by Eric Brand

In a previous blog, I mentioned the research on tongue diagnosis in Taiwan that is orchestrated by my teacher Dr. Chang Hen-Hong. Dr. Chang is the head of the Chinese medicine division at both Chang Gung Memorial Hospital and Chang Gung University, and he is a key leader in the field of Chinese medicine. While Dr. Chang is involved with many research projects, one of his most significant contributions relates to Chinese medical tongue diagnosis.

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As the leader of Chang Gung’s Chinese medical division, Dr. Chang has been able to make a lot of groundbreaking research possible. For example, he established Taiwan’s national adverse event reporting system for Chinese medicine, which remains the most comprehensive and advanced model for TCM adverse event reporting in the world. (Read more about global trends in adverse event reporting here)

Just as the national adverse event database offers unprecedented access to scientific information on herbal usage and adverse reactions, Dr. Chang’s research on tongue diagnosis is truly pioneering. Dr. Chang is launching one of the largest-scale research projects on tongue diagnosis in the history of Chinese medicine. After years of researching the details of everything from pixels and lighting to expert opinion on diagnostic standards, his research is moving forward into ever larger dimensions.

Following the completion of the current early studies, they will implement digital tongue images into tens of thousands of digital patient files via the hospitals digital TCM records. Once thousands of tongue images (along with the corresponding diagnosis and herbal therapy for that patient) are in the system, Chang Gung will be able to analyze the data and tongue changes. In this way, they will be able to truly create an evidence base that allows them to see, for example, whether or not thick tongue fur is consistently associated with a clinical presentation of dampness, and whether or not it responds to damp-resolving therapies. The cases can be analyzed based on a staggering variety of parameters, so one can assess, say, the prevalence of a red-tipped tongue in patients with a specific ICD-9 code or specific TCM disease name. This is truly the type of data collection that is the mother of all Evidence-Based Medicine in TCM.

So I was looking through my notes the other day, and I came across a powerpoint presentation that I translated for Dr. Chang years ago. It had some really interesting data on one of the early studies. I’d like to share some of the details.

Basically, they started by creating standard conditions for the viewing of the tongue. To minimize confounding variables, elements such as the distance, light, and color of the surroundings must be standardized. Prior research in Taiwan had shown that the temperature of the tongue varied in different regions (for example, the heart/lung area was cooler than the spleen/stomach and liver/gallbladder areas), so having an even temperature in the room is important as well. A variety of studies have been carried out with digital tongue photography in Taiwan, and all of them aim to minimize distortions in color and other variables.

So after deciding on the camera and lighting standards, they created standard operating procedures for how the patient’s tongue should be extended and other details. The colors were analyzed with a very cool digital color scheme so that they could be grouped into three groups, basically depending on a spectrum from pale to red to dark, deep purple-red. A team of specialists from mainland China and Taiwan was consulted to establish standards of consensus on the “map” of the tongue (as to organ regions).

Next, 58 healthy visitors, 60 diabetic patients, 97 patients with chronic hepatitis, and 40 patients with osteoporosis were analyzed based on their tongue color and texture. While it was only a single, small, and preliminary study, they found the following interesting findings:

In the healthy visitors, they found:

white coating 67.2%
light red tongue body 48.3%
teethmarks 60.3%
no “cinnabar speckles” (red papilla) 48.3%
no stasis speckles (yu dian) 84.5%
no stasis macules (yu ban) 67.2%
no central crack 67.2%
patients without many cracks in the tongue 62.1%

In the patients with chronic hepatitis, they found:
Only 31.7% lacked cinnabar speckles (red papilla), compared to 48.3% of the healthy group

In the patients with osteoporosis, they found:
52.5% of the patients with osteoporosis had many cracks in their tongue, while only 37.9% of healthy patients had many cracks. The osteoporosis group also tended to have pale tongues. In this study, the tongues were grouped into three big categories with nine subcategories in total. The three big categories were basically tending pale, tending normal red to pure red, and tending dark, purple, and deep red, but with differentiation based on both a color chart and traditional TCM terminology.

In the diabetic patients, 27.8% had pale tongues, and only 25.8% had slightly red (healthy). By contrast, the 48.3% of the healthy patients had slightly red (healthy) tongues.

Cool stuff! I can’t wait until they have 20,000 patient files in the computer to analyze. Already they are doing sophisticated analysis on trends in medicinal use, so once the tongue is in there, it would be amazing. Just think, how many patients with such and such ICD-9 codes have red tongues, and what percentage of those patients were prescribed shi gao? How many 29 year old women have red tongues, menstrual pain, and consume jia wei xiao yao san? How many of them get better? Wow, it boggles the mind how many ways you could look at it. Fun stuff, EBM and TCM.

By the way, we have another blog on EBM and TCM here