Abstract Details

Title Acupuncture-induced Changes in Nociception, Measured by Pain-related Evoked Potentials: A Pilot Mechanistic Study

Topic Pain

Presentation(s) P1 - Poster Session 1 (9:00 AM-5:00 PM)

Poster/Presentation
Number 446

Objective This pilot mechanistic study aims to assess the feasibility of using advanced electric pain-related evoked potential (PREP) techniques together with electroacupuncture, and the utility of using PREPs to capture and quantify acupuncture’s nociceptive effects.

Background The nociceptive system has been implicated in acupuncture analgesia, although acupuncture’s precise mechanism of action remains unknown. PREPs have emerged as an effective and reliable electrophysiologic method for evaluation of the human nociceptive system by electric stimulation of nociceptive Aδ and C fibers.

Design/Methods Seven healthy male and female volunteers underwent a previously designed electroacupuncture (EA) protocol using acupoints in the legs bilaterally, which has been demonstrated to induce systemic analgesia. Advanced PREP techniques involving tripolar stimulating electrode, varying interstimulus interval and incorporating a cognitive task during PREPs were used. PREPs were assessed prior to EA, during EA and 30 minutes after EA. Subjective pain perception in response to the PREP-related electric pain stimuli delivered to the non-dominant hand was assessed on the visual analog scale (VAS) at baseline, during EA and 30 minutes post-EA.

Results Reliable PREP N1, P1 and N2 waves were obtained from all subjects at the following average latencies: N1 = 131.5 msec, P1 = 189.4 msec, N2 = 231.1 msec. EA caused a significant reduction in PREP N1P1 wave amplitudes from 25.6 mcV to 15.4 mcV (p=0.006) and electric pain perception on the VAS - from 2.86 to 2.14 (p=0.008), compared to baseline. These effects were sustained at 30 minutes post-acupuncture with N1P1 wave amplitude 17.2 mcV (p=0.030) and VAS 2.28 (p=0.030), compared to baseline.

Conclusions Electroacupuncture causes significant changes in objective nociception, measured by PREP N1P1 wave amplitudes and in subjective nociception measured by the VAS and these effects are sustained for 30 minutes after EA. Planned future studies will involve chronic pain populations and will aim to assess acupuncture’s longer term analgesic effects.

Authors/Disclosures
Alexandra Dimitrova, MD (OHSU) PRESENTER	Dr. Dimitrova has nothing to disclose.
	No disclosure on file
	No disclosure on file
Jonathan Sisley (Oregon Health & Science University)	Mr. Sisley has nothing to disclose.
Barry S. Oken, MD, PhD, FAAN (Oregon Health & Science Univ.)	Dr. Oken has nothing to disclose.

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