Tonic Pain and Transauricular Vagal Nerve Stimulation

December 31, 2025 updated by: Laura De Herde, Aalborg University

Exploration of the Effect, and Their Duration, of Different Frequency Transcutaneous Auricular Vagal Nerve Stimulation on Sensory Perception.

This study aims to explore the effect of burst-taVNS (electric stimulation of the concha cymba) on tonic (capsaicin-induced skin pain) and acute (pressure pain sensitivity) experimental pain and cardioception. Primary outcomes include pain intensity. Secondary outcomes include sensory thresholds, resting heart rate (EKG), pupillary measurements and conditioned pain modulation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Across 3 visits, each lasting around 2.5hours, burst-taVNS (electrical stimulation of the concha cymba) will be compared to active-control (electrircal stimulation of the earlobe) and sham (no current) stimulation, two gold-standard controls. Assessments of outcomes will occur before capsaicin application and before, twice during and after electrical ear stimulation.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
36

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • 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

  • Denmark
      • Aalborg, Denmark, 9000
        • Recruiting
        • Center For Neuroplasticity and Pain
        • Contact:

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Child
  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Healthy
  • Speak and understand English
  • 18-60 years old.

Exclusion Criteria:

  • Pregnant and/or breastfeeding
  • Regular use of cannabis, opioids or other drugs
  • Current or previous neurologic, musculoskeletal, mental, or other illnesses (e.g., brain or spinal cord injuries, degenerative neurological disorders, major depression, cardiovascular disease, chronic lung disease, etc.)
  • Current regular (once or more a week) use of analgesic medication or other medication which may affect the trial (including paracetamol and NSAIDs)
  • Recent history of acute pain particularly in the lower limbs
  • Abnormally disrupted sleep in 24 hours preceding experiment
  • Contraindications to electric stimulation application (history of epilepsy, metal implants in head or jaw, etc.)
  • Lack of ability to cooperate
  • Contraindications for capsaicin including an intolerance chili consumption and burns or wounds to the application site.

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: Triple

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: taVNS
Bursts of 25Hz occuring for 3.4sec every 29.4sec for 40min.
Device: taVNS
Two-headed ball-point electrode which is placed in the concha cymba.
Active Comparator: Earlobe Stimulation
Bursts of 25Hz occuring for 3.4sec every 29.4sec for 40min.
Device: Earlobe Stimulation
Circular urface adhering electrodes will be attached to either facet of the earlobe.
Placebo Comparator: Sham
No stimulation.
Device: Sham (No Treatment)
Circular surface adhesive electrodes will be placed on either facet of the earlobe. No current will pass through the electrodes.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Pain Intensity
Time Frame: From when capsaicin is applied to the end of the experiment in 5 min intervals.
Capaisin is a topically administered tonic pain model. Stemming from its chilly-origin, pain induced ressembels heat/light burning sensation which increases within 20minute of application to the forearm, before it plateaus. Associated pain can be stopped immediately by applying ice/cold water. Participants will be asked to rate (using a scale from 0 denoting no pain, to 10 denoting maximal pain) the intensity of the pain in 5 min time intervals.
From when capsaicin is applied to the end of the experiment in 5 min intervals.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Pressure Pain Detection Threshold
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Using the computerized pressure pain algometer tool (Nocitech, Aalborg, Denmark), cuffs placed on the calves of participants wll inflate at a consistent rate. Participants are instructed to rate the pain experiences using a visual analogue scale (VAS) and to press a button when the pain becomes intolerable. The VAS ranges from 0 denoting no pain, to 10 denoting maximal pain. Pain detection, namely the kPa where the VAS is at 1cm, and the pain tolerance, namely the kPa when the deflation-button is pressed, will be acquired.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Conditioned Pain Modulation Effect
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Using the computerized pressure pain algometer tool (Nocitech, Aalborg, Denmark), cuffs placed on the calves of participants wll inflate at a consistent rate. Whilst participants have a constant pressure applied to their non-dominant leg, they are instructed to rate the pain experienced on the dominant leg as the cuff slowly inflates using a visual analogue scale (VAS) and to press a button when the pain becomes intolerable. The VAS ranges from 0 denoting no pain, to 10 denoting maximal pain. Conditioned pain detection, namely the kPa where the VAS is at 1cm, will be acquired.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Pressure Pain Perception
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Trapezius pressure pain perception will be acquired using a handheld pressure algometer (Somedic, Solna, Sweden). Perpendicular to the musle and halfway between the acrominion and the processus spinous vertebrae, the 1cm2 probe will be applied at a constant rate. When particpants first feel pressure pain, they will respond with a button-press.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Pupillary Light Reflex
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Using the Neurolight, per pupil, a 3s light reflex will be acquired. This refers to the reflex following the exposure to a light flash.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Electrocardiography
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Using a 3-lead system (reference electrode on the clavicle, whilst the other two leads reside on the sternum and V4), resting state electrocardiography will be acquired.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
Cardioception Accuracy
Time Frame: Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).
The ability to perceive your heart beats is described as cardioception. One means by which to assess this ability is the 'heartbeat couting task'. Herein, using a queue, participants are tasked to count their heartbeats in 3 undislosed and randomized durations (25, 35 and 35s). This value is then compare to the actual number of beats during each time interval, which is acquired via electrocardiography.
Before Capsaicin application and at 3 time intervals from when the ear stimulation (taVNS, Active Control or Sham) is applied: before, as the stimulation starts and halfway during (at min 20).

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Aalborg University

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 18, 2025

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 16, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 31, 2025

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 8, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
January 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 31, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2025

More Information

Terms related to this study

Keywords

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • N-20230022-5

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

There is only one researcher working on this project. Information will not be shared.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

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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