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S J Verhulst

Publications and source records attributed to S J Verhulst.

18 recordsLinked to original sources
PubMed1992

Six years of comprehensive, clinical, performance-based assessment using standardized patients at the Southern Illinois University School of Medicine.

By the end of 1990-91, the Southern Illinois University School of Medicine had had six years of experience with comprehensive, performance-based examinations of senior medical students' levels of clinical competence; this report assesses the psychometric aspects of the six examinations given during that period. The examinations were aimed at determining the students' readiness for postgraduate training. Compared with other clinical performance-based assessments that use standardized patients (SPs), these examinations had two important and unique features: (1) the examinations assessed a comprehensive range of clinical skills and reasoning; and (2) they approximated the challenges of real clinical practice wherein a practitioner's skills need to be orchestrated and prioritized in order to meet the challenges of the case encountered. Each year, the performance-based assessment given was an intensive clinical examination requiring each student to work up 13 to 18 SP problems over a three-day period. To administer an examination to an entire class of students took three weeks. Because all students after the first year of administration (1986) were required to pass these examinations, the fairness of test design and scoring and the setting of performance standards for the examinations became important issues for the faculty. The results, accumulated over six years and based on a total of 6,804 student-patient encounters involving 405 students, indicate that this kind of clinical performance-based examination can discriminate a wide range of students' clinical performances. The results provide evidence for the examinations' test security, content validity, construct validity, and reliability.

Clinical Clerkship↗
PubMed1992

Standardized (simulated) patients' accuracy in recording clinical performance check-list items.

In large-scale performance-based assessment of medical professionals' clinical competence, simulated patients (standardized patients-SPs) are used not only to simulate case problems but also to record on check-list the examinees' clinical performance during their encounter with the SPs. The purposes of this study were to determine the SPs' overall accuracy in recording check-list items, and whether their accuracy was affected by the various characteristics of the check-list, and by the different times during a day and the different days within the examination when the recordings were obtained. Results showed that the SPs' accuracy in recording check-list items was good to very good and was affected by the length of the check-list, as well as by the type and the clarity of the check-list item. It was further found that the SPs' accuracy was consistent and did not vary over the course of a one-day or a 15-day examination.

Clinical Competence↗
PubMed1992

Influence of age on caloric expenditure during exercise.

Young (147 +/- 2 g) and adult (322 +/- 7 g) male Sprague Dawley rats were subjected to an incremental treadmill protocol and assessed via the Oxyscan Metabolic System in order to determine if differences exist relative to oxygen consumption (VO2, expressed in ml/kg/min), respiratory exchange ratio (RER) and caloric expenditure of two different age groups. The young rats attained a higher VO2 (81.55 +/- 1.22) compared to adult rats (68.97 +/- 2.05) at a maximal level of exercise. The adult rats became dependent upon carbohydrates as the primary source of energy until reaching 52% VO2 max, whereas the young rats did not resort to carbohydrate utilization as a primary fuel source until reaching 87% VO2max. At peak exercise, the adult animals burned only 15% less kcal/kg/h than the young rats, but the adult rats burned 37% more carbohydrate than the young animals. These data suggest that as exercise intensity increases, younger rats can more readily maintain a higher level of oxygen consumption accompanied by a more efficient use of fat as an energy source compared to adult rats. The clinical implication of this finding suggests that during the growth and development years of life, fat plays a significant role in energy expenditure needs and may therefore be more important than currently believed in young children's nutritional intake.

Aging↗
PubMed1991

Effect of pregnancy on glucose metabolism in glucose intolerant 'BB' Wistar rats.

Little is known about the effect of pregnancy on the 'BB' Wistar rat, an animal model of insulin-dependent (type I) diabetes. The pathogenesis of diabetes in this animal model seems to result from antibody-mediated natural killer cell destruction of pancreatic beta cells. The glucose metabolism of glucose intolerant female rats (study group) was studied prior to pregnancy, during pregnancy, and postpartum using glucose tolerance tests (GTT). Control rats with normal GTT were studied and bred in a fashion similar to the study animals. Before becoming pregnant, the GTT levels of the chemically diabetic rats were significantly different from those of the controls (p less than 0.05). The GTT values of the study animals decreased during pregnancy to levels seen in pregnant controls. After pregnancy, the GTT values of the study animals returned to prepregnant levels. Based on these observations, it appears that pregnancy may block the autoimmune destruction of beta cells, causing an increase in insulin production and release, thereby improving glucose metabolism.

Animals↗
PubMed1991

Test security in examinations that use standardized-patient cases at one medical school.

The use of performance-based examinations consisting of standardized-patient (SP) cases has increased greatly in recent years. These examinations are typically long and thus require the presentation of the same SP cases to several consecutive examinee groups. Consequently, concerns have arisen about the potential for violations of test security whereby students who were tested early in the examination period pass on information to students tested later. These concerns are addressed using data from the SP-based examinations administered to five classes (1986-1990) of senior medical students at Southern Illinois University School of Medicine. Because of the length of the examinations, each class was randomly divided into five groups and the examination was administered to one group at a time, requiring three days of testing time per group and three weeks of testing time per class. The results showed no consistent, systematic changes in case means across the five groups tested at different times throughout the examination period, and thus provide no evidence of serious, widespread violations of test security.

Education, Medical↗
PubMed1991

Reliability and efficiency of components of clinical competence assessed with five performance-based examinations using standardized patients.

The present study was conducted to provide in-depth information on the reliabilities of measures of the separate components of clinical competence (e.g. data collection, test interpretation, diagnosis, etc.) assessed by a performance-based examination consisting of standardized-patient cases administered to five classes of senior medical students at Southern Illinois University School of Medicine. In general, the reliabilities of the competencies as they were actually measured on the examination (using the number of cases on which each competency was actually measured) were small, with 54% less than 0.30 and 75% less than 0.40. For generalizability coefficients pooled across the five classes and projected to a common number of k = 10 cases, two of the nine competencies had reliabilities in the 40s, a third was close to 0.40, and the remaining six were in the low 20s. The number of cases needed for the competencies to achieve the recommended reliability of 0.80 ranged from 45 to 170 cases, with six of the nine competencies requiring over 100 cases to reach the 0.80 level. The low reliabilities of these measures of the components of clinical competence raise serious questions about using the scores as indicators of student performance.

Clinical Clerkship↗
PubMed1991

Data analysis techniques in behavioral pediatrics: some practical advice.

A review of the last three volumes of the Journal of Developmental and Behavioral Pediatrics revealed that 27% of the articles used correlations, 17% chi 2, 16% t tests, 15% analysis of variance or covariance, and 13% involved regression analysis. Multivariate techniques, discriminant or factor analysis, logistic regression, and sensitivity/specificity were used in less than 5% of articles; the average number of statistical techniques per article was 2.5. These statistical techniques are described in general, conceptual terms in regard to appropriate and inappropriate usage. Clinical examples are provided. Familiarity with these techniques allows the reader "statistical access" to almost 90% of the articles in behavioral pediatrics and other areas of the medical literature.

Child↗
PubMed1990

Measurement of gastric emptying rate in humans. Simplified scanning method.

Simultaneous measurements of the gastric emptying rate of the solid and liquid phase of a dual-isotope-labeled test meal were made using a gamma camera and a simple scintillation detector, similar to that used in a hand-held probe. A simple scanning apparatus, similar to that used in a hand-held scintillation probe, was compared with simultaneous measurements made by a gamma camera in 16 healthy males. A dual-labeled test meal was utilized to measure liquid and solid emptying simultaneously. Anterior and posterior scans were taken at intervals up to 120 min using both a gamma camera and the scintillation probe. Good relative agreement between the methods was obtained both for solid-phase (correlation range 0.92-0.99, mean 0.97) and for liquid-phase data (correlation range 0.93-0.99, mean 0.97). For solid emptying data regression line slopes varied from 0.75 to 1.03 (mean 0.84). Liquid emptying data indicated that slopes ranged from 0.71 to 1.06 (mean 0.87). These results suggested that an estimate of the gamma measurement could be obtained by multiplying the scintillation measurement by a factor of 0.84 for the solid phase and 0.87 for the liquid phase. Correlation between repeat studies was 0.97 and 0.96 for solids and liquids, respectively. The application of a hand-held probe technique provides a noninvasive and inexpensive method for accurately assessing solid- and liquid-phase gastric emptying from the human stomach that correlates well with the use of a gamma camera, within the range of gastric emptying rate in the normal individuals in this study.

Adult↗
PubMed1989

Outcome studies of low birth weight infants published in the last decade: a metaanalysis.

We conducted a metaanalysis and methods review of 80 studies, published in the last decade, that explored the outcome of low birth weight infants; 27% involved infants whose birth weights were less than or equal to 2500 gm (low birth weight), 44% less than or equal to 1500 gm (very low birth weight), and 29% less than or equal to 1000 gm (extremely low birth weight). Problems found in these studies were grouped into three categories: subject and methods issues, environmental factors, and outcome measurement. The combined average intelligence quotient/developmental quotient (IQ/DQ) of all low birth weight groups was 97.77 (SD 6.19); for control subjects the mean IQ/DQ was 103.78 (SD 8.16). This difference was statistically significant but perhaps not clinically significant. No differences in mean IQ/DQ scores were found among the low birth weight, very low birth weight, and extremely low birth weight subgroups. Statistically significant differences among all groups and control subjects were found when categoric data were analyzed, as were differences among the three subgroups; however, the variety of outcome criteria makes interpretation of the categoric analyses difficult.

Environment↗
PubMed1989

Using a standardized-patient examination to establish the predictive validity of the MCAT and undergraduate GPA as admissions criteria.

Performance of senior medical students on an objectively scored examination of clinical competence based on standardized-patient cases was used to assess the predictive validity of the two most commonly used admission measures, the Medical College Admissions Test and the undergraduate grade point average. The students were in the classes of 1986 and 1987 at Southern Illinois University School of Medicine. The correlations of the admissions measures with clinical performances were quite weak, and none of the admissions measures consistently showed a clear advantage as a predictor of clinical performance. Correlations of the admissions measures with scores on National Board of Medical Examiners (NBME) Part I and Part II examinations were small to moderate, although somewhat larger than the correlations with clinical performances. Correlations were corrected for attenuation due to differential unreliabilities of the clinical examination results and the scores on NBME examinations, and for restriction of range due to the stringent medical school selection process. Corrected correlations were small to moderate and showed the same pattern as the uncorrected ones. The study documents that traditional admissions measures are useful for selecting students who will perform effectively in clinical as well as basic science settings.

Clinical Competence↗
PubMed1989

Correlation of asphyxia and other risk factors with outcome: a contemporary view.

The relationships between 14 maternal/prenatal, 24 perinatal and 12 asphyxia-related variables and outcome at 40 weeks, nine, 18 and 36 months were evaluated in a sample of 608 children enrolled in the multi-center National Heart, Lung and Blood Institute Collaborative study. Correlations were weak generally, although they tended to be stronger for perinatal variables and neurological outcome at 36 months. When the maternal/prenatal and perinatal variables (medical/biological), the SES-Composite Index (environmental/psychosocial) and the Early Neuropsychologic Optimality Rating Scale-9 (behavioral/developmental) were used as optimality scales, prediction was enhanced; however, it appeared that the environmental/psychosocial and behavioral/developmental scales were more predictive of 36-month outcome than were medical/biological variable groupings.

Aging↗
PubMed1988

The use of performance-based assessment scores and traditional measures in predicting first-year residency performance.

The purpose of this study is to examine the relationship between students' performance on a performance-based clinical examination and their subsequent performance during the first year of residency. Additionally, its purpose is to further examine the relationship between the performance-based clinical examination and existing measures of clinical competence (clerkship ratings, and NBME Part I and II scores).

Clinical Clerkship↗
PubMed1988

The Early Neuropsychologic Optimality Rating Scale (ENORS-9): a new developmental follow-up technique.

The development and application of the Early Neuropsychologic Optimality Rating Scale (ENORS-9) is described. This 24-item technique, scored in an optimal/nonoptimal fashion, enables assessment of posture, tone, and movement, as well as developmental delays. The ENORS-9 was compared with the Bayley Mental and Psychomotor Developmental indexes and a neurologic examination administered at 9 months, in terms of sensitivity and specificity of cognitive, motor, and neurologic outcome at 36 months. Using an ENORS-9 cut-off score of 85% for cognitive and motor, and 75% for neurologic outcome, sensitivity values were more than three times greater than more traditional assessment techniques. This instrument meets many needs in developmental follow-up because of straightforward scoring, decreased personnel requirements and cost, and flexibility in regard to missing data and cut-off scores. The implications of these findings are discussed.

Child Development↗
PubMed1987

Direct, standardized assessment of clinical competence.

Doctor ratings of clerkship performance are often discounted as not accurately reflecting clinical competence. Such ratings are influenced by the following uncontrolled variables: case difficulty; differing rater focus and standards; lack of agreement on what constitutes acceptable performance; and collective patient care responsibility masks individual contributions. Standardized direct measures of clinical competence were developed to control these factors and allow direct comparisons of student performance. Students saw 18 patients representing frequently occurring and important patient problems. Student actions and decisions were recorded and subsequent responses to questions revealed knowledge of pathophysiology, basis for actions, use and interpretation of laboratory investigations, and management. Actions and responses were graded using a pre-set key. The examination covered 73% of designated clinical competencies. Examinations scores corresponded with independent measures of clinical competence. Reliability studies indicated that new cases can be substituted in subsequent years with confidence that scores will maintain similar meaning. Costs are +6.95 per student per case, which is modest considering the quality and quantity of information acquired. Methods described are practical for evaluation of clerks and residents and for licensing and specialty certification examinations.

Clinical Clerkship↗