Near-InfraRed Spectroscopy of Auricular Stimulation (NIRAS)

Neural Responses to Tactile Auricular Stimulation Measured by Functional Near-infrared Spectroscopy in Pain-free Volunteers

This is a single-visit non-invasive study of healthy volunteer subjects. Brain activity will be measured with infra-red light sensors attached to a cap worn on the head, while both ears are gently stimulated with plastic filaments.

Study Overview

• Status: Recruiting
• Conditions: Healthy Volunteer Study; Healthy Male and Female Subjects
• Intervention / Treatment: Other: auricular stimulation

Detailed Description

The aim of this study is to localize and quantify brain activations from experimental stimulation of auricular points in pain-free volunteers. Investigators will stimulate auricular points for the shoulder, thumb, and lumbar spine with von Frey filaments and measure functional near-infrared spectroscopy (fNIRS) responses in the primary somatosensory (S1) and prefrontal cortex (PFC). This will test the hypothesis that stimulation across different points in the auricular cartography maps to distinct brain responses, an assumption underpinning AT theory. Stimulation of different ear points is anticipated to induce similar PFC responses, but activate distinct areas within the S1 homunculus, validating the concept of auricular cartography.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Amy Monroe, MPH, MBA; Phone Number: 412-623-6382; Email: monroeal@upmc.edu
• Study Contact Backup: Name: Carly Riedmann, MPH; Phone Number: 412-623-4147; Email: riedmannca@upmc.edu

Study Locations

• United States
  • Pennsylvania
    • Pittsburgh, Pennsylvania, United States, 15213
      • Recruiting
      • University of Pittsburgh
      • Contact: Amy Monroe, MPH, MBA; Phone Number: 412-623-6382; Email: monroeal@upmc.edu
      • Contact: Keith Vogt, MD, PhD; Email: vogtkm@upmc.edu

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Age of at least 18 years

Exclusion Criteria:

1. frequent or chronic pain requiring the use of pain-relieving medications more than twice per week, on average, in the last 3 months,
2. history or symptoms of neuropathy,
3. active lesions or skin disruptions to either ear,
4. recent (< 3 mo) illicit drug use,
5. history of substance misuse/abuse,
6. current or recent (<1 month) opioid or marijuana use, and
7. current regular use of psychoactive prescription medications

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Auricular stim with fNIRS; Points on the ear that correspond to the the shoulder, thumb, and lumbar spine (within an accepted cartography for auriculotherapy) will be stimulated repeatedly with flexible plastic (von Frey) filaments. A functional near-infrared spectroscopy cap will be worn, and brain responses to the stimulation will be recorded.	Other: auricular stimulation; Different points on both ears will be repeatedly stimulated with a plastic filament. This will be felt, but not be painful and should not result in lasting irritation.; Other Names: von Frey filament

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fNIRS response, Lumbar spine vs. thumb auricular points	Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the lumbar-spine vs. thumb. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the lumbar point, compared to stimulation of the thumb point; more negative scores mean change with stimulation of the thumb, compared to the lumbar spine. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.	10 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
fNIRS response, shoulder vs. thumb auricular points	Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the shoulder vs. thumb. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the shoulder, compared to stimulation of the thumb point; more negative scores mean change with stimulation of the thumb, compared to the shoulder. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.	10 minutes
fNIRS response, lumbar spine vs. shoulder auricular points	Calculated T-statistic for contrast of analyzed fNIRS signal change, comparing responses from stimulation of the ipsilateral ear at the auricular points corresponding to the lumbar-spine vs. shoulder. A T-statistic of 0 indicates no difference; more positive scores mean stronger fNIRS signal change with stimulation of the lumbar point, compared to stimulation of the shoulder point; more negative scores mean change with stimulation of the shoulder, compared to the lumbar spine. This outcome is a number reflecting the overall magnitude of difference between stimulation points, calculated in one summary statistic. Dispersion measures cannot be calculated for the T-statistic in this analysis framework.	10 minutes

Collaborators and Investigators

• Sponsor: University of Pittsburgh
• Investigators: Principal Investigator: Keith Vogt, MD, PhD, University of Pittsburgh

Study record dates

Study Major Dates

• Study Start (Actual): August 12, 2025
• Primary Completion (Estimated): February 1, 2028
• Study Completion (Estimated): February 1, 2028

Study Registration Dates

• First Submitted: February 7, 2025
• First Submitted That Met QC Criteria: February 7, 2025
• First Posted (Actual): February 13, 2025

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 13, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: functional near infrared spectroscopy; auricular stimulation
• Other Study ID Numbers: STUDY24090032

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: All of the individual participant data collected during the trial will be publicly shared, after deidentification.
• IPD Sharing Time Frame: Individual participant data are anticipated to be available via open-access database within one year of study completion.

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