Association between brain metabolism and clinical course of motor functional neurological disorders, 2022, Conejero et al

Abstract
Features of resting brain metabolism in motor functional neurological disorder are poorly characterized. This study aimed to investigate the alterations of resting brain metabolism in a cohort of patients experiencing a first episode of motor functional neurological disorder with recent symptom onset, and their association with persistent disability after 3 months.

Patients eligible for inclusion were diagnosed with first episode of motor functional neurological disorder, were free from bipolar disorder, substance use disorder, schizophrenia, psychogenic non-epileptic seizure or any chronic or acute organic neurological disorder. Exclusion criteria included current suicidal ideation, antipsychotic intake and previous history of functional neurological disorder. Nineteen patients were recruited in Psychiatry and Neurology departments from 2 hospitals. Resting brain metabolism measured with 18F-fluorodeoxyglucose positron emission computed tomography at baseline and 3 months was compared to 23 controls without neurological impairment. Disability was scored using Expanded Disability Status Scale and National Institutes of Health Stroke Scale score at baseline and 3 months. Correlations were calculated with Spearman correlation coefficient.

Hypometabolism was found at baseline in bilateral frontal regions in patients versus controls, disappearing by 3 months. The patients with Expanded Disability Status Scale score improvement showed greater resting state activity of prefrontal dorsolateral cortex, right orbito-frontal cortex and bilateral frontopolar metabolism at 3 months versus other patients. The resting state metabolism of the right subgenual anterior cingular cortex at baseline was negatively correlated with improvement of motor disability (measured with Expanded Disability Status Scale) between inclusion and 3 months (r=-0.75, p = 0.0018) and with change in motor symptoms assessed with the National Institutes of Health Stroke Scale (r=-0.81, p= 0.0005). The resting state metabolism of the left subgenual anterior cingular cortex at baseline was negatively correlated with improvement in Expanded Disability Status Scale and National Institutes of Health Stroke Scale scores between inclusion and 3 months (r= -0.65, p = 0.01 and r= -0.75, p = 0.0021, respectively). The negative association between the brain metabolism of the right subgenual anterior cingular cortex at baseline and change in National Institutes of Health Stroke Scale score remained significant (r=-0.81, p= 0.0414) after correction for multiple comparisons.

Our findings suggest the existence of metabolic “state markers” associated with motor disability and that brain markers are associated with motor recovery in functional neurological disorder patients.

Paywall, https://academic.oup.com/brain/advance-article-abstract/doi/10.1093/brain/awac146/6571651

 

It has been said before but how can it be a functional disorder if they have found the brain results of patients differ from healthy controls?

 

[sorry if this makes no sense, I am currently struggling linking my thoughts to useful wording]

I have not bothered to look at the actual article, but there is always the problem of distinguishing between authors who use ‘functional’ in a purely mechanistic sense and those that use it as a synonym for ‘psychosomatic’.

Also it theoretically possible that a ‘software’ issue shows up in observable brain function regardless of any ‘psychogenic’ issues, and it could be theoretically possible or even probable that particular thoughts give rise to potentially observable neuro electrical or neuro chemical activity. However, the language and thinking of researchers in the field of functional conditions is so messy that it is a struggle to pin down what they might mean, especially given the limitations of our current understanding of brain function.

Further it does seem that advocates of functional conditions are belief driven rather than data driven, and even if they have got anywhere near demonstrating associations, invariably inferences of causation go well beyond the available evidence which equally could demonstrate causality in the opposite direction.

 

This! Maybe that's considered a feature, not a bug

 

I see what you are saying but I think you give them too much credit. We have to guess what they really mean so we always have to wonder if they can be as bad as they seem this time but I have never seen it yet

They specifically mention FND so this is not a confusion of the use of functional. It was Stone and his FND cronies who first used the software versus hardware comparison to make FND palatable to patients so there is no need to spend energy trying to understand if it could be a biological phenomenon.

The problem is that the only evidence put forward for functional syndromes is that they do not have a biological basis so must be psychogenic. They have twisted this by saying they have found biological processes that are signs of psychogenic disease but this is not valid because they may have found the biological components of new types of disease but they have still not shown any proof they are psychogenic except that they are being found in people they have decided have psychogenic disease because they do not have biological deficits.

The best proof of psychological problems causing disease would be if they were treated by psychological means but there are no positive results.

It is to the credit of people in the ME community that they are open to examining scientific theories they disagree with to see if there is any merit to them.