Tongue inspection : a protocol to integrate neurology and traditional Chinese medicine

Introdução. A inspeção da língua (IL) é importante para o diagnóstico e prognóstico na Medicina Tradicional Chinesa (MTC). Os modelos de avaliação da língua variam nos diversos países, e não existe um modelo sistematizado. Objetivo: propor um modelo de avaliação sistematizada para a IL para ser utilizado em neurologia. Método. 1) revisão de livros em inglês, português, e espanhol, e artigos em inglês, português, espanhol e francês das bases de dados Pubmed, Lilacs, e Cochrane Library, usando as seguintes palavras-chave: língua, diagnóstico, prognóstico, medicina tradicional chinesa; 2) seleção das principais características da língua; busca por um protocolo de exame para a língua; busca por características relacionadas com avaliação de prognóstico de doenças. Resultados. foram encontrados 26 artigos; entretanto, nenhum deles apresentou perfil para o objetivo deste estudo, ou as informações eram imprecisas e vagas. O mesmo ocorreu com os livros ocidentais de MTC, nenhum deles apresentou um protocolo de exame. Assim, um protocolo de IL baseado na MTC foi elaborado, com quatro níveis de gravidade e complexidade. Conclusão. um protocolo sistematizado de IL foi elaborado para uso em medicina integrada (medicina ocidental e MTC), eliminando pontos divergentes e simplificando os itens a serem observados durante a IL.


INTRODUCTION
Tongue inspection (TI) is one of the most important diagnostic and prognostic methods in traditional Chinese medicine (TCM) 1 .Inscriptions regarding TI have been found carved on tortoise shells and bones dating from the sixteenth century BC.Ao Shi wrote the first specialized report during the Song dynasty (960-1279).Since 1949, an increasing number of research articles and books on tongue analysis have been published in China, some of which are still used in the country's education system 1 .
Several tongue evaluation models can be found in different countries, but a systematic protocol is lacking.Various classification systems for tongue lesions have been proposed in Western medicine; however, consensus has not been reached to date.In addition, the fact that the etiology of certain conditions is unknown hinders the development of a standard classification system 2 .The association of the tongue with neurological diseases has been the object of research by several authors.Multiple case reports have related diseases to certain tongue features.For instance, a relationship between macroglossia and amyotrophic lateral sclerosis (ALS) was reported in a study with two patients 3 .This is particularly relevant because the typical finding in ALS is tongue muscle atrophy by demyelination of hypoglossal nerve fibers 3 .Both patients had comorbidities that could explain the enlargement of the tongue based on the TCM theoretical framework (hypothyroidism, diabetes mellitus, gastroesophageal reflux, and vitamin B12 deficiency) 4 .Fasciculations have also been pointed as an important feature in the early diagnosis of ALS, especially when they involve muscles such as the tongue 5 .The exchange of information between Western and Chinese medicine could provide answers and a possibility of treatment for macroglossia, thus reducing patient suffering.
In TCM, motor neuron diseases are related to atrophic syndrome, which is termed Wei 痿, in Chinese.The description and diagnosis of this syndrome include tongue characteristics (TCs), especially color and coating, based on literature descriptions 6 .
A study comparing mice with a mutation for dystonia musculorum and mice without that mutation showed that the tongue of the mice with the mutated gene had smaller fungiform papillae and fewer taste buds, which suggested that those structures are affected by dystonin 7 .The fungiform papillae appear as reddish dots on the tongue, a feature that is pathophysiologically correlated with dystonia musculorum according to TCM.In another study, the density and size of fungiform papillae were found to be reduced in knockout mice with inactivated BPAG1 locus (dystonin), which results in dystonia musculorum 8 .Dystonin deficiency was shown to reduce the number of taste buds and fungiform papillae in the anterior portion of the tongue 7 .
Several neurological diseases can progress to increased or decreased numbers of papillae (eg.Machado--Joseph disease, Stüve-Wiedemann syndrome, familial dysautonomia, dystonia musculorum, and Behçet's disease) due to insufficient or excessive neurotrophic support 8 .
There are some difficulties with tongue analysis.A study in collaboration with TCM experts to evaluate inter-and intrapractitioner agreement regarding tongue inspection revealed many mistakes and discordant interpretations.It also showed that the definitions found in the literature were vague and inadequate 9 .
Nevertheless, Zhang published their experience in training TCM practitioners, thereby increasing the level of agreement 10 .He had identified the variability in diagnostic standards among practitioners of TCM in previous studies (2004 and 2005), which underlines the need for standardization and training to improve the performance of TCM practitioners.
In 2003, our research team initiated a study on the potential application of TCM techniques in neurology, especially for diseases such as ALS and postpolio syndrome.However, we found multiple difficulties in the discussion of the study results.Among the many obstacles, there was a lack of TI standards -a key element in the assessment of TCM results.During that early stage of the research, we conducted a case study addressing the use of acupuncture in Brazilian para-athletes with refractory pain.After acupuncture treatment, the overall pain index improved; however, one athlete did not respond to the treatment.This athlete had a pathological tongue, and we considered the possibility of further aggravation, such as the progression of poliomyelitis (the athlete's underlying disease) to postpolio syndrome due to acupunc-original ture treatment failure and the tongue alterations we had found.A few years later, this athlete died as a result of rapidly progressive liver cancer 11 .
We proceeded to work on a way to standardize the characteristics and concepts and to organize the TCs according to symptom severity.We found that the literature on the subject was inaccurate in describing TCs.Very often, the information imparted to the students relied on the empirical knowledge of the instructors.Even today, there is a paucity of literature on TI in the West, and the existing literature is based on textbooks and lacking standards.In addition, the atlases with tongue pictures available in the West bring information for specialists only, hence, of no utility to professionals trained in Western medicine.Therefore, in order to advance the studies conducted by our team, it was necessary to design an instrument to standardize the evaluations and define severity criteria regarding TCs from the Western perspective.
The present review is part of a research project including the systematized evaluation of three groups of patients (control, postpolio syndrome, and ALS), which will be reported in a future article.
This review of the literature was conducted to gather the information that supported the design of an instrument to assess TCs, the standardization of the clinical data that were collected thereof, and the conceptualization of all the aspects included in the examination protocol.Many of these concepts were taken from textbooks available in Portuguese and English in Brazil, and some were constructed based on the experience of investigators with training in TCM and neurology.Thus, the selected characteristics are those considered to be relevant to neurological clinical practice, particularly in regard to diseases involving the motor neuron system.In addition to introducing a useful instrument for research, the present study aims to facilitate the exchange of this body of knowledge with the other health professions.To that end, we have addressed TI according to the TCM theory and translated it into the language of Western medicine.
The objective was to propose the systematization of TI for use in research and in multi-and cross-disciplinary care.

METHOD
The project as a whole was approved by the UNIFESP Research Ethics Committee (Protocol No. 0760/11).
1.A review of books printed in English, Portuguese, and Spanish, and a review of the scientific literature indexed in the Pubmed, Lilacs, and Cochrane Library databases in English, Portuguese, Spanish, and French until May 2012, using the following descriptors: tongue, diagnosis, prognosis, traditional Chinese medicine.
2. Selection of the major TCs and respective prognostic descriptions.
3. Development of a systematic examination protocol; selection of tongue features to be described and appraised for inclusion in a systematic clinical examination according to criteria obtained from the literature review, empirical expertise in TCM, and neurological knowledge.The data were described and organized in increasing levels of chronicity and severity based on TCM theory.

RESULTS
We selected 3 books [12][13][14] and 26 papers (Table 1).They were assigned to three categories: tongue inspection (17 papers); aspects of tongue, normal or otherwise (7  papers); the tongue as a diagnostic or prognostic parameter (6 papers).Ten papers were used in the text 1,9,10,15- 17,19,21-23 .This classification allowed us to analyze 1) a systematic model of tongue inspection; 2) information regarding the description of normal TCs, and 3) information concerning prognostic features, in chronological order or increasing degrees of severity.

TCM textbooks
We searched all the textbooks on the subject available in Brazil and selected two books in Portuguese and one in English [12][13][14] to inform the construction of the protocol.This choice was based on the fact that those books are recommended by the acupuncture and TCM schools in Brazil, and thus can serve as parameters of the information that is being provided by the schools.Furthermore, we believe it is important to study the terms in Portuguese and compare them with the international literature.For that reason, one of the books is an English translation of a Chinese book.We used the most recent editions available in Brazil.What follows is the wealth of information gleaned from the textbook review.

Tongue inspection
The review focused on eight items observed during tongue inspection.Three authors referred to lighting as an important factor to be noted in TI, but their descriptions differ [12][13][14] .The key is to find natural lighting (cited by all).However, Yamamura 13 adds the possibility of using cold light, while Maciocia 14 mentions incandescent light, full--spectrum fluorescent lighting, or tungsten lamps.
The extension of the tongue is also addressed by these authors, with the following specifications: it should be natural 12 , relaxed 12,13 , outstretched without excessive force 14 .
Maximum tongue exposure time is only mentioned by Maciocia 14 whereas food consumption issues are cited by another author 12 .All three authors mention food intake that changes the tongue color, e.g.dyes, while the possibility of cleaning the tongue is referred to by only one author 12 .The use of medication can also alter the examination results, as mentioned by the three authors [12][13][14] .

Tongue characteristics
The characteristics of the tongue described as normal or abnormal are not clear.Moreover, tongue description involves subjective evaluations based on individual experience.In consonance with Kim 6 , who examined nine TCM texts and five TCM journals, we found inadequate, unclear, vague descriptions, or no tongue description at all.

Normal tongue characteristics
The normal TCs are listed in Table 2. "Vitality" is only mentioned in one book on tongue inspection 14 .
Normal tongue coating is described as "white and thin" by Fei 12 and Maciocia 14 , while for Yamamura 13 it should be "slightly moist and shiny, with homogeneous distribution, and translucent".
Fei 12 describes the normal color of the tongue body as "light red and fresh".To Yamamura 13 , it is "rosy and bright", and Maciocia14 describes it as "pale red and fresh".
Moisture is described as "a thin film of saliva, resembling a wet tongue," or as "slightly moist, not too dry or too wet," or simply "wet".
Movement was also described differently by those authors.Fei 12 defines it as "flexible and agile", Yamamura 13 refers to normal movement as "good mobility", and Maciocia 14 describes it as "flexible, not too flaccid and not too stiff, not trembles or shudders when stretched, not rigid or immobile involuntarily".
Only Fei 12 addresses the issue of normality of taste on examination.Yamamura 13 describes normal size as "proportional to the size of the mouth" while Maciocia 14 defines it as "not increased nor thin".

Abnormal tongue characteristics
The three books describe TI under two major headings, body and coating, but the subheadings are different for all of them [12][13][14] .

Tongue coating
Coating had 70 citations, 53 of which were made solely once.Only five catetories were cited by three authors (Table 3).These types of coating are 1) white and thin; 2) yellow; 3) mildewed white; 4) gray, and 5) black.The descriptions are rich in adjectives."Mildewed white", for example, is described as "snowflake-like or congee-like white spots" 12 , "thick white granules of cheese" 13 , or "(moldy) thick and irregular in distribution, such as beancurd or crumbled cottage cheese, non-adherent" 14 , ambiguous or inaccurate descriptions that can be misleading.In general, the books divided coating into color and quality.Quality includes thickness, type, and moisture.Regarding coating color, there are no illustrations or color chart.The same occurs with the colors of the tongue body.The authors include major types, but they establish associations with other features that they consider important, which increases the number of coating subtypes without providing a clear description.This occurs, in general, with all TCs described in the three books.
We found 44 terms describing the color of the tongue body.Fei 12 cites seven types and describes five; Yamamura 12 , 22/4, and Maciocia 14 , 27/18.As with tongue coating, there are many associations of color with other features of the tongue.Basically, there are four tongue body colors: pink, red, purple/blue, and pale pink.Only two categories were cited by three authors: pale and red (Table 3).
Fifteen items are listed under "size".Fei 12 cites seven and describes two; Yamamura 13 , 11/3, and Macio-cia 14 , 7/5.Four items are cited by all authors, but with different descriptions.Four categories were cited by three authors: enlarged, enlarged and red, enlarged and pale, and thin (Table 3).There is no description of parameters to evaluate tongue size.
Under "movement", 35 items are listed.Fei 12 cites only one and does not describe it.Yamamura 13 cites 34 and describes 12; Maciocia 14 mentions five, but does not describe any.We excluded 31 types of movement that were mentioned by a single author.Only one category was cited by three authors: deviated tongue (Table 3).
Regarding "shape and aspect", 31 items were found, including cracks, tooth marks, spots, dots, stretching, consistence, ulcers, and some peculiar aspects such as cerebellar or hammer tongue.Fei 12 cites seven items and describes three; Yamamura 13 , 11/9; Maciocia 14 , 24/18.There were only three code 3 items: tooth marks, cracks, and ulcers.We excluded 23 types that were mentioned by a single author (Table 3).
Fifteen items were listed for "dots".Fei 12 cites one, but offers no description.Yamamura 13 cites 15 and describes 13, and Maciocia 14 cites three, with one description.Only one item was common to all three texts; however, it was not described (Table 3).We excluded 12 types mentioned by only one author.Besides the color, the location of the dots on the tongue surface is another important aspect to the authors.Only one item was cited by three authors: red dots [12][13][14] .

Disease prognosis
All the authors refer to evaluation of prognosis and disease course related to tongue coating and body color [12][13][14] .Normal coating is white and turns yellow with internal heat.It becomes thick if there is damp or phlegm.Coating turns yellow with the progression of internal heat, and orange, brown, or black in severe cases.
Color can also range from pink (normal) to red in cases of heat or yang, and deep red with worse conditions.Purplish hues appear with stasis by heat or cold, and pale in cases of yang or blood deficiency.3. Characteristics of tongue coating according to citation and agreement between books (authors Fei 12 , Yamamura 13 , and Maciocia 14 ).

TCM journals
We found 82 articles correlating tongue, diagnosis, prognosis and TCM, most of them in Chinese.We selected 26 articles referring to "tongue inspection according to TCM"; however, none of those papers outlines a protocol.No article defines or describes the features of the tongue, although these pieces of information can be found in the textbooks on the subject.This can be seen in the articles analyzing the concepts of the TCs, which also referred to the books (Table 1).
Regarding TI, there is consensus in the literature about the subjectivity of the exam 15,16 .In view of this, some papers describe developing techniques for image capture and computerized analysis of the tongue to attenuate subjectivity.One reason for this could be the methodology of TCM schools, which is based on an ancient tradition with a different model of teaching and learning.Another likely explanation is the reasoning process of tongue diagnosis in TCM.It seems to be a multifaceted and continuous process, with a systematic evaluation of the tongue and consistent diagnostic procedures 16 .However, the aim of the present study was to construct a protocol for practitioners and non-practitioners of TCM to identify disease severity regardless of symptoms, and determine prognosis.Therefore, items such as the map of organs on the surface of the tongue were not included, and the analysis was not related to TCM syndrome diagnoses.
We found seven papers on characteristics of the tongue; however, we located no description of the characteristics.Two studies focused on a healthy population and the prevalence of normal and abnormal characteristics 17,38 .The aim of several studies was to correlate the presence of abnormal TCs with some syndromes and diseases 19,21,39 .
There are some studies about disease prognosis 22 .Color and coating are considered to be important prognostic features in cancer 22 , lung cancer 19 , and rheumatoid arthritis 23 .Thickness is mentioned in one study 19 ; this is an important component of TI, and we believe that it can be very useful in monitoring patients undergoing any type of therapeutic intervention.However, the evolution of TCs and the relationships between other features remain unclear.It could also identify patients at risk for sudden aggravation of their condition.In our outpatient clinic, we study neurological diseases with progressive neuromotor dysfunction.
In Eastern medicine, studies are advancing toward an objective assessment of the TCs, as several researchers have published their results with the use of images obtained from spectrometry or computerized analisys (Table 1).Unfortunately, this technology is not available in Brazil yet.Nevertheless, we understand that direct clinical examination is of great utility and can be easily performed after proper training.It is necessary to enhance communication in order to facilitate the dialogue between the two models of medicine -TCM and Western -by adapting the language and establishing concepts and standards for the items to be evaluated, including parameters of normality.
To perform good quality TI, some parameters have been established and are described as follows:

Systematic TI method
The standards comprise the following items: 1. Examiner: The analyses are to be performed by a single TCM-trained professional with expertise in tongue inspection or specific training.
2. Environment: Light-colored walls, preferably white, are recommended.Cold white or natural lighting should be aimed directly at the tongue.
3. Positioning of the examinee: The individual should be in a sitting position, relaxed, breathing softly and naturally, preferably in a lower position relative to the examiner and facing them.
4. Staining substances: The presence of staining substances on the examinee's tongue requires the tongue evaluation to be adjourned.Guidelines on solid food, drinks, and cigarettes must be included.
5. Tongue scraping: If tongue scraping was performed before the analysis, the exam should be repeated at a different time with the recommendation not to scrape the tongue prior to examination.
6. Guidelines on tongue exposure: Patients were instructed to "Please, show your tongue."If any clarification was needed, the individuals were asked to "Please, relax your tongue, and show it one more time," or "Please expose your tongue a little bit further."In those instances, although certain patients needed to exert significant strength to expose the tongue, they were advised not to contract the tongue extensively to avoid compromising blood flow.
7. Time of tongue exposure: The tongue shoul not be exposed outside of the oral cavity for periods longer than 10 seconds.If a new observation is necessary, the tongue should be withdrawn to allow relaxation, followed by new exposure.This approach will avoid long exposure times.

Tongue analysis systematization
Tongue analysis was systematized according to the items described in the literature, and organized using TCM theory and empirical expertise to create a scale of increasing complexity of physiological changes (vertical axis, y) and increasing severity of TCs (horizontal axis, x).Six variables were assigned to the vertical axis, and five degrees to the horizontal axis.
The horizontal axis includes information concerning degrees of severity and prognosis.The exact sequence in which the TCs appear and their temporal relationship is still unknown.In view of this, the x axis construction was based on the TCM theory of depths of disease, which describes levels, or layers, where the affection arises, from the most superficial to the deepest layer, with increasing depths meaning worsening disease status.These layers (from superficial to deep) are the following: Wei Qi, Qi, Yin, Xue, and collapse of Yin and Yang (Jing).Then completed, from left to right, with TCs corresponding to their respective level of impairment.The first degree is related to the normal aspect, with mild and superficial impairment (Wei Qi and Qi), followed by characteristics associated with a disturbance of Yin and Xue (Blood), which have moderate severity, and ending in the collapse of Yin and Yang, or Jing deficit (fifth degree), of marked severity or chronicity.Thus, each grade corresponds to a change in severity level.

Y-axis variables (vertical)
The core characteristics of the tongue were distributed in categories along the vertical axis.Most of these characteristics were cited in the three textbooks.Some features, such as movement and normal size, were included because of their great importance in neurology, according to the empirical experience of the authors.The description or definition of the terms for the present protocol was the result of the literature review combined with the empirical experience of the specialist team-professionals with background in TCM and clinical experience of more than 10 years (Figure 1).The characteristics were described below.
1. Moisture: Tongue moisture was considered normal when a thin coating of saliva was present without fully covering the papillae.The tongue should have a glossy appearance, and upon touching, one should feel the saliva and moisture but should also still be able to feel the roughness of the surface imparted by the papillae.
Certain patients affected by neuromuscular diseases can present excessive moisture, which cannot be attributed to excessive saliva, since,upon deglutition, the saliva coating remains thick, fully covering the papillae.In such cases, upon touching the tongue, one should ex-original pect to feel this moisture as well as the smooth, slippery surface of the tongue.The most chronic condition is associated with the absence of fluids and a dry tongue.This condition should give the impression of a lack of saliva and a dry feeling to the touch.
2. Coating: Thin coating, by definition, consists of a thin, whitish layer that allows the observation of the tongue surface and its papillae.Individual coating grains are not normally observed.Thick coating differs from thin coating by presenting itself as a single-layered coating on the papillae, as an agglomerate, or as an actual layer covering the surface of the tongue.It may be present on the entire surface or in localized regions.The coating can be clearly and unmistakably observed.
This coating can present a whitish, gray, or yellowish color with different levels of intensity, ranging from orange to green or dark shades.The perception of the color can depend on the cosmetics (e.g., lipstick) used by the patient, the color of the examination room, and the lighting.Therefore, environmental standardization is important.Coating may be absent at different stages of severity.In this case, the tongue presents itself to the naked eye as a smooth and shiny surface.
Tongue scraping can partially remove thin coating and, on occasion (albeit more difficult), certain Normal moisture: A thin film of saliva covering the surface without fully covering the papillae.The surface is glossy; upon touching, one should feel the presence of saliva (and moisture) and the roughness imparted by the papillae.Normal size: The tongue does not extend beyond the dental arch limits by more than one-third of its size.Normal movement: Ease of movement without straining the facial and cervical muscle groups.Centered, without abnormal movement, and remaining firm and relaxed without signs of stiffness or contraction.
variants of thick coating.When a history of tongue scraping is discovered, the analysis should be repeated after advising the patient not to perform this action.
3. Color: Pink color, although classified as normal, may be difficult to characterize because it can vary from pale pink (the most serious condition) to different shades of red.The standard color pattern was determined based both on image reproductions of the tongue analysis atlas and on the examiners' clinical experience.The comparison of images containing pink or red colors allows for a clear distinction of shades.The shade classified as normal from the analysis of the photographic records obtained in the outpatient clinic is presented in Figure 1.
Color chart was obtained from tongue photographs (Figure 2).Color may vary in the different tongue topographies.In certain cases, several shades of color are present in the same tongue, with different implications, although the shade indicating the most serious condition is the one to be considered.
In such cases, however, all observed shades should be reported.The color purple was highlighted in the systematic analysis due to its implications (i.e., stasis), which can have a sudden and aggressive course and can be life--threatening.Even in lighter shades, the color purple can be readily identified.twhich were highlighted in the tongue systematic analysis, are defined as a circumscribed area where the color differs from the predominant shade on the tonguebody.They can vary in size, shape, color, and location.They indicate stasis.5. Fasciculation is defined as the involuntary and repetitive movement (twitching) of the resting tongue in the oral cavity.

X-axis variables (horizontal)
The construction of the protocol relied on the results gathered from the literature review, taking into account the items described most frequently by the three authors consulted.The items to be evaluated are listed in the rows.In each categorie, from left to right, the distribution follows the concept of depth of disease.It starts at "normal" followed by changes in the Qi 氣, Yang 陽, Yin 陰, Xue 血, and lastly Jing 精氣deficiency.The order is also an attempt to organize the concepts, beginning with the normal patterns followed by excess, and finally, deficiency patterns.Three groups were formed: normal, chronic impairment, and chronic impairment difficult to reverse.The resulting model is shown in Figure 1.Tongue aspects and characteristics are showed in Figure 2.

CONCLUSION
A systematic protocol of tongue inspection was prepared to be used in integrative medicine.
The systematization of clinical tongue evaluation a necessity in research, and could be a useful instrument in the evaluation of health and disease states in a comprehensive and dynamic manner to highlight certain characteristics, differentiate between groups, and compare results.

ACKNOWLEDGMENTS
We thank Wu Pi Chun for ranslating the Chinese language studies and Eneida de Souza Bulle Oliveira for the translation and her work in the waiting room alongside our therapist, Heloísa Soares Hungria.We are also grateful to physical educator Celso Antonio de Souza Mello and physiotherapist Bruna Terumi Sato Yonamine for their invaluable contributions.This study was conducted with volunteers who received no monetary compensation.
4. Size: The size of the tongue was evaluated relative to the dental arch.Size can be classified as normal when the tongue does not extend beyond the dental arch by one-third of its size.If the exposed tongue surpasses that limit by more than one-third of its size, it can be considered an enlarged tongue.Similarly, small or thin tongues are defined as those smaller than the dental arch, with the tongue being classified as atrophic when the exa miner can observe abundant free space within the boundaries of the dental arch, or when the tongue presents wrinkling associated with a loss of mass or shape.
5. Movement: Movement was standardized on the basis of normal tongue exposure.Normal movement is defined as easy, without straining the facial or cervical muscle groups, centered, without abnormal movement, with the tongue remaining relaxed and firm, with no stiffness or contractions.A deviated tongue is defined as any deviation of the exposed tongue from the midline.A tremor (quivering) is defined as any involuntary, intermittent movement with small amplitude that does not hinder speech or swallowing.Random movements are described as rare in the reviewed literature; they resemble amoeboid movements.They are involuntary and constant, and serve no specific function.Small exposureis characterized as ineffective tongue protruding movement despite the effort in performing that movement.If exposure does occur, it is only partial, at the expense of great muscular effort, and for a short period of time.Tongue tremors and deviations from the midline are also regarded as "red flags" and were highlighted in the systematic analysis.They can be related to energy fluctuations (internal wind), which may lead to acute ca ses of varying severity requiring medical intervention.
6. Other findings: Several different characteristics observed in abnormal tongues were pooled in this group.1. Red dots result from increased blood flow toward the fungiform papillae, giving the tongue a darker shade of red. 2. Tooth marks are the persistent impression left by the dental arch on the edges of the tongue, which persist even after the tongue is relaxed and exposed outside of the oral cavity.3. Fissures can present as cracks in the surface of the tongue in a transverse, horizontal, or diagonal orientation.The term "fissure" is exclusively used for cracks inhe midline, regardless of their size.4. Spots,

Figure 1 .
Figure 1.Tongue analysis systematization according to TCM. original

Figure 2 .
Figure 2. Tongue characteristics according to the systematized examination protocol.

Articles Year of publication Category* Summary Tongue-related information
18Evaluates healthy individuals and analyzes the frequencies of alterations in TCs in that populationDoes not define or explain the parameters and evaluation method Su W et al, 2011182,3 Analyzes digital photos qualitatively and quantitatively relative to such parameters as tongue body color, coating color, coating thickness No description of parameters; uses specialized equipment for image capture Lim KS et al, 2009 19 2 Investigates the presence of tongue signs related to bulbar alteration in a sample of normal individuals, including deviated tongue, central furrowing, increased grooving of the tongue and uneven/irregular border, fasciculations and tongue tremor; no central furrowing, increased grooving or fasciculation were observed Describes some abnormal movements of the tongue based on a neurology textbook Lin SC et al, 2008 20 3 Analyzes signs and symptoms of Yin deficiency according to the Society of Integrated Chinese and Western Medicine in China in patients with cancer and rates them based on severity, with an assessment of four-month survival rates; relates tongue parameters to Yin deficiency and to the survival rates of those patients Lists characteristics linked to prognostic assessment in patients with cancer; does not describe or define concepts or the evaluation methodology *Categories: 1 = tongue inspection model; 2 = tongue characteristics; 3 = tongue characteristics and prognosis

Table 1 .
The 26 selected articles referring to tongue inspection according to traditional Chinese medicine -TCM.

Table 2 .
Normal tongue characteristics and corresponding descriptions according to the textbook review

Maciocia 14 Agreement Description
*Cited and with author agreement; 0 = not cited; + = cited; Y= Yes; N = No Two or more authors cited the listed items We excluded 53 types of coating cited by a single author We excluded 35 types of color mentioned by a single author Rev Neurocienc 2014;22(2):201-214 original