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Strive-Achievement Traditional Chinese Tongue Diagnosis Applied in Western Medicine
Background The tongue diagnosis is one of the most important diagnostic tools of traditional Chinese medicine (TCM). It dates back to the Shang Dynasty (1600 B.C.–1000 B.C.). Practitioners of TCM believe that the tongue’s appearance can show a lot about someone’s health. Tongue appearance is not used as a diagnostic tool by itself; it is a part of the complete medical assessment.
The Components of Tongue Diagnosis TCM is a very subjective diagnosis. There are many different TCM schools that have their own point of view on the tongue diagnosis. Also, TCM diagnoses are not applicable in Western medicine because of the unique words used to describe the disease. Following are examples of some of different interpretations by TCM practitioners. Practitioners of TCM observe the tongue’s color, thickness and surface. According to them, normal tongue is pale red, not cracked, not thicker or thinner than normal for that individual and has a white, thin, almost transparent coating. Sublingual veins should not be dark, varicose or distended. According to TCM, the normal tongue shows free flow of energy and blood, proper function of the stomach and balanced yin and yang. According to Chinese philosophy, there are two fundamental principles: yin is dark, cold, wet and passive and yang is bright, hot, dry and active. Balance of these two principles is necessary for health. A tongue that is thicker than normal indicates an excess of yin, which in turns indicates obstruction of transport and movement of water and fluids in related organs. A thinner-than-normal tongue indicates insufficiency of blood, yin and qi. By Chinese philosophy qi is a “life force”, a vital energy that is part of every living thing. If the tongue is pale, it points to lack of blood flow in the corresponding organ, and a redder tongue points to heat in a specific organ. A blue color tongue indicates cold, while purple or dark red color indicates blood stasis in correlated organ. Brownish, blue or black spots on the corresponding zone of the tongue would indicate blood stasis in the viscera. Varicose sublingual veins would point to blood stasis in the chest. Red tip of a tongue would be interpreted as excessive heat in the heart, while red sides of a tongue would represent heat in the liver-gallbladder. Tongue coating is associated with the function of stomach; for example, if the coating is thicker than normal for that individual, it means that the stomach is not digesting food properly, and the food is backing up. Thicker and dry coating of the tongue represents dysfunction of the stomach, such as imbalance of intestinal fluids or digesting process. Yellow coating points to pathological heat in the corresponding organ, which in TCM is one element of what Western medicine calls inflammation. Black coating points to a more serious condition of the viscera. Tongue diagnosis is very subjective. Observation is subject to environmental factors such as light source and brightness, and the accuracy of the diagnosis also depends on the practitioner’s level of experience. Many different research studies have been conducted with the goal to make tongue diagnosis more objective, scientific and applicable as a quantitative diagnostic tool.[1]
In 1985, Anhui Traditional Chinese Medical College and the University of Science and Technology of China performed the first experiment based on the quantitative analysis of tongue color. The study used a charge-coupled device (CCD) as an optical sensor to measure the levels of redness, greenness and blueness (“RGB model”) in tongue images. The results indicated the potential for tongue diagnosis to become a qualitative analysis.[1] In tongue diagnosis, characteristics of the coating of the tongue, such as color, thickness and texture are very important. In 2000, Chiu used computerized tongue examination system (CTES) to carry out a research that can recognize structural texture of the coating such as: color, luster, thickness and if coating is grimy or crusted. This method involved measuring various optical properties of tongue images to determine properties of the coating of the tongue. The aim of this method was to decrease the effects of the environment, in order to improve the accuracy of diagnostic results. This was accomplished by using well-controlled hardware. The results of the CTES were compared with physicians’ diagnoses, and the agreement was high, at over 86%, supporting the argument that tongue diagnosis could be made to become objective.[2] TCM relates sublingual veins directly to the heart, the kidney, the liver and the viscera. Healthy sublingual veins are bluish purple, moist and without varicosity. In TCM, diagnosis of any changes in the sublingual veins is very subjective. These changes are thought to represent blood stasis in related organs. In 2002, Chiu, Lan and Chang proposed a more objective way to assess the blood stasis in sublingual veins as a representation of blood stasis in other organs. They compared several features of sublingual veins: maximum length, length ratio between the veins and tongue body, maximum width, the proportion of normal width, the area of the veins, vein color, and the symmetry information for the sublingual veins.[1] The results showed that proportion of the maximum to average width of the sublingual veins is a relevant indicator of blood stasis. This research provided additional proof that there is a great potential to develop a computerized technique for using TCM tongue diagnosis in an objective and scientific way.[1] Many studies were undertaken to make TCM diagnosis by means of the tongue better understood by Western medicine and modern biomedicine. Most of them had weaknesses: either they were limited to syndromes applicable only in TCM, or results were validated only by subjective opinion of TCM practitioners.[3] One study attempted to apply modern biometric techniques to connect the quantitative features of the tongue with one of three diagnostic categories: normal, pancreatitis and appendicitis. In the research, samples of tongue images were collected and reviewed by TCM practitioners. Quantitative measurements were calculated and, finally, useful features were chosen. The tongue was found to have distinctive characteristics in each of the diagnostic categories. In appendicitis, the tongue is light red, red or dark red, with thick white or yellow coating, and it has pronounced red spots on the tip. In pancreatitis, the tongue body is bluish or bluish purple. These results proved that, based on tongue appearance and by using specific quantitative features and textural measurements, disease can be diagnosed.[3]
In 2005, Pang, D. Zhang, and Wang took a different approach to tongue diagnosis. Their tongue-computing model (TCoM) featured several characteristics intended to overcome certain limitations from of previous investigations. First, TCoM was concerned about the connection between the quantitative tongue features and specific disease (in this research, it was appendicitis) (Figure 2) and not just symptoms. Second, results were validated by objective Western medicine instead of subjective TCM practitioners. Third, a group of 912 tongue samples was selected from 12,000 patients, while previous research included no more than 120 patients. These features made the results more applicable to Western medicine.[4]
For thousands of years Traditional Chinese Medicine practitioners have been examining the tongue first, by a simple procedure, which is a part of the complete medical assessment. Practitioners make their diagnostic connecting relations, which made the tongue a valuable representation of what may be occurring elsewhere in the body. Traditional tongue diagnosis has attracted attention of modern medicine and biomedicine, and researchers are trying to develop a computerized method of TCM tongue diagnosis4 that addresses its limitations, including its subjectivity and its variability due to light source and brightness. Traditional tongue diagnosis is not making diagnosis of the specific disease, but making a connection between the pathological changes on tongue surface and the symptoms of disease.[3] TCoM, proposed in 2005, is the breakthrough in making traditional tongue diagnosis more clinically applicable. It is the first method connecting changes in tongue appearance with the disease as it is determined by Western medicine. This method will speed up the modernization of traditional tongue diagnosis and its clinical application.[4] It also proves a great evolution of science; gaining knowledge from the past and applying it to the technologies of today. Being particularly applicable in the dental office, this method, once scientific research has been conducted to prove its validity in practice, may help in early detection of many diseases. Imagine if we could take pictures of our patients’ tongues, load them onto a computer and analyze them to determine if patient needs a referral to a specialist. This could prove an additional avenue for dental hygienists to demonstrate their value in serving their practice and their patients through preliminary diagnosis.
Jelena Karcas was born in the Republic of Serbia. She is a senior dental hygiene student at the New York University, an active student member of ADHA and a representative for her dental hygiene class. She is very passionate about prevention, early detection and helping patients.
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By
Jelena Karcas
In
TCM, the tongue is considered an external organ because, most of the time,
it is in contact with the air. It is believed that different zones of
the tongue reflect the condition of the different organ systems (Figure
1). Traditional Chinese medical practitioners usually look at the entire
tongue coating, shape and color, before they concentrate on the specific
zones of the tongue.
