The Role of Oxytocin and Interoception in Functional Neurological Disorder

The primary objective is to explore interoceptive processing during a behavioural (interoceptive) tasks and its association to the oxytocin (OT) system in patients affected by a functional neurological disorder (FND), in comparison to healthy controls (HC).

Concerning interoception, as primary outcome, it is hypothesized that:

A) FND patients are less interoceptive (judged by objectively measured accuracy) compared to HC in the interoceptive tasks.

Concerning OT, as primary outcome, it is hypothesized that:

B) The OT level is correlated with interoception tasks; specifically the adaption of precision weighting

The secondary objectives are to:

• Explore the validity and reliability of different interoceptive tasks (e.g. respiratory, cardiovascular, emotional tasks)
• Explore neuronal regions associated with interoceptive processing and interoceptive accuracy in FND compared to HC
• Investigate whether FND patients have a higher interoception trait-prediction error (discrepancy between subjective and objective interoception scores) and whether this correlates with their symptom severity
• Explore the association of the breathing cycle and the voluntary initiation of mental or motor actions, and its readiness potential
• Explore peripheral biomarkers (e.g. salivary OT) in FND patients, compared to HC
• Explore the differences in (epi)genetic profile associated with the OT-system in FND compared to HC
• Investigate the association of the OT-system and traumatic childhood experience, attachment styles and sexual functioning in patients of FND compared to HC

Inclusion criteria

for Patients:

• A diagnosis of FND according to DSM-5 (Diagnostic and Statistical Manual of Mental Disorders) diagnostic criteria
• Capable of judgement
• Willing to participate in the study (by signing the informed consent form)

Inclusion criteria

for Healthy controls:

• Capable of judgement
• Willing to participate in the study (by signing the informed consent form)

Exclusion criteria

for Patients:

• Presence of comorbid disorders such as psychosis or major depression with suicidal risk
• History of actual or suspected epilepsy
• Past surgery in the brain
• Cardio-vascular disease
• Implanted Investigational Medicinal Products (e.g. cochlear implants, neurostimulators, cardiac pacemakers)
• History of alcohol or drug abuse
• For female participants: breastfeeding, pregnancy (a standard urine pregnancy test will be provided)
• <6h prior application prostaglandin
• Long QT-syndrome
• Inability to follow the procedures of the study, e.g. due to language problems

Exclusion criteria

for Healthy controls:

• History of actual or suspected epilepsy
• Past surgery in the brain
• Cardio-vascular disease
• Implanted Investigational Medicinal Products (e.g. cochlear implants, neurostimulators, cardiac pacemakers)
• History of alcohol or drug abuse
• For female participants: breastfeeding, pregnancy (a standard urine pregnancy test will be provided)
• <6h prior application prostaglandin
• Long QT-syndrome
• Inability to follow the procedures of the study, e.g. due to language problems