Informing the teaching process: lessons from the educational sciences

Until recently, most medical educators emphasized the art of medical education and largely ignored the fundamental science of learning underlying their basic practices. However, over the last decade medical education has evolved into an academic discipline in its own right, where scholarship can be demonstrated in the generation of new knowledge or the development of more efficient or effective strategies for transferring knowledge to others. It is essential that all medical educators familiarize themselves with the fundamental literature of the learning sciences and build upon it as it applies to their individual practices as medical teachers. Recent developments in the discipline of medical education and their implications for teaching will be the focus of this year's Ideas for Medical Education column. As associate editor for 1999, the author of this paper describes the problems associated with mastering the scientific underpinnings of medical education and outlines the kinds of questions that will be addressed in the Ideas feature throughout the year.

Diagnostic value of tissue polypeptide-specific antigen (TPS) in neuroblastoma and Wilms' tumour

Although tissue polypeptide-specific antigen (TPS) has been described as a potentially useful serum marker of tumour activity in adult epithelial tumours, few data are available for childhood malignancies. Neuroblastomas and Wilms' tumours are the commonest types of solid malignancies found in the retroperitoneum of children. At this time, a widely used marker for Wilms' tumour is not available. Using an enzyme-linked immunosorbent assay (ELISA) kit, serum TPS levels in 23 children with neuroblastomas, nine with Wilms' tumours and 22 with benign tumours were evaluated to test the usefulness of the marker in identifying malignancies. Compared with healthy children (n = 110), the preoperative least-square means (LSM) of serum TPS were considerably elevated in both neuroblastoma (LSM = 209 U l(-1)) and Wilms' tumour (LSM = 235 U l(-1)), whereas values in benign tumours were only slightly elevated. Although the Wilms' tumours were associated with higher preoperative serum TPS levels, there was no statistically significant difference compared with neuroblastomas. Receiver operating characteristic analysis (ROC curves) showed a high sensitivity and specificity for both malignancies. Successful treatment resulted in decrease in TPS serum values. Serum TPS measurements in children presenting with abdominal masses can help in diagnosing the two commonest extracranial solid malignancies of childhood. Furthermore, TPS could acquire a pivotal role in monitoring therapy.

Safety and effectiveness of nurse telephone consultation in out of hours primary care: randomised controlled trial. The South Wiltshire Out of Hours Project (SWOOP) Group

OBJECTIVE

To determine the safety and effectiveness of nurse telephone consultation in out of hours primary care by investigating adverse events and the management of calls.

DESIGN

Block randomised controlled trial over a year of 156 matched pairs of days and weekends in 26 blocks. One of each matched pair was randomised to receive the intervention.

SETTING

One 55 member general practice cooperative serving 97 000 registered patients in Wiltshire.

SUBJECTS

All patients contacting the out of hours service or about whom contact was made during specified times over the trial year.

INTERVENTION

A nurse telephone consultation service integrated within a general practice cooperative. The out of hours period was 615 pm to 1115 pm from Monday to Friday, 1100 am to 1115 pm on Saturday, and 800 am to 1115 pm on Sunday. Experienced and specially trained nurses received, assessed, and managed calls from patients or their carers. Management options included telephone advice; referral to the general practitioner on duty (for telephone advice, an appointment at a primary care centre, or a home visit); referral to the emergency service or advice to attend accident and emergency. Calls were managed with the help of decision support software.

MAIN OUTCOME MEASURES

Deaths within seven days of a contact with the out of hours service; emergency hospital admissions within 24 hours and within three days of contact; attendance at accident and emergency within three days of a contact; number and management of calls in each arm of the trial.

RESULTS

14 492 calls were received during the specified times in the trial year (7308 in the control arm and 7184 in the intervention arm) concerning 10 134 patients (10.4% of the registered population). There were no substantial differences in the age and sex of patients in the intervention and control groups, though male patients were underrepresented overall. Reasons for calling the service were consistent with previous studies. Nurses managed 49.8% of calls during intervention periods without referral to a general practitioner. A 69% reduction in telephone advice from a general practitioner, together with a 38% reduction in patient attendance at primary care centres and a 23% reduction in home visits was observed during intervention periods. Statistical equivalence was observed in the number of deaths within seven days, in the number of emergency hospital admissions, and in the number of attendances at accident and emergency departments. Conclusions Nurse telephone consultation produced substantial changes in call management, reducing overall workload of general practitioners by 50% while allowing callers faster access to health information and advice. It was not associated with an increase in the number of adverse events. This model of out of hours primary care is safe and effective.

Evaluating health care using goal attainment scaling

Goal attainment scaling, a way of evaluating the outcomes of care, was first discussed 30 years ago, but it is rarely used today. The author argues that the technique is particularly relevant to modern healthcare practice.

Psychological distress: linking impairment with disability in facial neuromotor disorders

The relationship between facial neuromotor system impairment, disability, and psychological adjustment is not well understood. This study was designed to explore the relation between impairment and disability and the impact of psychological adjustment on the relation for individuals with disorders of the facial neuromotor system. We studied outpatients (n=48; mean age, 49.0; SD=16.3; range, 18 to 84 years) with a facial neuromotor disorder and acute or chronic facial paralysis. Measures of impairment (Facial Motion Assay, House-Brackmann scale, and Facial Grading System), disability (Facial Disability Index, physical and social well-being subscales), and psychological adjustment (Beck Anxiety Inventory, Beck Depression Inventory) were administered. Bivariate correlations between impairment and disability measures indicated impairment was positively correlated with physical and social disability (r=0.44, p < 0.01; r=0.39, p < 0.05, respectively). Stepwise regression analysis to predict disability indicated physical disability was predicted by impairment and the interaction of impairment and psychological distress (R2=0.425; F=12.57; df=2, 34; p=0.002). Psychological distress, and not impairment and the interaction of impairment and distress, was the single predictor of social disability (R2=0.274; F=13.23; df=1, 35; p=0.001). Psychological distress was a moderator of the relation between impairment and physical disability and a mediator of the relation between impairment and social disability for individuals with facial neuromotor disorders. Assessment and interventions targeted for psychological distress in addition to interventions targeted for impairments appear warranted to effectively reduce the disability associated with facial neuromotor disorders.

Ganglioglioma and intractable epilepsy: clinical and neurophysiologic features and predictors of outcome after surgery

PURPOSE

To review the clinical, neurophysiologic, and radiological data of patients with ganglioglioma who had undergone evaluation and surgery in our Epilepsy Program.

METHODS

The medical and neurophysiologic records of 38 patients with intractable epilepsy and ganglioglioma were reviewed. Data underwent statistical analysis.

RESULTS

There were 28 temporal and 10 extratemporal resections, with a mean age at seizure onset of 10.5 years and mean age at surgery of 22 years. Five tumor resections performed earlier were recorded. Twenty-nine patients had auras and 20 had secondarily generalized seizures. All 28 patients with temporal tumor had complex partial seizures. Preoperative MRI demonstrated the tumor in 36 of 36 patients: 17 of 29 demonstrated gadolinium enhancement, and 17 of 36 had mass effect. Scalp interictal sharp waves were present in 32 patients, and in 15 they were multiregional. In two patients, scalp EEG seizure onset was from the hemisphere contralateral to the tumor. Postoperatively, 79% of patients (30 of 38) were seizure-free (Engel's class I) at 6 months, 72% at 1 year (26 of 36), and 63% at 2 years (20 of 32). Excellent outcome was associated with a lower age at operation (p = 0.008), shorter duration of epilepsy (p = <0.01), absence of generalized seizures (p = <0.01), and no epileptiform discharges on a postoperative EEG (p = 0.01).

CONCLUSIONS

Good surgical outcome is expected in patients with ganglioglioma despite years of medically resistant seizures. Good outcome may be achieved despite EEG findings that may conflict with tumor location, and is more likely when surgery is performed relatively soon after epilepsy onset.

Electrical stimulation of the septal region of aged rats improves performance in an open-field maze

Memory deficits of age and disease may result from dysfunction of septohippocampal structures. Electrical brain stimulation might ameliorate these memory deficits. We show here that septal stimulation of very old rats leads to a marked and progressive improvement in performance in an open-field maze task. Unilateral stimulation of the perforant path is less effective. The frequency of stimulation is important: stimulation at 5 Hz and 50 Hz is effective, whereas stimulation at 0.5 Hz is less effective (though still significantly better than control). Hippocampal (dentate) EEG does not change significantly with septal stimulation frequency. These results may bear on the memory deficit of old age in humans. The results may also bear on the memory deficits seen in human disease states such as Alzheimer's disease.

Synthetically modified cellulose: an alternative to synthetic membranes for use in haemodialysis?

Renal replacement therapy relies predominantly on the use of cellulose-based membranes. Such membranes have a biocompatibility profile which is inferior to membranes manufactured from synthetic polymers. Synthetically modified cellulose (SMC) is a new, low-flux haemodialysis membrane in which hydroxyl groups have been replaced with benzyl groups. The biocompatibility profile characterized by changes in white cell and platelet counts and the activation of complement components (C3a, C5a and C5b-9) have been studied in vivo and compared with those of cellulose acetate, unmodified cellulose (Cuprophan ) and low-flux polysulphone (Fresenius Polysulfone) in the same group of patients. For SMC, the white cell count at 15 min declined to 65.6% of pretreatment level, compared with 63.8% for the cellulose acetate, 79.6% for low-flux polysulphone and 28.1% for Cuprophan, thereafter returning to pretreatment levels. Both modified cellulose membranes were superior to unmodified cellulose (P = 0.001); the differences between the modified cellulose membranes were not significant statistically. The changes induced by all three cellulose-based membranes exceeded those for low-flux polysulphone (P = 0.001). Associated with the neutropenia was a reduction in platelet count, but this was independent of membrane type. The mean time-averaged concentrations of C3a(des Arg) over 150 min were 1168 ng ml(-1) (SMC), 1030 ng ml(-1) (cellulose acetate), 1297 ng ml(-1) (Cuprophan) and 790 ng ml(-1) (low-flux polysulphone). Equivalent values for C5a(des Arg) were 6.12 (SMC), 2.98 (cellulose acetate), 11.03 (Cuprophan) and 1.33 ng ml(-1) (low-flux polysulphone). C5b-9 values were 385 (SMC), 386 (cellulose acetate), 177 (Cuprophan) and 185 ng ml(-1) (low-flux polysulphone). For each of the complement components the differences between the membranes were significant [P = 0.0009 (C3a(des Arg)), P = 0.0001 (c5a(des Arg) and C5b-9)]. The levels of C5b-9 generated during dialysis also showed a significant positive correlation compared to C5a for all membranes considered as a single group (Pearson's correlation coefficient = 0.870, P = 0.0001). It is concluded that the modification of the cellobiosic unit is a promising approach to improve the biocompatibility profile of cellulose-based membranes. The two different methods of modification lead to similar improvements in biocompatibility compared with unmodified cellulose, but as yet do not match that of low-flux polysulphone.

Preference for Noise and Effectiveness of Studying

The hypothesis that studying was equally effective in an environment with a preferred versus a nonpreferred amount of noise was tested. University students' preference for noise ( N = 112) was measured with ratings on Weinstein's Noise Sensitivity Scale and responses to seven questions about study habits. A month later, 20 students who reported a preference for noise and 20 students with a preference for quiet studied in a room in which there was noise (recorded cafeteria noise, 75 dB) and in quiet (50–55 dB) on two separate days. Within each preference for noise condition, the order of exposure to noise and to quiet was counterbalanced. An analysis of variance of accuracy scores on tests of reading comprehension indicated no significant difference between conditions. The interaction effect between preference for noise and conditions of noise was also not significant.

Migration trends in British rural areas from the 18th to the 20th centuries

"Longitudinal residential histories are used to examine the extent to which three rural areas in Britain had distinctive migration histories from the 18th to the 20th centuries. Migration flows into and out of the regions are used to examine the extent to which the regions were integrated into the British migration system, and the relative importance of rural to urban migration is assessed.... Analysis reveals a high degree of short-distance mobility within regions and emphasises the dominance of London in longer-distance migration.... It is also suggested that the role of towns in the migration system has previously been overemphasised, with much migration taking place between small settlements and some movement from large cities to smaller towns and villages.... The analysis challenges some accepted notions about migration in the past, and contributes to the debate about the extent to which British regions became part of a national economic and social system from the 18th century."

Putting clinical & financial reports on line

Healthcare Informatics has been following the progress of Sarasota Memorial Hospital's search for IT solutions with great interest--ever since the hospital innovative "Sarasota Summit" held in May 1994. Now, two years after the legendary brainstorming session among 10 of the nation's top healthcare CIOs--attended by more than 250 hospital personnel, consultants and members of the press and general public--SMH is busily implementing new components of the hospital's resulting information system redesign. On the following pages, SMH Vice President and CIO Jim Turnbull describes the hospital's new centralized electronic repository for information from medical records and patient accounting. Watch for another update soon as Healthcare Informatics continues to observe SMH's transition as influenced by Turnbull's unique approach to information system selection.

Performance-based assessment of clinical ethics using an objective structured clinical examination

PURPOSE

To further examine the objective structured clinical examination (OSCE) as a performance-based assessment method for clinical ethics.

METHOD

In the spring of 1993, a volunteer sample of 88 final-year medical students from all five Ontario medical schools took a four-station OSCE that used standardized patients and involved decisions to forego life-sustaining treatment. Performance was scored on a checklist of behaviors unique to each case. Data were analyzed for reliability using intraclass correlation coefficients and the Spearman-Brown prophecy formula.

RESULTS

Reliability of the test was only .28 as a result of a low average inter-station correlation of .07. To achieve a test reliability of .8, 41 stations (almost seven hours of testing time) would be required.

CONCLUSION

Because of its low test reliability, the OSCE is not a feasible stand-alone method for summative evaluation of clinical ethics. This performance-based evaluation method should be combined with other, more reliable evaluation methods. The OSCE has promise for formative evaluation.

Identification of active site residues of chorismate mutase-prephenate dehydrogenase from Escherichia coli

Chemical modification studies of the bifunctional enzyme chorismate mutase-prephenate dehydrogenase and mass spectral analysis of peptide fragments containing modified residues are presented. The reaction with diethyl pyrocarbonate (DEPC) results in the modification of several enzymic groups, including a single histidine group essential for dehydrogenase activity and a single lysine residue essential for mutase activity. This conclusion is based on the following evidence. (1) Hydroxylamine rapidly restores dehydrogenase activity to the DEPC-inactivated enzyme without restoring mutase activity. (2) Mutase activity is also lost upon treatment of the enzyme with trinitrobenzene sulfonate. (3) The reactivity of the dehydrogenase to DEPC increases with pH, suggesting the participation of a group with a pKa of 7.0 in the dehydrogenase reaction. (4) Two peptides identified by differential peptide mapping had mass values matching those calculated for peptides comprising residues 127-135 (containing His131) and residues 36-48 (containing Lys37). In support of the idea that the residues being modified are within the active sites, we show that the substrates prephenate and nicotinamide adenine dinucleotide (NAD+) offer protection against inactivation of dehydrogenase activity while inactivation of mutase activity can be prevented by prephenate and a transition state analogue (3-endo-8-exo)-8-hydroxy-2-oxabicyclo[3.3.1]-non-6-ene-3,5-dicarboxylic acid (endo-oxabicyclic diacid). Lys37 is conserved among several chorismate mutases and may participate in catalysis by interacting with an ether oxygen between C-5 and C-8 of chorismate in the transition state. His131 may be assisting in a hydride transfer from prephenate to NAD+ in the dehydrogenase reaction.

Temporal arteritis and polymyalgia rheumatica: nosographic and nosologic considerations

Original reports on temporal arteritis and polymyalgia rheumatica were reviewed before and after the introduction of steroid therapy to prevent blindness in temporal arteritis. In some cases, the original data were reworked. There is evidence that both diseases have become more benign. As a result, the perceived risk of blindness is presently overestimated, as is the perceived benefit of steroids in reducing this risk, and neither should be used as support for an essential difference between temporal arteritis and polymyalgia rheumatica. Indeed, no qualitative differences otherwise exist and both are best viewed as facets of a common disease spectrum with variable risk of adverse outcome. Some of the difficulties in dealing with diseases characterized by variable risk within present dichotomous classifications are discussed. It is likely that in many patients benign disease is presently undiagnosed. It is likely that certain classifications of temporal arteritis and polymyalgia rheumatica now in use lead to an overtreatment of some patients with relatively benign disease.

Content specificity and oral certification exams

This study reports on the generalizability of different skills assessed in the oral certification examinations in Internal Medicine of the Royal College of Physicians and Surgeons of Canada. Assessments from the 1992 examination were examined prospectively to determine (i) inter-rater reliability, (ii) correlation from morning to afternoon sessions, and (iii) overall test reliability. While inter-rater reliability was acceptable and in the range reported from previous studies, the generalizability across sessions was very low, ranging from 0.30 to 0.47, presumably reflecting content specificity. As a consequence, the overall test reliability was low, ranging from 0.57 to 0.69. Collapsing the overall scores into three decision categories (pass, borderline, fail) lowered the test reliability still further. Strategies to resolve this problem are suggested.

Evaluating communication skills in the OSCE format: reliability and generalizability

In most objective structured clinical examinations (OSCEs), communication skills are assessed as an 'add-on' to history-taking stations, rather than in stations designed to assess communication skills in the broadest sense. This study investigated the feasibility of developing such stations. In part one, 60 clinical clerks and 36 residents were rated in four 10-min emotionally charged situations portrayed by standardized patients. Inter-rater reliability was demonstrated (r = 0.59-0.63) and a highly significant effect of educational level was found. Generalizability between communication stations was low (0.17-0.20). Several explanations for poor generalizability, including poor discrimination as a result of low score variance and the confounding effect of content knowledge, were addressed in part 2. Ninety-five final-year medical students participated in an OSCE in which six 10-min encounters examined the students' ability to manage difficult emotional situations such as fear, anxiety, mania, sadness, confusion and anger. Half the students encountered a patient with moderate emotional symptoms and half an extreme emotional state. For difficult stations, students' scores were lower and standard deviation higher, suggesting that manipulating difficulty increases score variance and potentially discrimination. However, a strong interaction was found between difficulty and station content, and communication scores were highly correlated with content. Scenarios which created major communication difficulties (such as mania) resulted in much larger differences in scores between the easy and difficult versions. Communication OSCE stations can be created with acceptable reliability including difficult cases which address communication skills beyond simple history taking. Nevertheless, a generalizable set of communication skills remains elusive.