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NCT Number: NCT06825364

Near-InfraRed Spectroscopy of Auricular Stimulation

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.

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Key information

Conditions

Healthy Male and Female Subjects Healthy Volunteer Study

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age of at least 18 years

Exclusion criteria

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

Treatment and study plan

auricular stimulation

Other

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

Primary outcomes

  1. fNIRS response, Lumbar spine vs. thumb auricular points

    Time frame: 10 minutes

    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.

Secondary outcomes

  1. fNIRS response, shoulder vs. thumb auricular points

    Time frame: 10 minutes

    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.

  2. fNIRS response, lumbar spine vs. shoulder auricular points

    Time frame: 10 minutes

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Amy Monroe, MPH, MBA

CONTACT

[email protected]

412-623-6382

Carly Riedmann, MPH

CONTACT

[email protected]

412-623-4147

Sponsors and collaborators

Lead sponsor

University of Pittsburgh

Other

Registry information

Official study title

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

Acronym: NIRAS

Important dates

Study start
2025
Primary completion
2028
Study completion
2028
First posted
Feb 13, 2025
Registry last updated
Feb 18, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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