Tonic Pain and Transauricular Vagal Nerve Stimulation

NCT07325058 | Recruiting

• 1 other identifier: N-20230022-5
• Study Type: interventional
• Target: 36
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Experimental Pain in Healthy Human Subjects

Keywords

cross-over; taVNS

Outcome Measures

Primary Outcomes (1)

• Pain Intensity

  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 Outcomes (6)

• Pressure Pain Detection Threshold

  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

  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

  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

  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

  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).

Study Arms (3)

taVNS

EXPERIMENTAL

Bursts of 25Hz occuring for 3.4sec every 29.4sec for 40min.

Device: taVNS

Earlobe Stimulation

ACTIVE COMPARATOR

Bursts of 25Hz occuring for 3.4sec every 29.4sec for 40min.

Device: Earlobe Stimulation

Sham

PLACEBO COMPARATOR

No stimulation.

Device: Sham (No Treatment)

Interventions

taVNS DEVICE

Two-headed ball-point electrode which is placed in the concha cymba.

taVNS

Earlobe Stimulation DEVICE

Circular urface adhering electrodes will be attached to either facet of the earlobe.

Earlobe Stimulation

Sham (No Treatment) DEVICE

Circular surface adhesive electrodes will be placed on either facet of the earlobe. No current will pass through the electrodes.

Sham

Eligibility Criteria

• Age: 16 Years - 60 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)

You may qualify if:

• Healthy
• Speak and understand English
• years old.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Aalborg University: lead

Study Sites (1)

Center For Neuroplasticity and Pain

Aalborg, 9000, Denmark

RECRUITING

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Masking Details: Electrodes for the different stimulation conditions will be applied during all three visits regardless of which stimulation is active. Wiring of the electrodes is the same but labelled with 'A' or 'B'. Corresponding stimulation condition will not be known to the experimenter (that is also analyzing the data) until after data analysis.
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principle Investigator

Model Details: Burst-taVNS, active-control (electrical stimulation of the earlobe) or sham will be administred to the participant on one of the three visits. Order of stimulation condition will be randomly selected and counter-balanced across participants (minding sex at birth).

Study Record Dates

• First Submitted: December 16, 2025
• First Posted: January 8, 2026
• Study Start: December 18, 2025
• Primary Completion: March 1, 2026
• Study Completion: April 1, 2026
• Last Updated: January 8, 2026

Record last verified: 2025-12

Locations

DK (1)