Acute Effects of Transcutaneous Electrical Nerve Stimulation at Acupoints on Nociceptive Transmission: A Mechanism Study Using Pain-Related Evoked Potentials

November 25, 2025 updated by: China Medical University Hospital

The goal of this clinical trial is to learn if transcutaneous electrical nerve stimulation (TENS) applied to acupoints can modulate pain transmission and cortical processing in healthy adult volunteers. The main questions it aims to answer are:

  • Does TENS at Zhongzhu (SJ3) and Hegu (LI4) change pain-related evoked potentials (PREPs)?
  • Does acupoint electrical stimulation alter nociceptive pathways reflected by PREP waveform modulation?

Researchers will compare PREPs recorded before and after TENS at the two acupoints to see if TENS produces measurable effects on cortical nociceptive responses.

Participants will receive low-frequency TENS applied to Zhongzhu (SJ3) and Hegu (LI4), and undergo PREP assessments before and after the intervention to measure cortical responses to standardized noxious stimuli.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

This study aims to investigate the modulatory effects of transcutaneous electrical nerve stimulation (TENS) applied to acupuncture points on pain transmission and cortical processing in healthy adults. Pain-related evoked potentials (PREPs) will be used as the primary neurophysiological measure to examine changes before and after TENS applied to two clinically recognized analgesic acupoints, Zhongzhu (SJ3) and Hegu (LI4). A within-subject design will be adopted, and participants aged 18 years or older will undergo two experimental sessions in randomized order. Each session will include baseline PREP assessment, a 20-minute low-frequency TENS intervention at the assigned acupoint, and a follow-up PREP measurement. PREP waveform characteristics, including N2 and P2 amplitudes and latencies, will be analyzed to determine whether acupoint stimulation alters nociceptive transmission. Subjective pain reports and adverse responses will also be collected to assess tolerability. The findings of this research are expected to provide insight into the neurophysiological basis of acupuncture analgesia and contribute to the development of more refined acupoint-based electrical therapies.

Study Type

Interventional

Enrollment (Estimated)

35

Phase

  • 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 Contact

Study Contact Backup

Study Locations

  • Taiwan
    • Beitun, Taiwan
      • Taichung, Beitun, Taiwan, Taiwan, 406040
        • Recruiting
        • Department of Physical Therapy of China Medical University
        • Contact:
          • Department of Physical Therapy of China Medical University
          • Phone Number: 04-22053366 Ext.#7301
          • Email: aca70@mail.cmu.edu.tw

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Participants will be healthy adults aged 20 years or older. All participants must meet the inclusion criteria, including the absence of chronic medical conditions, no history of drug allergies or skin disorders, and no current use of medications that could affect study outcomes. To ensure the reliability of the results, participants are required to maintain a regular daily routine and have no history of substance or medication abuse.

Exclusion Criteria:

  • Participants with a history of malignant tumors, hand disorders, implanted cardiac pacemakers, pregnancy, epilepsy, or any other condition that may interfere with the study procedures will be excluded from the study.

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: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: TENS Group
Acupoint TENS Intervention (TENS Group) Participants in this group received low-frequency transcutaneous electrical nerve stimulation (TENS) applied to clinically recognized analgesic acupoints, Zhongzhu (SJ3) and Hegu (LI4). Each participant completed two intervention sessions in a randomized order, with at least 48 hours between sessions. During each session, participants first underwent a baseline assessment of pain-related evoked potentials (PREPs), followed by a 20-minute TENS application delivered through surface electrodes placed directly over the target acupoint. The stimulation parameters included low frequency and low-intensity currents adjusted to a comfortable but perceptible level. Immediately after the stimulation period, participants received a follow-up PREP assessment to evaluate changes in nociceptive cortical processing. Subjective pain responses and any discomfort or adverse reactions were recorded throughout the procedure. The entire protocol was designed to deter
Device: transcutaneous electrical nerve stimulation (TENS)
TENS was applied to the acupoints Zhongzhu (SJ3) and Hegu (LI4) using surface electrodes. Low-frequency electrical currents were delivered at an intensity that was comfortable but perceptible, without causing muscle contraction. Each session lasted 20 minutes, during which participants remained seated and relaxed, and electrode placement and stimulation parameters were monitored for safety and consistency.
Device: EEG machine
EEG signals were recorded using the Neuro-MEP4 system. The device captures cortical electrical activity with high temporal resolution and is suitable for measuring pain-related evoked potentials (PREPs). Standard electrode placement and recording protocols were followed, and signal quality was checked before each session to ensure reliable data collection.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pain-Related Evoked Potentials (PREPs)
Time Frame: Participants were assessed at time points: prior to the intervention (baseline), immediately after TENS application
PREPs were recorded using the Neuro-MEP4 EEG system. Participants were seated comfortably in a quiet room and instructed to remain relaxed during the recordings. Surface electrodes were placed according to standard PREP protocols to capture cortical responses to standardized noxious electrical stimuli applied to the forearm. For each trial, multiple stimuli were delivered, and the resulting N2 and P2 components were averaged to improve signal reliability. The primary outcome measures included the peak amplitudes and latencies of the N2 and P2 waves, which reflect cortical processing of nociceptive input.
Participants were assessed at time points: prior to the intervention (baseline), immediately after TENS application

Collaborators and Investigators

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

Sponsor

China Medical University Hospital

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)

November 25, 2025

Primary Completion (Estimated)

July 1, 2026

Study Completion (Estimated)

July 1, 2026

Study Registration Dates

First Submitted

November 25, 2025

First Submitted That Met QC Criteria

November 25, 2025

First Posted (Actual)

December 5, 2025

Study Record Updates

Last Update Posted (Actual)

December 5, 2025

Last Update Submitted That Met QC Criteria

November 25, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • CMUH114-REC3-149

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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