Functional Neurological DisorderNCT06084325
The Role of Oxytocin and Interoception in Functional Neurological Disorder
An observational study of Functional Neurological Disorder, run by University of Fribourg at 2 sites in Switzerland.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Functional Neurological Disorder
- What is being tested?
- Respiration resistance sensitivity task (RRST), Heartbeat Tracking (HBT) and Heartbeat evoked potential (HEP)
- Type of treatment
- Medical device, Lifestyle or therapy programme
- How many people
- 110 participants
- Where
- 2 sitesSwitzerland
- Study dates
- 5 Oct 2023to 24 Jan 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
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.
Who may be able to join
- 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)
Who cannot join
- 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
Show all 19Show fewer
- 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
Trial locations and contacts
2 sites in 1 country.
Switzerland2 sites
Inselspital
Bern, Canton of Bern, 3010
University of Fribourg
Fribourg, Canton of Fribourg, 1700
About this study
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).
Read the 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:
- 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:
- 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
- Being tested
- Respiration resistance sensitivity task (RRST), Heartbeat Tracking (HBT), Heartbeat evoked potential (HEP), Libet task
- Medical subject headings
- Conversion Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Respiration resistance sensitivity task (RRST)Device
Also called Respiration resistance 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)Behavioural
Also called ECG
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)Device
Also called ECG + EEG
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 taskDevice
Also called Respiration belt + EEG
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.
| Study group | Role | What they receive |
|---|---|---|
| FND Patients | Group of patients with functional neurological disorders Receives: 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 Receives: Device: Respiration resistance sensitivity task (RRST); Behavioral: Heartbeat Tracking (HBT); Device: Heartbeat evoked potential (HEP); Device: Libet task |
What is being measured
The primary outcome is the main question the study is designed to answer.
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.
Measured: 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.
Measured: 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).
Measured: 1 day
Secondary outcomes (10)
Oxytocin concentration (Saliva sampling)
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).
Measured: 1 day
Epigenetic profile
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.
Measured: 1 day
Respiratory Resistance Sensitivity
Difference of accuracy between FND patients and healthy control in the respiratory resistance sensitivity task.
Measured: 1 day
Behavioral measure: heartbeat counting
Difference of accuracy between FND patients and healthy control to count the number of their own heartbeats.
Measured: 1 day
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task1
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.
Measured: 1 day
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task2
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.
Measured: 1 day
Neurophysiological measures: Correlation between agency task and respiration cycle (Libet)
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.
Measured: 1 day
Electrophysiological measure (EEG): the readiness potential (Libet)
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.
Measured: 1 day
The localization of neuronal activity derived from EEG during interoceptive tasks, and during resting state
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).
Measured: 1 day
Behavioral measure: Correlation between oxytocin and clinical questionaire
Correlating the scores or categories of childhood trauma, attachment style and sexual functioning to oxytocin levels.
Measured: 1 day
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Oct 2023
- Study start5 Oct 2023
- Primary completion24 Jan 2025
- Study completion24 Jan 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Functional Neurological DisorderStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Prospective
- Enrolment
- 110 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Fribourg
- Sponsor type
- University, hospital or other
- Collaborators
- Insel Gruppe AG, University Hospital Bern
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06084325
- Sponsor's protocol ID
- 2023-00469
- Other IDs
- 2023
- Status last verified
- Mar 2025
- First submitted
- 20 Sep 2023
- Last updated
- 27 Mar 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 27 Mar 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Role of Oxytocin and Interoception in Functional Neurological Disorder
- ClinicalTrials.gov ID
- NCT06084325
- Acronym / sponsor ID
- 2023-00469
- Conditions
- Functional Neurological Disorder
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 110 participants (actual)
- Lead sponsor
- University of FribourgUniversity, hospital or other
- Collaborators
- Insel Gruppe AG, University Hospital Bern
- Study start
- 5 Oct 2023 (actual)
- Primary completion
- 24 Jan 2025 (actual)
- Study completion
- 24 Jan 2025 (actual)
- First posted
- 16 Oct 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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:
- 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:
- 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 design
- Observational model
- Case-control
- Time perspective
- Prospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| FND Patients | – | Device: Respiration resistance sensitivity task (RRST), Behavioral: Heartbeat Tracking (HBT), Device: Heartbeat evoked potential (HEP), Device: Libet taskGroup of patients with functional neurological disorders |
| Healthy control | – | Device: Respiration resistance sensitivity task (RRST), Behavioral: Heartbeat Tracking (HBT), Device: Heartbeat evoked potential (HEP), Device: Libet taskAge matched group control of healthy participant |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- 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.
Key inclusion criteria (5 listed)
- 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)
Key exclusion criteria (19 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Respiration resistance sensitivity task (RRST)Also: Respiration resistance deviceThe 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. | Device | FND Patients, Healthy control |
| Heartbeat Tracking (HBT)Also: ECGThe 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). | Behavioural | FND Patients, Healthy control |
| Heartbeat evoked potential (HEP)Also: ECG + EEGThe 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 | FND Patients, Healthy control |
| Libet taskAlso: Respiration belt + EEGAdditionally 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. | Device | FND Patients, Healthy control |
Primary outcome
Difference of interoception behavioural scores between FND patients and Healthy controls
Time frame: 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
Time frame: 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
Time frame: 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).
10 secondary outcomes
Oxytocin concentration (Saliva sampling)
Time frame: 1 day
Epigenetic profile
Time frame: 1 day
Respiratory Resistance Sensitivity
Time frame: 1 day
Behavioral measure: heartbeat counting
Time frame: 1 day
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task1
Time frame: 1 day
Electrophysiological measure (EEG): Heartbeat evoked potential (HEP) task2
Time frame: 1 day
Neurophysiological measures: Correlation between agency task and respiration cycle (Libet)
Time frame: 1 day
Electrophysiological measure (EEG): the readiness potential (Libet)
Time frame: 1 day
The localization of neuronal activity derived from EEG during interoceptive tasks, and during resting state
Time frame: 1 day
Behavioral measure: Correlation between oxytocin and clinical questionaire
Time frame: 1 day
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Mar 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Functional Neurological Disorder, run by University of Fribourg at 2 sites in Switzerland.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 27 Mar 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference of interoception behavioural scores between FND patients and Healthy controls (time frame: 1 day). The study lists 3 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Mar 2025; AzTrials last refreshed its copy on 8 Nov 2026.