Acute Effects of Transcutaneous Electrical Nerve Stimulation at Acupoints on Nociceptive Transmission

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

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.

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.

Inclusion Criteria:

• Healthy Adult
• 20 years or older
• The absence of chronic medical conditions
• No history of drug allergies
• No skin disorders
• No current use of medications that could affect study outcomes
• Participants maintain a regular daily routine
• No history of substance or medication abuse

Exclusion Criteria:

• History of malignant tumors
• History of hand disorders
• Has implanted cardiac pacemakers
• Pregnancy
• Epilepsy
• Any other condition that may interfere with the study procedures