Auricular acupuncture has been described in ancient China as well as Egypt, Greece, and Rome. At the end of the 1950s, ear acupuncture was further developed by the French physician Dr. Paul Nogier. The goal of this study was to develop a new system for ear acupressure (vibration stimulation) and to perform pilot investigations on the possible acute effects of vibration and manual ear acupressure on heart rate (HR), heart rate variability (HRV), pulse wave velocity (PWV), and the augmentation index (AIx) using new noninvasive recording methods. Investigations were performed in 14 healthy volunteers (mean age ± SD:
The Chinese have provided an ancient explanation of traditional acupuncture based on the principle of energy flow around the body in channels called meridians. This energy flow, called “Qi,” can be out of balance. Inserting acupuncture needles or stimulating acupoints using acupressure can reestablish harmony.
Using technology from western medicine, one can clearly measure the effects of acupuncture and acupuncture-like stimulation in the brain and periphery [
Auricular acupuncture has been described in ancient China as well as Egypt, Greece, and Rome [
The goal of this study was to develop a new system for acupressure (vibration stimulation) and to perform pilot investigations on possible acute effects of vibration and ear acupressure at the “heart” ear acupoint on HR, HRV, PWV and AIx in a group of healthy volunteers using new noninvasive recording methods.
Two different methods were used for stimulating the “heart” ear acupoint. The first method uses a pen with a special electronic device inside. With this pen, mechanical vibration stimuli can be administered at a frequency of about 30 Hz. The tip of the equipment is made of stainless steel (material no. 4301) and has a diameter of 2 mm and a length of 7 mm (see Figure
New instruments for acupressure (vibration) stimulation used in ear acupuncture at the “heart” acupoint.
An HRV medilog AR12 (Huntleigh Healthcare, Cardiff, UK, and Leupamed GmbH, Graz, Austria) system was used for electrocardiographic (ECG) monitoring. The system is designed for a monitoring period of more than 24 hours. The sampling rate of the recorder is 4096 samples per second. Therefore, R-waves can be detected accurately. All raw data are stored digitally on a 32-MB compact flash memory card. After removing the card from the portable systems, the data can be read by an appropriate card reader connected with a standard computer. The R-peak time resolution is 244 microseconds, and the
HRV is measured as the percentage of change in sequential chamber complexes called RR-intervals in the ECG. The registration of HRV is performed using three electrodes (Skintact Premier F-55; Leonhard Lang GmbH, Innsbruck, Austria) on the chest (cf. Figure
The measurements took place in the lab of the TCM Research Center in Graz at the Medical University of Graz (with permission of all medical doctors and volunteers).
The methods for determining arterial stiffness and wave reflection parameters were noninvasive. The measurements were performed with a cuff applied to the brachial artery (cf. Figure
AIx describes the influence of the reflected pulse wave on systolic pressure (in percent of blood pressure amplitude) [
Within this study, 14 healthy volunteers (9 females, 5 males) with a mean age ± standard deviation (SD) of
Measurement profile. Ear vibration and manual ear acupressure were performed for 30 sec each. The measurement points for wave reflection and arterial stiffness are indicated with a–d.
None of the volunteers were taking any medication. All volunteers were informed about the nature of the investigation as far as the study design allowed. The study was approved by the local ethics committee, and all volunteers gave their written informed consent.
The volunteers laid on a bed in our lab (see Figure
Acupressure stimulation was performed at the “heart” acupoint. This acupoint is one of the most important ear acupuncture points and is commonly used in patients with hypertension [
Data were analysed using Friedman repeated measures ANOVA on ranks (SigmaPlot 11.0, Systat Software Inc., Chicago, Ill, USA). Post hoc analysis was performed with Tukey test. The level of significance was defined as
Figure
(a) mean heart rate (HR). (b) total heart rate variability (HRV total). Box plot illustrations of 14 healthy volunteers are shown. Note the significant differences. The ends of the boxes define the 25th and 75th percentiles with a line at the median and error bars defining the 10th and 90th percentiles. The different measurement phases and points (a–d) are indicated (cf Figure
Furthermore, the biosignal monitoring during acupressure (vibration) and manual acupressure showed substantial increases in the LF frequency band (Figure
(a) LF (low frequency)/HF (high frequency) ratio. (b) the LF (low frequency) band of HRV. Note that the median of the LF parameter increases during ear acupressure vibration and during manual ear acupressure in 14 subjects. For further explanation, see Figures
A typical example from the new software analysis is shown in Figure
Frequency analysis of heart rate variability. Note the appearance of the influence of blood pressure modulation (
Systolic blood pressure (BPsys), diastolic blood pressure (BPdia), and mean arterial pressure (MAP) of the 14 healthy volunteers during the different phases (a–d). For further explanation of the box plots, see Figure
Figure
(a) brachial augmentation index (AIx) in %, describing the influence of the reflected pulse wave on systolic pressure (in percent of pulse pressure) of the 14 healthy volunteers during measurement phases a–d (see Figure
Auricular acupuncture is used for various autonomic disorders in clinical practice in western and eastern medicine. Recently, there is a growing focus on the important role of the brain, and, therefore, there is also a need to explain how acupuncture and acupuncture-like stimulations affect the cerebral autonomic function. There is strong evidence from previous animal and human studies that acupuncture impacts the autonomic nervous system. There are two important publications from Gao et al. [
The second study from Gao et al. was published recently in 2011 in Brain Research [
Experimental studies concerning ear acupuncture-like stimulation at the “heart” acupoint in humans are rare. In a Chinese study, the authors investigated 30 patients with hypertension. A comparison of the hypotensive short-term effects between the “heart” ear point and another point of ear needling showed that there was a marked hypotensive effect associated with stimulation of the “heart” point [
In 1993, Zhou [
Concerning our present study, it is important to point out that the RR-intervals in the ECG are controlled by the blood pressure control system, which is influenced by the hypothalamus and, in particular, by the vagal cardiovascular centre in the lower brainstem [
In the present study, HR decreased significantly and HRV total increased during both ear acupressure and ear vibration (compare Figure
The present study also includes a new application of the innovative oscillometric technique for measuring arterial stiffness in the field of acupuncture. As of May 2011, only six scientific articles concerning “arterial stiffness and acupuncture,” “wave reflection and acupuncture,” and “pulse wave velocity and acupuncture” could be found in the scientific literature [
Scientists from Austria, China, Japan, Mexico, and Taiwan (alphabetical order) performed these studies.
The PWV and AIx increase in somewhat different ways in parallel with the aging process, and they provide different information regarding the arterial vascular status [
However, there are some limitations of this pilot study. The number of subjects was small (
Ear acupuncture has been used for medical treatment for thousands of years. A large amount of empirical data is available, but the quantification of the effects on the brain and the periphery has not previously been possible. Using modern biomedical techniques, changes in vital parameters can now be quantified in a noninvasive way. Modernisation of acupuncture at the Medical University of Graz [
The following conclusion can be drawn from the results of this study: HR decreases and HRV total increases significantly during ear acupressure and/or ear acupressure vibration. The velocity of the pulse wave between the aortic root and the bifurcation of the aorta decreases markedly (yet insignificantly), whereas the augmentation index increases immediately after acupressure vibration and manual acupressure at the “heart” auricular acupoint. Our hypothesis as stated in the Discussion will require future investigation for verification.
The scientific investigations were conducted within the project “Bioengineering and clinical assessment of high-tech acupuncture—A Sino-Austrian research pilot study” (Austrian Ministries of Health and of Science and Research) and were supported by the Science Department of the City of Graz and the Jubiläumsfonds of the Austrian National Bank (project 13463). The measurements were performed within the research areas of “Sustainable Health Research” and “Neuroscience” at the Medical University of Graz. The first author, Associate Professor X.-Y., Gao, MD, PhD, was supported by a Eurasia Pacific Uninet scholarship. The results have been presented by her at the Transcontinental Symposium “Basic Research Meets High-Tech Acupuncture and Moxibustion” on May 31th, 2011 in Beijing organised by the China Academy of Chinese Medical Sciences Beijing and the TCM Research Center at the Medical University of Graz. X.-Y., Gao, L. Wang, and G. Litscher contributed equally in this paper.