Vestibular Perception Gates Autonomic Responses to Sinusoidal Galvanic Vestibular Stimulation (GVS-HRV)

July 15, 2026 updated by: Al-Farabi Kazakh National University

Effects of Galvanic Vestibular Stimulation on Heart Rate Variability

Brief Summary This randomized, double-blind, sham-controlled clinical trial is designed to investigate whether repeated sinusoidal galvanic vestibular stimulation (GVS) influences cardiac autonomic regulation in healthy adults during their routine occupational activities, and to determine whether these effects depend on subjective vestibular perception (dizziness) experienced during stimulation.

The main questions it aims to answer are:

Does repeated sinusoidal GVS alter heart rate variability (HRV) in healthy adults during their normal work activities?

Do autonomic responses to GVS depend on the subjective intensity of dizziness experienced during stimulation?

Does repeated GVS affect psycho-emotional well-being, including depressive and anxiety symptoms?

Researchers will compare active GVS to sham stimulation to see if active stimulation produces measurable changes in cardiac autonomic regulation and whether these changes differ between participants reporting stronger versus minimal dizziness.

Participants will undergo baseline assessment, complete four consecutive daily sessions of active or sham GVS, and undergo post-intervention assessment. Autonomic responses will be assessed using multiple HRV indices.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Detailed Description

Scientific Background and Rationale Occupational stress is recognized as an important contributor to impaired physical and mental health. Continuous exposure to cognitive workload, emotional demands, and psychosocial stressors may alter autonomic nervous system regulation, resulting in reduced physiological adaptability and increased cardiovascular risk. Heart rate variability (HRV) is one of the most widely accepted non-invasive indicators of autonomic regulation, reflecting the dynamic interaction between sympathetic and parasympathetic branches. Reduced HRV has consistently been associated with impaired stress resilience, diminished vagal regulation, increased cardiovascular morbidity, and adverse mental health outcomes.

Galvanic vestibular stimulation (GVS) applies weak electrical currents through electrodes positioned over the mastoid processes behind the ears. The electrical current activates vestibular afferents, influencing vestibular pathways that project not only to cortical vestibular regions but also to autonomic nuclei within the brainstem. Experimental and neuroanatomical studies have demonstrated direct vestibulo-autonomic connections involving the vestibular nuclei, nucleus tractus solitarius, dorsal motor nucleus of the vagus nerve, and other cardiovascular regulatory centers. Through these pathways, vestibular stimulation may influence autonomic cardiovascular regulation and HRV.

Several laboratory studies have reported that GVS may increase parasympathetic activity, reduce sympathetic influence, and modify cardiovascular reflexes. However, reported autonomic effects vary considerably across studies due to differences in stimulation parameters, waveforms, current intensity, recording conditions, and participant characteristics. Most previous investigations were conducted under highly controlled laboratory conditions, which maximize internal validity but limit ecological validity and clinical translation.

Recent technological advances have facilitated the development of portable GVS systems suitable for ambulatory use. These developments have created opportunities to evaluate vestibular neuromodulation under real-life conditions, where autonomic regulation is continuously challenged by natural fluctuations in cognitive workload, emotional demands, posture, movement, fatigue, and environmental stressors. Despite increasing interest in wearable neuromodulation technologies, the physiological effects of repeated GVS administered during normal occupational activities remain insufficiently investigated.

An additional unresolved question concerns the considerable inter-individual variability in subjective responses to vestibular stimulation. Some individuals experience pronounced sensations of self-motion or dizziness during GVS, whereas others report minimal or no vestibular sensations despite receiving identical stimulation parameters. This variability suggests that autonomic responses may depend not only on the physical characteristics of vestibular stimulation but also on the degree of conscious vestibular perception.

Current concepts of interoception and predictive processing propose that autonomic regulation is dynamically influenced by the brain's interpretation of incoming bodily signals rather than by peripheral sensory input alone. According to these models, physiological responses may be modulated by the subjective significance of sensory information and by prediction errors generated when incoming vestibular information conflicts with visual and proprioceptive signals. Therefore, conscious perception of vestibular stimulation may represent an important determinant of autonomic adaptation.

Detailed Methodology The study was conducted in two occupational settings: rest facilities of Kazakhtelecom JSC and the neurocognitive laboratories of the Brain Institute at Farabi University.

Following enrollment and baseline assessment, participants entered a four-day intervention period with one study visit per day. Each visit followed an identical protocol. Upon arrival, participants were fitted with a Polar H10 chest-mounted heart rate sensor for continuous ambulatory ECG recording. After sensor placement, participants completed the first PANAS assessment. ECG recording continued while participants performed their routine occupational activities. Immediately before stimulation, participants completed a second PANAS assessment. They subsequently received either active or sham GVS while seated comfortably with their eyes closed, listening to standardized meditative music. Immediately following stimulation, participants completed a third PANAS assessment together with a standardized questionnaire evaluating stimulation-related sensations (dizziness, warmth, burning, itching, each rated on a 4-point scale from 0 = "not experienced" to 3 = "strongly experienced"). Approximately one hour after stimulation, the sensor was removed and participants completed the fourth PANAS assessment. On the final intervention day, participants indicated whether they believed they had received active or sham stimulation to evaluate blinding integrity.

One to two days after the intervention course, participants underwent a post-intervention assessment identical to baseline procedures, including ambulatory ECG monitoring and psychometric evaluation.

Heart Rate Variability Assessment Continuous RR interval data were acquired using the Polar H10 sensor. Recordings were exported for offline processing using Kubios HRV Premium software. Artifact correction and interpolation procedures were applied before HRV calculation. HRV indices were calculated for consecutive six-minute epochs according to international recommendations.

Time-domain indices included mean RR intervals and SDNN. Frequency-domain analysis included normalized high-frequency power (HFnu). Low-frequency power was excluded from primary analyses because the stimulation frequency (0.1 Hz) overlapped with the conventional low-frequency HRV band, potentially confounding physiological interpretation. Nonlinear indices included SD1, SD2, the SD2/SD1 ratio, and detrended fluctuation analysis (DFA α1). The Baevsky Stress Index was calculated as an integrative geometric measure of regulatory strain.

HRV was analyzed at three temporal scales: acute (six-minute epochs before, during, and after stimulation), macro-scale (one-hour pre- and post-stimulation recordings), and course-level (baseline versus post-intervention comparisons).

Psychometric Assessment Psycho-emotional functioning was evaluated using standardized self-report questionnaires. The Positive and Negative Affect Schedule (PANAS) was administered repeatedly to assess short-term affective changes. Depressive symptoms were evaluated using the Inventory of Depressive Symptomatology - Self Report (IDS-SR). Anxiety symptoms were assessed using the Generalized Anxiety Disorder 7-item scale (GAD-7). Validated Russian-language versions were used for all questionnaires.

Statistical Analysis Baseline characteristics were compared using parametric or non-parametric tests depending on data distribution. Categorical variables were analyzed using Pearson's chi-square tests.

Psychometric outcomes were analyzed using repeated-measures ANOVA and ANCOVA with baseline adjustment when appropriate. Post hoc comparisons were corrected using Bonferroni adjustment.

Primary autonomic analyses were performed using linear mixed-effects models estimated by restricted maximum likelihood. Separate models were constructed for acute, macro-scale, and cumulative analyses. Mean heart rate was included as a time-varying covariate. Random intercepts were specified for individual participants, and first-order autoregressive covariance structures were applied to model temporal dependence among repeated observations. Model assumptions were evaluated using residual diagnostics. Effect sizes were calculated using partial eta squared (η²p).

Participants were prospectively stratified according to average dizziness ratings using median split classification to create High-Dizziness and Low/No-Dizziness subgroups. Sensitivity analyses evaluated dizziness as a continuous variable to confirm robustness.

Safety Monitoring Participant safety was monitored throughout the intervention. Immediately after each session, participants completed questionnaires documenting stimulation-related sensations. No medications were administered, and no invasive procedures were performed. Participants were free to discontinue their participation at any time without providing a reason. No penalties or consequences were applied for withdrawal, and participants retained the right to withdraw their data upon request.

Scientific Significance This study was designed to extend previous laboratory investigations by evaluating autonomic and psycho-emotional responses to GVS under ecologically valid occupational conditions. By integrating acute, short-term recovery, and cumulative assessments during participants' normal professional activities, the study addresses a gap in the current literature regarding real-world applicability of vestibular neuromodulation. The prospective evaluation of subjective vestibular perception as a potential moderator of autonomic responses represents a conceptual innovation. The findings are expected to contribute to individualized non-invasive neuromodulation approaches and provide additional evidence regarding the physiological safety and tolerability of repeated sinusoidal GVS in healthy adults.

Study Type

Interventional

Enrollment (Actual)

56

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Kazakhstan
      • Almaty, Kazakhstan, 050004
        • JSC "Kazakhtelecom"
      • Almaty, Kazakhstan, 050040
        • Al-Farabi Kazakh National University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Аge between 18 and 49 years
  • Absence of dermatological conditions (e.g., eczema, psoriasis) or open wounds in the electrode placement area (mastoid region)
  • No metallic or electronic implants (e.g., pacemakers, cochlear implants)
  • No history of neurological, psychiatric, or cardiovascular disorders
  • Not currently pregnant
  • Employment or activities not involving the operation of vehicles or hazardous machinery

Exclusion Criteria:

• Failure to meet any of the inclusion criteria

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active GVS
Participants receive active sinusoidal galvanic vestibular stimulation (GVS) using the BrainPatch device. Stimulation parameters: 0.1 Hz sinusoidal waveform, peak current 0.62 mA, delivered for 6 minutes through bilateral electrodes placed over the mastoid processes. Participants remain seated with eyes closed while listening to relaxing meditative music. Stimulation is administered once daily for four consecutive days.
Device: Galvanic Vestibular Stimulation (GVS) using BrainPatch device
Sinusoidal galvanic vestibular stimulation delivered via bilateral mastoid electrodes using the portable BrainPatch device. Stimulation parameters: 0.1 Hz sinusoidal waveform, peak current 0.62 mA, administered for 6 minutes per session with participants seated, eyes closed, and listening to relaxing meditative music.
Other Names:
  • GVS
Sham Comparator: Sham GVS
An identical acoustic environment was created in the Sham group. To ensure effective blinding, participants in the Sham group received only one 10-second stimulation cycle at the beginning of the 6-minute session.
Device: Galvanic Vestibular Stimulation (GVS) using BrainPatch device
Sinusoidal galvanic vestibular stimulation delivered via bilateral mastoid electrodes using the portable BrainPatch device. Stimulation parameters: 0.1 Hz sinusoidal waveform, peak current 0.62 mA, administered for 6 minutes per session with participants seated, eyes closed, and listening to relaxing meditative music.
Other Names:
  • GVS

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Heart Rate Variability (HRV) Indices from Baseline to Post-Course and During Acute Stimulation
Time Frame: • Baseline (Day 1) • Days 2-5 (pre-stimulation, during 6-minute stimulation, immediately post-stimulation, and 1 hour post-stimulation) • Day 6 (post-course assessment)
HRV will be assessed using complementary indices derived from continuous ambulatory ECG recordings (Polar H10) across multiple temporal scales: (1) course-level: baseline vs. post-course comparison; (2) acute: pre-stimulation, during stimulation, and post-stimulation epochs; (3) macro-scale: one-hour pre-stimulation vs. one-hour post-stimulation windows. Indices include time-domain (SDNN, mean RR intervals), frequency-domain (HFnu), nonlinear (SD1, SD2, SD2/SD1 ratio, DFA α1), and geometric (Baevsky Stress Index) measures.
• Baseline (Day 1) • Days 2-5 (pre-stimulation, during 6-minute stimulation, immediately post-stimulation, and 1 hour post-stimulation) • Day 6 (post-course assessment)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Autonomic Responses by Vestibular Perception Subgroups (High vs Low/No Dizziness)
Time Frame: • Baseline (Day 1) • Days 2-5 (pre-stimulation, during 6-minute stimulation, immediately post-stimulation, and 1 hour post-stimulation) • Day 6 (post-course assessment)
Comparison of HRV changes between participants stratified by dizziness intensity (High Dizziness vs Low/No Dizziness) using median split based on average dizziness ratings across intervention days. Outcomes include RR, HFnu, SD1, SD2/SD1 ratio, DFA α1, and Stress Index.
• Baseline (Day 1) • Days 2-5 (pre-stimulation, during 6-minute stimulation, immediately post-stimulation, and 1 hour post-stimulation) • Day 6 (post-course assessment)
Stimulation-Related Sensations and Tolerability
Time Frame: • Days 2-5 (immediately after each stimulation session)
Participants rated the intensity of dizziness, warmth, burning, itching, pain, metallic taste, nausea, discomfort, and fatigue using a 4-point ordinal scale (0 = "not experienced" to 3 = "strongly experienced") immediately after each session. Average dizziness ratings across the four sessions were used to stratify participants into High Dizziness and Low/No Dizziness subgroups for secondary analyses of autonomic responses.
• Days 2-5 (immediately after each stimulation session)
Changes in Psycho-Emotional Well-Being (Depressive Symptoms, Anxiety, and Affect)
Time Frame: • Baseline (Day 1) • Day 6 (post-course assessment)
Assessment of depressive symptom severity using the Inventory of Depressive Symptomatology - Self Report (IDS-SR), anxiety symptoms using the Generalized Anxiety Disorder 7-item scale (GAD-7), and positive and negative affect using the Positive and Negative Affect Schedule (PANAS). The IDS-SR and GAD-7 were administered once at baseline (Day 1) and once at post-course assessment (Day 6). The PANAS was administered at Day 1 (upon arrival and at sensor removal) and Day 6 (upon arrival and at sensor removal).
• Baseline (Day 1) • Day 6 (post-course assessment)
Blinding Integrity Assessment
Time Frame: • Day 5 (immediately after the fourth stimulation session)
Participants were asked to indicate whether they believed they had received active GVS or sham stimulation. The distribution of guesses was compared between the Active GVS and Sham groups using Pearson's chi-square test to evaluate the effectiveness of blinding.
• Day 5 (immediately after the fourth stimulation session)
Change in Positive and Negative Affect as Measured by the PANAS
Time Frame: • Days 2-5 (morning, pre-stimulation, post-stimulation, and end of workday)
The Positive and Negative Affect Schedule (PANAS) is a 20-item self-report questionnaire consisting of two 10-item subscales measuring positive affect (PA) and negative affect (NA). Participants rate the extent to which they have experienced each emotion over the past week on a 5-point Likert scale ranging from 1 (very slightly or not at all) to 5 (extremely). Scores for each subscale range from 10 to 50, with higher scores indicating greater positive or negative affect. The PANAS was administered four times daily during each of the four intervention days (morning, pre-stimulation, post-stimulation, and end of workday).
• Days 2-5 (morning, pre-stimulation, post-stimulation, and end of workday)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Al-Farabi Kazakh National University

Collaborators

Research and Production Center "Comprehensive Equipment"
BrainPatch

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

November 30, 2021

Primary Completion (Actual)

May 13, 2022

Study Completion (Actual)

May 13, 2022

Study Registration Dates

First Submitted

July 9, 2026

First Submitted That Met QC Criteria

July 15, 2026

First Posted (Actual)

July 20, 2026

Study Record Updates

Last Update Posted (Actual)

July 20, 2026

Last Update Submitted That Met QC Criteria

July 15, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • IRB A343
  • BR27198099 (Other Grant/Funding Number: Committee of Science of the Ministry of Science and Higher Education of the Republic of Kazakhstan)
  • IRB-A843 (Other Identifier: Local Ethical Committee of Al-Farabi Kazakh National University)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data that underlie the results reported in this article, including:

Demographic and anthropometric data (age, sex, body mass index) Heart rate variability indices (time-domain: SDNN, mean RR intervals; frequency-domain: HFnu; nonlinear: SD1, SD2, SD2/SD1 ratio, DFA α1; geometric: Baevsky Stress Index) Psychometric questionnaire scores (PANAS, IDS-SR, GAD-7) Stimulation-related sensations ratings (dizziness, warmth, burning, itching) Data dictionaries defining all variables will be provided alongside the datasets.

IPD Sharing Time Frame

De-identified individual participant data and supporting documents will be available beginning 9 months following publication of the main results and ending 5 years after publication.

IPD Sharing Access Criteria

Data and supporting documents will be made available upon reasonable request to the principal investigator. Requests will be reviewed to ensure appropriate use and compliance with ethical standards.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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