Learning for Medical Concepts Speaker: Shih-Han Lo Advisor: - - PowerPoint PPT Presentation

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Learning for Medical Concepts Speaker: Shih-Han Lo Advisor: - - PowerPoint PPT Presentation

Multi-layer Representation Learning for Medical Concepts Speaker: Shih-Han Lo Advisor: Professor Jia-Ling Koh Author: Edward Choi, Mohammad Taha Bahadori, Elizabeth Searles, Catherine Coffey, Michael Thompson, James Bost, Javier Tajedor-Sojo,


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Speaker: Shih-Han Lo Advisor: Professor Jia-Ling Koh Author: Edward Choi, Mohammad Taha Bahadori, Elizabeth Searles, Catherine Coffey, Michael Thompson, James Bost, Javier Tajedor-Sojo, Jimeng Sun Date: 2017/10/31 Source: KDD ’16

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Multi-layer Representation Learning for Medical Concepts

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Outline

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 Introduction  Method  Experiment  Conclusion

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Introduction

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 Motivation

Ars Technica

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Introduction

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 Purpose

 Learn interpretable representations.  Enable clinical applications to offer more than just

improved performances.

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Introduction

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 Framework Electronic Health Records (EHR)

Code- and visit-level representations

Med2Vec

Input Output Proposed algorithm

  • r method
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Introduction

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Introduction

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 EHR structure

 The set of all medical codes:  Sequence of visits: where  The goal of Med2Vec is to learn two types of

representations:

 Code representations  Visit representations

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Outline

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 Introduction  Method  Experiment  Conclusion

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Method

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 Med2Vec architecture

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Method

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 Learning from the visit-level representation

 We minimize the cross entropy error as follows:

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Method

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 Learning from the code-level representation

 The code-level representation can be learned by

maximizing the following likelihood.

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Method

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 Unified training

Function (3) Function (2)

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Method

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 Interpretation of learned representations

 Code representations

 Non-negative matrix factorization (NMF) 

 Visit representations

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Method

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Outline

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 Introduction  Method  Experiment  Conclusion

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Experiment

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 Datasets

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Experiment

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 Evaluation strategies

 Code representations

 Qualitative evaluation by medical experts  Quantitative evaluation with baselines: NMI

 Visit representation

 Predicting future medical codes  Predicting CRG level  Baselines: One-hot+, SA, Skip-gram+, GloVe+

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Experiment

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 Results

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Experiment

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 Results

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Experiment

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 Results

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Experiment

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 Results

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Outline

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 Introduction  Method  Experiment  Conclusion

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Conclusion

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 We proposed Med2Vec for learning lower

dimensional representations for medical concepts.

 Med2Vec incorporates both code co-occurrence

information and visit sequence information of the EHR data.