Knowledge Representation and Management: Towards Patient Health Self-management.

OBJECTIVES: To summarize excellent current research in the field of knowledge representation and management (KRM). METHOD: A synopsis of the articles selected for the IMIA Yearbook 2012 is provided and an attempt to highlight the current trends in the field of health management is sketched. RESULTS: Among the five selected papers, two confirm the benefit of exploiting open-source language toolkits for the automatic extraction of medical concepts, assertions and/or relationships from clinical texts. One paper aims at exploiting domain-specific terminologies to improve the parsing of biomedical noun phrases, and another one aims at discovering rare diseases associations embedded into disparate textual sources. Finally, the last paper describes a collaborative search approach integrated into a homegrown EHR search engine. CONCLUSIONS: This selected set of papers confirms that natural language processing, as well as knowledge extraction, discovering and retrieval, are still active and fruitful research fields. Although these papers are not directly focusing on personal health informatics applications,, important features are highlighted and tailored to fit the requirements of patient health self-management. Delivering timely, friendly and secure access to functional, accurate, up-to-date and sustainable personal health records is a significant challenging task for supporting self-managed healthcare.

Knowledge representation and management: benefits and challenges of the semantic web for the fields of KRM and NLP.

OBJECTIVES: To summarize excellent current research in the field of knowledge representation and management (KRM). METHOD: A synopsis of the articles selected for the IMIA Yearbook 2011 is provided and an attempt to highlight the current trends in the field is sketched. RESULTS: This last decade, with the extension of the text-based web towards a semantic-structured web, NLP techniques have experienced a renewed interest in knowledge extraction. This trend is corroborated through the five papers selected for the KRM section of the Yearbook 2011. They all depict outstanding studies that exploit NLP technologies whenever possible in order to accurately extract meaningful information from various biomedical textual sources. CONCLUSIONS: Bringing semantic structure to the meaningful content of textual web pages affords the user with cooperative sharing and intelligent finding of electronic data. As exemplified by the best paper selection, more and more advanced biomedical applications aim at exploiting the meaningful richness of free-text documents in order to generate semantic metadata and recently to learn and populate domain ontologies. These later are becoming a key piece as they allow portraying the semantics of the Semantic Web content. Maintaining their consistency with documents and semantic annotations that refer to them is a crucial challenge of the Semantic Web for the coming years.

Knowledge representation and management: transforming textual information into useful knowledge.

OBJECTIVES: To summarize current outstanding research in the field of knowledge representation and management. METHOD: Synopsis of the articles selected for the IMIA Yearbook 2010. RESULTS: Four interesting papers, dealing with structured knowledge, have been selected for the section knowledge representation and management. Combining the newest techniques in computational linguistics and natural language processing with the latest methods in statistical data analysis, machine learning and text mining has proved to be efficient for turning unstructured textual information into meaningful knowledge. Three of the four selected papers for the section knowledge representation and management corroborate this approach and depict various experiments conducted to .extract meaningful knowledge from unstructured free texts such as extracting cancer disease characteristics from pathology reports, or extracting protein-protein interactions from biomedical papers, as well as extracting knowledge for the support of hypothesis generation in molecular biology from the Medline literature. Finally, the last paper addresses the level of formally representing and structuring information within clinical terminologies in order to render such information easily available and shareable among the health informatics community. CONCLUSIONS: Delivering common powerful tools able to automatically extract meaningful information from the huge amount of electronically unstructured free texts is an essential step towards promoting sharing and reusability across applications, domains, and institutions thus contributing to building capacities worldwide.

Knowledge representation and management: towards interoperable medical terminologies.

OBJECTIVES: To summarize current outstanding research in the field of knowledge representation and management. METHOD: Synopsis of the articles selected for the IMIA Yearbook 2009. RESULTS: Four excellent papers have been selected for the section knowledge representation and management. All these papers are concerned with terminological systems whether it is to detect equivalent concept definitions, to structure narratives, to compare existing lay and professional terms or to reformulate the SNOMED's logical formalism towards a more expressive language. CONCLUSIONS: The ability of one computer system to access and use the resources of another system becomes crucial in a world where the amount of electronically stored data increases continuously. The selected papers for the section knowledge representation and management corroborate that interoperable medical terminologies play a growing and strategic role in Electronic Health Record (EHR) systems. Indeed, they allow data in clinical systems to be defined in a more uniform and granular manner, thus leading to flexible, semantically interoperable and trust-worthy health information systems.

Decision support, knowledge representation and management: structuring knowledge for better access. Findings from the Yearbook 2008 Section on Decision Support, Knowledge Representation and Management.

OBJECTIVES: To summarize current outstanding research in the field of decision support, knowledge representation and management. METHOD: Synopsis of the articles selected for the IMIA Yearbook 2008. RESULTS: Five papers from international peer reviewed journals have been selected for the section on decision support, knowledge representation and management. They address a wide range of topics such as the recognition and extraction of negation or time from clinical narratives, the use of ontological elements to reduce the complexity of natural language processing applications or to strengthen the precision of document retrieval as well as the benefits of integrating clinical decision support within computer provider order entry. CONCLUSIONS: The best paper selection brings to light that whatever the methodological approach used in decision support, knowledge representation and management, all applications benefit from manipulating information that is expressed in both a meaningful and structured way. In order to combine the flexibility and expressive power of natural language with the computational tractability of structured data, the electronic health record based on structured narrative offers new perspectives.

Controlling the vocabulary for anatomy.

When confronted with the representation of human anatomy, natural language processing (NLP) system designers are facing an unsolved and frequent problem: the lack of a suitable global reference. The available sources in electronic format are numerous, but none fits adequately all the constraints and needs of language analysis. These sources are usually incomplete, difficult to use or tailored to specific needs. The anatomist's or ontologist's view does not necessarily match that of the linguist. The purpose of this paper is to review most recognized sources of knowledge in anatomy usable for linguistic analysis. Their potential and limits are emphasized according to this point of view. Focus is given on the role of the consensus work of the International Federation of Associations of Anatomists (IFAA) giving the Terminologia Anatomica.

Conceptual search in electronic patient record.

Search by content in a large corpus of free texts in the medical domain is, today, only partially solved. The so-called GREP approach (Get Regular Expression and Print), based on highly efficient string matching techniques, is subject to inherent limitations, especially its inability to recognize domain specific knowledge. Such methods oblige the user to formulate his or her query in a logical Boolean style; if this constraint is not fulfilled, the results are poor. The authors present an enhancement to string matching search by the addition of a light conceptual model behind the word lexicon. The new system accepts any sentence as a query and radically improves the quality of results. Efficiency regarding execution time is obtained at the expense of implementing advanced indexing algorithms in a pre-processing phase. The method is described and commented and a brief account of the results illustrates this paper.

Comparing general and medical texts for information retrieval based on natural language processing: an inquiry into lexical disambiguation.

In this paper we compare two types of corpus, focusing on the lexical ambiguity of each of them. The first corpus consists mainly of general newspaper articles and literature excerpts, while the second belongs to the medical domain. To conduct the study, we have used two different disambiguation tools. First, each tool was validated in its respective application area. We then use these systems in order to assess and compare both the general ambiguity rate and the particularities of each domain. Quantitative results show that medical documents are lexically less ambiguous than unrestricted documents. Our conclusions emphasize the importance of the application area in the design of NLP tools.

A light knowledge model for linguistic applications.

Content extraction from medical texts is achievable today by linguistic applications, in so far as sufficient domain knowledge is available. Such knowledge represents a model of the domain and is hard to collect with sufficient depth and good coverage, despite numerous attempts. To leverage this task is a priority in order to benefit from the awaited linguistic tools. The light model is designed with this goal in mind. Syntactic and lexical information are generally available with large lexicons. A domain model should add the necessary semantic information. The authors have designed a light knowledge model for the collection of semantic information on the basis of the recognized syntactical and lexical attributes. It has been tailored for the acquisition of enough semantic information in order to retrieve terms of a controlled vocabulary from free texts, as for example, to retrieve Mesh terms from patient records.

Looking back or looking all around: comparing two spell checking strategies for documents edition in an electronic patient record.

We report on the comparison of two systems for correcting spelling errors resulting in non-existent words (i.e. not listed in any lexicon). Both systems aim at improving edition of medical reports. Unlike traditional systems, based on word language models, both semantic and syntactic contexts are considered here. Both systems share the same string-to-string edit distance module, and the same contextual disambiguation principles. The differences between the two systems are located at the user interaction level: while the first system is using exclusively the left context, simulating the underlining of every mis-spelling at the end of every word typing, the second system uses the left as well as the right context and simulate a post-edition correction, when asked by the author. Our conclusion shows the improvements brought by the second approach.

Semantic handling of medical compound words through sound analysis and generation processes.

Compound words are frequently encountered in the medical domain. Their conciseness complies with the telegraphic style usually adopted by clinicians in daily practice. This amplifies the need for clarifying their semantic interpretation and representation through respectively the analysis and generation processes. While highlighting the peculiarities of medical compound words, this paper shows how model-driven linguistic tools accurately deal with the compositionality of medical language. These statements are illustrated by means of examples, stemming from the handling of surgical procedures as part of the GALEN-IN-USE project.

Medical document anonymization with a semantic lexicon.

We present an original system for locating and removing personally-identifying information in patient records. In this experiment, anonymization is seen as a particular case of knowledge extraction. We use natural language processing tools provided by the MEDTAG framework: a semantic lexicon specialized in medicine, and a toolkit for word-sense and morpho-syntactic tagging. The system finds 98-99% of all personally-identifying information.

GALEN: a third generation terminology tool to support a multipurpose national coding system for surgical procedures.

Generalised architecture for languages, encyclopedia and nomenclatures in medicine (GALEN) has developed a new generation of terminology tools based on a language independent model describing the semantics and allowing computer processing and multiple reuses as well as natural language understanding systems applications to facilitate the sharing and maintaining of consistent medical knowledge. During the European Union 4 Th. framework program project GALEN-IN-USE and later on within two contracts with the national health authorities we applied the modelling and the tools to the development of a new multipurpose coding system for surgical procedures named CCAM in a minority language country, France. On one hand, we contributed to a language independent knowledge repository and multilingual semantic dictionaries for multicultural Europe. On the other hand, we support the traditional process for creating a new coding system in medicine which is very much labour consuming by artificial intelligence tools using a medically oriented recursive ontology and natural language processing. We used an integrated software named CLAW (for classification workbench) to process French professional medical language rubrics produced by the national colleges of surgeons domain experts into intermediate dissections and to the Grail reference ontology model representation. From this language independent concept model representation, on one hand, we generate with the LNAT natural language generator controlled French natural language to support the finalization of the linguistic labels (first generation) in relation with the meanings of the conceptual system structure. On the other hand, the Claw classification manager proves to be very powerful to retrieve the initial domain experts rubrics list with different categories of concepts (second generation) within a semantic structured representation (third generation) bridge to the electronic patient record detailed terminology.

Tagging medical texts: a rule-based experiment.

In this paper we describe the construction of a part-of-speech tagger for medical document retrieval purposes, therefore we have designed a specific architecture called minimal commitment. The system uses local grammatical rules for conducting the disambiguation task. Four evaluations are conducted, with and without taking unknown words into account. In between each evaluation the modules (lexicon, guesser, rules) of the system are incrementally improved.

A toolset for medical text processing.

The processing of medical texts is a burden in the absence of a toolset designed for simple operations such as recognizing morphological variants, updating and accessing a word dictionary of the domain and segmenting words with multiple morpho-semantems. The apparent simplicity of these basic operations is an illusion because it soon becomes clear that quality implementation is a long-term task. Coherency between subtasks may be lacking unless strict rules are enforced. In fact, good tools are rarely available or have not been tailored for the medical profession. This paper aims at defining a complete toolset for medical word processing. In addition, it provides relevant examples of the inherent difficulties of this task. It reports on typical results that can be expected from an industry-standard implementation.

The power and limits of a rule-based morpho-semantic parser.

The venue of Electronic Patient Record (EPR) implies an increasing amount of medical texts readily available for processing, as soon as convenient tools are made available. The chief application is text analysis, from which one can drive other disciplines like indexing for retrieval, knowledge representation, translation and inferencing for medical intelligent systems. Prerequisites for a convenient analyzer of medical texts are: building the lexicon, developing semantic representation of the domain, having a large corpus of texts available for statistical analysis, and finally mastering robust and powerful parsing techniques in order to satisfy the constraints of the medical domain. This article aims at presenting an easy-to-use parser ready to be adapted in different settings. It describes its power together with its practical limitations as experienced by the authors.

Model-based semantic dictionaries for medical language understanding.

Semantic dictionaries are emerging as a major cornerstone towards achieving sound natural language understanding. Indeed, they constitute the main bridge between words and conceptual entities that reflect their meanings. Nowadays, more and more wide-coverage lexical dictionaries are electronically available in the public domain. However, associating a semantic content with lexical entries is not a straightforward task as it is subordinate to the existence of a fine-grained concept model of the treated domain. This paper presents the benefits and pitfalls in building and maintaining multilingual dictionaries, the semantics of which is directly established on an existing concept model. Concrete cases, handled through the GALEN-IN-USE project, illustrate the use of such semantic dictionaries for the analysis and generation of multilingual surgical procedures.

MEDTAG: tag-like semantics for medical document indexing.

Medical documentation is central in health care, as it constitutes the main means of communication between care providers. However, there is a gap to bridge between storing information and extracting the relevant underlying knowledge. We believe natural language processing (NLP) is the best solution to handle such a large amount of textual information. In this paper we describe the construction of a semantic tagset for medical document indexing purposes. Rather than attempting to produce a home-made tagset, we decided to use, as far as possible, standard medicine resources. This step has led us to choose UMLS hierarchical classes as a basis for our tagset. We also show that semantic tagging is not only providing bases for disambiguisation between senses, but is also useful in the query expansion process of the retrieval system. We finally focus on assessing the results of the semantic tagger.

Document versus data centred approach to the EPR.

This paper presents the document centred Electronic Patient Record (EPR) as currently in production in a large university hospital and subject to multiple additional developments in the coming years. A number of basic hypothesis have been developed in order to reach the best medical practice and the success of this application. In addition, the alternative approach of data centred EPR is compared, and different benefits and pitfalls are highlighted. It is not easy to evaluate the consequences of such an initial trend, but changing one's mind after having a system in daily production is anyway costly and difficult. Therefore, the selection of the right orientation in a given hospital necessitates a scientific debate.

Galen: a third generation terminology tool to support a multipurpose national coding system for surgical procedures.

GALEN has developed a new generation of terminology tools based on a language independent concept reference model using a compositional formalism allowing computer processing and multiple reuses. During the 4th framework program project Galen-In-Use we applied the modelling and the tools to the development of a new multipurpose coding system for surgical procedures (CCAM) in France. On one hand we contributed to a language independent knowledge repository for multicultural Europe. On the other hand we support the traditional process for creating a new coding system in medicine which is very much labour consuming by artificial intelligence tools using a medically oriented recursive ontology and natural language processing. We used an integrated software named CLAW to process French professional medical language rubrics produced by the national colleges of surgeons into intermediate dissections and to the Grail reference ontology model representation. From this language independent concept model representation on one hand we generate controlled French natural language to support the finalization of the linguistic labels in relation with the meanings of the conceptual system structure. On the other hand the classification manager of third generation proves to be very powerful to retrieve the initial professional rubrics with different categories of concepts within a semantic network.