How Does the Type of Waveform Affect Tolerability With Transcutaneous Auricular Vagus Nerve Stimulation?

The purpose of this research study is to investigate the effects of different forms of a gentle form of electrical stimulation applied to the ear, known as transcutaneous auricular vagus nerve stimulation (taVNS). The research team is interested in how the different forms affect comfort and tolerability, as well as how well it works.

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Device: Biphasic transcutaneous auricular vagus nerve stimulation; Device: Monophasic transcutaneous auricular vagus nerve stimulation

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Coral Gables, Florida, United States, 33146
      • University of Miami, Plumer Building

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. between the ages of 18-80 years
2. English speaking (must be able to consent and complete the interviews in English)

Exclusion Criteria:

1. chronic pain (average intensity >2/10 on 0-10 scale, for longer than 3 months)
2. acute pain of intensity greater than 3/10
3. chronic inflammatory conditions that are poorly controlled (e.g., diabetes, autoimmune disease)
4. any unstable medical condition or medical contraindication to moderate physical exertion (e.g., unstable angina or cardiac arrythmia)
5. pregnancy
6. currently taking Buprenorphine or recently stopped taking (within 1 month)
7. presence of cognitive impairment or language barrier that impairs full autonomy in the consent process or in the ability to participate in detailed interviews
8. implants in the head or neck, cochlear implants, or pacemaker
9. head or neck metastasis or recent ear trauma
10. history of epilepsy
11. history of autonomic nervous system dysfunction (e.g., postural orthostatic tachycardia syndrome).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Biphasic followed by monophasic taVNS group; Participants in the group "Biphasic followed by monophasic taVNS" will be in this group for up to 6 hours.	Device: Biphasic transcutaneous auricular vagus nerve stimulation; Transauricular vagus nerve stimulation (taVNS) is a simple technique in which small surface electrodes are placed over the skin of the ear that are thought to be innervated by the auricular branch of the vagus nerve (ABVN). Participants in this group will first receive taVNS with a biphasic current, continuous at 25 Hz, for 1 hour, in-person.; Device: Monophasic transcutaneous auricular vagus nerve stimulation; Transauricular vagus nerve stimulation (taVNS) is a simple technique in which small surface electrodes are placed over the skin of the ear that are thought to be innervated by the auricular branch of the vagus nerve (ABVN). Participants in this group will first receive taVNS with a monophasic current, with a 50% duty cycle at 25 Hz, for 1-hour, in-person.
Active Comparator: Monophasic followed by biphasic taVNS group; Participants in the group "monophasic followed by biphasic" will be in this group for up to 6 hours.	Device: Biphasic transcutaneous auricular vagus nerve stimulation; Transauricular vagus nerve stimulation (taVNS) is a simple technique in which small surface electrodes are placed over the skin of the ear that are thought to be innervated by the auricular branch of the vagus nerve (ABVN). Participants in this group will first receive taVNS with a biphasic current, continuous at 25 Hz, for 1 hour, in-person.; Device: Monophasic transcutaneous auricular vagus nerve stimulation; Transauricular vagus nerve stimulation (taVNS) is a simple technique in which small surface electrodes are placed over the skin of the ear that are thought to be innervated by the auricular branch of the vagus nerve (ABVN). Participants in this group will first receive taVNS with a monophasic current, with a 50% duty cycle at 25 Hz, for 1-hour, in-person.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tolerability Measured by Tolerability Questionnaire	Tolerability will be assessed with a questionnaire with scores ranging from 0 (no discomfort) to 10 (worst pain imaginable) for comfort.	Up to 3 hours
Tolerability Measured by Self Report	Tolerability will be assessed by self-report using semi-structured interviews conducted at the end of each study visit. Participants will report whether they experienced mild pain during each transcutaneous auricular vagus nerve stimulation (taVNS) protocol. The outcome measure is the count of participants who reported mild pain, as collected during interviews conducted at the end of each visit.	Up to 3 hours

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Heart Rate Variability (HRV)	Heart rate variability (HRV) will be measured using an H10 chest strap device and expressed in milliseconds. Values after stimulation will be subtracted from baseline values; thus, a positive number will indicate an increase in HRV post taVNS.	Baseline and up to 3 hours

Collaborators and Investigators

• Sponsor: University of Miami
• Investigators: Principal Investigator: Marlon Wong, PT, PhD, University of Miami

Study record dates

Study Major Dates

• Study Start (Actual): December 15, 2024
• Primary Completion (Actual): June 7, 2025
• Study Completion (Actual): June 7, 2025

Study Registration Dates

• First Submitted: September 23, 2024
• First Submitted That Met QC Criteria: September 24, 2024
• First Posted (Actual): September 26, 2024

Study Record Updates

• Last Update Posted (Actual): May 28, 2026
• Last Update Submitted That Met QC Criteria: April 30, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Other Study ID Numbers: 20240796

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: Yes
• product manufactured in and exported from the U.S.: Yes