Is there an effect of acupuncture an the resting EEG?

Author(s): Griffiths, P., Bacon, P., Gravill, N.

Journal/Book: Complementary Therapies in Medicine. 2001; 9/2: 77-81.

Abstract: Objective: To investigate if acupuncture has a measurable effect an the resting EEG. Subjects: I 4 healthy volunteers with no neurological condition took part in the study. Methods: Using a digital storage EEG recorder and quantitative frequency analysis techniques data were obtained before, during and after acupuncture stimulation.To minimize the effect of artefacts all data were collected with the subject alert, but with eyes closed. Manual stimulation of the LI 4 acupuncture site was undertaken for periods of 0.5, I .0 and 2.0 min. Frequency analysis of the EEG data from each acupuncture event was compared to the baseline data to show any significant changes over the bandwidth 0.3 to 30 Hz. Only changes greater than 2 standard deviations were considered significant. Results: In I 0 subjects the frequency spectra remained unchanged during acupuncture, but in three significant increases were recorded in the amplitude of very low frequencies between 0.5 and 2 Hz and in one subject there was an increase in the amplitude of the alpha band during acupuncture. All spectra returned to their baseline values immediately after acupuncture. Outcome: The changes recorded in the delta band of individuals during acupuncture were large but highly variable.They arose at a frequency that is an the limit of the recording equipment and where recording and physiological artefacts are known to occur, although there was no evidence of artefactual contamination of the data.The one case in which there was an increase in the alpha band is attributed to suppression of the dominant rhythm initially brought about by anxiety concerning the procedure which subsequently disappeared during acupuncture as the subject relaxed. Conclusion: It is clear that there are no changes brought about by acupuncture in the resting EEG in the frequency range 2-30 Hz and no evidence to attribute changes below 2Hz to a direct affect of acupuncture.

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