Author: Akihiro Koreki, Sarah N Garfkinel, Marco Mula, Niruj Agrawal, Sarah Cope, Talia Eilon, Cassandra Gould Van Praag, Hugo D Critchley, Mark Edwards, Mahinda Yogarajah
1 Neurosciences Research Centre, St George's University of London, London, UK.
2 Department of Neuropsychiatry, National Hospital Organization Shimofusa Psychiatric Medical Center, Chiba, Japan.
3 Brighton and Sussex Medical School and The Sackler Centre for Consciousness Science, University of Sussex, Sussex, UK.
4 Atkinson Morley Regional Neuroscience Centre, St George's Hospital, London, UK.
5 Department of Neuropsychiatry, South West London and St George's Mental Health Trust, London, UK.
6 Department of Psychiatry, University of Oxford, Oxford, UK.
Date published: 2020 Jun 5
Other: Word Count: 284
PMID: 32501547 DOI: 10.1111/epi.16532
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.
Keywords: dissociation; dissociative seizures; functional seizures; interoception; nonepileptic attack disorder; psychogenic nonepileptic seizures.
© 2020 The Authors. Epilepsia published by Wiley Periodicals LLC on behalf of International League Against Epilepsy.