Deqi, a composite of unique sensations, is essential for clinical efficacy according to Traditional Chinese Medicine. It is described as a sensory perception of varying character and is mostly ascribed to metal needle acupuncture. However, it can also be elicited by different kinds of laser acupuncture stimulation. This short paper summarizes the current scientific status of deqi in laser stimulation. Different kinds of laser acupuncture are described in a comprehensive form, and the most interesting studies concerning deqi and laser acupuncture are presented.
In relation to acupuncture research, the term “deqi” is described as a sensory perception of varying character [
The literature search in the commonly used database PubMed yielded the results demonstrated in Figure
The PubMed literature search for the terms related to deqi. Note that, at the moment (Dec 3rd, 2012), there are only 3 articles mentioning deqi in connection with laser acupuncture [
This review article summarizes the current scientific status of deqi in laser acupuncture in a comprehensive form and is aimed at motivating the readers to perform more research on this very interesting topic for acupuncture.
Since ancient times, metal needles are the commonly used device for stimulating acupuncture points and eliciting a needle-specific deqi sensation. However, there are also new optical stimulation methods which were scientifically investigated for the first time by our research group within the last years [
Up to now, violet lasers are used only in special areas in medicine [
Violet laser needle acupuncture is a new optical method for stimulating different acupuncture points continuously and simultaneously. A wavelength of 405 nm, an output power of 110 mW, and a diameter of 500
Each single needle can emit a different wavelength. We used a continuous wave mode (CW). Due to coupling losses, the output at the tip of the needle is about 100 mW. Irradiation usually lasts 10 min (600 sec), and therefore, optical power density was very high (range: kJ/cm²) [
Violet laser acupuncture was made possible only due to latest inventions. Nakamura et al. [
The violet laser does not have similar penetration depth in human skin as, for example, the red or infrared laser described in the next subsection (violet: approximately 2 mm versus red/infrared: 2-3 cm [
“The first bichromatic laser needles (685 nm and 785 nm) were developed at the University of Paderborn, Germany (Dr. Detlef Schikora), and the first clinical investigations were performed in Lauenförde, Germany (Dr. Michael Weber). The first scientific experiments and publications on this field of research started in 2002 at our Medical University in Graz, Austria [
Multichannel laser needle acupuncture allows the simultaneous stimulation of individual point combinations (Figure
Different systems for laser acupuncture at the Medical University of Graz.
To the best of our knowledge, there are no studies concerning deqi and green laser or yellow laser. Green laser has a very low penetration depth and is suitable mainly for ear acupuncture or other superficial points. Yellow laser has not been used in acupuncture research up to now.
Deqi is described by patients and volunteers as heaviness or like an electrical current running along the treated meridians. If red (685 nm) or infrared (785 nm) lasers are used, the patients normally do not notice when the laser is started. So, in the beginning of the treatment, they also do not feel any deqi sensation. Several minutes later (5–10 min), many patients report a pleasant warm and sometimes vibrating feeling in some treated areas [
In an experimental pilot study, we found that violet laser stimulation increases temperature (mean ~1.5°C) and microcirculation (mean ~20%) at the acupoint Hegu (LI.4) significantly and immediately (1 min) after stimulation onset [
According to Traditional Chinese Medicine, one must first obtain deqi sensation for acupuncture to be effective. In some studies, we could demonstrate that initial stimulation with a metal needle is stronger than the initial stimulation with a laser, but it fades earlier (it is like a spike). Laser needle stimulation is initially not as strong as the metal needle stimulation, but it continues to rise throughout the entire treatment—and it can also elicit deqi sensation [
In a research article published in Evidence-based Complementary and Alternative Medicine, Beissner and Marzolff [
One limitation of our studies is that we did not quantify deqi sensation, for example, as a percentage of how many people felt deqi in laser versus metal needle acupuncture up to now. It is clear, however, that the percentage will be much smaller during laser acupuncture. At the moment, we also have no comparison of healthy volunteers versus patients on this topic.
Beside subjective and objective data that there is also a clear deqi sensation evoked by laser acupuncture, another related study published recently by our group is of particular interest [
The author declares to have no conflict of interests.
The scientific investigations were supported by the Stronach Medical Group, the German Academy of Acupuncture (DAA), and the Department of Science of the City of Graz. The study is part of the project “Evidence-based high-tech acupuncture and integrative laser medicine for prevention and early intervention of chronic diseases,” supported by the Austrian Federal Ministries of Science and Research and of Health and the Eurasia-Pacific Uninet. The author would like to thank Ms. Ingrid Gaischek, M.S. (Stronach Research Unit for Complementary and Integrative Laser Medicine, Medical University of Graz), for her valuable help in paper and figure preparation.