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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
35
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.
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.
Department of Physical Therapy of China Medical University
Taichung, Beitun, Taiwan, Taiwan
RECRUITINGPain-Related Evoked Potentials (PREPs)
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.
Time frame: Participants were assessed at time points: prior to the intervention (baseline), immediately after TENS application
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