[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"health-study-detail:100652287":3},{"organization":4,"armGroups":7,"interventions":21,"overallOfficials":39,"centralContacts":43,"locations":49,"responsibleParty":65,"collaborators":26,"id":67,"slug":68,"hasResults":69,"nctId":70,"briefTitle":71,"officialTitle":71,"acronym":72,"eligibilityCriteria":73,"healthyVolunteers":74,"sex":75,"minAge":76,"maxAge":77,"enrollmentInfo":78,"targetDuration":26,"studyType":81,"phases":82,"briefSummary":84,"conditions":85,"keywords":89,"overallStatus":100,"whyStopped":26,"lastUpdateSubmitDate":101,"lastUpdatePostDateStruct":102,"startDateStruct":105,"completionDateStruct":107,"leadSponsor":109,"locationsCount":110},{"fullName":5,"class":6},"University of Fribourg","OTHER",[8,17],{"label":9,"type":10,"description":11,"interventionNames":12},"Sequence A: synchronous-first (normal-breathing block)","EXPERIMENTAL","Sequence A: synchronous-first (normal-breathing block):\n\nRandomised sequence group A. Participants complete all four cells of the 2x2 design in a single experimental visit: the normal-breathing block first (fixed order), then the hyperventilation block. In the normal-breathing block this group receives the SYNCHRONOUS respiratory-visual VR exposure first and the asynchronous exposure second. In the hyperventilation block the participant is separately allocated, from the same pre-generated permuted-block randomisation list, one of six balanced sequences comprising two synchronous and two asynchronous VR exposures; the list is balanced on the first-exposure condition. The interventions received are identical to those in Sequence B, and only the order of the synchronous and asynchronous VR exposures differs. Open label.",[13,14,15,16],"Other: Voluntary hyperventilation (guided paced breathing)","Other: Normal spontaneous breathing (within-subject control)","Other: Synchronous respiratory-visual VR feedback","Other: Asynchronous respiratory-visual VR feedback",{"label":18,"type":10,"description":19,"interventionNames":20},"Sequence B: asynchronous-first (normal-breathing block)","Randomised sequence group B. Participants complete all four cells of the 2x2 design in a single experimental visit: the normal-breathing block first (fixed order), then the hyperventilation block. In the normal-breathing block this group receives the ASYNCHRONOUS respiratory-visual VR exposure first and the synchronous exposure second. In the hyperventilation block the participant is separately allocated, from the same pre-generated permuted-block randomisation list, one of six balanced sequences comprising two synchronous and two asynchronous VR exposures; the list is balanced on the first-exposure condition. The interventions received are identical to those in Sequence A, and only the order of the synchronous and asynchronous VR exposures differs. Open label.",[13,14,15,16],[22,27,31,35],{"type":6,"name":23,"description":24,"armGroupLabels":25,"otherNames":26},"Voluntary hyperventilation (guided paced breathing)","Participants breathe deeper and faster than normal, maintaining continuous cyclic breathing without pauses between inhalation and exhalation, paced by a pre-recorded standardised voice guide in German or English with background music. The hyperventilation block comprises four cycles, each with a 10-minute guided paced-hyperventilation induction, a 2-minute VR exposure and a 3-minute post-exposure stack (BSC-Q, Mental Imagery Task, distress NRS); cycle 1 additionally includes a 2-minute hyperventilation-state Mental Imagery Task pre-test between the induction and the VR exposure. A 5-minute sustained-hyperventilation resting-state EEG window is collected between cycles 2 and 3, with the voice guide replaced by a soft drum pacing tone. Cumulative hyperventilation is approximately 45 minutes, followed by a single supervised recovery. EtCO2, SpO2, heart rate and heart rate variability (ECG) are monitored continuously under the protocol's tiered stop criteria.",[9,18],null,{"type":6,"name":28,"description":29,"armGroupLabels":30,"otherNames":26},"Normal spontaneous breathing (within-subject control)","Within-subject control condition for the Breathing factor. Participants breathe at their natural spontaneous rate while receiving audio guidance from the same pre-recorded standardised voice guide and background music used in the hyperventilation condition, so that the auditory environment is held constant across conditions and only the breathing instruction differs. Delivered as two 8-minute normal-breathing cycles (3 minutes spontaneous breathing in VR, a 2-minute VR exposure, and a 3-minute post-exposure stack of BSC-Q, Mental Imagery Task and distress NRS), one with synchronous and one with asynchronous respiratory-visual feedback, seated in the experimental chair wearing the head-mounted display.",[9,18],{"type":6,"name":32,"description":33,"armGroupLabels":34,"otherNames":26},"Synchronous respiratory-visual VR feedback","Respiratory-visual VR paradigm delivering contingent feedback; this is the measurement method through which bodily self-consciousness is assessed. Seated participants wear a head-mounted display showing a first-person view of a three-dimensional virtual body positioned about 2 metres in front of the viewpoint and seen from behind. A respiratory belt at the level of the umbilicus drives, in real time, a luminous halo surrounding the virtual body: the halo becomes increasingly visible during inspiration, reaches maximum luminosity at peak inspiration and fades during expiration, in synchrony with the participant's actual breathing. Each exposure lasts 2 minutes (120 seconds). Each participant receives one synchronous exposure in the normal-breathing block and two in the hyperventilation block.",[9,18],{"type":6,"name":36,"description":37,"armGroupLabels":38,"otherNames":26},"Asynchronous respiratory-visual VR feedback","Respiratory-visual VR paradigm delivering non-contingent feedback; the control level of the Synchrony factor. Setup is identical to the synchronous condition (seated, head-mounted display, virtual body about 2 metres in front seen from behind, respiratory belt at the umbilicus), except that the halo modulation is phase-shifted and frequency-adjusted to 80% or 120% of the measured breathing frequency, so that the visual feedback never corresponds to the participant's respiratory state. Each exposure lasts 2 minutes (120 seconds). Each participant receives one asynchronous exposure in the normal-breathing block and two in the hyperventilation block.",[9,18],[40],{"name":41,"affiliation":5,"role":42},"Gregor Hasler, Prof. Dr. med.","PRINCIPAL_INVESTIGATOR",[44],{"name":45,"role":46,"phone":47,"phoneExt":26,"email":48},"Parsa Yousefi, Mas","CONTACT","+41 26 308 16 03","parsa.yousefi@unifr.ch",[50],{"facility":51,"status":26,"city":52,"state":26,"zip":53,"country":54,"countryCode":55,"cosmosGeoPoint":56,"geoPoint":61,"contacts":62},"University of Fribourg, Molecular Psychiatry Laboratory, (at Réseau fribourgeois de santé mentale, RFSM\u002FFNPG)","Villars-sur-Glâne","1752","Switzerland","CH",{"type":57,"coordinates":58},"Point",[59,60],7.11717,46.79054,{"lat":60,"lon":59},[63],{"name":64,"role":46,"phone":47,"phoneExt":26,"email":48},"Parsa Yousefi",{"type":66,"investigatorFullName":26,"investigatorTitle":26,"investigatorAffiliation":26,"oldNameTitle":26,"oldOrganization":26},"SPONSOR","100652287","hyperventilation-effects-on-bodily-self-consciousness-100652287",false,"NCT07769710","Hyperventilation Effects on Bodily Self-Consciousness","HYPERSELF","Inclusion Criteria:\n\n* Healthy adult aged 18-55 years\n* Able to provide written informed consent\n* Normal or corrected-to-normal vision\n* Sufficient German or English to follow instructions and complete questionnaires\n* Tolerates the \\~5-minute VR-guided hyperventilation test at screening\n\nExclusion Criteria:\n\n* Cardiovascular or cerebrovascular disease posing a risk during hyperventilation (e.g., myocardial infarction or stroke within 12 months, significant\u002Funstable cardiac disease, heart failure, uncontrolled\u002Fsevere hypertension, aneurysm, Moyamoya)\n* Respiratory disease (asthma, COPD, restrictive lung disease, pulmonary fibrosis, recent severe lung infection, dyspnoea at rest)\n* Haematological disease (sickle cell disease or trait, severe anaemia)\n* Neurological disease (epilepsy or seizures, severe\u002Frecurrent migraine, neurodegenerative disorder)\n* Psychiatric disorder (panic or severe anxiety disorder, psychosis or schizophrenia, severe bipolar disorder, acute major depression, acute addiction)\n* Metabolic disease (Type 1 or poorly controlled Type 2 diabetes, BMI \\> 35)\n* Pregnancy (confirmed by urine test at screening) or planned pregnancy during the study period\n* Medication affecting respiration or brain function\n* Physical inability to cooperate or to remain seated for the \\~188-minute experimental visit\n* Insufficient understanding of study procedures and risks\n* Intolerable reaction to the hyperventilation tolerance test at screening",true,"ALL","18 Years","55 Years",{"count":79,"type":80},35,"ESTIMATED","INTERVENTIONAL",[83],"NA","This study examines how voluntary fast, deep breathing (hyperventilation) affects the way healthy adults perceive their own body. Participants wear a virtual-reality (VR) headset and see a virtual body; a glowing halo around it either pulses exactly in time with their own breathing or is time-shifted. During the study, breathing, heart activity, blood-oxygen level, the carbon-dioxide content of exhaled air, and brain activity (EEG, measured non-invasively from the scalp) are recorded continuously, and participants complete questionnaires about their experience.\n\nThe aim is to understand whether and how altered breathing changes the interplay between what people see and what they feel inside their body, and thereby the sense of being located within one's own body. The study uses a 2×2 within-subjects design crossing Breathing (normal vs. hyperventilation) with Visual synchrony (synchronous vs. asynchronous), with the asynchronous and normal-breathing conditions serving as within-subject controls.\n\nNo medication is administered and no medical device is being tested; the instruments used serve only for monitoring and measurement. Participation involves a screening visit (including a short, \\~5-minute guided-hyperventilation tolerance test) and an experimental visit.",[86,87,88],"Bodily Self-Consciousness","Interoception","Healthy Volunteers",[90,91,92,93,94,95,96,97,98,99],"hyperventilation","bodily self-consciousness","full-body illusion","respiratory-visual synchrony","interoception","virtual reality","EEG","heartbeat-evoked potential","altered states of consciousness","breathwork","NOT_YET_RECRUITING","2026-08-12",{"date":103,"type":104},"2026-08-18","ACTUAL",{"date":106,"type":80},"2026-09-01",{"date":108,"type":80},"2027-07-31",{"name":5,"class":6},1]