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Variations In Electrical Waveform Patterns With
Percutaneous Electroacupuncture Stimulation: Case Study
Robert L. Harmon, MD
ABSTRACT
A single-case pilot study was commenced to assess variation of electrical waveform responses with 2 electroacupuncture stimulation montages. The examiner's left lower limb was stimulated using a monopolar electromyograph needle electrode over acupuncture points LR 3 (negative) to LR 8 (positive), and then SP 6 to SP 9. Averaged needle electromyographic recordings were made at selected acupuncture points at or below the knee, both on and off the principal meridian subcircuit. Waveform amplitude differences were noted between the 2 stimulation montages; the electrical activity did not stay confined to the stimulated principal meridian subcircuit. SP 6 to SP 9 stimulation produced larger peak-to-peak response amplitudes than LR 3 to LR 8 stimulation overall. Further studies should demonstrate how these findings might influence electroacupuncture treatment efficacy.
KEY WORDS
Acupuncture Points, Volume Conduction, Electroacupuncture, Muscles
INTRODUCTION
From a neurophysiological perspective, electrical fields would be expected to follow principles of volume conduction within the tissues of the body.1 However, some of the acupuncture concepts of meridian "energy flow" would support the concept of energy movement through a channel system.2 A prior pilot study3 investigating the importance of acupuncture-like transcutaneous electrical nerve stimulation electrode placement on transcutaneously recorded electrical waveforms demonstrated the presence of recordable waveforms at acupuncture points off the stimulated principal meridian.
This additional single-case pilot study was undertaken to further assess electrical waveform propagation within a principal meridian subcircuit2 using percutaneous stimulating and recording electrodes to refine the methodologies for a planned larger study.
METHODS
The researcher used his left lower limb in this pilot study. No effort was made to exclude potentially coexisting neurological or musculoskeletal disorders. Using an electromyograph (XLTEK Neuromax; Oakville, Ontario, Canada) with filter settings of 2-10,000 Hz, 2 ms/division sweep, and gain adjusted to record peak-to-peak waveform response, the left lower limb was stimulated with 33.0 mA for 0.1 ms by a monopolar needle electrode cathode inserted into LR 3 (negative) to LR 8 (positive), and then SP 6 (negative) to SP 9 (positive). The surface electrode anode was placed over the patella. Recordings using similar monopolar needle electrodes were made at KI 10, KI 3, BL 40, BL 60, GB 34, and ST 36, with the surface reference electrode placed over the patella. Both stimulating and recording needle electrodes were inserted until the sensation of De Qi was experienced by the researcher. A total of 10 tracings were obtained and averaged for each recording site used. Waveform peak-to-peak amplitudes were measured manually. Qualitative comparisons of the data were made.
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Table 1. Subject Volume Conducted Waveform Peak-to-Peak Amplitudes With Stimulation at Acupuncture Points
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Amplitude, mV
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Recording
Site
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SP 6 to SP 9
Stimulation
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LR 3 to LR 8
Stimulation
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KI 10
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1900.00
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0.00
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BL 40
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650.00
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66.00
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BL 60
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7500.00
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333.00
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GB 34
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966.00
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33.00
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KI 3
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7700.00
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250.00
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ST 36
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1600.00
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50.00
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RESULTS
A summary of the data is presented in Table 1. There were relative differences in peak-to-peak amplitude at the recording sites between the 2 stimulus montages (Table 1), with SP 6 to SP 9 stimulation producing larger peak-to-peak response amplitudes than LR 3 to LR 8 stimulation overall at the recording sites.
DISCUSSION
Electrical activity from the stimulated principal meridian subcircuit was noted to be present on both related and unrelated meridian subcircuits2 for both stimulation montages in the lower extremity studied, supporting findings of the earlier pilot study3 using surface stimulating and recording electrodes, but still too small a study to generalize findings to a larger population. The waveform amplitudes in the present case study tended to be smaller at recording sites at a distance from the LR 3 and SP 6 negative stimulating electrodes as would be expected in a process associated with volume conduction,1,4 with electrical waveform alteration associated with changes in recording electrode distance from the generator source, and with propagation through tissues of varying density. As SP 6 is anatomically located close to the course of the tibial nerve,5,6 electrical activity generated by stimulation of this nerve and the associated innervated musculature also would be expected to contribute to the overall larger amplitude waveforms that were recorded with SP 6 to SP 9, when compared with LR 3 to LR 8 stimulation. Of note, however, some concepts of meridian energy flow would also support the observation of the spread of electrical activity, occurring through intersection of the 3 Yin lower limb channels at SP 6 and circulation through other networks (e.g., Luo vessels).2
This observation may have implications in the use of electroacupunture in clinical situations. The finding of electrical activity at acupuncture points on unrelated meridian subcircuits3 suggests that additional acupuncture points stimulation may occur more than the treating practitioner intended. This may have beneficial effects in the treatment setting if a higher "dose" of acupuncture points input was required for a patient's specific condition, or adverse effects if the opposite was true. In addition, this may explain some of the "nonspecific" effects of electroacupuncture on conditions unrelated to the stimulated subcircuit. Further studies in the clinical setting are required to investigate these possibilities.
CONCLUSION
The electrical waveforms produced by percutaneous acupuncture stimulation can differ, depending on the stimulation montage used. Further studies regarding waveform patterns in a larger population and the clinical utility of this information in electroacupuncture treatment appear indicated.
REFERENCES
- Dumitru D, DeLisa JA. AAEM minimonograph #10: volume conduction. Muscle Nerve. 1991;14:605-624.
- Helms JM. Acupuncture Energetics: A Clinical Approach for Physicians. Berkeley, CA: Medical Acupuncture Publishers; 1995.
- Harmon RL, Segal KV, Sharma J. Volume-conducted waveform patterns with surface acupuncture point stimulation. Am J Phys Med Rehabil. 1999;78:187.
- Dimitru D. Volume Conduction: Electrodiagnostic Medicine. Philadelphia, PA: Hanley & Belfus Inc/Mosby; 1995.
- Last RJ. Anatomy: Regional and Applied. New York, NY: Churchill Livingstone; 1978.
- Deadman P, Al-Khafaji M, Baker K. A Manual of Acupuncture. East Sussex, England: Journal of Chinese Medicine Publications; 1998.
AUTHOR INFORMATION
Dr Robert L. Harmon is in private practice in Physical Medicine and Rehabilitation in Evans, Georgia. He is also a Clinical Associate Professor in the Departments of Medicine and Neurology at The Medical College of Georgia in Augusta, GA.
Robert L. Harmon, MD, MS*
4409 Evans to Locks Rd
Evans, GA 30809
Phone: 706-396-7671 • Fax: 706-396-7676 • E-mail: rharmon@pmrehab.net
*Correspondence and reprint requests
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