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Biomedical subjects

J A Colliver

Publications and source records attributed to J A Colliver.

At least 55 records · Page 3Linked to original sources
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↗
PubMed1989

Reliability of different grading systems used in evaluating surgical students.

Inter-rater agreement in assigning grades using five different grading systems was determined. The performance of 16 students in a surgery clerkship was rated by 21 faculty raters using a pass-fail grading system, a pass-fail-honors system, a letter grade system, a number grade scale from 1 to 10, and a number grade scale from 1 to 100. Inter-rater agreement coefficients were used to assess relative and absolute reliabilities, respectively. Both the letter grade and 1 to 10 number grade systems provided good discrimination, had high to moderate reliability, and required only five raters to achieve a mean rating with the commonly recommended reliability of 0.80. Using the letter grade system, however, a majority of raters agreed on a specific grade assignment for 14 of 16 students, in contrast to the 1 to 10 scale, for which this was true for only 4 of 16 students. The results of this reliability study favor the use of a letter grading system.

Clinical Clerkship↗
PubMed1989

Alzheimer patient evaluation and the mini-mental state: item characteristic curve analysis.

To develop a tool for precisely assessing dementia severity, items should be selected according to their relationship to the overall progression of the disease. Using an item characteristic curve analysis (ICC), items were examined from the Folstein Mini-Mental State Exam (MMSE), a useful clinical tool for evaluating dementia. MMSE data were available for 86 patients who met DSM-III criteria for primary degenerative dementia -- possible or probable Alzheimer's disease (AD). A logistic regression analysis of the probability of correct performance on an item, given the total MMSE score, yielded statistics for difficulty and discrimination. These statistics were interpreted respectively as indicators of the point in the progression of the illness at which the mental function tested by that item is lost and the rapidity of that loss. The data indicated a systematic progression of the development of symptoms in AD related to decline of memory function. Temporal orientation was lost before spatial and object orientation, and recollection of words was lost before ability to repeat them. ICC can help to delineate the loss of mental functions during the course of AD.

Aged↗
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↗