Uncertain Categories Research Articles

Abstract 258: Adherence To The AHA / ACCF / SCAI / ASE /ASNC - 2012 Appropriate Use Criteria For Diagnostic Cardiac Catheterization In An Academic Medical Center.

Objective: To examine the adherence to the published appropriate use criteria (AUC) for diagnostic cardiac catheterization (DCC) in an academic medical center. Background: In May 2012, the American Heart Association and other subspecialty societies have developed AUC for DCC to address the growing rational use of cardiac catheterization in delivering high quality health care. The application of all the subsets of AUC indications to examine the adherence of cardiologists in academic center has not been well studied. Methods: We retrospectively examined a random sample of 499 patients who underwent DCC in our institution between January 1, 2013 to June 30, 2013, seven months after the publication of AUC for DCC; and classified as appropriate, uncertain and inappropriate categories according to the AUC. Indications not addressed in the AUC were considered unclassified. Results: The mean age of the study population was 65 (± 13) years with 67% males. Distribution of DCC according to AUC is shown in Table-1. Most DCC were appropriate (93%; n= 462), 6% (n=31) were uncertain and none were inappropriate. Approximately 1% (n=6) DCC were unclassifiable and all had known obstructive coronary artery disease (CAD) with worsening or limiting symptoms without non invasive stress testing and did not meet criteria for unstable angina. About one quarter (22%; n= 21/86) of DCC performed for patients in the suspected CAD with or without prior non invasive stress testing group were uncertain, 78% (n= 65/86) were appropriate and none were inappropriate. Most DCC (92%) were performed by interventional cardiologists (Figure 1). Conclusions: Most DCCs performed at this academic hospital are adherent with AUC criteria, however variability exists by indication and provider type. Unclassified patients as mentioned above who got referred for DCC by treating cardiologists led to a significant change in their management plan, thereby suggesting these group of patients which currently do not fit to any subset AUC criteria need consideration for further subset AUC categorization. About 22% of the DCC performed in the suspected CAD group were uncertain, none were inappropriate which make our results prominently discordant to recent findings observed among DCC procedures performed for suspected CAD in New York State.

Clinical and prognostic value of stress echocardiography appropriateness criteria for evaluation of coronary artery disease in a tertiary referral centre

ObjectiveAppropriateness criteria for stress echocardiography (SE) have been published to reduce the rate of inappropriate testing. We sought to investigate the clinical impact and prognostic value of these criteria.Methods250 consecutive...

Abstract 18308: Prognostic Value of Stress Echocardiography Appropriateness Criteria for Evaluation of Coronary Artery Disease

Background: Appropriateness criteria for stress echocardiography (SE) have been published to reduce the rate of inappropriate testing. There are limited data validating the prognostic value of these criteria in clinical practice. Methods: 250 consecutive patients undergoing SE for evaluation of known or suspected coronary artery disease were classified into appropriate, uncertain and inappropriate categories according to appropriateness criteria guidelines. A positive SE was defined as the development of new wall motion abnormalities or a biphasic response. The primary end-point was the composite of myocardial infarction and death. Results: Of the 250 SE, 120 (48%) were dobutamine studies and 130 (52%) were exercise studies. Of the 250 patients, 156 (62.4%), 71 (28.4%) and 23 (9.2%) were classified as appropriate, inappropriate and uncertain, respectively. A significantly greater proportion of studies classified as appropriate 71(45.5%) demonstrated inducible ischaemia compared to inappropriate studies 9(12.7%) or uncertain studies 4(17.4%), p<0.0001. During a median follow-up of 12.4 months (inter-quartile range 10.6 - 16.3 months), events occurred in 18 (11.5%), 2 (2.8%) and 0 patients classified as appropriate, inappropriate and uncertain respectively. Event-free survival was significantly reduced in patients with a SE demonstrating ischaemia compared to patients without inducible ischaemia, p <0.0001. Kaplan Meier curves demonstrated reduced event-free survival in patients with whose studies were classified as appropriate compared to inappropriate (p=0.01) or uncertain (p=0.05). There was no difference in event free survival between those classified as uncertain or inappropriate (p=0.48). The only independent predictors of mortality or myocardial infarction were a positive SE (hazard ratio 5.39) and left ventricular ejection fraction (hazard ratio 0.95). Conclusion: Appropriateness criteria for evaluation of coronary artery disease have the ability to both determine the need for stress testing and identify patients at high risk of ischaemia, subsequent revascularisation and cardiac events.

152 CLINICAL UTILITY AND PROGNOSTIC VALUE OF APPROPRIATENESS CRITERIA IN STRESS ECHOCARDIOGRAPHY FOR EVALUATION OF VALVULAR HEART DISEASE

Background Appropriateness criteria for patients undergoing stress echocardiography (SE) have recently been published. We sought to identify the clinical and prognostic value of these criteria for evaluation of valvular heart disease (VHD). Methods 80 consecutive patients undergoing SE for evaluation of VHD were identified. A positive SE was defined according to VHD guidelines. Patients were classified into appropriate, uncertain and inappropriate categories also according to appropriateness criteria guidelines. The end-point was the composite of valve intervention or death. Results Of the 80 pts undergoing SE, 39 (48.8%), 33 (41.2%) and 8 (10%) were classified as appropriate, uncertain and inappropriate, respectively. A positive SE was identified in 27 (34%) pts, of which a significantly greater proportion of positive SE occurred in patients classified as appropriate 15 (56%) or uncertain 12 (44%) compared to patients classified as inappropriate 0(0%), p Conclusions SE for VHD has prognostic value when incorporated into clinical practice. The Appropriateness criteria for evaluation of VHD provide the ability to differentiate between patients at high (appropriate group) and low risk (inappropriate group) of subsequent cardiac events. Re-classification of the uncertain group may improve the differential value of these criteria and improve their applicability to current clinical practice.

Imposture: A Late Modern Notion in Poststructuralist SLA Research

This article explores the feelings of imposture that are sometimes experienced by multilingual subjects—learners of a language other than their own or users of multiple languages—and their difficulty of finding authentic or legitimate subject positions in a global world with fluid boundaries and uncertain categories of identity. It examines what modernist and poststructuralist approaches to the problem of imposture can yield in applied linguistic theory. Modernist scholars focus on revealing abuses of institutional power and on uncovering the artificiality of language rituals, whereas poststructuralist scholars seek to understand the social and historical conditions of possibility of discourses of imposture. They attempt to deal with the pervasive contradictions of the search for authenticity and legitimacy in a world of commodified discourses and self-declared authorities. In such a world, multilingual subjects have a particular role to play to transform imposture into the multilingual art of interrogating and imagining various forms of discourse.

Correlation of Thyroid Cytology with Surgical Histology

Objective: 1) To assess the predictive value of thyroid cytology by fine needle aspiration (FNA) at our institution in detecting thyroid malignancy since the introduction of the Bethesda System. 2) To identify other potential predictors of malignancy. Method: Records of patients who underwent thyroid FNA and subsequent surgery at University of Missouri between 2007 and 2012 were reviewed. Data collected included cytologic and pathologic diagnoses as well as potential predictors of malignancy and demographic data, including radiation exposure, radiologic findings of calcification and increased vascularity, age, and gender. Results: A total of 378 cases were eligible for review. Of these, one-third met inclusion criteria. Cytology characterized as malignant or benign were found to have high concordance with surgical pathology findings. The diagnosis atypia of undetermined significance (AUS) and its malignancy risk were observed 2 to 3 times higher than that prescribed by the Bethesda guidelines. The majority of cases with cytologic features of follicular neoplasm were found to be benign. However, a significant number of incidental cases of papillary microcarcinoma were observed within this group. Papillary thyroid carcinoma was identified in 60% of cases with features suspicious for malignancy. Conclusion: While benign and malignant cytologies are highly predictive, there exists wide variation in the interpretation of uncertain categories. Malignancy risk associated with AUS ranges from 6% to 28% in the literature. These results suggest that trends developed from institution-specific data may be more predictive in guiding post-FNA management.

Reasoning with uncertain categories

Five experiments investigated how people use categories to make inductions about objects whose categorisation is uncertain. Normatively, they should consider all the categories the object might be in and use a weighted combination of information from all the categories: bet-hedging. The experiments presented people with simple, artificial categories and asked them to make an induction about a new object that was most likely in one category but possibly in another. The results showed that the majority of people focused on the most likely category in making inductions, although there was a group of consistently normative responders who used information from both categories (about 25% of our college population). Across experiments the overall pattern of results suggests that performance in the task is improved not by understanding the underlying principles of bet-hedging but by increasing the likelihood that multiple categories are in working memory at the time of the induction. We discuss implications for improving everyday inductions.

Feature-based versus category-based induction with uncertain categories.

Previous research has suggested that when feature inferences have to be made about an instance whose category membership is uncertain, feature-based inductive reasoning is used to the exclusion of category-based induction. These results contrast with the observation that people can and do use category-based induction when category membership is known. The present experiments examined the conditions that drive feature-based and category-based strategies in induction under category uncertainty. Specifically, 2 experiments investigated whether reliance on feature-based inductive strategies is a product of the lack of coherence in the categories used in previous research or is due to the use of a decision-only induction procedure. Experiment 1 found that feature-based reasoning remained the preferred strategy even when categories with relatively high internal coherence were used. Experiment 2 found a shift toward category-based reasoning when participants were trained to classify category members prior to feature induction. Together, these results suggest that an appropriate conceptual representation must be formed through experience with a category before it is likely to be used as a basis for feature induction.

Where to look first for an explanation of induction with uncertain categories

Recent research has examined how people predict unobserved features of an object when its category membership is ambiguous. The debate has focused on whether predictions are based solely on information from the most likely category, or whether information from other possible categories is also used. In the present experiment, we compared these category-based approaches with feature conjunction reasoning, where predictions are based on a comparison among exemplars (rather than categories) that share features with a target object. Reasoning strategies were assessed by examining patterns of feature prediction and by using an eye gaze measure of attention during induction. The main findings were (1) the majority of participants used feature conjunction rather than categorical strategies, (2) people predominantly gazed at the exemplars that were most similar to the target object, and (3) although people gazed most at the most probable category to which an object could belong, they also attended to other plausible category alternatives during induction. These findings question the extent to which category-based reasoning is used for induction when category membership is uncertain.

Retrospective Occupational Exposure Assessment for Case-Control and Case-Series Epidemiology Studies Based in Shanghai China

To provide exposure information for epidemiology studies conducted in Shanghai from 2001 to 2008, we completed retrospective exposure assessments (EA) of benzene and other hazards. Interviewers administered questionnaires to subjects from Shanghai area hospitals. An initial exposure screening by EA staff members, blinded as to case-control status, stratified jobs into exposed, unexposed, or uncertain categories prior to review by a separate expert panel (EP). Resources for the EA included job/industry-specific questionnaire responses by subjects, short-term benzene area concentration measurements from a Shanghai regulatory agency database, Chinese literature for qualitative and short-term quantitative measurements, on-site investigations, summaries of technology changes, and selected task simulations with concurrent benzene concentration measurements. An EP in Shanghai completed semi-quantitative benzene exposure assignments, with categories of 0 to 4 corresponding to intensity ranges of none, <1, 1 to 10, >10 to 100, and >100 mg/m3. For other hazards, sources included the EP's knowledge of the industries and Chinese and Western literature. For benzene, 20% of the EAs selected by a stratified random process were evaluated by two alternate methods. The study database of potential cases and controls included 18,857 jobs from the subjects’ work histories. From 818 individuals initially screened as probably benzene exposed, 964 jobs underwent further review. From subjects with final diagnoses, 755 jobs qualified for inclusion in the final database for any study. For other exposures, the EA considered 17,893 jobs from 7654 subjects for possible exposures and were in the final study database. Of these, 2565 individuals had exposures of study interest from their 4909 exposed jobs. The prevalent exposures included agricultural chemicals, petroleum products, and metals. The EA involved extensive information assembly and exposure assignment by an EP and periodic reviews. The methods described went beyond those typically applied in past general population studies and may have provided improved information for the epidemiologic analyses. However, sufficient, reliable measured historical data are lacking to evaluate this conclusion.

Inductive reasoning.

Inductive reasoning entails using existing knowledge or observations to make predictions about novel cases. We review recent findings in research on category-based induction as well as theoretical models of these results, including similarity-based models, connectionist networks, an account based on relevance theory, Bayesian models, and other mathematical models. A number of touchstone empirical phenomena that involve taxonomic similarity are described. We also examine phenomena involving more complex background knowledge about premises and conclusions of inductive arguments and the properties referenced. Earlier models are shown to give a good account of similarity-based phenomena but not knowledge-based phenomena. Recent models that aim to account for both similarity-based and knowledge-based phenomena are reviewed and evaluated. Among the most important new directions in induction research are a focus on induction with uncertain premise categories, the modeling of the relationship between inductive and deductive reasoning, and examination of the neural substrates of induction. A common theme in both the well-established and emerging lines of induction research is the need to develop well-articulated and empirically testable formal models of induction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

Induction with uncertain categories: When do people consider the category alternatives?

These three experiments examined how people make property inferences about exemplars whose category membership is uncertain. Participants were shown two categories and a novel exemplar with a feature that indicated that the exemplar was more likely to belong to one category (target) than to the other (nontarget). Participants then made categorization decisions and property inferences about the novel exemplar. In some conditions, property inferences could be made only by considering both target and nontarget categories. In other conditions, predictions could be based on both categories or on the target category alone. Consistent with previous studies (e.g., Murphy & Ross, 1994, 2005), we found that many people made predictions based only on consideration of the target category. However, the prevalence of such single-category reasoning was greatly reduced by highlighting the costs of neglecting nontarget alternatives and by asking for inferences before categorization decisions. The results suggest that previous work may have exaggerated the prevalence of single-category reasoning and that people may be more flexible in their use of multiple categories in property inference than has been previously recognized.

Gated Cardiac CT is Useful for Assessment of Mechanical Aortic Valve Obstruction

single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). We aimed to evaluate the application of AC in an Asian urban academic hospital setting. Methods: 300 consecutive patients referred for SPECT MPIwere analyzed in a prospectivemanner. Based onAC, indications of tests were scored as having an appropriate, uncertain or inappropriate indication. Imaging results were noted. Results: Overall, 235 (78.3%) tests were determined to be appropriate, 42 (14.0%) were inappropriate, 16 (5.3%) were uncertain and 7 (2.3%) were unclassifiable. Patients in the inappropriate groupwere younger than those in the appropriate group (p< 0.001). The most common indication for inappropriate testingwas thedetectionof coronary disease in asymptomatic low-risk patients. There is a higher proportion of normal test results obtained in the inappropriate group (81%) than in the appropriate group (60%) (p= 0.009). There remained a substantial proportion of abnormal results in the inappropriate group (19%), which occurred more frequently in men than in women (p= 0.003). Conclusion: In the application of AC in this single Asian academic hospital setting, a high proportion of testingwas appropriate. Theprospective use ofAC is feasible andmay improve quality of care, butmay lead tomisses in relevant findings in the inappropriate group. Future studies should be directed towards refining the inappropriate and uncertain categories of the AC, and identifying strategies aimed at reducing inappropriate testing. doi:10.1016/j.hlc.2009.05.075

Clinical expertise and reasoning with uncertain categories

Expert clinical psychologists, clinical psychology graduates, and nonclinical graduate students were presented with clinical and nonclinical cases in which the diagnosis or category membership of a character was uncertain; they then made feature predictions about the character. For each case, there was a diagnosis or category that was highly probable and a less likely alternative that either did (relevant condition) or did not (neutral condition) alter predictions. For clinical cases, clinical experts and graduate clinicians gave different predictions for the relevant and neutral conditions, indicating that they had considered the uncertain nature of the diagnosis in their predictions. Although they acknowledged that the diagnosis was uncertain, nonclinical students ignored the less likely diagnostic alternatives when making predictions. For the nonclinical cases, all three groups made predictions based on only the most likely category alternative. The results showed that clinical training and/or experience promote multiple-category reasoning, but that this effect is domain specific.

ROBUSTNESS OF THE REGRESSION MODELS FOR UNCERTAIN CATEGORIES

Dichotomization of the outcome by a single cut-off point is an important part of medical studies. Usually the relationship between the resulted dichotomized dependent variable and explanatory variables is analyzed with linear regression, probit or logistic regression. However, in many real-life situations, a certain cut-off point is unknown and can be specified only approximately, i.e. surrounded by some (small) uncertainty. It means that in order to have any practical meaning the regression model must be robust to this uncertainty. In this paper, we test the robustness of the linear regression model and get that neither the beta in the model, nor its significance level is robust to the small variations in the dichotomization cut-off point. As an alternative robust approach to the problem of uncertain categories, we propose to make use of the linear regression model with the fuzzy membership function as a dependent variable. In the paper, we test the robustness of the linear regression model of such fuzzy dependent variable and get that this model can be insensitive against the uncertainty in the cut-off point location. To demonstrate theoretical conclusions, in the paper we present the modelling results from the real study of low haemoglobin levels in infants.

Uncertainty in Agricultural CH4 AND N2O Emissions from Finland – Possibilities to Increase Accuracy in Emission Estimates

According to the United Nations Framework Convention on Climate Change (UNFCCC) and Kyoto Protocol under it, industrial countries have to estimate their greenhouse gas emissions annually, and assess the uncertainties in these estimates. In Finland, agricultural methane (CH4) and nitrous oxide (N2O) emissions represent 7% of anthropogenic greenhouse gas emissions, and globally the share is much higher. Agriculture is one of the most uncertain emission categories (representing over 20% of greenhouse gas inventory uncertainty in Finland), due to both high natural variability of the emission sources and poor knowledge of the emission-generating processes. In this paper, we present an uncertainty estimate of agricultural CH4 and N2O emissions from Finland in 2002. Uncertainties were estimated based on measurement data, literature and expert judgement, and total uncertainty in agriculture was calculated using Monte Carlo simulation. According to the calculations, agricultural CH4 and N2O emissions from Finland were 3.7 to 7.8 Tg carbon dioxide (CO2) equivalents, 5.4 Tg being the mean value.Estimates of CH4 emissions are more reliable than those of N2O. N2O from agricultural soils was the most uncertain emission category, and the uncertainty was not reduced by using available national measurement data of N2O fluxes. Sensitivity study revealed that the uncertainty in total agricultural inventory could be 7% points lower, if more accurate emission estimation methods were used, including 1) improved data collection in area estimates of organic soils, 2) climate-specific methods for N2O from agricultural soils as already presented in literature, and 3) more detailed CH4 estimation methods for enteric fermentation which can be achieved by investigating national circumstances and digestible systems of animals in more detail.