Different Frequency Applications of Transcutaneous Auricular Vagus Nerve Stimulation in Healthy Individuals (taVNS-FREQ)

April 13, 2026 updated by: SEFA HAKTAN HATIK, Sinop University

Investigation of the Acute Effects of Different Frequency Applications of Transcutaneous Auricular Vagus Nerve Stimulation on Autonomic Physiological Responses in Healthy Individuals

This randomized, participant-blinded, sham-controlled crossover study aims to investigate the acute effects of different frequency applications of transcutaneous auricular vagus nerve stimulation (taVNS) on autonomic physiological responses in healthy adults. Participants will receive sham (0 Hz), 10 Hz, 25 Hz, 50 Hz, and 100 Hz taVNS in separate sessions with washout periods between visits. Heart rate variability, blood pressure, pulse rate, respiratory rate, and subjective discomfort will be assessed before and after each intervention session.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The vagus nerve is a major regulator of the parasympathetic branch of the autonomic nervous system. Transcutaneous auricular vagus nerve stimulation (taVNS) is a non-invasive neuromodulation technique applied to auricular regions innervated by the auricular branch of the vagus nerve. Although taVNS has been reported to modulate autonomic function, the acute physiological effects of different stimulation frequencies remain insufficiently characterized.

This study is designed as a randomized, participant-blinded, sham-controlled crossover trial in healthy adults aged 18 to 40 years. Each participant will undergo five intervention conditions in randomized order: sham (0 Hz), 10 Hz, 25 Hz, 50 Hz, and 100 Hz taVNS. Sessions will be separated by 48 to 72 hours to minimize carryover effects. Each stimulation session will last 10 minutes.

Primary autonomic outcomes will be derived from heart rate variability parameters obtained using a Polar H10 chest strap and analyzed with Kubios HRV software. Secondary physiological outcomes will include systolic and diastolic blood pressure, pulse rate, respiratory rate, and subjective discomfort measured using a visual analog scale. The study aims to identify frequency-specific autonomic response profiles and to evaluate whether respiratory rate influences heart rate variability changes associated with taVNS.

Study Type

Interventional

Enrollment (Estimated)

36

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 Contact

Study Locations

  • Turkey (Türkiye)
      • Artvin, Turkey (Türkiye)
        • Artvin Coruh University, Artvin Vocational School, Disabled Care and Rehabilitation Laboratory
        • Contact:
        • Sub-Investigator:
          • Ömer Dicle Kızıl, PT, MSc

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:

  • Healthy adults aged 18 to 40 years
  • No known neurological, cardiovascular, respiratory, or metabolic disease
  • Able to understand study procedures and provide written informed consent
  • No active infection, open wound, or dermatological lesion in the ear region that would interfere with taVNS application
  • Willing and able to attend all study visits

Exclusion Criteria:

  • History of cardiac arrhythmia, pacemaker, or any implanted electronic medical device History of hypertension, diabetes, chronic pulmonary disease, epilepsy, or systemic disease affecting autonomic nervous system function
  • Regular use of medications that may affect autonomic function (e.g., beta-blockers, antidepressants, antiarrhythmics)
  • Intense physical exercise within the previous 24 hours
  • High caffeine or alcohol intake within 12 hours prior to assessment
  • Active smoking on the assessment day
  • Pregnancy or suspected pregnancy
  • Severe discomfort during stimulation (VAS >= 7), dizziness, nausea, or unwillingness to continue
  • Any condition judged by the investigators to make participation unsuitable'

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: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: Sham taVNS
Participants receive sham stimulation during one study session.
Device: Sham taVNS
Sham stimulation is delivered under conditions similar to active taVNS without meaningful vagal stimulation.
Experimental: taVNS 10 Hz
Participants receive active transcutaneous auricular vagus nerve stimulation at 10 Hz during one study session.
Device: taVNS 10 Hz
Active transcutaneous auricular vagus nerve stimulation applied for 10 minutes at 10 Hz.
Experimental: taVNS 25 Hz
Participants receive active transcutaneous auricular vagus nerve stimulation at 25 Hz during one study session.
Device: taVNS 25 Hz
Active transcutaneous auricular vagus nerve stimulation applied for 10 minutes at 25 Hz.
Experimental: taVNS 50 Hz
Participants receive active transcutaneous auricular vagus nerve stimulation at 50 Hz during one study session.
Device: taVNS 50 Hz
Active transcutaneous auricular vagus nerve stimulation applied for 10 minutes at 50 Hz.
Experimental: taVNS 100 Hz
Participants receive active transcutaneous auricular vagus nerve stimulation at 100 Hz during one study session.
Device: taVNS 100 Hz
Active transcutaneous auricular vagus nerve stimulation applied for 10 minutes at 100 Hz.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Root Mean Square of Successive Differences (RMSSD)
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in the root mean square of successive differences (RMSSD) from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in High-Frequency Heart Rate Variability (HF-HRV)
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in high-frequency heart rate variability (HF-HRV) from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Standard Deviation of Normal-to-Normal RR Intervals (SDNN)
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in the standard deviation of normal-to-normal RR intervals (SDNN) from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Low-Frequency (LF) Power
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in low-frequency (LF) power of heart rate variability from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in LF/HF Ratio
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in the ratio of low-frequency to high-frequency heart rate variability (LF/HF ratio) from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Systolic Blood Pressure
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in systolic blood pressure from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Diastolic Blood Pressure
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in diastolic blood pressure from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Pulse Rate
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in pulse rate from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Respiratory Rate
Time Frame: Immediately before and immediately after each 10-minute intervention session
Change in respiratory rate from pre-intervention to post-intervention under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session
Change in Subjective Discomfort Assessed by Visual Analog Scale (VAS)
Time Frame: Immediately before and immediately after each 10-minute intervention session
Subjective discomfort will be assessed using a Visual Analog Scale (VAS) ranging from 0 to 10, where 0 indicates no discomfort and 10 indicates the worst possible discomfort. Higher scores indicate greater discomfort. Change in VAS score from pre-intervention to post-intervention will be evaluated under each stimulation condition.
Immediately before and immediately after each 10-minute intervention session

Collaborators and Investigators

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

Sponsor

Sinop University

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

  • Shaffer F, Ginsberg JP. An overview of heart rate variability metrics and norms. Frontiers in Public Health. 2017;5:258. doi:10.3389/fpubh.2017.00258
  • Yakunina N, Kim SS, Nam EC. Optimization of transcutaneous vagus nerve stimulation using functional MRI. Neuromodulation. 2017;20(3):290-300. doi:10.1111/ner.12541
  • Peuker ET, Filler TJ. The nerve supply of the human auricle. Clinical Anatomy. 2002;15(1):35-37. doi:10.1002/ca.1089
  • Frangos E, Ellrich J, Komisaruk BR. Non-invasive access to the vagus nerve central projections via electrical stimulation of the external ear. Brain Stimulation. 2015;8(3):624-636. doi:10.1016/j.brs.2014.11.018

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 (Estimated)

May 1, 2026

Primary Completion (Estimated)

May 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

April 6, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 13, 2026

Study Record Updates

Last Update Posted (Actual)

April 16, 2026

Last Update Submitted That Met QC Criteria

April 13, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • TAVNS4

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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