Positive signs for FND: Looking for Criticism

Hello. I am new to here and have an interest in critiques of Functional Neurological Disorder. I knew that three "positive" rule-in signs were tremor entrapments, Hoover's sign, and psychogenic seizures, but I also found a table that listed positive signs you will see in the table linked below. I would like to know your thoughts on these and how rigorous they are. I have had symptoms of CFS but ended up developing a rare neurological condition called Mal de Debarquement syndrome. It has come to my attention that there are some doctors diagnosing people with this with FND (especially in the UK, but some in the US). FND is potentially a huge threat to data loss in rare patient populations. I know David Tuller has criticized statistical methods used by these scientists but I'd also love to hear any critique people may have from a neuroscientific standpoint, if any. I am glad I found this forum.

Some of these listed are:
"Intermittent gait abnormalities, improving with distraction: non-economic postures on walking, exaggerated pelvic swaying, huffing and puffing sign, give-away weakness of the legs; non-anatomic hypoesthesia. movements, impaired balance upon examination with positive shoulder touch test, huffing and puffing sing."

Table 1. Positive signs of functional neurological disorders ...

Journal of Neurology, Neurosurgery and Psychiatry
https://jnnp.bmj.com › inline-supplementary-material-1

 

Hi @AR561. I am a professor of medicine trained in neuroscience and clinical neurology but not a neurologist. I accept that, like all neurological signs, these signs are useful in coming to a diagnosis. No single sign is 'rigorous' in neurology. The diagnosis always depends on the entire picture of symptoms and signs and the consistency of that picture.

Signs such as these indicate that symptoms are likely to be in part due to higher-level cortico-thalamic function not associated with any local structural lesion. That does not mean they are due to 'bad thinking' but it means that they are likely to arise in the parts of the brain involved in generation and use of thoughts. I don't like the term FND because it is deliberately ambiguous and has a connotation of 'psychosomatic' when nobody knows what that means.

Having seen these signs I don't think the problem is that neurologists are wrong to deduce that they arise from parts of the brain closely involved in thinking. I think the problem is that those who talk of FND have no understanding of psychology or how to apply it to such problems. Or perhaps to say that psychology in its present form is a lot of non-scientific nonsense.

So I wouldn't bother about the validity of these signs much. It will depend on the skill of the physician. The problem lies much deeper with the concept. There is also a problem in FND enthusiasts recommending that non-specialists use these signs but that is not a problem with the sign, rather a problem with the complexity of acquiring good neurological skills, which tends to take at least 5 years hard practice.

 

I’ll be responding with a few comments. I apologize if I’m all over the place. Insomnia and brain fog.

Thank you for your response. I wanted to add that one of the biggest issues with FND is despite the “positive” signs they consider to be rule-ins, this entire category of psychosomatic medicine depends on pro-innovation bias (excessive optimism toward medical technology’s current capacity to answer all of the relevant questions).

I’m not sure if you’ve heard of it but there’s a field called “functional neurology” or “chiropractic neurology” that works outside of conventional medicine and some of them are very advanced in the courses they have to take as well as the evaluations they do. They take extra courses in neurology based on established and growing/newer science. It’s interesting how their approach to the brain/sensory integration does not consider “functional” to mean “psychiatric.” Dr. Nathan Keiser is a FN I follow on social media who has some great videos you may be interested in. Another mention is MSK Neurology’s page, while although anti-chiropractic, discusses relevant biomechanics that cause a wide range of symptoms—it is very in depth, technical, and relevant to this field because I think what he’s shown would potentially demolish many so called FND patients (which are likely causing a loss of data through this diagnosis).

Moreover, a lot of radiological reports miss certain things, which the author has seen repeatedly. The evaluations by many doctors don’t always include everything of relevance in the physical examination (also detailed on his website and videos) or consideration of what the symptoms signify. For instance, it was thought intracranial hypertension without papilledema was rare; this is based on the assumption it must present in a more extreme way clinically when that is not always the case.

In CFS they’re finding the ICP is on the higher end but not “high enough” by the usual diagnosis of IIH, yet still present with symptom overlap and they’re looking into successful treatments for this (Higgins et. al, 2023). The author of MSK neurology is also finding many patients with IIHWOP/craniovascular issues in the case of many vestibular/neuro problems. He’s outlined the complex anatomical connections between it, tinnitus, tics, autonomic conditionsc etc. I’ll link to his page so you can see it. It’s outstanding.

Although I don’t understand it all (medical terminology) I see how important it is because the ENTIRE conventional field of functional neurology seems to lack even one expert on biomechanics who has enough experience to ask all these pertinent questions. I myself have some IIHWOP symptoms and have for many years. I have MdDS and just found out a major MdDS researcher is finding vascular compression in the neck of patients ONLY if actually looked for through CT venogram and doppler ultrasound in two different positions. They’re also finding TOS in these patients and higher ICP. This is evolving and in the research phase but it’s interesting I had already suspected this was a common issue after several years of emailing a retired doctor who is also a researcher that has IIHWOP (so do her children). It’s likely way more common than thought but unfortunately medicine will stay behind until the research is fully developed. I also have a smaller cerebellar tonsillar herniation, which radiologists initially missed. I fortunately got a scientist friend to do a favor (years ago) by helping me get a second opinion and a radiological expert saw the herniation and gave me the image with the measurement. I’ve got the image proof. He didn’t understand why they failed to measure or report it but at the same time it’s not uncommon for radiologists to miss certain things and count it as “unremarkable”. This type of imaging also doesn’t count the effects of gravity due to being supine. This too can potentially be a secondary issue related to raised ICP. I wanted to get the vascular neck imaging relevant to MdDS/my symptoms but it would be a fortune out of network because insurance limits rare disorder patients such as myself. Getting a spinal tap would also be risky, as it has been reported in some cases to pull a herniation further down. Still, there are signs and clues that hint to potential ICP problems.

Then there is the issue in sleep medicine of UARS. I had sleep apnea as a child and got surgery. I still however have chronic insomnia. I got a sleep study and they told me "Well, no sleep apnea” and wanted to give me medicine for restless legs that I get on occasion, when this is not my main issue. I have insomnia with or without RLS. I sent the full report to a retired doctor/sleep medicine researcher I know (who also takes interest in biomechanical problems in certain patient-populations). She immediately saw red flags: too many arousals per hour and double of it being in REM, which signals respiratory related arousals (these can occur before airway collapse, thus not causing total apnea). I also had 54% sleep efficiency and that was on a good night (subjectively). She has seen many people reported normal at some labs then other labs find the abnormalities. I am sorry to go into too much but I want anyone reading this to be aware of the shortfalls of conventional medicine and why the FND diagnosis could be slapped on people who have conditions being missed. I am beyond, and I mean beyond, frustrated.

Here are the important links I implore anyone to read:


https://mskneurology.com/myalgic-encephalomyelitis-me-biomechanical/

https://mskneurology.com/atlas-joint-instability-causes-consequences-solutions/

The opinions expressed in my comments are my own and anyone interested in the author of MSK Neurology’s page can find his direct statements/commentary on his FB and website.

 

There’s also this article that mentions somatoform conditions and the limitations to technology:

The Involvement of Secondary Neuronal Damage in the Development of Neuropsychiatric Disorders Following Brain Insults

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949352/


“However, 40% of neuropsychiatric signs and symptoms were found to be commonly shared by traumatic, infectious, toxic, oncogenic, and degenerative brain insults, suggesting that the same or similar brain regions/structures can be possibly affected by different acute and chronic brain insults.”


“A neuropsychiatric disorder should have its morphological alter-ations in the brain. Any brain insult can certainly cause histo-morphological, biochemical, or molecular biological alterations in some parts of the brain, such as the limbic system, basal ganglia system, the brainstem, the basal forebrain, the cerebellum, and the cerebral cortex. Unfortunately, these alterations at the cellular and molecular level are usually not easy to detect by using traditional diagnostic imaging techniques (e.g., ultrasound, X-rays, CT, and MRI), because tiny morphological changes (such as neuronal cell death or loss) in deep brain structures (such as the limbic system and basal ganglia system) can be often covered by other normal neural tissue layers of the brain. Much of the neuronal damage in deep brain structures can be seen only under a microscope after death (13).”

 

Some of the FND articles I saw also mention they don’t know the loop of causality: do mental symptoms come first or after the patient’s perception of physical symptoms? They also assume that in practice neurologists will realize that their version of FND can exist alongside other neurological conditions. The issue is the FND diagnosis itself will bias the doctor (and has in many cases reported by people) into thinking all of their neuro symptoms are relevant to FND when the usual tests come up missing. With rare conditions being as common as diabetes (collectively) designating patients to Somatic Symptom Disorder or FND is reckless. There are already people with MdDS unfortunately being misdiagnosed with FND. We don’t even know the true misdiagnosis rate even though Stone and the FND cronies will say it’s “low.” How do we know it’s low when not all cases are reported? We truly have no clue how many people out there currently sit with a faulty diagnosis because of lack of understanding of the very thing MSK Neurology outlines.

And with psychiatric conditions being found potentially linked to the immune system or other changes only discoverable through continued efforts in research science, the field of FND is just too narrow and assuming. Sensory integration is a huge part of human wellness and the devastating impacts of sensory mismatch are not “psychiatric subconscious processes” but complex physical ones generated by information from all of our senses (eyes, proprioceptive, central and peripheral vestibular). This can lead to autonomic disturbance/vestibular problems. I had a RightEye test (currently can be found on pubmed articles) and there were issues in my eye tracking. This technology measures eye movements neurologists can’t. I for years, like many, had postural distortions (head tilt to the left, mild scoliosis that developed as a child and was reported in imaging) that created issues in sensory processing. I can’t outline all of the scientific detail but there are researchers and clinicians who are more advanced in this area. My main point is simply that with all of the interconnectedness and bidirectional pathways going on, FND being a “psychiatric” issue is highly questionable and the burden of proof rests on them.

Important note: adding in, MSK Neurology does not endorse or recommend chiropractic at all, including chiropractic neurology. I was simply listing both as they both have mentioned issues in biomechanics/the autonomic system that are routinely ignored by regular physicians. I simply think the author of MSK Neurology is doing great service in biomechanics and relevant issues that should interest anyone in the ME/CFS field. Any other opinion stated is that strictly of my own. Anyone interested in his work can read his own articles or follow his pages where he discusses biomechanical issues/therapies more in-depth.

I’m 27 now but my scoliosis was found when I was a child. One must keep in mind that mild scoliosis and forward head posture are not uncommon. Here are some interesting articles on this and sensory issues in psychiatric disorders:

Deficits of Sensory Integration and Balance as Well as Scoliotic Changes in Young Schoolgirls
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9919114/

Forward Head Posture Symptoms And Complications


https://caringmedical.com/prolotherapy-news/forward-head-posture/


Vestibular insights into cognition and psychiatry
https://www.sciencedirect.com/science/article/pii/S0006899313012134#:~:text=Existing research describes clear links,symptoms of psychosis and mania.

The Importance of Sensory Processing in Mental Health: A Proposed Addition to the Research Domain Criteria (RDoC) and Suggestions for RDoC 2.0

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6370662/

 

Hi, @AR561,

Yes, I have got familiar with the 'chiropractic medicine' side of things since being interested in ME/CFS and have come across Keiser and MSK Neurology. This is all just fake medicine in my view. The methods they sell have no scientific basis and no evidence basis in clinical practice as far as I know. The peer review in journals is so poor these days you may see publications from groups of this sort that claim to be scientific.

To my mind, if we do not understand something in medicine it is best to admit that rather than claim this theory or that. The thing that intrigues me most is that although the psychosomatic people and the pseudo-phyiological people seem to be in opposite camps they often mix and match both sides. (That means you can have a 'biopsychosocial' theory that explains anything.)

 

We can agree to disagree. His entire page, posts, and discussions (Kjetil's) do have compelling evidence/rationale and it's also a field that's being expanded on: not finished as science is a method/process. Proof gaming doesn't work when large amounts of time, grant funding, and effort are involved. Like I said, I also know people who have IIHWOP and only got diagnosed after spinal taps because the doctor finally realized the symptom overlaps do not only occur with papilledema, something many doctors considered to be "nearly impossible" and therefore do not test for/treat. There are hundreds upon hundreds or more cases similar to this being posted for people who fit these symptoms yet it is never explored or evaluated. So, we don't know the true number. I will continue to listen to the lived experiences of patients and clinicians in this area as well as the observations from these clinicians and scientists who are looking into it. None of it is "finished" but to dismiss it outright is not helpful to patients in these communities who are being branded as having FND or "nothing really physiological" when there are major red flags showing otherwise. The problem is too many "medical technicians" do not think outside of the box or ask all of the right questions. Plus, they're not the only people in this field, just some I thought to mention. There is skin in the game. Not all of them agree on everything anyway but that isn't to say their contributions aren't important or can't be further elucidated in future research. Dismissing everything in one felled swoop is just... Not helpful. There are extensive writings and examinations detailed on MSK Neurology's FB page that would require many hours to dive into and read all of, including detailed classes he offers that involve objective biomechanics and spine imaging with its clinical correlation (with citations). Not every single radiological report or presentation/case he has is even published but he has left a lot open so I am interested in seeing a debate between him and those who dismiss it all as if his observations and patient's experiences really are just moot. Not to mention he does go over rationale of treatment, results, and limitations in the field of physical therapy/science. I have zero doubt him and many others would be fine with getting their work published further and wider if it meant more patients get help/propel the science forward. And given I have spoken to some professionals who have decades of personal experience with patients or research (and the many people they know doing the same) I realize this is absolutely not an area to just outright deny as pseudoscience.

Also, once again adding in that MSK Neurology does not endorse or recommend chiropractic or chiropractic neurology, simply that I was stating some of the work in these realms highlight biomechanical issues routinely ignored by many doctors (vestibular, ICP, and autonomic).

"Science begins its work based upon a principle called necessity, not upon proof. Science then establishes proof, if such can be had. Popper critical rationality as it turns out, involves more than irrefutable proof, contrary to what gaming social skeptics might contend. Proof Gaming is a method of tendering an affectation of sciencey methodology, yet still effectively obfuscating research and enforcing acceptable thought."

https://theethicalskeptic.com/2017/02/28/deskeption-proof-gaming/