the change was proposed but had not yet been adopted), noting that the new definition depended on “the exclusion of neurological signs pointing to a lesion of the central or peripheral nervous system, together with the identification of ‘positive signs’ known to be specific for functional symptoms.” According to the review, “These positive signs are well known to all trained neurologists but their validity is still not established.”

The last sentence is interesting. It could perhaps be translated like this: “Although all trained neurologists know well that these positive signs identify people with a functional neurological disorder, we still have no actual evidence for that.”

As Daum et al recognized, that approach to medical care and treatment was no longer viable. “In the era of evidence-based medicine however, clinicians are facing a lack of proof regarding the validity of those clinical ‘positive signs,’” the authors noted. Hence, their decision to conduct a review of studies of the various signs for a range of FND presentations—functional weakness, functional sensory disorders and functional gait disorders.

After surveying the literature, the authors identified eleven studies that provided “some degree of validation” for 14 clinical signs. Ten of these studies included 23 or fewer subjects identified with FND. In ratings of study quality per the American Academy of Neurology’s classification system, nine of them were designated as Class III–the third out of four grades of quality. Only two included blinding. None included information on the key metric of inter-rater reliability, which would have assessed differences in how clinicians interpreted the various signs.

According to the review, these clinical signs overall had low sensitivity–meaning they would miss many of those who supposedly suffered from the relevant ailment, in this case FND. In contrast, the review reported, the signs had high specificity–meaning those identified by positive results were likely to have the condition and not something else instead. But the review’s account of its own limitations made clear that the findings of high specificity could not be taken at face value.

As the authors wrote: “As no gold standard exists for functional weakness, sensory and gait disturbances, precise diagnostic criteria on how a diagnosis of functional disorder has been made are not always provided [in the studies reviewed] and wrong attribution of subjects could have occurred. More importantly and more likely, this could have introduced a circular reasoning bias (self-fulfilling prophecy): if the studied sign is also used in the diagnosis process, the reported specificity is overestimated.”

That’s a significant point. If a studied sign is used in the diagnostic process, the reported specificity is essentially meaningless—to refer to it as “overestimated” would be generous. What has been proven in that case is that the sign is positive in the same people in whom it was positive the first time around. And that’s about it.

For Hoover’s sign, Daum et al included five studies and reported a pooled specificity of 100%. The earliest study, Ziv et al (1998), noted that Hoover’s sign “has several obvious limitations,” including that “it is semi-subjective, it is not quantitative, and it lacks sensitivity.” The study, which included nine FND patients, tested a computerized, quantified version of Hoover’s sign that does not seem relevant to its performance during standard use in clinical care.

The second study, from Sonoo (2004), cited clinicians “who have stated that this test [Hoover’s sign] may give variable or equivocal results” and was designed to investigate a different clinical sign for functional leg weakness; the author called this the abductor sign. The study, which included 16 patients diagnosed with FND, reported that the abductor sign provided better results overall than Hoover’s sign. The 2022 BMJ article co-authored by Dr Perez highlighted the abductor sign, along with Hoover’s sign, as the two validated signs for leg weakness; the article cited no additional studies.

Tinazzi et al (2008), a “brief report” in the journal Movement Disorders, was a study not of Hoover’s sign but of a finger abductor sign for arm paralysis. However, most of the ten FND patients in the study also had leg paralysis, and Hoover’s sign was part of the neurological examinations. The fourth paper, Stone et al (2010), was a descriptive epidemiology study of 107 patients diagnosed with functional weakness at neurology clinics. The investigators found that 60, or 56%, had a positive Hoover’s sign.

The fifth and most recent study, McWhirter et al (2011), was published in the Journal of Psychosomatic Research and was the only one actually designed to assess the diagnostic value of Hoover’s sign as used in clinical practice. In the introduction, the authors explained the rationale for the study in light of the proposed DSM changes:

“In 1908 Charles Hoover described a physical sign of functional (i.e. psychogenic) weakness of the lower extremities. Hoover’s sign is commonly used as a test for the diagnosis of functional weakness. However, no studies have tested the diagnostic performance of this sign in unselected patients with neurological symptoms. In the next revision of DSM, reference to positive physical signs of functional weakness may be incorporated within the criteria for conversion disorder itself. Data on the specificity and sensitivity of Hoover’s sign are therefore important.”

This study was part of a larger investigation of 377 patients admitted to hospital for suspected stroke. All underwent a thorough neurological exam, which included Hoover’s sign. Subsequently, an expert panel rendered a “gold standard” assessment of whether these patients had FND. The analysis of the validity of Hoover’s sign was based on the results in 124 patients who presented with leg weakness, eight of whom had been given a diagnosis of FND by the expert panel and 116 of whom received other diagnoses.

Hoover’s sign was positive In five of the eight FND patients, negative in two, and uncertain in one. Since all five who had positive Hoover’s signs had been given a gold-standard diagnosis of FND by the expert panel, and none of the additional 116 had a false positive Hoover’s sign, the specificity of the test was 100%. With three of those with gold-standard FND diagnoses being negative for Hoover’s sign, the sensitivity was only 63%.

One obvious point—this study included a teensy sample of people with FND. Second, the expert panel had the Hoover’s sign results at their disposal when they were making their gold-standard diagnoses. Given that all five in the sample with a positive Hoover’s sign had understandably been assigned to the FND group, the study seems mainly to have confirmed that a first positive Hoover’s sign accurately predicts a second.

As did the 2014 review in which it was referenced, McWhirter et al acknowledged the dilemma posed by a study in which participants were possibly or likely selected using the diagnostic tool being investigated—a design that would introduce what the authors called incorporation bias. They also acknowledged potential bias from lack of blinding. Here’s the relevant paragraph from the section on study limitations:

“The examining neurologist was not blinded to the diagnosis of functional disorder, in general performing both the history and the clinical examination. Hence, their interpretation of Hoover’s sign may have been influenced by the preceding history. Incorporation bias is also possible as Hoover’s sign may have been interpreted as a positive feature of a functional disorder by the adjudicating panel, and used to determine the presence or not of a functional disorder. Lastly we were limited by the small number of patients with functional symptoms presenting to the study. Therefore our estimates of diagnostic performance have wide limits of uncertainty around them.”

The problem is you could fly a plane through the vast space left by these limitations. They make it very difficult, if not impossible, to know how much credence, if any, can be given the reported findings. McWhirter et al concluded:

“Blinded studies with larger numbers of patients with functional weakness and several observers could provide better estimates of inter-observer reliability and diagnostic performance of this and other signs of functional weakness.” 

One more small study…

So was McWhirter et al the last word on the validity of Hoover’s sign? Not quite. In the BMJ paper Dr Perez and a colleague published last year, Diagnosis and Management of Functional Neurological Disorder, the list of research on Hoover’s sign included a single additional study, from 2015. (The 2022 list did not include the first study listed in the 2014 review, Ziv et al. Perhaps the authors decided that a study of a computerized, quantified Hoover’s sign was irrelevant to current practice.) In the 2022 paper, when the results from the identified studies were pooled, the specificity for Hoover’s sign was reported as 99.5% and the sensitivity as 61%.

The 2015 study included data on multiple signs tested in a group of 20 FND patients, with data for Hoover’s sign available for 17 of them. Unlike McWhirter et al, this study did not explicitly indicate whether those conducting the initial neurological assessment used Hoover’s sign. However, given the sign’s venerable history, it seems probable or likely that it would have been included in the standard work-up of patients presenting to a neurology clinic with relevant neurological complaints. Moreover, the study provided inter-rater reliability results for many other FND clinical signs, but not for Hoover’s sign—despite McWhirter et al’s explicit call for just such investigations. Nonetheless, the study categorized Hoover’s sign as “highly reliable,” citing “strong validation” in “several previous studies.”

That seems to be the extent of the data on Hoover’s sign. Perhaps it is true that a positive Hoover’s sign is highly specific and always or almost always indicates FND; I’m not a clinician and obviously can’t answer that question from personal experience. But as a journalist and public health academic I can read epidemiology papers, and the data on offer in these very few studies fails to make much of a case. The research is fraught with issues, including minuscule samples of FND patients and multiple forms of bias. It does not offer convincing or impressive support for bold assertions about the validity—and in particular the specificity—of Hoover’s sign. That doesn’t make the assertions–grounded in decades of authority from traditional practice–wrong. But it does mean there isn’t much proof to back them up.

Neurosymptoms.org, a popular site for FND patients and others maintained by a top FND expert, has sought to address the question of the reliability of the signs. The site acknowledges some issues and interpretive challenges, but also seeks to offer reassurance that the signs—and especially Hoover’s sign—have proven in studies to be sufficiently discriminating for the job. Here’s a key paragraph:

“For FND, each of the signs…has a varying degree of reliability. Studies looking at them show that they can discriminate between patients who have functional leg weakness and patients who have other neurological diseases, even when doctors don’t know what the diagnosis is, in advance. Some of them, like Hoover’s sign, perform well in these tests and for others we have less data or there needs to be more caution.”

This is obviously not the full background on Hoover’s sign. As far as I could find, neurosymptoms.org does not explain that Hoover’s sign, which is said to warrant less caution than other signs, was investigated in patients after it had definitely or likely been part of their diagnostic work-up. And it doesn’t mention that the state of data on Hoover’s sign is basically where it was in 2011 when McWhirter et al called for larger and more robust validation research—including investigations of inter-rater reliability—to supplement findings derived from that study’s sample of eight FND patients.

Where are these larger and more robust studies of Hoover’s sign? Why haven’t they been conducted in the last dozen years, if not by the authors of McWhirter et al than by others in the field? And is the research into the discriminatory value of other FND clinical signs any more persuasive than what’s available for this poster-sign?

(Originally posted on Virology Blog.)

#2 #fnd #functional-neurological-disorder

https://trialbyerror.org/2023/05/22/questions-about-the-prevalence-of-functional-neurological-disorder-and-the-research-on-hoovers-sign-for-functional-leg-weakness/

Today is #FNDAwareness Day. Not unlike long term outcomes of #necrotizingenterocolitis, if patients want to find a cure or proper treatment for FND, we have to share our experiences, raise awareness, & hope we can inspire others to share. I am finding ways to manage, but what I really need is access to help so I can have the future every young person deserves.

#functionalneurologicaldisorder #raredisorder #neurologicaldisorder

Thank goodness #wegmans has seating on the upper level. I'm having a bad flare-up so I'm sitting while my wife finishes shopping. Just another day with #FND. #FunctionalNeurologicalDisorder

Thank goodness #wegmans has seating on the upper level. I'm having a bad flare-up so I'm sitting while my wife finishes shopping. Just another day with #FND. #FunctionalNeurologicalDisorder

Thank goodness #wegmans has seating on the upper level. I'm having a bad flare-up so I'm sitting while my wife finishes shopping. Just another day with #FND. #FunctionalNeurologicalDisorder

Thank goodness #wegmans has seating on the upper level. I'm having a bad flare-up so I'm sitting while my wife finishes shopping. Just another day with #FND. #FunctionalNeurologicalDisorder

#FND #FunctionalNeurologicalDisorder
#Neurology

Why functional neurological disorder is not feigning or malingering | Nature Reviews Neurology
https://www.nature.com/articles/s41582-022-00765-z

#FND #FunctionalNeurologicalDisorder
#Neurology

Why functional neurological disorder is not feigning or malingering | Nature Reviews Neurology
https://www.nature.com/articles/s41582-022-00765-z

#FND #FunctionalNeurologicalDisorder
#Neurology

Why functional neurological disorder is not feigning or malingering | Nature Reviews Neurology
https://www.nature.com/articles/s41582-022-00765-z

#FND #FunctionalNeurologicalDisorder
#Neurology

Why functional neurological disorder is not feigning or malingering | Nature Reviews Neurology
https://www.nature.com/articles/s41582-022-00765-z

Week two of my time at the #FND clinic is up and here are my thoughts.

https://www.anthonyarblaster.com/post/week-2-fnd-clinic

#ChronicIllness #FunctionalNeurologicalDisorder #NHS