Application of neurophysiological methodology in acupuncture research
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Title: Application of neurophysiological methodology in acupuncture research. Background: Increased popularity and acceptance of acupuncture also increases demand for scientific evidence of its effectiveness. In order to produce such evidence acupuncture research borrows methods from other scientific disciplines. Thus it is essential to validate the usefulness of such methods when they are employed specifically in physiological research of the acupuncture phenomenon. Confirmation of physiological changes due to acupuncture stimulation could increase engagement in acupuncture research and make direct comparisons with biomedical research possible. Objectives: The main objective was to evaluate the usefulness of non-invasive neurophysiological methods in detecting physiological changes in response to manual acupuncture. It was not the purpose of this study to find a proof that acupuncture works or how it works, but to confirm that acupuncture can be successfully researched using objective, non-invasive neurophysiological methods. Method: A rigorously designed, randomised controlled trial (RCT) was used to evaluate the effectiveness of some of the neurophysiological research methods. Three-point criteria was set up. Firstly, to investigate if manual stimulation of the acupuncture points can induce physiological changes in healthy subjects that are strong enough to be detected by non-invasive testing methods. Secondly, to investigate if physiological changes induced by acupuncture stimulation form a pattern, which is unique for every individual acupuncture point being tested. And thirdly, to investigate if physiological changes induced by acupuncture are more pronounced in subjects initially showing stronger signs of subjective / objective stress. Overall, sixty healthy female subjects were recruited for the study, and one hundred and twenty experimental sessions were completed in order to collect the data. Objective measurements by means of multichannel computerised recording were used to capture concurrently occurring physiological events. Results: Acupuncture treatment used in group one (T1) using acupuncture point LU7 and in group three (T3) using acupuncture points LU7 and KD6 promoted deeper relaxation and light sleep in subjects showing higher levels of anxiety. In contrast, subjects in group two (T2) where only acupuncture point KD6 was stimulated, did not relax or easily fall into light sleep during the 40 minutes post-treatment. Usually Theta and Alpha “relaxation” waves were changed. Of the two treatment protocols T1 and T3, the T1 showed the strongest differences. This can be interpreted as indicating that acupuncture point LU7 promotes relaxation and light sleep. Stimulation of acupoint KD6 counteracted the relaxation effect promoted by acupoint LU7. Data from the experiments clearly showed that stimulation of two acupuncture points LU7 and KD6 did not influence heart beat in a strong way. The treatment effect was only detected in group T2 (acupoint KD6) where an increase in the sympathetic regulation may indicate that KD6 has a balancing and energising effect on heart rhythm. The respiration rate and respiration amplitude seems to be unchanged by acupuncture stimulation. There were no statistically significant differences in body temperature before and after the experiment. Systolic and diastolic blood pressure remained very stable and was not influenced by acupuncture stimulation of the two acupoints LU7 and KD6. Analysis of the electrodermal activity (EDA) data confirmed that changes in skin potential are very sensitive and specific to needle insertion and needle removal, but not specific to the site of the insertion. Physiological habituation seems to play significant role in diminishing the EDA response to manipulation of the acupuncture needle. Conclusion: Insertion of a single needle invokes physiological changes that can be detected by neurophysiological methods. Certain acupoint-specific patterns of change can be seen in multichannel recordings. Results suggest that neurophysiological methods are appropriate for, and can be adopted in acupuncture studies. Furthermore, recommendations regarding research designs were formulated. They include a strong need for a separate control group in acupuncture studies and highlight the importance of continuous monitoring of multiple physiological parameters during experiments of that type. New methods of data analysis based on neural networks gave very promising results that may rival traditional statistical linear models. Overall the outcome of this project may serve as a call for standardisation of neurophysiological research protocols in acupuncture laboratories.
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