Knowledge Representation of Discharge Summaries

Abstract

A Natural Language Processing system for discharge summaries has been implemented, and gives promising results in the restricted domain of Digestive Surgery. Syntactical analysis is strongly driven by semantical information according to the idea of “proximity processing”. From the recognition of semantical components in the free text sentences, a knowledge representation is built in the form of concepts and relationships as defined by Sowa and his conceptual graphs. The concepts are retrieved from the text according to predefined conceptual graphs, to be considered, at a first glance, as a sort of knowledge frame, specifying the mandatory and allowable relationships to other concepts, as well as default values necessary to solve possible ambiguities. The final knowledge representation is independent from the initial text, even when synonym expressions are present, in which case they are mapped into a unique representation.

The system is currently being tested “in vitro” and should undergo a careful evaluation before considering field tests. Furthermore, the completness of the knowledge base has not yet been achieved. The system is implemented for the French language; however it could, of course, be rewritten for other languages like English or Italian, for example.