NCT06084325

The Role of Oxytocin and Interoception in Functional Neurological Disorder

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 110 (actual)
• Sponsor: University of Fribourg · Academic / Other
• Sex: All
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

The main goal of this project is to better understand the role of oxytocin and Interoception in FND. More specifically oxytocin's association with precision weighing, prediction errors and priors in the interoceptive domains will be investigated. To this end, several methods will be employed: analysis of interoceptive accuracy and sensibility (interoceptive tasks and questionnaires), biomarkers of oxytocin (peripheral, endogenous oxytocin), genetic oxytocin markers (such as allele-frequency in the oxytonergic receptor gene), epigenetics (methylation rates of genes related to oxytocin), neuroactivity (EEG).

Detailed description

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

Conditions

• Functional Neurological Disorder

Interventions

Type	Name	Description
DEVICE	Respiration resistance sensitivity task (RRST)	The RRST measures interoception on the domain of the breath and thus allows its (non-invasive) manipulation. The RRST apparatus includes a step motor that moves a wedge piece back and forth to change the obstruction level in the breathing circuit. This fully automated apparatus will change the breathing obstruction level via a computer-controlled algorithm. The patient breath by the month though this device.
BEHAVIORAL	Heartbeat Tracking (HBT)	The HBT measures interoception on the domain of the cardiovascular system, by assessing how accurate participants perceive their own heartbeat. After each time window participants will be asked how many heartbeats they counted, which will be compared to the actual heartbeat measured via electrocardiography (ECG).
DEVICE	Heartbeat evoked potential (HEP)	The HEP is computed by averaging EEG signals time-locked to specific peaks of simultaneously measured ECG signals. Therefore both an ECG and an EEG will be set up for the participants. The task during the HEP is to simply focus on interoceptive tones (the own heartbeat) with a control condition of focusing on exteroceptive tones (sounds played). A further condition of HEP measurement is the cardio-audio synchronization. Hereby, participants will be instructed to passively listen to sounds presented to them via in-ear phones while further fixating the cross.
DEVICE	Libet task	Additionally we also link the interoceptive domain of the breath to a well-known and established agency task measuring conscious intention. Participants will do two versions of the Libet taks while simultaneously recording their EEG and breathing signals with a respiratory belt.

Timeline

• Start date: 2023-10-05
• Primary completion: 2025-01-24
• Completion: 2025-01-24
• First posted: 2023-10-16
• Last updated: 2025-03-27

Locations

2 sites across 1 country: Switzerland