Transcutaneous Auricular Vagus Nerve Stimulation and Spirometry: Sham-Controlled Randomized Trial

NCT07482930 | Recruiting

• 2 other identifiers: taVNS2BEU-IRB 2026/02-1
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

This study will examine the short-term effects of transcutaneous auricular vagus nerve stimulation (a non-invasive electrical stimulation delivered through the outer ear) on lung function measured by spirometry in healthy adults. The vagus nerve is involved in many automatic body functions, and ear-based stimulation has been used in research to explore its possible effects on different physiological systems. However, it is not clear whether a brief stimulation session can acutely influence breathing test results in people without respiratory disease. Healthy volunteers aged 18-40 will take part in one laboratory visit. Participants will be randomly assigned to one of two groups: (1) active bilateral stimulation applied to specific ear regions that are known to be innervated by the vagus nerve, or (2) sham stimulation using the same device setup but designed to minimize vagal activation. The stimulation session will last approximately 10 minutes. Before and after the stimulation, participants will perform standard spirometry (breathing) tests. Primary spirometric outcomes will include common measures of lung function such as forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and peak expiratory flow (PEF). Heart rate, heart rate variability, and blood pressure may also be recorded to monitor physiological responses and safety during the visit. Participation is voluntary and participants may withdraw at any time. The procedure is considered minimal risk. Possible side effects are usually mild and temporary, such as tingling, warmth, or mild discomfort at the ear. Rarely, participants may feel lightheaded; if this occurs, the procedure will be stopped and the participant will be monitored until symptoms resolve. There is no guaranteed direct benefit to participants. The results may help clarify whether short-term ear-based vagus nerve stimulation can influence spirometric parameters and may inform future studies on autonomic and respiratory interactions.

Conditions

Vagus Nerve Stimulations; Spirometry; Autonomic Nervous System (ANS) Functioning and Mood State; Blood Pressure Monitoring; Respiratory Function Tests

Keywords

transcutaneous auricular vagus nerve stimulation; spirometry; autonomic nervous system; sham stimulation; pulmonary function test; blood pressure

Outcome Measures

Primary Outcomes (3)

• Change in forced expiratory volume in 1 second (FEV1)

  Forced expiratory volume in 1 second (FEV1), reported in liters (L), will be measured immediately before and immediately after the intervention. The outcome will be defined as the pre-to-post change (post minus pre), and between-group differences in change between active stimulation and sham control will be evaluated.\[FVC\], and peak expiratory flow \[PEF\]) will be measured immediately before and immediately after the intervention. The primary endpoint is the pre-to-post change (post minus pre) and the between-group difference in change between active stimulation and sham control.

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in forced vital capacity (FVC)

  Forced vital capacity (FVC), reported in liters (L), will be measured immediately before and immediately after the intervention. The outcome will be defined as the pre-to-post change (post minus pre), and between-group differences in change between active stimulation and sham control will be evaluated.

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in peak expiratory flow (PEF)

  Peak expiratory flow (PEF), reported in liters per minute (L/min), will be measured immediately before and immediately after the intervention. The outcome will be defined as the pre-to-post change (post minus pre), and between-group differences in change between active stimulation and sham control will be evaluated.

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

Secondary Outcomes (8)

• Change in RMSSD from chest recordings

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in SDNN from chest recordings

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in LF power from chest recordings

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in HF power from chest recordings

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

• Change in LF/HF ratio from chest recordings

  Single visit: assessed pre-intervention and immediately post-intervention (within the same session).

Study Arms (2)

Active bilateral auricular vagus nerve stimulation

EXPERIMENTAL

Participants receive active bilateral transcutaneous auricular vagus nerve stimulation using an external stimulator. Electrodes are placed on auricular regions targeted for vagal innervation (bilaterally). Stimulation is applied for approximately 10 minutes with standardized parameters and individually adjusted intensity to a clearly perceptible but non-painful level. Spirometry (e.g., FVC, FEV1, PEF) is performed before and after the session; heart rate, heart rate variability, and blood pressure may also be recorded.

Device: Transcutaneous auricular vagus nerve stimulation

Sham auricular stimulation (control)

SHAM COMPARATOR

Participants receive sham stimulation using the same device appearance and session structure. Electrodes are placed on an ear location intended to minimize vagal activation (e.g., ear lobule), and stimulation is delivered at a minimal/low level to mimic sensation without therapeutic stimulation. The same pre- and post-session spirometry and physiological measurements are collected as in the active arm.

Device: Sham transcutaneous auricular stimulation

Interventions

Transcutaneous auricular vagus nerve stimulation DEVICE

Transcutaneous auricular vagus nerve stimulation is delivered bilaterally using an external stimulator with electrodes placed on auricular regions targeted for vagal innervation (e.g., cymba conchae). Stimulation is applied for approximately 10 minutes. Parameters are standardized (e.g., 25 Hz; pulse width 200-300 microseconds), and current intensity is individually adjusted to a clearly perceptible but non-painful level. The procedure is performed in a single visit with pre- and post-intervention spirometry and physiological monitoring as specified in the protocol.

Active bilateral auricular vagus nerve stimulation

Sham transcutaneous auricular stimulation DEVICE

Sham stimulation uses the same device, setup, and session duration to mimic the active procedure. Electrodes are placed on an ear location intended to minimize vagal activation (e.g., ear lobule), and stimulation is delivered at a minimal/low level to provide a similar sensation without therapeutic vagal stimulation. Pre- and post-session spirometry and other measurements are collected identically to the active arm.

Sham auricular stimulation (control)

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Aged 18-40 years.
• Healthy volunteers.
• Able to perform spirometry and follow study instructions.
• Provided written informed consent.

You may not qualify if:

• Any cardiovascular disease, cardiac arrhythmia, hypertension, or related condition.
• Any neurological disorder (e.g., diabetes mellitus, peripheral neuropathy, epilepsy).
• Any diagnosed psychiatric disorder.
• Any respiratory disease (e.g., asthma, chronic obstructive pulmonary disease).
• Pregnancy or suspected pregnancy.
• Ear conditions that prevent stimulation (infection, open wound, pain/tenderness) or presence of a piercing at/near the stimulation site.
• Vigorous exercise within 24 hours prior to measurement.
• Caffeine intake, smoking, or alcohol consumption within 4-6 hours prior to measurement.
• Marked intolerance or hypersensitivity to the device or the procedure.
• Inability to follow instructions during measurements or refusal to complete the session.

Sponsors & Collaborators

• SEFA HAKTAN HATIK: lead
• Sinop University: collaborator

Study Sites (1)

Güzelyurt Neighborhood, Mustafa Bozkurt Street, No: 9, 57900, Türkeli, Sinop, Türkiye

Sinop, 57900, Turkey (Türkiye)

RECRUITING

Related Publications (8)

• Paleczny B, Seredynski R, Ponikowska B. Inspiratory- and expiratory-gated transcutaneous vagus nerve stimulation have different effects on heart rate in healthy subjects: preliminary results. Clin Auton Res. 2021 Apr;31(2):205-214. doi: 10.1007/s10286-019-00604-0. Epub 2019 Apr 2.

  PMID: 30941526 BACKGROUND

• Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet. 1986 Feb 8;1(8476):307-10.

  PMID: 2868172 BACKGROUND

• Shrout PE, Fleiss JL. Intraclass correlations: uses in assessing rater reliability. Psychol Bull. 1979 Mar;86(2):420-8. doi: 10.1037//0033-2909.86.2.420.

  PMID: 18839484 BACKGROUND

• Koo TK, Li MY. A Guideline of Selecting and Reporting Intraclass Correlation Coefficients for Reliability Research. J Chiropr Med. 2016 Jun;15(2):155-63. doi: 10.1016/j.jcm.2016.02.012. Epub 2016 Mar 31.

  PMID: 27330520 BACKGROUND

• Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Circulation. 1996 Mar 1;93(5):1043-65. No abstract available.

  PMID: 8598068 BACKGROUND

• Kim AY, Marduy A, de Melo PS, Gianlorenco AC, Kim CK, Choi H, Song JJ, Fregni F. Safety of transcutaneous auricular vagus nerve stimulation (taVNS): a systematic review and meta-analysis. Sci Rep. 2022 Dec 21;12(1):22055. doi: 10.1038/s41598-022-25864-1.

  PMID: 36543841 BACKGROUND

• Wang L, Wang Y, Wang Y, Wang F, Zhang J, Li S, Wu M, Li L, Rong P. Transcutaneous auricular vagus nerve stimulators: a review of past, present, and future devices. Expert Rev Med Devices. 2022 Jan;19(1):43-61. doi: 10.1080/17434440.2022.2020095. Epub 2022 Jan 13.

  PMID: 34937487 BACKGROUND

• Zou N, Zhou Q, Zhang Y, Xin C, Wang Y, Claire-Marie R, Rong P, Gao G, Li S. Transcutaneous auricular vagus nerve stimulation as a novel therapy connecting the central and peripheral systems: a review. Int J Surg. 2024 Aug 1;110(8):4993-5006. doi: 10.1097/JS9.0000000000001592.

  PMID: 38729100 BACKGROUND

Central Study Contacts

SEFA HAKTAN HATIK, MSc, PhD

CONTACT

+90 368 271 55 28; haktanhtk@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: Participants and outcome assessors are blinded to group assignment. Active and sham procedures use the same device appearance and session structure; sham stimulation is delivered using an alternative ear placement intended to minimize vagal activation while maintaining a similar sensory experience. Group allocation is coded, and spirometry and other outcome data are recorded/analyzed using these codes until primary analyses are completed.
• Purpose: OTHER
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Parallel-group, sham-controlled, randomized, single-blind trial. Healthy volunteers are randomly assigned to either active bilateral transcutaneous auricular vagus nerve stimulation or a sham stimulation condition. Spirometric outcomes (e.g., FVC, FEV1, PEF) are measured pre- and post-intervention within a single visit, and between-group differences in change scores are compared.

Study Record Dates

• First Submitted: February 22, 2026
• First Posted: March 19, 2026
• Study Start: March 17, 2026
• Primary Completion: April 20, 2026
• Study Completion: April 25, 2026
• Last Updated: March 19, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)