The Role of Oxytocin and Interoception in Functional Neurological Disorder

Recruiting

• Conditions: Functional Neurological Disorder
• Interventions: Device: Respiration resistance sensitivity task (RRST); Behavioral: Heartbeat Tracking (HBT); Device: Heartbeat evoked potential (HEP); Device: Libet task

• Registration Number: NCT06084325
• Lead Sponsor: University of Fribourg

Brief 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

Study Timeline

• Study First Submitted: 2023-09-20
• Status Verified: 2023-10
• Study Start: 2023-10-05
• Study First Submitted QC: 2023-10-09
• Last Update Submitted: 2023-10-09
• Study First Posted: 2023-10-16
• Last Update Posted: 2023-10-16
• Primary Completion: 2024-12
• Study Completion: 2026-12

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

Not provided

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Exclusion Criteria

Not provided

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Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
FND Patients	Respiration resistance sensitivity task (RRST)	Group of patients with functional neurological disorders
FND Patients	Libet task	Group of patients with functional neurological disorders
Healthy control	Respiration resistance sensitivity task (RRST)	Age matched group control of healthy participant
FND Patients	Heartbeat evoked potential (HEP)	Group of patients with functional neurological disorders
FND Patients	Heartbeat Tracking (HBT)	Group of patients with functional neurological disorders
Healthy control	Heartbeat Tracking (HBT)	Age matched group control of healthy participant
Healthy control	Libet task	Age matched group control of healthy participant
Healthy control	Heartbeat evoked potential (HEP)	Age matched group control of healthy participant

Primary Outcome Measures

Name	Time	Method
Difference of interoception behavioural scores between FND patients and Healthy controls	1 day	Assessment of the difference between interoception tasks scores between these groups. These scores evaluated the interoception processing abilities of patient/control.
Difference in brain electrophysiology during interoception processing between FND patients and Healthy controls	1 day	Assessment of the difference Evoked Related potential (ERPs) during interoception taks between these groups.
Association between oxytocin system and interoception and its difference between FND patients and Healthy controls	1 day	Study of the correlation between oxytocin system and interoception indices. Oxytocin system was studied with oxytocin concentration (saliva) and genetic markers (blood analysis).

Secondary Outcome Measures

Name	Time	Method
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task2	1 day	First, study the difference of mismatch negativity (MMN) evoked potential either if external tone was synchronous or asynchronous with heartbeat. Then comparison between FND patients and healthy control.
Oxytocin concentration (Saliva sampling)	1 day	During the day of the experimental session, 4 samples of saliva at different time are collected. These sample will be used to determine the concentration of oxytocin during the day (30 min post awakening, 30min after lunch, at tasks, upon the arrival for experimental session, after the completion of all tasks).
Epigenetic profile	1 day	Blood sample are used for genetic analysis on the oxytocin markers (such as allele-frequency in the oxytonergic receptor gene). Correlation of this with interoceptive scores.
Respiratory Resistance Sensitivity	1 day	Difference of accuracy between FND patients and healthy control in the respiratory resistance sensitivity task.
Neurophysiological measures: Correlation between agency task and respiration cycle (Libet)	1 day	Study of the correlation between a free will key press and the state in respiration cycle. Then comparison of the results between FND patients and healthy control.
Behavioral measure: Correlation between oxytocin and clinical questionaire	1 day	Correlating the scores or categories of childhood trauma, attachment style and sexual functioning to oxytocin levels.
Behavioral measure: heartbeat counting	1 day	Difference of accuracy between FND patients and healthy control to count the number of their own heartbeats.
Electrophysiological measure (EEG): the readiness potential (Libet)	1 day	Analysing the readiness potential related with the motor movement in the implicit compared to the explicit trigger. Then comparison of the results between FND patients and healthy control.
The localization of neuronal activity derived from EEG during interoceptive tasks, and during resting state	1 day	Use of the EEG signal during cardiac interception task (HEP),agency task (Libet) and resting to estimate the source generator of brain activities (inverse solution).
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task1	1 day	First, study the HEP difference between interoceptive tones (the own heartbeat) with a control condition of focusing on exteroceptive tones (sounds played). Then comparison between FND patients and healthy control.

Trial Locations

Locations (2)

Inselspital; 🇨🇭 Bern, Switzerland

University of Fribourg; 🇨🇭 Fribourg, Switzerland