Electrophysiological assessment of acupuncture points

Objective: This study was designed to assess the occurrence of end plate noise (EPN) in an acupuncture point (AcP). Design: Ten male and 10 female normal volunteers were included in this study. For each subject, mapping of the distribution of EPN loci in an AcP region of Stomach-36 in one leg selected randomly, and also in a nearby non-AcP region in the other leg as a control, was performed with electromyographic recordings. Results: There were significantly more EPN loci in the AcP region of Stomach-36 than in the non-AcP region near this AcP. Whenever the searching needle approached an EPN locus, the subjects always felt pain, soreness, or an unpleasant sensation. This feeling was rarely reported when no EPN was recorded from any site in either an AcP region or a non-AcP region. After electromyographic study, every AcP was confirmed as a myofascial trigger point. Conclusions: Similar to the distribution of EPN loci in an MTrP region, significantly more EPN loci can be identified in an AcP region of Stomach-36 than in a nearby non-AcP site. This study provides additional support to the hypothesis that some AcPs are also myofascial trigger points.