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Biomedical subjects

Lee R Brooks

Publications and source records attributed to Lee R Brooks.

13 recordsLinked to original sources
PubMed2007

The role of biomedical knowledge in diagnosis of difficult clinical cases.

Although biomedical knowledge is believed to be of little value in diagnosis of routine clinical cases, studies of clinical reasoning have found that physicians revert to use of basic biomedical knowledge when faced with challenging clinical problems. The current paper presents two experiments that empirically examine the role of biomedical knowledge in diagnosis of difficult cases by novice diagnosticians. Novices are taught to diagnose a series of artificial diseases using either knowledge of causal mechanisms or a list of clinical features. In Experiment 1, participants are then tested on two types of clinical challenges: (1) case summaries with irrelevant findings; (2) cases using unfamiliar terminology. Participants with an understanding of underlying mechanisms out performed their counterparts on both types of cases. In Experiment 2, participants are tested 1 week after initial training. Participants with knowledge of causal mechanisms were found to do better on cases with unfamiliar terminology. The results of the two studies provide additional support for the critical role of biomedical knowledge in diagnosis of difficult clinical cases.

Analysis of Variance↗
PubMed2006

Instantiated features and the use of "rules.".

Classification "rules" in expert and everyday discourse are usually deficient by formal standards, lacking explicit decision procedures and precise terms. The authors argue that a central function of such weak rules is to focus on perceptual learning rather than to provide definitions. In 5 experiments, transfer following learning of family resemblance categories was influenced more by familiar-appearing features than by novel-appearing features equally acceptable under the rule. This occurred both when rules were induced and when rules were given at the beginning of instruction. To model this and other phenomena in categorization, features must be represented on 2 levels: informational and instantiated. These 2 feature levels are crucial to provide broad generalization while reflecting the known peculiarities of a complex world.

Analysis of Variance↗
PubMed2006

Producing biased diagnoses with unambiguous stimuli: The importance of feature instantiations.

In this article, the authors demonstrate a laboratory analogue of medical diagnostic biasing (V. R. LeBlanc, G. R. Norman, & L. R. Brooks, 2001) in 2 experiments and explore the basis of this effect. Before categorizing novel exemplars, participants first evaluated the likelihood that the item was a member of the category suggested on that trial: either the correct category or a plausible alternative category. This was sufficient to produce a substantial bias toward the suggested category despite the use of unambiguous stimuli, explicit rules, and unhurried conditions--each of which would be likely to limit diagnostic bias. The authors argue that the production of this effect requires distinguishing between particular feature instantiations and more abstract representations of those features as well as allowing people to adopt a particular decision strategy mediating the use of instantiated features: a feature-recognition heuristic.

Association Learning↗
PubMed2006

Giving learners the best of both worlds: do clinical teachers need to guard against teaching pattern recognition to novices?

PURPOSE: There has been much debate in the medical education literature regarding the extent to which feature-driven and nonanalytic (similarity-based) reasoning strategies define expertise, but the relative value of teaching these strategies, together or in isolation, remains uncertain. The purpose of this study was to compare the diagnostic accuracy achieved upon receiving instruction to use each strategy in isolation to that of a combined approach. METHOD: In 2003-04, 48 undergraduate psychology students from McMaster University in Ontario, Canada, were taught to diagnose ten cardiac disorders (including normal) via electrocardiogram (ECG) presentation. Twelve students were instructed to carefully identify all features present before assigning a diagnosis (feature first). Twelve were given the same instruction with notice that some test ECGs had been seen during training (implicit combined). Twelve were simply instructed to trust familiarity and diagnose based on this impression (similarity-based). Finally, 12 students were given feature first and similarity-based instructions in combination (explicit combined). RESULTS: No difference in diagnostic accuracy was observed between the groups given the feature first (42%) and first impression (41%) instructions (p > .4), but the groups instructed to use both strategies (explicitly or implicitly) performed significantly better (56% and 53%, respectively; p < .01). CONCLUSIONS: The results support an additive model of clinical reasoning in which instructions to be feature oriented and to trust similarity improve performance in novice diagnosticians.

Adult↗
PubMed2006

Speed kills? Speed, accuracy, encapsulations and causal understanding.

BACKGROUND: The role of basic science, which provides causal explanations for clinical phenomena in medical education, is poorly understood. Schmidt has postulated that expert clinicians maintain this knowledge in 'encapsulated' form, indexed by words or phrases describing the processes. In the present paper we show that students who learn causal explanations have a more coherent understanding of the relation between diseases and clinical features which, in turn, influences recognition of words or phrases describing 'encapsulated knowledge' and the ability to maintain performance under speeded conditions. HYPOTHESES: In comparison to students who simply learn the features of 4 diagnostic categories, students who learn a causal explanation will: (a) recognise words describing encapsulated knowledge more accurately and (b) maintain or improve diagnostic performance under speeded conditions. METHODS: Two studies were conducted involving 4 'pseudo-endocrinology' diseases and undergraduate psychology students. One group learned signs and symptoms alone; the second group also learned a causal explanation. In study 1, they were then given a recognition memory task. In study 2, they were asked to diagnose new cases either (i) as quickly as possible or (ii) taking their time. RESULTS: In study 1, while there was no difference in recognising old words (90% versus 91%), the causal group was better able to recognise encapsulated and novel consistent words (50% versus 41%) (P = 0.02). In study 2 there was an interaction; causal students performed better under speeded conditions (71% versus 66%) but worse under thoroughness conditions (67% versus 73%), as predicted. CONCLUSIONS: Causal understanding leads to more coherent understanding of clinical conditions, which in turn leads to expert-like behaviour.

Clinical Competence↗
PubMed2005

The blossoms and the weeds.

As attested by the articles in this issue and the papers given at the festschrift, I have had the privilege of working with a talented group of people. In this article, a critique is given on the bouquet of themes that have bound many of us together, sorting the blossoms from some of the weeds. A brief description is then given of how these themes are working out in our current research on categorization.

Cognition↗
PubMed2005

The value of basic science in clinical diagnosis: creating coherence among signs and symptoms.

BACKGROUND: We investigated whether learning basic science mechanisms may have mnemonic value in helping students remember signs and symptoms, in comparison with learning the relation between symptoms and diagnoses directly. PURPOSE: To compare 2 approaches to learning diagnosis: learning how features of various conditions relate to underlying pathophysiological mechanisms and learning the conditional probabilities of features and diseases. METHODS: Undergraduate students (n = 36) were taught 4 disorders (upper motor neuron lesion, lower motor neuron lesion, neuromuscular junction disease and muscular disease), either using basic science explanations or (symptom x disease) probabilities. They were tested with diagnostic cases immediately after learning and 1 week later. RESULTS: On the immediate test, there was no difference in the results. One week later, the accuracy of the mechanism group remained at 0.52, but the performance of the probability group had dropped to 0.43. CONCLUSIONS: Knowledge of basic science may have value in clinical diagnosis by helping students recall or reconstruct the relationships between features and diagnoses.

Clinical Competence↗
PubMed2004

Using comprehensive feature lists to bias medical diagnosis.

Clinicians routinely report fewer features in a case than they subsequently agree are present. The authors report studies that assess the effect of considering a more comprehensive description than physicians usually offer. These comprehensive descriptions were generated from photographs of dermatology and internal medicine and were complete and accurate. Groups of clinicians of varying expertise were asked to offer a diagnosis based solely on the comprehensive verbal description. This initial exercise decreased the subsequent diagnostic acumen of experienced participants with the photographs relative to a group that initially diagnosed from the photographs. Reasons that the initial consideration of a list of features, all of which are present in the photograph, would decrease diagnostic accuracy are discussed.

Dermatology↗
PubMed2004

Limiting the playing field: does restricting the number of possible diagnoses reduce errors due to diagnosis-specific feature identification?

INTRODUCTION: Diagnostic hypotheses influence the identification of clinical features by medical trainees. This influence is strong enough to lead students to interpret features incorrectly if the initial diagnostic suggestion is incorrect. In the present study, we investigated whether reducing the pool of possible diagnoses at the time of test to a few highly plausible alternatives would focus the search for and interpretation of clinical features on a few alternative diagnoses and, as a result, reduce the influence of an initial diagnostic hypothesis on feature identification. METHODS: Naive students were taught 10 electrocardiographic (ECG) diagnoses. At test, they were asked to report all features visible on new ECGs. The test ECGs were presented with the suggestion of a tentative diagnosis (either the correct diagnosis or a plausible alternative) under 2 conditions: students were either instructed that the ECG represented one of 3 possible diagnoses (which were explicitly mentioned), or they were instructed that the ECG might represent any of the 10 diagnoses learned. RESULTS: Students' identification of the ECG features was strongly influenced by the diagnostic suggestion. Reducing the number of alternatives available at the time of test did not reduce the impact of a diagnostic suggestion on feature interpretation. DISCUSSION: Increasing the salience of alternative hypotheses does not reduce the impact of a diagnostic suggestion on the interpretation of clinical features.

Bias↗
PubMed2003

Practice makes perfect: the critical role of mixed practice in the acquisition of ECG interpretation skills.

PURPOSE: To examine the effect of instructional format on medical students' learning of ECG diagnosis. METHOD: Two experiments employed different learning and practice methods. In the first, students were randomly allocated to one of two instructional approaches, one organized around features (e.g., QRS voltage) and the other around diagnostic categories (e.g., bundle branch blocks), followed by a practice phase. In the second experiment, the instruction was standardized, and students were randomly allocated to one of two practice phases, either "contrastive" where examples from various categories are mixed together, or "non-contrastive" where all the examples in a single category are practiced in a single block. RESULTS: In the first experiment, there was no significant differences in students' diagnostic accuracy on novel ECG examples. In the second experiment, students exposed to the contrastive approach in the practice phase had superior diagnostic accuracy (46%) compared to 30% accuracy for the non-contrastive session, p < 0.05). CONCLUSION: These experiments highlight two important features in the design of instructional materials. First, learning around the features of the problem (analogous to problem-based learning) may have no advantages over learning the category. Second, the design and organization of deliberate practice can result in significant learning gain.

Canada↗
PubMed2003

The privileged status of prestigious terminology: impact of "medicalese" on clinical judgments.

PURPOSE: Health professionals frequently use medical terminology like dyspnea or nasopharyngitis. These two studies examine how the use of medical terms affects the judgments of seriousness, prevalence, and disease; and diagnostic judgments. METHOD: In study 1, a survey containing the names of 22 diseases with either a medical or lay description was completed by 47 undergraduate psychology students and 25 medical students, who were asked to judge seriousness, prevalence, and how "disease-like" it was. In study 2, undergraduate students learned four "pseudopsychiatry" conditions, each with four associated features. Features were presented in lay or medical versions. They were then tested with 18 new cases with two medical features from one condition and two lay terms from the other. RESULTS: In study 1, the medical students rated conditions as more disease-like, more serious, and less prevalent than did the psychology students. Medical descriptions were seen as significantly less common and somewhat more serious and more disease-like. In study 2, the participants rated the condition with medical features consistently more likely than the alternative, regardless of training condition. CONCLUSIONS: The specific words used to describe a feature or condition can have an impact on judgments of likelihood of disease, and, to a lesser extent, judgments of seriousness.

Diagnosis↗
PubMed2002

Expert-novice differences in memory: a reformulation.

BACKGROUND: One of the most discriminating measures of expertise in multiple domains has been performance on memory tasks. In medicine, however, the relation between expertise and memory is more equivocal. PURPOSE: To compare and contrast the sufficiency of multiple explanations of this finding by using three probes of memory rather than the traditional free recall task alone. METHODS: Students, residents, and internists were asked to read case histories and assign diagnoses before undertaking free recall, cued recall, and recognition tests. RESULTS: Students consistently outperformed internists. Resident performance was more variable. CONCLUSIONS: Our data appear to rule out (a) the notion that expert memory for cases takes on an encapsulated form, (b) the idea that experts simply say less than students in response to a free recall task, and (c) the possibility that experts attend differentially to highly diagnostic features. The results can best be explained by the idea that students process the featural details of a case history more elaborately than do expert diagnosticians who, instead, read medical cases more holistically.

Clinical Competence↗