Electrical impedance along connective tissue planes associated with acupuncture meridians

Connecting the dots: alterations in bioelectric activity at acupuncture Ting (Jing-Well) points following CV4 cranial manipulation

CONTEXT

The mechanisms by which osteopathic cranial manipulative medicine (OCMM) promotes health and healing have yet to be fully elucidated. One commonly utilized OCMM technique, compression of the fourth ventricle (CV4), has been theorized to balance autonomic nervous system (ANS) activity. There is growing evidence that the ANS also plays a significant mechanistic role in acupuncture. Potential connections between OCMM and acupuncture meridian theory largely remain unknown.

OBJECTIVES

By measuring specific electrical parameters at acupuncture points that have been shown to correlate with ANS activity, the objectives of this study were to: 1) determine if CV4 has any influence on the bioelectric properties of the acupuncture meridian system; and 2) determine if CV4 affects the ANS.

METHODS

A total of 77 males and females ages 18-78 years, all volunteers recruited by local flyers and personal or phone contact, were randomized into CV4 (n=40) and Sham (n=37) groups. All CV4 participants were treated by the same physician utilizing standard CV4 protocol. The Sham treatment, performed by a different physician, consisted of the supine participant's occiput resting passively on the physician's finger pads for a similar duration as those in the CV4 group. Among several devices developed to assess ANS activity at acupuncture points, evidence suggests that the Apparatus for Meridian Identification (AMI) is the most accurate and valid. Utilizing the AMI, bioelectric skin parameters were measured immediately before and after CV4 or Sham treatments. Student's or Welch's t tests and Wilcoxon tests were utilized for analysis of normally and non-normally distributed data, respectively.

RESULTS

Statistical significance was determined with a p value less than 0.05. Sham treatments showed insignificant (p=0.754) before vs. after differences in ANS activity measured at acupuncture points, whereas CV4 treatment significantly (p=0.00015) affected ANS activity.

CONCLUSIONS

This research suggests that CV4 has demonstrable biophysical effects on the acupuncture meridian system occurring via the ANS, and that the underlying mechanisms of OCMM and acupuncture may be related. Further studies are needed to clarify this.

Biopotential changes of acupuncture points by acupuncture stimulation

Background

The energy flow at acupuncture point is important for understanding the mechanism of acupuncture treatment. However, there are few studies on energy at acupuncture point, and related studies have limitation in explaining the energy flow in all meridians. Thus, we aimed to understand the properties of electrical energy at acupuncture point in twelve meridians by measuring the biopotential at acupuncture and non-acupuncture points.

Methods

For each meridian, twenty subjects were participated, and biopotential was measured at five transport points and their adjacent non-acupuncture points. In each subject, both ‘non-stimulation’ and ‘stimulation’ experiments were conducted in random order. The data were analyzed in two parts: biopotential variability and biopotential difference between acupuncture and non-acupuncture points.

Results

The biopotential variability at acupuncture point was increased by acupuncture stimulation, and it was related to the activation of Qi flow by acupuncture stimulation. The biopotential difference between acupuncture and non-acupuncture points was formed in the direction related to the Qi flow theory, and this biopotential difference tended to decrease by acupuncture stimulation.

Conclusion

The study on biopotential can provide a foundation for research on energy flow mechanism of acupuncture stimulation, and it is expected to overcome limitation of qualitative explanation in traditional medicine.

Microscopy of Structures Surrounding Typical Acupoints Used in Clinical Practice and Electron Microscopic Evaluation of Acupuncture Needles

Background and objectives Although the general functionality and structures of acupoints have been studied, there has been little insight into their underlying morphology and physical characteristics. We describe the microanatomical structures surrounding acupoints, the electron microscopic appearance of the needles, and the physical effects of acupuncture needling on the fascia. We injected heparinized blood solution through thin needles at seven known and commonly used "sweat acupoints" in eight fresh, unembalmed, cryopreserved human cadavers to mark the needle positions, and later, during histological examination, to identify them. After the solution was injected, samples were dissected and prepared for histological examination. We examined 350 cross-sections of five different paraffin wax sections from each acupoint microscopically. Acupuncture needles were photographed and superimposed on the cross-sectioned tissues at similar magnifications. Needles were also examined under a scanning electron microscope to judge the roughness or smoothness of their surfaces. A greater conglomeration of nerve endings surrounded the acupoints than in tissues more than 1-3 cm distant from them. Nerve endings and blood vessels were in close contact with a complex network of membranes formed by interlacing collagen fibers, and were always enclosed within those collagen membranes. Nerve endings were found within hypodermis, muscles, or both. Scanning electron microscopy demonstrated the three-dimensional shapes and sizes of the needles, and the degree of roughness or smoothness of their polished external surfaces. We demonstrate a delicate arrangement of nerve endings and blood vessels enclosed within complex collagen membrane networks at acupoints within the hypodermis and muscle. This arrangement could explain why needling is an essential step in the acupuncture process that provides favorable outcomes in clinical practice.

Application of fuzzy neural network model and current-voltage analysis of biologically active points for prediction post-surgery risks

The work investigates neural network model for prediction of post-surgical treatment risks. The descriptors of the risk classifiers are formed on the basis of the analysis of the current-voltage characteristics of one, two and three biologically active points. The training and verification samples were formed by examining 120 patients with a diagnosis of benign prostatic hyperplasia. Of these, 62 patients were successfully operated on (class C1), 30 had various complications after surgery (class C2), 28 patients required additional treatment (class C3). The constructed classifiers showed a high quality of predicting critical conditions during surgical treatment.

In Vivo Visualization of the Pericardium Meridian with Fluorescent Dyes

The anatomical basis of acupuncture meridians continues to be enigmatic. Although much attention has been placed on potential correlations with inter/intramuscular fascia or lower electrical impedance, animal studies performed in the past 40 years have shown that tracer dyes—specifically Tc-99m pertechnetate—injected at strategic skin points generate linear migrations closely aligning with acupuncture meridians. To evaluate whether this phenomenon is also observable in humans, we injected two fluorescent dyes—fluorescein sodium and indocyanine green (ICG)—into the dermal layer both at acupuncture points (PC5, PC6, and PC7) and a nonacupoint control. Fifteen healthy volunteers were enrolled in this study. Of the 19 trials of fluorescein injected at PC6, 15 (79%) were associated with slow diffusion of the dye proximally along a path matching closely with the pericardium meridian. Furthermore, the dye emerged and coalesced proximally at exactly acupoint PC3. Injections of ICG at the acupoints PC5, PC6, or PC7 showed a similar trajectory close to the injection site but diverged when migrating proximally, failing converge on acupoint PC3. Injections of either dye at an adjacent PC6-control did not generate any notable linear pathway. Both ultrasound imaging and vein-locating device did not reveal any corresponding vessels (arterial or venous) at the visualized tracer pathway but did demonstrate correlations with intermuscular fascia.

Effect of Line-Magnet Stimulation on HRV: A Double-Blind, Randomized, Crossover Trial

The acupuncture point mapped into the body meridian line has been the subject of extensive research; however, the scientific basis of the body meridian line remains unknown. In the present study, a pair of line-magnets was attached along the heart meridian line between HT4 and HT6 (intervention), and heart rate variability (HRV) was examined in a double-blind, randomized, crossover trial. Forty-five healthy young adults were randomly assigned into two groups and received two interventions in a different order. The only difference between the interventions was that the magnet pole was swapped. The results showed that the frequency-domain (LF, LF/HF) properties of HRV, which reflects underlying autonomic nervous system activity, changed when the magnetic pole’s direction along the heart meridian line was changed. This finding suggests that a line-magnet attached along to the heart meridian line may affect the cardiovascular system.

The difference in heat transport characteristics of the heart and lung meridians: A comparative study of COPD patients and healthy subjects

BACKGROUND

The vast majority of previous studies focused on the relationship between 1 meridian and 1 organ, and the comparison and specificity between 2 meridians is rarely explored. Thus, the aim of this study is to compare the heat transport characteristics between 2 different meridians and the specificity between them will also be investigated.

METHODS

The Lung and Heart meridians are chosen for comparison of 2 different meridians. We will enroll 120 subjects and divide them into the healthy control group, chronic obstructive pulmonary disease (COPD) group and healthy intervention group, in a 1:1:1 ratio. Infrared thermography (IRT) will be used to assess the heat transport characteristics of the Heart and Lung meridians. The specificity for the meridian-visceral association will be investigated by comparing the difference in heat transport characteristic between the Heart and Lung meridians in the healthy control group and COPD group. Meanwhile, moxibustion will be given to subjects in the Heart meridian and Lung meridian respectively in the healthy intervention group to verify the specificity for the surface-surface association.

RESULTS

The primary outcomes will be the temperature of corresponding sites along the Heart and Lung meridians.

CONCLUSION

This study will verify the specificity between different meridians by comparing the difference in heat transport characteristic. The findings will guide the selection of acupoints to optimize the therapeutic effect of acupuncture and help determine whether IRT could be used to assist in the diagnosis of COPD.

ETHICS AND DISSEMINATION

The study has been approved by the Third Affiliated Hospital of Zhejiang Chinese Medical University (Approval No. ZSLL-KY-2019-001G-01).

TRIAL REGISTRATION NUMBERS

NCT04046588.

A Low-Power Stable Wideband Current Source for Acupuncture Point Skin Impedance Measurements

A low-power stable wideband current source for acupuncture point skin impedance measurements has been designed employing a differential architecture and negative feedback. The circuits extend bandwidth to 1 MHz, reducing harmonic distortion to 0.24% at 1 MHz. The output impedance is 37 MΩ at 100 kHz and 11 MΩ at 1 MHz. The stability of the output current of the current source when connected to different loads is below 0.1% at frequencies up to 500 kHz and increases to 0.74% at 1 MHz. The circuit was manufactured in a 0.13-μm CMOS technology and measured results are presented. The area of the current source is 0.09 mm² and its consumption is 1.2 mW. It is intended for low-power acupuncture point skin impedance measurements.

Overcoming Barriers for Clinical Research of Acupuncture

Acupuncture is increasingly being used in the management of a wide range of symptoms. Despite decades of acupuncture research, a significant gap remains in translating evidence into specific and clear clinical guidelines for acupuncture practice. In this article, the authors discuss the gap between acupuncture research and clinical practice and exploring options to overcome the limitations of current clinical research of acupuncture.

Characterisation of Human Skin Impedance at Acupuncture Point Pc4 Ximen and pericardium meridian using the four-electrode method

Introduction

Traditional Chinese medicine offers several theories to explain the mechanism of acupuncture. One of these theories proposes that acupuncture points and meridians have unique electrical properties and their electrical skin impedance is lower than surrounding areas. The aim of this study was to evaluate the differences in electrical skin impedance between PC4 and the pericardium meridian compared with the surrounding areas.

Methods

Eighteen healthy subjects (10 women) were recruited to participate in the study. An impedance meter based on the four-electrode technique was designed specifically for the study. Twenty-five points were marked on the skin: one on the point PC4, four others on the pericardium meridian and 20 points around it. The electrical impedance of each point was measured with the four-electrode device.

Results

The mean electrical skin impedance at PC4 was significantly different from the 20 of the surrounding points but not significantly different from the four adjacent points. The mean skin impedance of the five points over the pericardium meridian was significantly different from that of parallel rows of points using repeated measures analysis of variance (p<0.001)

Conclusion

Within the possible limits of this measurement technique, skin impedance along the pericardium meridian is lower than surrounding areas, supporting the idea of different properties of the pericardium meridian compared with the control areas. Evidence on skin impedance at PC4 is inconclusive and further studies are needed.

Acupuncture and Neural Mechanism in the Management of Low Back Pain-An Update

Within the last 10 years, the percentage of low back pain (LBP) prevalence increased by 18%. The management and high cost of LBP put a tremendous burden on the healthcare system. Many risk factors have been identified, such as lifestyle, trauma, degeneration, postural impairment, and occupational related factors; however, as high as 95% of the cases of LBP are non-specific. Currently, LBP is treated pharmacologically. Approximately 25 to 30% of the patients develop serious side effects, such as drowsiness and drug addiction. Spinal surgery often does not result in a massive improvement of pain relief. Therefore, complementary approaches are being integrated into the rehabilitation programs. These include chiropractic therapy, physiotherapy, massage, exercise, herbal medicine and acupuncture. Acupuncture for LBP is one of the most commonly used non-pharmacological pain-relieving techniques. This is due to its low adverse effects and cost-effectiveness. Currently, many randomized controlled trials and clinical research studies have produced promising results. In this article, the causes and incidence of LBP on global health care are reviewed. The importance of treatment by acupuncture is considered. The efforts to reveal the link between acupuncture points and anatomical features and the neurological mechanisms that lead to acupuncture-induced analgesic effect are reviewed.

Various stem cells in acupuncture meridians and points and their putative roles

Traditional Chinese and Korean medicine uses various manipulations on acupuncture points/acupoints that are located along imaginary lines on the surface of a human body, which are called 'meridians'. Acupuncture has been used from the ancient time till now to cure various diseases, including for the purpose of regenerative medicine. In various studies, meridians are alternatively called as Bong-Han ducts, primo vessels, or hyaluronic-acid rich ducts, while acupoints are called Bong-Han corpuscles, primo nodes, or hyaluronic-acid rich nodes. Meridians and acupuncture points form a system that is now called primo vascular system (PVS), which is claimed to contain various kinds of stem cells. The stem cell size is between 1-5 microns. The smallest is the primo microcells that have a putative role in regeneration. Other stem cells are adult pluripotent and hematopoietic stem cells that play a role in extra bone marrow hematopoiesis. The presence of PVS has been reproduced by many studies. However, the various stem cells need further studies to prove their existence and function, and harvesting PVS to isolate the stem cells might harm the health of the donor.

Acute Physiological and Psychological Effects of Qigong Exercise in Older Practitioners

Qigong is a gentle exercise that promotes health and well-being. This study evaluated the acute physiological and psychological effects of one session of qigong exercise in older practitioners. A total of 45 participants (mean age, 65.14 years) were recruited. Meridian electrical conductance, State-Trait Anxiety Inventory (STAI), heart rate variability (HRV), and Short Form 36 (SF-36) were evaluated and compared before and after one session of qigong exercise. The results revealed that the electrical conductance of all meridians, except spleen and bladder meridians, increased significantly (p < 0.05). Compared with baseline values, upper to lower body ratio and sympathetic/vagal index were significantly improved and closer to 1 (p = 0.011 and p = 0.007, resp.). STAI-S and STAI-T scores decreased significantly (p < 0.001 and p = 0.001, resp.). The RR interval of HRV decreased significantly (p = 0.035), a significant positive correlation was observed between kidney meridian electrical conductance and SF-36 physical scores (r = 0.74, p = 0.018), and a positive correlation was observed between pericardium meridian electrical conductance and SF-36 mental scores (r = 0.50, p = 0.06). In conclusion, one session of qigong exercise increased meridian electrical conductance, reduced anxiety, and improved body and autonomic nervous system balance. These findings provide scientific evidence for acute physiological and psychological effects of qigong exercise in older practitioners.

Consensus in Traditional Chinese Medical Diagnosis in Open Populations

Objectives: An acceptable level of diagnostic agreement is a prerequisite for consistent administration of treatment. It is critical for investigating effectiveness of different treatment approaches using multiple practitioners. To the best of our knowledge, no previous investigation of diagnostic consensus using open populations in Chinese medicine (CM) has been reported. Investigations restricted to individual medical conditions, such as have been usually studied, do not reveal any information as to what occurs in real world clinical settings. This knowledge gap led to the current study being conducted. Design/Location/Subjects/Interventions: Investigating diagnostic agreement specifically in Traditional Chinese Medicine (TCM) in an open population, two or three practitioners diagnosed 35 subjects at the University of Technology, Sydney (UTS), TCM clinic. The practitioners were restricted to a list of the 56 most frequently used TCM diagnoses at the UTS clinic. Up to three diagnostic patterns per subject could be selected, with nominated patterns scored between 1 and 5. Outcome measures: Agreement was determined with two criteria, both expressed as simple percentages: pattern and linearly weighted agreements. Results: The results showed that 23% of practitioners obtained pattern agreement, while 19% demonstrated weighted agreement. Conclusion: There appears to be very low diagnostic agreement between practitioners. This is an important finding. If unchallenged by further investigation, the recognition of such poor diagnostic consensus may lead to rejection of TCM theory before it has been adequately assessed. Diagnostic agreement must be improved so that future investigations into treatment effectiveness or mechanisms of action are made on a valid basis. Additionally, the current TCM diagnostic format must be altered to allow the application of chance-removed statistics or the calculation of a standard error with open populations. This article is the first of a series of three that report problems in TCM diagnostic reliability and proposes solutions to the issues outlined.

Theoretical basis, application, reliability, and sample size estimates of a Meridian Energy Analysis Device for Traditional Chinese Medicine Research

OBJECTIVES:

The Meridian Energy Analysis Device is currently a popular tool in the scientific research of meridian electrophysiology. In this field, it is generally believed that measuring the electrical conductivity of meridians provides information about the balance of bioenergy or Qi-blood in the body.

METHODS AND RESULTS:

PubMed database based on some original articles from 1956 to 2014 and the authoŕs clinical experience. In this short communication, we provide clinical examples of Meridian Energy Analysis Device application, especially in the field of traditional Chinese medicine, discuss the reliability of the measurements, and put the values obtained into context by considering items of considerable variability and by estimating sample size.

CONCLUSION:

The Meridian Energy Analysis Device is making a valuable contribution to the diagnosis of Qi-blood dysfunction. It can be assessed from short-term and long-term meridian bioenergy recordings. It is one of the few methods that allow outpatient traditional Chinese medicine diagnosis, monitoring the progress, therapeutic effect and evaluation of patient prognosis. The holistic approaches underlying the practice of traditional Chinese medicine and new trends in modern medicine toward the use of objective instruments require in-depth knowledge of the mechanisms of meridian energy, and the Meridian Energy Analysis Device can feasibly be used for understanding and interpreting traditional Chinese medicine theory, especially in view of its expansion in Western countries.

Model acupuncture point: Bone marrow-derived stromal stem cells are moved by a weak electromagnetic field

AIM

To show the existence of a structural formative role of magnetic fields (MFs) with respect to biological objects by using our proposed model of an acupoint.

METHODS

We introduced a magnetised 10-100 μT metal rod (needle) into culture dishes with a negatively charged working surface and observed during 24 h how cells were arranged by MFs and by electrical fields (EFs) when attached. Rat and human bone marrow-derived stromal stem cells (rBMSCs and hBMSCs), human nonadherent mononuclear blood cells, NCTCs and A172 cells, and Escherichia coli (E. coli) were evaluated. The dish containing BMSCs was defined as the model of an acupoint. rBMSCs proliferative activity affected by the needle was investigated. For investigating electromagnetic field structures, we used the gas discharge visualisation (GDV) method.

RESULTS

During 24 h of incubation in 50-mm culture dishes, BMSCs or the nonadherent cells accumulated into a central heap in each dish. BMSCs formed a torus (central ring) with an inner diameter of approximately 10 mm only upon the introduction of the needle in the centre of the dish. The cells did not show these effects in 35- or 90-mm culture dishes or hydrophobic dishes or rectangular cuvettes. NCTCs and A172 cells showed unstable the effects and only up to two weeks after thawing. Moreover, we observed that the appearance of these effects depended on the season. In winter, BMSCs showed no the effects. GDV experiments revealed that the resonant annular illumination gradually formed from 10 to 18-20 s in polar solutions with and without cell suspension of BMSCs, NCTCs and E. coli when using circular 50-mm dishes, stimulation at 115 V and switching of the electrode poles at 1 kHz. All these data demonstrate the resonant nature of the central ring. Significant influence of MFs on the rBMSC proliferation rate was not observed.

CONCLUSION

BMSCs can be moved by MFs when in the presence of a constant EF and MF, when the cells are in the responsive functional state, and when there is a resonant relationship between them.

Altered Impedance of Ear Acupuncture Point MT2 in Breast Cancer Patients: A Preliminary Observation

Skin impedance at acupuncture points (APs) has been used as a diagnostic aid for more than 50 years. In this study, we have a diagnostic tool (JXT-2008) to measure the skin impedance of ear APs of 30 breast cancer patients and the corresponding skin impedance of ear APs of 30 healthy humans, and then we compared these changes in ear AP impedance in breast cancer patients and healthy individuals.

Investigation of the electrical impedance of acupuncture points and non-acupuncture points before and after acupuncture, using a four-electrode device

AIM

To evaluate the effect of acupuncture on skin electrical impedance of selected points, before and after acupuncture on one acupuncture point (PC6), using a four-electrode device.

METHODS

Six acupuncture and non-acupuncture points on both sides of the body were selected to evaluate the effects of acupuncture on electrical properties of these points.

RESULTS

There were no results significant differences of electrical impedance before and after acupuncture in the selected points.

CONCLUSIONS

According to our experimental set-up, acupuncture at one point without stimulation does not alter skin electrical impedance in healthy volunteers and there is no difference between acupuncture points and non-acupuncture points.

Plasma pharmacokinetics and lung distribution of tetrahydropalmatine after topical application of cold asthma recipe extract: Feishu (BL 13) versus Non-Feishu acupoint

ETHNOPHARMACOLOGICAL RELEVANCE

Acupoint application of cold asthma recipe (CAR) was a traditional Chinese medicine (TCM) method, widely used as an alternative medicine for clinical prevention of the common winter diseases of asthma and bronchitis. Tetrahydropalmatine (THP) was a main active ingredient of CAR extract. The aim of this study is to compare plasma pharmacokinetics and lung distribution of THP between Feishu (FS) acupoint (BL 13) and Non-Feishu (NFS) acupoint application of CAR extract by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

MATERIALS AND METHODS

The extract of CAR was topically administrated in FS and NFS acupoint of rats for plasma pharmacokinetics, and topically administrated in FS and NFS acupoint of mice for lung distribution. The plasma and lung homogenates were pretreated by protein precipitation with acetonitrile. Chromatographic separation was performed on an ACQUITY UPLC BEH C18 column with a mobile phase consisted of 0.1% formic acid in acetonitrile and 0.1% formic acid in water. The detection was accomplished by multiple-reaction monitoring (MRM) scanning in the positive electrospray ionization (ESI(+)) mode. All pharmacokinetic parameters were estimated by non-compartmental analysis.

RESULTS

A sensitive, accurate and precise UPLC-MS/MS method was successfully established for determination of THP in 100 μL plasma and lung homogenate. The lower limit of quantification (LLOQ) of THP was 0.05 ng/mL and 0.072 ng/mL, respectively. The pharmacokinetic results manifested that THP was absorbed and eliminated slowly in plasma. Additionally, it was found that there was significantly higher amount of THP absorbed into blood and lung after FS acupoint application compared to NFS acupoint application.

CONCLUSIONS

Both of the rat plasma pharmacokinetics and mice lung distribution of THP could support that FS acupoint application of CAR extract has greater advantages of absorption into the blood circulation and distribution in target tissue over NFS acupoint application. The results might be helpful in providing a rational explanation for why the TCM chose the acupoint application and elucidating the underlying mechanism of this treatment.

Do changes in electrical skin resistance of acupuncture points reflect menstrual pain? A comparative study in healthy volunteers and primary dysmenorrhea patients

Electrical skin resistance (ESR) measurements were performed with a four-electrode impedance detector at 10 points bilaterally on the first day of and the third day after menstruation in 48 healthy volunteers and 46 primary dysmenorrhea (PD) patients, to assess whether ESR changes of acupuncture points can reflect menstrual pain or not. The results showed statistical reductions in ESR imbalance ratio between left and right side that were detected at SP8 (Diji) and GB39 (Xuanzhong) (P < 0.05), and a statistical increase was detected at SP6 (Sanyinjiao) (P = 0.05) on the first day of menstruation compared with those values on the third day after menstruation in dysmenorrhea group. No significant differences were detected at other points within and between two groups (P > 0.05). This study showed that the imbalance of ESR at uterine-relevant points in PD patients is not significantly different from those of healthy women on both the 1st day of and the 3rd day after menstruation. The ESR imbalance ratio of certain points can either be lower or higher during menstruation in PD patients. The ESR property of acupuncture points needs to be investigated in further clinical trials with appropriate points, diseases, larger sample sizes, and optimal device.

System for simultaneous measurements of bilaterally symmetrical acupoints multifrequency impedances

Devices which can obtain comparable bilaterally symmetrical acupoints (BSA) multifrequency impedances (MFI) are often needed in the detection of the energy balance states of acupoints in traditional Chinese medicine. To satisfy these needs, a two-channel impedance measurement system has been introduced which is capable of accurately and simultaneously measuring BSA MFI. The system includes a set of five electrodes, two of which are injected with exciting current signal to synchronously and equally excite BSA; the other three electrodes are used as sensors to simultaneously sense the response signal from both sides. The system also includes a PC-based time-domain signal testing platform with arbitrary current waveform generation and three channels (one exciting current and two response voltages) simultaneously sampling, and a set of MFI simultaneously unbiased computing algorithms based on special odd multisine current signal input. Preliminary validating experiments suggest that the system allows accurate and synchronous measurement of BSA MFI at least in the frequency range of 10 Hz to 60 kHz, and the obtained BSA MFI are well comparable.

Hardware and software realization of EDSD for acupuncture research and practice

Traditional acupuncture as a diagnostic and therapeutic method has been known in China for more than 3000 years. Electrodermal screening tests (EDSTs) and electrodermal screening devices (EDSDs) that are based on the knowledge derived from traditional Chinese medicine appeared in the 1950s. This article deals with design, development and realization of such a device. The design considers the principles of two widely used EDSTs and modern trends in the field of electronics and data management. A computer program with simple user interface that provides graphic evaluation and intercomparison of measured data are presented. The designed system is suitable not only for acupuncture research but also for ordinary acupuncture diagnostics.

Acupuncture for hypoxic ischemic encephalopathy in neonates

BACKGROUND

Hypoxic ischemic encephalopathy (HIE) in the neonate is associated with high mortality and morbidity. Effective treatment options are limited and therefore alternative therapies such as acupuncture are increasingly used.

OBJECTIVES

We sought to determine the efficacy and safety of acupuncture on mortality and morbidity in neonates with HIE.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), Cochrane Neonatal Specialized Register, MEDLINE, AMED, EMBASE, PubMed, CINAHL, PsycINFO, WHO International Clinical Trials Registry Platform, and various Chinese medical databases in November 2012.

SELECTION CRITERIA

We planned to include randomized or quasi-randomized controlled trials comparing needle acupuncture to a control group that used no treatment, placebo or sham treatment in neonates (less than 28 days old) with HIE. Co-interventions were allowed as long as both the intervention and the control group received the same co-interventions. We excluded trials that evaluated therapy that did not involve penetration of the skin with a needle or trials that compared different forms of acupuncture only.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed trials for inclusion. If trials were identified, the review authors planned to assess trial quality and extract data independently. We planned to use the risk ratio (RR), risk difference (RD), and number needed to benefit (NNTB) or harm (NNTH) with 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) with 95% CI for continuous outcomes.

MAIN RESULTS

No trial satisfied our predefined inclusion criteria. Existing trials only evaluated acupuncture in older infants who survived HIE. There are currently no randomized controlled trials evaluating the efficacy of acupuncture for treatment of HIE in neonates. The safety of acupuncture for HIE in neonates is unknown.

AUTHORS' CONCLUSIONS

The rationale for acupuncture in neonates with HIE is unclear and the evidence from randomized controlled trial is lacking. Therefore, we do not recommend acupuncture for the treatment of HIE in neonates. High quality randomized controlled trials on acupuncture for HIE in neonates are needed.

Biophysical characteristics of meridians and acupoints: a systematic review

As an integral part of traditional Chinese medicine (TCM), acupuncture is a convenient and effective therapy with fewer adverse effects. Recently, researches on meridian essence have become core issues of modern TCM. Numerous experiments have demonstrated the objective existence of meridians by different technologies since 1950s, such as biophysics, biochemistry, and molecular biology. In this paper, we review biophysical studies on electric, acoustic, thermal, optical, magnetic, isotopic, and myoelectric aspects of meridians and acupoints. These studies suggest that meridians/acupoints have biophysical characteristics which are different from nonacupuncture points. Owing to the limitations of previous studies, future research using high-throughput technologies such as omics and multicenter randomized controlled trials should be performed to explore the acupuncture's mechanisms of action and demonstration of efficacy.

Fluid flow along venous adventitia in rabbits: is it a potential drainage system complementary to vascular circulations?

Background

Our previous research and other studies with radiotracers showed evidence of a centripetal drainage pathway, separate from blood or lymphatic vessels, that can be visualized when a small amount of low molecular weight tracer is injected subcutaneously into a given region on skin of humans. In order to further characterize this interesting biological phenomenon, animal experiments are designed to elucidate histological and physiologic characteristics of these visualized pathways.

Methods

Multiple tracers are injected subcutaneously into an acupuncture point of KI3 to visualize centripetal pathways by magnetic resonance imaging or fluorescein photography in 85 healthy rabbits. The pathways are compared with venography and indirect lymphangiography. Fluid flow through the pathways is observed by methods of altering their hydrated state, hydrolyzing by different collagenases, and histology is elucidated by optical, fluorescein and electron microscopy.

Results

Histological and magnetic imaging examinations of these visualized pathways show they consist of perivenous loose connective tissues. As evidenced by examinations of tracers’ uptake, they appear to function as a draining pathway for free interstitial fluid. Fluorescein sodium from KI3 is found in the pathways of hind limbs and segments of the small intestines, partial pulmonary veins and results in pericardial effusion, suggesting systematical involvement of this perivenous pathway. The hydraulic conductivity of these pathways can be compromised by the collapse of their fiber-rich beds hydrolyzed by either of collagenase type I, III, IV or V.

Conclusions

The identification of pathways comprising perivenous loose connective tissues with a high hydraulic conductivity draining interstitial fluid in hind limbs of a mammal suggests a potential drainage system complementary to vascular circulations. These findings may provide new insights into a systematically distributed collagenous connective tissue with a circulatory function and their potential relevance to the nature of acupuncture meridians.

Development and evaluation of a novel four-electrode device system for monitoring skin impedance

Qi, meridians, and acupoints are important issues in Chinese medicine. One of the theories claims that acupuncture points and meridians have unique electrical properties. The associations between acupuncture points or meridians and special electrical properties are still under debate. In the current study, we introduced and explained a device for this kind of research and evaluated the reliability of this device as well as effects of pressure, cleaning the skin by alcohol and exfoliation on electrical skin measurements. Fifteen subjects (10 female, 5 male) were recruited to participate in the study. An impedance meter based on the four-electrode technique was designed and fabricated specifically for this study. The effects of pressure, cleaning of the skin by alcohol, and exfoliation on electrical skin impedance were evaluated separately. The device repeatability was also evaluated 30 times in a 30 minutes period. Scale weight up to 200 grams, cleaning the skin with alcohol, and exfoliation didn't affect the performance of this device. The device performance didn't change significantly during the 30 minutes measurement either. The new system we evaluated can be a reliable tool for researches on electrical skin impedance in acupuncture, as its performance is fairly stable even in the presence of various confounding factors such as various pressures on the probe, cleaning the skin with alcohol and exfoliation.

Acupuncture for autism spectrum disorders (ASD)

BACKGROUND

Autism spectrum disorders (ASD) are characterized by impairment in social interaction, impairment in communication and lack of flexibility of thought and behavior. Acupuncture, which involves the use of needles or pressure to specific points on the body, is used widely in Traditional Chinese Medicine and increasingly within a western medical paradigm. It has sometimes been used as a treatment aimed at improving ASD symptoms and outcomes, but its clinical effectiveness and safety has not been rigorously reviewed.

OBJECTIVES

To determine the effectiveness of acupuncture for people with ASD in improving core autistic features, as well as communication, cognition, overall functioning and quality of life, and to establish if it has any adverse effects.

SEARCH STRATEGY

We searched the following databases on 30 September 2010: CENTRAL (The Cochrane Library, 2010, Issue 3), MEDLINE (1950 to September 2010 Week 2), EMBASE (1980 to 2010 Week 38), PsycINFO, CINAHL, China Journal Full-text Database, China Master Theses Full-text Database, China Doctor Dissertation Full-text Database, China Proceedings of Conference Database, Index to Taiwan Periodical Literature System, metaRegister of Controlled Trials and the Chinese Clinical Trials Registry. We also searched AMED (26 February 2009) and Dissertation Abstracts International (3 March 2009), but these were no longer available to the authors or editorial base at the date of the most recent search. TCMLARS (Traditional Chinese Medical Literature Analysis and Retrieval System) was last searched on 3 March 2009.

SELECTION CRITERIA

We included randomized and quasi-randomized controlled trials. We included studies comparing an acupuncture group with at least one control group that used no treatment, placebo or sham acupuncture treatment in people with ASD. We excluded trials that compared different forms of acupuncture or compared acupuncture with another treatment.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted trial data and assessed the risk of bias in the trials. We used relative risk (RR) for dichotomous data and mean difference (MD) for continuous data.

MAIN RESULTS

We included 10 trials that involved 390 children with ASD. The age range was three to 18 years and the treatment duration ranged from four weeks to nine months. The studies were carried out in Hong Kong, mainland China and Egypt.Two trials compared needle acupuncture with sham acupuncture and found no difference in the primary outcome of core autistic features (RFRLRS total score: MD 0.09; 95% CI -0.03 to 0.21, P = 0.16), although results suggested needle acupuncture might be associated with improvement in some aspects of the secondary outcomes of communication and linguistic ability, cognitive function and global functioning.Six trials compared needle acupuncture plus conventional treatment with conventional treatment alone. The trials used different primary outcome measures and most could not demonstrate effectiveness of acupuncture in improving core autistic features in general, though one trial reported patients in the acupuncture group were more likely to have improvement on the Autism Behavior Checklist (RR 1.53; 95% CI 1.09 to 2.16, P = 0.02) and had slightly better post-treatment total scores (MD -5.53; 95% CI -10.76 to -0.31, P = 0.04). There was no evidence that acupuncture was effective for the secondary outcome of communication and linguistic ability, though there seemed to be some benefit for the secondary outcomes of cognitive function and global functioning.Two trials compared acupressure plus conventional treatment with conventional treatment alone and did not report on the primary outcome. Individual study results suggested there may be some benefit from acupressure for certain aspects of the secondary outcomes of communication and linguistic ability, cognitive function and global functioning.Four trials reported some adverse effects, though there was little quantitative information, and at times both intervention and control groups experienced them. Adverse effects noted included bleeding, crying due to fear or pain, irritability, sleep disturbance and increased hyperactivity. None of the trials reported on quality of life.There are a number of problems with the evidence base: the trials were few in number and included only children; six of the trials were at high risk of bias; they were heterogeneous in terms of participants and intervention; they were of short duration and follow-up; they reported inconsistent and imprecise results, and, due to carrying out large numbers of analyses, they were at risk of false positivity.

AUTHORS' CONCLUSIONS

Current evidence does not support the use of acupuncture for treatment of ASD. There is no conclusive evidence that acupuncture is effective for treatment of ASD in children and no RCTs have been carried out with adults. Further high quality trials of larger size and longer follow-up are needed.

Electrical characterization of proposed transpositional acupoints on the urinary bladder meridian in a rat model

Specific electrical characteristicsof acupointswere investigated on the urinary bladder (BL) meridian in 14 rats. BL acupointsand non-acupoints on the back were selected and their electrical voltages were measured by using aSPACsystem.The mean voltages of each point or each line were statistically analyzed by using the ANOVA test.The BL meridian showed voltages higher than those of the reference line (P < .05). Bilateral 1st BL lines presented higher voltages than bilateral 2nd BL lines (P < .05). Most BL acupoints had voltageshigher than those for the corresponding reference points (P < .05). In particular, theright BL16 exhibited the biggest difference from the reference point, followed by the left extra BL point-2, the right BL27, the left BL17, and theleft BL45. Additionally, the distributions of neurofilamentsfor several points were investigated by using immunohistochemistry. There was a trend for the BL acupoints to have larger numbers of neurofilaments than the reference points, and that trend seemed to be directly proportional to the difference in voltage between the points.In conclusion, BL acupoints on the back in ratsexhibited specific electric and histologic characteristics. Therefore, those acupointsmay be utilized to investigate the efficacy of acupuncturewith laboratory animals.

Dielectric properties of human skin at an acupuncture point in the 50-75 GHz frequency range: a pilot study

The reason for using acupuncture points as exposure sites in some applications of millimeter wave therapy has been unclear. Acupuncture points have been suspected to exhibit particular direct current (DC), low-frequency electrical and optical properties compared to surrounding skin. To assess if such a biophysical correlation could exist at millimeter wave frequencies used in the therapy, we investigated the dielectric properties of an acupuncture point on the forearm skin within the 50-75 GHz range. These properties were compared with those of a neighboring ipsilateral control area and a corresponding contralateral control area. The complex reflection coefficient at the end of an open-ended rectangular waveguide loaded with a Teflon plug was measured with a vector network analyzer. A suitable model of the aperture admittance was used to calculate the dielectric properties of the skin at the measured spots. Statistical analyses were conducted with an ANOVA to compare the three sites. From these analyses, the dielectric properties of the acupuncture site were found to be somewhat different from those of surrounding non-acupuncture sites from 50 to about 61 GHz, in the case of the real part of the complex permittivity.

A multichannel system for continuous measurements of skin resistance and capacitance at acupuncture points

Electrodermal screening (EDS) is based on three commonly held assumptions: acupuncture points (APs) have lower electrical resistance than non-APs; resistance at APs varies with health and disease; and effective acupuncture treatments are associated with normalization of resistance at APs. Although evidence confirming these assumptions is limited, EDS is frequently practiced worldwide. Researchers are also beginning to assess EDS' utility as an outcome measure in acupuncture trials. Fundamental in developing EDS as a research tool is the need for an accurate and reliable measurement. We developed an automated multichannel prototype system, the Octopus, and recorded electrical resistance and capacitance at eight skin sites in 33 healthy participants over 2 hours. The Octopus accurately measured against known resistors (within 2.5% of the mean value) and capacitors (within 10% of the mean value), and yielded repeatable readings at all eight skin sites: LR 1 (r=0.79), SP 1 (r=0.79), toe non-AP (r=0.77), LU 9 (r=0.97), PC 6 (r=0.96), wrist non-APs (r=0.97), SP 6 (r=0.96), and leg non-APs (r=0.97). Resistance at APs was significantly lower than the nearby non-APs in one out of three comparisons.

Possible applications for fascial anatomy and fasciaology in traditional Chinese medicine

Research using medical imaging instruments such as computed tomography and magnetic resonance imaging has led to the proposal that the fascial network distributed over the human body is the anatomical basis for the acupoints and meridians of traditional Chinese medicine. Therefore, we put forward a new theory of anatomy called fascial anatomy. In fascial anatomy, a human body is divided into two major systems. One is the supporting-storing system of unspecialized connective tissues. The other is a functional system. An undifferentiated non-specific connective tissue network, with the participation of the nervous and the immune systems, constitutes the supporting-storing system of the human body. The various differentiated functional cells in the body that are supported and surrounded by the supporting-storing system constitute the functional system. The discipline that studies the supporting-storing system and the mutual relationship between this system and the functional system in a living human body is called fasciaology. The establishment of fascial anatomy and fasciaology opens a new research field in anatomy; consequently, fasciaology will play a significant role in biological medicine and traditional Chinese medical research, as well as future clinical practice.

Acupuncture on the Endometrial Morphology, the Serum Estradiol and Progesterone Levels, and the Expression of Endometrial Leukaemia-inhibitor Factor and Osteopontin in Rats

Although it is well known that acupuncture has beneficial effects on a variety of medical conditions especially in pain relief, nausea, and vomiting, it remains controversial whether it has positive impact on the female reproduction. The present study aimed to evaluate whether the following endometrial receptivity factors: the endometrial morphology, the hormone concentrations, and the protein expression of endometrial leukaemia-inhibitory factor (LIF) and osteopontin (OPN) could be improved by the acupuncture in clomiphene citrate(CC)-induced rat model during implantation period. Results showed that, compared with the CC group, glandular development advanced, the serum estradiol levels decreased significantly, and the glandular area and endometrial LIF and OPN expression were significantly higher in acupuncture group. There were no significant differences in serum progesterone levels, endometrial thickness, and stromal area between groups. These results suggest that acupuncture can improve certain aspects of endometrial receptivity in CC-induced rat model during implantation period, which might result in endometrial state better to female reproduction.

Electrical impedance of acupuncture meridians: the relevance of subcutaneous collagenous bands

Background

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.

Methods/Results

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.

Conclusion/Significance

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.

Chinese medicine and biomodulation in cancer patients--Part one

Traditional Chinese Medicine (tcm) may be integrated with conventional Western medicine to enhance the care of patients with cancer. Although tcm is normally implemented as a whole system, recent reductionist research suggests mechanisms for the effects of acupuncture, herbs, and nutrition within the scientific model of biomedicine. The health model of Chinese medicine accommodates physical and pharmacologic interventions within the framework of a body–mind network. A Cartesian split does not occur within this model, but to allow for scientific exploration within the restrictions of positivism, reductionism, and controls for confounding factors, the components must necessarily be separated. Still, whole-systems research is important to evaluate effectiveness when applying the full model in clinical practice. Scientific analysis provides a mechanistic understanding of the processes that will improve the design of clinical studies and enhance safety. Enough preliminary evidence is available to encourage quality clinical trials to evaluate the efficacy of integrating tcm into Western cancer care.

Characteristics of electrical skin resistance at acupuncture points in healthy humans

OBJECTIVES

The aim of this study was to evaluate the phenomenon of electrical skin resistance (ESR) changes at different acupuncture points (APs).

SETTING

This single-blinded study was performed at the hospital of the University of Munich.

DESIGN

Six common APs were measured (TE5, PC6, LU6, ST36, SP6, GB39) in 53 subjects. Subgroups were formed with varying time intervals for follow-ups (1 minute, 1 hour, 1 week) and a varying grade of reduction of the stratum corneum.

METHODS

Electrical skin resistance measurements (ESRMs) were taken from a skin area of 6 x 6 cm using an array consisting of 64 (8 x 8) electrodes. The electrodes corresponding to the AP were located and the ESRM results were compared to those of the surrounding electrodes. The methodological setting made it possible to minimize major influence factors on electrical skin impedance measurements.

RESULTS

A total of 631 ESRMs was evaluated: In 62.8% of the measured APs, no significant ESR difference was found. In 234 (37.2%) of the ESRMs, the ESR at the AP was significantly different from the surrounding skin area, with 163 (25.9%) points showing a lower and 71 (11.3%) points showing a higher ESR. Reproducibility was extremely high after 1 minute but was low after 1 hour and 1 week.

CONCLUSIONS

This study shows that electrical skin resistance at APs can either be lower or higher compared to the surrounding area. The phenomenon is characterized by high short-term and low long-term reproducibility. Therefore, we conclude that APs might possess specific transient electrical properties. However, as the majority of the measured APs did not show a changed ESR, it cannot be concluded from our data that electrical skin resistance measurements can be used for acupuncture point localization or diagnostic/therapeutic purposes.

INCREASED TEMPERATURE AT ACUPUNCTURE POINTS INDUCED BY WEIGHT REDUCTION IN OBESE PATIENTS: A PRELIMINARY STUDY

This study investigated the temperature changes at acupuncture points resulting from a weight reduction program. A standard method using a digital infrared thermographic imaging device was employed to monitor the temperature at 20 acupuncture points in 32 participants treated for obesity at an Oriental obesity clinic. There were significant temperature increases at all of the acupuncture points except for LI4 (Hegu) and TE5 (Waiguan). The mean total temperature change at the acupuncture points was significantly correlated with the BMI change (r = .588, p < .001). The weight-reduction-induced increase in temperature at acupuncture points may reflect improvements in the circulation of energy flows. However, further study is necessary to understand fully the relationship between the temperature at acupuncture points and weight reduction, including the use of appropriate controls.

Sham acupuncture may be as efficacious as true acupuncture: a systematic review of clinical trials

OBJECTIVE

This study sought to determine whether sham acupuncture is as efficacious as true acupuncture, as defined by traditional acupuncture theories.

METHODS

A systematic review was conducted of clinical trials that used sham acupuncture controls with needle insertion at wrong points (points not indicated for the condition) or non-points (locations that are not known acupuncture points). This study used a convenience sample of 229 articles resulting from a PubMed search using the keyword "acupuncture" and limited to "clinical trials" published in English in 2005 or 2006. Studies were categorized by use of wrong points versus non-points and the use of normal insertion and stimulation versus superficial insertion or minimal stimulation.

RESULTS

Thirty-eight acupuncture trials were identified. Most studies (22/38 = 58%) found no statistically significant difference in outcomes, and most of these (13/22 = 59%) found that sham acupuncture may be as efficacious as true acupuncture, especially when superficial needling was applied to non-points.

CONCLUSIONS

The findings cast doubt on the validity of traditional acupuncture theories about point locations and indications. Scientific rationales for acupuncture trials are needed to define valid controls, and the theoretical basis for traditional acupuncture practice needs to be re-evaluated.

Prospective tests on biological models of acupuncture

The biological effects of acupuncture include the regulation of a variety of neurohumoral factors and growth control factors. In science, models or hypotheses with confirmed predictions are considered more convincing than models solely based on retrospective explanations. Literature review showed that two biological models of acupuncture have been prospectively tested with independently confirmed predictions: The neurophysiology model on the long-term effects of acupuncture emphasizes the trophic and anti-inflammatory effects of acupuncture. Its prediction on the peripheral effect of endorphin in acupuncture has been confirmed. The growth control model encompasses the neurophysiology model and suggests that a macroscopic growth control system originates from a network of organizers in embryogenesis. The activity of the growth control system is important in the formation, maintenance and regulation of all the physiological systems. Several phenomena of acupuncture such as the distribution of auricular acupuncture points, the long-term effects of acupuncture and the effect of multimodal non-specific stimulation at acupuncture points are consistent with the growth control model. The following predictions of the growth control model have been independently confirmed by research results in both acupuncture and conventional biomedical sciences: (i) Acupuncture has extensive growth control effects. (ii) Singular point and separatrix exist in morphogenesis. (iii) Organizers have high electric conductance, high current density and high density of gap junctions. (iv) A high density of gap junctions is distributed as separatrices or boundaries at body surface after early embryogenesis. (v) Many acupuncture points are located at transition points or boundaries between different body domains or muscles, coinciding with the connective tissue planes. (vi) Some morphogens and organizers continue to function after embryogenesis. Current acupuncture research suggests a convergence of the neurophysiology model, the connective tissue model and the growth control model. The growth control model of acupuncture set the first example of a biological model in integrative medicine with significant prediction power.

Developments in acupuncture research: big-picture perspectives from the leading edge

On November 8-9, 2007, the Society for Acupuncture Research (SAR) hosted an international conference to mark the tenth anniversary of the landmark NIH [National Institutes of Health] Consensus Development Conference on Acupuncture. More than 300 acupuncture researchers, practitioners, students, funding agency personnel, and health policy analysts from 20 countries attended the SAR meeting held at the University of Maryland School of Medicine, Baltimore, MD. This paper summarizes important invited lectures in the area of how the field has developed in the past decade, along with a focus on appropriate strategies for advancing the field. Specific topics include: the impact of the 1997 NIH Acupuncture Consensus Conference on acupuncture research; whole-system strategies for developing the evidence without distorting the medicine; use of qualitative research methods to explore acupuncture as a complex intervention; use of qualitative research approaches to explore some "missing" topics in acupuncture research; and the impact of acupuncture research on clinical practice. A concluding section focuses on future directions in acupuncture research.

Electrical properties of acupuncture points and meridians: a systematic review

According to conventional wisdom within the acupuncture community, acupuncture points and meridians are special conduits for electrical signals. This view gained popularity after anecdotal reports and clinical studies asserted that these anatomical structures are characterized by lower electrical impedance compared to adjacent controls. To ascertain whether evidence exists to support or refute this claim, we conducted a systematic review of studies directly evaluating the electrical characteristics of acupuncture structures and appropriate controls. We searched seven electronic databases until August 2007, hand-searched references, and consulted technical experts. We limited the review to primary data human studies published in English. A quality scoring system was created and employed for this review. A total of 16 articles representing 18 studies met inclusion criteria: 9 examining acupuncture points and 9 examining meridians. Five out of 9 point studies showed positive association between acupuncture points and lower electrical resistance and impedance, while 7 out of 9 meridian studies showed positive association between acupuncture meridians and lower electrical impedance and higher capacitance. The studies were generally poor in quality and limited by small sample size and multiple confounders. Based on this review, the evidence does not conclusively support the claim that acupuncture points or meridians are electrically distinguishable. However, the preliminary findings are suggestive and offer future directions for research based on in-depth interpretation of the data.