| Summary: | 碩士 === 南華大學 === 自然醫學研究所 === 95 === A randomized controlled clinical trial was conducted to assess the change of autonomic nervous system (ANS) by ultrasonic stimulations of the acupoints. Specifically, ultrasound frequencies of 1 and 3 MHz associated with different duty cycles of the tone burst wave at different acoustic power were employed to stimulate the Shenmai (BL 62) and Zhaohai (KI 6) acupoints on subjects’ left foot according to the yin-yang theory in the Chinese medicine meridian system. Blood pressure (BP) and parameters of heart rate variability (HRV) were measured to evaluate the change before and after the stimulation. A total of 110 healthy volunteers were randomly allocated to two acupoint groups, each with six subgroups of different treatments which include circular massage (no ultrasound wave), sham (no ultrasound wave), 1MHz continuous wave ultrasound, 3MHz continuous wave ultrasound, 1MHz pulsed wave ultrasound, and 3MHz pulsed wave ultrasound.
Results from paired t-test or Wilcoxon signed-rank test, ANCOVA and standardized percentage change showed that the physiological effect such as systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean heart rate (MHR) were not significantly different between subgroups in the Zhaohai and the Shenmai group. In time-domain and frequency-domain analyses, the Standard Deviation of Normal to Normal Interval (SDNN), Total Power (TP) and high frequency power (HF) were not significantly different between subgroups in the Zhaohai and the Shenmai group. When analyzing with standardized percentage change, significant differences were found in Lower Frequency Power (LF) (p＝0.013), normalized lower frequency (nLF) (p＝0.023), and LF/HF (p＝0.009) between subgroups within the Zhaohai group.
Overall, the 3MHz wave ultrasound groups were more effective than the 1 MHz groups. Contrast to the acupuncture reinforcing effect of continuous wave ultrasound, the pulsed wave ultrasound showed the possibility of reducing effect. The circular massage group (without ultrasound wave) seemed to exhibit placebo effect in heart rate variability. In conclusion, this study demostrated that ultrasonic stimulation on Zhaohai and Shenmai acupoints could lead to a beneficial effect on the autonomic nervous system. The findings can provide leads for further investigations of using ultrasonic acupuncture.
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