The Role of Oxytocin and Interoception in Functional Neurological Disorder

NCT ID: NCT06084325

Last Updated: 2025-03-27

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Total Enrollment

110 participants

Study Classification

OBSERVATIONAL

Study Start Date

2023-10-05

Study Completion Date

2025-01-24

Brief Summary

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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

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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

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Functional Neurological Disorder

Study Design

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Observational Model Type

CASE_CONTROL

Study Time Perspective

PROSPECTIVE

Study Groups

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FND Patients

Group of patients with functional neurological disorders

Respiration resistance sensitivity task (RRST)

Intervention Type DEVICE

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.

Heartbeat Tracking (HBT)

Intervention Type BEHAVIORAL

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).

Heartbeat evoked potential (HEP)

Intervention Type DEVICE

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.

Libet task

Intervention Type DEVICE

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.

Healthy control

Age matched group control of healthy participant

Respiration resistance sensitivity task (RRST)

Intervention Type DEVICE

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.

Heartbeat Tracking (HBT)

Intervention Type BEHAVIORAL

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).

Heartbeat evoked potential (HEP)

Intervention Type DEVICE

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.

Libet task

Intervention Type DEVICE

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.

Interventions

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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.

Intervention Type DEVICE

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).

Intervention Type BEHAVIORAL

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.

Intervention Type 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.

Intervention Type DEVICE

Other Intervention Names

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Respiration resistance device ECG ECG + EEG Respiration belt + EEG

Eligibility Criteria

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Inclusion Criteria

* 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)


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

Exclusion Criteria

* 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


* 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
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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Insel Gruppe AG, University Hospital Bern

OTHER

Sponsor Role collaborator

University of Fribourg

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Inselspital

Bern, Canton of Bern, Switzerland

Site Status

University of Fribourg

Fribourg, Canton of Fribourg, Switzerland

Site Status

Countries

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Switzerland

Other Identifiers

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2023-00469

Identifier Type: -

Identifier Source: org_study_id

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