The Neuroconnective Endophenotype, A New Approach Toward Typing Functional Neurological Disorder: A Case-Control Study 2024 Bulbena-Vilarrasa et al

[Andy]

Abstract

Objective:
Functional neurological disorder (FND) is a core neuropsychiatric condition that includes both physical and mental symptoms. Recently, a validated clinical phenotype termed neuroconnective endophenotype (NEP), which includes several physical and psychological characteristics together with joint hypermobility (hypermobility spectrum disorders), was found at a significantly higher frequency among patients with anxiety. The purpose of the present study was to examine the presence of the NEP among patients with FND.

Methods:
The authors conducted a multicenter case-control study comprising 27 FND patients and 27 healthy control participants (matched by sex and age) ages 13 to 58 years. Eight questionnaires were administered. Proportional differences were examined with Student’s t tests, one-way analyses of variance, and chi-square tests.

Results:
Differences between FND patients and control participants were observed. FND patients had higher sensory sensitivity, increased prevalence of hypermobility features (including relevant physical signs and symptoms), greater frequency of polarized behaviors, a greater number of both psychiatric and physical comorbidities, and an increase in the characteristics and sensations typical of anxiety. Particularly striking was the presence of the hypermobility spectrum in more than 75% of FND patients compared with 15% among control participants.

Conclusions:
FND patients presented higher scores in all five dimensions included in the NEP. Thus, this phenotype, solidifying the original association between anxiety and the hypermobility spectrum, could help to identify an FND subtype when evaluating and managing FND patients, because it provides a new global view of patients’ physical and mental symptoms.

Paywall, https://psychiatryonline.org/doi/10.1176/appi.neuropsych.20240016

 

[Turtle]

Nep in Dutch means fake. FND was bad, but a NEP diagnose (first sentence) will not be embrased by Dutch patients, I think.

 

[rvallee]

Embarrassing nonsense. Always the same old nonsense. Psychosomatic medicine is an infinitely growing cancer.

 

[Hutan]

1. Find 27 patients with a diagnosis of FND, a diagnosis of anxiety and who seem to have hypermobility.
2. Find 27 healthy patients without any of these issues

3. Give both groups questionnaires covering somaticisation, anxiety and hypermobility

4. Find that the patient group ticks more boxes in the questionnaires than the healthy group

5. Announce that you have found that the so-called 'validated clinical phenotype of neuroconnective endophenotype' is prevalent in FND patients.

Particularly striking was the presence of the hypermobility spectrum in more than 75% of FND patients compared with 15% among control participants.

That's like carefully selecting oranges for the fruit bowl and then acting surprised that there are so many oranges in the fruit bowl.

 

[rvallee]

1. Find 27 patients with a diagnosis of FND, a diagnosis of anxiety and who seem to have hypermobility.
2. Find 27 healthy patients without any of these issues

3. Give both groups questionnaires covering somaticisation, anxiety and hypermobility

4. Find that the patient group ticks more boxes in the questionnaires than the healthy group

5. Announce that you have found that the so-called 'validated clinical phenotype of neuroconnective endophenotype' is prevalent in FND patients.


That's like carefully selecting oranges for the fruit bowl and then acting surprised that there are so many oranges in the fruit bowl.

Re-enactement of this process:

 

[Hutan]

Re-enactment of this process:

exactly.

 

[SNT Gatchaman]

Find 27 patients with a diagnosis of FND, a diagnosis of anxiety and who seem to have hypermobility.

One clinic specifically with patients dx with psychogenic nonepileptic pseudoseizures, the other an anxiety clinic having dx'ed them with FND (consecutively). No surprise anxiety is seen more frequently in patients partly recruited from an anxiety clinic...

Apologies if I'm missing the point: the inclusion criteria didn't mention hypermobility. Are we assuming there's a confounder that makes an FND diagnosis more likely in those thought to be hypermobile?

A. One or more symptoms of voluntary motor or sensitive alteration.
B. The clinical findings demonstrate the incompatibility between the symptoms and the recognized neurological or medical disorders.
C. The symptom or deficit is not better explained by any other medical or mental disorder.
D. The symptom or deficit causes clinically significant discomfort or deterioration in the social, occupational or other important functioning areas, or justifies a medical evaluation.

Needed to meet all 4. Note that 30% also had fibromyalgia, 41% had "CFS" and 11% had POTS - which might be suggested as "better explained by any other medical disorder."

Participants were recruited consecutively from the Hospital del Mar’s anxiety unit patient population and from among patients diagnosed with FND in the form of psychogenic nonepileptic seizures who attended the Hospital Clinic de Barcelona’s epilepsy unit or the consultation and liaison psychiatry unit. In the case of psychogenic nonepileptic seizures, the requirements of the International League of Epilepsy Commission on the Neuropsychiatric Aspects of Epilepsy were met

There were several limitations to this study, the most overt being the small sample size, although it proved to be sufficient to indicate significant differences between FND patients and healthy control participants. The small sample size primarily originated from the difficulty in enrolling patients with FND. Although data were collected and interviews were obtained from patients at two university hospitals, recruitment was difficult because the prevalence of FND cases is relatively low; however, we did achieve the necessary minimum number of cases.

Furthermore, some selection bias may have been present because individuals with more complicated socioeconomic situations may have refused to participate, leading to their potential underrepresentation. Additionally, sample size was also influenced by the enrollment of strict FND cases, excluding patients with comorbid epilepsy or other diagnosed CNS pathologies.

Control participants were healthy individuals (nonclinical subjects) recruited from the following sources: nonblood relatives of patients, volunteers from the association “Hospital del Mar Friends,” relatives of medical students, colleagues, and friends.

Odd definition of healthy, though they did not have psychiatric diagnoses. 7% had fibromyalgia, 4% had "CFS", 8% had POTS, 11% had vertigo, 4% had IBS. (Not sure how either 7% or 8% is achieved out of 27.)

 

[Sean]

1. Find 27 patients with a diagnosis of FND, a diagnosis of anxiety and who seem to have hypermobility.

2. Find 27 healthy patients without any of these issues

3. Give both groups questionnaires covering somaticisation, anxiety and hypermobility

4. Find that the patient group ticks more boxes in the questionnaires than the healthy group

5. Announce that you have found that the so-called 'validated clinical phenotype of neuroconnective endophenotype' is prevalent in FND patients.

6. Make completely unjustified assumptions and assertions about causal relationships.

7. Profit!

 

[Hutan]

One clinic specifically with patients dx with psychogenic nonepileptic pseudoseizures, the other an anxiety clinic having dx'ed them with FND (consecutively). No surprise anxiety is seen more frequently in patients partly recruited from an anxiety clinic...

Apologies if I'm missing the point: the inclusion criteria didn't mention hypermobility. Are we assuming there's a confounder that makes an FND diagnosis more likely in those thought to be hypermobile?

It was paywalled, so I couldn't see how they recruited. But, I thought the assumption that the bias towards recruitment for hypermobility would have crept in was pretty safe. Having read the excerpts, I still think that. These people devised the study thinking that hypermobility was important in FND, as part of a 'validated clinical phenotype'.

Given that the authors were playing with this idea, I imagine that they had been satisfying their curiosity by asking their patients about hypermobility, probably in the same consultation where they promoted the study. It would have been easy to provide extra encouragement to people that were thought to fit the phenotype.

They had to match the 27 participants - there's plenty of scope there to not try so hard to find a control match for someone who isn't going to support your hypothesis.

Also, importantly, if you were a patient and you were told about this study, you would be a lot more likely to participate if you believed that hypermobility was part of your problems. And you would be a lot more likely to believe that if you had heard about the study. It sounds as though they had trouble recruiting, so the selection bias may have been quite pronounced.

I'm not ruling out the possibility that some sort of hypermobility might have a connection with symptoms that are often taken to be anxiety. I just don't think this study is good enough to tell us anything reliable about that.

There were several limitations to this study, the most overt being the small sample size, although it proved to be sufficient to indicate significant differences between FND patients and healthy control participants. The small sample size primarily originated from the difficulty in enrolling patients with FND. Although data were collected and interviews were obtained from patients at two university hospitals, recruitment was difficult because the prevalence of FND cases is relatively low; however, we did achieve the necessary minimum number of cases.

How odd. And there we were, thinking that FND was 'everywhere', that it was of plague proportions in health systems.

 

[SNT Gatchaman]

Yes I almost bolded that and tagged Dave30th !

 

[Amw66]

1. Find 27 patients with a diagnosis of FND, a diagnosis of anxiety and who seem to have hypermobility.
2. Find 27 healthy patients without any of these issues

3. Give both groups questionnaires covering somaticisation, anxiety and hypermobility

4. Find that the patient group ticks more boxes in the questionnaires than the healthy group

5. Announce that you have found that the so-called 'validated clinical phenotype of neuroconnective endophenotype' is prevalent in FND patients.


That's like carefully selecting oranges for the fruit bowl and then acting surprised that there are so many oranges in the fruit bowl.

It's always worked before , why change a winning formula ?

 

[rvallee]

The small sample size primarily originated from the difficulty in enrolling patients with FND. Although data were collected and interviews were obtained from patients at two university hospitals, recruitment was difficult because the prevalence of FND cases is relatively low;

But the 'experts' keep saying that it's one of the most common disorders seen in health care, possibly the most common problem. That seems to conflict a bit. Just a tiny bit. It's both one of the most common disorders and also rare. You can be anything if you want to.

Also, what I was thinking that this comes from an anxiety clinic and they hand out 'anxiety' questionnaires (which convenient happen to ask overlapping questions):

See, you know that any cat in that box is an asshole because it says so on the box.

- Person who made the box​