Trait and state interoceptive abnormalities are associated with dissociation and seizure frequency in patients with functional seizures, 2020, Koreki

[Andy]

Objective

Dissociative traits represent a disturbance in selfhood that may predispose to, and trigger, functional seizures (FSs). The predictive representation and control of the internal physiological state of the body (interoception) are proposed to underpin the integrity of the sense of self (“minimal selfhood”). Therefore, discrepancies between objective and subjective aspects of interoception may relate to symptom expression in patients with FSs. Here, we tested whether individual differences in trait measures of interoception relate to dissociative symptoms, and whether state interoceptive deficits predict FS occurrence.

Methods
Forty‐one participants with FSs and 30 controls completed questionnaire ratings of dissociation, and measures of (1) interoceptive accuracy (IA)—objective performance on heartbeat detection tasks; (2) trait interoceptive sensibility—subjective sensitivity to internal sensations (using the Porges Body Perception Questionnaire); and (3) state interoceptive sensibility—subjective trial‐by‐trial measures of confidence in heartbeat detection. Interoceptive trait prediction error (ITPE) was calculated from the discrepancy between IA and trait sensibility, and interoceptive state prediction error (ISPE) from the discrepancy between IA and state sensibility.

Results
Patients with FSs had significantly lower IA and greater trait interoceptive sensibility than healthy controls. ITPE was the strongest predictor of dissociation after controlling for trait anxiety and depression in a regression model. ISPE correlated significantly with FS frequency after controlling for state anxiety.

Significance
Patients with FSs have disturbances in interoceptive processing that predict both dissociative traits reflecting the disrupted integrity of self‐representation, and the expression of FSs. These findings provide insight into the pathophysiology of functional neurological disorder, and could lead to novel diagnostic and therapeutic approaches.

Open access, https://onlinelibrary.wiley.com/doi/full/10.1111/epi.16532

 

[Woolie]

whoa, my bullshitometer went right off the scale!

Dissociation is thought to be an important factor in the predisposition to and generation of the disorder. Dissociation represents a loss of, or a reduction in, the integration of psychological processes and underlying functional neural mechanisms normally amenable to volitional control. In Pierre Janet's 19th century account of hysteria,7 FSs are conceptualized as intrusive sensorimotor flashbacks with psychological fragmentation, when mental functions including memories of traumatic events are separated or “dissociated” from consciousness. Here, FSs are considered a defensive process to manage otherwise overwhelming feelings, experiences, or stress.7 In this context, FSs represent a form of “somatoform” dissociation where dissociative symptoms phenomenologically involve the body8 and reflect the disintegration of neural systems normally amenable to deliberate control.9 This can be measured using the Somatoform Dissociation Questionnaire (SDQ‐20).10 A variant of this account describes FSs as altered states of consciousness similar to panic attacks, but in which the subjective fear component is dissociated from awareness. Here, dissociative symptoms phenomenologically involve psychological variables,8 and the dissociation reflects a state of “detachment” encompassing depersonalization.11 This form of “psychological” dissociation can be measured using the depersonalization subscale of the Multiscale Dissociation Inventory (MDI).12

 

[Woolie]

They go on to offer what collapses down to a similar view embedded in modern terminology ("predictive coding" is all the rage in cognitive neuroscience now!)

this model maintains that disorders of presence or body ownership, such as dissociation, result from pathologically imprecise interoceptive predictive signals... this model has been supported by studies demonstrating interoceptive deficits in patients with primary dissociative disorders.16

The reference "16" they cite actually endorses the idea of dissociative identity disorder, which most psychologists just scoff at!

Anyway, what they did was to ask their patients to track their heartbeat (count the number of beats they thought their heart made over a short period), and another task where they had to say whether their heart beat was in synch or out of synch with a series of tones. Only the first of these measures differed between patients and a group of healthy controls.

Then they gave them various scales that purport to measure various constructs that may or may not exist (I'm inclined to think they don't, so was not much interested in what these showed, and not much surprised to find that the patients reported more distress and anxiety than happy healthy folks).

Two huge problems imo.

1. What were the patients' and controls' actual heart rates? My guess is you're likely to be better at tracking your heart rate if its slow and regular, than if its fast and racing.

2. (the huge elephant in the room) They compared a chronically ill group to a bunch of healthy people, so there's no way of knowing whether their patients' abnormal scores on some of the tests are something that's common in chronic illness, irrespective of cause, or whether they genuinely point at some sort of "psychological" causation. Its not unreasonable to predict that people with with various sorts of illnesses - especially illnesses with a highly variable course - might be less good at making these kinds of estimations.

A reasonable control group might have been people with epileptic seizures, which has similarities in terms of patient experience (although when epilepsy is properly managed, the seizures are usually nowhere near as frequent), but not believed to be "psychological" in origin.

They would of course say that there's no need to look at another control group, because we already "know" the problem is psychological, that's "well established". It isn't at all, as Ward and Wilshire showed in their review and metanalysis, but the game of medical chinese whispers has a power all of its own.

 

[rvallee]

whoa, my bullshitometer went right off the scale!

My model goes: woo woo woo woo!

Arbitrary benchmarks be arbitrary. Reminds me of psychics who have this gizmo where if this book jumps up it means a spirit is talking to them. Can we make this a different book? It's all the same anyway. No, of course, must be this book, you know, the one connected to a thing that activates with a buzzer.