Medical informatics and problem-based learning

Problem-based learning (PBL) is an educational method that can be considered as an alternative to the traditional, discipline-based, approach to teaching. In this paper the characteristics of both approaches are discussed and compared. Some background knowledge concerning the principles that determine the success of instructional methods is presented. Finally, it is discussed how medical informatics can be taught in a PBL environment.

Do short cases elicit different thinking processes than factual knowledge questions do?

PURPOSE

To assess whether case-based questions elicit different thinking processes from factual knowledge-based questions.

METHOD

20 general practitioners (GPs) and 20 students solved case-based questions and matched factual knowledge-based questions while thinking aloud. Verbatim protocols were analysed. Five indicators were defined: extent of protocols; immediate responses; re-reading of information given in the stem or case after the question had been read; order of re-reading information, and type of consideration, i.e. 'true-false' type or 'vector', that is, a deliberation which has a magnitude and a direction.

RESULTS

Cases elicited longer protocols than factual knowledge questions. Students re-read more given information than GPs. GPs gave an immediate response on twice as many occasions as students. GPs re-ordered the case information, whereas students re-read the information in the order it was presented. This ordering difference was not found in the factual knowledge questions. Factual knowledge questions mainly led to 'true-false' considerations, whereas cases elicited mainly 'vector' considerations.

CONCLUSION

Short case-based questions lead to thinking processes which represent problem-solving ability better than those elicited by factual knowledge questions.

Knowledge Encapsulation and the Intermediate Effect

The present study explored the role of so-called encapsulated knowledge in diagnosing clinical cases outside the expert physicians' domain of expertise. Neurologists and 2nd-year and 6th-year medical students were required to diagnose, recall, and explain the signs and symptoms of two cardiological and two pulmonological clinical case descriptions. Our experiment showed that neurologists diagnosed these clinical cases faster and more accurately than 2nd-year and 6th-year medical students. An inverted U-shaped relationship with levels of expertise was found in recall and pathophysiological protocols: 6th-year medical students remembered more information from the cases and produced more elaborated explanations for the described signs and symptoms than both other groups. The proportion of encapsulating concepts in recall and pathophysiological explanations, on the other hand, increased with levels of expertise. This pattern is similar to that found in previous studies on clinical case representations using only cases within the expert physicians' domain of expertise. Therefore, these results suggest that expert physicians process clinical case descriptions both within and outside their domain of expertise in essentially the same way. Copyright 2000 Academic Press.

Scripts and medical diagnostic knowledge: theory and applications for clinical reasoning instruction and research

Medical diagnosis is a categorization task that allows physicians to make predictions about features of clinical situations and to determine appropriate course of action. The script concept, which first arose in cognitive psychology, provides a theoretical framework to explain how medical diagnostic knowledge can be structured for diagnostic problem solving. The main characteristics of the script concept are pre-stored knowledge, values acceptable or not acceptable for each illness attribute, and default values. Scripts are networks of knowledge adapted to goals of clinical tasks. The authors describe how scripts are used in diagnostic tasks, how the script concept fits within the clinical reasoning literature, how it contrasts with competing theories of clinical reasoning, how educators can help students build and refine scripts, and how scripts can be used to assess clinical competence.

A failure to reproduce the intermediate effect in clinical case recall

PURPOSE

To investigate the differences between experts, intermediates, and novices in diagnosing and representing clinical cases under various time constraints.

METHOD

Second-, fourth-, and sixth-year medical students, and internists studied, diagnosed, and recalled four clinical cases from internal medicine. Participants were allowed to study each case for either 3 minutes, 1 minute 15 seconds, or 30 seconds. The study replicated in most ways the 1993 clinical case recall study of Schmidt and Boshuizen.

RESULTS

As expected, diagnostic accuracy increased with level of expertise. However, this study failed to disclose the intermediate effect in clinical case recall that was found in the original study. Instead, a positive linear relation between expertise level and case recall was found. The discrepancy resulted from more elaborate recall by experts in the present study. Constraining processing time did not effect diagnostic accuracy, but equally affected the recall performances of the participants of all expertise levels. This contrasts with the earlier finding that experts' recall is independent of processing time.

CONCLUSION

Although it is unclear why the experts' case processing was more elaborate in the present study than in the earlier study, it must be concluded that expert medical knowledge is so flexibly organized that experts can easily represent clinical cases in either the encapsulated or the elaborated mode.

Measuring knowledge and clinical reasoning skills in a problem-based curriculum

The purpose of this study was to investigate the validity of the Progress Test that was specially designed for measuring the growth of knowledge and clinical reasoning skills in a problem-based medical curriculum. Scores and subscores of students from the different categories of the Progress Test were compared with their scores on a Clinical Reasoning Tests. Both the Progress Test and the Clinical Reasoning Test revealed the same pattern of increasing scores over the years, and had a high intercorrelation. Further analyses revealed that the clinical sciences subscore in the progress test explained the variations in the clinical reasoning test scores. The knowledge of the behavioural sciences subscore made a small but independent contribution. The knowledge of the biomedical sciences subscore did not have this independent effect. These outcomes are discussed in this paper from the perspective of development of medical expertise research and theory. Some educational consequences are also discussed.

The development of diagnostic competence: comparison of a problem-based, an integrated, and a conventional medical curriculum

PURPOSE

To compare the diagnostic performances of students in five curriculum years educated at schools with problem-based, integrative, or conventional medical curricula.

METHOD

Data were analyzed in 1994 for 612 students in their second, third, or fourth (preclinical) or fifth or sixth (clinical) years at three Dutch medical schools with problem-based, integrative, or conventional curricula. The students gave differential diagnoses for 30 case histories that were epidemiologically representative of Dutch society and covered all organ systems. The numbers of accurate diagnostic hypotheses were tallied for each of the groups involved. The data were analyzed using analysis of variance and post-hoc Newman-Keuls tests.

RESULTS

Overall, the students trained within the problem-based framework and the students trained within the integrated curriculum made more accurate diagnoses than the students trained within the conventional curriculum. No overall differences were found between the students in the problem-based and integrated curricula, although the second- and third-year students from the latter performed better than the second- and third-year students from both other schools.

CONCLUSION

Integration between basic and clinical sciences and an emphasis on patient problems may be the critical factors that determine superior diagnostic performance rather than whether a curriculum is self- or teacher-directed. Problem-based learning seems to live up to its expectations, but so does the integrated approach to medical education. In addition, the procedure for measuring diagnostic performance appears to be valid and to provide a simple means of measuring curriculum effects. It remains to be seen whether the findings would be replicated when students are allowed to freely gather data in open interaction with patients rather than respond to written presentations of cases.

The influence of medical expertise, case typicality, and illness script component on case processing and disease probability estimates

The present study investigated the influence of medical expertise, case typicality, and illness script component (enabling conditions vs. consequences) on the speed of case information processing and subjective disease probabilities. It was hypothesized that expert subjects would process case information faster than nonexpert subjects, that typical information would be processed faster than atypical information, and that an interaction would be found between expertise level, typicality, and illness script: Experts were expected to be sensitive to typicality of both illness script components, while advanced students would be sensitive only to typicality of consequences. This sensitivity would also be reflected in assigned probability estimates. The data supported the predictions concerning the effects of expertise level and typicality; it was also found that expert physicians are particularly sensitive to a combination of prototypical enabling conditions and prototypical consequences. Implications of these results for the illness script theory are discussed.

Comparative study of medical education as perceived by students at three Dutch universities

Objective. The aim of the present study was to identify the differences that may exist in professional satisfaction and skills (clinical patient management and psychosocial skills) in students and graduates from two traditional medical schools and their counterparts from a problem-based medical school in the Netherlands. Also their satisfaction for their training was investigated. Method. Questionnaires were designed containing items reflecting the earlier mentioned differences between the students. Following an initial pilot study, the questionnaire used in this study was constructed accordingly. Sample. The questionnaires were sent to 180 near and recent graduates of these three schools. Results. A total of 127 questionnaires were returned (response rate of 70.5%). The students of the PBL curriculum felt better prepared in psychosocial and interpersonal skills. They felt more satisfied with their training, but were less enthusiastic with the profession. The results also suggest that in their own opinion students and graduates from the three schools do not differ in clinical patient management skills acquired in medical school. Conclusion. A limitation of this study lies in the fact that results are based on actual self-assessment of the students. One must be aware that self-assessment does not always provide for objective information. However, since this limitation applied equally to respondents of all three medical schools, the differences between the schools can be considered indicative of the effects resulting from the different curricula.

On the origin of intermediate effects in clinical case recall

In two experiments, the effects of level of medical expertise and study time on free recall of a clinical case were assessed. In Experiment 1, a nonmonotonic relationship between level of expertise and recall was found: Subjects of intermediate levels of expertise remembered more information from the case than both experts and novices. This "intermediate effect" disappeared, however, when study time was restricted. Analysis of post hoc acquired protocols of pathophysiological knowledge active during case processing suggested that this phenomenon could be attributed to the nature of the pathophysiological knowledge mobilized to comprehend the case. In Experiment 2, this assumption was directly tested by priming relevant pathophysiological knowledge for either a short or a longer period, before enabling subjects to study the case briefly. Free-recall data confirmed and extended the results of Experiment 1. Again, an intermediate effect was found; this time, however, it was generated experimentally. The findings were interpreted in terms of qualitative differences in the nature of the knowledge structures underlying performance between novices, advanced students, and medical experts: Experts use knowledge in an encapsulated mode while comprehending a case, whereas students use elaborated knowledge.

A cognitive perspective on medical expertise: theory and implication

A new theory of the development of expertise in medicine is outlined. Contrary to existing views, this theory assumes that expertise is not so much a matter of superior reasoning skills or in-depth knowledge of pathophysiological states as it is based on cognitive structures that describe the features of prototypical or even actual patients. These cognitive structures, referred to as "illness scripts," contain relatively little knowledge about pathophysiological causes of symptoms and complaints but a wealth of clinically relevant information about disease, its consequences, and the context under which illness develops. By contrast, intermediate-level students without clinical experience typically use pathophysiological, causal models of disease when solving problems. The authors review evidence supporting the theory and discuss its implications for the understanding of five phenomena extensively documented in the clinical-reasoning literature: (1) content specificity in diagnostic performance; (2) typical differences in data-gathering techniques between medical students and physicians; (3) difficulties involved in setting standards; (4) a decline in performance on certain measures of clinical reasoning with increasing expertise; and (5) a paradoxical association between errors and longer response times in visual diagnosis.

Contextual factors in the activation of first diagnostic hypotheses: expert-novice differences

According to Feltovich & Barrows (1984), the general frame used by medical experts to construct a mental representation of a particular patient problem contains a component part for those illness features that are associated with the acquisition of the illness. These 'enabling conditions' are related in several ways to the patient's disease. Examples are conditions like sex and age, or risk factors originating from work, behaviour and hereditary taint. Because of the sequential nature by which patient data become available during a clinical interview, contextual information is expected to play an important role in the generation of initial diagnostic hypotheses. To investigate the hypothesis that experienced doctors better utilize this kind of information, a group of 18 experts and 17 novices was confronted with 32 short case histories each presented on three slides: a portrait of the patient, the patient chart containing previous disease history, and a slide with the presenting complaint. It was hypothesized that differences in the number of correct diagnoses would emerge between the two groups, because the experts would use the contextual information, implicitly provided by picture and patient chart, in a more extensive way. If so, this would show in the amount of information that is explicitly recalled later. The data confirmed these predictions. The experts produced almost 50% more correct hypotheses as compared to the novices and were able to reproduce a larger amount of contextual information in particular information that was directly relevant to the patient's problem. Only the expert group showed a high correlation between accuracy of diagnoses and recall measures.

Problems of research into medical problem solving: some remarks on theory and method

Investigators of medical problem solving, and of problem solving in general, appear to use the term problem solving to denote different concepts. Medical problem solving sometimes refers to the doctor solving the patient's problem, whereas others use it to refer to the doctor solving his own diagnostic problem. Second, 'problem' is used by some in a subjective sense (something is only called a problem if the subject has difficulties with it), and by others in an objective sense (problem being nearly synonymous with task). Finally, there is the definitional question of whether knowledge and problem solving are regarded as independent or as intimately related. What one means by problem solving, with one's research objectives (research may be aimed at medical education, medical practice or cognitive theory), constitute the major determinants of the choice of research design. It is advocated that investigators, before selecting a research design, should clarify their own definitions and research objectives, and before adopting other investigators' definitions and research designs, should consider carefully their research objectives.