Thermography and acupuncture

Acupuncture is a technique from traditional Chinese medicine involving the insertion of fine needles into specific points or regions of the body.

This technique has always sparked much debate and discussion within the scientific and medical community because it is based on the belief that the body has energy channels called meridians through which “qi” or vital energy flows. Furthermore, assessing its effects and mechanisms has led to the search for objective methods to measure and better understand acupuncture.

In this context, infrared thermography has emerged as a promising tool for studying acupuncture, allowing for an objective and real-time assessment of changes in the skin’s surface temperature associated with the stimulation of specific acupuncture points. This combined approach of acupuncture and thermography offers new insights into better understanding the therapeutic effects of acupuncture and its clinical application.

Acupuncture

Acupuncture, a practice with at least 2,000 years of history originating in China as part of traditional medicine, has been used to initiate and facilitate the flow of qi, considered the vital energy circulating along the body’s meridians. It is believed that stagnation or lack of qi can cause illness, and unblocking it can alleviate symptoms such as pain and lack of energy.

Despite its widespread use, the effects of acupuncture have not yet been fully scientifically demonstrated. As it moved into Western medicine, doubts arose about its effectiveness and mechanism of action, especially in a context where evidence-based medicine has become predominant. Clinical research on this matter has been controversial, with debates over the efficacy of sham acupuncture as a control, as there may be psychological influences at play.

Thermography and Acupuncture

To address this issue, some researchers have used thermometry to visualize the electromagnetic waves emitted by the body during acupuncture. It has been observed that the thermal reaction during real acupuncture is different from that of sham acupuncture or absence of manipulation. Agarwal-Kozlowski et al. (2009) conducted a study focusing on the importance of the Hegu acupuncture point in the treatment of various disorders, highlighting its role in initiating the “de-qi” phenomenon. “Sham acupuncture” locations on the hand where no acupuncture points are described in traditional Chinese medicine were chosen to compare thermographically monitored skin responses. The study evaluated temperature changes at specific points on the hands before, during, and after needle insertion. Points on the fingertips and halfway along the metacarpal bones were analyzed, both on the right and left hand of each test subject.

Subjects were randomly assigned to one of four groups:

1. Without manipulation
2. Acupuncture in Hegu (with acupoint)
3. Cutaneous acupuncture (without acupoint)
4. Muscle acupuncture (without acupoint)

Figure 1. Thermograms from the research (4 different days) during 30 min.

Main Study Results

To quantify these differences, subjects were divided into five subgroups based on the observed temperature change. The greatest temperature difference was detected at 10 minutes after needle insertion, so this point was used to compare differences between and within groups.

The results showed that in the no manipulation group, 70% experienced a decrease in surface temperature, while in the acupuncture group, only 6% showed a decrease. Instead, 46% of the test subjects in this group experienced a temperature increase greater than 1.5°C.

These findings demonstrate that acupuncture at Hegu induces a significant increase in surface temperature compared to no acupuncture or sham acupuncture.

Fig. Graphical representation of temperature over time. Temperature at Hegu needling (red line), absence of needling (orange line), cutaneous (blue line), and muscular (dark line).

Infrared thermography emerges as a valuable tool for distinguishing the effects of acupuncture, as seen in the example of the discussed study. Thermography allows for easy and real-time detection of changes in surface temperature, providing an objective way to evaluate outcomes.

The findings of this study suggest that acupuncture at the Hegu point led to a significant increase in surface temperature, while sham acupuncture and absence of manipulation resulted in a decrease. These results could have important implications for clinical practice and future acupuncture research, especially in terms of understanding underlying physiological mechanisms and differentiating between real and sham acupuncture. However, further research seems necessary to evaluate the exact role of the sympathetic nervous system, endogenous opioid release, and functional magnetic resonance imaging in acupuncture.

Conclusions

• Infrared thermography emerges as a promising tool for studying the effects of acupuncture, allowing for an objective evaluation of clinical outcomes.
• Infrared thermography facilitates the distinction between real and sham acupuncture by detecting changes in surface temperature associated with needle insertion at specific points.
• The implementation of infrared thermography in acupuncture research provides significant advantages, such as easy manipulation, real-time visualization, and increased sensitivity to detect subtle temperature changes.
• Studies using infrared thermography have shown that acupuncture at specific points, such as Hegu, produces a significant increase in surface temperature, suggesting physiological activation in the treated area.
• Infrared thermography offers an objective way to evaluate the effects of acupuncture, overcoming reliance on patient statements and providing a more precise understanding of the underlying mechanisms of therapy.

References

Cai, W., Chen, A. W., Ding, L., & Shen, W. D. (2019). Thermal effects of acupuncture by the infrared thermography test in patients with tinnitus. Journal of acupuncture and meridian studies, 12(4), 131-135.

Ovechkin, A., Lee, S. M., & Kim, K. S. (2001). Thermovisual evaluation of acupuncture points. Acupuncture & electro-therapeutics research, 26(1-2), 11-23.