Hedonicity in functional motor disorders: a chemosensory study assessing taste, 2020, Cecchini

Hard to go past a paper with a title like that.

But I haven't got to the taste bits yet, still stuck on the suggestions of the first paragraph.

The paper starts off with a description of all the emotional processing inadequacies of people with functional motor disorders

• often associated with psychiatric comorbidity, e.g., personality disorders and severe distress, disability, and social isolation
• patients have been reported to show altered sensory processing (Morgante et al. 2018), ..., associated with abnormal identification of emotions and changes in emotion regulation strategies
• Impairment of emotional processing was documented in patients with non-epileptic seizures (Nováková et al. 2015), and reduced positive emotional behavior to pleasant, neutral, and unpleasant pictures was reported in these patients
• Indeed, alterations in neural circuits mediating emotional processing and perceptual awareness (Perez et al. 2015) and abnormal activity in the insula (Lehn et al. 2016) were reported in FMDs.
• Patients with FMDs often have anxiety, depression, alexithymia, and/or affect dysfunction
• These converging pieces of evidence suggest that abnormal interaction between sensory processing and emotional valence might represent a trait of FMDs.

So, the foundation of the hypothesis of this study is that 'abnormal sensory and emotional processing'.

The researchers assessed the 20 people with functional motor disorders (e.g. gait disturbances, leg tremors and weakness) and 24 controls for anxiety, depression and Alexithymia

Of course these FMD people with their wide ranging emotional processing issues should look quite different to the controls.

This is what they found: (you'd think the results might be worth a table, but this is all the data there is)

Anxiety
So the average HARS score was 9.1 and the paper tells us that 8 to 14 is mild anxiety - so, at the lower end of mild anxiety, nearly normal. I wouldn't be surprised if most cohorts of people with significant chronic illness would look similar.

Depression
The average depression score was 10.7 and the paper tells us that 8 to 17 is mild depressive symptoms. So again, at the lower end of mild depression, nearly normal. Pretty unremarkable for people whose bodies are chronically not doing what is expected of them I would have thought. Also, this measure is assessed by a clinician with an interview-based rating scale, so plenty of room for bias.

Alexithymia - the capacity to identify and describe feelings
The average TAS-score was 48.9 (plus or minus 12). The paper doesn't actually tell us what the normal values for this instrument are, or tell us what the controls scored. But, I remember this paper that reported an average TAS value for a normal Japanese cohort of 48. 48 (plus or minus 9)!
The longitudinal effects of seated isometric yoga on blood biomarkers, autonomic functions, & psychological parameters of [PwCFS], 2019, Oka et al

So, this cohort of people with a range of 'functional motor disorders' looked perfectly normal for a group of people with chronic illness; with alexithymia scores that are perfectly normal for 'normal' people.


Now, this is quite a finding - all those previous studies have found that people with FMD have emotional processing issues and this study doesn't. Surely this is worth some exclamation, or even just a comment? But, no. The paper says nowhere (I think) that these people had normal alexithymia. There's no discussion of how that might affect their underlying hypothesis of sensory and emotional processing being faulty in FMD.

And - they found no relationship between taste perception and anxiety, depression and alexithymia.

So, with the underlying hypothesis of linked abnormal emotional and sensory processing being a bit shot to pieces, the idea of checking if people with FMD have normal taste perception looks a bit random. But whatever, it sounds like a fun and cheap experiment.

The statements in the discussion reach way beyond what they actually found.

Yeah, so I didn't even get to the hedonic bit.