Trial By Error: Mt Sinai’s David Putrino on Long Covid and Functional Neurological Disorder

By David Tuller, DrPH

David Putrino is a neuroscientist and physical therapist at New York’s Mt Sinai Health System, where he is director of rehabilitation innovation. Over the last three years, he has worked extensively with patients experiencing prolonged symptoms after an acute bout of Covid-19, or what has become known as long Covid (LC). Last spring, I interviewed him about long Covid and ME/CFS. On Monday, he posted a Twitter thread that began with this: 

“We are in our fourth year of work to understand #LongCovid and we now know things about it thanks to science. After being told again by a quasi-well meaning, if uninformed, clinician that LC is just functional neurological disorder (FND). Here’s a thread on why LC IS NOT FND.“ 

The argument that people whose symptoms fall under the LC umbrella might have FND or related functional disorders has been presented in the medical literature. High-profile news stories in New York Magazine, The New Republic, and elsewhere have amplified the notion that many people diagnosed with LC are actually suffering from functional symptoms attributable to pandemic-related stress, depression, and anxiety. (“Functional” has gradually emerged as the replacement term for what would formerly have been called “psychosomatic.”)

The first tweet in Dr Putrino’s thread racked up 380,000+ views and was retweeted more than 1000 times. A few responses were critical, including this counter-thread from an FND patient who tweets as @FNDPortal. (Incidentally, @FNDPortal wrote this compelling account of the history of FND combined with a harrowing and personal description of the experience of illness.)

I spoke with Dr Putrino earlier today about his thread and some of the push-back it received.

10 thoughts on “Trial By Error: Mt Sinai’s David Putrino on Long Covid and Functional Neurological Disorder”

  1. Excellent. This was so good to watch. Thank you David and David. It’s important that FND patients are properly diagnosed and know the positive sign/s by which they’ve been diagnosed… and it’s also important that LC patients are properly assessed and investigated for the many different problems that the virus may have caused/triggered throughout their bodies. The last thing we need is bucket diagnosis, but I fear that a lot of that is going on, especially since health service providers (in the UK at least) seem to have been persuaded that FND and functional disorder diagnoses have the potential to save them considerable amounts of money.

  2. You both are an oasis of sanity for people who are being marginalized and who are sometimes losing hope of getting any help. Dr. Putrino’s twitter thread was an outstanding and digestible synopsis of the scientific literature on LC. If it were FND, and there were treatments that worked, I think there would be little resistance to considering it. Thank you.

  3. Hello David,

    I am FND Portal – the person whose “pushback” Putrino responded to here.

    I’d like to thank you for facilitating a remarkable conversation, in which Putrino declares that it’s not necessary for him to listen to people with FND or consider our perspectives when making public statements about our disorder. That’s a remarkable level of confidence, not to need to check in with people who have FND when we tell him that we’re concerned his statements are medically inaccurate and likely to cause harm.

    But is this confidence warranted?

    First, let me clarify my own position on Long COVID. I believe that Long COVID, as you suggested in this interview, is not a singular entity but a collection of illnesses triggered by the coronavirus. Many will be familiar – ME, POTS, and so on – and others might yet be unique to LC. I don’t think this is yet known and generally prefer to wait for more data to come in before diving too deep into the nosology.

    But let’s get to the FND part. From my perspective, FND is a fully physical, organic, and biological disorder. It is a disruption of functional network relationships in the brain. It produces symptoms that may overlap with other disorders but in many cases are fully distinct. While it may interact with elements of psychology, I don’t consider it to be a “mental disorder” in the traditional sense. I consider it to be a full-brain disorder that doesn’t fit neatly into either neurological or psychiatric categories, because the brain itself doesn’t (these categories were themselves created in the 1800s as scientists grappled to understand the brain’s function at levels of scale).

    It is the cause of real disability, despair, and pain, as I have experienced in my own life. Thanks to FND, and the many years I went undiagnosed, I lost my ability to walk, speak, and use my hands. These things had to be rehabbed over many years, often in excruciating pain, and with great difficulty. I am still not completely able-bodied, but grateful for the recovery I’ve managed so far. My personal view of FND emerges from a combination of lived experience, and (if I may be blunt) knowing the scientific literature really, really well.

    I criticized Putrino’s initial Twitter thread because his framing suggested to me that he doesn’t understand that FND can co-occur with other disorders, that it’s commonly triggered by physiological disruptions including injuries and viral illness, and it has a specific physiological basis that can be differentiated from other disorders. I was concerned that his highlighting of potential viral persistence as the sole mediator of LC symptoms might miss the fact that 1) the LC label itself may be overly broad, capturing a variety of conditions and mushing them together in an unhelpful way (which might might include some cases of FND!) and 2) FND could also occur secondarily to viral infection, which would put FND on equal footing with any number of other physical conditions which might be triggered by the virus and subsequently subsumed under the LC umbrella. Putrino has addressed some of that here, but that was the basis of my original objection.

    Rather than responding to my thread, or DMing me or the FND society privately, as I invited him to do, Putrino apparently decided to talk to you. I’m glad he did, because in this video he inadvertently reveals that he has no idea how FND diagnosis is actually done. First, he describes symptoms like weakness as “diagnostic criteria” for FND. This is false. FND diagnosis is not done on the basis of presence or absence of symptoms (he’s quite correct that tremors, for example, show up in other conditions like Parkinson’s and Essential Tremor). It’s done on the basis of the *behavior* of those symptoms – which map onto known properties of the neural systems, including the salience network, that are shown to be altered in fMRI studies of FND.

    He further expresses doubt about ability to differentiate between essential and functional tremor, functional weakness vs spinal injuries, and so on. This despite the fact that there are highly sensitive and specific clinical tests that can differentiate these FND symptoms from other conditions, and some of which (like entrainable tremor) are essentially 100% specific because they occur in no other condition.

    But just because Putrino doesn’t know something, doesn’t mean *nobody* knows it. In fact, there are clinicians that do these kinds of tests all the time, and who can differentiate with a high degree of accuracy between FND and other neurological and neuromuscular disorders.

    What this tells me is that despite Putrino’s general argument, which sounds ok on the surface – that we need not think about FND because it’s diagnostically fuzzy, and anyway doesn’t the virus explain it better? – he has not incorporated ACTUAL SPECIFIC TESTING FOR FND IN HIS CLINIC. That means his entire argument goes out the window. There is just no way that Putrino can say categorically that FND isn’t present in Long Covid cohorts, because he is ignorant of the kind of testing that would be necessary to determine this! He just said so!

    Note elsewhere in the video he says “I have worked fairly closely with folks with functional neurological disorder diagnoses.” He doesn’t say he’s ever treated them. He doesn’t describe any current best practices for rehabilitation, or go into any detail on how the neurobiology of that treatment is thought to work. He doesn’t say he’s actually ever helped anyone with FND.

    Instead, he goes on to say, “I am familiar with the conceptual framework around diagnosing and measuring symptoms of FND,” and then goes on to show that he is not in fact familiar with these things. Again, *symptoms* are not inclusion criteria for FND – the *nature* of neurological symptoms is. This is basic stuff that is now being taught to medical students. Idiopathic dystonia is not the same thing as FND dystonia. I could go on.

    I have to credit you with displaying a better understanding of FND than he does here. I just wish, again, that Putrino had showed the humility of consulting subject matter experts, including people with FND, before making statements that show that he’s not up on the science. I can’t help but notice that he didn’t really answer your question about functional overlay.

    More concerning yet is the idea that he just doesn’t *need* to know the things we know. I would never, ever make blanket pronouncements about someone else’s disorder without taking the time to consult with them, get the understanding of the community, and make sure I’m not making some frankly pretty rookie mistakes. David apparently thinks his neuroscientific background is sufficient to bypass that, but it’s not. It’s a central aspect of respecting disability communities, and had he shown it would demonstrate the kind of epistemic humility I would want to see in a clinician.

    What a missed opportunity for mutual understanding. What hubris. What tragedy.

    References, courtesy of Dr. David Perez on Twitter earlier today:

  4. Perhaps online critics of David Putrino could explain how hyperventilation, fibromyalgia, anxiety, depression, and excess alcohol (to name just a few of the problems that were included in the 16% group* that supposedly makes FND the “second most common” cause of referral to neurology outpatients) count as FND? What exactly are their positive signs? I’d dearly love to know.
    (*see - )

  5. The issue, as I see it, is this. While clearly stating that FND must now be positively identified, some, (or actually a fair number), of FND proponents seem to want to also make a metaphorical ‘land-grab’ of lots of things that aren’t positively-identified FND (like Long Covid). Ensuring that FND gets the neurology research and service funding that should accompany a condition or group of conditions that makes up maybe 6% or 7% of neurology referrals doesn’t seem enough for them, they appear to want more and it looks as if they see no problem with including patients in their prevalence statistics for whom there is likely no evidence (or accompanying signs) of a ‘top-down’ condition, (as Putrino describes it, I think).

    I imagine that hyping of the prevalence of FND would be highly likely to result in other neurologists getting the wrong end of the stick and incorrectly diagnosing patients with FND who have no positive signs of it….well that and the lack of distinction in FND literature between functional neurological disorder (FND) that is diagnosed via positive signs and functional disorders generally in neurology (or other specialisms) which are less well defined and may or may not have any positive diagnostic signs associated with them. While, on occasion, it’s possible to pick out the difference in what FND proponents write or say, (like in the presentation available here –, quite often it isn’t so clear (well not to me anyway) and the blurring of the meanings of these terms seems almost deliberate. It’s no surprise to me that doctors get it wrong.

    When FND proponents/experts claim, as they often do, that FND is the “second most common” condition seen in neurology outpatient clinics, or that it comprises 16% of neurology referrals, aren’t they being disingenuous if they can’t tell us what the positive signs were for all the patients in the 16% group of the cited study? What were they for those with anxiety, depression, excess alcohol or hyperventilation, for example? From memory, David (Tuller) raised this issue with some of them quite some time ago but, unless I missed it, there’s been no update since, and I’m guessing that’s because he’s had no response from them. Is there any chance of an update, David? Has anyone got back to you and explained why the 16% or “second most common” claims for FND prevalence are correct? And have they told you what the positive signs were for all the patients in that 16% group?

    I can’t see that Putrino has said anything in this interview that FND proponents/experts could possibly have a problem with. Didn’t he explain that some patients who believe or have been told that they have Long Covid could have FND as well or instead, but that FND diagnosis requires evidence of a top-down condition? I thought he did. How is that wrong? Isn’t he just saying that a lot of LC patients have no indication of a top-down mechanism, no positive signs, (but with evidence instead of direct viral involvement in organs and systems), and that they therefore shouldn’t be wrongly diagnosed with FND? Isn’t that exactly what FND experts have said? Hasn’t Jon Stone said to the effect that diagnosis not done on the basis of positive signs is bad medicine?

    The FND experts have redefined FND (from ‘conversion disorder’) but it seems to me that some of them aren’t too comfortable with the redefinition. Is this because it’s no longer good enough to claim that patients are suffering physical symptoms because of stress or trauma that they’ve been through – rather positive signs must now be demonstrated for a diagnosis of FND? It looks like FND is becoming yet another disorder that started out as being deemed psychosomatic, with patients being gaslighted, but that will end up with a clear biomedical explanation. Some FND proponents/’experts’ don’t seem to want to let go of the past. It looks as if they still want to be able to attribute medically unexplained symptoms to some psychological problem (and confusingly call it ‘functional’) without any evidence that that is the cause. It’s their lack of clarity that is the issue, I think, but they seem to want to blame everyone else.

  6. FND Portal – this is a genuine request:

    As you know the FND literature so well, could you perhaps explain the 16% (“second most common”) prevalence figure that I outlined in my first comment? That is, what were the positive signs for all the patients in the 16% group of the Stone et al 2010 paper? FND experts don’t seem to want to engage on the issue but it’s pretty important. A prevalence of 16% shouldn’t be claimed for FND if the patients in the 16% group weren’t all positively identified with FND, should it?

  7. I read and have now reread FND Portal’s comment above. I don’t know exactly what David Putrino’s background is but I understood (perhaps wrongly?) from the video that he is a neuroscientist rather than a neurologist and also that he is or has been involved with the rehabilitation of patients, particularly those with motor problems? I interpreted Putrino’s comments as being largely about the current state of affairs with doctors diagnosing or labelling patients wrongly in different ways, rather than them being about what should be. I can’t remember now if he specifically mentioned the requirement for FND patients to be diagnosed via positive signs, but I’m 99.9% sure that he distinguished the top-down mechanism thought to be behind FND from the indications of bottom-up mechanisms that are seen with symptoms and pathology in LC patients. My impression was that he had made a considerable effort to understand FND and the proposed mechanism/s behind it and was informed by that when working with FND patients. If patients come to him (or any other rehabilitation specialist) as already diagnosed with FND, is he expected to test them all over again and re-diagnose them if the diagnosis is wrong? Should rehabilitation folk assume that neurologists and neurological diagnoses can’t be trusted? Perhaps they should.

    I think he did indicate or suggest that some symptoms, such as unexplained muscle weakness, can’t just be assumed to be FND and perhaps it is this that has caused indignation (because the FND community thinks that all clinicians should now be aware that FND must be positively identified). I interpreted this as Putrino stressing the importance of all causes being considered, not just FND, because, as FND experts inform us quite often, even properly diagnosed FND can be co-morbid with other conditions, and those conditions do need to be thoroughly evaluated. Unfortunately, I think FND and functional disorders in general have previously been explained or presented to healthcare providers as being due to psychological or psychiatric problems and, as such, a means via which to cut healthcare costs by limiting investigations and treatment options. This would clearly prevent other potential or co-morbid conditions from being properly diagnosed and treated. Positively-identified FND should be able to exist as a well-defined biomedical condition without it interfering with or limiting the resourcing – investigation and treatment – of other conditions. While FND diagnosis is no longer ‘by exclusion’, that doesn’t mean that doctors should shut down the diagnostic process by not considering and testing for all conditions or etiologies that may be relevant. That’s what I thought Putrino was trying to get across, but I may be wrong.

  8. My take-away from this discussion is that FND might be a real thing that affects a small proportion of the population, and can only be properly diagnosed by well-trained experts. And at the same time large numbers of people with long Covid and other conditions are being diagnosed with FND by doctors who are not experts and have not done the proper tests. And maybe the important question isn’t “Is FND real?”, but “Is FND really as prevalent as they say?”, and “Is the FND label being used as an excuse to ignore ME and long Covid more often than it is used on people with actual legitimate FND, if such a thing exists?” (The answer to that last one is definitely yes.)

  9. That Wainwright Woman

    This has been a great discussion. It looks like the people with FND, as diagnosed by experts, have been (or are) in a predicament similar to that which people with ME (diagnosed by experts) have suffered. Both seem to endure those with agendas (related to psychologizing patients for a variety of economic and career prestige reasons) taking over the names of these conditions and moving discussions about them toward their own, non medical, objectives.

  10. Below is my response to FND Portal’s comment in this thread, which I received via email (minus the citations). I hope he will have enough spoons to be able to respond to the questions raised in this thread.

    Hello FND Portal and thank you for your email. I tried to reply via the comments button to let you know that the comments shared there by caitruthlawrence and Jocelyn Bystrom aren’t visible in the thread under David’s blog/interview with David Putrino about Long Covid and to write some of my initial comments. But there was a login glitch so I will respond further via David’s blog, when I have enough spoons. I thought your Cadenza was excellent and am optimistic that now FND is firmly on David Putrino’s radar via patient representation, thanks to you, things will change since he is the director of rehabilitation innovation.

    Your diagnostic odyssey mirrors that of many people with rare conditions and it is rare that I attend an in person rare conditions event and don’t meet someone (usually female, but not always) who has been told that if they don’t accept a conversion disorder diagnosis their primary care could be withdrawn, which can be traumatising. I am very sorry to hear that some people with FND are still being met with ‘scorn’ in medical settings and experiencing trauma as a result. That’s not OK. It’s also not OK that people (mostly women, as far as I can tell) are receiving ‘dustbin’ FND diagnoses and would be interested to know what you would consider to be a ‘dustbin’ diagnosis.

    Many years ago I read Prof Stone’s ‘bare essentials, functional symptoms in neurology’ paper and, to the best of my knowledge, he has never substantiated his ‘top tips’ stuff about people having healthy organs removed or having panic attacks misdiagnosed as asthma with statistical data. Have I missed something?

    I would also be interested to know what you would consider to be the minimum level of education/training necessary to make a FND dx.

    I’m glad you got ‘rockstar’ treatment from the FND Society. The response I got from them about one of their education webinars won them a ‘very bad patient engagement’ award so I hope they will consider learning from the rare conditions umbrella groups who do great patient engagement and are always striving to make it even better.

    More when I can (mostly from the feminist perspective) and many thanks again,

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