Abstract not found

The European GALEN project is developing terminology services based on a large, re-usable medical ontology. The ontology is being built using GRAIL, a description logic with transitivity and general concept inclusions.

Despite years of work, no re-usable clinical terminology has yet been demonstrated in widespread use. This paper puts forward ten reasons why developing such terminologies is hard. All stem from underestimating the change entailed in using terminology in software for ‘patient centred ’ systems rather than for its traditional functions of statistical and financial reporting. Firstly, the increase in scale and complexity are enormous. Secondly, the resulting scale exceeds what can be managed manually with the rigour required by software, but building appropriate rigorous representations on the necessary scale is, in itself, a hard problem. Thirdly, ‘clinical pragmatics ’ – practical data entry, presentation and retrieval for clinical tasks – must be taken into account, so that the intrinsic differences between the needs of users and the needs of software are addressed. This implies that validation of clinical terminologies must include validation in use as implemented in software. Why-is-terminology-hard-single-r2.doc 14/01/00 15:21 2 1.

Concept models, or ‘ontologies’ represented in description logics are becoming central to many efforts in re-usable medical terminologies. Developers of any ontology must make a series of choices concerning how concepts are represented. These choices are made more difficult by the limitations of the logical formalisms in which ontologies are represented and the complexity of the pragmatics of medical usage, as well as by the sheer size and scope of medicine. Principles for ontology structure to guide developers are still poorly. This paper articulates the principles arrived at from the experience of the GALEN programme and illustrates them with an overview of the its ontology, the GALEN Common Reference Model. The complete Common Reference Model and associated material is available from the OpenGALEN foundation at www.OpenGALEN.org

GALEN technology for re-usable terminologies using formal classification is being applied to the creation and maintenance of a reference terminology for drugs. GALEN's techniques are being used to address specific deficiencies of existing drug classifications that make it difficult to create and maintain guidelines to support prescribing in the care of patients with chronic diseases.

Controlled medical vocabularies are useful in application areas such as medical information systems and decision-support systems. However, such vocabularies are large and complex, and working with them can be daunting. It is important to provide a means for orienting vocabulary designers and users to the vocabulary's contents. We describe a methodology for partitioning a vocabulary based on an IS-A hierarchy into small meaningful pieces. The methodology uses our disciplined modeling framework to refine the IS-A hierarchy according to prescribed rules in a process carried out by a user in conjunction with the computer. The partitioning of the hierarchy implies a partitioning of the vocabulary. We demonstrate the methodology with respect to a complex sample of the MED, an existing medical vocabulary. Keywords: Controlled Medical Vocabulary, Object-Oriented Modeling, Ontology, Semantic Network, Partitioning 1

GALEN seeks to provide re-usable terminology resources for clinical systems. The heart of GALEN is the Common Reference Model (CRM) formulated in a specialised description logic. The CRM is based on a set of principles that have evolved over the period of the project and illustrate key issues to be addressed by any large medical ontology. The principles on which the CRM is based are discussed followed by a more detailed look at the actual mechanisms employed. Finally the structure is compared with other biomedical ontologies in use or proposed.

Objective: Controlled medical terminologies (CMTs) have been recognized as important tools in a variety of medical informatics applications ranging from patient-record systems to decisionsupport systems. CMTs are typically organized in semantic network structures consisting of tens to hundreds of thousands of concepts. This overwhelming size and complexity can be a serious barrier to their maintenance and wide-spread utilization. In this paper, we propose the use of object-oriented databases (OODBs) to address the problems posed by the extensive scope and high complexity of most CMTs for maintenance personnel and general users alike. Design: We present a methodology that allows an existing CMT, modeled as a semantic network, to be represented as an equivalent OODB. Such a representation is called an ObjectOriented Healthcare Terminology Repository (OOHTR). Results: The major benefit of an OOHTR is its schema which provides an important layer of structural abstraction. Using the high-level view of a CMT afforded by the schema, one can gain insight into the CMT's overarching organization and begin to better comprehend it. Our methodology is applied to the Medical Entities Dictionary (MED), a large CMT developed at Columbia-Presbyterian Medical Center. Examples of how the OOHTR schema facilitated updating, correcting, and improving the design of the MED are presented. Conclusion: The OOHTR schema can serve as an important abstraction mechanism for enhancing comprehension of a large CMT, and thus aids in usability. 1