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Biomedical subjects

L M Fagan

Publications and source records attributed to L M Fagan.

43 records · Page 3Linked to original sources
PubMed1976

Computerized consultation system for selection of antimicrobial therapy.

Mycin, a computer-based consultation system which provides to physicians antimicrobial therapy recommendations for patients with bacterial infections, is described. The consultation program arrives at therapeutic decisions using a built-in knowledge base as well as patient data entered by the physician. The system is capable of explaining its recommendations and answering questions about its reasoning process. The system's knowledge can be updated and corrected easily by infectious disease experts. At present the system is operational within a research setting; its routine use in a clinical setting will require further evaluation of its reliability and effectiveness.

Anti-Infective Agents↗
PubMedDate not supplied

A continuous-speech interface to a decision support system: I. Techniques to accommodate for misrecognized input.

OBJECTIVE: Develop a continuous-speech interface that allows flexible input of clinical findings into a medical diagnostic application. DESIGN: The authors' program allows users to enter clinical findings using their own vernacular. It displays from the diagnostic program's controlled vocabulary a list of terms that most closely matches the input, and allows the user to select the single best term. The interface program includes two components: a speech-recognition component that converts utterances into text strings, and a language-processing component that matches recognized text strings with controlled-vocabulary terms. The speech-recognition component is composed of commercially available speech-recognition hardware and software, and developer-created grammars, which specify the language to be recognized. The language-processing component is composed of a translator, which extracts a canonical form from both recognized text strings and controlled-vocabulary terms, and a matcher, which measures the similarity between the two canonical forms. RESULTS: The authors discovered that grammars constructed by a physician, who could anticipate how users might speak findings, supported speech recognition better than did grammars constructed programmatically from the controlled vocabulary. However, this programmatic method of grammar construction was more time efficient and better supported long-term maintenance of the grammars. The authors also found that language-processing techniques recovered some of the information lost due to speech misrecognition, but were dependent on the completeness of supporting synonym dictionaries. CONCLUSIONS: The authors' program demonstrated the feasibility of using continuous speech to enter findings into a medical application. However, improvements in speech-recognition technology and language-processing techniques are needed before natural continuous speech becomes an acceptable input modality for clinical applications.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

A continuous-speech interface to a decision support system: II. An evaluation using a Wizard-of-Oz experimental paradigm.

OBJECTIVE: Evaluate the performance of a continuous-speech interface to a decision support system. DESIGN: The authors performed a prospective evaluation of a speech interface that matches unconstrained utterances of physicians with controlled-vocabulary terms from Quick Medical Reference (QMR). The performance of the speech interface was assessed in two stages: in the real-time experiment, physician subjects viewed audiovisual stimuli intended to evoke clinical findings, spoke a description of each finding into the speech interface, and then chose from a list generated by the interface the QMR term that most closely matched the finding. Subjects believed that the speech recognizer decoded their utterances; in reality, a hidden experimenter typed utterances into the interface (Wizard-of-Oz experimental design). Later, the authors replayed the same utterances through the speech recognizer and measured how accurately utterances matched with appropriate QMR terms using the results of the real-time experiment as the "gold standard." MEASUREMENTS: The authors measured how accurately the speech-recognition system converted input utterances to text strings (recognition accuracy) and how accurately the speech interface matched input utterances to appropriate QMR terms (semantic accuracy). RESULTS: Overall recognition accuracy was less than 50%. However, using language-processing techniques that match keywords in recognized utterances to keywords in QMR terms, the semantic accuracy of the system was 81%. CONCLUSIONS: Reasonable semantic accuracy was attained when language-processing techniques were used to accommodate for speech misrecognition. In addition, the Wizard-of-Oz experimental design offered many advantages for this evaluation. The authors believe that this technique may be useful to future evaluators of speech-input systems.

Adolescent↗
PubMedDate not supplied

The PEN-Ivory project: exploring user-interface design for the selection of items from large controlled vocabularies of medicine.

OBJECTIVE: To explore different user-interface designs for structured progress note entry, with a long-term goal of developing design guidelines for user interfaces where users select items from large medical vocabularies. DESIGN: The authors created eight different prototypes of a pen-based progress-note-writing system called PEN-Ivory. Each prototype allows physicians to write patient progress notes using simple pen-based gestures such as circle, line-out, and scratch-out. The result of an interaction with PEN-Ivory is a progress note in English prose. The eight prototypes were designed in a principled way, so that they differ from one another in just one of three different user-interface characteristics. MEASUREMENTS: Five of the eight prototypes were tested by measuring the time it took 15 users, each using a distinct prototype, to document three patient cases consisting of a total of 63 medical findings. RESULTS: The prototype that allowed the fastest data entry had the following three user-interface characteristics: it used a paging rather than a scrolling form, it used a fixed palette of modifiers rather than a dynamic "pop-up" palette, and it made available all findings from the controlled vocabulary at once rather than displaying only a subset of findings generated by analyzing the patient's problem list. CONCLUSION: Even simple design changes to a user interface can make dramatic differences in user performance. The authors discuss possible influences on performance, such as positional constancy, user uncertainty and system anticipation, that may contribute significantly to the effectiveness of systems that display menus of items from large controlled vocabularies of medicine.

Medical Records↗
PubMedDate not supplied

A methodology for generating computer-based explanations of decision-theoretic advice.

Decision analysis is an appealing methodology with which to provide decision support to the practicing physician. However, its use in the clinical setting is impeded because computer-based explanations of decision-theoretic advice are difficult to generate without resorting to mathematical arguments. Nevertheless, human decision analysts generate useful and intuitive explanations based on decision trees. To facilitate the use of decision theory in a computer-based decision support system, the authors developed a computer program that uses symbolic reasoning techniques to generate nonquantitative explanations of the results of decision analyses. A combined approach has been implemented to explain the differences in expected utility among branches of a decision tree. First, the mathematical relationships inherent in the structure of the tree are used to find any asymmetries in tree structure or inequalities among analogous decision variables that are responsible for a difference in expected utility. Next, an explanation technique is selected and applied to the most significant variables, creating a symbolic expression that justifies the decision. Finally, the symbolic expression is converted to English-language text, thereby generating an explanation that justifies the desirability of the choice with the greater expected utility. The explanation does not refer to mathematical formulas, nor does it include probability or utility values. The results suggest that explanations produced by a combination of decision analysis and symbolic processing techniques may be more persuasive and acceptable to clinicians than those produced by either technique alone.

Artificial Intelligence↗
PubMedDate not supplied

Managing the data from respiratory measurements.

Clinical decisionmaking depends upon properly interpreting the significance of physiological and other clinical data. Our experience, summarized in six case studies, suggests that no one variable is sufficient for making clinical decisions. Rather, different parameters are relevant in different situations. This article summarizes two techniques for improving the effectiveness of clinical decisionmaking in the ICU using quantitative physiological monitoring data. First, mathematical modeling has been used for measuring the volume of gas in the lungs of patients receiving mechanical ventilation. The technique analyzes the transient response to oxygen change; thus it is suitable for routine use in the ICU. Second, symbolic processing has been used for interpreting the clinical significance of measured data. This symbolic processing is used for recognizing artifact in measured data, determining expected physiological meaning of measured data in different clinical situations, identifying physiological status, and identifying therapy that may be appropriate for meeting therapeutic goals or correcting physiological problems in patients in the intensive care unit.

Aged↗