title: Reliability and validity of tongue color analysis in the prediction of symptom patterns in terms of East Asian Medicine.
abstract: OBJECTIVE
  To examine whether color parameters of tongue inspection (TI) using a digital camera was reliable and valid, and to examine which color parameters serve as predictors of symptom patterns in terms of East Asian medicine (EAM).
  
  
  METHODS
  Two hundred female subjects' tongue substances were photographed by a mega-pixel digital camera. Together with the photographs, the subjects were asked to complete Yin deficiency, Phlegm pattern, and Cold-Heat pattern questionnaires. Using three sets of digital imaging software, each digital image was exposure- and white balance-corrected, and finally L* (luminance), a* (red-green balance), and b* (yellow-blue balance) values of the tongues were calculated. To examine intra- and inter-rater reliabilities and criterion validity of the color analysis method, three raters were asked to calculate color parameters for 20 digital image samples. Finally, four hierarchical regression models were formed.
  
  
  RESULTS
  Color parameters showed good or excellent reliability (0.627-0.887 for intra-class correlation coefficients) and significant criterion validity (0.523-0.718 for Spearman's correlation). In the hierarchical regression models, age was a significant predictor of Yin deficiency (β = 0.192), and b* value of the tip of the tongue was a determinant predictor of Yin deficiency, Phlegm, and Heat patterns (β = - 0.212, - 0.172, and - 0.163). Luminance (L*) was predictive of Yin deficiency (β = -0.172) and Cold (β = 0.173) pattern.
  
  
  CONCLUSIONS
  Our results suggest that color analysis of the tongue using the L*a*b* system is reliable and valid, and that color parameters partially serve as symptom pattern predictors in EAM practice.
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: Park
authors.forename: Jin-Moo
authors.initials: JM
authors.lastname: Lee
authors.forename: Seung-Yeon
authors.initials: SY
authors.lastname: Yoo
authors.forename: Young-Bae
authors.initials: YB
authors.lastname: Park
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003116:Color; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008518:Medicine, East Asian Traditional / Q000379:methods*; D008875:Middle Aged; D011795:Surveys and Questionnaires; D014059:Tongue / Q000737:chemistry*; D016710:Yin Deficiency / Q000175:diagnosis*; D055815:Young Adult