The Tarsqi Toolkit’s Recognition of Temporal Expressions within Medical Documents

Abstract

To diagnose and treat patients, clinicians concern themselves with a complex set of events. They need to know when, how long, and in what sequence certain events occur. An automated means of extracting temporal meaning in electronic medical records has been particularly challenging in natural language processing. Currently the Tarsqi Toolkit (TTK) is the only complete software package (open source) freely available for the temporal ordering of events within narrative free text documents. This project focused on the TTK’s ability to recognize temporal expressions within Veterans Affairs electronic medical documents. A baseline evaluation of TTK’s performance on the Timebank v1.2 corpora of 183 news articles and a set of 100 VA hospital admission and discharge notes showed an F-measure of 0.53 and 0.15, respectively. Project development included the correction of missed and partial recognition of temporal expressions, and the expansion of its coverage of time expressions for medical documents. Post-modification, the TTK achieved an F-measure of 0.71 on a different set of 100 VA hospital admission and discharge notes. Future work will evaluate TTK’s recognition of temporal expressions within additional sets of medical documents.