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PubMed1994

Uncertainties and ambiguities: measuring how medical students cope.

To develop psychometric measures specific to the ambiguities encountered in medicine and determine their value in predicting medical students' attitudes towards patients and their choice of residency, we administered to senior and first-year medical students a 25-item Likert-type questionnaire to assess their intolerance of ambiguity (ITA). Factor analysis yielded two dimensions that were converted to scales: 'Aversion to uncertainties in clinical medicine' (ITA1) and 'Preference for highly structured training environs' (ITA2). First-year students scored higher on ITA1 and lower on ITA2 than seniors. An excessive reliance on high-technology medicine, a negative orientation toward psychological problems, and Machiavellianism predicted ITA1. ITA1 was the best predictor of senior medical students' negative attributional style toward hypochondriac, geriatric and chronic pain patients. The following rank order of seniors' career choice was predicted by ITA1 scores: internal medicine, psychiatry and family medicine (lowest); radiology, surgery and anaesthesiology (highest). And by ITA2 scores: surgery, obstetrics and gynaecology, and surgical subspecialties (lowest); radiology, psychiatry and anaesthesiology (highest). We concluded that personality traits and role characteristics which predict 'Aversion to uncertainties in clinical medicine' are maladaptive to managing many primary care patients, and this mismatch is reflected in seniors' residency choice.

Adaptation, Psychological↗

PubMed1990

The principle of parsimony: Glasgow Coma Scale score predicts mortality as well as the APACHE II score for stroke patients.

Although the development and use of severity-of-illness measures has gained widespread enthusiasm, uncertainty remains as to the optimal measure for stroke patients. The Health Care Financing Administration recently derived a severity-of-illness measure based on the APACHE II system to explain differences in Medicare mortality rates among hospitals treating stroke patients. We hypothesized that the Glasgow Coma Scale score provides prognostic information of accuracy comparable to that of the APACHE II score for stroke patients, yet is simpler and cheaper to abstract from the medical record. We therefore studied 246 patients hospitalized with stroke, including 49 oversampled mortalities. The Glasgow Coma Scale score was as accurate as the APACHE II score in predicting stroke mortality both before (r = -0.50 and r = 0.50, respectively) and after (r = -0.40 and r = 0.38, respectively) the oversampled mortalities were excluded. The APACHE II score required abstraction of 16 variables from the medical record compared with three for the Glasgow Coma Scale score and required more than three times the time to abstract from the medical record. Therefore, in the interest of parsimonious data collection, the Glasgow Coma Scale may be a preferable severity-of-illness measure for patients with stroke.

Aged↗

PubMed2006

Genome-wide linkage scan for spontaneous DZ twinning.

In humans, spontaneous DZ twinning is known to have a genetic basis. A prior investigation in the Flemish and Dutch population showed that the phenotype of 'having DZ twins' was consistent with an autosomal monogenic dominant model, with a gene frequency of 3.5% and a female-specific lifetime penetrance of 10%. Recessive, X-linked, polygenic and sporadic models were rejected. This study reports on a genome-wide scan of 14 Flemish families containing 57 mothers of spontaneous DZ twins. Two-point linkage analysis using the autosomal dominant model showed nine chromosomal regions with a LOD score around 1. After multipoint linkage analysis, including heterogeneity, three chromosomes continued to give high LOD scores. These regions were further haplotyped with additional markers at 1 cM distance. The multipoint analysis was not in favour of linkage of the DZ twinning trait in most candidate genes and other regions (LOD score < -2) under the genetic model of autosomal dominance. To further evaluate the evidence for linkage given some uncertainty about the correct mode of inheritance of twinning susceptibility other models of inheritance were tested. Results of this analysis showed all models gave highest LOD scores under dominant models. If heterogeneity among the families is taken into account, the peaks that were observed on chromosome 2, 7 and 18 could well contain a potential gene contributing to DZ twinning. These results give suggestive evidence that the mode of inheritance of DZ twinning is probably more complex than was originally expected.

Belgium↗

PubMed2002

History by history statistical estimators in the BEAM code system.

A history by history method for estimating uncertainties has been implemented in the BEAMnrc and DOSXYznrc codes replacing the method of statistical batches. This method groups scored quantities (e.g., dose) by primary history. When phase-space sources are used, this method groups incident particles according to the primary histories that generated them. This necessitated adding markers (negative energy) to phase-space files to indicate the first particle generated by a new primary history. The new method greatly reduces the uncertainty in the uncertainty estimate. The new method eliminates one dimension (which kept the results for each batch) from all scoring arrays, resulting in memory requirement being decreased by a factor of 2. Correlations between particles in phase-space sources are taken into account. The only correlations with any significant impact on uncertainty are those introduced by particle recycling. Failure to account for these correlations can result in a significant underestimate of the uncertainty. The previous method of accounting for correlations due to recycling by placing all recycled particles in the same batch did work. Neither the new method nor the batch method take into account correlations between incident particles when a phase-space source is restarted so one must avoid restarts.

Biophysical Phenomena↗

PubMed2002

BALSA: Bayesian algorithm for local sequence alignment.

The Smith-Waterman algorithm yields a single alignment, which, albeit optimal, can be strongly affected by the choice of the scoring matrix and the gap penalties. Additionally, the scores obtained are dependent upon the lengths of the aligned sequences, requiring a post-analysis conversion. To overcome some of these shortcomings, we developed a Bayesian algorithm for local sequence alignment (BALSA), that takes into account the uncertainty associated with all unknown variables by incorporating in its forward sums a series of scoring matrices, gap parameters and all possible alignments. The algorithm can return both the joint and the marginal optimal alignments, samples of alignments drawn from the posterior distribution and the posterior probabilities of gap penalties and scoring matrices. Furthermore, it automatically adjusts for variations in sequence lengths. BALSA was compared with SSEARCH, to date the best performing dynamic programming algorithm in the detection of structural neighbors. Using the SCOP databases PDB40D-B and PDB90D-B, BALSA detected 19.8 and 41.3% of remote homologs whereas SSEARCH detected 18.4 and 38% at an error rate of 1% errors per query over the databases, respectively.

Algorithms↗

PubMed2005

Assessment of validity for EuroSCORE risk stratification system.

UNLABELLED: Prognostic scoring helps doctors, patients and their families to weigh the risks and benefits of medical care and clarifies their expectations. OBJECTIVE: We aimed to analyze the risk stratification performance of the EuroSCORE system because of its common use in Lithuania. DESIGN: EuroSCORE performance is assessed in terms of sensitivity, specificity, accuracy and area under the receiver operating characteristic (ROC) curve (AUC). Logistic regression is carried out for modeling categorical data and odds ratio calculations of being a non-survivor case for each EuroSCORE risk group. RESULTS: The study was completed on 1002 patients. Mean score for EuroSCORE was 4.77 +/- 2.8; ROC curve of 0.71; accuracy was 65.5%; 65.4% sensitivity and 67.2% specificity. CONCLUSIONS: EuroSCORE created a moderately predictive area under the ROC curve for our patient population. Probability of non-survival by logistic regression model for each EuroSCORE risk group is statistically significantly higher compared to the lower risk group. Predictions available from prognostic scoring systems could be useful in decision making when there is uncertainty in whether to carry out surgery or not.

Aged↗

PubMed1990

The impact of phenotypic variation on genetic analysis: application to X-linkage in manic-depressive illness.

Genetic linkage studies have opened new vistas for behavioral and psychiatric genetics. However, phenotypic diversity and diagnostic uncertainties can lead to spurious linkage findings. A method of analysis is proposed that takes these factors into account. When applied to manic-depressive disease, the results indicate that previous evidence for a major gene localized on the distal long arm of the X-chromosome cannot be ascribed to phenotypic uncertainties and misclassifications, i.e., a type I error. Although the lod score (the logarithm of odds) favoring linkage is reduced with the more restrictive clinical definitions of the phenotype, it remains significant nonetheless. Thus, the linkage finding is robust over a range of phenotypic patterns and presumed phenocopy frequencies. The results also suggest that the X-linked phenotype is a particularly severe form of manic depression characterized by early onset, high familial prevalence of the bipolar form, and high recurrence rate of major depression. These findings may have important implications for the design and interpretation of genetic linkage studies and for refining diagnostic techniques in mental disorders.

Adolescent↗

PubMedDate not supplied

Role and gender differences in cancer-related distress: a comparison of survivor and caregiver self-reports.

PURPOSE/OBJECTIVES: To examine role and gender differences on measures of psychological distress as a consequence of dealing with cancer. DESIGN: Cross-sectional, descriptive, quantitative analyses of retrospective survey data. SETTING: A large, nonprofit, volunteer-based cancer organization. The sample was recruited through an online cancer survivor's network (61%), a rural event (24%), and hospital registries (15%). SAMPLE: Convenience sample of 135 cancer survivors matched to their family caregivers (N = 270). METHODS: Dyads (i.e., survivors and family caregivers) completed matched questionnaires requesting demographic and medical information and measures of cancer-related distress. MAIN RESEARCH VARIABLES: Role (i.e., survivor or caregiver), gender, and psychological distress. FINDINGS: Caregiver means on overall psychological distress were significantly higher than those shown for survivors. Caregiver scores were significantly higher on distress for diagnosis and fear of cancer recurrence. Females scored higher than male caregivers on cancer-related anxiety, future uncertainties, fear of recurrence, and future diagnostic tests. Gender differences were not found for survivor distress. CONCLUSIONS: Results suggest a need for gender-specific, dyad-tailored cancer support services. IMPLICATIONS FOR NURSING: As expert caregivers, nurses can provide valuable assistance with the caregiving process that may decrease distress during the family's cancer experience and adaptation period.

Adaptation, Psychological↗

PubMed2005

The injury scale--a valuable tool for forensic documentation of trauma.

An accurate method for quantitatively summarizing injury severity has many potential applications. The ability to predict outcome from trauma (i.e., mortality) is perhaps the most fundamental use of injury severity scoring, a use that arises from the patient's and the family's desires to know the prognosis. Field trauma scoring also is used to facilitate rational pre-hospital triage decisions, thereby minimizing the time from injury occurrence to definitive management. Another use of trauma scoring is for quality assurance by allowing evaluation of trauma care both within and between trauma centers, a contentious and controversial area that is likely to only increase in importance. However, the most important role for injury severity scoring is in trauma care research. Scientific study of the epidemiology of trauma and trauma outcomes would not be possible otherwise. Injury severity scoring is indispensable in stratifying patients into comparable groups for prospective clinical trials. Similarly, this technique can be used retrospectively to identify and control for differences in baseline injury severity between patient populations. More recently, physicians suggested that injury severity scoring could provide objective information for end-of-life decision-making and resource allocation. Unfortunately, trauma mortality prediction in the individual patient is limited and fraught with uncertainty. In fact, decisions for individual patients should never be based solely on a statistically derived injury severity score.

APACHE↗

PubMed2001

Inter-organisational sampling trials for the uncertainty estimation of landfill gas measurements.

Inter-organisational sampling trials were performed at a reclaimed landfill site in Bedfont, West London, UK, to assess the uncertainty in measured concentrations of landfill gas. Eight participants independently measured concentrations of methane, carbon dioxide and oxygen, each on one occasion, over a two week period in February 1999. The organisers monitored the natural variability of the gas concentration over this sampling period using a control borehole in order to separate the variance that arose as a result of the sampling procedure from that caused by natural geochemical variation. A collaborative trial in sampling showed the extent of agreement between participants' results when they measured gases using the same, nominal protocol and equipment. The protocol was identified as fit for the purpose of estimating the mean concentration of methane, carbon dioxide and oxygen in a single borehole to within 21%, 15% and 321% of their assigned values, respectively (at 95% confidence). A realistic estimate of uncertainty in measurements of concentration from different protocols was estimated by the use of a sampling proficiency test, in which participants collected measurements using a protocol selected on the basis of their own professional judgement. Each participant's performance was compared with the consensus mean for each of the three gases using the z-score assessment proposed by the International Harmonised Protocol. This test highlighted the potentially large uncertainty in measured gas concentrations that can arise (91% relative uncertainty for CH4 in one borehole), and identified that an improved sampling protocol is required if misclassification of the explosive potential of methane is to be avoided.

Air Pollution↗

PubMed2000

Reward discounting as a measure of impulsive behavior in a psychiatric outpatient population.

Impulsivity has been operationalized as a choice of an immediate smaller reward over a larger delayed or uncertain reward. This study examined a procedure that measures reward preference under these contingencies in psychiatric outpatients considered either at a high or low risk for engaging in impulsive behavior depending on their psychiatric diagnoses. The participants' rates of delay and uncertainty reward discounting were compared with their performances on a behavioral inhibition task and responses on a self-report personality impulsivity measure. The high-risk participants discounted delayed rewards more sharply and scored higher on the self-report impulsivity measure relative to the low-risk participants. Delay and uncertainty discounting were modestly correlated, but no other relationships were found between the other measures. Results from this study indicate that delay-discounting tasks may be sensitive to at least one form of impulsive behavior.

Adult↗

PubMed1995

Studying the effect of clinical uncertainty on physicians' decision-making using ILIAD.

The influence of uncertainty on physicians' practice behavior is not well understood. In this research, ILIAD, a diagnostic expert system, has been used to study physicians' responses to uncertainty and how their responses affected clinical performance. The simulation mode of ILIAD was used to standardize the presentation and scoring of two cases to 46 residents in emergency medicine, internal medicine, family practice and transitional medicine at Methodist Hospital of Indiana. A questionnaire was used to collect additional data on how physicians respond to clinical uncertainty. A structural equation model was developed, estimated, and tested. The results indicate that stress that physicians experience in dealing with clinical uncertainty has a negative effect on their clinical performance. Moreover, the way that physicians respond to uncertainty has positive and negative effects on their performance. Open discussions with patients about clinical decisions and the use of practice guidelines improves performance. However, when the physician's clinical decisions are influenced by patient demands or their peers, their performance scores decline.

Clinical Competence↗

PubMed1995

Triage decisions for emergency department patients with chest pain: do physicians' risk attitudes make the difference?

OBJECTIVE: To determine whether physicians' risk attitudes correlate with their triage decisions for emergency department patients with acute chest pain. DESIGN: Cohort. SETTING: The emergency department of a university teaching hospital. PATIENTS: Patients presenting to the emergency department with a chief complaint of acute chest pain. PHYSICIANS: All physicians who were primarily responsible for the emergency department triage of at least one patient with acute chest pain from July 1990 to July 1991. METHODS: The physicians' risk attitudes were assessed by two methods: 1) a new, six-question risk-taking scale adapted from the Jackson Personality Index (JPI), and 2) the Stress from Uncertainty Scale (SUS). RESULTS: The physicians who had high risk-taking scores ("risk seekers") admitted only 31% of the patients they evaluated, compared with admission rates of 44% for the medium scores and 53% for the physicians who had low risk-taking scores ("risk avoiders"), p < 0.001. After adjustment for clinical factors, the patients triaged by the risk-seeking physicians had half the odds of admission [odds ratio (OR) 0.51, 95% confidence interval (95% CI) 0.27 to 0.97], and the patients triaged by the risk-avoiding physicians had nearly twice the odds of admission (OR 1.83, 95% CI 1.10 to 3.03) of the patients triaged by the medium-risk scoring physicians. The SUS did not correlate significantly with admission rates. Of the 92 patients released home by the risk-seeking physicians, 91 (99%) were known to be alive four to six weeks afterwards and one was lost to follow-up; among the 66 patients released by the risk-avoiding physicians, 64 (97%) were known to be alive at four to six weeks, one was lost to follow-up, and one died of ischemic heart disease during a subsequent hospitalization (p = NS). CONCLUSIONS: The physicians' risk attitudes as measured by a brief risk-taking scale correlated significantly with their rates of admission for emergency department patients with acute chest pain. These data do not suggest that the risk-seeking physicians achieved lower admission rates by releasing more patients who needed to be in the hospital, but an adequate evaluation of the appropriateness of triage decisions of risk-seeking and risk-avoiding physicians will require further study.

Acute Disease↗

PubMed1999

Cytogenetic analysis of peripheral blood lymphocytes of occupational workers exposed to low levels of ionising radiation.

The incidence of chromosomal aberrations was analysed in peripheral blood lymphocytes of occupationally exposed people having cumulative doses of 500 mSv. The exposed individuals showed higher frequencies of dicentrics as well as acentrics than normal controls. Absorbed radiation dose was calculated by using in vitro dose response curve established for Cobalt-60 gamma rays. In the control constituting 17 healthy individuals, two dicentrics were detected among 3700 metaphases analysed. In the exposed group 27 dicentrics and one centric ring was detected among 8400 metaphases analysed. Due to small number of dicentrics scored in each individual, the dose estimate suffers from a large statistical uncertainty. The collective dose was found to be 1.89 Gy. This is in good agreement with the corrected physical doses, assuming a mean life of 10 years for the disappearance of lymphocytes. The physical doses accumulated during the last 10 years of occupation were also in good agreement with the biological dose estimate.

Adult↗

PubMed2005

An evaluation of raw milk microorganisms as markers of on-farm hygiene practices related to milking.

Dairy farm hygiene audits were undertaken at 24 farms during summer and winter and the results compared with transformed bacterial indicator levels in raw milk samples collected during each audit. The bacterial indicators measured were total viable counts, Escherichia coli, coliforms, Bacillus spp., Bifidobacteria spp., and Pseudomonas spp. The results of initial comparisons using Pearson product-moment correlation coefficients showed presumptive relationships between some bacterial groups and the subjective quantitative audit scores. When investigated further using linear regression, the presumptive relationships were found to be influenced by external factors. Possible reasons for the low correlations between on-farm hygiene and bacterial indicator counts in raw milk were further investigated. Measurements of the uncertainty associated with the bacteriological results were undertaken and revealed geometric relative standard deviations that ranged from 0.019 to 1.05. Toward the higher end of this scale, the uncertainty associated with the laboratory estimations of bacterial numbers may have been large enough to blur hygiene score-marker bacteria relationships. The samples obtained from on-farm raw milk storage tanks were representative of the whole tank contents and not a significant source of error. Although total bacterial counts are widely acknowledged by the milk industry as not always giving a true measure of on-farm hygiene during milking, we were unable to find any marker bacteria that showed consistently higher correlations and were thus better suited as indicators of on-farm hygiene.

Animal Husbandry↗

PubMed2005

Dysfunctional belief-based obsessive-compulsive disorder subgroups.

An attempt was made to identify obsessive-compulsive disorder (OCD) subgroups based on differences in OCD related beliefs. OCD patients (N=367) were assessed with the Obsessional-Beliefs Questionnaire prior to treatment. Individuals' scores on measures of inflated personal responsibility and the tendency to overestimate threat, perfectionism and intolerance of uncertainty, and over-importance and over-control of thoughts were subjected to cluster analysis. Support for both a simple and complex subgroup model was found (2-subgroup and 5-subgroup taxonomies). A low-beliefs subgroup was identified in both taxonomies. The low-beliefs subgroups reported scores on belief measures equivalent to scores reported for non-OCD comparison groups in earlier studies. Additional analyses were conducted to determine relations between belief-based and symptom subgroups. Significant relationships were found (e.g., Symmetry symptom subgroup membership was associated with membership in the Perfectionism/Certainty beliefs subgroup), although the shared variance was modest. Implications for understanding OCD heterogeneity and for cognitive theory are discussed.

Adult↗

PubMed2001

Photographic scoring of gingival overgrowth.

BACKGROUND: A wide range of methods have been employed to determine the severity of gingival overgrowth resulting in uncertainty regarding the prevalence of the side-effect. There is no simple, non-invasive, objective, blind method for assessing gingival overgrowth. AIM: This article aims to describe a method which is suitable for use in large-scale population studies. MATERIALS AND METHODS: Photographs were taken of the anterior, buccal gingivae and teeth of 925 patients medicated with calcium channel blockers. In addition, each patient was ascribed a clinical gingival overgrowth score. 100 patients had repeat photographs, and a further 10 patients had alginate impressions taken. The models were scored for severity of gingival overgrowth using a described technique. The slides were scored using a modification of this technique. RESULTS: When photographic and study model scores were compared, photographic scores were consistently higher, and as a result, a photographic score of 38.6% was considered to represent a significant overgrowth. There was good agreement between clinically determined scores and photographic scores (kappa=0.71). CONCLUSIONS: The results indicate that this method is suitable for large-scale population studies where it also has the advantage of providing a continuous scale of gingival changes for subsequent statistical analysis.

Calcium Channel Blockers↗

PubMed1998

African- and Euro-American samples differ little in scores on death anxiety.

Samples of 293 students of European heritage and 102 students of African heritage completed the Revised Death Anxiety Scale. Euro-Americans were more concerned with the uncertainty associated with death and with the loss of being, while African Americans expressed greater anxiety over the pain associated with dying, but there was no significant mean difference in total scores for the groups.

Adolescent↗