Latent Structure Models & Statistical Foundation for TCM

1. Latent Structure Models & Statistical Foundation for TCM Nevin L. Zhang The Hong Kong University of Science & Techology

2. Latent Variables in TCM Theories • Symptoms • intolerance to cold, cold limbs, and cold lumbus and back, loose stools, indigested grain in the stool. • Syndromes • kidney yang deficiency, kidney yin deficiency, kidney essence insuficiency observed variables manifest variables latent variables

3. Where Do Latent Variables Come from? • Latent variables introduced by human brain to explain regularities that we observe • Example: lighting from nearby buildings • Regularity observed: • Lighting from several apartments were changing in synchrony • My first conclusion: must be a common cause • I did not see it. So, latent variable introduced. • What was the common latent cause? • The same TV channel. Interpretation of latent variable.

4. Conjecture of TCM Theory • Latent syndrome variables introduced to explain co-occurrence of symptoms. • Example: • Observed regularity • ‘intolerance to cold’, ‘cold limbs’, ‘cold lumbus and back’ often occur together • Latent variable introduced to explain the regularity • Kidney yang failing to warm the body

5. Experiences Human Brain Computer & Statistical Principles TCM Theory Model Match? Data Premise and Idea of the Latent Structure Approach Premise Idea: Reconstruct aspects TCM Theory via modern data analysis

6. Analysis of Kidney Data • Y0-Y34: manifest variables from data • X0-X13: latent variables introduced by data analysis

7. Model Match between Model and TCM Theory TCM Kidney yang deficiency, failing to warm body intolerance to cold, cold limbs, cold lumbus and back, • Spleen disorders  loose stools, indigested grain in the stool Good Match

8. Model Match between Model and TCM Theory TCM When kidney fails to control the urinary bladder, • frequent urination, urine leakage after urination, frequent nocturnal urination, • (in severe cases) urinary incontinence and nocturnal enuresis. Good Match

9. Model Match between Model and TCM Theory TCM kidney essence insufficiency premature baldness, tinnitus, deafness, poor memory, trance, declination of intelligence, fatigue, weakness, and so on. Good Match

10. Model Match between Model and TCM Theory TCM kidney yin deficiency  dry throat, tidal fever or hectic fever, fidgeting, hot sensation in the five centers,insomnia, yellow urine, rapid and thready pulse, and so on. Good Match

11. Kidney yang deficiency Kidney failing to control urinary bladder Kidney essence insufficiency Kidney yin deficiency X1 X4 X8 X10 Statistical Principle Match Data Significance of WorkStatistical Validation for TCM Theory • Supports objectivity of the syndrome factors kidney yang deficiency, … • Shows that statistical truths in TCM theory.

12. Experiences Human Brain Computer Model TCM Theory Data Significance of WorkModel-Based Diagnosis TCM Theory • incomplete, qualitative, vagueness Diagnois based on TCM theory: • Subjective, variability across doctors Model • Complete, quantitative, clear Model-based diagnosis • Objective, no variability across doctors