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J A Colliver

Publications and source records attributed to J A Colliver.

At least 19 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

Screening test length for sequential testing with a standardized-patient examination: a receiver operating characteristic (ROC) analysis.

The feasibility of using sequential testing (i.e., using a screening test) to reduce the length and expense of a performance-based examination with standardized-patient cases was demonstrated previously. In the present study, quantitative criteria rather than practical considerations were used to determine optimal values for the length of the screening test (i.e., number of cases) and the location of the screening pass-fail cutoff (i.e., its relation to the mean of the pass levels for the different cases). Data were derived from five classes of senior students at the Southern Illinois University School of Medicine, 1987-1991. Specifically, receiver operating characteristic (ROC) curves were plotted for screening tests of varying lengths, with the points on each ROC curve corresponding to different pass-fail cutoffs on the screening test. The results showed that good accuracy can be attained with a screening test that is only one-third the length of the full examination and that the cutoff for this screen should be set slightly above the mean of the case pass levels to maximize sensitivity and specificity. The authors conclude that their study demonstrates the value of an ROC analysis in evaluating the psychometric properties of a screening test in sequential testing.

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↗
PubMed1991

Stability of peripheral hematological parameters after chronic acetylcholinesterase inhibition in man.

Acetylcholinesterase (AChE; EC 3.1.1.7) is present in both primitive and mature erythroid cells, and a role has been suggested for the enzyme in regulation of differentiation in the human erythron. AChE is also a major enzyme in the central nervous system; alteration of its activity has been proposed as a therapeutic strategy in Alzheimer disease. We recently treated 18 Alzheimer disease patients with metrifonate, a long-acting AChE inhibitor, over periods up to 7 months, with resulting erythrocyte AChE inhibition as high as 82 per cent of baseline values. Despite chronic reduction of enzyme activity, no significant alterations were noted in erythrocyte, leukocyte or platelet characteristics or numbers that would suggest a deleterious effect of AChE inhibition on normal differentiation. Thus, any modification of developmental pathways appears to be compensated by other regulatory mechanisms in the intact organism.

Alzheimer Disease↗
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

Effects of using two or more standardized patients to simulate the same case on case means and case failure rates.

The effects of using two or more standardized patients (multiple SPs) to simulate the same case in a performance-based examination were studied at the case level by comparing case means and case failure rates for multiple SPs simulating the same case, using data from the classes of 1988, 1989, and 1990 at the Southern Illinois University School of Medicine. For total scores and scores on the students' written answers, the effects on means and failure rates were negligible and could be explained as due to sampling error. For scores on the checklists completed by the SPs, there were more significant differences than would be expected by chance alone, even though the number of significant differences was relatively small. The results demonstrate a need for caution in the interpretation of scores obtained from a case checklist completed by multiple SPs, particularly in regard to making pass-fail decisions.

Achievement↗
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↗
PubMed1990

Cerebrospinal fluid choline levels are decreased in Parkinson's disease.

We examined acetylcholinsterase (AChE) activity and choline levels in cerebrospinal fluid (CSF) in 16 patients with idiopathic Parkinson's disease and 9 control subjects of corresponding age: 8 were untreated Parkinson's patients; 4 were treated with carbidopa-levodopa (100/1,000 mg/day) for 20 +/- 3 months; and 4 were treated with carbidopa-levodopa (110/1,100 mg/day) for 28 +/- 18 months plus amantadine (200 mg/day) for 16 +/- 8 months. CSF choline levels (nmol/ml) were 2.97 +/- 0.79 (control subjects); 1.31 +/- 0.29 (untreated patients); 1.00 +/- 0.29 (carbidopa-levodopa treated); and 1.26 +/- 0.19 (carbidopa-levodopa/amantadine treated). Choline levels were significantly lower in untreated and treated patients compared to control subjects (p = 0.0001). AChE activity did not differ in Parkinson's disease patients as compared to control subjects. The reduced level of choline in CSF may reflect a deficit in choline transport into the brain or a decrease of choline-phospholipid output from the brain.

Acetylcholinesterase↗
PubMed1990

Cerebrospinal fluid acetylcholinesterase and choline measurements in Huntington's disease.

The caudate nucleus has the highest acetylcholinesterase (AChE) activity in the brain and it has been shown that autopsied brain tissue of patients with Huntington's disease (HD) have reduced levels of acetylcholine. Because of these findings, the cholinergic function in HD was studied by measuring cerebrospinal fluid (CSF) choline levels and AChE activity during a randomized, double-blind, cross-over, placebo-controlled clinical trial of isoniazid. While mean choline levels adjusted for age were lower compared with controls (P = 0.0007), AChE activity did not differ between HD patients and normal controls. Treatment with isoniazid had no significant effect on CSF choline levels or CSF AChE activity. CSF AChE activity showed a statistically significant increase with advancing age. The reduced level of choline in CSF of HD patients may reflect either a defect in choline transport into the brain or a decrease of choline-phospholipid output from the brain.

Acetylcholinesterase↗
PubMed1990

Reassessment of body mass indices.

The accuracy of body mass indices (BMIs), such as Quetelet's index, for the definition of obesity was investigated in a large sample of healthy humans. Two hundred thirteen women and 150 men with a wide spectrum of weights, heights, and ages underwent densitometric analysis for the determination of percent body fat (%BF). %BF was then contrasted with various well-established BMIs. Although %BF was correlated with all the BMIs (r = 0.60-0.82), applying objective definitions of obesity based on BMIs or %BF by densitometry often produced conflicting results. It was also found that the 95% confidence intervals for predicting %BF by using Quetelet's index were very wide. Because of the wide variation for individuals between densitometrically determined body fat and body fat as estimated by BMIs, we conclude that BMIs should be used with caution as indicators of obesity.

Adipose Tissue↗
PubMed1990

The effects of various anesthetics on tissue levels of fructose-2,6-bisphosphate in rats.

We report that the short-term use of various anesthetic agents prior to decapitation causes alteration of the levels of fructose-2,6-bisphosphate in kidney, brain, heart, muscle, and liver. These data indicate that even light anesthesia can not be used when levels of this metabolite are to be determined. Also, it appears that the use of any of these anesthetics can profoundly alter glucose utilization in many tissues.

Anesthetics↗
PubMed1990

Sperm washing and intrauterine insemination for cervical factor, oligospermia, immunologic infertility and unexplained infertility.

The cumulative pregnancy rate was evaluated for 56 couples undergoing 227 intrauterine inseminations (IUIs) after sperm washing. The indications for IUI were cervical factor, oligospermia, immunologic infertility and unexplained infertility. The overall pregnancy rate was 21.4%, with a 0.289 cumulative probability of conception after six cycles. Within each category the pregnancy rates were 25% for cervical factor, 60% for women with antisperm antibodies, 20% for men with antisperm antibodies and 7% for oligospermia.

Clinical Trials as Topic↗