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At least 19 recordsLinked to original sources
PubMed1991

Representation of clinical laboratory terminology in the Unified Medical Language System.

The Unified Medical Language System (UMLS) was examined to determine its coverage of clinical laboratory terminology in use at the Columbia-Presbyterian Medical Center (CPMC). The Metathesaurus (Meta-1) contains exact matches for 30% of 1460 CPMC laboratory terms and near matches for an additional 42%, with better coverage of atomic-level concepts ("substance" terms) than complex ones (tests and panels). The Semantic Network includes types for representing laboratory procedures (2), measured substances (at least 56) and sampled substances (at least 14), but no type to represent specimens. Few of the UMLS semantic relationships are applicable to the CPMC vocabulary. These results have implications for the utility of the UMLS for linking clinical databases to electronic medical information sources.

Clinical Laboratory Techniques↗
PubMed1998

From French vocabulary to the Unified Medical Language System: a preliminary study.

The Unified Medical Language System (UMLS) is an extensive source of biomedical knowledge developed and maintained by the U.S. National Library of Medicine (NLM). The UMLS began to include biomedical terms in other languages a few years ago. However, providing foreign terms for existing concepts is only the first step for the UMLS to become international. The current limits of the use of the UMLS in French are analyzed (partial translation, unique source of the translated concepts, improper character set, and absence of lexical resources for lexical matching tools). Some suggestions are given for French to be better integrated into the UMLS, especially for adapting the lexical resources to French. Once completed, our present work is expected to give the UMLS the capability to be effectively queried in French.

France↗
PubMed2004

The Unified Medical Language System (UMLS): integrating biomedical terminology.

The Unified Medical Language System (http://umlsks.nlm.nih.gov) is a repository of biomedical vocabularies developed by the US National Library of Medicine. The UMLS integrates over 2 million names for some 900,000 concepts from more than 60 families of biomedical vocabularies, as well as 12 million relations among these concepts. Vocabularies integrated in the UMLS Metathesaurus include the NCBI taxonomy, Gene Ontology, the Medical Subject Headings (MeSH), OMIM and the Digital Anatomist Symbolic Knowledge Base. UMLS concepts are not only inter-related, but may also be linked to external resources such as GenBank. In addition to data, the UMLS includes tools for customizing the Metathesaurus (MetamorphoSys), for generating lexical variants of concept names (lvg) and for extracting UMLS concepts from text (MetaMap). The UMLS knowledge sources are updated quarterly. All vocabularies are available at no fee for research purposes within an institution, but UMLS users are required to sign a license agreement. The UMLS knowledge sources are distributed on CD-ROM and by FTP.

Animals↗
PubMed1999

Automatic enrichment of the unified medical language system starting from the ADM knowledge base.

The Unified Medical Language System (UMLS) project aims to provide a repository of terms, concepts and relationships from several medical classifications. This work describes the possibility to enrich automatically with meaningful links the UMLS database by using description of diseases from another knowledge base, in our case ADM (Aide au Diagnostic Medical). In spite of the constraints and the difficulties to qualify the interconcept links, the results show that it is possible to find and create new links from a french knowledge database to the UMLS one. One of the interests of this work is that the automated learning of the connections could be used with others knowledge databases like expert system databases.

Algorithms↗
PubMed2002

Dental concepts in the Unified Medical Language System.

OBJECTIVE: Currently, no comprehensive, controlled vocabulary for dentistry is available. The objective of this study was to determine how well the Unified Medical Language System, the largest repository of concepts and terms in biomedicine, represents dental concepts. METHOD AND MATERIALS: The dental subset of concepts was extracted from Unified Medical Language System using the software program APEX (APplication for the EXtraction of domain-specific concepts). The relationships contained in the Unified Medical Language System Metathesaurus were used to locate the concepts related to 12 seed terms. The Encyclopédie Médico-Chirurgicale (513 dental terms) and the Diagnostic Codes developed by Leake et al (124 terms) were compared to the dental subset. Terms were classified as exact match, related term, or no match. The resultant matching characteristics were compared to those determined by the National Library of Medicine/Agency for Health Care Policy and Research Large Scale Vocabulary Test. RESULTS: The dental subset of Unified Medical Language System contained 948 concepts. The Encyclopédie Médico-Chirurgicale and the Diagnostic Codes exhibited similar matching characteristics for exact match (61.6% and 58.9%, respectively) and related term (38.0% and 32.2%, respectively). For no match, the matching frequencies were significantly different (P < .001). CONCLUSION: The Unified Medical Language System may be a comprehensive source of terms suitable for various representation requirements in dentistry.

Chi-Square Distribution↗
PubMed2004

An enriched unified medical language system semantic network with a multiple subsumption hierarchy.

OBJECTIVE: The Unified Medical Language System's (UMLS's) Semantic Network's (SN's) two-tree structure is restrictive because it does not allow a semantic type to be a specialization of several other semantic types. In this article, the SN is expanded into a multiple subsumption structure with a directed acyclic graph (DAG) IS-A hierarchy, allowing a semantic type to have multiple parents. New viable IS-A links are added as warranted. DESIGN: Two methodologies are presented to identify and add new viable IS-A links. The first methodology is based on imposing the characteristic of connectivity on a previously presented partition of the SN. Four transformations are provided to find viable IS-A links in the process of converting the partition's disconnected groups into connected ones. The second methodology identifies new IS-A links through a string matching process involving names and definitions of various semantic types in the SN. A domain expert is needed to review all the results to determine the validity of the new IS-A links. RESULTS: Nineteen new IS-A links are added to the SN, and four new semantic types are also created to support the multiple subsumption framework. The resulting network, called the Enriched Semantic Network (ESN), exhibits a DAG-structured hierarchy. A partition of the ESN containing 19 connected groups is also derived. CONCLUSION: The ESN is an expanded abstraction of the UMLS compared with the original SN. Its multiple subsumption hierarchy can accommodate semantic types with multiple parents. Its representation thus provides direct access to a broader range of subsumption knowledge.

Algorithms↗
PubMed1996

Mapping medical vocabularies to the Unified Medical Language System.

This paper presents our work in automated mapping of medical vocabularies to the National Library of Medicine's Unified Medical Language System (UMLS). We used the UMLS Knowledge Source (KS) tool to map terms from several sources to UMLS Metathesaurus concepts. We compared performance of the KS tools with our own Minimal Representable Units Method (MRUM). The KS tools were able to map terms from 13% to 54% of the time, depending on the term set and the KS options used. Our MRUM method mapped between 96% and 99% of the terms. Based on our experience, we believe that questions remain about the best method by which the UMLS can be used to achieve automated term translation.

Algorithms↗
PubMedDate not supplied

UMLS-based access to CPR data. Unified Medical Language Systems.

This paper describes the results of a project that explores the use the Unified Medical Language System (UMLS) for knowledge-driven tasks, such as browsing a computer-based patient record (CPR). The project consisted of a number of steps: the mapping between CPR terms and UMLS concepts, the development of an algorithm that explores the CPR data using this mapping and the implementation of a first prototype browser that visualizes 'found' data. A second task addressed in this project has been the direct access to online medical literature (MEDLINE) using the UMLS concepts found in the CPR data. In this project, we used a preliminary version of the Open Records for Patient Care (ORCA) CPR that consisted only of the history and physical examination data of patient suffering from heart failure.

Algorithms↗
PubMedDate not supplied

Auditing the Unified Medical Language System with semantic methods.

OBJECTIVE: The National Library of Medicine's (NLM) Unified Medical Language System (UMLS) includes a Metathesaurus (Meta), which is a compilation of medical terms drawn from over 30 controlled vocabularies, and a Semantic Net, which contains the semantic types used to categorize Meta concepts and the semantic relations to connect them. Meta has been constructed through lexical matching techniques and human review. The purpose of this study was to audit the Meta using semantic techniques to identify possible inconsistencies. METHODS: Five different techniques were applied: (1) detection of ambiguity in Meta concepts with two or more semantic types, (2) detection of interchangeable keyword synonyms, (3) detection of redundant pairs of Meta concepts (using lexical matching combined with keyword synonyms), (4) detection of inconsistent parent-child relationships in Meta (based on the semantic type information), and (5) discovery of pairs of semantic types for which relations could be added to the Semantic Net, based on "other" relationships between Meta concepts. RESULTS: Of 57,592 concepts with multiple semantic types, 1817 (3.2%) were judged to be ambiguous. Keyword analysis showed 7121 pairs of interchangeable words. Using the keyword pairs, 5031 pairs of potentially redundant concepts were suggested, of which 3274 (65.1%) were judged to actually be redundant. Review of the 100,586 parent-child relationships revealed 544 (0.54%) that were incorrect. Review of the 219,664 "Other" relationships suggested 1299 places in the Semantic Net where relations between pairs of semantic types could be added. CONCLUSION: Semantic techniques, alone or in combination, can be used to audit the UMLS to detect inconsistencies that are not detectable through lexical techniques alone. Use of these methods to augment the UMLS maintenance process will lead to improvement in the UMLS.

Algorithms↗
PubMedDate not supplied

The Unified Medical Language System: toward a collaborative approach for solving terminologic problems.

The approach taken by the Unified Medical Language System (UMLS), in which disparate terminology systems are integrated, has allowed construction of an electronic thesaurus (the Metathesaurus) that avoids imposing any restrictions upon the content, structure, or semantics of the source terminologies. As such, the UMLS has served as a unifying paradigm by providing appropriate links among equivalent entities that are used in different contexts or for different purposes. It accordingly provides a vehicle through which possibly orthogonal semantic models can co-exist within a single framework. This framework provides a model for the collaborative evolution of biomedical terminology and allows a synergistic relationship between the UMLS and its source terminology systems.

Systems Integration↗
PubMed1995

Use of the Unified Medical Language System in patient care at the Columbia-Presbyterian Medical Center.

The Unified Medical Language System (UMLS) project at the United States National Library of Medicine contains and organizes a large number of terms from controlled medical vocabularies. This study examines the suitability of the UMLS for representing patient care information as it exists in the Columbia-Presbyterian Medical Center (CPMC) clinical information system. Comparisons were made between the semantic types, semantic relations and medical concepts of the UMLS and the data model entities, semantic classes, semantic relations and concepts in the CPMC system. Results of the comparison demonstrate that the UMLS structural model is appropriate for representing CPMC vocabularies and patient data and that the UMLS concepts provide excellent coverage of CPMC concepts in many areas. Recommendations are made for enhancing UMLS structure to provide additional coverage of the CPMC model. It is concluded that content expansion to provide better coverage of clinical terminology is possible within the current UMLS model.

Academic Medical Centers↗
PubMed1997

The rubber meets the road: integrating the Unified Medical Language System Knowledge Source Server into the computer-based patient record.

Ongoing improvements in the content of the Unified Medical Language System, coupled with the recent release of the Internet-based Knowledge Source Server (KSS), have prompted us to develop an interface between the KSS and our computer-based patient record. We confronted many challenges while developing a robust interface to an Internet-based server, and in integrating the process of codification into the workflow of clinicians. An initial evaluation of the interface in the clinical environment suggests that acceptable performance is attainable. The benefits of using an Internet-accessible tool in a clinical information system appear to justify the effort required.

Humans↗
PubMed1994

Acceptability of Unified Medical Language System terms as substitute for natural language general medicine clinic diagnoses.

The acceptability of using the Unified Medical Language System (UMLS) concept phrases to substitute for physicians' diagnosis statements was investigated. Physician diagnosis statements recorded in the University of New Mexico's General Medicine Clinic were input into a computer program that automatically finds the best matching UMLS concept phrases. The computer program written in C++ integrates UMLS searching and browsing with a graphical user interface. Five attending physicians in the Department of Internal Medicine rated the acceptability of the UMLS concept phrase as a substitute for the original physician statement. One hundred and ninety-five patients' notes were examined with 447 diagnosis statements recorded of which 271 statements were unique. Attending physicians rated their satisfaction with the automated UMLS substitutes on a scale of 1 (extremely dissatisfied) to 5 (extremely satisfied). Intrarater (mean 0.94) and interrater correlations (mean 0.75) were high. The mean rating was 4.0 (quite satisfied). Most (73%) of the substitution were satisfactory (rating of 4 or 5), 16% were neutral (rating of 3), and 21% were unsatisfactory (rating of 1 or 2). A review of the substitutions showed a frequent lack of clinical modifier terms in UMLS as has been previously described. Comparison to a previous study shows the broader term coverage of UMLS to be a more acceptable source of diagnosis codes than using International Classification of Diseases revision 9 alone. These results suggest that UMLS can be an effective tool for coding unconstrained physician diagnoses.

Consumer Behavior↗
PubMedDate not supplied

The Unified Medical Language System: an informatics research collaboration.

In 1986, the National Library of Medicine (NLM) assembled a large multidisciplinary, multisite team to work on the Unified Medical Language System (UMLS), a collaborative research project aimed at reducing fundamental barriers to the application of computers to medicine. Beyond its tangible products, the UMLS Knowledge Sources, and its influence on the field of informatics, the UMLS project is an interesting case study in collaborative research and development. It illustrates the strengths and challenges of substantive collaboration among widely distributed research groups. Over the past decade, advances in computing and communications have minimized the technical difficulties associated with UMLS collaboration and also facilitated the development, dissemination, and use of the UMLS Knowledge Sources. The spread of the World Wide Web has increased the visibility of the information access problems caused by multiple vocabularies and many information sources which are the focus of UMLS work. The time is propitious for building on UMLS accomplishments and making more progress on the informatics research issues first highlighted by the UMLS project more than 10 years ago.

Computer Communication Networks↗
PubMed2000

Knowledge acquisition to qualify Unified Medical Language System interconceptual relationships.

Adding automatically relations between concepts from a database to a knowledge base such as the Unified Medical Language System can be very useful to increase the consistency of the latter one. But the transfer of qualified relationships is more interesting. The most important interest of these new acquisitions is that the UMLS became more compliant and medically pertinent to be used in different medical applications. This paper describes the possibility to inherit automatically medical inter-conceptual relationships qualifiers from a disease description included into a database and to integrate them into the UMLS knowledge base. The paper focuses on the transmission of knowledge from a French medical database to an English one.

Artificial Intelligence↗
PubMedDate not supplied

Evaluation of the Unified Medical Language System as a medical knowledge source.

OBJECTIVE: The authors evaluated the use of the Unified Medical Language System (UMLS) as a medical knowledge source for the representation of medical procedures in the MAOUSSC system. DESIGN: MAOUSSC, a multiaxial coding system, was used for the representation of 1500 procedures from 15 clinical specialties, using UMLS concepts (augmented by full sources for three new vocabularies being added to the UMLS) and relationships whenever possible. Evaluation criteria for the UMLS included (1) completeness of representation of concepts and of inter-concept relationships, (2) consistency in the categorization of both concepts and inter-concept relationships, and (3) usability, including adaptability of the UMLS to a foreign language (French), its suitability to a geographic region with different medical practices than the USA, and issues relative to the annual update changes in the test vocabularies. RESULTS: During the MAOUSSC trial, the number of missing concepts or relationships identified in the augmented UMLS sources was deemed to be inconsequential relative to overall project goals. "Missing" UMLS inter-concept relationships were identified, although they were small in number. Some inconsistencies in the UMLS were noted, especially in the area of hierarchic relationships. CONCLUSION: After UMLS was used for five years as a knowledge source for representing 1500 complex medical procedures in MAOUSSC, its value is considered significant. Future editions of the UMLS are expected to improve representation of inter-concept relationships and global consistency.

Language↗