Desiderata for controlled medical vocabularies in the twenty-first century

Builders of medical informatics applications need controlled medical vocabularies to support their applications and it is to their advantage to use available standards. In order to do so, however, these standards need to address the requirements of their intended users. Over the past decade, medical informatics researchers have begun to articulate some of these requirements. This paper brings together some of the common themes which have been described, including: vocabulary content, concept orientation, concept permanence, nonsemantic concept identifiers, polyhierarchy, formal definitions, rejection of "not elsewhere classified" terms, multiple granularities, multiple consistent views, context representation, graceful evolution, and recognized redundancy. Standards developers are beginning to recognize and address these desiderata and adapt their offerings to meet them.     

Expertise in expert systems: knowledge acquisition for biological expert systems

A method of constant stimuli (MCS) for measuring heartbeat detection was examined by comparing performance on this method with the Brener and Kluvitse (BK) method and a variant of the Whitehead (WH') method. All methods required subjects to judge the simultaneity of heartbeat sensations and tones, and each yielded measures of judgment precision and of the temporal location of heartbeat sensations relative to the electrocardiogram R-wave. Both measures were found to be significantly correlated across tasks. A greater proportion of subjects met criteria for classification as heartbeat detectors on the MCS (54%) and BK (50%) tasks than on the WH' task (33%). In the MCS and BK tasks, subjects judged tones presented 100-300 ms after the R-wave to be most simultaneous with heartbeat sensations. Intratask correlations showed that only the MCS procedure yielded stable measurements of both judgment precision and temporal location. The MCS procedure possesses commendable psychometric properties and provides a simpler means than the BK procedure of examining heartbeat detection.     

Medical expert assessment in civil and criminal law--stand for evaluating medical expert assessment

The standard for the assessment of the medical expert opinion is defined by the high demands expected from the judgement of a high court: Objectiveness, solid knowledge, self-criticism, in contestability in diction and firmness in the argumentation. From the legal point of view, the knowledge of the medical expert witness has to clearly go beyond the knowledge of his profession. The obligation for objectiveness is the basis of expert witness' activity. From the medical point of view, the physician has to take into account during the preparation of his expert assessment that structural deficiency of the personnel and surgical equipment of a department for surgery frequently plays a role due to the development of surgery to high tech medicine and the hospital physician cannot affect this. It is necessary for a physician as an expert witness to have basic knowledge about the evidence law and the medical liability process. On the other hand, judges and lawyers should basically know the medical way of thinking.     

Medical expert systems]

Expert systems are software systems that can successfully compare to human experts. Their purpose is mostly advisory. Besides, they give explanation and advice to human experts when performing certain tasks. They are intelligent information systems, and are capable to explain and justify their conclusions. Knowledge systems are smaller software systems, and are usually less successful than human experts. Main reasons for expert systems development in medicine are: need for justification of decisions, need for enhancing performances in many uncertain relations; need for explaining of decision making process etc. One of the reasons of developing knowledge-based systems was that conventional statistic formalisms have not provided satisfactory solutions in medical decision making (MDM). Also, today, the relations between cases and conclusions are not universally valid. So, few causes can provide the same conclusion. Besides, data are not necessarily absolutely accurate. The area of applying expert systems is very wide: diagnosis, prognosis, self-education, directing etc. Basic structure of expert system consists of: knowledge, data base, inferring mechanism, explaining mechanism and user-interface. Though, expert systems also have certain bad features: primarily, they are not physicians i.e. they can not examine a patient. Furthermore, expert system that is good for one certain area is often not good for another one. There are some cases, when these systems can confuse a physician and make him to make a wrong decision. This occurs very often in two specific cases: when the clinical situation is urgent; and when accuracy of clinical information is not definite.     

MEDUSA: a fuzzy expert system for medical diagnosis of acute abdominal pain

Even today, the diagnosis of acute abdominal pain represents a serious clinical problem. The medical knowledge in this field is characterized by uncertainty, imprecision and vagueness. This situation lends itself especially to be solved by the application of fuzzy logic. A fuzzy logic-based expert system for diagnostic decision support is presented (MEDUSA). The representation and application of uncertain and imprecise knowledge is realized by fuzzy sets and fuzzy relations. The hybrid concept of the system enables the integration of rule-based, heuristic and case-based reasoning on the basis of imprecise information. The central idea of the integration is to use case-based reasoning for the management of special cases, and rule-based reasoning for the representation of normal cases. The heuristic principle is ideally suited for making uncertain, hypothetical inferences on the basis of fuzzy data and fuzzy relations.     

Clinical problem solving--the role of expert laboratory systems

The contrasting findings obtained in the studies that have attempted to correlate the stage of endometriosis with severity of pain symptoms suggest that some specific characteristics of the lesions are more implicated in the genesis of pain than disease extension per se. Thus, fresh, metabolically active, intraperitoneal implants may cause functional pain symptoms such as dysmenorrhea, whereas infiltrating, nodular and fibrotic lesions are responsible for organic-type pain such as deep dyspareunia. Women with symptomatic endometriosis seem to have reduced peripheral beta-endorphin production in comparison with pain patients without the disease, although neuroendocrine modulation of pelvic nociceptive stimuli is far from clear. There is little evidence to support the notion that specific psychiatric features render some women more vulnerable to developing endometriosis, as results from investigations performed on women with asymptomatic lesions are very similar to normative data. Moreover, it appears that the psychological profile of symptomatic patients with the disease is no different from those with pain and a normal pelvis or other gynecological conditions. Consequently, the local biochemical and physical effects of lesions seem to be the most important factors in determining frequency and severity of symptoms.     

Health-care technology transfer: expert and information systems for developing countries

The alkaline phosphatase immunoassay (APIA) is an antibody detection technique which permits the diagnosis of schistosomiasis using a butanolic extract preparation from adult worms. APIA has demonstrated high sensitivity and specificity in previous reports with well characterized human sera. Its potential as a diagnostic tool for epidemiological surveillance was assessed in comparison with three other diagnostic tests: stool examination, ELISA with soluble egg antigen (SEA) and the circumoval precipitin test (COPT). APIA was 100% specific in an area without Schistosoma mansoni transmission and had 89% sensitivity in an endemic area where 69% of the infected subjects excreted less than 100 eggs g of faeces. It was found to be less sensitive in children under 5 years of age who were positive by the COPT test. APIA can be applied as an initial screening test, based on its high sensitivity, specificity, absence of cross-reactivity with intestinal parasites and the fact that it is a technique suitable for use in epidemiological surveillance.     

A medical expert system approach using artificial neural networks for standardized treatment planning

PURPOSE: Many radiotherapy treatment plans involve some level of standardization (e.g., in terms of beam ballistics, collimator settings, and wedge angles), which is determined primarily by tumor site and stage. If patient-to-patient variations in the size and shape of relevant anatomical structures for a given treatment site are adequately sampled, then it would seem possible to develop a general method for automatically mapping individual patient anatomy to a corresponding set of treatment variables. A medical expert system approach to standardized treatment planning was developed that should lead to improved planning efficiency and consistency. METHODS AND MATERIALS: The expert system was designed to specify treatment variables for new patients based upon a set of templates (a database of treatment plans for previous patients) and a similarity metric for determining the goodness of fit between the relevant anatomy of new patients and patients in the database. A set of artificial neural networks was used to optimize the treatment variables to the individual patient. A simplified example, a four-field box technique for prostate treatments based upon a single external contour, was used to test the viability of the approach. RESULTS: For a group of new prostate patients, treatment variables specified by the expert system were compared to treatment variables chosen by the dosimetrists. Performance criteria included dose uniformity within the target region and dose to surrounding critical organs. For this standardized prostate technique, a database consisting of approximately 75 patient records was required for the expert system performance to approach that of the dosimetrists. CONCLUSIONS: An expert system approach to standardized treatment planning has the potential of improving the overall efficiency of the planning process by reducing the number of iterations required to generate an optimized dose distribution, and to function most effectively, should be closely integrated with a dosimetric based treatment planning system.     

Current aspects of creation of expert systems in aviation medicine

Topical directions of developing the medical expert systems (MES) are considered. The problems to be solved by using programming and informational means as part of MES are discussed. A classification of the knowledge of expert physicians who directly deal with decision making is proposed. The characteristics of the developed MES well appreciated by the results of their operation are given. They show new trends associated with the update of medical knowledge and the developmental level of information technologies.     

Volumetric flow rate comparisons for water and product on pasteurization systems

A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.     

Techniques in evaluating nursing expert systems: A case study

Discusses the problems related to the theoretical validation of selecting a method of investigation, its application with due consideration for the algorithm of osteological identification, and assessment of the results of this or that method from the viewpoint of the objectiveness and informative value of the method for osteological identification.     

Recall by expert medical practitioners and novices as a record of processing attention.

Using recall of clinical protocols as a measure of expertise in medicine has yielded disappointingly small effects. Experiments using recall of clinical laboratory data are presented to provide an explanation. In one experiment, subjects either deliberately memorized or first diagnosed and then were incidentally asked for memory. With incidental instructions, experts recalled over twice as much data as did students, but with memorization instructions, student performance approximated that of experts. Experts also showed a large advantage over students in incidental recall of data that were not relevant to the problem solution. These results suggest that expert processing in this "discrete, independent inputs" domain requires effortful analysis with minimal reliance on default values, rather than relatively effortless pattern perception reported in highly visual areas of expertise. For this area, intentional memory is a misleading measure of expertise. However, incidental memory is a valuable measure of processing during diagnosis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recent developments of collagen-based materials for medical applications and drug delivery systems

In this review, an attempt was made to summarize some of the recent developments in the application of collagen as a biomaterial and in drug delivery systems. The main applications covered include: collagen for burn/wound cover dressings; osteogenic and bone filling materials; antithrombogenic surfaces; and immobilization of therapeutic enzymes. Recently, collagen used as a carrier for drug delivery has attracted many researchers throughout the world. The use of collagen for various drug delivery systems has also been reviewed in this article. Collagen-based drug delivery systems include: injectable microspheres based on gelatin (degraded form of collagen); implantable collagen-synthetic polymer hydrogels; interpenetrating networks of collagen; and synthetic polymers collagen membranes for ophthalmic delivery. Recent efforts to use collagen-liposomal composites for controlled drug delivery, as well as collagen as controlling membranes for transdermal delivery, were also reviewed. In this review, the main emphasis was on the work done in our laboratory.     

A systems analysis approach to medical error

Using decerebrate frogs (Rana catesbeiana), we investigated the role of vagal and laryngeal sensory feedback in controlling motor activation of the larynx. Vagal and laryngeal nerve afferents were activated by electrical stimulation of the intact vagal and laryngeal nerves. Pulmonary afferents were activated by lung inflation. Reflex responses were recorded by measuring efferent activity in the laryngeal branch of the vagus (Xl) and changes in glottal aperture. Two glottic closure reflexes were identified, one evoked by lung inflation or electrical stimulation of the main branch of the vagus (Xm), and the other by electrical stimulation of Xl. Lung inflation evoked a decrementing burst of Xl efferent activity and electrical stimulation of Xm resulted in a brief burst of Xl action potentials. Electrical stimulation of Xl evoked a triphasic mechanical response, an abrupt glottal constriction followed by glottal dilatation followed by a long-lasting glottal constriction. The first phase was inferred to be a direct (nonreflex) response to the stimulus, whereas the second and third represent reflex responses to the activation of laryngeal afferents. Intracellular recordings of membrane potential of vagal motoneurons of lung and nonlung types revealed EPSPs in both types of neurons evoked by stimulation of Xm or Xl, indicating activation of glottal dilator and constrictor motoneurons. In summary, we have identified two novel reflexes producing glottic closure, one stimulated by activation of pulmonary receptors and the other by laryngeal receptors. The former may be part of an inspiratory terminating reflex and the latter may represent an airway protective reflex.