The Study on the Agreement between Automatic Tongue Diagnosis System and Traditional Chinese Medicine Practitioners

Abstract

Tongue diagnosis is an important practice in traditional Chinese medicine (TCM) for diagnosing diseases before determining proper means of treatments. Traditionally, it depends solely on personal knowledge and experience of the practitioner, thereby being criticized as lacking of objectivity. Currently, no research regarding intra- and inter-agreements of automatic tongue diagnosis system (ATDS) and TCM doctors has been conducted. In this study, the ATDS is developed to extract a variety of tongue features and provide practitioners with objective information to assist diagnoses. To evaluate the ATDS clinical stability, 2 sets of tongue images taken 1 hour apart from 20 patients with possible variations in lighting and extruding tongue, are employed to investigate intra-agreement of the ATDS, intra-agreement of the TCM doctors, and the inter-agreement between the ATDS and TCM doctors. The ATDS is shown to be more consistent with significantly higher intra-agreement than the TCM doctors (kappa value: 0.93 ± 0.06 versus 0.64 ± 0.13) with P < 0.001 (Student's t-test). Inter-agreements between the ATDS and TCM doctors, as well as among the TCM doctors are both moderate. The high agreement of the ATDS can provide objective and reliable tongue features to facilitate doctor in making effective observation and diagnosis of specific diseases.

Figures

Figure 1

Illustration of tongue image capturing with the ATDS.

Figure 2

The processing flow of ATDS analysis.

Figure 3

A snapshot of the computerized tongue diagnosis questionnaire.

Figure 4

Samples of 20 matching pairs of tongue images, the upper and lower tiers of images are taken from the same patients separately at a one-hour interval.

Figure 5

Classifications of fur color and fissure as well as judgment of tooth mark are affected by the length of extruding tongue for the same patient. (a) Long extruding and (b) short extruding tongue.

Figure 6

Classifications of saliva and red dots are affected by the image-taking angle between the tongue and camera.

Figure 7

Judgment of tooth mark is affected by different image-taking angle and the length of extruding tongue.

Figure 8

Tongue shape is adversely influenced by the extruding force applied on the tongue.

Figure 9

Calibration of image color using the color bar accompanied with the ATDS to make image quality consistent for images taken at difference circumstances. Note that the x-axis and y-axis of the plots shown on the third row denote gray level and frequency, respectively.