The complex syndrome of functional neurological disorder, 2022, Edwards et al

[Sly Saint]

Abstract
Background
Patients with functional neurological disorders (FND) often present with multiple motor, sensory, psychological and cognitive symptoms. In order to explore the relationship between these common symptoms, we performed a detailed clinical assessment of motor, non-motor symptoms, health-related quality of life (HRQoL) and disability in a large cohort of patients with motor FND. To understand the clinical heterogeneity, cluster analysis was used to search for subgroups within the cohort.

Methods
One hundred fifty-two patients with a clinically established diagnosis of motor FND were assessed for motor symptom severity using the Simplified Functional Movement Disorder Rating Scale (S-FMDRS), the number of different motor phenotypes (i.e. tremor, dystonia, gait disorder, myoclonus, and weakness), gait severity and postural instability. All patients then evaluated each motor symptom type severity on a Likert scale and completed questionnaires for depression, anxiety, pain, fatigue, cognitive complaints and HRQoL.

Results
Significant correlations were found among the self-reported and all objective motor symptoms severity measures. All self-reported measures including HRQoL correlated strongly with each other. S-FMDRS weakly correlated with HRQoL. Hierarchical cluster analysis supplemented with gap statistics revealed a homogenous patient sample which could not be separated into subgroups.

Conclusions
We interpret the lack of evidence of clusters along with a high degree of correlation between all self-reported and objective measures of motor or non-motor symptoms and HRQoL within current neurobiological models as evidence to support a unified pathophysiology of ‘functional’ symptoms. Our results support the unification of functional and somatic syndromes in classification schemes and for future mechanistic and therapeutic research.

https://www.cambridge.org/core/jour...cal-disorder/928FA00043CEA47612B9F0EACB2C4BB8

 

[Snow Leopard]

Alternatively, the lack of "clustering" could be due to the questionnaires themselves lacking in specificity.

 

[Mithriel]

A few things spring to mind. Motor FND may be all one disease or it could be that symptoms (including depression and anxiety) are very similar across all motor disabilities. They did not have a control group of MS patients or Parkinson patients with a similar level of disability.

Significant correlations were found among the self-reported and all objective motor symptoms severity measures.

indicates that patients had a very good grasp of their actual limitations, they were not exaggerating and did not have any false perceptions.

Another thing is they do not address that FND does not just include motor disorders. How do people with IBS or seizures or interstitial cystitis fit?

We interpret the lack of evidence of clusters along with a high degree of correlation between all self-reported and objective measures of motor or non-motor symptoms and HRQoL within current neurobiological models as evidence to support a unified pathophysiology of ‘functional’ symptoms.

So they take a subgroup with similar symptoms say they all have similar symptoms and use that to say ALL functional disorders are similar with the implication that it is correct to say it is a new name for hysteria.

 

[alktipping]

Another seven people who assume an unproven hypothesis is a n accepted fact . personally i would not allow them anywhere near patients .

 

[Snowdrop]

What I am starting to find interesting is that I think I'm starting to see a new pattern in papers. Someone can enlighten me if they have better knowledge. It looks to me like the usual British writers of suspect papers are increasingly teaming up with researchers from outside UK. There was always some of that going on but they seem to be looking increasingly farther afield.

I'm just hoping it means funding is being more carefully scrutinised as to it's benefit. Writing a new paper on the same subject with a huge archive with remarkably similar conclusions should never have been considered money well spent.

 

[Arnie Pye]

One hundred fifty-two patients with a clinically established diagnosis of motor FND were assessed for motor symptom severity using the Simplified Functional Movement Disorder Rating Scale (S-FMDRS), the number of different motor phenotypes (i.e. tremor, dystonia, gait disorder, myoclonus, and weakness), gait severity and postural instability.

I'm glad I was never diagnosed with FND when I had serious gait problems. Luckily for me my real problem was discovered by accident as a result of having a CT scan for a possible stroke (I hadn't had a stroke.). It turned out I had NPH - Normal Pressure Hydrocephalus. Without the accident of the CT scan I would probably have remained either ignored or been diagnosed with a mental illness.