Temporal classification of medical events

  • Authors:
  • Preethi Raghavan;Eric Fosler-Lussier;Albert M. Lai

  • Affiliations:
  • The Ohio State University, Columbus, Ohio;The Ohio State University, Columbus, Ohio;The Ohio State University, Columbus, Ohio

  • Venue:
  • BioNLP '12 Proceedings of the 2012 Workshop on Biomedical Natural Language Processing
  • Year:
  • 2012

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Abstract

We investigate the task of assigning medical events in clinical narratives to discrete time-bins. The time-bins are defined to capture when a medical event occurs relative to the hospital admission date in each clinical narrative. We model the problem as a sequence tagging task using Conditional Random Fields. We extract a combination of lexical, section-based and temporal features from medical events in each clinical narrative. The sequence tagging system outperforms a system that does not utilize any sequence information modeled using a Maximum Entropy classifier. We present results with both hand-tagged as well as automatically extracted features. We observe over 8% improvement in overall tagging accuracy with the inclusion of sequence information.