Trial By Error: Questions About the Prevalence of Functional Neurological Disorder and the Research on Hoover’s Sign for Functional Leg Weakness

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, 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,, which notes only 209 out of 3781 patients–that is, 5.5%—had “clear FND.” Hm. attempts to address these inconsistencies with some serious post-hoc re-interpretation and theorizing. Besides those with “clear FND” In Stone et al, notes, “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, 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 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.


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.)


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., 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, 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?

27 thoughts on “Trial By Error: Questions About the Prevalence of Functional Neurological Disorder and the Research on Hoover’s Sign for Functional Leg Weakness”

  1. So it looks to me like the old diagnostic criteria (including dx by exclusion) have been dumped in favour of diagnosis via signs that may not be up to scratch? Have I got that right? If so, what does that mean for the safety of FND diagnoses? I think a lot of people, including me, have probably assumed that diagnosis of FND via the positive signs was a good step, but if the signs are unreliable (aren’t as specific for FND as we’ve perhaps been led to believe) then I imagine that the change to the DSM could mean more patients being misdiagnosed because they’re no longer being thoroughly investigated to exclude other conditions. If that’s the case, then safety (or not) of diagnosis for neurology patients (or at least those who lack straightforward symptoms) might well now hinge on the specificity of these signs and how well (or not) they’ve been validated. Is that a fair assessment?

  2. Alicia Butcher Ehrhardt, PhD

    Wondering why the errors are always in their favor.

    And, of course, if one of these papers gets corrected, it never seems to propagate to all the others that DEPEND on the error being true.

    And that they fight so hard not to have to admit the error.

    BTW, you have a small typo: “This lengthy explanation confirms the hey point.” I think you mean ‘key’ point.

  3. George Bailey

    As someone who was misdiagnosed with FND for five years based on the inability of neurologists to distinguish between apraxia and Hoover’s sign, I’m thankful to Tuller for getting into the weeds with the research. Fortunately the apraxia diagnosis did come!

  4. Barbara McMullen

    I find this paragraph confusing: “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.”

    Does this mean that they can diagnose FND based on physical symptoms that don’t match another disease without the need to prove psychological symptoms? If so, how is this better than the previous guidelines?

  5. Barbara McMullen said:
    ” Does this mean that they can diagnose FND based on physical symptoms that don’t match another disease without the need to prove psychological symptoms? If so, how is this better than the previous guidelines?”

    I believe it does – well it seems that they’ve removed the requirement for finding any psychological symptoms/a psychological trigger, I assume because they were struggling to find any in 20% to 70% of patients, (that’s from them, not me). So now it appears to be down to these positive signs or possibly them deciding there’s some other sort of incongruency/inconsistency. I understand that diagnosis by exclusion has been thrown out, so, while that might not have always been done that well in the past, it appears that patients no longer have the security of knowing that all other known conditions should have been excluded, and I imagine that’s how the FND construct is so attractive to healthcare providers because it can save them lots of money in ‘unnecessary’ investigations. What does it matter if patients are being misdiagnosed? Who cares?

  6. I should add to my previous comment – it doesn’t look better now to me than the previous guidelines, it looks far more risky. Hasn’t diagnosis by excluding everything else (so extremely thorough investigation) now been replaced with tests (their signs) that haven’t been properly assessed or validated? I think that’s what this blog is telling us. If so, that seems absolutely crazy. Would that be done for any other disease/condition? Would existing diagnostic criteria be switched for tests that that need further evaluation/aren’t robust? I always thought diagnosis by exclusion was daft, but this appears plain reckless.

  7. Mike Fraumeni

    Excellent analysis I will say. Thank you. Please pass this information along to anyone that may be interested with children that are showing chorea deemed as “must be psychogenic”:
    “The most common error in the setting of chorea and dystonia
    is to wrongly assume the problem is psychogenic. The emotional
    lability the restlessness, the facial grimacing, the motor
    impersistence, and the dancing quality of the movements can
    all lead to chorea being misdiagnosed as a psychogenic
    problem. Sydenham33 recognized this more than three centuries
    ago: “If any vessel filled with drink be put into his hand,
    before it reaches his mouth he will exhibit a thousand
    gesticulations like a mountebank… as if he were trying to
    amuse the spectators by his antics.”
    Source: Grattan-Smith P. Psychogenic movement disorders in children. J Pediatr Neurol 2015;13:180–185.

  8. Mike Fraumeni

    Yes CT and BM, these new guidelines certainly can make it appear that diagnosing CD/FND is more accurate and evidence based but in fact it is making it easier now for neurologists to discard patients they don’t want to follow and punt them off to psychiatry much more easily. As a leading psychiatrist, Dr. Allen Frances Professor, Chairman Emeritus of the Department of Psychiatry and Behavioral Sciences at Duke University School of Medicine mentions on Twitter, post from Feb. 24/2022:
    “Awful problem with DSM-5 ‘Functional Neurological Disorder’ is not how it’s defined, but how used.
    Vanishingly rare if strict DSM definition is closely followed.
    But very common when used carelessly (especially in neurology) to blame all unexplained symptoms on psych disorder.”

  9. It’s deeply concerning that a leading hospital in the UK has apparently been persuaded to adopt a strategy of limiting investigations based on this ‘functional’ dogma. (A perfect storm, one might imagine, when the NHS is on its knees). I see that a neurologist has commented on what David has said in relation to his blog - and claims that misdiagnosis rates are low - , but the study they put forward to evidence this was of patients diagnosed BEFORE the changes to the DSM, patients who would most likely have been diagnosed by exclusion as well as the signs. I don’t know of any study on FND misdiagnosis rates for patients diagnosed since the change to the DSM. I’d argue that it’s reckless to throw out dx by exclusion for unreliable signs that the neurologist appears to admit could do with further evaluation, and doubly reckless not to monitor misdiagnosis after doing that.

  10. Mike Fraumeni

    Yes CT and in my experience, I have been dx’ed with FND, the neurologists and psychiatrist they sent me to diagnosed me within a few months and once you have a diagnosis of FND, it is difficult to have it overturned for a variety of reasons which is a different discussion. Now consider, as in my case, I had a leading geriatrician examined me for a research study for dual-tasking and progression to mild cognitive impairment, not clinical, and mentioned that I didn’t qualify for the research study as I had parkinsonism symptoms which were an exclusion criteria for the study. However I mentioned this to the neurologists and psychiatrist I saw but they didn’t seem to recognize this assessment at all. As I say, this is a world leading geriatrician with a proven track record and is on the panel of the Ontario Neurodegenerative Research Disease Initiative as is the lead for the gait platform. Disgusting. Moreover, why wouldn’t neurology want to follow me, at the least, with knowing this information for Parkinson’s disease for example, a clinical diagnosis that currently has no clinical biomarker:
    “The time needed to reach a final diagnosis in the clinical setting was 2.75 years in 95% of patients presenting initially with parkinsonism and/or tremor.” Source: Rossi M et al. How much time is needed in clinical practice to reach a diagnosis of clinically established Parkinson’s disease? Parkinsonism & Related Disorders, Volume 92, November 2021, Pages 53-58

    Furthermore with the advent of advanced genetic testing now becoming more readily available, without such testing in many cases how does a clinician know that a FND diagnosis is correct? The field of Neurogenetics is developing rapidly with the rise of advanced technical developments. Example:
    “Unmasking Rare Diseases – Five and a half years ago, Andrea, now a teenager, landed in Dr. Fatemi’s clinic with what she’d been told by another neurologist was a conversion disorder.
    For the previous two years, her ability to walk had progressively worsened, her left leg bowing outward because her left foot wouldn’t rest flat on the floor. She’d been advised against medical treatment because, she was told by her doctor at the time, the condition was all in her head, her mother says.
    Unconvinced, Andrea’s mother took her to Kennedy Krieger. There, they met with Dr. Fatemi and Julie Cohen, a genetic counselor with Kennedy Krieger’s Division of Neurogenetics.” …
    Source: Kennedy Krieger Institute, Baltimore, Maryland.

  11. Mike Fraumeni

    And just to reiterate concerning movement disorders and genetics, I wonder how Jon Stone and his colleagues are going to deal with this in light of David’s analysis above and incidence rates of FND, this the motor subtype of FND:
    “Genetics are fundamental to understanding the pathophysiology of neurological disease, including movement disorders. Genetic testing in clinical practice has changed dramatically over the last few decades. While the likelihood of establishing an etiological diagnosis is greater now with increased access to testing and more advanced technologies, clinicians face challenges when deciding whether to test, then selecting the appropriate test, and ultimately interpreting and sharing the results with patients and families” …
    Source: Kalia LV et al. Genetic Testing in Clinical Movement Disorders: A Case-Based Review. Semin Neurol. 2023 Feb;43(1):147-155.

  12. I suspect that FND misdiagnosis rates would be found to be considerably higher if patients, (particularly those who leave with their trust in medics in tatters), were traced and followed over a longer period of time than they have previously been.

  13. Mike Fraumeni

    Yes CT and a functional presentation, as they mention below part of a prodromal phase which I’ve read in the literature can last for years or decades with some neurodegenerative diseases. This, for example, with Parkinson’s disease:
    “A subtype of PD with functional neurological features is familial in one-fourth of cases and associated with more psychiatric than motor disability and greater use of diagnostic and healthcare resources than those without functional features. Functional manifestations may be prodromal to PD in one-third of patients.”
    Source: Wissel BD et al. Functional neurological disorders in Parkinson disease. J Neurol Neurosurg Psychiatry. 2018 Jun;89(6):566-571.

  14. I suppose it’s a question of whether one chooses to believe in any of this ‘functional’ stuff. I don’t. I view the whole FND endeavour as a group of researchers desperately trying to cling in some way to their old hypothesis because they can’t quite bring themselves to admit that all their previous work that they believed in so strongly was wrong. Instead they seem to tweak this and wriggle towards that and attempt to cover themselves in case one day it all comes tumbling down. I have no problem with scientists saying “We got this wrong, our hypothesis has been shown to be false so we’ll work on a new one and test that”. They are to be admired for their honesty and their dedication to discovering the truth. But that’s not what I see going on here. So many papers open by equating ‘functional’ with ‘conversion disorder’ without spelling out that the conversion hypothesis doesn’t stand up – that a sizeable proportion of patients diagnosed with FND will have no psychological issues and that association does not equal causation for those who do. So many papers point medics to women being the predominant group without flagging up that a self-fulfilling prophecy based on physician bias is highly likely to be at play, and that women have a different physiology to men and have been under-researched and gaslighted with regard to their health problems since time immemorial. FND experts now say that doctors who are diagnosing by exclusion or by psychological symptoms/issues are doing it wrong, but they have been taught to do this by those experts before those experts had their great awakening, perhaps better described as a blink-and-you’ll-miss-it snooze reset. The doctors are simply still doing what they’ve been taught to do over decades because nobody has come out in public and held their hands up and loudly declared – “sorry guys, all that conversion stuff was Freudian twaddle, completely wrong, we really messed up back there”.

    I saw a social media exchange between David and someone else in relation to this post, (or something he had posted in relation to this post). They seemed to be asking why he was focused on FND and why couldn’t he just keep to ME/CFS and leave the FND community alone. I’m not going to answer for him – he answered very well himself – but I will say that I’m exceedingly grateful to him for blogging about the problems with FND. Doctors, including neurologists, have, at various times, tried to label me with ME, medically unexplained symptoms (MUS) and FND. I’ve not allowed any of these labels to stick because they were based on no good evidence and were clearly wrong – I surmised that they were just being used as a convenient waste basket to throw me in, (I’d argue a waste basket provided to doctors by the BPS mob). But if I hadn’t had some background knowledge of what real ME looks like, and if I hadn’t had a scientific background which meant I could read the old website and not be taken in by it, I dread to think where I’d be right now…. but I could hazard a guess. I imagine I’d likely have been directed to CBT and, being quite a compliant person, I’d probably have gone there, and it wouldn’t have helped. I’d probably then have been prescribed antidepressants which most likely wouldn’t have worked either but may well have screwed up my mind and caused all sorts of awful bodily symptoms too, (antidepressants having had some pretty serious consequences for members of my family – I recognize they can be helpful to some depressed people). Then I could have decided to withdraw from them only to find myself in an increasing hell that doctors refuse to recognize. Or maybe I’d have been prescribed graded exercise/physio, but I’ve tried both at length before and they either didn’t work or made me worse. Instead, I decided to walk away. That’s meant no good evaluation or healthcare and no validation but, given the woeful options, I think I made the right choice because some of my symptoms, (not all by any means), have eased with time. A few, with the benefit or time, gradually lessened and completely resolved and I’ve gained my own understanding of what caused them and what I should avoid in future. When doctors don’t have the time or can’t be bothered to unpick what’s going on, you’ve no choice really but to do it for yourself or live in ignorance.

    So for the exact same unexplained symptoms, I could have been misdiagnosed with ME or FND or MUS. (I include MUS because the BPS mob paint that as a mental health disorder and there is no evidence that my symptoms are related to my mental health. From now on I think I’ll refer to that as MH-MUS, to distinguish it from it being symptoms that haven’t yet been medically explained.) There will be lots of patients who are currently misdiagnosed with ME, FND and MH-MUS. I’d have thought that members of the FND community would be keen that patients aren’t misdiagnosed and that diagnostic criteria are robust so that misdiagnosis is minimized. They shouldn’t want people like me confusing the research picture or giving advice on patient forums about what helped them to feel better or recover (however well intentioned). They shouldn’t want FND proponents/experts claiming in the FND literature that the specificity of a diagnostic sign for FND is 100% because other FND experts haven’t been clear enough about what the true specificity of the sign is or the significant limitations of the studies that were supposed to determine it. And they shouldn’t want the prevalence of their disease/condition to be inflated to include patients who don’t meet its current diagnostic criteria unless, of course, they’re trying to unfairly grab research and service funding off other diseases. Every unhealthy person wants a diagnosis, but they need and deserve to get they right one.

  15. Mike Fraumeni

    Excellent read CT. As for myself, like yourself, I don’t believe that the diagnoses of FND is correct for what I’m experiencing and I am certain that neurologists have been disingenuous with this diagnosis for a few reasons. And personally speaking, if I actually did believe I have this DSM mental illness diagnosis of FND, I would argue that indeed I do have a psychiatric mental illness without question.

    Not sure you seen this from the APA site but this is how CD/FND is referred to:

    ‘In Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the term “Functional Neurological
    Symptom Disorder” was added in parentheses after the DSM-IV term “Conversion Disorder.” In the
    DSM-5 Text Revision (DSM-5-TR), the terms are reversed so that Conversion Disorder is in
    Rationale for Change
    The decision to reverse the parenthetical order for the disorder was based on the following reasons:
    • Functional neurological (symptom) disorder is the term of choice for the international research
    and patient community.
    • Conversion disorder is falling from use by researchers and clinicians in the field.
    • Conversion disorder is not an etiologically neutral term


  16. Mike Fraumeni

    And if I may, just one other thought concerning anyone diagnosed with any DSM label. I would suggest that anyone not believe they have such a DSM diagnoses for their symptoms. Why? Because if you believe in the diagnosis and whatever therapies they try and if none work to your satisfaction, guess what? You’re hung out to dry with a psychiatric mental illness diagnosis most likely for the rest of your life. Personally I would suggest that anyone tell them that you most likely have a brain condition that is most likely a white matter brain condition as Dr. Henry Nasrallah mentions here. And then perhaps they may send you to a cognitive/behavioural neurologist which might make the best sense if you want to be followed by a medical professional:

    — Psychiatry is Neurology: White matter pathology permeates psychiatric disorders —

    “Ask neurologists or psychiatrists to name a white matter (WM) brain disease and they are very likely to
    say multiple sclerosis (MS), a demyelinating brain disorder caused by immune-mediated destruction of
    oligodendrocytes, the glial cells that manufacture myelin without which brain communications would come to a standstill.
    MS is often associated with mood or psychotic disorders, yet it is regarded as a neurologic illness, not a psychiatric
    Many neurologists and psychiatrists may not be aware that during the past few years, multiple diffusion tensor
    imaging (DTI) studies have revealed that many psychiatric disorders are associated with WM pathology.1
    Most people think that the brain is composed mostly of neurons, but in fact the bulk of brain volume (60%) is comprised of WM and only 40% is gray matter, which includes both neurons and glial cells (astroglia, microglia, and oligodendroglia). WM includes >137,000 km of myelinated fibers, an extensive network that connects all brain regions and integrates its complex, multifaceted functions, culminating in a unified
    sense of self and agency.” …


  17. Mike Fraumeni

    Also in relation to Dr. Nasrallah’s article above, this would seem like an excellent proposal in the fields of psychiatry and neurology training. From Medscape, first link but if anyone doesn’t have a Medscape account the second link is to the primary article mentioned:

    “New Proposal for a Single Neuro/Psych Residency Program – A group of pre-eminent neurologists and psychiatrists have developed a proposal for a single neurology and psychiatry residency program.
    A residency in “brain medicine” would educate residents in both psychiatry and neurology and include 2 years of common and urgent training in aspects of neurology and psychiatry, followed by another 2 years of elective subspecialty tracks.”…
    “Time for Brain Medicine – Unprecedented knowledge of the brain is inevitably contributing to the convergence of neurology and psychiatry.” …

  18. Thanks Mike.

    I’m not sure how the last 2 bullet points about conversion disorder are supposed to be interpreted. Is the term ‘conversion disorder’ on the wane because researchers and clinicians no longer believe in it as a construct/hypothesis, or because they’ve realized that patients won’t engage with them if they use it? And what does it mean when it tells us that the term isn’t “etiologically neutral”? Are they admitting that ‘conversion disorder’ relates to the mind (or at least a dualistic switch between ‘mind’ and ‘body’) rather than to some indeterminate/fuzzy/fluffy intersection between mind and body? (Oh whoops, we just can’t seem to get away from that mind-body dualism, can we?!)

    The problem with ‘functional’ is that it has the potential to confuse people, but perhaps that’s why it’s been chosen? Many, as I did, grasp the distinction between an anatomical/structural cause that is visible at least with a microscope or via high-powered scans and a ‘functional’ one that affects the patient through the biochemistry or physiology of the body – the ‘hardware’ that you can see versus the ‘software’ that you can’t, if you like. But, from what I’ve read, FND/’conversion disorder’ proponents seem to have wrapped up a whole different meaning into their use of ‘functional’ by apparently subscribing to a belief system of mind over matter, (sorry, dualism again), and magical thinking and, if I’m not mistaken, arguing that if thought or mental stress can cause physical effects on the body -(exam stress causing people to run to the toilet has been quite often offered as an example, I think) – then a mind-based therapy should be able to reverse or help reverse any lasting damage to the body so caused. It’s a nice thought, but I don’t think biological systems are as simple as that. For a start, they might like to consider the concept of entropy. Yes, many biochemical reactions may be capable of working both ways, but it often requires a significant input of energy and/or the employment of enzymes to reverse the reaction. These are not likely to be on standby to leap into action at the behest of the patient or their therapist, no matter how positive the vibes that are sent in that direction. (I also wonder if they have perhaps chosen the word ‘functional’ so that when the causes of FNDs do turn out to be biochemical or physiological, as I believe they will, then they can hide behind it. Who knows?)

  19. Mike Fraumeni

    Yes CT, if the APA doesn’t “like” the term conversion disorder due to it not being “etiologically neutral” then why not discard this term or separate Conversion Disorder from Functional Neurological Disorder? Confusing.
    As you mention, perhaps the word ‘functional’ was chosen to confuse people, confuse people into thinking that their diagnosis isn’t a DSM mental illness diagnosis, but one would hope the medical profession wouldn’t be that manipulative. Or maybe they could be that manipulative! One author mentions, reference below, to quote “Because the term “FND” has been viewed unfavorably by some patients and clinical practitioners and whose treatment is not implied, the alternative term attentionally-modifiable disorder is proposed.” But organic diseases such as Parkinson’s disease for example are deemed to have some volitional control, therefore modifiable in some respects, in this study, reference again below, titled “Volitional Suppression of Parkinsonian Resting Tremor” … “We have observed in the clinic that a number of patients with Parkinson’s disease (PD) can suppress their tremor at will for brief periods, by conscious mental processes. To our knowledge, the ability to consciously diminish one’s resting tremor has not yet been reported nor assessed quantitatively.” …

    And yes, hiding behind it as a strategy. Yup, who knows.
    Mark, V. Functional neurological disorder: Extending the diagnosis to other disorders, and proposing an alternate disease term-Attentionally-modifiable disorder. NeuroRehabilitation. 2022;50(2):179-207. doi: 10.3233/NRE-228003.

    Blakemore, RL. Volitional Suppression of Parkinsonian Resting Tremor. Mov Disord Clin Pract . 2019 Jul 1;6(6):470-478. doi: 10.1002/mdc3.12801. eCollection 2019 Jul.

  20. Well, I can sometimes consciously reduce my blood pressure for a short time if I’m sitting quietly, redirecting my thoughts and breathing in a particular way. That’s clearly a physiological effect on the body but it’s not sustainable over a long time. I suspect that the body has probably evolved to produce short term responses (and symptoms) to stress and emotions, and we can perhaps consciously alter some things on a short term basis too. But long term, for long-term symptoms? I think that’s an extrapolation too far. I do believe that stress can bring out or exacerbate symptoms in someone who is (perhaps not knowingly) medically compromised in some way, so that it appears that their disease or condition has been caused by stress or some psychological trigger but instead they have a medical vulnerability that they weren’t aware of. I’m not a doctor, but I’m not convinced that doctors know any more than I do. It’s all about belief until science comes up with indisputable answers, and I don’t think we’re there yet.

  21. Mike Fraumeni

    Completely agree it’s about belief, just believe me because “I’m a doctor” sort of thing, I shalt not be questioned…. sort of mentality.

    I don’t ask that any doctor has the answers, as you say the science isn’t there yet. All I ask is that neurologists follow a patient presenting to them for a few years before punting them off for psychiatry to deal with because they can’t put a name next to their neurologically-presenting symptoms that don’t fit into a nice neat tidy box from their training background in neurology. You don’t need a psychiatrist to order or neuropsych assessment or administer the Montreal Cognitive Assessment Test for pete sakes.

  22. Marion Brown

    It would seem that FND is indeed being used – and this ‘diagnosis’ encouraged – as way to not recognise harm from ‘medical care’ of various sorts.
    Thanks to CT for touching on the issue of ‘the effects of medications’ – being the effects (and longer term effects) of taking medications and the serious issues (long unrecognised) around dependence and withdrawal.
    I have long wondered why the effects of ‘usual medical care’ part of the MECFS ‘treatment’ seems to be always overlooked? Antidepressants seem to have been the staple ‘usual medical care’ for decades…. as well as other dependence forming ‘medications’.
    Many previously healthy people are being ‘diagnosed’ with MUS and/or FND after developing neurological conditions following ‘treatment’ with antidepressants etc. I have written quite a lot about this – including an article which has just been published a s a chapter in a new book.
    New book: Withdrawal from prescribed psychotropic drugs:
    Article (now a chapter in above book): The patient voice: Antidepressant withdrawal, medically unexplained symptoms and functional neurological disorders
    Could FND be being used as a legal diversion from examining the harms of medicine?

  23. Marion Brown wrote:
    “Could FND be being used as a legal diversion from examining the harms of medicine?”

    I don’t know about a legal diversion but I suspect that some or many supposed FND cases may be due to side (or withdrawal) effects of prescription, herbal or illegal drugs that, in my experience, doctors rarely want to ask or know about. Am I right in thinking that ADRs have been flagged up as a possible cause to leaders in the FND field? If so, and if they’re still not emphasizing in their teaching that it needs checking out (and recording for research purposes) as a first port of call, then in my opinion they are letting their patients down very badly indeed. I mean, they should really have thought of that themselves – drug side effects should surely be at the forefront of every doctor’s mind when faced with unexplained or strange symptoms – but I don’t think they have any excuse if it’s been flagged up to them.

  24. Marion Brown

    CT writes: “Am I right in thinking that ADRs have been flagged up as a possible cause to leaders in the FND field? If so, and if they’re still not emphasizing in their teaching that it needs checking out (and recording for research purposes)”

    Please may I formally record here the following:

    Rapid responses published by BMJ:

    There has never been any acknowledgment or response from the BMJ itself (as commissioner of these major articles: ‘Recognising and explaining functional neurological disorder’, 2020 and ‘Diagnosis and management of functional neurological disorder’, 2022) or from the article authors (respectively Stone Burton & Carson – and & Aybeck & Perez).

    I can also confirm that in late 2020 we wrote formally to the ABN (Association of British Neurologists) raising our concerns over the omission of the ‘medication history’ (and adverse effects) in the BMJ Stone, Carson, Burton article ‘Recognising and explaining functional neurological disorder’, for which we had already had Rapid Responses published.
    The reply from ABN president David Burn was brief:
    “We thank you for your letter 20 November 2020. The Association of British Neurologists
    has no locus over ‘practice pointer’ review articles published by the BMJ, and
    correspondence over the manuscript in question should be taken up with them. That
    said, our informal understanding is that that particular article had a positive
    reception from FND patient charities who were also involved in the development of
    the manuscript.
    The framework proposed in the paper in question does allow for anti depressant
    withdrawal symptoms to be a trigger factor for the development of functional
    neurological disorder. However, we note that such disorders were prevalent prior to
    the first antidepressant in 1951.”

    We wrote further in reply – but there was no further response from ABN.

    Jon Stone and Alan Carson – as well as many of the FND ‘experts’ have active roles in the main FND Charities and FND society.

  25. Marion Brown

    As the BMJ Articles are not ‘open access’, I thought it may be useful to copy this extract from ‘Recognising and explaining functional neurological disorder’ (Jon Stone, Christopher Burton, Alan Carson) 2020 BMJ here:


    Education into practice
    – What is your attitude to patients with functional neurological disorder?
    – How much importance do you put on psychological features when considering a diagnosis?
    – How do you explain that tests you are ordering are likely to be normal?
    – Think about a recent patient you saw with FND: how did you explain their symptoms or diagnosis to them? What might you do differently next time?

    How patients were involved in the creation of this article
    The article was reviewed and improved by representatives from five patient organisations: FND Hope, FND Hope UK, FND Action, FND Dimensions, and FND Friends. They made many incorporated suggestions, especially focusing on language that promotes an aetiologically neutral approach which is not blaming or presupposing psychological causation and emphasising need to evaluate new symptoms without prejudice.

    We thank Catherine MacEwan for assistance with figures.

    Contributors: JS drafted the manuscript, CB and AC revised the script. The manuscript was reviewed by Dawn Golder (FND Hope UK), Bridget Mildon (FND Hope), Emma Clark (FND Friends), Kim Hearne (FND Action), and Steven Webster (FND Dimensions).

    Funding: JS is supported by an NHS Scotland Career Fellowship.

    Competing interests: We have read and understood the BMJ Group policy on declaration of interests and declare the following interests: JS and AC are employed by NHS Lothian. JS and AC carry out independent expert testimony work for personal injury and medical negligence claims. JS receives royalties from UpToDate for articles on functional neurological disorder. JS runs a free non-profit self-help website,, which is mentioned in the article. AC receives fees as an associate editor of Journal of Neurology, Neurosurgery and Psychiatry. CB is employed by the University of Sheffield and carries out sessional clinical work as a general practitioner. CB receives royalties from Wiley for one book.

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