Building medical dictionaries for patient encoding systems: A methodology

Abstract

One of the most critical problems of automatic natural language processing (NLP) is the size of the medical dictionaries. The set of compound medical words and the often used possibility to create new terms render the exhaustivity of medical dictionaries beyond question. The structure of such dictionaries is usually composed of two parts: the first one generally contains morphological and sometimes syntactical information necessary to identify, on a grapheme level, a given word in a sentence whereas the second part is often devoted to conceptual knowledge associated with the recognised word. It is only when these two prerequisites are fulfilled that an attempt to understand the meaning of a whole expression is possible. The approach developed in this paper shows the pragmatic method used to implement a powerful analyser dedicated to help physicians or coding clerks to encode medico-economic information about patients using international classifications like ICD. It describes how to build medical dictionaries that can help the application of morphological and conceptual analysers (encoders). The methods used have proved to be efficient for various classifications as well as for multiple languages as the system presently supports French, German, English and Dutch for the full ICD-10 classification.