Using a diary to quantify learning activities

BACKGROUND: Diaries of actual learning activities can fill the gap between the planned curriculum and students' opinions and outcomes. We report the development and validity of such a method, estimate sources of variation and model sampling strategies to determine efficient ways to obtain information about a curriculum or about individual students. METHODS: Following development and piloting, the diary was administered to fourth- and fifth-year medical students. Each student was asked to complete a diary on 3 randomly selected days of the academic year. Sources of variance and generalisability were determined using variance components analysis. Validity was explored by comparing activities with what is known about the curriculum, assessment, timetables and the 2 classes of students. RESULTS: Response rate was 83% (287/345). Learning activities varied as expected with timing of assessments, and on weekdays compared with weekends. For most activities, 14 days per student would be needed to obtain generalisable information about an individual student. The variation between days is greater than the variation between students, meaning that sampling for information on a curriculum should include all students and all days of the year but the number of diaries per student could be kept low depending on the desired power to detect any differences. CONCLUSION: Such an evaluation method is feasible and can provide reliable and valid information about study activities. Reasons for good compliance are discussed. Sampling strategies should be tailored to the purpose of the study.     

Competency-based assessment and cultural compression in medical education: lessons from educational anthropology

OBJECTIVE: This paper explores the thesis that medical education is the cultural transmission to learners of specific values, which are increasingly expressed as graduation competencies. As testing is a powerful way to transmit cultural values to learners in a brief period of time, competency-based assessments can be an instrument of cultural compression in medical education. METHODS: The author reviewed medical literature to illustrate the concepts from educational anthropology, led the process one medical school used to develop its list of graduation competencies, and conducted a citation search about competency domains. RESULTS: There is support in the literature for viewing medical education as an example of cultural transmission and compression and for the assertion that testing influences student behaviour. The graduation competency statements developed by the school reflect traditional and emergent values. The citation search data confirmed that some competency domains reflected traditional values, while others reflected more emergent values. CONCLUSION: Concepts from educational anthropology are relevant to medical education and provide perspectives for understanding contemporary issues such as competency-based assessments.     

A practical guide to assessing clinical decision-making skills using the key features approach

AIM: This paper in the series on professional assessment provides a practical guide to writing key features problems (KFPs). Key features problems test clinical decision-making skills in written or computer-based formats. They are based on the concept of critical steps or 'key features' in decision making and represent an advance on the older, less reliable patient management problem (PMP) formats. METHOD: The practical steps in writing these problems are discussed and illustrated by examples. Steps include assembling problem-writing groups, selecting a suitable clinical scenario or problem and defining its key features, writing the questions, selecting question response formats, preparing scoring keys, reviewing item quality and item banking. CONCLUSION: The KFP format provides educators with a flexible approach to testing clinical decision-making skills with demonstrated validity and reliability when constructed according to the guidelines provided.     

Postoperative changes of carpal canal pressure in carpal tunnel syndrome: a prospective study with follow-up of 1 year

Carpal canal pressures were measured in 103 patients with idiopathic carpal tunnel syndrome, before and after open release, with a postoperative follow-up of 1 year. Twenty-five normal subjects were used as controls. Pressures were measured with the wrists in three positions: neutral, full passive flexion and full passive extension. At each wrist position, the mean pre-operative pressures in the study group were significantly higher than in the control group. In both groups, the pressures were maximal with full passive extension and minimal in the neutral wrist position. Immediately after surgical release, there was a marked decrease of the carpal canal pressures. However, during the second postoperative month, there was a significant increase of the pressures at each wrist position, although these were still within the normal control range. This rise in pressures persisted to 12 months. These findings suggest that the carpal ligament reconstitutes by normal scar formation, but with lengthening such that the volume of the carpal canal is enlarged, so preventing a rise in pressure with return of the pre-operative problem.     

Evaluation of semiautomated measurements of mesothelioma tumor thickness on CT scans

RATIONALE AND OBJECTIVES: To evaluate the clinical acceptability of semiautomated methods for the measurement of mesothelioma tumor thickness in computed tomography (CT) scans. MATERIALS AND METHODS: A computer interface was developed to allow the acquisition of semiautomated mesothelioma tumor thickness measurements, which require the manual selection of a point along the outer margin of the tumor in a CT section. After application of an automated lung segmentation method, the computer automatically identifies a corresponding point along the inner margin of the tumor (as represented by the lung boundary), constructs a line segment between the manually selected outer tumor margin point and the computer-determined inner tumor margin point, and computes tumor thickness as the length of this line segment. Three radiologists and oncologists independently reviewed line segments representing the semiautomated measurements generated by three different algorithms at 134 measurement sites in the CT scans of 22 mesothelioma patients. The observers either accepted a measurement line segment or modified it through the interface. Differences between the initial semiautomated measurements and the measurements as modified by the observers were analyzed. RESULTS: The frequency with which observers accepted the semiautomated measurements without modification was as high as 86%. Of all measurements across all observers and methods (1,206 measurements), 89% were changed by 2 mm or less. CONCLUSION: We have developed semiautomated methods to measure mesothelioma tumor thickness. The potential of these methods has been demonstrated through an observer study. We expect these methods to become important tools for the efficient quantification of tumor extent.     

Method for cortical bone structural analysis from magnetic resonance images

RATIONALE AND OBJECTIVES: Quantitative evaluation of cortical bone architecture as a means to assess bone strength typically is accomplished on the basis of images obtained by means of dual-energy X-ray absorptiometry (DXA) or computed tomography. Magnetic resonance (MR) imaging has potential advantages for this task in that it allows imaging in arbitrary scan planes at high spatial resolution. However, several hurdles have to be overcome to make this approach practical, including resolution of issues related to nonlinear receive coil sensitivity, variations in marrow composition, and the presence of periosteal isointense tissues, which all complicate segmentation. The aim of this study is to develop MR acquisition and analysis methods optimized for the detection of cortical boundaries in such complex geometries as the femoral neck. MATERIALS AND METHODS: Cortical boundary detection is achieved by radially tracing intensity profiles that intersect the periosteal and endosteal boundaries of bone. Profiles subsequently are normalized to the intensity of the marrow signal, processed with morphologic image operators, and binarized. The resulting boundaries are mapped back onto the spatial image, and erroneous boundary points are removed. From the detected cortical boundaries, cortical cross-sectional area and thickness are computed. The method was evaluated on cortical bone specimens and human volunteers on the basis of high-resolution images acquired at a 1.5-Tesla field strength. To assess whether the method is sensitive to detect the expected dependencies of cortical parameters in weight-bearing bone on overall habitus, 10 women aged 46-73 years (mean age, 56 years) underwent the cortical imaging protocol in the proximal femur, and results were compared with DXA bone mineral density parameters of the hip and spine. RESULTS: Reproducibility was approximately 2%. Double oblique images of the femoral neck in the 10 women studied showed that cortical cross-sectional area correlated strongly with height (r = 0.88; p = .0008), whereas cortical diameter versus age approached significance (r = 0.61; p = .06). Measurements in specimens of some cortical parameters indicated resolution dependence. However, note that specimen ranking within each parameter remained constant across all resolutions studied. CONCLUSION: Data suggest the new method to be robust and applicable on standard clinical MR scanners at arbitrary anatomic locations to yield clinically meaningful quantitative results.     

Evaluation of satisfaction level by parents and children following pediatric anesthesia

BACKGROUND: Research in the field of patient satisfaction first took place in the 1980s in the USA, and later in Europe, aimed at meeting competitive requirements in the field of health care. Very few studies of this type exist in regard to pediatric anesthesia. Our aim was to develop a rapidly interpretable questionnaire to measure the level of parental satisfaction when their children undergo surgery and provide information on those factors triggering anxiety in these children. METHODS: Over a period of 18 months 179 parents of children in pediatric surgery responded to 214 questionnaires designed to investigate principally the emotional/behavioral spheres as well as the comfort provided. RESULTS AND CONCLUSIONS: We found that parents generally expressed a high degree of satisfaction which was good and correlated significantly with environmental comfort and postoperative observations performed by anesthetists and nursing staff. In the children, lack of fear at the moment of being anesthetized, and lack of anxiety on the day preceding surgery, were attributed to the serenity transmitted by the anesthetist and nurses. Significant anxiety resulted from the fear of an unpleasant impact with the operating room.     

Comparison of health-related quality of life questionnaires in ambulatory oncology

The purpose of this study is to compare three commonly used health-related quality of life (HR-QOL) questionnaires for their ease of use, accuracy, and patient preference; identify factors related to patient preference; identify differences in patient completion rates; and to identify factors associated with patient completion of these questionnaires. Three psychometrically sound measures, the Symptom Distress Scale (SDS), Medical Outcome Study Short Form-36 (SF-36), and Functional Assessment of Cancer Therapy (FACT), were tested. Seventy-nine patients completed questionnaires in the ambulatory oncology setting. No significant differences in patient ratings were found in ease of use and accuracy among the questionnaires. All of the questionnaires were rated as easy to use and accurate. Patient ratings on preference were marginally significant (p=0.07). Forty-six percent of participants indicated that they preferred the SDS, whereas 27 and 39 preferred the SF-36 and the FACT. No significant differences in patient completion rates were found among the questionnaires. One hundred percent completion rates ranged from 88.6 for the SDS to 78.5 for the SF-36, and 80 completion rates ranged from 98.7 for the SDS to 94.9 for the SF-36. Administration of standardized HR-QOL questionnaires is feasible in the clinical setting.This research was supported by an American Cancer Society Institutional Research Grant (IRG 58-012-42) through Yale Comprehensive Cancer Center and a grant from Bayer Pharmaceutical Company.     

Effects of stellate ganglion block on cerebral haemodynamics as assessed by transcranial Doppler ultrasonography

Background. Stellate ganglion block (SGB) causes vasodilatationin the skin of the head and neck because of regional sympatheticblock. Its effects on cerebral haemodynamics, in health or indisease, are not clear. We evaluated the effects of SGB on ipsilateralmiddle cerebral artery flow velocity (MCAFV), estimated cerebralperfusion pressure (eCPP), zero flow pressure (ZFP), carbondioxide reactivity (CO₂R) and cerebral autoregulation usingtranscranial Doppler ultrasonography (TCD). Methods. Twenty male patients, with pre-existing brachial plexusinjury, and undergoing SGB for the treatment of complex regionalpain syndrome of the upper limb, were studied. For SGB, 10 mlof plain lidocaine 2% was used and the onset of block was confirmedby presence of ipsilateral Horner's syndrome. The MCAFV, eCPP,ZFP, CO₂R, and cerebral autoregulation were assessed beforeand after SGB using established TCD methods. The changes inthese variables were analysed using Wilcoxon's signed rank test. Results. The block caused a significant decrease in MCAFV frommedian (inter-quartile range) value of 61 (53, 67) to 55 (46,60) cm s^–1, a significant increase in eCPP from 59 (51,67) to 70 (60, 78) mm Hg, and a significant decrease in ZFPfrom 32 (26, 39) to 25 (16, 30) mm Hg. There were no significantchanges in CO₂R or cerebral autoregulation. Conclusion. The increase in eCPP, decrease in ZFP, and no changesin CO₂R or cerebral autoregulation suggest that the SGB decreasescerebral vascular tone without affecting the capacity of thevessels to autoregulate. These effects may be of therapeuticadvantage in relieving cerebral vasospasm in certain clinicalsettings.     

Anoxic depolarization of rat hippocampal slices is prevented by thiopental but not by propofol or isoflurane

Background. There is strong evidence to suggest that anoxicdepolarization (AD) is an important factor in hypoxia/ischaemia-inducedneural damage. Treatments that prevent the occurrence of ADmay be useful in providing neuronal protection against hypoxia.The current study was designed to determine whether generalanaesthetics which have been suggested to ‘induce prophylaxis’against hypoxia can attenuate the incidence of AD. Methods. The effects of anoxia (3 min) on evoked extracellularlyrecorded field potentials of CA1 neurons in rat hippocampalslices were assessed in the absence and presence of the i.v.general anaesthetics thiopental and propofol and the volatileanaesthetic isoflurane. Results. In the absence of anaesthetics, AD occurred in 81%of the preparations tested. Thiopental (2x10^–4 M) significantlyreduced the incidence of AD (16%, P=0.0006). In comparison,propofol (2x10^–4 M) and isoflurane (1.5 vol%) were ineffective(69% and 60%, respectively). Furthermore, in the presence ofthiopental, the population spike amplitude recovered with andwithout AD (90% and 94% of pre-anoxic value, respectively) following3 min anoxia. Conclusion. The prophylactic effect of thiopental against hypoxiamight be induced, in part, by preventing the generation of AD.