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Hyperventilation Effects on Bodily Self-Consciousness (HYPERSELF)

2026年8月12日 更新者：University of Fribourg

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.

The 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.

No 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.

研究概览

地位

尚未招聘

条件

干预/治疗

详细说明

Background and rationale. Bodily self-consciousness (BSC) - the sense of owning a body and being located within it - depends on integrating exteroceptive (e.g., visual) and interoceptive (e.g., respiratory, cardiac) signals. Voluntary hyperventilation induces marked interoceptive and physiological changes and can alter states of consciousness. This study investigates whether hyperventilation modulates the visually driven manipulation of BSC, using a respiratory-visual full-body illusion.

Design. Single-centre experimental study with a 2x2 within-subjects design crossing Breathing (normal vs. voluntary paced hyperventilation) and Visual synchrony (a virtual body whose surrounding luminous halo is modulated synchronously vs. asynchronously with the participant's real-time respiration, recorded via a respiratory belt). The block order is fixed, with the normal-breathing block always preceding the hyperventilation block for safety and physiological reasons; within each block, the order of the synchronous and asynchronous VR exposures is randomised across participants from a computer-generated permuted-block list prepared before enrolment. The asynchronous and normal-breathing conditions serve as within-subject controls.

Intervention. Voluntary, guided paced hyperventilation is delivered as four cycles of approximately 10 minutes of deepened breathing under audio guidance (including a sustained-hyperventilation window for EEG), with continuous physiological monitoring: end-tidal CO2 (capnography), pulse oximetry (SpO2 and heart rate), ECG, and direct observation by trained study staff. After each breathing cycle, participants view for about 2 minutes a virtual body (avatar) positioned about 2 m ahead and seen from behind, in a first-person perspective, with the halo modulated synchronously or asynchronously with breathing. A normal, quiet-breathing condition in the same VR environment serves as the comparison.

Procedures. The study comprises two visits: (1) a screening visit with informed consent, health-history review, baseline physiology, and a short (~5-minute) VR-guided hyperventilation familiarisation/tolerance test; and (2) an experimental visit (~188 minutes) with the full protocol. A urine pregnancy test is performed at screening for participants of childbearing potential. Safety is governed by predefined tiered stop criteria and a recovery/discharge checklist, with an on-site emergency physician available for escalation.

No medicinal product is administered and no medical device is under investigation; all instruments are used within their intended purpose for monitoring and measurement. The study is an "other clinical trial" under Swiss law (Chapter 4 ClinO), risk category B, reviewed by the Cantonal Ethics Committee Bern (BASEC 2026-01385).

研究类型

介入性

注册 (估计的)

35

阶段

  • 不适用

联系人和位置

本节提供了进行研究的人员的详细联系信息，以及有关进行该研究的地点的信息。

学习联系方式

学习地点

  • 瑞士
      • Villars-sur-Glâne、瑞士、1752
        • University of Fribourg, Molecular Psychiatry Laboratory, (at Réseau fribourgeois de santé mentale, RFSM/FNPG)
        • 接触：

参与标准

研究人员寻找符合特定描述的人，称为资格标准。这些标准的一些例子是一个人的一般健康状况或先前的治疗。

资格标准

适合学习的年龄

  • 成人

接受健康志愿者

是的

描述

Inclusion Criteria:

  • Healthy adult aged 18-55 years
  • Able to provide written informed consent
  • Normal or corrected-to-normal vision
  • Sufficient German or English to follow instructions and complete questionnaires
  • Tolerates the ~5-minute VR-guided hyperventilation test at screening

Exclusion Criteria:

  • Cardiovascular or cerebrovascular disease posing a risk during hyperventilation (e.g., myocardial infarction or stroke within 12 months, significant/unstable cardiac disease, heart failure, uncontrolled/severe hypertension, aneurysm, Moyamoya)
  • Respiratory disease (asthma, COPD, restrictive lung disease, pulmonary fibrosis, recent severe lung infection, dyspnoea at rest)
  • Haematological disease (sickle cell disease or trait, severe anaemia)
  • Neurological disease (epilepsy or seizures, severe/recurrent migraine, neurodegenerative disorder)
  • Psychiatric disorder (panic or severe anxiety disorder, psychosis or schizophrenia, severe bipolar disorder, acute major depression, acute addiction)
  • Metabolic disease (Type 1 or poorly controlled Type 2 diabetes, BMI > 35)
  • Pregnancy (confirmed by urine test at screening) or planned pregnancy during the study period
  • Medication affecting respiration or brain function
  • Physical inability to cooperate or to remain seated for the ~188-minute experimental visit
  • Insufficient understanding of study procedures and risks
  • Intolerable reaction to the hyperventilation tolerance test at screening

学习计划

本节提供研究计划的详细信息，包括研究的设计方式和研究的衡量标准。

研究是如何设计的？

设计细节

  • 主要用途：基础科学
  • 分配：随机化
  • 介入模型：交叉作业
  • 屏蔽：无（打开标签）

武器和干预

参与者组/臂
干预/治疗
实验性的：Sequence A: synchronous-first (normal-breathing block)

Sequence A: synchronous-first (normal-breathing block):

Randomised 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.
其他：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.
其他：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.
其他：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.
其他：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.
实验性的：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.
其他：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.
其他：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.
其他：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.
其他：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.

研究衡量的是什么？

主要结果指标

结果测量
措施说明
大体时间
Mean Rating of Perceived Breathing Location in the Virtual Body: Bodily Self-Consciousness Questionnaire Item 1 (BSC-Q1)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "It seemed as if I was feeling my respiration in the virtual body", item 1 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. Higher scores indicate that the participant's own breathing is felt more strongly to be located in the virtual body (a stronger illusion). This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Primary analysis: the Synchrony x Breathing interaction in a within-subjects linear mixed-effects model.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures

次要结果测量

结果测量
措施说明
大体时间
Mean Drift in Perceived Self-Location Toward the Virtual Body, Measured With the Mental Imagery Task (MIT)
大体时间：Experimental visit (single visit, approximately 188 minutes); measured after each of the 6 VR exposures, each baseline-corrected against a matched breathing-state pre-test
Behavioural measure of perceived self-location, reported in centimetres. Participants stand still in virtual reality and watch a ball approach along the anterior-posterior body axis; the ball then disappears and they press a button when they imagine it reaching their own position. The position of the hidden ball along that axis at the moment of the button press is recorded as the estimate of perceived self-location (method of Nakul et al., Sci Rep 2020;10:6802, which records self-location as an anterior-posterior coordinate and reports drifts in centimetres). One value is reported per participant per condition: the drift, calculated as the coordinate recorded after the VR exposure minus the participant's own matched breathing-state pre-test coordinate. Positive values indicate relocation toward the virtual body; larger positive values indicate a stronger illusion. Secondary endpoint, analysed as the Synchrony x Breathing interaction in a mixed-effects model.
Experimental visit (single visit, approximately 188 minutes); measured after each of the 6 VR exposures, each baseline-corrected against a matched breathing-state pre-test
Mean Rating of Perceived Breathing Synchrony With the Virtual Body: Bodily Self-Consciousness Questionnaire Item 2 (BSC-Q2)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "I felt as if the virtual body was breathing with me", item 2 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. Higher scores indicate a stronger sense that the virtual body was breathing together with the participant. This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Secondary endpoint, analysed with a mixed-effects model analogous to the primary endpoint and reported with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Mean Rating of Self-Identification With the Virtual Body: Bodily Self-Consciousness Questionnaire Item 3 (BSC-Q3)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "I felt as if the virtual body was my body", item 3 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. Higher scores indicate stronger self-identification with the virtual body. This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Secondary endpoint, analysed with a mixed-effects model analogous to the primary endpoint and reported with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Mean Rating of Being Located Outside the Physical Body: Bodily Self-Consciousness Questionnaire Item 4 (BSC-Q4)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "I felt as if I was outside my physical body", item 4 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. Higher scores indicate a stronger sensation of being located outside the physical body. This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Secondary endpoint, analysed with a mixed-effects model analogous to the primary endpoint and reported with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Mean Rating of Separation From the Physical Body: Bodily Self-Consciousness Questionnaire Item 5 (BSC-Q5)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "I felt as if I was separated from my physical body", item 5 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. Higher scores indicate a stronger sensation of being separated from the physical body. This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Secondary endpoint, analysed with a mixed-effects model analogous to the primary endpoint and reported with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Mean Rating on the Control Item: Bodily Self-Consciousness Questionnaire Item 6 (BSC-Q6)
大体时间：Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Self-reported agreement with the statement "It seemed as if I had more than two bodies", item 6 of the Bodily Self-Consciousness Questionnaire (BSC-Q). Rated on a 7-point Likert scale from -3 (totally disagree) to +3 (totally agree); minimum -3, maximum +3. BSC-Q6 is a pre-specified control item on which no synchrony effect is expected; it detects response bias and does not index the illusion. Higher scores indicate stronger endorsement of an experience not expected to occur. This is a mechanistic outcome; neither a higher nor a lower score is a better or worse clinical outcome. Rated after each of the 6 virtual reality (VR) exposures (2 normal-breathing exposures, 4 hyperventilation cycles); the two hyperventilation cycles at each synchrony level are averaged within participant. Reported as the mean rating in each of the 4 conditions (Synchronous/Asynchronous x Normal breathing/Hyperventilation). Secondary endpoint, reported with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); rated after each of the 6 VR exposures
Mean Score on the Oceanic Boundlessness Dimension of the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Dimension score from the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC), a 94-item retrospective self-report instrument completed once at the end of the experimental session, within 30 minutes of the end of the hyperventilation block, and referring to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale and each dimension score is expressed on that same scale; minimum 0, maximum 100. This outcome measure reports the Oceanic Boundlessness dimension only; the other four 5D-ASC dimensions are reported as separate outcome measures. Higher scores indicate a more pronounced altered state on this dimension. The measure is descriptive and phenomenological; neither a higher nor a lower score is a better or worse clinical outcome. Secondary endpoint, reported descriptively and exploratorily with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Score on the Anxious Ego Dissolution Dimension of the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Dimension score from the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC), a 94-item retrospective self-report instrument completed once at the end of the experimental session, within 30 minutes of the end of the hyperventilation block, and referring to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale and each dimension score is expressed on that same scale; minimum 0, maximum 100. This outcome measure reports the Anxious Ego Dissolution dimension only; the other four 5D-ASC dimensions are reported as separate outcome measures. Higher scores indicate a more pronounced altered state on this dimension. The measure is descriptive and phenomenological; neither a higher nor a lower score is a better or worse clinical outcome. Secondary endpoint, reported descriptively and exploratorily with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Score on the Visionary Restructuralization Dimension of the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Dimension score from the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC), a 94-item retrospective self-report instrument completed once at the end of the experimental session, within 30 minutes of the end of the hyperventilation block, and referring to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale and each dimension score is expressed on that same scale; minimum 0, maximum 100. This outcome measure reports the Visionary Restructuralization dimension only; the other four 5D-ASC dimensions are reported as separate outcome measures. Higher scores indicate a more pronounced altered state on this dimension. The measure is descriptive and phenomenological; neither a higher nor a lower score is a better or worse clinical outcome. Secondary endpoint, reported descriptively and exploratorily with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Score on the Auditory Alterations Dimension of the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Dimension score from the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC), a 94-item retrospective self-report instrument completed once at the end of the experimental session, within 30 minutes of the end of the hyperventilation block, and referring to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale and each dimension score is expressed on that same scale; minimum 0, maximum 100. This outcome measure reports the Auditory Alterations dimension only; the other four 5D-ASC dimensions are reported as separate outcome measures. Higher scores indicate a more pronounced altered state on this dimension. The measure is descriptive and phenomenological; neither a higher nor a lower score is a better or worse clinical outcome. Secondary endpoint, reported descriptively and exploratorily with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Score on the Reduction of Vigilance Dimension of the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Dimension score from the 5-Dimensional Altered States of Consciousness Rating Scale (5D-ASC), a 94-item retrospective self-report instrument completed once at the end of the experimental session, within 30 minutes of the end of the hyperventilation block, and referring to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale and each dimension score is expressed on that same scale; minimum 0, maximum 100. This outcome measure reports the Reduction of Vigilance dimension only; the other four 5D-ASC dimensions are reported as separate outcome measures. Higher scores indicate a more pronounced altered state on this dimension. The measure is descriptive and phenomenological; neither a higher nor a lower score is a better or worse clinical outcome. Secondary endpoint, reported descriptively and exploratorily with uncorrected p-values.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Item Score on the Six-Dimensional Extended Bodily Self-Consciousness Scale (6D-xBSC)
大体时间：Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Overall score on the 6D-xBSC, an exploratory in-house 41-item scale characterising hyperventilation-induced changes in the bodily self. The questionnaire is completed once, retrospectively, within 30 minutes of the end of the hyperventilation block, and refers to the hyperventilation block as a whole. Every item is rated on a 0-100 visual analogue scale; minimum 0, maximum 100. One value is reported per participant: the mean of the 41 item ratings, expressed on the same 0-100 scale. Higher scores indicate stronger disruption of bodily self-consciousness; the measure is descriptive and phenomenological, so neither a higher nor a lower score is a better or worse clinical outcome. The scale targets six bodily-self dimensions, but its factor structure has not been validated; dimension-level scores are therefore not pre-specified outcome measures and any dimensional scoring will be determined by exploratory analysis after data collection. Secondary endpoint, reported descriptively.
Experimental visit (single visit, approximately 188 minutes); completed once at the end of the session, within 30 minutes of the hyperventilation block
Mean Amplitude of the Heartbeat-Evoked Potential (HEP) in Microvolts Over the Frontocentral Electrode Cluster
大体时间：Experimental visit (single visit, approximately 188 minutes)
Amplitude of the heartbeat-evoked potential (HEP): one EEG parameter, reported in microvolts. Scalp EEG (32 channels) and ECG are recorded continuously throughout the experimental visit. EEG epochs time-locked to the ECG R-peak are averaged, and HEP amplitude is the mean voltage of that averaged waveform across one pre-specified post-R-peak time window and one pre-specified frontocentral electrode cluster. No other EEG parameter (for example spectral power) is reported under this outcome measure. One value per participant per condition: epochs are averaged within condition to give one HEP amplitude for each of the four within-subject cells (Synchronous/Normal, Asynchronous/Normal, Synchronous/Hyperventilation, Asynchronous/Hyperventilation), which enter one mixed-effects model with Synchrony and Breathing as within-subject factors. Exploratory secondary endpoint.
Experimental visit (single visit, approximately 188 minutes)
Mean Respiratory Rate During the Hyperventilation and Normal-Breathing Blocks
大体时间：Experimental visit (single visit, approximately 188 minutes)
Respiratory rate, reported in breaths per minute, derived from the continuous respiratory-belt and capnography recordings. One value is reported per participant per breathing condition: the mean respiratory rate across the normal-breathing block and across the four guided hyperventilation cycles. Higher values indicate faster breathing; the measure describes the physiological context in which the bodily-self measures were obtained and is not a clinical benefit or harm outcome. Exploratory secondary endpoint, reported descriptively.
Experimental visit (single visit, approximately 188 minutes)
Mean Heart Rate Variability (RMSSD) During the Hyperventilation and Normal-Breathing Blocks
大体时间：Experimental visit (single visit, approximately 188 minutes)
Heart rate variability derived from the continuous electrocardiogram, reported as the root mean square of successive RR-interval differences (RMSSD) in milliseconds. One value is reported per participant per breathing condition: the mean RMSSD across the normal-breathing block and across the four guided hyperventilation cycles. Higher values indicate greater beat-to-beat variability; the measure describes the physiological context in which the bodily-self measures were obtained and is not a clinical benefit or harm outcome. Exploratory secondary endpoint, reported descriptively.
Experimental visit (single visit, approximately 188 minutes)

合作者和调查者

在这里您可以找到参与这项研究的人员和组织。

赞助

University of Fribourg

调查人员

  • 首席研究员：Gregor Hasler, Prof. Dr. med.、University of Fribourg

研究记录日期

这些日期跟踪向 ClinicalTrials.gov 提交研究记录和摘要结果的进度。研究记录和报告的结果由国家医学图书馆 (NLM) 审查，以确保它们在发布到公共网站之前符合特定的质量控制标准。

研究主要日期

学习开始 (估计的)

2026年9月1日

初级完成 (估计的)

2027年7月31日

研究完成 (估计的)

2027年7月31日

研究注册日期

首次提交

2026年7月14日

首先提交符合 QC 标准的

2026年8月12日

首次发布 (实际的)

2026年8月18日

研究记录更新

最后更新发布 (实际的)

2026年8月18日

上次提交的符合 QC 标准的更新

2026年8月12日

最后验证

2026年8月1日

更多信息

与本研究相关的术语

关键字

其他相关的 MeSH 术语

其他研究编号

  • HYPERSELF-2026-01385
  • 2026-01385 (其他标识符：BASEC number - Cantonal Ethics Committee Bern, Switzerland (swissethics))

计划个人参与者数据 (IPD)

计划共享个人参与者数据 (IPD)？

不

IPD 计划说明

Individual participant data are not made publicly available. Only aggregated data (summary statistics, analysis code, and metadata) are shared openly, in line with the study's data-protection commitments and the conditions of the approving ethics committee. Any request for de-identified individual-level data would be assessed case-by-case under a data-use agreement and applicable Swiss data-protection law.

药物和器械信息、研究文件

研究美国 FDA 监管的药品

不

研究美国 FDA 监管的设备产品

不

此信息直接从 clinicaltrials.gov 网站检索，没有任何更改。如果您有任何更改、删除或更新研究详细信息的请求，请联系 register@clinicaltrials.gov. clinicaltrials.gov 上实施更改，我们的网站上也会自动更新.

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