Skin Impedance Measurements for Acupuncture Research: Development of a Continuous Recording System

Skin impedance at acupuncture points (APs) has been used as a diagnostic/therapeutic aid for more than 50 years. Currently, researchers are evaluating the electrophysiologic properties of APs as a possible means of understanding acupuncture's mechanism. To comprehensively assess the diagnostic, therapeutic and mechanistic implications of acupuncture point skin impedance, a device capable of reliably recording impedances from 100 kΩ to 50 MΩ at multiple APs over extended time periods is needed. This article describes design considerations, development and testing of a single channel skin impedance system (hardware, control software and customized electrodes). The system was tested for accuracy against known resistors and capacitors. Two electrodes (the AMI and the ORI) were compared for reliability of recording over 30 min. Two APs (LU 9 and PC 6) and a nearby non-AP site were measured simultaneously in four individuals for 60 min. Our measurement system performed accurately (within 5%) against known resistors (580 kΩ–10 MΩ) and capacitors (10 nF–150 nF). Both the AMI electrode and the modified ORI electrode recorded skin impedance reliably on the volar surface of the forearm (r = 0.87 and r = 0.79, respectively). In four of four volunteers tested, skin impedance at LU 9 was less than at the nearby non-AP site. In three of four volunteers skin impedance was less at PC 6 than at the nearby non-AP site. We conclude that our system is a suitable device upon which we can develop a fully automated multi-channel device capable of recording skin impedance at multiple APs simultaneously over 24 h.

[1]  R O Potts,et al.  Electrical properties of skin at moderate voltages: contribution of appendageal macropores. , 1998, Biophysical journal.

[2]  F. Chiappelli,et al.  Evidence-Based Research in Complementary and Alternative Medicine II: The Process of Evidence-Based Research , 2006, Evidence-based complementary and alternative medicine : eCAM.

[3]  I Cosic,et al.  Mapping acupuncture points using multi channel device. , 1998, Australasian physical & engineering sciences in medicine.

[4]  D. Bresler,et al.  An experimental evaluation of auricular diagnosis: The somatotopic mapping of musculoskeletal pain at ear acupuncture points , 1980, Pain.

[5]  H. Keino,et al.  Development of the low impedance points in the auricular skin of experimental peritonitis rats. , 1991, The American journal of Chinese medicine.

[6]  M Levin.  Comments on "Special report: recommendations for safe current limits for electrocardiographs'. , 1997, Circulation.

[7]  K. Arakawa,et al.  Characteristics of reactive electropermeable points on the auricles of coronary heart disease patients–K. Saku et al.: Reactive electropermeable points in CHD , 1993, Clinical cardiology.

[8]  B. J. Winer,et al.  Statistical Principles in Experimental Design, 2nd Edition. , 1973 .

[9]  N. Hoshimiya,et al.  A basic study about multi channel measurement of skin impedance vector loci on the acupuncture points , 2001, 2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[10]  A. Mayer-Gindner,et al.  Newly Explored Electrical Properties of Normal Skin and Special Skin Sites / Neue Untersuchungen zu elektrischen Eigenschaften normaler Haut und spezieller Hautpunkte , 2004, Biomedizinische Technik. Biomedical engineering.

[11]  J.H. Cho,et al.  Frequency dependence of impedances at the acupuncture point Quze (PC3) , 2002, IEEE Engineering in Medicine and Biology Magazine.

[12]  C. X. Falk,et al.  Methodological investigations for a multisite trial of auricular acupuncture for cocaine addiction: a study of active and control auricular zones. , 1996, Journal of substance abuse treatment.

[13]  Andrew A. Marino,et al.  Electrical Correlates of Acupuncture Points , 1975, IEEE Transactions on Biomedical Engineering.

[14]  H. Langevin,et al.  Relationship of acupuncture points and meridians to connective tissue planes , 2002, The Anatomical record.

[15]  R. Voll.  TWENTY YEARS OF ELECTROACUPUNCTURE DIAGNOSIS IN GERMANY. A PROGRESS REPORT , 1975 .

[16]  G. Lewith,et al.  A double blind, randomized, controlled investigation of electrodermal testing in the diagnosis of allergies. , 1997, Journal of alternative and complementary medicine.

[17]  B. J. Winer.  Statistical Principles in Experimental Design , 1992 .

[18]  Sverre Grimnes,et al.  Line patterns in the mosaic electrical properties of human skin-a cross-correlation study , 2001, IEEE Transactions on Biomedical Engineering.

[19]  J. Mcnames,et al.  Reliability of the Prognos electrodermal device for measurements of electrical skin resistance at acupuncture points. , 2004, Journal of alternative and complementary medicine.

[20]  Nicole A. Bouffard,et al.  Subcutaneous tissue fibroblast cytoskeletal remodeling induced by acupuncture: Evidence for a mechanotransduction‐based mechanism , 2006, Journal of cellular physiology.

[21]  J. Hyvärinen,et al.  Low-resistance skin points that may coincide with acupuncture loci. , 1977, Medical biology.

[22]  Junru Wu,et al.  Electrical impedance along connective tissue planes associated with acupuncture meridians , 2005, BMC complementary and alternative medicine.

[23]  T. Matsumoto,et al.  Acupuncture, electric phenomenon of the skin, and postvagotomy gastrointestinal atony. , 1973, American journal of surgery.

[24]  C. Görner,et al.  Reliabilität der energetischen Meridianmessung mit Prognos A® , 1998, Complementary Medicine Research.

[25]  B. Gandevia,et al.  DECLARATION OF HELSINKI. , 1964, The Medical journal of Australia.

[26]  T. Usichenko,et al.  Detection of ear acupuncture points by measuring the electrical skin resistance in patients before, during and after orthopedic surgery performed under general anesthesia. , 2003, Acupuncture & electro-therapeutics research.

[27]  J. Jessel-Kenyon,et al.  A Statistical Comparison of Repeatability in Three Commonly Used Bioelectronic Devices: Kirlian Photography, the Segmental Electrogram, and the Ami of Motoyama , 1998 .

[28]  John R. Williams.  DECLARATION OF HELSINKI , 1964 .

[29]  F. Chiappelli,et al.  Evidence-based Research in Complementary and Alternative Medicine I: History , 2005, Evidence-based complementary and alternative medicine : eCAM.

[30]  D. Irnich,et al.  Eine neue Sensortechnik zur Messung von elektrischen Potentialprofilen der menschlichen Haut an Akupunkturpunkten , 2006, Complementary Medicine Research.

[31]  B. Rowley,et al.  An Investigation of the Existence of Electrically Located Acupuncture Points , 1979 .

[32]  G. Lewith.  Can we evaluate electrodermal testing? , 2003, Complementary Therapies in Medicine.

[33]  S. Holgate,et al.  Is electrodermal testing as effective as skin prick tests for diagnosing allergies? A double blind, randomised block design study , 2001, BMJ : British Medical Journal.

[34]  G. Passalacqua,et al.  A double‐blind, placebo‐controlled study on the diagnostic accuracy of an electrodermal test in allergic subjects , 2002, Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology.

[35]  D B Geselowitz,et al.  Recommendations for safe current limits for electrocardiographs. A statement for healthcare professionals from the Committee on Electrocardiography, American Heart Association. , 1996, Circulation.