ABSTRACT Various researches have shown that the locations around acupoints have distinct physical/biochemical properties. However, there have been no simple, reliable and repeatable methods to demonstrate if such distinct properties of acupoints can be quantified and classified according to different physiological/pathological conditions. We proposed a new approach to characterize acupoints using electrical field dispersion, and tested this method on acupoints that are related to menstrual cycle and dysmenorrhea. Methods: Thirty-three (33) primary dysmenorrhea subjects and 25 normal subjects with similar demographic backgrounds were enrolled and tested in the study. For dysmenorrhea subjects (group A) and most of the normal subjects (23, group B), their test was on the 28th day from the beginning of their last menstrual cycle; for a subset of the normal subjects (10, group C), the test day was chosen at 3-5 days after the end of last menstrual cycle. For dysmenorrhea subjects (group A) and most of the normal subjects (23, group B), their test was on the 28th day from the beginning of their last menstrual cycle; for a subset of the normal subjects (10, group C), the test day was chosen at 3-5 days after the end of last menstrual cycle. Quantitative Assessment of Acupoint Status Changes Associated with Menstruation and Dysmenorrhea Using Electrical Field Dispersion Yanjun Wang1, Jiang Ding2, Jie Xia2, 1Hebei Traditional Chinese Medicine University, China, 2AcuMedical, Inc. METHODS Electrical field generation: When a voltage is applied at two electrodes placed on (or beneath) the skin, electrical current flows between the electrodes via different tissue routes, forming a regional electrical field. Voltage distributions in this field are in part dependent on the electrophysical properties of the underlying tissue. By using Field Dispersion Index (FDI), any acupoint within the effective range of the field can be monitored for distinct changes in its electrophysical properties. The FDI is defined as the voltage measured at a target (acupoint) location, normalized by the voltage at the field source, and subtracted by a constant offset. Test Study Design: Thirty-three (33) primary dysmenorrhea subjects and 25 normal subjects with similar demographic backgrounds were enrolled in the study. For dysmenorrhea subjects (Group A) and most of the normal subjects (23, Group B), their test was on the 28th day from the beginning of their last menstrual cycle. For a subset of the normal subjects (10, Group C), the test day was chosen at 3-5 days after the end of last menstrual cycle. Six (6) target acupoints, Sanyinjiao (SP6) (both right and left), Guilai (ST29) (both right and left), Guanyuan (CV4), and Zhongwan (CV12), were selected based on their dysmenorrhea therapy. Once acupuncture needles were inserted into all the target acupoints, they were immediately connected to a special research device, AcuRangerTM, (Acumedical Inc, MN). The device employed low-intensity, non-perceptive alternating voltage to generate micro electrical field near right side Zusanli (ST36) and Diji (SP8). Then it measured voltage drop at each target acupoint, and calculated the corresponding FDI. The entire data acquisition was completed within 1-2 minutes from the needle insertion for each subject. RESULTS STUDY LIMITATIONS Results: Right side Sanyinjiao (SP6) was within the effective range of the measurement field. FDIs at this acupoint showed differences in the three study groups. Comparing among the three groups, the differences were significant (p<0.05) only between Group A and Group C. FDIs are different among groups Comparison between study groups: Multiple comparisons were made between study groups based on the two differentiating factors (pathology and physiology), from which the study groups were formed. The independent-sample T-test results showed that there were no significant differences (in the average FDIs at SP6) between Groups A and B (Table 2), or between Groups B and C (Table 3). However, the differences between Group A and C was significant (Table 4). Due to difficulty in recruiting normal subjects, this study had small sample size especially in Group C and Group B subjects. This may have hindered the significance in comparing among the study groups. Had the sample size increased, or had we created another study group (dysmenorrhea subjects after the end of a menstrual cycle), it would have been more likely to determine a dominating contributing factor of FDI. The success in acquiring FDI readings depends on careful placement of the source electrodes that generate the field. In this study, the field was chosen to be at the vicinity of right side SP6, which was located about 1.5 times the space between the two source electrodes. This location was estimated to be in the beginning of the far-field, and its FDI was sensitive and reflective to physiological/pathological condition changes as stated throughout this paper. Other selected acupoints were located farther away (>6 times the space between the two source electrodes), and the readings of the FDIs at these locations are insensitive to subjects’ conditions. Therefore, further studies or lab simulations are needed to determine the effective range of the field power. The FDI calculations require the assessment of the maximum voltage at the source. Due to tissue-electrode interactions, it was not possible to obtain the true maximum, and only an approximated value could be measured. This would introduce a small amount of error in the FDI calculations. Finally, the FDI reflects only the electrophysical property changes in acupoints. In reality, it is possible that some human physiological/pathological condition changes may be associated with other types of changes in acupoints, such as thermal, sound reflection/absorption ratio, etc. Therefore, the FDI may not be regarded as an inclusive indicator for all the human health conditions. INTRODUCTION According to ancient theory of traditional Chinese medicine (TCM), human body presses a complex and invisible network (called the Meridian) that stretches out the whole body and links each internal organ through various paths. The Meridian performs an important function of maintaining the balance of the internal organ functions by regulating the transportation of energy components along specific paths and at specific time. It is believed that diseases arise from malfunction (e.g blockage) of certain Meridian paths, and the practices of TCM are to re-open the blocked passage and to re-balance the Meridian. One of the most promising TCM therapy modality is acupuncture. It intervenes the Meridian system by stimulating specific acupoints that are the external interface of the Meridian. Huge success of acupuncture in treating a variety of diseases has led to a large increase in the research of the Meridian network and acupoints. Many reports have shown that the locations around acupoints have distinct physical/biochemical properties. However, there have been no simple, reliable and repeatable methods to demonstrate if such distinct properties of acupoints can be quantified and classified according to different physiological/pathological conditions. We proposed a new approach to characterize acupoints using the well-known phenomena of electrical field distribution, and tested this method on selected acupoints that are related to menstrual cycle and dysmenorrhea. FDI ranges among the study groups: Right side Sanyinjiao (SP6) was within the effective range of the measurement field. As shown in Table 1, for Group A, the FDIs ranged between 0.19 and 19.7. More than half (63%) of the subjects in this group had FDIs >5. Similarly, Group B subjects had their FDIs ranging from 0.89 to 21.97, and 55% of them had larger FDIs over 5. In contrast, Group C subjects’ FDIs are less scattered (1.63-10.2), and only a small portion (20%) of FDIs were above 5. The distributions of the FDIs are also shown in Fig 2. Table 2. Average SP6 FDIs in group A vs. Group B Group A（n=30） Group B (n=20) T-value P-value 6.970±4.681 7.240±6.230 -0.175 0.862 Table 3. Average SP6 FDIs in group B vs. Group C Group B（n=20） Group C (n=10) T-value P-value 7.240±6.230 4.005±2.609 1.998 0.056 CONCLUSIONS Physiological/pathological condition changes associated with menstruation are correlated with changes in Sanyinjiao(SP6) electrophysical properties as reflected by the newly defined field dispersion index (FDI). Future studies are warranted to determine if this new index can identify and differentiate more contributing factors, including intervention by acupuncture that could cause changes in SP6 electrophysical properties.   (Note: this report reflects partial results an on-going study. More results will be available on separate paper(s) upon the completion of the study.) Table 3. Average SP6 FDIs in group B vs. Group C Group A （n=30） Group C (n=10) T-value P-value 6.970±4.681 4.005±2.609 2.496 0.019 Figure 2. Distributions of Sanyinjiao (SP6) FDIs of the three study groups. Each point represents the FDI value from one subject.