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Rationale and aim The rapidly changing knowledge base of clinical practice highlights the need to keep abreast of knowledge changes that are most relevant for the practitioner. We aimed to develop a model for reflection on clinical practice that identified the key elements of medical knowledge needed for good medical practice. Method The dual theory of cognition, an integration of intuitive and analytic processes, provided the framework for the study. The design looked at the congruence between the clinical thinking process and the dual theory. A one-year study was conducted in general practice clinics in Oxfordshire, UK. Thirty-five general practitioners participated in 20-minute interviews to discuss how they worked through recently seen clinical cases. Over a one-year period 72 cases were recorded from 35 interviews. These were categorized according to emerging themes, which were manually coded and substantiated with verbatim quotations. Results There was a close fit between the dual theory and participants' clinical thinking processes. This included instant problem framing, consistent with automatic intuitive thinking, focusing on the risk and urgency of the case. Salient features accounting for these choices were recognizable. There was a second reflective phase, leading to the review of initial judgements. Conclusions The proposed model highlights the critical steps in decision making. This allows regular recalibration of knowledge that is most critical at each of these steps. In line with good practice, the model also links the crucial knowledge used in decision making, to value judgments made in relation to the patient.

The aim of this study was to determine the effect of a critical path analysis, used as a management tool, on the efficiency of clinical service delivery for patients with a fractured neck of femur. It is a before-and-after study of the medical records of all patients admitted between October 1992 and October 1993 with a primary diagnosis of fractured neck of femur, but excluding patients under 50 years old and those with multiple fractures or metastatic disease. Patients fell into two groups: those admitted in the six months before the introduction of a clinical management program based on a critical path analysis, and those admitted after the introduction of the program in April 1993 (88 program cases and 90 nonprogram cases). A medical records administrator blinded to the program category of the patients independently coded diagnostic data, while other data were abstracted from the clinical notes. The length of stay for a fractured neck of femur declined from a mean of 19.3 days to a mean of 11.0 days (P < 0.0001). The outcome measures were: the distance walked just before discharge from hospital, the discharge destination, and unplanned readmission. These did not change significantly, and the wound infection rate declined during the period of the intervention. The implementation of a clinical management pathway based on a critical path analysis dramatically reduced the length of stay for patients admitted with a fractured neck of femur while maintaining quality of outcomes. Critical path analysis is a useful management tool to improve the efficiency of certain clinical services.

Objective: To improve the quality of clinical care through better continuity of services between the public hospital and general practitioners (GPs), focusing on expediting discharge of patients from hospital through improved use of resources provided by GPs., Design: Stage 1: Participant observation during ward rounds and unstructured interviews to gain an understanding of the perceptions of hospital staff and GPs of the GP's role in the discharge process. Stage 2: Semi-structured interviews with registrars and GPs of 30 patients (who were admitted to a medical ward and discharged to the care of their GP) to get the participants' views of each other's roles in providing continuity of care., Results: There was a general lack of trust on both sides, and poor communication owing to several structural and perceptual problems. Registrars focused on specialist care and outpatient follow-up, being almost oblivious to GP functions, apart from monitoring the management plan developed in the hospital; they made no use of GPs' knowledge of the case or their experience in treating patients within their families and social milieu, and frequently wished to do everything within the hospital. GPs, on the other hand, often felt alienated from the hospital system, although they had much to offer by being able to contribute details of the patient's background and by using their special skills, which went well beyond passively monitoring progress., Recommendations: 1. Information about the patient's GP should be made available to hospital staff. 2. Interns should make telephone calls to GPs after admission and when the discharge date is known. 3. Early-discharge summaries should be forwarded and include: (i) reasons for giving or altering medications; (ii) specific plans after discharge; (iii) information conveyed to the patient and family about the illness; and (iv) a summary of the case by the consultant. 4. Registrars and interns should be educated about the appropriate involvement of GPs in the discharge process and throughout the patient's stay in hospital. 5. Direct involvement of the GP with the patient during hospital stay should be encouraged. 6. A pilot study should be set up to investigate the role of a liaison person in overcoming problems of the transition of care of hospitalised patients to the community.

This study looks at the relationship between anatomical concepts held by medical students and their clinical application, and develops a testable model of how students use basic science concepts for clinical problem-solving. According to the model, the essential prerequisites to solve a clinical problem using basic science information include the appropriate basic science knowledge, the ability to collect and interpret clinical information, with the key concept being the link that must then be made between clinical data and basic science. A detailed analysis of the individual components of the model should help to clarify and resolve some of the debate about the nature and balance of basic science and clinical education. A neurological diagnostic problem was used to test the assumptions of the model in a group of medical students who had minimal clinical experiences. There was no demonstrable relationship between anatomical knowledge as assessed by conventional tests and the diagnosis. There was a powerful relationship between measures of organization of knowledge and diagnosis, suggesting that the organization and development of concepts is the key to correct diagnosis. The findings have significant implications for assessment purposes and suggest that standard methods as generally practised may not measure the appropriate conceptual development and are not congruent with curricular objectives. Through the examination of its different learning outcome measures, the model may also be used to provide a profile of individual students or classes, which should help teachers and students deal with difficulties that may be experienced in learning to link clinical and basic science concepts.

Evaluation of a number of courses in clinical decision-making (CDM) indicates that there are well-defined problems in teaching this subject. This paper describes some of the difficulties and proposes appropriate remedies. Problems in teaching undergraduates are different from those in the postgraduate years. Three areas where the principles of CDM are particularly useful to undergraduates relate to the structuring of clinical problems, clarifying the place of value judgements and developing new concepts regarding test ordering, particularly the importance of false positive rates and the overwhelming power of prior probabilities. In postgraduate teaching the most important areas relate to the origin of probability and of utility estimates. The complexity of decision analysis also needs critical comment. Two remedies are suggested which will help course developers when faced with these problems. Firstly, the early introduction of concepts regarding sensitivity analysis, making it clear that with the aid of CDM we are able to deal with a wide range of probability estimates, precision rarely being required in clinical medicine. Secondly, the availability of educational support systems will help expert clinicians teach CDM concepts within their own field.

A condition commonly seen after motor vehicle accidents is studied. This is the "late whiplash" syndrome, which is defined as a collection of symptoms and disabilities seen more than six months after a neck injury occurring in a motor vehicle accident. A series of 300 cases is examined. With the use of factor analysis the syndrome is defined as consisting of headache, neckache, neck stiffness, and depression, as well as anxiety, all of which are strongly correlated with each other. There is, on the other hand, a poor correlation with physical or radiological abnormalities. The condition is common in women, especially in the 21 to 40 years' distribution. It is shown that social variables may be relevant n the production of the syndrome.

A condition commonly seen after motor vehicle accidents, the Late Whiplash Syndrome, which is defined as a collection of symptoms and disabilities seen more than six months after a neck injury occurring in a motor vehicle accident, is examined in a series of 300 cases. The author suggests that the development of the Late Whiplash Syndrome, some of whose characteristics are viewed as illness and some as illness behavior, depends on social variables. The differential distribution in Western countries and in Singapore is related to sanctions against entry into the sick role associated with this type of injury which are present in countries such as Singapore. Conversely, motor vehicle injury is legitimized in Western Countries such as Australia as an historical overview shows. The author's model of the Late Whiplash Syndrome lends itself to generalizations about the development of social illness in different cultures.

Clinicians are increasingly facing complex diagnostic problems in patients who have a pre-existing disease and in whom new symptoms develop which may be complications of that disease or manifestations of another, perhaps more common, condition. The neurological complications of malignancy fall into this situation. The results of diagnostic tests applied under these circumstances run the risk of being misinterpreted, largely due to lack of appreciation of the powerful effect of the pre-existing disease on a priori estimates of disease which enter the differential diagnosis. A bayesian analysis outlines the basic structure of these novel problems--a transient neurological disturbance in a man with lung cancer but a negative computerised tomographic scan illustrating the points. Bayesian probability revision yields accurate estimates of the predictive values of tests that tend to be different from those generated by intuitive clinical reasoning.

To assess the predictive value of prolongation of visual evoked response (VER) plus the presence of oligoclonal bands in the cerebrospinal fluid (CSF) in the diagnosis of multiple sclerosis (MS) in patients with isolated cord lesions, the false-positive rate for the two tests combined was determined by a prospective analysis of 42 patients with a structural spinal cord lesion. The false-positive rate for the combination of VER and CSF abnormalities was zero, but the individual false-positive rates were 10% for VER and 12% for CSF protein oligoclonal bands. According to Bayes' theorem, and taking into account the false-positive rates of the tests in the population studied and the prevalence of MS and the true-positive rates for the tests as derived from published reports, abnormalities of VER and CSF protein together gave a probability of MS of 100%. However, if only either the VER or the CSF were abnormal, the probability of MS was 44% or 49%, respectively. An abnormal result for both tests thus indicates a sufficiently high probability of MS to exclude myelography, but a positive result in only one test warrants the procedure.

The problem-solving strategies of fifth year medical students were studied using two simulated cases. One of these cases involved a neurological problem which was unfamiliar to the students. With the use of stimulated recall the study looked at the origin of the first hypothesis. The symptoms given by the patient did not trigger an appropriate hierarchy of questions and the students resorted to problem-solving techniques, such as drawing on commonsense. In some cases they matched symptoms against clinical cases they had seen previously. Recall from lectures was used occasionally. Instead of rational methods of hypothesis generation, they were most likely to be influenced by recent clinical exposures. Students having identical experiences may have had differing perceptions of these exposures. As a result, their early hypothesis formation showed marked individual variation. These findings need to be considered in the light of how students learn and the content of the teaching that is meaningful to them.

We report a hitherto poorly documented cause of failure of curriculum implementation. The case of the clinical training of foreign medical graduates (externs) in Hong Kong is used to illustrate problems that may arise in professional education where in-service work in institutions is part of the educational process. The example is particularly relevant to health professional education which generally involves a significant in-service component. We used participant observation, questionnaires and brief interviews to obtain data from 97 externs and 48 supervisors. The results indicated that between a third and a half of the externs did not receive experiences as designated in the curriculum. Apart from age, individual characteristics of the externs did not show statistically significant relationships to the kind of experience obtained. The major significant variable (P less than 0.01) was the type of hospital where the exposure was gained. In one type of hospital the externs shared the work-load, whilst in the other type they were largely used as observers with minor technical duties. The supervisors' perception of the externs' professional capabilities varied according to the hospital. We believe that the failure of curriculum implementation was related to conflict between institutional needs, which must be safeguarded by the supervisors, and the educational needs of the learners. This conflict affects the perceptions of the supervisors and without their full cooperation the curriculum cannot be delivered. The roles and perceptions of supervisor and learner must overlap sufficiently for the system to be effective and this must be taken into account by curriculum planners.

The decision to offer surgery or deep X-ray therapy to patients diagnosed as having malignant gliomas on CT scans is often problematical. Decision-tree analysis is used to make the underlying assumptions explicit in either strategy. Using biopsy and CT data obtained from our own experience, and survival figures from the literature, we are able to demonstrate that the decision is to a large extent related to value judgement. Specifically this relates to the assessment of the utility of long-term survival versus the immediate mortality and morbidity of biopsy in addition to possible difficulties in accepting long-term uncertainty of diagnosis if a biopsy is not performed.

This paper describes the evaluation of an innovative course in clinical decision-making (CDM). A traditional course in neurology taught concurrently to the same group of students by the same teacher was used for comparison. The aim of the course was to introduce students to the basic concepts of CDM as an aid to rational decision-making. The end-point of the evaluation was their perception of the immediate clinical relevance of CDM. It was postulated that by seeing this relevance they would be more likely to change their decision-making behaviour than by simply learning factual content or principles. The evaluation used an ongoing formative approach, including ethnographic analysis, questionnaires, small group discussion and supportive feedback for the teacher. The ongoing evaluation of the course resulted in revisions with increasing relevance within the students' level of experience, changes in sequence of presentations and encouragement of active student participation. A pre-test showed that students had difficulty in the correct assessment of the validity of data and in the correct revision of opinion. Results of the evaluation indicated that the CDM course did not achieve its objective of making students aware of the immediate clinical relevance of CDM. Possible reasons for this include the lack of reinforcement from clinicians suitable for modelling and the context specific nature of the learning of thinking processes. For a CDM course to be successful, it may need to be taught within the context of specific clinical topics. It is suggested that the evaluation approach used here is a cost-effective method when considering innovations in the curriculum and useful for generating further questions for study.

The incidence of headaches in well documented cases of cervical spondylosis with neurological disability was reviewed. This was compared to that in a series of cases with a clinical diagnosis of tension headache in order to determine if there were any identifiable differences between the two types of headache. Fifty-nine cases of cervical spondylosis were reviewed. Five of these patients had headaches. Fifty patients with tension headaches were also reviewed. No differences were seen when location or other qualitative features of the headaches were compared between the two groups of patients. We conclude that the incidence of headache is low in cervical spondylosis and that the pattern of headache has no features that distinguish it from that of tension headache, suggesting that the pathogenesis is similar. We therefore suggest that the basis of headache in patients with cervical spondylosis is secondary muscle contraction.

Twenty seven gastroenterologists (15 physicians and 12 surgeons) were studied to capture their policy in the usage and weighting of cues in making a diagnosis. This was a relatively small sample and on account of possible sampling bias only tentative generalisations will be made. Five case vignettes, each consisting of four to eight cues, were used. Subjects were asked to give their percentage likelihood estimates of various diagnostic possibilities after each cue. This gave an indication of their perception of the significance of various cues in relationship to each diagnosis. There were marked variations in cue weighting by these experts, and in particular, most individuals were far off the mean regarding the weighting of certain clinical features, thus displaying idiosyncratic behaviour in these instances. As may be expected, there were differences in disease prevalence estimates between physicians and surgeons. Early information had an overwhelming effect on the final diagnosis. In most cases the expert relied on a few critical cues rather than on a pattern to make a diagnosis. In view of the strong influences of early diagnostic formulations, these findings confirm the need for doctors to learn to use and collect accurate factual information on prevalence rates and on the most significant critical cues for various disease processes. The study highlights some of the problems faced by novices in learning from experts who may teach them contradictory information about what are the most significant factors in coming to a diagnosis.

With the use of Bayesian decision analytic techniques we assess the role of visual evoked response (VER) and cerebrospinal fluid (CSF) examinations in the investigation of patients with suspected singular spinal sclerosis. An abnormal VER increases the probability of multiple sclerosis by 50%. An associated CSF abnormality does not affect this probability. In a setting of a negative VER, CSF abnormalities increase the probability of multiple sclerosis by 27%. On currently available data, VER should therefore be the primary investigation in patients with suspected singular spinal sclerosis. If the result is abnormal myelography may be omitted. CSF examinations are only useful if VER facilities are not available.

A 57 year old man is described who presented with symptoms and signs suggestive of brachial neuritis. Sparing of the serratus anterior both clinically and on electromyography suggested that the lesion was in the brachial plexus, thus supporting the diagnosis. Subsequent investigation showed an extradural tumour at C5-C6 level. Sparing of serratus anterior does not definitively localize the pathology as distal to the nerve roots.

The aim of this study was to distinguish factors which may influence student perception of what constitutes a good introductory course in clinical neurology. This should lead to the development of improved teaching techniques. Previous work has shown that even those students who retain accessible knowledge of preclinical subjects, such as neuro-anatomy, find it difficult to use this in a clinical context. This study is preliminary to looking at correlations between student perception of what they like about a clinical topic and the ability to integrate clinical knowledge with pre-existing knowledge structures. The evaluation was carried out on 36 fifth year students who were taught clinical neurology in small groups concurrently with another topic, clinical decision making (CDM), by the same teacher. Neurology consistently rated at over 80% for enjoyment, interest and perceived clinical relevance. This contrasted with low ratings of less than 25% on all these parameters for CDM. An analysis of teaching methods showed that in neurology, contrasting with CDM, procedural rules were supplied for the application of preclinical knowledge at the bedside, students had an opportunity for active participation and problem solving in class, as well as frequent patient interaction. All these factors are important for student acceptance of a course, but further studies are needed to look at the interplay of preclinical knowledge and the acquisition of clinical expertise. The findings of this preliminary work may have significant implications for curriculum planners when developing introductory clinical courses.

A series is reported of 25 subjects with migraine, whose attacks on some occasions involved impairment of consciousness. The disorder did not necessarily involve younger people, or occur early in the course of the malady.

An analysis of the clinical features of patients having evidence of a syncopal onset to convulsive episodes is reported. The range of convulsive phenomena was quite wide and did not appear to differentiate the syndrome from primary epilepsy in terms of seizure morphology, occurrence of incontinence or pattern of post-ictal recovery. It is therefore suggested that the premonitory and precipitating features are more specific in the diagnosis of convulsive syncope. Skin pallor was often reported during attacks. Although EEG abnormalities were seen in some cases, the follow-up results indicate a low incidence of unprovoked convulsions in patients with this condition without anticonvulsant treatment.

Consideration of cerebral arteriovenous malformation (AVM) illustrates how decision analysis may be used to evaluate systematically two treatment options--surgery before bleeding occurs or conservative management. The analysis balances risk of immediate surgical mortality and morbidity against the delayed risks inherent in conservative management. Because the condition is rare and local experience therefore scant, probability estimates have to be obtained from the literature. From these probability estimates and from estimates of attractiveness of various outcomes (made in this study by a clinician) a quantitative assessment of the risks and benefits of surgical versus medical management can be calculated. The finding is that conservative treatment is preferable to surgery in patients who present with an AVM before bleeding occurs, even when the probability estimates used are those obtained under conditions more favourable to surgery. The decision also remains unchanged when different attractiveness values are assigned to possible outcomes.