Electrical Impedance of Acupuncture Meridians: The Relevance of Subcutaneous Collagenous Bands

Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
PLoS ONE (Impact Factor: 3.23). 07/2010; 5(7):e11907. DOI: 10.1371/journal.pone.0011907
Source: PubMed


The scientific basis for acupuncture meridians is unknown. Past studies have suggested that acupuncture meridians are physiologically characterized by low electrical impedance and anatomically associated with connective tissue planes. We are interested in seeing whether acupuncture meridians are associated with lower electrical impedance and whether ultrasound-derived measures--specifically echogenic collagenous bands--can account for these impedance differences.
In 28 healthy subjects, we assessed electrical impedance of skin and underlying subcutaneous connective tissue using a four needle-electrode approach. The impedances were obtained at 10 kHz and 100 kHz frequencies and at three body sites - upper arm (Large Intestine meridian), thigh (Liver), and lower leg (Bladder). Meridian locations were determined by acupuncturists. Ultrasound images were obtained to characterize the anatomical features at each measured site. We found significantly reduced electrical impedance at the Large Intestine meridian compared to adjacent control for both frequencies. No significant decrease in impedance was found at the Liver or Bladder meridian. Greater subcutaneous echogenic densities were significantly associated with reduced impedances in both within-site (meridian vs. adjacent control) and between-site (arm vs. thigh vs. lower leg) analyses. This relationship remained significant in multivariable analyses which also accounted for gender, needle penetration depth, subcutaneous layer thickness, and other ultrasound-derived measures.
Collagenous bands, represented by increased ultrasound echogenicity, are significantly associated with lower electrical impedance and may account for reduced impedances previously reported at acupuncture meridians. This finding may provide important insights into the nature of acupuncture meridians and the relevance of collagen in bioelectrical measurements.

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Available from: Andrew C Ahn, Jul 23, 2014
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    • "However, despite decades of research and a merging of Western and Eastern ideals, an anatomical map of the meridians on the human body has yet to be fully realized [2]. It has been suggested that high electrical conductance, acupuncture sensation patterns, and possible relationships with connective tissue planes could represent meridians or act as identifiers for meridians [3] [4] [5] [6]. However, none of these studies can fully explain the relationships that exist between treatment at each acupoint and the subsequent clinical improvements. "
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    ABSTRACT: The indications of acupoints are thought to be highly associated with the lines of the meridian systems. The present study used data mining methods to analyze the characteristics of the indications of each acupoint and to visualize the relationships between the acupoints and disease sites in the classic Korean medical text Chimgoogyeongheombang . Using a term frequency-inverse document frequency (tf-idf) scheme, the present study extracted valuable data regarding the indications of each acupoint according to the frequency of the cooccurrences of eight Source points and eighteen disease sites. Furthermore, the spatial patterns of the indications of each acupoint on a body map were visualized according to the tf-idf values. Each acupoint along the different meridians exhibited different constellation patterns at various disease sites. Additionally, the spatial patterns of the indications of each acupoint were highly associated with the route of the corresponding meridian. The present findings demonstrate that the indications of each acupoint were primarily associated with the corresponding meridian system. Furthermore, these findings suggest that the routes of the meridians may have clinical implications in terms of identifying the constellations of the indications of acupoints.
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    • "Both scientific definition and anatomical substrate of acupoint remains debatable [7-16]. The correspondence to a dermatome pattern [7], the presence of neurovascular bundles [8,9], different types of terminal nerves [9-11], and a reduced skin electric impedance [12,13] are amongst the most common characteristics attributed to acupoints [14,15]. The material basis of acupuncture is the nerves since the nervous system is the common factor between many scientific evidence on acupuncture’s efficacy [16]. "
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    ABSTRACT: Analysis of the relationship between the nervous system anatomy and the therapeutic characteristics of all acupuncture points in the channel network may provide new insights on the physiological mechanisms underlying acupuncture stimulation for prevention, treatment, and rehabilitation purposes. This study investigates the association between the similarity of acupoints' dermatomes, traditional actions, and contemporary indications. Channel acupoints had their characteristics annotated from a literature review of four topographic atlases of Chinese medicine and one atlas of human anatomy: initials of the channel's name (n = 14), sequential number in the channel (n = 67), acupoint's name (n = 361), dermatomes related to perpendicular needle insertion (n = 31), traditional actions (n = 848), and contemporary indications (n = 1143). Jaccard's similarity coefficient quantified the similarities between dual acupoints. All dual acupoints were evaluated to generate similarity matrices for each nominal variable. Cross-tables were generated by simultaneous classification of variables into levels of similarity with respect to: dermatomes versus traditional actions, dermatomes versus contemporary indications, and traditional actions versus contemporary indications. Goodman-Kruskal gamma and Rousson gamma*2 were calculated based on cross-tables, bootstrap and permutated samples to evaluate the association and determination coefficient between variables, respectively. Significant associations were observed between levels of similarities of dermatomes and traditional actions (gamma = 0.542; P < 0.001), dermatomes and contemporary indications (gamma = 0.657; P < 0.001), and traditional actions and contemporary indications (gamma = 0.716; P < 0.001). Similarities of dermatomes explained 16% of the variance of traditional actions and 25% of contemporary indications. Traditional actions explained 30% of the variance of contemporary indications. The association between traditional actions and contemporary indications was the highest one (gamma = 0.716, 95% confidence interval (95% CI) = [0.715; 0.719]), followed by the association between dermatomes and contemporary indications (gamma = 0.622, 95% CI = [0.621; 0.623]), and between dermatomes and traditional actions (gamma = 0.446, 95% CI = [0.444; 0.447]), all with P < 0.001. The similarity of dermatomes between dual acupoints partially determined the similarity of traditional actions and contemporary indications, therefore dermatomes partially determine the therapeutic efficacy of acupuncture.
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    • "However, it is difficult to evaluate the activation of meridians. Until now, the broad consensus in meridian studies has been the lower impedance along the meridians [2,3]. Usually, the impedance of the skin is proportional to the interstitial fluid volume arising from microcirculation; thus, microcirculation may be an index for meridian activation. "
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