Open Letter to Davids Tuller and Putrino

This post was originally posted as a comment on virology.ws by yours truly. It was addressed to David Tuller, who uploaded a video of himself and Long Covid researcher David Putrino discussing FND (and my views specifically) at length. Here is my response in full, which has been lightly edited for clarity.

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Hello David, I am 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 various 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 (which among other claims stated “a good-faith argument linking FND to Long COVID is no longer possible”) 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 that it has a specific physiological basis that can be differentiated from other disorders. I was concerned that his highlighting of viral persistence as the sole putative 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 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 the clinical 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, 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 the apparent reasonableness of Putrino’s argument, which sounds ok on the surface – that we need not think about potential FND in LC because it’s diagnostically fuzzy, and anyway doesn’t the virus explain all the symptoms 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. Putrino apparently thinks his neuroscientific background is sufficient to bypass that, but it’s not. It’s a central aspect of respecting disability communities, which had he shown it would have demonstrated 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 (these from a thread posted by Dr. David Perez on May 5, 2023)

https://pn.bmj.com/content/13/6/396

https://n.neurology.org/content/94/24/1093

https://movementdisorders.onlinelibrary.wiley.com/doi/epdf/10.1002/mdc3.12966

https://jnnp.bmj.com/content/85/2/180

https://www.bmj.com/content/371/bmj.m3745

https://jamanetwork.com/journals/jamaneurology/article-abstract/2682656