NCT06084325

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).

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
110

participants targeted

Target at P50-P75 for all trials

Timeline
Completed

Started Oct 2023

Geographic Reach
1 country

2 active sites

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

First Submitted

Initial submission to the registry

September 20, 2023

Completed
15 days until next milestone

Study Start

First participant enrolled

October 5, 2023

Completed
11 days until next milestone

First Posted

Study publicly available on registry

October 16, 2023

Completed
1.3 years until next milestone

Primary Completion

Last participant's last visit for primary outcome

January 24, 2025

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

January 24, 2025

Completed
Last Updated

March 27, 2025

Status Verified

March 1, 2025

Enrollment Period

1.3 years

First QC Date

September 20, 2023

Last Update Submit

March 24, 2025

Conditions

Outcome Measures

Primary Outcomes (3)

  • Difference of interoception behavioural scores between FND patients and Healthy controls

    Assessment of the difference between interoception tasks scores between these groups. These scores evaluated the interoception processing abilities of patient/control.

    1 day

  • Difference in brain electrophysiology during interoception processing between FND patients and Healthy controls

    Assessment of the difference Evoked Related potential (ERPs) during interoception taks between these groups.

    1 day

  • Association between oxytocin system and interoception and its difference between FND patients and Healthy controls

    Study of the correlation between oxytocin system and interoception indices. Oxytocin system was studied with oxytocin concentration (saliva) and genetic markers (blood analysis).

    1 day

Secondary Outcomes (10)

  • Oxytocin concentration (Saliva sampling)

    1 day

  • Epigenetic profile

    1 day

  • Respiratory Resistance Sensitivity

    1 day

  • Behavioral measure: heartbeat counting

    1 day

  • Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task1

    1 day

  • +5 more secondary outcomes

Study Arms (2)

FND Patients

Group of patients with functional neurological disorders

Device: Respiration resistance sensitivity task (RRST)Behavioral: Heartbeat Tracking (HBT)Device: Heartbeat evoked potential (HEP)Device: Libet task

Healthy control

Age matched group control of healthy participant

Device: Respiration resistance sensitivity task (RRST)Behavioral: Heartbeat Tracking (HBT)Device: Heartbeat evoked potential (HEP)Device: Libet task

Interventions

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.

Also known as: Respiration resistance device
FND PatientsHealthy control

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).

Also known as: ECG
FND PatientsHealthy control

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.

Also known as: ECG + EEG
FND PatientsHealthy control

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.

Also known as: Respiration belt + EEG
FND PatientsHealthy control

Eligibility Criteria

Age18 Years+
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64), Older Adult (65+)
Sampling MethodNon-Probability Sample
Study Population

FND patients Participants who are patients will be recruited from the in- and out-patients pool of the Clinic for Neurology of the Hospital of Fribourg and the Inselspital. At both, the treating physician will identify suitable patients (i.e. patients who fulfil the clinical requirement for FND as described in the DSM-5). The treating physician will ask these patients whether they would like to be approached by the Investigator (or his/her designee) concerning a scientific study. In case of affirmative response, the Investigator will approach the patients, inform them about the study. Healthy control Healthy controls will be recruited among students, collaborators, and visitors of the University of Fribourg and Bern, the Hospital of Fribourg and the Inselspital. They will be recruited by flyer, by word-of-mouth and through advertisements in public media.

You may qualify if:

  • 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)

You may not qualify if:

  • 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
  • +4 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (2)

Inselspital

Bern, Canton of Bern, 3010, Switzerland

Location

University of Fribourg

Fribourg, Canton of Fribourg, 1700, Switzerland

Location

Biospecimen

Retention: SAMPLES WITH DNA

7.5 ml of blood (2 x 3.4ml EDTA) are taken from the test persons. The DNA is then extracted from the blood using the QIAamp DNA Blood Mini Kit (QIAGEN, Germany).

MeSH Terms

Conditions

Conversion Disorder

Interventions

ElectrocardiographyElectroencephalography

Condition Hierarchy (Ancestors)

Somatoform DisordersMental Disorders

Intervention Hierarchy (Ancestors)

Heart Function TestsDiagnostic Techniques, CardiovascularDiagnostic Techniques and ProceduresDiagnosisElectrodiagnosisDiagnostic Techniques, Neurological

Study Design

Study Type
observational
Observational Model
CASE CONTROL
Time Perspective
PROSPECTIVE
Sponsor Type
OTHER
Responsible Party
SPONSOR

Study Record Dates

First Submitted

September 20, 2023

First Posted

October 16, 2023

Study Start

October 5, 2023

Primary Completion

January 24, 2025

Study Completion

January 24, 2025

Last Updated

March 27, 2025

Record last verified: 2025-03

Data Sharing

IPD Sharing
Will not share

Locations