Sample records for accuracy studies quadas

  1. QUADAS and STARD: evaluating the quality of diagnostic accuracy studies.

    PubMed

    Oliveira, Maria Regina Fernandes de; Gomes, Almério de Castro; Toscano, Cristiana Maria

    2011-04-01

    To compare the performance of two approaches, one based on the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) and another on the Standards for Reporting Studies of Diagnostic Accuracy (STARD), in evaluating the quality of studies validating the OptiMal® rapid malaria diagnostic test. Articles validating the rapid test published until 2007 were searched in the Medline/PubMed database. This search retrieved 13 articles. A combination of 12 QUADAS criteria and three STARD criteria were compared with the 12 QUADAS criteria alone. Articles that fulfilled at least 50% of QUADAS criteria were considered as regular to good quality. Of the 13 articles retrieved, 12 fulfilled at least 50% of QUADAS criteria, and only two fulfilled the STARD/QUADAS criteria combined. Considering the two criteria combination (> 6 QUADAS and > 3 STARD), two studies (15.4%) showed good methodological quality. The articles selection using the proposed combination resulted in two to eight articles, depending on the number of items assumed as cutoff point. The STARD/QUADAS combination has the potential to provide greater rigor when evaluating the quality of studies validating malaria diagnostic tests, given that it incorporates relevant information not contemplated in the QUADAS criteria alone.

  2. [Risk on bias assessment: (6) A Revised Tool for the Quality Assessment on Diagnostic Accuracy Studies (QUADAS-2)].

    PubMed

    Qu, Y J; Yang, Z R; Sun, F; Zhan, S Y

    2018-04-10

    This paper introduced the Revised Tool for the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2), including the development and comparison with the original QUADAS, and illustrated the application of QUADAS-2 in a published paper related to the study on diagnostic accuracy which was included in systematic review and Meta-analysis. QUADAS-2 presented considerable improvement over the original tool. Confused items that included in QUADAS had disappeared and the quality assessment of the original study replaced by the rating of risk on bias and applicability. This was implemented through the description on the four main domains with minimal overlapping and answering the signal questions in each domain. The risk of bias and applicability with 'high','low' or 'unclear' was in line with the risk of bias assessment of intervention studies in Cochrane, so to replace the total score of quality assessment in QUADAS. Meanwhile, QUADAS-2 was also applicable to assess the diagnostic accuracy studies in which follow-up without prognosis was involved in golden standard. It was useful to assess the overall methodological quality of the study despite more time consuming than the original QUADAS. However, QUADAS-2 needs to be modified to apply in comparative studies on diagnostic accuracy and we hope the users would follow the updates and give their feedbacks on line.

  3. A systematic review of the PTSD Checklist's diagnostic accuracy studies using QUADAS.

    PubMed

    McDonald, Scott D; Brown, Whitney L; Benesek, John P; Calhoun, Patrick S

    2015-09-01

    Despite the popularity of the PTSD Checklist (PCL) as a clinical screening test, there has been no comprehensive quality review of studies evaluating its diagnostic accuracy. A systematic quality assessment of 22 diagnostic accuracy studies of the English-language PCL using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) assessment tool was conducted to examine (a) the quality of diagnostic accuracy studies of the PCL, and (b) whether quality has improved since the 2003 STAndards for the Reporting of Diagnostic accuracy studies (STARD) initiative regarding reporting guidelines for diagnostic accuracy studies. Three raters independently applied the QUADAS tool to each study, and a consensus among the 4 authors is reported. Findings indicated that although studies generally met standards in several quality areas, there is still room for improvement. Areas for improvement include establishing representativeness, adequately describing clinical and demographic characteristics of the sample, and presenting better descriptions of important aspects of test and reference standard execution. Only 2 studies met each of the 14 quality criteria. In addition, study quality has not appreciably improved since the publication of the STARD Statement in 2003. Recommendations for the improvement of diagnostic accuracy studies of the PCL are discussed. (c) 2015 APA, all rights reserved).

  4. Quality Assessment of Comparative Diagnostic Accuracy Studies: Our Experience Using a Modified Version of the QUADAS-2 Tool

    ERIC Educational Resources Information Center

    Wade, Ros; Corbett, Mark; Eastwood, Alison

    2013-01-01

    Assessing the quality of included studies is a vital step in undertaking a systematic review. The recently revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool (QUADAS-2), which is the only validated quality assessment tool for diagnostic accuracy studies, does not include specific criteria for assessing comparative studies. As…

  5. Methodological quality of diagnostic accuracy studies on non-invasive coronary CT angiography: influence of QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) items on sensitivity and specificity.

    PubMed

    Schueler, Sabine; Walther, Stefan; Schuetz, Georg M; Schlattmann, Peter; Dewey, Marc

    2013-06-01

    To evaluate the methodological quality of diagnostic accuracy studies on coronary computed tomography (CT) angiography using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies included in systematic reviews) tool. Each QUADAS item was individually defined to adapt it to the special requirements of studies on coronary CT angiography. Two independent investigators analysed 118 studies using 12 QUADAS items. Meta-regression and pooled analyses were performed to identify possible effects of methodological quality items on estimates of diagnostic accuracy. The overall methodological quality of coronary CT studies was merely moderate. They fulfilled a median of 7.5 out of 12 items. Only 9 of the 118 studies fulfilled more than 75 % of possible QUADAS items. One QUADAS item ("Uninterpretable Results") showed a significant influence (P = 0.02) on estimates of diagnostic accuracy with "no fulfilment" increasing specificity from 86 to 90 %. Furthermore, pooled analysis revealed that each QUADAS item that is not fulfilled has the potential to change estimates of diagnostic accuracy. The methodological quality of studies investigating the diagnostic accuracy of non-invasive coronary CT is only moderate and was found to affect the sensitivity and specificity. An improvement is highly desirable because good methodology is crucial for adequately assessing imaging technologies. • Good methodological quality is a basic requirement in diagnostic accuracy studies. • Most coronary CT angiography studies have only been of moderate design quality. • Weak methodological quality will affect the sensitivity and specificity. • No improvement in methodological quality was observed over time. • Authors should consider the QUADAS checklist when undertaking accuracy studies.

  6. Quality and reporting of diagnostic accuracy studies in TB, HIV and malaria: evaluation using QUADAS and STARD standards.

    PubMed

    Fontela, Patricia Scolari; Pant Pai, Nitika; Schiller, Ian; Dendukuri, Nandini; Ramsay, Andrew; Pai, Madhukar

    2009-11-13

    Poor methodological quality and reporting are known concerns with diagnostic accuracy studies. In 2003, the QUADAS tool and the STARD standards were published for evaluating the quality and improving the reporting of diagnostic studies, respectively. However, it is unclear whether these tools have been applied to diagnostic studies of infectious diseases. We performed a systematic review on the methodological and reporting quality of diagnostic studies in TB, malaria and HIV. We identified diagnostic accuracy studies of commercial tests for TB, malaria and HIV through a systematic search of the literature using PubMed and EMBASE (2004-2006). Original studies that reported sensitivity and specificity data were included. Two reviewers independently extracted data on study characteristics and diagnostic accuracy, and used QUADAS and STARD to evaluate the quality of methods and reporting, respectively. Ninety (38%) of 238 articles met inclusion criteria. All studies had design deficiencies. Study quality indicators that were met in less than 25% of the studies included adequate description of withdrawals (6%) and reference test execution (10%), absence of index test review bias (19%) and reference test review bias (24%), and report of uninterpretable results (22%). In terms of quality of reporting, 9 STARD indicators were reported in less than 25% of the studies: methods for calculation and estimates of reproducibility (0%), adverse effects of the diagnostic tests (1%), estimates of diagnostic accuracy between subgroups (10%), distribution of severity of disease/other diagnoses (11%), number of eligible patients who did not participate in the study (14%), blinding of the test readers (16%), and description of the team executing the test and management of indeterminate/outlier results (both 17%). The use of STARD was not explicitly mentioned in any study. Only 22% of 46 journals that published the studies included in this review required authors to use STARD. Recently

  7. Quality and Reporting of Diagnostic Accuracy Studies in TB, HIV and Malaria: Evaluation Using QUADAS and STARD Standards

    PubMed Central

    Fontela, Patricia Scolari; Pant Pai, Nitika; Schiller, Ian; Dendukuri, Nandini; Ramsay, Andrew; Pai, Madhukar

    2009-01-01

    Background Poor methodological quality and reporting are known concerns with diagnostic accuracy studies. In 2003, the QUADAS tool and the STARD standards were published for evaluating the quality and improving the reporting of diagnostic studies, respectively. However, it is unclear whether these tools have been applied to diagnostic studies of infectious diseases. We performed a systematic review on the methodological and reporting quality of diagnostic studies in TB, malaria and HIV. Methods We identified diagnostic accuracy studies of commercial tests for TB, malaria and HIV through a systematic search of the literature using PubMed and EMBASE (2004–2006). Original studies that reported sensitivity and specificity data were included. Two reviewers independently extracted data on study characteristics and diagnostic accuracy, and used QUADAS and STARD to evaluate the quality of methods and reporting, respectively. Findings Ninety (38%) of 238 articles met inclusion criteria. All studies had design deficiencies. Study quality indicators that were met in less than 25% of the studies included adequate description of withdrawals (6%) and reference test execution (10%), absence of index test review bias (19%) and reference test review bias (24%), and report of uninterpretable results (22%). In terms of quality of reporting, 9 STARD indicators were reported in less than 25% of the studies: methods for calculation and estimates of reproducibility (0%), adverse effects of the diagnostic tests (1%), estimates of diagnostic accuracy between subgroups (10%), distribution of severity of disease/other diagnoses (11%), number of eligible patients who did not participate in the study (14%), blinding of the test readers (16%), and description of the team executing the test and management of indeterminate/outlier results (both 17%). The use of STARD was not explicitly mentioned in any study. Only 22% of 46 journals that published the studies included in this review required

  8. The methodological quality of diagnostic test accuracy studies for musculoskeletal conditions can be improved.

    PubMed

    Henschke, Nicholas; Keuerleber, Julia; Ferreira, Manuela; Maher, Christopher G; Verhagen, Arianne P

    2014-04-01

    To provide an overview of reporting and methodological quality in diagnostic test accuracy (DTA) studies in the musculoskeletal field and evaluate the use of the QUality Assessment of Diagnostic Accuracy Studies (QUADAS) checklist. A literature review identified all systematic reviews that evaluated the accuracy of clinical tests to diagnose musculoskeletal conditions and used the QUADAS checklist. Two authors screened all identified reviews and extracted data on the target condition, index tests, reference standard, included studies, and QUADAS items. A descriptive analysis of the QUADAS checklist was performed, along with Rasch analysis to examine the construct validity and internal reliability. A total of 19 systematic reviews were included, which provided data on individual items of the QUADAS checklist for 392 DTA studies. In the musculoskeletal field, uninterpretable or intermediate test results are commonly not reported, with 175 (45%) studies scoring "no" to this item. The proportion of studies fulfilling certain items varied from 22% (item 11) to 91% (item 3). The interrater reliability of the QUADAS checklist was good and Rasch analysis showed excellent construct validity and internal consistency. This overview identified areas where the reporting and performance of diagnostic studies within the musculoskeletal field can be improved. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Evaluation of the methodological quality of studies of the performance of diagnostic tests for bovine tuberculosis using QUADAS.

    PubMed

    Downs, Sara H; More, Simon J; Goodchild, Anthony V; Whelan, Adam O; Abernethy, Darrell A; Broughan, Jennifer M; Cameron, Angus; Cook, Alasdair J; Ricardo de la Rua-Domenech, R; Greiner, Matthias; Gunn, Jane; Nuñez-Garcia, Javier; Rhodes, Shelley; Rolfe, Simon; Sharp, Michael; Upton, Paul; Watson, Eamon; Welsh, Michael; Woolliams, John A; Clifton-Hadley, Richard S; Parry, Jessica E

    2018-05-01

    There has been little assessment of the methodological quality of studies measuring the performance (sensitivity and/or specificity) of diagnostic tests for animal diseases. In a systematic review, 190 studies of tests for bovine tuberculosis (bTB) in cattle (published 1934-2009) were assessed by at least one of 18 reviewers using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies) checklist adapted for animal disease tests. VETQUADAS (VQ) included items measuring clarity in reporting (n = 3), internal validity (n = 9) and external validity (n = 2). A similar pattern for compliance was observed in studies of different diagnostic test types. Compliance significantly improved with year of publication for all items measuring clarity in reporting and external validity but only improved in four of the nine items measuring internal validity (p < 0.05). 107 references, of which 83 had performance data eligible for inclusion in a meta-analysis were reviewed by two reviewers. In these references, agreement between reviewers' responses was 71% for compliance, 32% for unsure and 29% for non-compliance. Mean compliance with reporting items was 2, 5.2 for internal validity and 1.5 for external validity. The index test result was described in sufficient detail in 80.1% of studies and was interpreted without knowledge of the reference standard test result in only 33.1%. Loss to follow-up was adequately explained in only 31.1% of studies. The prevalence of deficiencies observed may be due to inadequate reporting but may also reflect lack of attention to methodological issues that could bias the results of diagnostic test performance estimates. QUADAS was a useful tool for assessing and comparing the quality of studies measuring the performance of diagnostic tests but might be improved further by including explicit assessment of population sampling strategy. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  10. Methodology and reporting of diagnostic accuracy studies of automated perimetry in glaucoma: evaluation using a standardised approach.

    PubMed

    Fidalgo, Bruno M R; Crabb, David P; Lawrenson, John G

    2015-05-01

    To evaluate methodological and reporting quality of diagnostic accuracy studies of perimetry in glaucoma and to determine whether there had been any improvement since the publication of the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines. A systematic review of English language articles published between 1993 and 2013 reporting the diagnostic accuracy of perimetry in glaucoma. Articles were appraised for methodological quality using the 14-item Quality assessment tool for diagnostic accuracy studies (QUADAS) and evaluated for quality of reporting by applying the STARD checklist. Fifty-eight articles were appraised. Overall methodological quality of these studies was moderate with a median number of QUADAS items rated as 'yes' equal to nine (out of a maximum of 14) (IQR 7-10). The studies were often poorly reported; median score of STARD items fully reported was 11 out of 25 (IQR 10-14). A comparison of the studies published in 10-year periods before and after the publication of the STARD checklist in 2003 found quality of reporting had not substantially improved. Methodological and reporting quality of diagnostic accuracy studies of perimetry is sub-optimal and appears not to have improved substantially following the development of the STARD reporting guidance. This observation is consistent with previous studies in ophthalmology and in other medical specialities. © 2015 The Authors Ophthalmic & Physiological Optics © 2015 The College of Optometrists.

  11. Diagnostic accuracy of physical examination tests of the ankle/foot complex: a systematic review.

    PubMed

    Schwieterman, Braun; Haas, Deniele; Columber, Kirby; Knupp, Darren; Cook, Chad

    2013-08-01

    Orthopedic special tests of the ankle/foot complex are routinely used during the physical examination process in order to help diagnose ankle/lower leg pathologies. The purpose of this systematic review was to investigate the diagnostic accuracy of ankle/lower leg special tests. A search of the current literature was conducted using PubMed, CINAHL, SPORTDiscus, ProQuest Nursing and Allied Health Sources, Scopus, and Cochrane Library. Studies were eligible if they included the following: 1) a diagnostic clinical test of musculoskeletal pathology in the ankle/foot complex, 2) description of the clinical test or tests, 3) a report of the diagnostic accuracy of the clinical test (e.g. sensitivity and specificity), and 4) an acceptable reference standard for comparison. The quality of included studies was determined by two independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Nine diagnostic accuracy studies met the inclusion criteria for this systematic review; analyzing a total of 16 special tests of the ankle/foot complex. After assessment using the QUADAS-2, only one study had low risk of bias and low concerns regarding applicability. Most ankle/lower leg orthopedic special tests are confirmatory in nature and are best utilized at the end of the physical examination. Most of the studies included in this systematic review demonstrate notable biases, which suggest that results and recommendations in this review should be taken as a guide rather than an outright standard. There is need for future research with more stringent study design criteria so that more accurate diagnostic power of ankle/lower leg special tests can be determined. 3a.

  12. DIAGNOSTIC ACCURACY OF PHYSICAL EXAMINATION TESTS OF THE ANKLE/FOOT COMPLEX: A SYSTEMATIC REVIEW

    PubMed Central

    Schwieterman, Braun; Haas, Deniele; Columber, Kirby; Knupp, Darren

    2013-01-01

    Background: Orthopedic special tests of the ankle/foot complex are routinely used during the physical examination process in order to help diagnose ankle/lower leg pathologies. Purpose: The purpose of this systematic review was to investigate the diagnostic accuracy of ankle/lower leg special tests. Methods: A search of the current literature was conducted using PubMed, CINAHL, SPORTDiscus, ProQuest Nursing and Allied Health Sources, Scopus, and Cochrane Library. Studies were eligible if they included the following: 1) a diagnostic clinical test of musculoskeletal pathology in the ankle/foot complex, 2) description of the clinical test or tests, 3) a report of the diagnostic accuracy of the clinical test (e.g. sensitivity and specificity), and 4) an acceptable reference standard for comparison. The quality of included studies was determined by two independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Results: Nine diagnostic accuracy studies met the inclusion criteria for this systematic review; analyzing a total of 16 special tests of the ankle/foot complex. After assessment using the QUADAS-2, only one study had low risk of bias and low concerns regarding applicability. Conclusion: Most ankle/lower leg orthopedic special tests are confirmatory in nature and are best utilized at the end of the physical examination. Most of the studies included in this systematic review demonstrate notable biases, which suggest that results and recommendations in this review should be taken as a guide rather than an outright standard. There is need for future research with more stringent study design criteria so that more accurate diagnostic power of ankle/lower leg special tests can be determined. Level of Evidence: 3a PMID:24175128

  13. The methodological quality of three foundational law enforcement Drug Influence Evaluation validation studies.

    PubMed

    Kane, Greg

    2013-11-04

    A Drug Influence Evaluation (DIE) is a formal assessment of an impaired driving suspect, performed by a trained law enforcement officer who uses circumstantial facts, questioning, searching, and a physical exam to form an unstandardized opinion as to whether a suspect's driving was impaired by drugs. This paper first identifies the scientific studies commonly cited in American criminal trials as evidence of DIE accuracy, and second, uses the QUADAS tool to investigate whether the methodologies used by these studies allow them to correctly quantify the diagnostic accuracy of the DIEs currently administered by US law enforcement. Three studies were selected for analysis. For each study, the QUADAS tool identified biases that distorted reported accuracies. The studies were subject to spectrum bias, selection bias, misclassification bias, verification bias, differential verification bias, incorporation bias, and review bias. The studies quantified DIE performance with prevalence-dependent accuracy statistics that are internally but not externally valid. The accuracies reported by these studies do not quantify the accuracy of the DIE process now used by US law enforcement. These studies do not validate current DIE practice.

  14. Screening for bipolar spectrum disorders: A comprehensive meta-analysis of accuracy studies.

    PubMed

    Carvalho, André F; Takwoingi, Yemisi; Sales, Paulo Marcelo G; Soczynska, Joanna K; Köhler, Cristiano A; Freitas, Thiago H; Quevedo, João; Hyphantis, Thomas N; McIntyre, Roger S; Vieta, Eduard

    2015-02-01

    Bipolar spectrum disorders are frequently under-recognized and/or misdiagnosed in various settings. Several influential publications recommend the routine screening of bipolar disorder. A systematic review and meta-analysis of accuracy studies for the bipolar spectrum diagnostic scale (BSDS), the hypomania checklist (HCL-32) and the mood disorder questionnaire (MDQ) were performed. The Pubmed, EMBASE, Cochrane, PsycINFO and SCOPUS databases were searched. Studies were included if the accuracy properties of the screening measures were determined against a DSM or ICD-10 structured diagnostic interview. The QUADAS-2 tool was used to rate bias. Fifty three original studies met inclusion criteria (N=21,542). At recommended cutoffs, summary sensitivities were 81%, 66% and 69%, while specificities were 67%, 79% and 86% for the HCL-32, MDQ, and BSDS in psychiatric services, respectively. The HCL-32 was more accurate than the MDQ for the detection of type II bipolar disorder in mental health care centers (P=0.018). At a cutoff of 7, the MDQ had a summary sensitivity of 43% and a summary specificity of 95% for detection of bipolar disorder in primary care or general population settings. Most studies were performed in mental health care settings. Several included studies had a high risk of bias. Although accuracy properties of the three screening instruments did not consistently differ in mental health care services, the HCL-32 was more accurate than the MDQ for the detection of type II BD. More studies in other settings (for example, in primary care) are necessary. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The diagnostic accuracy of serological tests for Lyme borreliosis in Europe: a systematic review and meta-analysis.

    PubMed

    Leeflang, M M G; Ang, C W; Berkhout, J; Bijlmer, H A; Van Bortel, W; Brandenburg, A H; Van Burgel, N D; Van Dam, A P; Dessau, R B; Fingerle, V; Hovius, J W R; Jaulhac, B; Meijer, B; Van Pelt, W; Schellekens, J F P; Spijker, R; Stelma, F F; Stanek, G; Verduyn-Lunel, F; Zeller, H; Sprong, H

    2016-03-25

    Interpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe. We searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy. Seventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50% (95% CI 40% to 61%); neuroborreliosis 77% (95% CI 67% to 85%); acrodermatitis chronica atrophicans 97% (95% CI 94% to 99%); unspecified Lyme borreliosis 73% (95% CI 53% to 87%). Specificity was around 95% in studies with healthy controls, but around 80% in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches. The observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

  16. The methodological quality of three foundational law enforcement drug influence evaluation validation studies

    PubMed Central

    2013-01-01

    Background A Drug Influence Evaluation (DIE) is a formal assessment of an impaired driving suspect, performed by a trained law enforcement officer who uses circumstantial facts, questioning, searching, and a physical exam to form an unstandardized opinion as to whether a suspect’s driving was impaired by drugs. This paper first identifies the scientific studies commonly cited in American criminal trials as evidence of DIE accuracy, and second, uses the QUADAS tool to investigate whether the methodologies used by these studies allow them to correctly quantify the diagnostic accuracy of the DIEs currently administered by US law enforcement. Results Three studies were selected for analysis. For each study, the QUADAS tool identified biases that distorted reported accuracies. The studies were subject to spectrum bias, selection bias, misclassification bias, verification bias, differential verification bias, incorporation bias, and review bias. The studies quantified DIE performance with prevalence-dependent accuracy statistics that are internally but not externally valid. Conclusion The accuracies reported by these studies do not quantify the accuracy of the DIE process now used by US law enforcement. These studies do not validate current DIE practice. PMID:24188398

  17. Rapid On-Site Evaluation of Fine-Needle Aspiration by Non-Cytopathologists: A Systematic Review and Meta-Analysis of Diagnostic Accuracy Studies for Adequacy Assessment.

    PubMed

    Pearson, Lauren; Factor, Rachel E; White, Sandra K; Walker, Brandon S; Layfield, Lester J; Schmidt, Robert L

    2018-06-06

    Rapid on-site evaluation (ROSE) has been shown to improve adequacy rates and reduce needle passes. ROSE is often performed by cytopathologists who have limited availability and may be costlier than alternatives. Several recent studies examined the use of alternative evaluators (AEs) for ROSE. A summary of this information could help inform guidelines regarding the use of AEs. The objective was to assess the accuracy of AEs compared to cytopathologists in assessing the adequacy of specimens during ROSE. This was a systematic review and meta-analysis. Reporting and study quality were assessed using the STARD guidelines and QUADAS-2. All steps were performed independently by two evaluators. Summary estimates were obtained using the hierarchal method in Stata v14. Heterogeneity was evaluated using Higgins' I2 statistic. The systematic review identified 13 studies that were included in the meta-analysis. Summary estimates of sensitivity and specificity for AEs were 97% (95% CI: 92-99%) and 83% (95% CI: 68-92%). There was wide variation in accuracy statistics between studies (I2 = 0.99). AEs sometimes have accuracy that is close to cytopathologists. However, there is wide variability between studies, so it is not possible to provide a broad guideline regarding the use of AEs. © 2018 S. Karger AG, Basel.

  18. The Effect of Study Design Biases on the Diagnostic Accuracy of Magnetic Resonance Imaging to Detect Silicone Breast Implant Ruptures: A Meta-Analysis

    PubMed Central

    Song, Jae W.; Kim, Hyungjin Myra; Bellfi, Lillian T.; Chung, Kevin C.

    2010-01-01

    Background All silicone breast implant recipients are recommended by the US Food and Drug Administration to undergo serial screening to detect implant rupture with magnetic resonance imaging (MRI). We performed a systematic review of the literature to assess the quality of diagnostic accuracy studies utilizing MRI or ultrasound to detect silicone breast implant rupture and conducted a meta-analysis to examine the effect of study design biases on the estimation of MRI diagnostic accuracy measures. Method Studies investigating the diagnostic accuracy of MRI and ultrasound in evaluating ruptured silicone breast implants were identified using MEDLINE, EMBASE, ISI Web of Science, and Cochrane library databases. Two reviewers independently screened potential studies for inclusion and extracted data. Study design biases were assessed using the QUADAS tool and the STARDS checklist. Meta-analyses estimated the influence of biases on diagnostic odds ratios. Results Among 1175 identified articles, 21 met the inclusion criteria. Most studies using MRI (n= 10 of 16) and ultrasound (n=10 of 13) examined symptomatic subjects. Meta-analyses revealed that MRI studies evaluating symptomatic subjects had 14-fold higher diagnostic accuracy estimates compared to studies using an asymptomatic sample (RDOR 13.8; 95% CI 1.83–104.6) and 2-fold higher diagnostic accuracy estimates compared to studies using a screening sample (RDOR 1.89; 95% CI 0.05–75.7). Conclusion Many of the published studies utilizing MRI or ultrasound to detect silicone breast implant rupture are flawed with methodological biases. These methodological shortcomings may result in overestimated MRI diagnostic accuracy measures and should be interpreted with caution when applying the data to a screening population. PMID:21364405

  19. ACCURACY OF PLASMA FREE METANEPHRINES IN THE DIAGNOSIS OF PHEOCHROMOCYTOMA AND PARAGANGLIOMA: A SYSTEMATIC REVIEW AND META-ANALYSIS.

    PubMed

    Chen, Yan; Xiao, Huangmeng; Zhou, Xieda; Huang, Xiaoyu; Li, Yanbing; Xiao, Haipeng; Cao, Xiaopei

    2017-10-01

    Various studies have validated plasma free metanephrines (MNs) as biomarkers for pheochromocytoma and paraganglioma (PPGL). This meta-analysis aimed to estimate the overall diagnostic accuracy of this biochemical test for PPGL. We searched the PubMed, the Cochrane Library, Web of Science, Embase, Scopus, OvidSP, and ProQuest Dissertations & Theses databases from January 1, 1995 to December 2, 2016 and selected studies written in English that assessed plasma free MNs in the diagnosis of PPGL. Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) was used to evaluate the quality of the included studies. We calculated pooled sensitivities, specificities, positive and negative likelihood ratios, diagnostic odds ratios (DORs) and areas under curve (AUCs) with their 95% confidence intervals (95% CIs). Heterogeneity was assessed by I 2 . To identify the source of heterogeneity, we evaluated the threshold effect and performed a meta-regression. Deeks' funnel plot was selected for investigating any potential publication bias. Although the combination of metanephrine (MN) and normetanephrine (NMN) carried lower specificity (0.94, 95% CI 0.90-0.97) than NMN (0.97, 95% CI 0.92-0.99), NMN was generally more accurate than individual tests, with the highest AUC (0.99, 95% CI 0.97-0.99), DOR (443.35, 95% CI 216.9-906.23), and pooled sensitivity (0.97, 95% CI 0.94-0.98) values. Threshold effect and meta-regression analyses showed that different cut-offs, blood sampling positions, study types and test methods contributed to heterogeneity. This meta-analysis suggested an effective value for combined plasma free MNs for the diagnosis of PPGL, but testing for MNs requires more standardization using tightly regulated studies. AUC = area under curve; CI = confidence interval; DOR = diagnostic odds ratio; EIA = enzyme immunoassay; LC-ECD = liquid chromatography-electrochemical detection; LC-MS/MS = liquid chromatography-tandem mass spectrometry; MN = metanephrine; NMN

  20. Diagnostic accuracy of contrast-enhanced ultrasound in assessing the therapeutic response to radio frequency ablation for liver tumors: systematic review and meta-analysis.

    PubMed

    Xuan, Min; Zhou, Fengsheng; Ding, Yan; Zhu, Qiaoying; Dong, Ji; Zhou, Hao; Cheng, Jun; Jiang, Xiao; Wu, Pengxi

    2018-04-01

    To review the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) used to detect residual or recurrent liver tumors after radiofrequency ablation (RFA). This technique uses contrast-enhanced computer tomography or/and contrast-enhanced magnetic resonance imaging as the gold standard of investigation. MEDLINE, EMBASE, and COCHRANE were systematically searched for all potentially eligible studies comparing CEUS with the reference standard that follows RFA. Risk of bias and applicability concerns were addressed by adopting the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Pooled point estimates for sensitivity, specificity, positive and negative likelihood ratios, and diagnostic odds ratios (DOR) with 95% CI were computed before plotting the sROC (summary receiver operating characteristic) curve. Meta-regression and subgroup analysis were used to identify the source of the heterogeneity that was detected. Publication bias was evaluated using Deeks' funnel plot asymmetry test. Ten eligible studies on 1162 lesions that occurred between 2001 and 2016 were included in the final analysis. The quality of the included studies assessed by the QUADAS-2 tool was considered reasonable. The pooled sensitivity and specificity of CEUS in detecting residual or recurrent liver tumors had the following values: 0.90 (95% CI 0.85-0.94) and 1.00 (95% CI 0.99-1.00), respectively. Overall DOR was 420.10 (95% CI 142.30-1240.20). The sources of heterogeneity could not be precisely identified by meta-regression or subgroup analysis. No evidence of publication bias was found. This study confirmed that CEUS exhibits high sensitivity and specificity in assessing therapeutic responses to RFA for liver tumors.

  1. Fundus autofluorescence imaging: systematic review of test accuracy for the diagnosis and monitoring of retinal conditions.

    PubMed

    Frampton, G K; Kalita, N; Payne, L; Colquitt, J L; Loveman, E; Downes, S M; Lotery, A J

    2017-07-01

    We conducted a systematic review of the accuracy of fundus autofluorescence (FAF) imaging for diagnosing and monitoring retinal conditions. Searches in November 2014 identified English language references. Sources included MEDLINE, EMBASE, the Cochrane Library, Web of Science, and MEDION databases; reference lists of retrieved studies; and internet pages of relevant organisations, meetings, and trial registries. For inclusion, studies had to report FAF imaging accuracy quantitatively. Studies were critically appraised using QUADAS risk of bias criteria. Two reviewers conducted all review steps. From 2240 unique references identified, eight primary research studies met the inclusion criteria. These investigated diagnostic accuracy of FAF imaging for choroidal neovascularisation (one study), reticular pseudodrusen (three studies), cystoid macular oedema (two studies), and diabetic macular oedema (two studies). Diagnostic sensitivity of FAF imaging ranged from 32 to 100% and specificity from 34 to 100%. However, owing to methodological limitations, including high and/or unclear risks of bias, none of these studies provides conclusive evidence of the diagnostic accuracy of FAF imaging. Study heterogeneity precluded meta-analysis. In most studies, the patient spectrum was not reflective of those who would present in clinical practice and no studies adequately reported whether FAF images were interpreted consistently. No studies of monitoring accuracy were identified. An update in October 2016, based on MEDLINE and internet searches, identified four new studies but did not alter our conclusions. Robust quantitative evidence on the accuracy of FAF imaging and how FAF images are interpreted is lacking. We provide recommendations to address this.

  2. Diagnostic Accuracy of Imaging Modalities and Injection Techniques for the Diagnosis of Femoroacetabular Impingement/Labral Tear: A Systematic Review With Meta-analysis.

    PubMed

    Reiman, Michael P; Thorborg, Kristian; Goode, Adam P; Cook, Chad E; Weir, Adam; Hölmich, Per

    2017-09-01

    Diagnosing femoroacetabular impingement/acetabular labral tear (FAI/ALT) and subsequently making a decision regarding surgery are based primarily on diagnostic imaging and intra-articular hip joint injection techniques of unknown accuracy. Summarize and evaluate the diagnostic accuracy and clinical utility of various imaging modalities and injection techniques relevant to hip FAI/ALT. Systematic review with meta-analysis. A computer-assisted literature search was conducted of MEDLINE, CINAHL, and EMBASE databases using keywords related to diagnostic accuracy of hip joint pathologic changes. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used for the search and reporting phases of the study. Quality assessment of bias and applicability was conducted using the Quality of Diagnostic Accuracy Studies (QUADAS) tool. Random effects models were used to summarize sensitivities (SN), specificities (SP), likelihood ratios (+LR and -LR), diagnostic odds ratios (DOR), and respective confidence intervals (CI). The search strategy and assessment for risk of bias revealed 25 articles scoring above 10/14 on the items of the QUADAS. Four studies investigated FAI, and the data were not pooled. Twenty articles on ALT qualified for meta-analysis. Pretest probability of ALT in the studies in this review was 81% (72%-88%), while the pretest probability of FAI diagnosis was 74% (95% CI, 51%-91%). The meta-analysis showed that computed tomography arthrography (CTA) demonstrated the strongest overall diagnostic accuracy: pooled SN 0.91 (95% CI, 0.83-0.96); SP 0.89 (95% CI, 0.74-0.97); +LR 6.28 (95% CI, 2.78-14.21); -LR 0.11 (95% CI, 0.06-0.21); and DOR 64.38 (95% CI, 19.17-216.21). High pretest probability of disease was demonstrated. Positive imaging findings increased the probability that a labral tear existed by a minimal to small degree with the use of magnetic resonance imaging/magnetic resonance angiogram (MRI/MRA) and ultrasound (US

  3. Macular versus Retinal Nerve Fiber Layer Parameters for Diagnosing Manifest Glaucoma: A Systematic Review of Diagnostic Accuracy Studies.

    PubMed

    Oddone, Francesco; Lucenteforte, Ersilia; Michelessi, Manuele; Rizzo, Stanislao; Donati, Simone; Parravano, Mariacristina; Virgili, Gianni

    2016-05-01

    Macular parameters have been proposed as an alternative to retinal nerve fiber layer (RNFL) parameters to diagnose glaucoma. Comparing the diagnostic accuracy of macular parameters, specifically the ganglion cell complex (GCC) and ganglion cell inner plexiform layer (GCIPL), with the accuracy of RNFL parameters for detecting manifest glaucoma is important to guide clinical practice and future research. Studies using spectral domain optical coherence tomography (SD OCT) and reporting macular parameters were included if they allowed the extraction of accuracy data for diagnosing manifest glaucoma, as confirmed with automated perimetry or a clinician's optic nerve head (ONH) assessment. Cross-sectional cohort studies and case-control studies were included. The QUADAS 2 tool was used to assess methodological quality. Only direct comparisons of macular versus RNFL parameters (i.e., in the same study) were conducted. Summary sensitivity and specificity of each macular or RNFL parameter were reported, and the relative diagnostic odds ratio (DOR) was calculated in hierarchical summary receiver operating characteristic (HSROC) models to compare them. Thirty-four studies investigated macular parameters using RTVue OCT (Optovue Inc., Fremont, CA) (19 studies, 3094 subjects), Cirrus OCT (Carl Zeiss Meditec Inc., Dublin, CA) (14 studies, 2164 subjects), or 3D Topcon OCT (Topcon, Inc., Tokyo, Japan) (4 studies, 522 subjects). Thirty-two of these studies allowed comparisons between macular and RNFL parameters. Studies generally reported sensitivities at fixed specificities, more commonly 0.90 or 0.95, with sensitivities of most best-performing parameters between 0.65 and 0.75. For all OCT devices, compared with RNFL parameters, macular parameters were similarly or slightly less accurate for detecting glaucoma at the highest reported specificity, which was confirmed in analyses at the lowest specificity. Included studies suffered from limitations, especially the case-control study

  4. Diagnostic accuracy of physical examination for anterior knee instability: a systematic review.

    PubMed

    Leblanc, Marie-Claude; Kowalczuk, Marcin; Andruszkiewicz, Nicole; Simunovic, Nicole; Farrokhyar, Forough; Turnbull, Travis Lee; Debski, Richard E; Ayeni, Olufemi R

    2015-10-01

    Determining diagnostic accuracy of Lachman, pivot shift and anterior drawer tests versus gold standard diagnosis (magnetic resonance imaging or arthroscopy) for anterior cruciate ligament (ACL) insufficiency cases. Secondarily, evaluating effects of: chronicity, partial rupture, awake versus anaesthetized evaluation. Searching MEDLINE, EMBASE and PubMed identified studies on diagnostic accuracy for ACL insufficiency. Studies identification and data extraction were performed in duplicate. Quality assessment used QUADAS tool, and statistical analyses were completed for pooled sensitivity and specificity. Eight studies were included. Given insufficient data, pooled analysis was only possible for sensitivity on Lachman and pivot shift test. During awake evaluation, sensitivity for the Lachman test was 89 % (95 % CI 0.76, 0.98) for all rupture types, 96 % (95 % CI 0.90, 1.00) for complete ruptures and 68 % (95 % CI 0.25, 0.98) for partial ruptures. For pivot shift in awake evaluation, results were 79 % (95 % CI 0.63, 0.91) for all rupture types, 86 % (95 % CI 0.68, 0.99) for complete ruptures and 67 % (95 % CI 0.47, 0.83) for partial ruptures. Decreased sensitivity of Lachman and pivot shift tests for partial rupture cases and for awake patients raised suspicions regarding the accuracy of these tests for diagnosis of ACL insufficiency. This may lead to further research aiming to improve the understanding of the true accuracy of these physical diagnostic tests and increase the reliability of clinical investigation for this pathology. IV.

  5. How does study quality affect the results of a diagnostic meta-analysis?

    PubMed Central

    Westwood, Marie E; Whiting, Penny F; Kleijnen, Jos

    2005-01-01

    Background The use of systematic literature review to inform evidence based practice in diagnostics is rapidly expanding. Although the primary diagnostic literature is extensive, studies are often of low methodological quality or poorly reported. There has been no rigorously evaluated, evidence based tool to assess the methodological quality of diagnostic studies. The primary objective of this study was to determine the extent to which variations in the quality of primary studies impact the results of a diagnostic meta-analysis and whether this differs with diagnostic test type. A secondary objective was to contribute to the evaluation of QUADAS, an evidence-based tool for the assessment of quality in diagnostic accuracy studies. Methods This study was conducted as part of large systematic review of tests used in the diagnosis and further investigation of urinary tract infection (UTI) in children. All studies included in this review were assessed using QUADAS, an evidence-based tool for the assessment of quality in systematic reviews of diagnostic accuracy studies. The impact of individual components of QUADAS on a summary measure of diagnostic accuracy was investigated using regression analysis. The review divided the diagnosis and further investigation of UTI into the following three clinical stages: diagnosis of UTI, localisation of infection, and further investigation of the UTI. Each stage used different types of diagnostic test, which were considered to involve different quality concerns. Results Many of the studies included in our review were poorly reported. The proportion of QUADAS items fulfilled was similar for studies in different sections of the review. However, as might be expected, the individual items fulfilled differed between the three clinical stages. Regression analysis found that different items showed a strong association with test performance for the different tests evaluated. These differences were observed both within and between the three

  6. Accuracy of administrative data for surveillance of healthcare-associated infections: a systematic review

    PubMed Central

    van Mourik, Maaike S M; van Duijn, Pleun Joppe; Moons, Karel G M; Bonten, Marc J M; Lee, Grace M

    2015-01-01

    Objective Measuring the incidence of healthcare-associated infections (HAI) is of increasing importance in current healthcare delivery systems. Administrative data algorithms, including (combinations of) diagnosis codes, are commonly used to determine the occurrence of HAI, either to support within-hospital surveillance programmes or as free-standing quality indicators. We conducted a systematic review evaluating the diagnostic accuracy of administrative data for the detection of HAI. Methods Systematic search of Medline, Embase, CINAHL and Cochrane for relevant studies (1995–2013). Methodological quality assessment was performed using QUADAS-2 criteria; diagnostic accuracy estimates were stratified by HAI type and key study characteristics. Results 57 studies were included, the majority aiming to detect surgical site or bloodstream infections. Study designs were very diverse regarding the specification of their administrative data algorithm (code selections, follow-up) and definitions of HAI presence. One-third of studies had important methodological limitations including differential or incomplete HAI ascertainment or lack of blinding of assessors. Observed sensitivity and positive predictive values of administrative data algorithms for HAI detection were very heterogeneous and generally modest at best, both for within-hospital algorithms and for formal quality indicators; accuracy was particularly poor for the identification of device-associated HAI such as central line associated bloodstream infections. The large heterogeneity in study designs across the included studies precluded formal calculation of summary diagnostic accuracy estimates in most instances. Conclusions Administrative data had limited and highly variable accuracy for the detection of HAI, and their judicious use for internal surveillance efforts and external quality assessment is recommended. If hospitals and policymakers choose to rely on administrative data for HAI surveillance, continued

  7. Accuracy of clinical tests in the diagnosis of anterior cruciate ligament injury: a systematic review.

    PubMed

    Swain, Michael S; Henschke, Nicholas; Kamper, Steven J; Downie, Aron S; Koes, Bart W; Maher, Chris G

    2014-01-01

    Numerous clinical tests are used in the diagnosis of anterior cruciate ligament (ACL) injury but their accuracy is unclear. The purpose of this study is to evaluate the diagnostic accuracy of clinical tests for the diagnosis of ACL injury. Systematic review. The review protocol was registered through PROSPERO (CRD42012002069). Electronic databases (PubMed, MEDLINE, EMBASE, CINAHL) were searched up to 19th of June 2013 to identify diagnostic studies comparing the accuracy of clinical tests for ACL injury to an acceptable reference standard (arthroscopy, arthrotomy, or MRI). Risk of bias was appraised using the QUADAS-2 checklist. Index test accuracy was evaluated using a descriptive analysis of paired likelihood ratios and displayed as forest plots. A total of 285 full-text articles were assessed for eligibility, from which 14 studies were included in this review. Included studies were deemed to be clinically and statistically heterogeneous, so a meta-analysis was not performed. Nine clinical tests from the history (popping sound at time of injury, giving way, effusion, pain, ability to continue activity) and four from physical examination (anterior draw test, Lachman's test, prone Lachman's test and pivot shift test) were investigated for diagnostic accuracy. Inspection of positive and negative likelihood ratios indicated that none of the individual tests provide useful diagnostic information in a clinical setting. Most studies were at risk of bias and reported imprecise estimates of diagnostic accuracy. Despite being widely used and accepted in clinical practice, the results of individual history items or physical tests do not meaningfully change the probability of ACL injury. In contrast combinations of tests have higher diagnostic accuracy; however the most accurate combination of clinical tests remains an area for future research. Clinicians should be aware of the limitations associated with the use of clinical tests for diagnosis of ACL injury.

  8. Accuracy of biochemical markers for predicting nasogastric tube placement in adults--a systematic review of diagnostic studies.

    PubMed

    Fernandez, Ritin S; Chau, Janita Pak-Chun; Thompson, David R; Griffiths, Rhonda; Lo, Hoi-Shan

    2010-08-01

    The objective of this study was to investigate the diagnostic performance of biochemical tests used to determine placement of nasogastric (NG) tubes after insertion in adults. A systematic review of diagnostic studies was undertaken. A literature search of the bibliographic databases and the World Wide Web was performed to locate original diagnostic studies in English or Chinese on biochemical markers for detecting NG tube location. Studies in which one or more different tests were evaluated with a reference standard, and diagnostic values were reported or could be calculated were included. Two reviewers independently checked all abstracts and full text studies for inclusion criteria. Included studies were assessed for their quality using the QUADAS tool. Study features and diagnostic values were extracted from the included studies. Of the 10 studies included in this review, seven investigated the diagnostic accuracy of pH, one investigated the diagnostic accuracy of pH and bilirubin respectively, two a combination of pH and bilirubin and one a combination of pH, pepsin and trypsin levels in identifying NG tube location. All studies used X-rays as the reference standard for comparison. Pooled results demonstrated that a pH of studies and small sample sizes, conclusions about the diagnostic performance of the different tests cannot be drawn. Better designed studies exploring the accuracy of diagnostic tests are needed to improve

  9. Diagnostic Accuracy of Molecular Amplification Tests for Human African Trypanosomiasis—Systematic Review

    PubMed Central

    Boer, Kimberly R.; Dyserinck, Heleen C.; Büscher, Philippe; Schallig, Henk D. H. F.; Leeflang, Mariska M. G.

    2012-01-01

    Background A range of molecular amplification techniques have been developed for the diagnosis of Human African Trypanosomiasis (HAT); however, careful evaluation of these tests must precede implementation to ensure their high clinical accuracy. Here, we investigated the diagnostic accuracy of molecular amplification tests for HAT, the quality of articles and reasons for variation in accuracy. Methodology Data from studies assessing diagnostic molecular amplification tests were extracted and pooled to calculate accuracy. Articles were included if they reported sensitivity and specificity or data whereby values could be calculated. Study quality was assessed using QUADAS and selected studies were analysed using the bivariate random effects model. Results 16 articles evaluating molecular amplification tests fulfilled the inclusion criteria: PCR (n = 12), NASBA (n = 2), LAMP (n = 1) and a study comparing PCR and NASBA (n = 1). Fourteen articles, including 19 different studies were included in the meta-analysis. Summary sensitivity for PCR on blood was 99.0% (95% CI 92.8 to 99.9) and the specificity was 97.7% (95% CI 93.0 to 99.3). Differences in study design and readout method did not significantly change estimates although use of satellite DNA as a target significantly lowers specificity. Sensitivity and specificity of PCR on CSF for staging varied from 87.6% to 100%, and 55.6% to 82.9% respectively. Conclusion Here, PCR seems to have sufficient accuracy to replace microscopy where facilities allow, although this conclusion is based on multiple reference standards and a patient population that was not always representative. Future studies should, therefore, include patients for which PCR may become the test of choice and consider well designed diagnostic accuracy studies to provide extra evidence on the value of PCR in practice. Another use of PCR for control of disease could be to screen samples collected from rural areas and test in reference

  10. Diagnostic accuracy of molecular amplification tests for human African trypanosomiasis--systematic review.

    PubMed

    Mugasa, Claire M; Adams, Emily R; Boer, Kimberly R; Dyserinck, Heleen C; Büscher, Philippe; Schallig, Henk D H F; Leeflang, Mariska M G

    2012-01-01

    A range of molecular amplification techniques have been developed for the diagnosis of Human African Trypanosomiasis (HAT); however, careful evaluation of these tests must precede implementation to ensure their high clinical accuracy. Here, we investigated the diagnostic accuracy of molecular amplification tests for HAT, the quality of articles and reasons for variation in accuracy. Data from studies assessing diagnostic molecular amplification tests were extracted and pooled to calculate accuracy. Articles were included if they reported sensitivity and specificity or data whereby values could be calculated. Study quality was assessed using QUADAS and selected studies were analysed using the bivariate random effects model. 16 articles evaluating molecular amplification tests fulfilled the inclusion criteria: PCR (n = 12), NASBA (n = 2), LAMP (n = 1) and a study comparing PCR and NASBA (n = 1). Fourteen articles, including 19 different studies were included in the meta-analysis. Summary sensitivity for PCR on blood was 99.0% (95% CI 92.8 to 99.9) and the specificity was 97.7% (95% CI 93.0 to 99.3). Differences in study design and readout method did not significantly change estimates although use of satellite DNA as a target significantly lowers specificity. Sensitivity and specificity of PCR on CSF for staging varied from 87.6% to 100%, and 55.6% to 82.9% respectively. Here, PCR seems to have sufficient accuracy to replace microscopy where facilities allow, although this conclusion is based on multiple reference standards and a patient population that was not always representative. Future studies should, therefore, include patients for which PCR may become the test of choice and consider well designed diagnostic accuracy studies to provide extra evidence on the value of PCR in practice. Another use of PCR for control of disease could be to screen samples collected from rural areas and test in reference laboratories, to spot epidemics quickly and

  11. Accuracy of the Alberta Infant Motor Scale (AIMS) to detect developmental delay of gross motor skills in preterm infants: a systematic review.

    PubMed

    de Albuquerque, Plínio Luna; Lemos, Andrea; Guerra, Miriam Queiroz de Farias; Eickmann, Sophie Helena

    2015-02-01

    To assess, through a systematic review, the ability of Alberta Infant Motor Scale (AIMS) to diagnose delayed motor development in preterm infants. Systematic searches identified five studies meeting inclusion criteria. These studies were evaluated in terms of: participants' characteristics, main results and risk of bias. The risk of bias was assessed with the Quality Assessment of Diagnostic Accuracy Studies--second edition (QUADAS-2). All five studies included a high risk of bias in at least one of the assessed fields. The most frequent biases included were presented in patient selection and lost follow up. All studies used the Pearson correlation coefficient to assess the diagnostic capability of the Alberta Infant Motor Scale. None of the assessed studies used psychometric measures to analyze the data. Given the evidence, the research supporting the ability of Alberta Infant Motor Scale to diagnose delayed motor development in preterm infants presents limitations. Further studies are suggested in order to avoid the above-mentioned biases to assess the Alberta Infant Motor Scale accuracy in preterm babies.

  12. Test Accuracy of Informant-Based Cognitive Screening Tests for Diagnosis of Dementia and Multidomain Cognitive Impairment in Stroke.

    PubMed

    McGovern, Aine; Pendlebury, Sarah T; Mishra, Nishant K; Fan, Yuhua; Quinn, Terence J

    2016-02-01

    Poststroke cognitive assessment can be performed using standardized questionnaires designed for family or care givers. We sought to describe the test accuracy of such informant-based assessments for diagnosis of dementia/multidomain cognitive impairment in stroke. We performed a systematic review using a sensitive search strategy across multidisciplinary electronic databases. We created summary test accuracy metrics and described reporting and quality using STARDdem and Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tools, respectively. From 1432 titles, we included 11 studies. Ten papers used the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Four studies described IQCODE for diagnosis of poststroke dementia (n=1197); summary sensitivity: 0.81 (95% confidence interval, 0.60-0.93); summary specificty: 0.83 (95% confidence interval, 0.64-0.93). Five studies described IQCODE as tool for predicting future dementia (n=837); summary sensitivity: 0.60 (95% confidence interval, 0.32-0.83); summary specificity: 0.97 (95% confidence interval, 0.70-1.00). All papers had issues with at least 1 aspect of study reporting or quality. There is a limited literature on informant cognitive assessments in stroke. IQCODE as a diagnostic tool has test properties similar to other screening tools, IQCODE as a prognostic tool is specific but insensitive. We found no papers describing test accuracy of informant tests for diagnosis of prestroke cognitive decline, few papers on poststroke dementia and all included papers had issues with potential bias. © 2015 American Heart Association, Inc.

  13. Accuracy of clinical tests in the diagnosis of anterior cruciate ligament injury: a systematic review

    PubMed Central

    2014-01-01

    Background Numerous clinical tests are used in the diagnosis of anterior cruciate ligament (ACL) injury but their accuracy is unclear. The purpose of this study is to evaluate the diagnostic accuracy of clinical tests for the diagnosis of ACL injury. Methods Study Design: Systematic review. The review protocol was registered through PROSPERO (CRD42012002069). Electronic databases (PubMed, MEDLINE, EMBASE, CINAHL) were searched up to 19th of June 2013 to identify diagnostic studies comparing the accuracy of clinical tests for ACL injury to an acceptable reference standard (arthroscopy, arthrotomy, or MRI). Risk of bias was appraised using the QUADAS-2 checklist. Index test accuracy was evaluated using a descriptive analysis of paired likelihood ratios and displayed as forest plots. Results A total of 285 full-text articles were assessed for eligibility, from which 14 studies were included in this review. Included studies were deemed to be clinically and statistically heterogeneous, so a meta-analysis was not performed. Nine clinical tests from the history (popping sound at time of injury, giving way, effusion, pain, ability to continue activity) and four from physical examination (anterior draw test, Lachman’s test, prone Lachman’s test and pivot shift test) were investigated for diagnostic accuracy. Inspection of positive and negative likelihood ratios indicated that none of the individual tests provide useful diagnostic information in a clinical setting. Most studies were at risk of bias and reported imprecise estimates of diagnostic accuracy. Conclusion Despite being widely used and accepted in clinical practice, the results of individual history items or physical tests do not meaningfully change the probability of ACL injury. In contrast combinations of tests have higher diagnostic accuracy; however the most accurate combination of clinical tests remains an area for future research. Clinical relevance Clinicians should be aware of the limitations associated

  14. Which cuff should I use? Indirect blood pressure measurement for the diagnosis of hypertension in patients with obesity: a diagnostic accuracy review

    PubMed Central

    Holden, John

    2016-01-01

    Objective To determine the diagnostic accuracy of different methods of blood pressure (BP) measurement compared with reference standards for the diagnosis of hypertension in patients with obesity with a large arm circumference. Design Systematic review with meta-analysis with hierarchical summary receiver operating characteristic models. Bland-Altman analyses where individual patient data were available. Methodological quality appraised using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS2) criteria. Data sources MEDLINE, EMBASE, Cochrane, DARE, Medion and Trip databases were searched. Eligibility criteria Cross-sectional, randomised and cohort studies of diagnostic test accuracy that compared any non-invasive BP tests (upper arm, forearm, wrist, finger) with an appropriate reference standard (invasive BP, correctly fitting upper arm cuff, ambulatory BP monitoring) in primary care were included. Results 4037 potentially relevant papers were identified. 20 studies involving 26 different comparisons met the inclusion criteria. Individual patient data were available from 4 studies. No studies satisfied all QUADAS2 criteria. Compared with the reference test of invasive BP, a correctly fitting upper arm BP cuff had a sensitivity of 0.87 (0.79 to 0.93) and a specificity of 0.85 (0.64 to 0.95); insufficient evidence was available for other comparisons to invasive BP. Compared with the reference test of a correctly fitting upper arm cuff, BP measurement at the wrist had a sensitivity of 0.92 (0.64 to 0.99) and a specificity of 0.92 (0.85 to 0.87). Measurement with an incorrectly fitting standard cuff had a sensitivity of 0.73 (0.67 to 0.78) and a specificity of 0.76 (0.69 to 0.82). Measurement at the forearm had a sensitivity of 0.84 (0.71 to 0.92) and a specificity 0.75 of (0.66 to 0.83). Bland-Altman analysis of individual patient data from 3 studies comparing wrist and upper arm BP showed a mean difference of 0.46 mm Hg for systolic BP measurement and 2

  15. Diagnostic accuracy of contrast enhanced ultrasound in patients with blunt abdominal trauma presenting to the emergency department: a systematic review and meta-analysis.

    PubMed

    Zhang, Zhongheng; Hong, Yucai; Liu, Ning; Chen, Yuhao

    2017-06-30

    We aimed to investigate the diagnostic accuracy of contrast-enhanced ultrasound (CEUS) in evaluating blunt abdominal trauma for patients presenting to the emergency department. Electronic search of Scopus and Pubmed was performed from inception to September 2016. Human studies investigating the diagnostic accuracy of CEUS in identifying abdominal solid organ injuries were included. Risk of bias was assessed using the QUADAS tool. A total of 10 studies were included in the study and 9 of them were included for meta-analysis. The log(DOR) values ranged from 3.80 (95% CI: 2.81-4.79) to 8.52 (95% CI: 4.58-12.47) in component studies. The combined log(DOR) was 6.56 (95% CI: 5.66-7.45). The Cochran's Q was 11.265 (p = 0.793 with 16 degrees of freedom), and the Higgins' I 2 was 0%. The CEUS had a sensitivity of 0.981 (95% CI: 0.868-0.950) and a false positive rate of 0.018 (95% CI: 0.010-0.032) for identifying parenchymal injuries, with an AUC of 0.984. CEUS performed at emergency department had good diagnostic accuracy in identifying abdominal solid organ injuries. CEUS can be recommended in monitoring solid organ injuries, especially for patients managed with non-operative strategy.

  16. Diagnostic accuracy of HLA-B*57:01 screening for the prediction of abacavir hypersensitivity and clinical utility of the test: a meta-analytic review.

    PubMed

    Cargnin, Sarah; Jommi, Claudio; Canonico, Pier Luigi; Genazzani, Armando A; Terrazzino, Salvatore

    2014-05-01

    To determine diagnostic accuracy of HLA-B*57:01 testing for prediction of abacavir-induced hypersensitivity and to quantify the clinical benefit of pretreatment screening through a meta-analytic review of published studies. A comprehensive search was performed up to June 2013. The methodological quality of relevant studies was assessed by the QUADAS-2 tool. The pooled diagnostic estimates were calculated using a random effect model. Despite the presence of heterogeneity in sensitivity or specificity estimates, the pooled diagnostic odds ratio to detect abacavir-induced hypersensitivity on the basis of clinical criteria was 33.07 (95% CI: 22.33-48.97, I(2): 13.9%), while diagnostic odds ratio for detection of immunologically confirmed abacavir hypersensitivity was 1141 (95% CI: 409-3181, I(2): 0%). Pooled analysis of risk ratio showed that prospective HLA-B*57:01 testing significantly reduced the incidence of abacavir-induced hypersensitivity. This meta-analysis demonstrates an excellent diagnostic accuracy of HLA-B*57:01 testing to detect immunologically confirmed abacavir hypersensitivity and corroborates existing recommendations.

  17. Accuracy of Nutritional Screening Tools in Assessing the Risk of Undernutrition in Hospitalized Children.

    PubMed

    Huysentruyt, Koen; Devreker, Thierry; Dejonckheere, Joachim; De Schepper, Jean; Vandenplas, Yvan; Cools, Filip

    2015-08-01

    The aim of the present study was to evaluate the predictive accuracy of screening tools for assessing nutritional risk in hospitalized children in developed countries. The study involved a systematic review of literature (MEDLINE, EMBASE, and Cochrane Central databases up to January 17, 2014) of studies on the diagnostic performance of pediatric nutritional screening tools. Methodological quality was assessed using a modified QUADAS tool. Sensitivity and specificity were calculated for each screening tool per validation method. A meta-analysis was performed to estimate the risk ratio of different screening result categories of being truly at nutritional risk. A total of 11 studies were included on ≥1 of the following screening tools: Pediatric Nutritional Risk Score, Screening Tool for the Assessment of Malnutrition in Paediatrics, Paediatric Yorkhill Malnutrition Score, and Screening Tool for Risk on Nutritional Status and Growth. Because of variation in reference standards, a direct comparison of the predictive accuracy of the screening tools was not possible. A meta-analysis was performed on 1629 children from 7 different studies. The risk ratio of being truly at nutritional risk was 0.349 (95% confidence interval [CI] 0.16-0.78) for children in the low versus moderate screening category and 0.292 (95% CI 0.19-0.44) in the moderate versus high screening category. There is insufficient evidence to choose 1 nutritional screening tool over another based on their predictive accuracy. The estimated risk of being at "true nutritional risk" increases with each category of screening test result. Each screening category should be linked to a specific course of action, although further research is needed.

  18. Accuracy of diagnostic imaging modalities for peripheral post-traumatic osteomyelitis - a systematic review of the recent literature.

    PubMed

    Govaert, Geertje A; IJpma, Frank F; McNally, Martin; McNally, Eugene; Reininga, Inge H; Glaudemans, Andor W

    2017-08-01

    Post-traumatic osteomyelitis (PTO) is difficult to diagnose and there is no consensus on the best imaging strategy. The aim of this study is to present a systematic review of the recent literature on diagnostic imaging of PTO. A literature search of the EMBASE and PubMed databases of the last 16 years (2000-2016) was performed. Studies that evaluated the accuracy of magnetic resonance imaging (MRI), three-phase bone scintigraphy (TPBS), white blood cell (WBC) or antigranulocyte antibody (AGA) scintigraphy, fluorodeoxyglucose positron emission tomography (FDG-PET) and plain computed tomography (CT) in diagnosing PTO were considered for inclusion. The review was conducted using the PRISMA statement and QUADAS-2 criteria. The literature search identified 3358 original records, of which 10 articles could be included in this review. Four of these studies had a comparative design which made it possible to report the results of, in total, 17 patient series. WBC (or AGA) scintigraphy and FDG-PET exhibit good accuracy for diagnosing PTO (sensitivity ranged from 50-100%, specificity ranged from 40-97% versus 83-100% and 51%-100%, respectively). The accuracy of both modalities improved when a hybrid imaging technique (SPECT/CT & FDG-PET/CT) was performed. For FDG-PET/CT, sensitivity ranged between 86 and 94% and specificity between 76 and 100%. For WBC scintigraphy + SPECT/CT, this is 100% and 89-97%, respectively. Based on the best available evidence of the last 16 years, both WBC (or AGA) scintigraphy combined with SPECT/CT or FDG-PET combined with CT have the best diagnostic accuracy for diagnosing peripheral PTO.

  19. Magnetic resonance imaging for detecting root avulsions in traumatic adult brachial plexus injuries: protocol for a systematic review of diagnostic accuracy.

    PubMed

    Wade, Ryckie G; Takwoingi, Yemisi; Wormald, Justin C R; Ridgway, John P; Tanner, Steven; Rankine, James J; Bourke, Grainne

    2018-05-19

    Adult brachial plexus injuries (BPI) are becoming more common. The reconstruction and prognosis of pre-ganglionic injuries (root avulsions) are different to other types of BPI injury. Preoperative magnetic resonance imaging (MRI) is being used to identify root avulsions, but the evidence from studies of its diagnostic accuracy are conflicting. Therefore, a systematic review is needed to address uncertainty about the accuracy of MRI and to guide future research. We will conduct a systematic search of electronic databases alongside reference tracking. We will include studies of adults with traumatic BPI which report the accuracy of preoperative MRI (index test) against surgical exploration of the roots of the brachial plexus (reference standard) for detecting either of the two target conditions (any root avulsion or any pseudomeningocoele as a surrogate marker of root avulsion). We will exclude case reports, articles considering bilateral injuries and studies where the number of true positives, false positives, false negatives and true negatives cannot be derived. The methodological quality of the included studies will be assessed using a tailored version of the QUADAS-2 tool. Where possible, a bivariate model will be used for meta-analysis to obtain summary sensitivities and specificities for both target conditions. We will investigate heterogeneity in the performance of MRI according to field strength and the risk of bias if data permits. This review will summarise the current diagnostic accuracy of MRI for adult BPI, identify shortcomings and gaps in the literature and so help to guide future research. PROSPERO CRD42016049702 .

  20. Which cuff should I use? Indirect blood pressure measurement for the diagnosis of hypertension in patients with obesity: a diagnostic accuracy review.

    PubMed

    Irving, Greg; Holden, John; Stevens, Richard; McManus, Richard J

    2016-11-03

    To determine the diagnostic accuracy of different methods of blood pressure (BP) measurement compared with reference standards for the diagnosis of hypertension in patients with obesity with a large arm circumference. Systematic review with meta-analysis with hierarchical summary receiver operating characteristic models. Bland-Altman analyses where individual patient data were available. Methodological quality appraised using Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS2) criteria. MEDLINE, EMBASE, Cochrane, DARE, Medion and Trip databases were searched. Cross-sectional, randomised and cohort studies of diagnostic test accuracy that compared any non-invasive BP tests (upper arm, forearm, wrist, finger) with an appropriate reference standard (invasive BP, correctly fitting upper arm cuff, ambulatory BP monitoring) in primary care were included. 4037 potentially relevant papers were identified. 20 studies involving 26 different comparisons met the inclusion criteria. Individual patient data were available from 4 studies. No studies satisfied all QUADAS2 criteria. Compared with the reference test of invasive BP, a correctly fitting upper arm BP cuff had a sensitivity of 0.87 (0.79 to 0.93) and a specificity of 0.85 (0.64 to 0.95); insufficient evidence was available for other comparisons to invasive BP. Compared with the reference test of a correctly fitting upper arm cuff, BP measurement at the wrist had a sensitivity of 0.92 (0.64 to 0.99) and a specificity of 0.92 (0.85 to 0.87). Measurement with an incorrectly fitting standard cuff had a sensitivity of 0.73 (0.67 to 0.78) and a specificity of 0.76 (0.69 to 0.82). Measurement at the forearm had a sensitivity of 0.84 (0.71 to 0.92) and a specificity 0.75 of (0.66 to 0.83). Bland-Altman analysis of individual patient data from 3 studies comparing wrist and upper arm BP showed a mean difference of 0.46 mm Hg for systolic BP measurement and 2.2 mm Hg for diastolic BP measurement. BP measurement

  1. Diagnostic accuracy, risk assessment, and cost-effectiveness of component-resolved diagnostics for food allergy: A systematic review.

    PubMed

    Flores Kim, J; McCleary, N; Nwaru, B I; Stoddart, A; Sheikh, A

    2018-01-10

    Component-resolved diagnostics (CRD) are promising tools for diagnosing food allergy, offering the potential to determine specific phenotypes and to develop patient-tailored risk profiles. Nevertheless, the diagnostic accuracy of these tests varies across studies; thus, their clinical utility remains unclear. Therefore, we synthesized the evidence from studies investigating the diagnostic accuracy, risk assessment ability, and cost-effectiveness of CRD for food allergy. We systematically searched 10 electronic databases and four clinical trial registries for studies published from January 2000 to February 2017. The quality of included studies was assessed using QUADAS-2. Due to heterogeneity, we narratively synthesized the evidence. Eleven studies met inclusion criteria, altogether recruiting 1098 participants. The food allergies investigated were cow's milk, hen's egg, peanut, hazelnut, and shrimp. The components with the highest diagnostic accuracy for each allergen, along with their sensitivity-specificity pairs, were as follows: Bos d 4 for cow's milk (62.0% and 87.5%), Gal d 1 for hen's egg (84.2% and 89.8% for heated egg, and 60.6% and 97.1% for raw egg), Ara h 6 for peanut (94.9% and 95.1%), Cor a 14 for hazelnut (100% and 93.8%), and Lit v 1 for shrimp (82.8% and 56.3%) allergy. Selected components of cow's milk, hen's egg, peanut, hazelnut, and shrimp allergen showed high specificity, but lower sensitivity. However, few studies exist for each component, and studies vary widely regarding the cutoff values used, making it challenging to synthesize findings across studies. Further research is needed to determine clinically appropriate cutoff values, risk assessment abilities, and cost-effectiveness of CRD approaches. © 2018 The Authors. Allergy Published by John Wiley & Sons Ltd.

  2. Performance of alternative strategies for primary cervical cancer screening in sub-Saharan Africa: systematic review and meta-analysis of diagnostic test accuracy studies

    PubMed Central

    Combescure, Christophe; Fokom-Defo, Victoire; Tebeu, Pierre Marie; Vassilakos, Pierre; Kengne, André Pascal; Petignat, Patrick

    2015-01-01

    Objective To assess and compare the accuracy of visual inspection with acetic acid (VIA), visual inspection with Lugol’s iodine (VILI), and human papillomavirus (HPV) testing as alternative standalone methods for primary cervical cancer screening in sub-Saharan Africa. Design Systematic review and meta-analysis of diagnostic test accuracy studies. Data sources Systematic searches of multiple databases including Medline, Embase, and Scopus for studies published between January 1994 and June 2014. Review methods Inclusion criteria for studies were: alternative methods to cytology used as a standalone test for primary screening; study population not at particular risk of cervical cancer (excluding studies focusing on HIV positive women or women with gynaecological symptoms); women screened by nurses; reference test (colposcopy and directed biopsies) performed at least in women with positive screening results. Two reviewers independently screened studies for eligibility and extracted data for inclusion, and evaluated study quality using the quality assessment of diagnostic accuracy studies 2 (QUADAS-2) checklist. Primary outcomes were absolute accuracy measures (sensitivity and specificity) of screening tests to detect cervical intraepithelial neoplasia grade 2 or worse (CIN2+). Results 15 studies of moderate quality were included (n=61 381 for VIA, n=46 435 for VILI, n=11 322 for HPV testing). Prevalence of CIN2+ did not vary by screening test and ranged from 2.3% (95% confidence interval 1.5% to 3.3%) in VILI studies to 4.9% (2.7% to 7.8%) in HPV testing studies. Positivity rates of VILI, VIA, and HPV testing were 16.5% (9.8% to 24.7%), 16.8% (11.0% to 23.6%), and 25.8% (17.4% to 35.3%), respectively. Pooled sensitivity was higher for VILI (95.1%; 90.1% to 97.7%) than VIA (82.4%; 76.3% to 87.3%) in studies where the reference test was performed in all women (P<0.001). Pooled specificity of VILI and VIA were similar (87.2% (78.1% to 92.8%) v 87.4% (77.1% to 93

  3. Diagnostic accuracy of the 14C-urea breath test in Helicobacter pylori infections: a meta-analysis.

    PubMed

    Zhou, Qiaohui; Li, Ling; Ai, Yaowei; Pan, Zhihong; Guo, Mingwen; Han, Jingbo

    2017-01-01

    To summarize and appraise the available literature regarding the use of the 14 C-urea breath test in the diagnosis of Helicobacter pylori infections in adult patients with dyspepsia and to calculate pooled diagnostic accuracy measures. We systematically searched the PubMed, EMBASE, Cochrane Library, Chinese Journals Full-text (CNKI) and CBMDisc databases to identify published data regarding the sensitivity, specificity, and other measures of diagnostic accuracy of the 14 C-urea breath test in the diagnosis of Helicobacter pylori infections in adult patients with dyspeptic symptoms. Risk of bias was assessed using the QUADAS (Quality Assessment of Diagnostic Accuracy Studies)-2 tool. Statistical analyses were performed using Meta-Disc 1.4 software and STATA. Eighteen studies met the inclusion criteria. Pooled results indicated that the  14 C-urea breath test showed a diagnostic sensitivity of 0.96 (95% CI 0.95 to 0.96) and specificity of 0.93 (95% CI 0.91 to 0.94). The positive like ratio (PLR) was 12.27 (95% CI 8.17 to 18.44), the negative like ratio (NLR) was 0.05 (95% CI 0.04 to 0.07), and the area under the curve was 0.985. The DOR was 294.95 (95% CI 178.37 to 487.70). The 14 C-urea breath test showed sufficient sensitivity and specificity for diagnosing Helicobacter pylori infection, but unexplained heterogeneity after meta-regression and several subgroup analyses remained. The UBT has high accuracy for diagnosing H. pylori infections in adult patients with dyspepsia. However, the reliability of these diagnostic meta-analytic estimates is limited by significant heterogeneity due to unknown factors.

  4. PAX1 Methylation Hallmarks Promising Accuracy for Cervical Cancer Screening in Asians: Results from a Meta-Analysis.

    PubMed

    Kong, Ling-Ying; Du, Wei; Wang, Li; Yang, Zhi; Zhang, Hong-Sheng

    2015-01-01

    DNA methylation has been proposed as a potential biomarker for cervical cancer detection. This study aimed to evaluate the diagnostic role of paired boxed gene 1 (PAX1) methylation for cervical cancer screening in Asians. Eligible studies were retrieved by searching the electronic databases, and the quality of the enrolled studies was assessed via the quality assessment for studies of diagnostic accuracy (QUADAS) tool. The bivariate meta-analysis model was employed to generate the summary receiver operator characteristic (SROC) curve using Stata 12.0 software. Cochran's Q test and I2 statistics were applied to assess heterogeneity among studies. Publication bias was evaluated by the Deeks' funnel plot asymmetry test. A total of 9 articles containing 15 individual studies were included. The SROC analysis showed that single PAX1 methylation allowed for the discrimination between cancer/high-grade squamous intraepithelial lesion (HSIL) patients and normal individuals with a sensitivity (95% confidence interval) of 0.80 (0.70 - 0.87) and specificity of 0.89 (0.86 - 0.92), corresponding to an area under curve (AUC) of 0.92. Notably, our subgroup analysis suggested that combing parallel testing of PAX1 methylation and HPV DNA (AUC, sensitivity, and specificity of 0.90, 0.82, and 0.84, respectively) seemed to harbor higher accuracy than single HPV DNA testing (AUC, sensitivity, and specificity of 0.81, 0.86, and 0.67, respectively). PAX1 methylation hallmarks a potential diagnostic value for cervical cancer screening in Asians, and parallel testing of PAX1 methylation and HPV in cervical scrapings confers an improved accuracy than single HPV DNA testing.

  5. Accuracy of cystatin C for the detection of abnormal renal function in children undergoing chemotherapy for malignancy: a systematic review using individual patient data.

    PubMed

    Whiting, Penny; Birnie, Kate; Sterne, Jonathan A C; Jameson, Catherine; Skinner, Rod; Phillips, Bob

    2018-05-01

    We conducted a systematic review and individual patient data (IPD) meta-analysis to examine the utility of cystatin C for evaluation of glomerular function in children with cancer. Eligible studies evaluated the accuracy of cystatin C for detecting poor renal function in children undergoing chemotherapy. Study quality was assessed using QUADAS-2. Authors of four studies shared IPD. We calculated the correlation between log cystatin C and GFR stratified by study and measure of cystatin C. We dichotomized the reference standard at GFR 80 ml/min/1.73m 2 and stratified cystatin C at 1 mg/l, to calculate sensitivity and specificity in each study and according to age group (0-4, 5-12, and ≥ 13 years). In sensitivity analyses, we investigated different GFR and cystatin C cut points. We used logistic regression to estimate the association of impaired renal function with log cystatin C and quantified diagnostic accuracy using the area under the ROC curve (AUC). Six studies, which used different test and reference standard thresholds, suggested that cystatin C has the potential to monitor renal function in children undergoing chemotherapy for malignancy. IPD data (504 samples, 209 children) showed that cystatin C has poor sensitivity (63%) and moderate specificity (89%), although use of a GFR cut point of < 60 ml/min/1.73m 2 (data only available from two of the studies) estimated sensitivity to be 92% and specificity 81.3%. The AUC for the combined data set was 0.890 (95% CI 0.826, 0.951). Diagnostic accuracy appeared to decrease with age. Cystatin C has better diagnostic accuracy than creatinine as a test for glomerular dysfunction in young people undergoing treatment for cancer. Diagnostic accuracy is not sufficient for it to replace current reference standards for predicting clinically relevant impairments that may alter dosing of important nephrotoxic agents.

  6. A Systematic Review and Meta-analysis of the Diagnostic Accuracy of Prostate Health Index and 4-Kallikrein Panel Score in Predicting Overall and High-grade Prostate Cancer.

    PubMed

    Russo, Giorgio Ivan; Regis, Federica; Castelli, Tommaso; Favilla, Vincenzo; Privitera, Salvatore; Giardina, Raimondo; Cimino, Sebastiano; Morgia, Giuseppe

    2017-08-01

    Markers for prostate cancer (PCa) have progressed over recent years. In particular, the prostate health index (PHI) and the 4-kallikrein (4K) panel have been demonstrated to improve the diagnosis of PCa. We aimed to review the diagnostic accuracy of PHI and the 4K panel for PCa detection. We performed a systematic literature search of PubMed, EMBASE, Cochrane, and Academic One File databases until July 2016. We included diagnostic accuracy studies that used PHI or 4K panel for the diagnosis of PCa or high-grade PCa. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Twenty-eight studies including 16,762 patients have been included for the analysis. The pooled data showed a sensitivity of 0.89 and 0.74 for PHI and 4K panel, respectively, for PCa detection and a pooled specificity of 0.34 and 0.60 for PHI and 4K panel, respectively. The derived area under the curve (AUC) from the hierarchical summary receiver operating characteristic (HSROC) showed an accuracy of 0.76 and 0.72 for PHI and 4K panel respectively. For high-grade PCa detection, the pooled sensitivity was 0.93 and 0.87 for PHI and 4K panel, respectively, whereas the pooled specificity was 0.34 and 0.61 for PHI and 4K panel, respectively. The derived AUC from the HSROC showed an accuracy of 0.82 and 0.81 for PHI and 4K panel, respectively. Both PHI and the 4K panel provided good diagnostic accuracy in detecting overall and high-grade PCa. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Physical examination tests for the diagnosis of femoroacetabular impingement. A systematic review.

    PubMed

    Pacheco-Carrillo, Aitana; Medina-Porqueres, Ivan

    2016-09-01

    Numerous clinical tests have been proposed to diagnose FAI, but little is known about their diagnostic accuracy. To summarize and evaluate research on the accuracy of physical examination tests for diagnosis of FAI. A search of the PubMed, SPORTDiscus and CINAHL databases was performed. Studies were considered eligible if they compared the results of physical examination tests to those of a reference standard. Methodological quality and internal validity assessment was performed by two independent reviewers using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. The systematic search strategy revealed 298 potential articles, five of which articles met the inclusion criteria. After assessment using the QUADAS score, four of the five articles were of high quality. Clinical tests included were Impingement sign, IROP test (Internal Rotation Over Pressure), FABER test (Flexion-Abduction-External Rotation), Stinchfield/RSRL (Resisted Straight Leg Raise) test, Scour test, Maximal squat test, and the Anterior Impingement test. IROP test, impingement sign, and FABER test showed the most sensitive values to identify FAI. The diagnostic accuracy of physical examination tests to assess FAI is limited due to its heterogenecity. There is a strong need for sound research of high methodological quality in this area. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. F-18 FDG PET, CT, and MRI for detecting the malignant potential in patients with gastrointestinal stromal tumors: A protocol for a network meta-analysis of diagnostic test accuracy.

    PubMed

    Wei, Kongyuan; Pan, Bei; Yang, Huan; Lu, Cuncun; Ge, Long; Cao, Nong

    2018-04-01

    Gastrointestinal stromal tumor (GIST) is a rare cancer in gastrointestinal carcinomas and has been widely known as a curable disease among all the digestive tumors. However, early detection of malignant potential in patients with GIST has still been a huge challenge all around the world. CT, MRI, and F-18 FDG PET are all considered as good tests for diagnosing malignant GIST efficiently, but no recommended suggestions presents which test among the 3 is the prior one in detecting the malignant potential of GIST. We perform this study to assess the accuracy between CT, MRI, and F-18 FDG PET through network meta-analysis method, and to rank these tests. PubMed, EMBASE.com, CNKI, and CBM databases will be searched without search date and language restrictions. We will include diagnostic tests which assessed the accuracy of CT, MRI, and F-18 FDG PET in detecting the malignant potential of GIST. The risk of bias in each study will be independently assessed as low, moderate, or high using criteria adapted from Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Meta-analysis will be performed using STATA 12.0 and R 3.4.1 software. The competing diagnostic tests will be ranked by a superiority index. This study is ongoing, and will be submitted to a peer-reviewed journal for publication. This study will provide a comprehensive evidence summary of CT, MRI, and F-18 FDG PET in detecting the malignant potential of GIST.

  9. Five common tumor biomarkers and CEA for diagnosing early gastric cancer: A protocol for a network meta-analysis of diagnostic test accuracy.

    PubMed

    Shen, Minghui; Wang, Hui; Wei, Kongyuan; Zhang, Jianling; You, Chongge

    2018-05-01

    Although surgical resection is the recommended treatment for the patients with gastric cancer, lots of patients show advanced or metastatic gastric cancer at the time of diagnosis. Detection of gastric cancer at early stages is a huge challenge because of lack of appropriate detection tests. Unfortunately, existing clinical guidelines focusing on early diagnosis of gastric cancer do not provide consistent and prudent evidence. Serum carcinoembryonic antigen was considered as a complementary test, although it is not good enough to diagnose early gastric cancer. There are no other tumor markers recommended for diagnosing early gastric cancer. This study aims to evaluate and compare the diagnostic accuracy of 5 common tumor biomarkers (CA19-9, CA125, PG, IncRNA, and DNA methylation) and CEA and their combinations for diagnosing gastric cancer through network meta-analysis method, and to rank these tests using a superiority index. PubMed, EMBASE.com, and the Cochrane Central Register of Controlled Trials (CENTRAL) will be searched from their inception to March 2018. We will include diagnostic tests which assessed the accuracy of the above-mentioned tumor biomarkers and CEA for diagnosing gastric cancer. The risk of bias for each study will be independently assessed as low, moderate, or high using criteria adapted from Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2). Network meta-analysis will be performed using STATA 12.0 and R 3.4.1 software. The competing diagnostic tests will be ranked by a superiority index. This study is ongoing and will be submitted to a peer-reviewed journal for publication. This study will provide systematically suggestions to select different tumor biomarkers for detecting the early gastric cancer.

  10. Diagnostic accuracy of history, physical examination, and bedside ultrasound for diagnosis of extremity fractures in the emergency department: a systematic review.

    PubMed

    Joshi, Nikita; Lira, Alena; Mehta, Ninfa; Paladino, Lorenzo; Sinert, Richard

    2013-01-01

    Understanding history, physical examination, and ultrasonography (US) to diagnose extremity fractures compared with radiography has potential benefits of decreasing radiation exposure, costs, and pain and improving emergency department (ED) resource management and triage time. The authors performed two electronic searches using PubMed and EMBASE databases for studies published between 1965 to 2012 using a strategy based on the inclusion of any patient presenting with extremity injuries suspicious for fracture who had history and physical examination and a separate search for US performed by an emergency physician (EP) with subsequent radiography. The primary outcome was operating characteristics of ED history, physical examination, and US in diagnosing radiologically proven extremity fractures. The methodologic quality of the studies was assessed using the quality assessment of studies of diagnostic accuracy tool (QUADAS-2). Nine studies met the inclusion criteria for history and physical examination, while eight studies met the inclusion criteria for US. There was significant heterogeneity in the studies that prevented data pooling. Data were organized into subgroups based on anatomic fracture locations, but heterogeneity within the subgroups also prevented data pooling. The prevalence of fracture varied among the studies from 22% to 70%. Upper extremity physical examination tests have positive likelihood ratios (LRs) ranging from 1.2 to infinity and negative LRs ranging from 0 to 0.8. US sensitivities varied between 85% and 100%, specificities varied between 73% and 100%, positive LRs varied between 3.2 and 56.1, and negative LRs varied between 0 and 0.2. Compared with radiography, EP US is an accurate diagnostic test to rule in or rule out extremity fractures. The diagnostic accuracy for history and physical examination are inconclusive. Future research is needed to understand the accuracy of ED US when combined with history and physical examination for upper

  11. Is early detection of abused children possible?: a systematic review of the diagnostic accuracy of the identification of abused children

    PubMed Central

    2013-01-01

    Background Early detection of abused children could help decrease mortality and morbidity related to this major public health problem. Several authors have proposed tools to screen for child maltreatment. The aim of this systematic review was to examine the evidence on accuracy of tools proposed to identify abused children before their death and assess if any were adapted to screening. Methods We searched in PUBMED, PsycINFO, SCOPUS, FRANCIS and PASCAL for studies estimating diagnostic accuracy of tools identifying neglect, or physical, psychological or sexual abuse of children, published in English or French from 1961 to April 2012. We extracted selected information about study design, patient populations, assessment methods, and the accuracy parameters. Study quality was assessed using QUADAS criteria. Results A total of 2 280 articles were identified. Thirteen studies were selected, of which seven dealt with physical abuse, four with sexual abuse, one with emotional abuse, and one with any abuse and physical neglect. Study quality was low, even when not considering the lack of gold standard for detection of abused children. In 11 studies, instruments identified abused children only when they had clinical symptoms. Sensitivity of tests varied between 0.26 (95% confidence interval [0.17-0.36]) and 0.97 [0.84-1], and specificity between 0.51 [0.39-0.63] and 1 [0.95-1]. The sensitivity was greater than 90% only for three tests: the absence of scalp swelling to identify children victims of inflicted head injury; a decision tool to identify physically-abused children among those hospitalized in a Pediatric Intensive Care Unit; and a parental interview integrating twelve child symptoms to identify sexually-abused children. When the sensitivity was high, the specificity was always smaller than 90%. Conclusions In 2012, there is low-quality evidence on the accuracy of instruments for identifying abused children. Identified tools were not adapted to screening because of

  12. Diagnostic accuracy of serological diagnosis of hepatitis C and B using dried blood spot samples (DBS): two systematic reviews and meta-analyses.

    PubMed

    Lange, Berit; Cohn, Jennifer; Roberts, Teri; Camp, Johannes; Chauffour, Jeanne; Gummadi, Nina; Ishizaki, Azumi; Nagarathnam, Anupriya; Tuaillon, Edouard; van de Perre, Philippe; Pichler, Christine; Easterbrook, Philippa; Denkinger, Claudia M

    2017-11-01

    Dried blood spots (DBS) are a convenient tool to enable diagnostic testing for viral diseases due to transport, handling and logistical advantages over conventional venous blood sampling. A better understanding of the performance of serological testing for hepatitis C (HCV) and hepatitis B virus (HBV) from DBS is important to enable more widespread use of this sampling approach in resource limited settings, and to inform the 2017 World Health Organization (WHO) guidance on testing for HBV/HCV. We conducted two systematic reviews and meta-analyses on the diagnostic accuracy of HCV antibody (HCV-Ab) and HBV surface antigen (HBsAg) from DBS samples compared to venous blood samples. MEDLINE, EMBASE, Global Health and Cochrane library were searched for studies that assessed diagnostic accuracy with DBS and agreement between DBS and venous sampling. Heterogeneity of results was assessed and where possible a pooled analysis of sensitivity and specificity was performed using a bivariate analysis with maximum likelihood estimate and 95% confidence intervals (95%CI). We conducted a narrative review on the impact of varying storage conditions or limits of detection in subsets of samples. The QUADAS-2 tool was used to assess risk of bias. For the diagnostic accuracy of HBsAg from DBS compared to venous blood, 19 studies were included in a quantitative meta-analysis, and 23 in a narrative review. Pooled sensitivity and specificity were 98% (95%CI:95%-99%) and 100% (95%CI:99-100%), respectively. For the diagnostic accuracy of HCV-Ab from DBS, 19 studies were included in a pooled quantitative meta-analysis, and 23 studies were included in a narrative review. Pooled estimates of sensitivity and specificity were 98% (CI95%:95-99) and 99% (CI95%:98-100), respectively. Overall quality of studies and heterogeneity were rated as moderate in both systematic reviews. HCV-Ab and HBsAg testing using DBS compared to venous blood sampling was associated with excellent diagnostic accuracy

  13. Accuracy of fundus autofluorescence imaging for the diagnosis and monitoring of retinal conditions: a systematic review.

    PubMed

    Frampton, Geoff K; Kalita, Neelam; Payne, Liz; Colquitt, Jill; Loveman, Emma

    2016-04-01

    Natural fluorescence in the eye may be increased or decreased by diseases that affect the retina. Imaging methods based on confocal scanning laser ophthalmoscopy (cSLO) can detect this 'fundus autofluorescence' (FAF) by illuminating the retina using a specific light 'excitation wavelength'. FAF imaging could assist the diagnosis or monitoring of retinal conditions. However, the accuracy of the method for diagnosis or monitoring is unclear. To conduct a systematic review to determine the accuracy of FAF imaging using cSLO for the diagnosis or monitoring of retinal conditions, including monitoring of response to therapy. Electronic bibliographic databases; scrutiny of reference lists of included studies and relevant systematic reviews; and searches of internet pages of relevant organisations, meetings and trial registries. Databases included MEDLINE, EMBASE, The Cochrane Library, Web of Science and the Medion database of diagnostic accuracy studies. Searches covered 1990 to November 2014 and were limited to the English language. References were screened for relevance using prespecified inclusion criteria to capture a broad range of retinal conditions. Two reviewers assessed titles and abstracts independently. Full-text versions of relevant records were retrieved and screened by one reviewer and checked by a second. Data were extracted and critically appraised using the Quality Assessment of Diagnostic Accuracy Studies criteria (QUADAS) for assessing risk of bias in test accuracy studies by one reviewer and checked by a second. At all stages any reviewer disagreement was resolved through discussion or arbitration by a third reviewer. Eight primary research studies have investigated the diagnostic accuracy of FAF imaging in retinal conditions: choroidal neovascularisation (one study), reticular pseudodrusen (three studies), cystoid macular oedema (two studies) and diabetic macular oedema (two studies). Sensitivity of FAF imaging using an excitation wavelength of 488

  14. Accuracy of Tactile Assessment of Fever in Children by Caregivers: A Systematic Review and Meta-analysis.

    PubMed

    Li, Yan-Wei; Zhou, Le-Shan; Li, Xing

    2017-03-15

    Fever is the most common complaint in the pediatric and emergency departments. Caregivers prefer to detect fever in their children by tactile assessment. To summarize the evidence on the accuracy of caregivers' tactile assessment for detecting fever in children. We performed a literature search of Cochrane Library, PubMed, Web of Knowledge, EMBASE (ovid), EBSCO and Google Scholar, without restriction of publication date, to identify English articles assessing caregivers' ability of detecting fever in children by tactile assessment. Quality assessment was based on the 2011 Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. Pooled estimates of sensitivity and specificity were calculated with use of bivariate model and summary receiver operation characteristics plots for meta-analysis. 11 articles were included in our analysis. The summary estimates for tactile assessment as a diagnostic tool revealed a sensitivity of 87.5% (95% CI 79.3% to 92.8%) and specificity of 54.6% (95% CI 38.5% to 69.9%). The pooled positive likelihood ratio was 1.93 (95% CI 1.39 to 2.67) and negative likelihood ratio was 0.23 (95% CI 0.15 to 0.36). Area under curve was 0.82 (95% CI 0.7 to 0.85). The pooled diagnostic odds ratio was 8.46 (95% CI 4.54 to 15.76). Tactile assessment of fever in children by palpation has moderate diagnostic value. Caregivers' assessment as "no fever" by touch is quite accurate in ruling out fever, while assessment as "fever" can be considered but needs confirmation.

  15. Diagnostic accuracy of nucleic acid amplification based assays for tuberculous meningitis: A meta-analysis.

    PubMed

    Gupta, Renu; Talwar, Puneet; Talwar, Pumanshi; Khurana, Sarbjeet; Kushwaha, Suman; Jalan, Nupur; Thakur, Rajeev

    2018-05-25

    Numerous in-house and commercial nucleic acid amplification tests (NAAT) have been evaluated using variable reference standards for diagnosis of TBM but their diagnostic potential is still not very clear. We conducted a meta-analysis to assess the diagnostic accuracy of different NAAT based assays for diagnosing TBM against 43 data sets of confirmed TBM (n = 1066) and 61 data sets of suspected TBM (n = 3721) as two reference standards. The summary estimate of the sensitivity and the specificity were obtained using the bivariate model. QUADAS-2 tool was used to perform the Quality assessment for bias and applicability. Publication bias was assessed with Deeks' funnel plot. Studies with confirmed TBM had better summary estimates as compared to studies with clinically suspected TBM irrespective of NAAT and index tests used. Among in-house assays, MPB as the gene target had best summary estimates in both confirmed [sensitivity:90%(83-95), specificity:97-%(87-99), DOR:247 (50-1221), AUC:99%(97-100), PLR:38.8-(6.6-133), NLR:0.11(0.05-0.18), I 2   = 15%] and clinically suspected [sensitivity:69%(47-85), specificity:96%(90-98), DOR:62(16.8-232), AUC:94%(92-97), PLR:16.9(6.5-36.8), NLR:0.33(0.16-0.56), I 2 :15.3%] groups. GeneXpert revealed good diagnostic accuracy only in confirmed TBM group [sensitivity = 57%(38-74), specificity = 98%(89-100), DOR = 62(7-589), AUC = 87%(79-96), PLR = 33.2(3.8-128), NLR = 0.45(0.26-0.68), I 2   = 0%]. This meta-analysis identified potential role of MPB gene among in-house assays and GeneXpert as commercial assay for diagnosing TBM. Copyright © 2018. Published by Elsevier Ltd.

  16. A meta-analysis of the diagnostic test accuracy of MRA and MRI for the detection of glenoid labral injury.

    PubMed

    Smith, Toby O; Drew, Benjamin T; Toms, Andoni P

    2012-07-01

    Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) have gained increasing favour in the assessment of patients with suspected glenoid labral injuries. The purpose of this study was to determine the diagnostic accuracy of MRI or MRA in the detection of gleniod labral lesions. A systematic review was undertaken of the electronic databases Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, AMED and CINAHL, in addition to a search of unpublished literature databases. All studies which compared the ability of MRI or MRA (index test) to assess gleniod labral tears or lesions, when verified with a surgical procedure (arthroscopy or open surgery-reference test) were included. Data extraction and methodological appraisal using the QUADAS tool were both conducted by two reviewers independently. Data were analysed through a summary receiver operator characteristic curve and pooled sensitivity and specificity analysis were calculated with 95% confidence intervals. Sixty studies including 4,667 shoulders from 4,574 patients were reviewed. There appeared slightly greater diagnostic test accuracy for MRA over MRI for the detection of overall gleniod labral lesions (MRA-sensitivity 88%, specificity 93% vs. MRI sensitivity 76% vs. specificity 87%). Methodologically, studies recruited and identified their samples appropriately and clearly defined the radiological procedures. In general, it was not clearly defined why patients were lost during the study, and studies were poor at recording whether the same clinical data were available to the radiologist interpreting the MRI or MRA as would be available in clinical practice. Most studies did not state whether the surgeon interpreting the arthroscopic procedure was blinded to the results of the MR or MRA imaging. Based on the available literature, overall MRA appeared marginally superior to MRI for the detection of glenohumeral labral lesions. Level 2a.

  17. Diagnostic accuracy of different caries risk assessment methods. A systematic review.

    PubMed

    Senneby, Anna; Mejàre, Ingegerd; Sahlin, Nils-Eric; Svensäter, Gunnel; Rohlin, Madeleine

    2015-12-01

    To evaluate the accuracy of different methods used to identify individuals with increased risk of developing dental coronal caries. Studies on following methods were included: previous caries experience, tests using microbiota, buffering capacity, salivary flow rate, oral hygiene, dietary habits and sociodemographic variables. QUADAS-2 was used to assess risk of bias. Sensitivity, specificity, predictive values, and likelihood ratios (LR) were calculated. Quality of evidence based on ≥3 studies of a method was rated according to GRADE. PubMed, Cochrane Library, Web of Science and reference lists of included publications were searched up to January 2015. From 5776 identified articles, 18 were included. Assessment of study quality identified methodological limitations concerning study design, test technology and reporting. No study presented low risk of bias in all domains. Three or more studies were found only for previous caries experience and salivary mutans streptococci and quality of evidence for these methods was low. Evidence regarding other methods was lacking. For previous caries experience, sensitivity ranged between 0.21 and 0.94 and specificity between 0.20 and 1. Tests using salivary mutans streptococci resulted in low sensitivity and high specificity. For children with primary teeth at baseline, pooled LR for a positive test was 3 for previous caries experience and 4 for salivary mutans streptococci, given a threshold ≥10(5) CFU/ml. Evidence on the validity of analysed methods used for caries risk assessment is limited. As methodological quality was low, there is a need to improve study design. Low validity for the analysed methods may lead to patients with increased risk not being identified, whereas some are falsely identified as being at risk. As caries risk assessment guides individualized decisions on interventions and intervals for patient recall, improved performance based on best evidence is greatly needed. Copyright © 2015 Elsevier Ltd

  18. Accuracy of the third molar maturity index in assessing the legal age of 18 years: a systematic review and meta-analysis.

    PubMed

    Santiago, Bianca Marques; Almeida, Leopoldina; Cavalcanti, Yuri Wanderley; Magno, Marcela Baraúna; Maia, Lucianne Cople

    2017-12-22

    The age estimation is a complex procedure required in the daily practice of legal medicine. The maturity of third molars stands out by the age of 18 because these teeth are still in development. This systematic review aimed to assess the accuracy of the third molar maturity index (I 3M ), proposed by Cameriere et al. (2008), in discriminating whether an individual is under or over 18 years. Seven electronic databases were screened: PubMed, Scopus, ISI Web of Science, Cochrane Library, LILACS, SIGLE, and CAPES. Eligible studies included an assessment of I 3M accuracy at the 0.08 cut-off value. The quality assessment was performed by using QUADAS 2. Three meta-analyses (MA) were accomplished: overall, one for males and another for females. From 2397 articles identified, 16 met the eligibility criteria. Of these, two showed high risk of bias, one in the reference standard domain and the other in the flow and timing domain. The percentage of individuals correctly classified ranged from 72.4 to 96.0%. The overall MA showed pooled sensitivity of 0.86 (0.84 to 0.87; p = 0.0000) and pooled specificity of 0.93 (0.92 to 0.94; p = 0.0000). The AUC (area under the summary receiver operator characteristics curve) and DOR (diagnostic odds ratio) values were, respectively, 0.9652 and 104.68, indicating an overall high discrimination effect. Separately, better results of accuracy were found for males. High heterogeneity was achieved for both sensibility (94.6%) and specificity (88.8%). We conclude that the I 3M is a suitable and useful method for estimating adulthood regarding forensic purposes, regardless of gender.

  19. The development of a quality appraisal tool for studies of diagnostic reliability (QAREL).

    PubMed

    Lucas, Nicholas P; Macaskill, Petra; Irwig, Les; Bogduk, Nikolai

    2010-08-01

    In systematic reviews of the reliability of diagnostic tests, no quality assessment tool has been used consistently. The aim of this study was to develop a specific quality appraisal tool for studies of diagnostic reliability. Key principles for the quality of studies of diagnostic reliability were identified with reference to epidemiologic principles, existing quality appraisal checklists, and the Standards for Reporting of Diagnostic Accuracy (STARD) and Quality Assessment of Diagnostic Accuracy Studies (QUADAS) resources. Specific items that encompassed each of the principles were developed. Experts in diagnostic research provided feedback on the items that were to form the appraisal tool. This process was iterative and continued until consensus among experts was reached. The Quality Appraisal of Reliability Studies (QAREL) checklist includes 11 items that explore seven principles. Items cover the spectrum of subjects, spectrum of examiners, examiner blinding, order effects of examination, suitability of the time interval among repeated measurements, appropriate test application and interpretation, and appropriate statistical analysis. QAREL has been developed as a specific quality appraisal tool for studies of diagnostic reliability. The reliability of this tool in different contexts needs to be evaluated. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  20. The diagnostic accuracy of magnetic resonance venography in the detection of deep venous thrombosis: a systematic review and meta-analysis.

    PubMed

    Abdalla, G; Fawzi Matuk, R; Venugopal, V; Verde, F; Magnuson, T H; Schweitzer, M A; Steele, K E

    2015-08-01

    To search the literature for further evidence for the use of magnetic resonance venography (MRV) in the detection of suspected DVT and to re-evaluate the accuracy of MRV in the detection of suspected deep vein thrombosis (DVT). PubMed, EMBASE, Scopus, Cochrane, and Web of Science were searched. Study quality and the risk of bias were evaluated using the QUADAS 2. A random effects meta-analysis including subgroup and sensitivity analyses were performed. The search resulted in 23 observational studies all from academic centres. Sixteen articles were included in the meta-analysis. The summary estimates for MRV as a diagnostic non-invasive tool revealed a sensitivity of 93% (95% confidence interval [CI]: 89% to 95%) and specificity of 96% (95% CI: 94% to 97%). The heterogeneity of the studies was high. Inconsistency (I2) for sensitivity and specificity was 80.7% and 77.9%, respectively. Further studies investigating the use of MRV in the detection of suspected DVT did not offer further evidence to support the replacement of ultrasound with MRV as the first-line investigation. However, MRV may offer an alternative tool in the detection/diagnosis of DVT for whom ultrasound is inadequate or not feasible (such as in the obese patient). Copyright © 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  1. Spontaneous Subarachnoid Hemorrhage: A Systematic Review and Meta-analysis Describing the Diagnostic Accuracy of History, Physical Examination, Imaging, and Lumbar Puncture With an Exploration of Test Thresholds.

    PubMed

    Carpenter, Christopher R; Hussain, Adnan M; Ward, Michael J; Zipfel, Gregory J; Fowler, Susan; Pines, Jesse M; Sivilotti, Marco L A

    2016-09-01

    Spontaneous subarachnoid hemorrhage (SAH) is a rare, but serious etiology of headache. The diagnosis of SAH is especially challenging in alert, neurologically intact patients, as missed or delayed diagnosis can be catastrophic. The objective was to perform a diagnostic accuracy systematic review and meta-analysis of history, physical examination, cerebrospinal fluid (CSF) tests, computed tomography (CT), and clinical decision rules for spontaneous SAH. A secondary objective was to delineate probability of disease thresholds for imaging and lumbar puncture (LP). PubMed, Embase, Scopus, and research meeting abstracts were searched up to June 2015 for studies of emergency department patients with acute headache clinically concerning for spontaneous SAH. QUADAS-2 was used to assess study quality and, when appropriate, meta-analysis was conducted using random effects models. Outcomes were sensitivity, specificity, and positive (LR+) and negative (LR-) likelihood ratios. To identify test and treatment thresholds, we employed the Pauker-Kassirer method with Bernstein test indication curves using the summary estimates of diagnostic accuracy. A total of 5,022 publications were identified, of which 122 underwent full-text review; 22 studies were included (average SAH prevalence = 7.5%). Diagnostic studies differed in assessment of history and physical examination findings, CT technology, analytical techniques used to identify xanthochromia, and criterion standards for SAH. Study quality by QUADAS-2 was variable; however, most had a relatively low risk of biases. A history of neck pain (LR+ = 4.1; 95% confidence interval [CI] = 2.2 to 7.6) and neck stiffness on physical examination (LR+ = 6.6; 95% CI = 4.0 to 11.0) were the individual findings most strongly associated with SAH. Combinations of findings may rule out SAH, yet promising clinical decision rules await external validation. Noncontrast cranial CT within 6 hours of headache onset accurately ruled in (LR+ = 230; 95

  2. Spontaneous Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis Describing the Diagnostic Accuracy of History, Physical Exam, Imaging, and Lumbar Puncture with an Exploration of Test Thresholds

    PubMed Central

    Carpenter, Christopher R.; Hussain, Adnan M.; Ward, Michael J.; Zipfel, Gregory J.; Fowler, Susan; Pines, Jesse M.; Sivilotti, Marco L.A.

    2016-01-01

    Background Spontaneous subarachnoid hemorrhage (SAH) is a rare, but serious etiology of headache. The diagnosis of SAH is especially challenging in alert, neurologically intact patients, as missed or delayed diagnosis can be catastrophic. Objectives To perform a diagnostic accuracy systematic review and meta-analysis of history, physical examination, cerebrospinal fluid (CSF) tests, computed tomography (CT), and clinical decision rules for spontaneous SAH. A secondary objective was to delineate probability of disease thresholds for imaging and lumbar puncture (LP). Methods PUBMED, EMBASE, SCOPUS, and research meeting abstracts were searched up to June 2015 for studies of emergency department (ED) patients with acute headache clinically concerning for spontaneous SAH. QUADAS-2 was used to assess study quality and, when appropriate, meta-analysis was conducted using random effects models. Outcomes were sensitivity, specificity, positive (LR+) and negative (LR−) likelihood ratios. To identify test- and treatment-thresholds, we employed the Pauker-Kassirer method with Bernstein test-indication curves using the summary estimates of diagnostic accuracy. Results A total of 5,022 publications were identified, of which 122 underwent full text-review; 22 studies were included (average SAH prevalence 7.5%). Diagnostic studies differed in assessment of history and physical exam findings, CT technology, analytical techniques used to identify xanthochromia, and criterion standards for SAH. Study quality by QUADAS-2 was variable; however, most had a relatively low-risk of biases. A history of neck pain (LR+ 4.1 [95% CI 2.2-7.6]) and neck stiffness on physical exam (LR+ 6.6 [4.0-11.0]) were the individual findings most strongly associated with SAH. Combinations of findings may rule out SAH, yet promising clinical decision rules await external validation. Non-contrast cranial CT within 6 hours of headache onset accurately ruled-in (LR+ 230 [6-8700]) and ruled-out SAH (LR− 0

  3. Ultrasound for diagnosing radiographically occult scaphoid fracture.

    PubMed

    Kwee, Robert M; Kwee, Thomas C

    2018-04-04

    To systematically review the literature on the performance of ultrasound in diagnosing radiographically occult scaphoid fracture. A systematic search was performed in the MEDLINE and Embase databases. Original studies investigating the performance of ultrasound in diagnosing radiographically occult scaphoid fracture in more than 10 patients were eligible for inclusion. Studies that included both radiographically apparent and occult scaphoid fractures (at initial radiography) were only included if independent data on radiographically occult fractures were reported. Methodological quality of the studies included was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Accuracy data were extracted. Sensitivity and specificity were pooled with a bivariate random-effects model. The inclusion criteria were met by 7 studies; total sample size comprised 314 patients. All studies, except 1, included cortical disruption of the scaphoid in their diagnostic criteria. The sensitivity and specificity of ultrasound in diagnosing radiographically occult scaphoid fracture ranged from 77.8% to 100% and from 71.4% to 100% respectively, with pooled estimates of 85.6% (95% CI: 73.9%, 92.6%) and 83.3% % (95% CI: 72.0%, 90.6%) respectively. Exclusion of two studies with a high risk of bias in any QUADAS-2 domain did not affect the pooled results. Ultrasound can diagnose radiographically occult scaphoid fracture with a fairly high degree of accuracy. Because of its relatively low costs and fairly high sensitivity, ultrasound seems more cost-effective than empiric cast immobilization and may be used when CT and MRI are not readily available.

  4. Transvaginal ultrasound versus magnetic resonance imaging for preoperative assessment of myometrial infiltration in patients with endometrial cancer: a systematic review and meta-analysis

    PubMed Central

    2017-01-01

    Objective To compare the diagnostic accuracy of transvaginal ultrasound (TVS) and magnetic resonance imaging (MRI) for detecting myometrial infiltration (MI) in endometrial carcinoma. Methods An extensive search of papers comparing TVS and MRI in assessing MI in endometrial cancer was performed in MEDLINE (PubMed), Web of Science, and Cochrane Database from January 1989 to January 2017. Quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Results Our extended search identified 747 citations but after exclusions we finally included in the meta-analysis 8 articles. The risk of bias for most studies was low for most 4 domains assessed in QUADAS-2. Overall, pooled estimated sensitivity and specificity for diagnosing deep MI were 75% (95% confidence interval [CI]=67%–82%) and 82% (95% CI=75%–93%) for TVS, and 83% (95% CI=76%–89%) and 82% (95% CI=72%–89%) for MRI, respectively. No statistical differences were found when comparing both methods (p=0.314). Heterogeneity was low for sensitivity and high for specificity for TVS and MRI. Conclusion MRI showed a better sensitivity than TVS for detecting deep MI in women with endometrial cancer. However, the difference observed was not statistically significant. PMID:29027404

  5. Transvaginal ultrasound versus magnetic resonance imaging for preoperative assessment of myometrial infiltration in patients with endometrial cancer: a systematic review and meta-analysis.

    PubMed

    Alcázar, Juan Luis; Gastón, Begoña; Navarro, Beatriz; Salas, Rocío; Aranda, Juana; Guerriero, Stefano

    2017-11-01

    To compare the diagnostic accuracy of transvaginal ultrasound (TVS) and magnetic resonance imaging (MRI) for detecting myometrial infiltration (MI) in endometrial carcinoma. An extensive search of papers comparing TVS and MRI in assessing MI in endometrial cancer was performed in MEDLINE (PubMed), Web of Science, and Cochrane Database from January 1989 to January 2017. Quality was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. Our extended search identified 747 citations but after exclusions we finally included in the meta-analysis 8 articles. The risk of bias for most studies was low for most 4 domains assessed in QUADAS-2. Overall, pooled estimated sensitivity and specificity for diagnosing deep MI were 75% (95% confidence interval [CI]=67%-82%) and 82% (95% CI=75%-93%) for TVS, and 83% (95% CI=76%-89%) and 82% (95% CI=72%-89%) for MRI, respectively. No statistical differences were found when comparing both methods (p=0.314). Heterogeneity was low for sensitivity and high for specificity for TVS and MRI. MRI showed a better sensitivity than TVS for detecting deep MI in women with endometrial cancer. However, the difference observed was not statistically significant. Copyright © 2017. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology

  6. The diagnostic accuracy of screening questionnaires for the identification of adults with epilepsy: a systematic review.

    PubMed

    Keezer, Mark R; Bouma, Hanni K; Wolfson, Christina

    2014-11-01

    To describe the diagnostic accuracy of screening questionnaires to identify epilepsy in adults, we performed a systematic review of diagnostic studies that assessed the sensitivity and specificity of such screening questionnaires as compared to a physician's clinical assessment. We searched Ovid MEDLINE (1946 to present) and Ovid EMBASE (1947 to present) for studies that estimated the sensitivity and specificity of nonphysician administered screening questionnaires for adults with epilepsy. Both telephone and in-person administered questionnaires were included, whether applied to population or hospital/clinic-based cohorts. The risk of bias was assessed using the Quality Assessment of Diagnostic Studies-2 (QUADAS-2) tool. Our initial search strategy resulted in 917 records. We found nine studies eligible for inclusion. The estimated sensitivity and specificity of the questionnaires used to identify persons with a lifetime history of epilepsy ranged from 81.5% to 100% and 65.6% to 99.2%, respectively. The sensitivity and specificity of these questionnaires in identifying persons with active epilepsy ranged from 48.6% to 100% and 73.9% to 99.9%, respectively. Overall we found a high risk of bias in patient selection and study flow in the majority of studies. We identified nine validation studies of epilepsy screening questionnaires, summarized their study characteristics, presented their results, and performed a rigorous quality assessment. This review serves as a basis for future studies by providing a systematic review of existing work. Future research addressing previous limitations will ultimately allow us to more accurately estimate the burden and risk of epilepsy in the general population. Wiley Periodicals, Inc. © 2014 International League Against Epilepsy.

  7. Air traffic control surveillance accuracy and update rate study

    NASA Technical Reports Server (NTRS)

    Craigie, J. H.; Morrison, D. D.; Zipper, I.

    1973-01-01

    The results of an air traffic control surveillance accuracy and update rate study are presented. The objective of the study was to establish quantitative relationships between the surveillance accuracies, update rates, and the communication load associated with the tactical control of aircraft for conflict resolution. The relationships are established for typical types of aircraft, phases of flight, and types of airspace. Specific cases are analyzed to determine the surveillance accuracies and update rates required to prevent two aircraft from approaching each other too closely.

  8. Accuracy of Percutaneous Core Biopsy in the Diagnosis of Small Renal Masses (≤ 4.0 cm): A Meta-analysis.

    PubMed

    He, Qiqi; Wang, Hanzhang; Kenyon, Jonathan; Liu, Guiming; Yang, Li; Tian, Junqiang; Yue, Zhongjin; Wang, Zhiping

    2015-01-01

    To use meta-analysis to determine the accuracy of percutaneous core needle biopsy in the diagnosis of small renal masses (SMRs ≤ 4.0 cm). Studies were identified by searching PubMed, Embase, and the Cochrane Library database up to March 2013. Two of the authors independently assessed the study quality using QUADAS-2 tool and extracted data that met the inclusion criteria. The sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR) and also summary receiver operating characteristic (SROC) curve were investigated and draw. Deek's funnel plot was used to evaluate the publication bias. A total of 9 studies with 788 patients (803 biopsies) were included. Failed biopsies without repeated or aborted from follow-up/surgery result were excluded (232 patients and 353 biopsies). For all cases, the pooled sensitivity was 94.0% (95% CI: 91.0%, 95.0%), the pooled positive likelihood was 22.57 (95 % CI: 9.20-55.34), the pooled negative likelihood was 0.09 (95 % CI: 0.06-0.13), the pooled DOR was 296.52(95 % CI: 99. 42-884.38). The area under the curve of SROC analysis was 0.959 ± 0.0254. Imaging-guided percutaneous core needle biopsy of small renal masses (SMRs ≤ 4.0 cm) is highly accurate to malignant tumor diagnosis with unknown metastatic status and could be offered to some patients after clinic judgment prior to surgical intervention consideration.

  9. Biomarkers of acute appendicitis: systematic review and cost-benefit trade-off analysis.

    PubMed

    Acharya, Amish; Markar, Sheraz R; Ni, Melody; Hanna, George B

    2017-03-01

    Acute appendicitis is the most common surgical emergency and can represent a challenging diagnosis, with a negative appendectomy rate as high as 20 %. This review aimed to evaluate the clinical utility of individual biomarkers in the diagnosis of appendicitis and appraise the quality of these studies. A systematic review of the literature between January 2000 and September 2015 using of PubMed, OvidMedline, EMBASE and Google Scholar was conducted. Studies in which the diagnostic accuracy, statistical heterogeneity and predictive ability for severity of several biomarkers could be elicited were included. Information regarding costs and process times was retrieved from the regional laboratory. European surgeons blinded to these reviews were independently asked to rank which characteristics of biomarkers were most important in acute appendicitis to inform a cost-benefit trade-off. Sensitivity testing and the QUADAS-2 tool were used to assess the robustness of the analysis and study quality, respectively. Sixty-two studies met the inclusion criteria and were assessed. Traditional biomarkers (such as white cell count) were found to have a moderate diagnostic accuracy (0.75) but lower costs in the diagnosis of acute appendicitis. Conversely, novel markers (pro-calcitonin, IL 6 and urinary 5-HIAA) were found to have high process-related costs including analytical times, but improved diagnostic accuracy. QUADAS-2 analysis revealed significant potential biases in the literature. When assessing biomarkers, an appreciation of the trade-offs between the costs and benefits of individual biomarkers is needed. Further studies should seek to investigate new biomarkers and address concerns over bias, in order to improve the diagnosis of acute appendicitis.

  10. Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: A systematic review and meta-analysis.

    PubMed

    Taggar, Jaspal S; Coleman, Tim; Lewis, Sarah; Heneghan, Carl; Jones, Matthew

    2016-08-01

    Pulse palpation has been recommended as the first step of screening to detect atrial fibrillation. We aimed to determine and compare the accuracy of different methods for detecting pulse irregularities caused by atrial fibrillation. We systematically searched MEDLINE, EMBASE, CINAHL and LILACS until 16 March 2015. Two reviewers identified eligible studies, extracted data and appraised quality using the QUADAS-2 instrument. Meta-analysis, using the bivariate hierarchical random effects method, determined average operating points for sensitivities, specificities, positive and negative likelihood ratios (PLR, NLR); we constructed summary receiver operating characteristic plots. Twenty-one studies investigated 39 interventions (n = 15,129 pulse assessments) for detecting atrial fibrillation. Compared to 12-lead electrocardiography (ECG) diagnosed atrial fibrillation, blood pressure monitors (BPMs; seven interventions) and non-12-lead ECGs (20 interventions) had the greatest accuracy for detecting pulse irregularities attributable to atrial fibrillation (BPM: sensitivity 0.98 (95% confidence interval (CI) 0.92-1.00), specificity 0.92 (95% CI 0.88-0.95), PLR 12.1 (95% CI 8.2-17.8) and NLR 0.02 (95% CI 0.00-0.09); non-12-lead ECG: sensitivity 0.91 (95% CI 0.86-0.94), specificity 0.95 (95% CI 0.92-0.97), PLR 20.1 (95% CI 12-33.7), NLR 0.09 (95% CI 0.06-0.14)). There were similar findings for smartphone applications (six interventions) although these studies were small in size. The sensitivity and specificity of pulse palpation (six interventions) were 0.92 (95% CI 0.85-0.96) and 0.82 (95% CI 0.76-0.88), respectively (PLR 5.2 (95% CI 3.8-7.2), NLR 0.1 (95% CI 0.05-0.18)). BPMs and non-12-lead ECG were most accurate for detecting pulse irregularities caused by atrial fibrillation; other technologies may therefore be pragmatic alternatives to pulse palpation for the first step of atrial fibrillation screening. © The European Society of Cardiology 2015.

  11. Accuracy of methods for detecting an irregular pulse and suspected atrial fibrillation: A systematic review and meta-analysis

    PubMed Central

    Coleman, Tim; Lewis, Sarah; Heneghan, Carl; Jones, Matthew

    2015-01-01

    Background Pulse palpation has been recommended as the first step of screening to detect atrial fibrillation. We aimed to determine and compare the accuracy of different methods for detecting pulse irregularities caused by atrial fibrillation. Methods We systematically searched MEDLINE, EMBASE, CINAHL and LILACS until 16 March 2015. Two reviewers identified eligible studies, extracted data and appraised quality using the QUADAS-2 instrument. Meta-analysis, using the bivariate hierarchical random effects method, determined average operating points for sensitivities, specificities, positive and negative likelihood ratios (PLR, NLR); we constructed summary receiver operating characteristic plots. Results Twenty-one studies investigated 39 interventions (n = 15,129 pulse assessments) for detecting atrial fibrillation. Compared to 12-lead electrocardiography (ECG) diagnosed atrial fibrillation, blood pressure monitors (BPMs; seven interventions) and non-12-lead ECGs (20 interventions) had the greatest accuracy for detecting pulse irregularities attributable to atrial fibrillation (BPM: sensitivity 0.98 (95% confidence interval (CI) 0.92–1.00), specificity 0.92 (95% CI 0.88–0.95), PLR 12.1 (95% CI 8.2–17.8) and NLR 0.02 (95% CI 0.00–0.09); non-12-lead ECG: sensitivity 0.91 (95% CI 0.86–0.94), specificity 0.95 (95% CI 0.92–0.97), PLR 20.1 (95% CI 12–33.7), NLR 0.09 (95% CI 0.06–0.14)). There were similar findings for smartphone applications (six interventions) although these studies were small in size. The sensitivity and specificity of pulse palpation (six interventions) were 0.92 (95% CI 0.85–0.96) and 0.82 (95% CI 0.76–0.88), respectively (PLR 5.2 (95% CI 3.8–7.2), NLR 0.1 (95% CI 0.05–0.18)). Conclusions BPMs and non-12-lead ECG were most accurate for detecting pulse irregularities caused by atrial fibrillation; other technologies may therefore be pragmatic alternatives to pulse palpation for the first step of atrial fibrillation screening

  12. STARD 2015 guidelines for reporting diagnostic accuracy studies: explanation and elaboration

    PubMed Central

    Cohen, Jérémie F; Korevaar, Daniël A; Altman, Douglas G; Bruns, David E; Gatsonis, Constantine A; Hooft, Lotty; Irwig, Les; Levine, Deborah; Reitsma, Johannes B; de Vet, Henrica C W; Bossuyt, Patrick M M

    2016-01-01

    Diagnostic accuracy studies are, like other clinical studies, at risk of bias due to shortcomings in design and conduct, and the results of a diagnostic accuracy study may not apply to other patient groups and settings. Readers of study reports need to be informed about study design and conduct, in sufficient detail to judge the trustworthiness and applicability of the study findings. The STARD statement (Standards for Reporting of Diagnostic Accuracy Studies) was developed to improve the completeness and transparency of reports of diagnostic accuracy studies. STARD contains a list of essential items that can be used as a checklist, by authors, reviewers and other readers, to ensure that a report of a diagnostic accuracy study contains the necessary information. STARD was recently updated. All updated STARD materials, including the checklist, are available at http://www.equator-network.org/reporting-guidelines/stard. Here, we present the STARD 2015 explanation and elaboration document. Through commented examples of appropriate reporting, we clarify the rationale for each of the 30 items on the STARD 2015 checklist, and describe what is expected from authors in developing sufficiently informative study reports. PMID:28137831

  13. Commercial enzyme-linked immunosorbent assay versuspolymerase chain reaction for the diagnosis of chronic Chagas disease: a systematic review and meta-analysis.

    PubMed

    Brasil, Pedro Emmanuel Alvarenga Americano do; Castro, Rodolfo; Castro, Liane de

    2016-01-01

    Chronic Chagas disease diagnosis relies on laboratory tests due to its clinical characteristics. The aim of this research was to review commercial enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) diagnostic test performance. Performance of commercial ELISA or PCR for the diagnosis of chronic Chagas disease were systematically searched in PubMed, Scopus, Embase, ISI Web, and LILACS through the bibliography from 1980-2014 and by contact with the manufacturers. The risk of bias was assessed with QUADAS-2. Heterogeneity was estimated with the I2 statistic. Accuracies provided by the manufacturers usually overestimate the accuracy provided by academia. The risk of bias is high in most tests and in most QUADAS dimensions. Heterogeneity is high in either sensitivity, specificity, or both. The evidence regarding commercial ELISA and ELISA-rec sensitivity and specificity indicates that there is overestimation. The current recommendation to use two simultaneous serological tests can be supported by the risk of bias analysis and the amount of heterogeneity but not by the observed accuracies. The usefulness of PCR tests are debatable and health care providers should not order them on a routine basis. PCR may be used in selected cases due to its potential to detect seronegative subjects.

  14. Commercial enzyme-linked immunosorbent assay versus polymerase chain reaction for the diagnosis of chronic Chagas disease: a systematic review and meta-analysis

    PubMed Central

    do Brasil, Pedro Emmanuel Alvarenga Americano; Castro, Rodolfo; de Castro, Liane

    2016-01-01

    Chronic Chagas disease diagnosis relies on laboratory tests due to its clinical characteristics. The aim of this research was to review commercial enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR) diagnostic test performance. Performance of commercial ELISA or PCR for the diagnosis of chronic Chagas disease were systematically searched in PubMed, Scopus, Embase, ISI Web, and LILACS through the bibliography from 1980-2014 and by contact with the manufacturers. The risk of bias was assessed with QUADAS-2. Heterogeneity was estimated with the I2 statistic. Accuracies provided by the manufacturers usually overestimate the accuracy provided by academia. The risk of bias is high in most tests and in most QUADAS dimensions. Heterogeneity is high in either sensitivity, specificity, or both. The evidence regarding commercial ELISA and ELISA-rec sensitivity and specificity indicates that there is overestimation. The current recommendation to use two simultaneous serological tests can be supported by the risk of bias analysis and the amount of heterogeneity but not by the observed accuracies. The usefulness of PCR tests are debatable and health care providers should not order them on a routine basis. PCR may be used in selected cases due to its potential to detect seronegative subjects. PMID:26814640

  15. Accuracy and Resolution in Micro-earthquake Tomographic Inversion Studies

    NASA Astrophysics Data System (ADS)

    Hutchings, L. J.; Ryan, J.

    2010-12-01

    Accuracy and resolution are complimentary properties necessary to interpret the results of earthquake location and tomography studies. Accuracy is the how close an answer is to the “real world”, and resolution is who small of node spacing or earthquake error ellipse one can achieve. We have modified SimulPS (Thurber, 1986) in several ways to provide a tool for evaluating accuracy and resolution of potential micro-earthquake networks. First, we provide synthetic travel times from synthetic three-dimensional geologic models and earthquake locations. We use this to calculate errors in earthquake location and velocity inversion results when we perturb these models and try to invert to obtain these models. We create as many stations as desired and can create a synthetic velocity model with any desired node spacing. We apply this study to SimulPS and TomoDD inversion studies. “Real” travel times are perturbed with noise and hypocenters are perturbed to replicate a starting location away from the “true” location, and inversion is performed by each program. We establish travel times with the pseudo-bending ray tracer and use the same ray tracer in the inversion codes. This, of course, limits our ability to test the accuracy of the ray tracer. We developed relationships for the accuracy and resolution expected as a function of the number of earthquakes and recording stations for typical tomographic inversion studies. Velocity grid spacing started at 1km, then was decreased to 500m, 100m, 50m and finally 10m to see if resolution with decent accuracy at that scale was possible. We considered accuracy to be good when we could invert a velocity model perturbed by 50% back to within 5% of the original model, and resolution to be the size of the grid spacing. We found that 100 m resolution could obtained by using 120 stations with 500 events, bu this is our current limit. The limiting factors are the size of computers needed for the large arrays in the inversion and a

  16. The De Winter ECG pattern: morphology and accuracy for diagnosing acute coronary occlusion: systematic review.

    PubMed

    Morris, Niall P; Body, Richard

    2017-08-01

    The De Winter ECG pattern has been reported to indicate acute left anterior descending coronary artery occlusion and is often considered to be an 'ST elevation myocardial infarction (STEMI) equivalent'. We aimed to investigate the morphology of the 'De Winter ECG pattern' and evaluate the test characteristics of the De Winter pattern for the diagnosis of acute coronary occlusion. We identified papers through the Medline, EMBASE and COCHRANE databases and screened for bias using QUADAS-2. First, measurements were recorded from every ECG reported in the literature and aggregated. Second, diagnostic accuracy data from eligible cohort studies were extracted. The primary outcome was defined as at least 70% angiographic stenosis of a major epicardial vessel. Thirteen papers reported data relevant to question 1 and three papers reported data relevant to question 2. All ECGs showed maximal up-sloping ST depression in lead V3 with a median amplitude of 0.3 mV (interquartile range: 0.2-4 mV). T-wave height peaked in lead V3 with a median amplitude 0.9 mV (interquartile range: 0.8-1.1 mV). The De Winter pattern had positive predictive values of 95.2% (95% confidence interval: 76.2-99.9%), 100% (69.2-100.0%) and 100% (51.7-100%) in the three respective diagnostic studies. There is limited evidence that the De Winter ECG pattern is a 'STEMI equivalent'. The available data suggest that the pattern has high positive predictive value for acute occlusion. Further research is required to evaluate specificity and to determine whether rapid revascularization improves mortality.

  17. Overinterpretation and misreporting of diagnostic accuracy studies: evidence of "spin".

    PubMed

    Ochodo, Eleanor A; de Haan, Margriet C; Reitsma, Johannes B; Hooft, Lotty; Bossuyt, Patrick M; Leeflang, Mariska M G

    2013-05-01

    To estimate the frequency of distorted presentation and overinterpretation of results in diagnostic accuracy studies. MEDLINE was searched for diagnostic accuracy studies published between January and June 2010 in journals with an impact factor of 4 or higher. Articles included were primary studies of the accuracy of one or more tests in which the results were compared with a clinical reference standard. Two authors scored each article independently by using a pretested data-extraction form to identify actual overinterpretation and practices that facilitate overinterpretation, such as incomplete reporting of study methods or the use of inappropriate methods (potential overinterpretation). The frequency of overinterpretation was estimated in all studies and in a subgroup of imaging studies. Of the 126 articles, 39 (31%; 95% confidence interval [CI]: 23, 39) contained a form of actual overinterpretation, including 29 (23%; 95% CI: 16, 30) with an overly optimistic abstract, 10 (8%; 96% CI: 3%, 13%) with a discrepancy between the study aim and conclusion, and eight with conclusions based on selected subgroups. In our analysis of potential overinterpretation, authors of 89% (95% CI: 83%, 94%) of the studies did not include a sample size calculation, 88% (95% CI: 82%, 94%) did not state a test hypothesis, and 57% (95% CI: 48%, 66%) did not report CIs of accuracy measurements. In 43% (95% CI: 34%, 52%) of studies, authors were unclear about the intended role of the test, and in 3% (95% CI: 0%, 6%) they used inappropriate statistical tests. A subgroup analysis of imaging studies showed 16 (30%; 95% CI: 17%, 43%) and 53 (100%; 95% CI: 92%, 100%) contained forms of actual and potential overinterpretation, respectively. Overinterpretation and misreporting of results in diagnostic accuracy studies is frequent in journals with high impact factors. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120527/-/DC1. © RSNA, 2013.

  18. STARD 2015: An Updated List of Essential Items for Reporting Diagnostic Accuracy Studies.

    PubMed

    Bossuyt, Patrick M; Reitsma, Johannes B; Bruns, David E; Gatsonis, Constantine A; Glasziou, Paul P; Irwig, Les; Lijmer, Jeroen G; Moher, David; Rennie, Drummond; de Vet, Henrica C W; Kressel, Herbert Y; Rifai, Nader; Golub, Robert M; Altman, Douglas G; Hooft, Lotty; Korevaar, Daniël A; Cohen, Jérémie F

    2015-12-01

    Incomplete reporting has been identified as a major source of avoidable waste in biomedical research. Essential information is often not provided in study reports, impeding the identification, critical appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement was developed. Here we present STARD 2015, an updated list of 30 essential items that should be included in every report of a diagnostic accuracy study. This update incorporates recent evidence about sources of bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such, STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy studies.

  19. STARD 2015: An Updated List of Essential Items for Reporting Diagnostic Accuracy Studies.

    PubMed

    Bossuyt, Patrick M; Reitsma, Johannes B; Bruns, David E; Gatsonis, Constantine A; Glasziou, Paul P; Irwig, Les; Lijmer, Jeroen G; Moher, David; Rennie, Drummond; de Vet, Henrica C W; Kressel, Herbert Y; Rifai, Nader; Golub, Robert M; Altman, Douglas G; Hooft, Lotty; Korevaar, Daniël A; Cohen, Jérémie F

    2015-12-01

    Incomplete reporting has been identified as a major source of avoidable waste in biomedical research. Essential information is often not provided in study reports, impeding the identification, critical appraisal, and replication of studies. To improve the quality of reporting of diagnostic accuracy studies, the Standards for Reporting of Diagnostic Accuracy Studies (STARD) statement was developed. Here we present STARD 2015, an updated list of 30 essential items that should be included in every report of a diagnostic accuracy study. This update incorporates recent evidence about sources of bias and variability in diagnostic accuracy and is intended to facilitate the use of STARD. As such, STARD 2015 may help to improve completeness and transparency in reporting of diagnostic accuracy studies. © 2015 American Association for Clinical Chemistry.

  20. Indexing of Diagnostic Accuracy Studies in MEDLINE and EMBASE

    PubMed Central

    Wilczynski, Nancy L.; Haynes, R. Brian

    2007-01-01

    Background: STAndards for Reporting of Diagnostic Accuracy (STARD) were published in 2003 and endorsed by some journals but not others. Objective: To determine whether the quality of indexing of diagnostic accuracy studies in MEDLINE and EMBASE has improved since the STARD statement was published. Design: Evaluate the change in the mean number of “accurate index terms” assigned to diagnostic accuracy studies, comparing STARD (endorsing) and non-STARD (non-endorsing) journals, for 2 years before and after STARD publication. Results: In MEDLINE, no differences in indexing quality were found for STARD and non-STARD journals before or after the STARD statement was published in 2003. In EMBASE, indexing in STARD journals improved compared with non-STARD journals (p = 0.02). However, articles in STARD journals had half the number of accurate indexing terms as articles in non-STARD journals, both before and after STARD statement publication (p < 0.001). PMID:18693947

  1. Indexing of diagnosis accuracy studies in MEDLINE and EMBASE.

    PubMed

    Wilczynski, Nancy L; Haynes, R Brian

    2007-10-11

    STAndards for Reporting of Diagnostic Accuracy (STARD) were published in 2003 and endorsed by some journals but not others. To determine whether the quality of indexing of diagnostic accuracy studies in MEDLINE and EMBASE has improved since the STARD statement was published. Evaluate the change in the mean number of "accurate index terms" assigned to diagnostic accuracy studies, comparing STARD (endorsing) and non-STARD (non-endorsing) journals, for 2 years before and after STARD publication. In MEDLINE, no differences in indexing quality were found for STARD and non-STARD journals before or after the STARD statement was published in 2003. In EMBASE, indexing in STARD journals improved compared with non-STARD journals (p = 0.02). However, articles in STARD journals had half the number of accurate indexing terms as articles in non-STARD journals, both before and after STARD statement publication (p < 0.001).

  2. High-accuracy mass spectrometry for fundamental studies.

    PubMed

    Kluge, H-Jürgen

    2010-01-01

    Mass spectrometry for fundamental studies in metrology and atomic, nuclear and particle physics requires extreme sensitivity and efficiency as well as ultimate resolving power and accuracy. An overview will be given on the global status of high-accuracy mass spectrometry for fundamental physics and metrology. Three quite different examples of modern mass spectrometric experiments in physics are presented: (i) the retardation spectrometer KATRIN at the Forschungszentrum Karlsruhe, employing electrostatic filtering in combination with magnetic-adiabatic collimation-the biggest mass spectrometer for determining the smallest mass, i.e. the mass of the electron anti-neutrino, (ii) the Experimental Cooler-Storage Ring at GSI-a mass spectrometer of medium size, relative to other accelerators, for determining medium-heavy masses and (iii) the Penning trap facility, SHIPTRAP, at GSI-the smallest mass spectrometer for determining the heaviest masses, those of super-heavy elements. Finally, a short view into the future will address the GSI project HITRAP at GSI for fundamental studies with highly-charged ions.

  3. Experimental studies of high-accuracy RFID localization with channel impairments

    NASA Astrophysics Data System (ADS)

    Pauls, Eric; Zhang, Yimin D.

    2015-05-01

    Radio frequency identification (RFID) systems present an incredibly cost-effective and easy-to-implement solution to close-range localization. One of the important applications of a passive RFID system is to determine the reader position through multilateration based on the estimated distances between the reader and multiple distributed reference tags obtained from, e.g., the received signal strength indicator (RSSI) readings. In practice, the achievable accuracy of passive RFID reader localization suffers from many factors, such as the distorted RSSI reading due to channel impairments in terms of the susceptibility to reader antenna patterns and multipath propagation. Previous studies have shown that the accuracy of passive RFID localization can be significantly improved by properly modeling and compensating for such channel impairments. The objective of this paper is to report experimental study results that validate the effectiveness of such approaches for high-accuracy RFID localization. We also examine a number of practical issues arising in the underlying problem that limit the accuracy of reader-tag distance measurements and, therefore, the estimated reader localization. These issues include the variations in tag radiation characteristics for similar tags, effects of tag orientations, and reader RSS quantization and measurement errors. As such, this paper reveals valuable insights of the issues and solutions toward achieving high-accuracy passive RFID localization.

  4. The diagnostic accuracy of the Ascertain Dementia 8 questionnaire for detecting cognitive impairment in primary care in the community, clinics and hospitals: a systematic review and meta-analysis

    PubMed Central

    Chen, Hsin-Hao; Sun, Fang-Ju; Yeh, Tzu-Lin; Liu, Hsueh-Erh; Huang, Hsiu-Li; Kuo, Benjamin Ing-Tiau; Huang, Hsin-Yi

    2018-01-01

    Abstract Background The prevalence of cognitive impairment is increasing due to the aging population, and early detection is essential clinically. The Ascertain Dementia 8 (AD8) questionnaire is a brief informant-based measure recently developed to assess early cognitive impairment, however, its overall diagnostic performance is controversial. The objective of this meta-analysis was to assess the diagnostic accuracy of the AD8 for cognitive impairment. Methods All relevant studies were collected from databases including MEDLINE, EMBASE and the Cochrane Library up to April 2017. We used QUADAS-2 to assess the methodological quality after the systematic search. The accuracy data and potential confounding variables were extracted from the eligible studies which included those in English and non-English. All analyses were performed using the Midas module in Stata 14.0 and Meta-DiSc 1.4 software. Results Seven relevant studies including 3728 subjects were collected, and classified into two subgroups according to the severity of cognitive impairment. The overall sensitivity (0.72, 0.91) was superior to specificity (0.67, 0.78). The pooled negative likelihood ratio (0.17, 0.13) was better than the positive likelihood ratio (2.52, 3.94). The areas under the summary receiver operating characteristic curve were 0.83 and 0.92, respectively. Meta-regression analysis showed that location (community versus non-community) may be the source of heterogeneity. The average administration time was less than 3 minutes. Conclusion Our findings suggest that the AD8 is a competitive tool for clinically screening cognitive impairment and has an optimal administration time in the busy primary care setting. Subjects with an AD8 score ≧2 should be highly suspected to have cognitive impairment and a further definite diagnosis is needed. PMID:29045636

  5. Effects of accuracy motivation and anchoring on metacomprehension judgment and accuracy.

    PubMed

    Zhao, Qin

    2012-01-01

    The current research investigates how accuracy motivation impacts anchoring and adjustment in metacomprehension judgment and how accuracy motivation and anchoring affect metacomprehension accuracy. Participants were randomly assigned to one of six conditions produced by the between-subjects factorial design involving accuracy motivation (incentive or no) and peer performance anchor (95%, 55%, or no). Two studies showed that accuracy motivation did not impact anchoring bias, but the adjustment-from-anchor process occurred. Accuracy incentive increased anchor-judgment gap for the 95% anchor but not for the 55% anchor, which induced less certainty about the direction of adjustment. The findings offer support to the integrative theory of anchoring. Additionally, the two studies revealed a "power struggle" between accuracy motivation and anchoring in influencing metacomprehension accuracy. Accuracy motivation could improve metacomprehension accuracy in spite of anchoring effect, but if anchoring effect is too strong, it could overpower the motivation effect. The implications of the findings were discussed.

  6. Meta-epidemiologic study showed frequent time trends in summary estimates from meta-analyses of diagnostic accuracy studies.

    PubMed

    Cohen, Jérémie F; Korevaar, Daniël A; Wang, Junfeng; Leeflang, Mariska M; Bossuyt, Patrick M

    2016-09-01

    To evaluate changes over time in summary estimates from meta-analyses of diagnostic accuracy studies. We included 48 meta-analyses from 35 MEDLINE-indexed systematic reviews published between September 2011 and January 2012 (743 diagnostic accuracy studies; 344,015 participants). Within each meta-analysis, we ranked studies by publication date. We applied random-effects cumulative meta-analysis to follow how summary estimates of sensitivity and specificity evolved over time. Time trends were assessed by fitting a weighted linear regression model of the summary accuracy estimate against rank of publication. The median of the 48 slopes was -0.02 (-0.08 to 0.03) for sensitivity and -0.01 (-0.03 to 0.03) for specificity. Twelve of 96 (12.5%) time trends in sensitivity or specificity were statistically significant. We found a significant time trend in at least one accuracy measure for 11 of the 48 (23%) meta-analyses. Time trends in summary estimates are relatively frequent in meta-analyses of diagnostic accuracy studies. Results from early meta-analyses of diagnostic accuracy studies should be considered with caution. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Sample size in studies on diagnostic accuracy in ophthalmology: a literature survey.

    PubMed

    Bochmann, Frank; Johnson, Zoe; Azuara-Blanco, Augusto

    2007-07-01

    To assess the sample sizes used in studies on diagnostic accuracy in ophthalmology. Design and sources: A survey literature published in 2005. The frequency of reporting calculations of sample sizes and the samples' sizes were extracted from the published literature. A manual search of five leading clinical journals in ophthalmology with the highest impact (Investigative Ophthalmology and Visual Science, Ophthalmology, Archives of Ophthalmology, American Journal of Ophthalmology and British Journal of Ophthalmology) was conducted by two independent investigators. A total of 1698 articles were identified, of which 40 studies were on diagnostic accuracy. One study reported that sample size was calculated before initiating the study. Another study reported consideration of sample size without calculation. The mean (SD) sample size of all diagnostic studies was 172.6 (218.9). The median prevalence of the target condition was 50.5%. Only a few studies consider sample size in their methods. Inadequate sample sizes in diagnostic accuracy studies may result in misleading estimates of test accuracy. An improvement over the current standards on the design and reporting of diagnostic studies is warranted.

  8. Efficient strategies to find diagnostic test accuracy studies in kidney journals.

    PubMed

    Rogerson, Thomas E; Ladhani, Maleeka; Mitchell, Ruth; Craig, Jonathan C; Webster, Angela C

    2015-08-01

    Nephrologists looking for quick answers to diagnostic clinical questions in MEDLINE can use a range of published search strategies or Clinical Query limits to improve the precision of their searches. We aimed to evaluate existing search strategies for finding diagnostic test accuracy studies in nephrology journals. We assessed the accuracy of 14 search strategies for retrieving diagnostic test accuracy studies from three nephrology journals indexed in MEDLINE. Two investigators hand searched the same journals to create a reference set of diagnostic test accuracy studies to compare search strategy results against. We identified 103 diagnostic test accuracy studies, accounting for 2.1% of all studies published. The most specific search strategy was the Narrow Clinical Queries limit (sensitivity: 0.20, 95% CI 0.13-0.29; specificity: 0.99, 95% CI 0.99-0.99). Using the Narrow Clinical Queries limit, a searcher would need to screen three (95% CI 2-6) articles to find one diagnostic study. The most sensitive search strategy was van der Weijden 1999 Extended (sensitivity: 0.95; 95% CI 0.89-0.98; specificity 0.55, 95% CI 0.53-0.56) but required a searcher to screen 24 (95% CI 23-26) articles to find one diagnostic study. Bachmann 2002 was the best balanced search strategy, which was sensitive (0.88, 95% CI 0.81-0.94), but also specific (0.74, 95% CI 0.73-0.75), with a number needed to screen of 15 (95% CI 14-17). Diagnostic studies are infrequently published in nephrology journals. The addition of a strategy for diagnostic studies to a subject search strategy in MEDLINE may reduce the records needed to screen while preserving adequate search sensitivity for routine clinical use. © 2015 Asian Pacific Society of Nephrology.

  9. Systematic Review and Meta-Analysis of Diagnostic Accuracy of Serum Refractometry and Brix Refractometry for the Diagnosis of Inadequate Transfer of Passive Immunity in Calves.

    PubMed

    Buczinski, S; Gicquel, E; Fecteau, G; Takwoingi, Y; Chigerwe, M; Vandeweerd, J M

    2018-01-01

    Transfer of passive immunity in calves can be assessed by direct measurement of immunoglobulin G (IgG) by methods such as radial immunodiffusion (RID) or turbidimetric immunoassay (TIA). IgG can also be measured indirectly by methods such as serum refractometry (REF) or Brix refractometry (BRIX). To determine the accuracy of REF and BRIX for assessment of inadequate transfer of passive immunity (ITPI) in calves. Systematic review and meta-analysis of diagnostic accuracy studies. Databases (PubMed and CAB Abstract, Searchable Proceedings of Animal Science) and Google Scholar were searched for relevant studies. Studies were eligible if the accuracy (sensitivity and specificity) of REF or BRIX was determined using direct measurement of IgG by RID or turbidimetry as the reference standard. The study population included calves <14 days old that were fed with natural colostrum (colostrum replacement products were excluded). Quality assessment was performed by the QUADAS-2 tool. Hierarchical models were used for meta-analysis. From 1,291 references identified, 13 studies of 3,788 calves were included. Of these, 11 studies evaluated REF and 5 studies evaluated BRIX. The median (range) prevalence of ITPI (defined as calves with IgG <10 g/L by RID or TIA) was 21% (1.3-56%). Risk of bias and applicability concerns were generally low or unclear. For REF, summary estimates were obtained for 2 different cutoffs: 5.2 g/dL (6 studies) and 5.5 g/dL (5 studies). For the 5.2 g/dL cutoff, the summary sensitivity (95% CI) and specificity (95% CI) were 76.1% (63.8-85.2%) and 89.3% (82.3-93.7%), and 88.2% (80.2-93.3%) and 77.9% (74.5-81.0%) for the 5.5 g/dL cutoff. Due to the low number of studies using the same cutoffs, summary estimates could not be obtained for BRIX. Despite their widespread use on dairy farms, evidence about the optimal strategy for using refractometry, including the optimal cutoff, are sparse (especially for BRIX). When using REF to rule out ITPI in herds, the 5.5 g

  10. Prediction of miscarriage in women with viable intrauterine pregnancy-A systematic review and diagnostic accuracy meta-analysis.

    PubMed

    Pillai, Rekha N; Konje, Justin C; Richardson, Matthew; Tincello, Douglas G; Potdar, Neelam

    2018-01-01

    Both ultrasound and biochemical markers either alone or in combination have been described in the literature for the prediction of miscarriage. We performed this systematic review and meta-analysis to determine the best combination of biochemical, ultrasound and demographic markers to predict miscarriage in women with viable intrauterine pregnancy. The electronic database search included Medline (1946-June 2017), Embase (1980-June 2017), CINAHL (1981-June 2017) and Cochrane library. Key MESH and Boolean terms were used for the search. Data extraction and collection was performed based on the eligibility criteria by two authors independently. Quality assessment of the individual studies was done using QUADAS 2 (Quality Assessment for Diagnostic Accuracy Studies-2: A Revised Tool) and statistical analysis performed using the Cochrane systematic review manager 5.3 and STATA vs.13.0. Due to the diversity of the combinations used for prediction in the included papers it was not possible to perform a meta-analysis on combination markers. Therefore, we proceeded to perform a meta-analysis on ultrasound markers alone to determine the best marker that can help to improve the diagnostic accuracy of predicting miscarriage in women with viable intrauterine pregnancy. The systematic review identified 18 eligible studies for the quantitative meta-analysis with a total of 5584 women. Among the ultrasound scan markers, fetal bradycardia (n=10 studies, n=1762 women) on hierarchical summary receiver operating characteristic showed sensitivity of 68.41%, specificity of 97.84%, positive likelihood ratio of 31.73 (indicating a large effect on increasing the probability of predicting miscarriage) and negative likelihood ratio of 0.32. In studies for women with threatened miscarriage (n=5 studies, n=771 women) fetal bradycardia showed further increase in sensitivity (84.18%) for miscarriage prediction. Although there is gestational age dependent variation in the fetal heart rate, a plot

  11. Empirical evidence of the importance of comparative studies of diagnostic test accuracy.

    PubMed

    Takwoingi, Yemisi; Leeflang, Mariska M G; Deeks, Jonathan J

    2013-04-02

    Systematic reviews that "compare" the accuracy of 2 or more tests often include different sets of studies for each test. To investigate the availability of direct comparative studies of test accuracy and to assess whether summary estimates of accuracy differ between meta-analyses of noncomparative and comparative studies. Systematic reviews in any language from the Database of Abstracts of Reviews of Effects and the Cochrane Database of Systematic Reviews from 1994 to October 2012. 1 of 2 assessors selected reviews that evaluated at least 2 tests and identified meta-analyses that included both noncomparative studies and comparative studies. 1 of 3 assessors extracted data about review and study characteristics and test performance. 248 reviews compared test accuracy; of the 6915 studies, 2113 (31%) were comparative. Thirty-six reviews (with 52 meta-analyses) had adequate studies to compare results of noncomparative and comparative studies by using a hierarchical summary receiver-operating characteristic meta-regression model for each test comparison. In 10 meta-analyses, noncomparative studies ranked tests in the opposite order of comparative studies. A total of 25 meta-analyses showed more than a 2-fold discrepancy in the relative diagnostic odds ratio between noncomparative and comparative studies. Differences in accuracy estimates between noncomparative and comparative studies were greater than expected by chance (P < 0.001). A paucity of comparative studies limited exploration of direction in bias. Evidence derived from noncomparative studies often differs from that derived from comparative studies. Robustly designed studies in which all patients receive all tests or are randomly assigned to receive one or other of the tests should be more routinely undertaken and are preferred for evidence to guide test selection. National Institute for Health Research (United Kingdom).

  12. Factoring vs linear modeling in rate estimation: a simulation study of relative accuracy.

    PubMed

    Maldonado, G; Greenland, S

    1998-07-01

    A common strategy for modeling dose-response in epidemiology is to transform ordered exposures and covariates into sets of dichotomous indicator variables (that is, to factor the variables). Factoring tends to increase estimation variance, but it also tends to decrease bias and thus may increase or decrease total accuracy. We conducted a simulation study to examine the impact of factoring on the accuracy of rate estimation. Factored and unfactored Poisson regression models were fit to follow-up study datasets that were randomly generated from 37,500 population model forms that ranged from subadditive to supramultiplicative. In the situations we examined, factoring sometimes substantially improved accuracy relative to fitting the corresponding unfactored model, sometimes substantially decreased accuracy, and sometimes made little difference. The difference in accuracy between factored and unfactored models depended in a complicated fashion on the difference between the true and fitted model forms, the strength of exposure and covariate effects in the population, and the study size. It may be difficult in practice to predict when factoring is increasing or decreasing accuracy. We recommend, therefore, that the strategy of factoring variables be supplemented with other strategies for modeling dose-response.

  13. Meta-analysis of diagnostic accuracy studies in mental health

    PubMed Central

    Takwoingi, Yemisi; Riley, Richard D; Deeks, Jonathan J

    2015-01-01

    Objectives To explain methods for data synthesis of evidence from diagnostic test accuracy (DTA) studies, and to illustrate different types of analyses that may be performed in a DTA systematic review. Methods We described properties of meta-analytic methods for quantitative synthesis of evidence. We used a DTA review comparing the accuracy of three screening questionnaires for bipolar disorder to illustrate application of the methods for each type of analysis. Results The discriminatory ability of a test is commonly expressed in terms of sensitivity (proportion of those with the condition who test positive) and specificity (proportion of those without the condition who test negative). There is a trade-off between sensitivity and specificity, as an increasing threshold for defining test positivity will decrease sensitivity and increase specificity. Methods recommended for meta-analysis of DTA studies --such as the bivariate or hierarchical summary receiver operating characteristic (HSROC) model --jointly summarise sensitivity and specificity while taking into account this threshold effect, as well as allowing for between study differences in test performance beyond what would be expected by chance. The bivariate model focuses on estimation of a summary sensitivity and specificity at a common threshold while the HSROC model focuses on the estimation of a summary curve from studies that have used different thresholds. Conclusions Meta-analyses of diagnostic accuracy studies can provide answers to important clinical questions. We hope this article will provide clinicians with sufficient understanding of the terminology and methods to aid interpretation of systematic reviews and facilitate better patient care. PMID:26446042

  14. Diagnostic accuracy research in glaucoma is still incompletely reported: An application of Standards for Reporting of Diagnostic Accuracy Studies (STARD) 2015.

    PubMed

    Michelessi, Manuele; Lucenteforte, Ersilia; Miele, Alba; Oddone, Francesco; Crescioli, Giada; Fameli, Valeria; Korevaar, Daniël A; Virgili, Gianni

    2017-01-01

    Research has shown a modest adherence of diagnostic test accuracy (DTA) studies in glaucoma to the Standards for Reporting of Diagnostic Accuracy Studies (STARD). We have applied the updated 30-item STARD 2015 checklist to a set of studies included in a Cochrane DTA systematic review of imaging tools for diagnosing manifest glaucoma. Three pairs of reviewers, including one senior reviewer who assessed all studies, independently checked the adherence of each study to STARD 2015. Adherence was analyzed on an individual-item basis. Logistic regression was used to evaluate the effect of publication year and impact factor on adherence. We included 106 DTA studies, published between 2003-2014 in journals with a median impact factor of 2.6. Overall adherence was 54.1% for 3,286 individual rating across 31 items, with a mean of 16.8 (SD: 3.1; range 8-23) items per study. Large variability in adherence to reporting standards was detected across individual STARD 2015 items, ranging from 0 to 100%. Nine items (1: identification as diagnostic accuracy study in title/abstract; 6: eligibility criteria; 10: index test (a) and reference standard (b) definition; 12: cut-off definitions for index test (a) and reference standard (b); 14: estimation of diagnostic accuracy measures; 21a: severity spectrum of diseased; 23: cross-tabulation of the index and reference standard results) were adequately reported in more than 90% of the studies. Conversely, 10 items (3: scientific and clinical background of the index test; 11: rationale for the reference standard; 13b: blinding of index test results; 17: analyses of variability; 18; sample size calculation; 19: study flow diagram; 20: baseline characteristics of participants; 28: registration number and registry; 29: availability of study protocol; 30: sources of funding) were adequately reported in less than 30% of the studies. Only four items showed a statistically significant improvement over time: missing data (16), baseline

  15. Six-minute walk test as a determinant of the functional capacity of children and adolescents with cystic fibrosis: A systematic review.

    PubMed

    Andrade Lima, Cibelle; Dornelas de Andrade, Armèle; Campos, Shirley Lima; Brandão, Daniella Cunha; Mourato, Ianny Pereira; Britto, Murilo Carlos Amorim de

    2018-04-01

    Cystic Fibrosis (CF) is a multisystem disorder. The involvement of the respiratory system is frequent and culminates in dyspnea and exercise intolerance. Functional capacity is an important diagnostic tool, because it reflects the cardiorespiratory status, quality of life and prognosis. This systematic review aims to assess the reproducibility and validity of the six minute walk test (6MWT) to reflect the functional capacity of children and adolescents with cystic fibrosis, and also the correlation between 6MWT and lung function. Searches for articles were performed in eight databases using MeSH/DeCS keywords. A total of 695 articles were found and, after verifying all eligibility criteria, six articles were included for analysis and scoring regarding the methodological quality according to the QUADAS scale (Quality Assessment of Diagnostic Accuracy Studies). All articles had good methodology (QUADAS between 9 and 11 points). The 6MWT is not correlated with lung function. There is a strong indication that the 6MWT is a reproducible test to assess the functional capacity of children and adolescents with CF. The validity assessment could not be reached because the studies included in this systematic review did not use adequate statistical tools to carry out such an evaluation. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Guidance for deriving and presenting percentage study weights in meta-analysis of test accuracy studies.

    PubMed

    Burke, Danielle L; Ensor, Joie; Snell, Kym I E; van der Windt, Danielle; Riley, Richard D

    2018-06-01

    Percentage study weights in meta-analysis reveal the contribution of each study toward the overall summary results and are especially important when some studies are considered outliers or at high risk of bias. In meta-analyses of test accuracy reviews, such as a bivariate meta-analysis of sensitivity and specificity, the percentage study weights are not currently derived. Rather, the focus is on representing the precision of study estimates on receiver operating characteristic plots by scaling the points relative to the study sample size or to their standard error. In this article, we recommend that researchers should also provide the percentage study weights directly, and we propose a method to derive them based on a decomposition of Fisher information matrix. This method also generalises to a bivariate meta-regression so that percentage study weights can also be derived for estimates of study-level modifiers of test accuracy. Application is made to two meta-analyses examining test accuracy: one of ear temperature for diagnosis of fever in children and the other of positron emission tomography for diagnosis of Alzheimer's disease. These highlight that the percentage study weights provide important information that is otherwise hidden if the presentation only focuses on precision based on sample size or standard errors. Software code is provided for Stata, and we suggest that our proposed percentage weights should be routinely added on forest and receiver operating characteristic plots for sensitivity and specificity, to provide transparency of the contribution of each study toward the results. This has implications for the PRISMA-diagnostic test accuracy guidelines that are currently being produced. Copyright © 2017 John Wiley & Sons, Ltd.

  17. Potential diagnostic value of serum p53 antibody for detecting colorectal cancer: A meta-analysis.

    PubMed

    Meng, Rongqin; Wang, Yang; He, Liang; He, Yuanqing; Du, Zedong

    2018-04-01

    Numerous studies have assessed the diagnostic value of serum p53 (s-p53) antibody in patients with colorectal cancer (CRC); however, results remain controversial. The present study aimed to comprehensively and quantitatively summarize the potential diagnostic value of s-p53 antibody in CRC. The present study utilized databases, including PubMed and EmBase, systematically regarding s-p53 antibody diagnosis in CRC, accessed on and prior to 31 July 2016. The quality of all the included studies was assessed using quality assessment of studies of diagnostic accuracy (QUADAS). The result of pooled sensitivity, pooled specificity, positive likelihood ratio (PLR) and negative likelihood ratio (NLR) were analyzed and compared with overall accuracy measures using diagnostic odds ratios (DORs) and area under the curve (AUC) analysis. Publication bias and heterogeneity were also assessed. A total of 11 trials that enrolled a combined 3,392 participants were included in the meta-analysis. Approximately 72.73% (8/11) of the included studies were of high quality (QUADAS score >7), and all were retrospective case-control studies. The pooled sensitivity was 0.19 [95% confidence interval (CI), 0.18-0.21] and pooled specificity was 0.93 (95% CI, 0.92-0.94). Results also demonstrated a PLR of 4.56 (95% CI, 3.27-6.34), NLR of 0.78 (95% CI, 0.71-0.85) and DOR of 6.70 (95% CI, 4.59-9.76). The symmetrical summary receiver operating characteristic curve was 0.73. Furthermore, no evidence of publication bias or heterogeneity was observed in the meta-analysis. Meta-analysis data indicated that s-p53 antibody possesses potential diagnostic value for CRC. However, discrimination power was somewhat limited due to the low sensitivity.

  18. Low clinical diagnostic accuracy of early vs advanced Parkinson disease: clinicopathologic study.

    PubMed

    Adler, Charles H; Beach, Thomas G; Hentz, Joseph G; Shill, Holly A; Caviness, John N; Driver-Dunckley, Erika; Sabbagh, Marwan N; Sue, Lucia I; Jacobson, Sandra A; Belden, Christine M; Dugger, Brittany N

    2014-07-29

    Determine diagnostic accuracy of a clinical diagnosis of Parkinson disease (PD) using neuropathologic diagnosis as the gold standard. Data from the Arizona Study of Aging and Neurodegenerative Disorders were used to determine the predictive value of a clinical PD diagnosis, using 2 clinical diagnostic confidence levels, PossPD (never treated or not clearly responsive) and ProbPD (responsive to medications). Neuropathologic diagnosis was the gold standard. Based on first visit, 9 of 34 (26%) PossPD cases had neuropathologically confirmed PD while 80 of 97 (82%) ProbPD cases had confirmed PD. PD was confirmed in 8 of 15 (53%) ProbPD cases with <5 years of disease duration and 72 of 82 (88%) with ≥5 years of disease duration. Using final diagnosis at time of death, 91 of 107 (85%) ProbPD cases had confirmed PD. Clinical variables that improved diagnostic accuracy were medication response, motor fluctuations, dyskinesias, and hyposmia. Using neuropathologic findings of PD as the gold standard, this study establishes the novel findings of only 26% accuracy for a clinical diagnosis of PD in untreated or not clearly responsive subjects, 53% accuracy in early PD responsive to medication (<5 years' duration), and >85% diagnostic accuracy of longer duration, medication-responsive PD. Caution is needed when interpreting clinical studies of PD, especially studies of early disease that do not have autopsy confirmation. The need for a tissue or other diagnostic biomarker is reinforced. This study provides Class II evidence that a clinical diagnosis of PD identifies patients who will have pathologically confirmed PD with a sensitivity of 88% and specificity of 68%. © 2014 American Academy of Neurology.

  19. The Accuracy and Prognostic Value of Point-of-care Ultrasound for Nephrolithiasis in the Emergency Department: A Systematic Review and Meta-analysis.

    PubMed

    Wong, Charles; Teitge, Braden; Ross, Marshall; Young, Paul; Robertson, Helen Lee; Lang, Eddy

    2018-06-01

    Point-of-care ultrasound (POCUS) has been suggested as an initial investigation in the management of renal colic. Our objectives were: 1) to determine the accuracy of POCUS for the diagnosis of nephrolithiasis and 2) to assess its prognostic value in the management of renal colic. The review protocol was registered to the PROSPERO database (CRD42016035331). An electronic database search of MEDLINE, Embase, and PubMed was conducted utilizing subject headings, keywords, and synonyms that address our research question. Bibliographies of included studies and narrative reviews were manually examined. Studies of adult emergency department patients with renal colic symptoms were included. Any degree of hydronephrosis was considered a positive POCUS finding. Accepted criterion standards were computed tomography evidence of renal stone or hydronephrosis, direct stone visualization, or surgical findings. Screening of abstracts, quality assessment with the QUADAS-2 instrument, and data extraction were performed by two reviewers, with discrepancies resolved by consensus with a third reviewer. Test performance was assessed by pooled sensitivity and specificity, calculated likelihood ratios, and a summary receiver operator curve (SROC). The secondary objective of prognostic value was reported as a narrative summary. The electronic search yielded 627 unique titles. After relevance screening, 26 papers underwent full-text review, and nine articles met all inclusion criteria. Of these, five high-quality studies (N = 1,773) were included in the meta-analysis for diagnostic accuracy and the remaining yielded data on prognostic value. The pooled results for sensitivity and specificity were 70.2% (95% confidence interval [CI] = 67.1%-73.2%) and 75.4% (95% CI = 72.5%-78.2%), respectively. The calculated positive and negative likelihood ratios were 2.85 and 0.39. The SROC generated did not show evidence of a threshold effect. Two of the studies in the meta-analysis found that the

  20. Diagnostic accuracy of tests to detect Hepatitis C antibody: a meta-analysis and review of the literature.

    PubMed

    Tang, Weiming; Chen, Wen; Amini, Ali; Boeras, Debi; Falconer, Jane; Kelly, Helen; Peeling, Rosanna; Varsaneux, Olivia; Tucker, Joseph D; Easterbrook, Philippa

    2017-11-01

    Although direct-acting antivirals can achieve sustained virological response rates greater than 90% in Hepatitis C Virus (HCV) infected persons, at present the majority of HCV-infected individuals remain undiagnosed and therefore untreated. While there are a wide range of HCV serological tests available, there is a lack of formal assessment of their diagnostic performance. We undertook a systematic review and meta-analysis to evaluate he diagnostic accuracy of available rapid diagnostic tests (RDT) and laboratory based EIA assays in detecting antibodies to HCV. We used the PRISMA checklist and Cochrane guidance to develop our search protocol. The search strategy was registered in PROSPERO (CRD42015023567). The search focused on hepatitis C, diagnostic tests, and diagnostic accuracy within eight databases (MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Science Citation Index Expanded, Conference Proceedings Citation Index-Science, SCOPUS, Literatura Latino-Americana e do Caribe em Ciências da Saúde and WHO Global Index Medicus. Studies were included if they evaluated an assay to determine the sensitivity and specificity of HCV antibody (HCV Ab) in humans. Two reviewers independently extracted data and performed a quality assessment of the studies using the QUADAS tool. We pooled test estimates using the DerSimonian-Laird method, by using the software R and RevMan. 5.3. A total of 52 studies were identified that included 52,673 unique test measurements. Based on five studies, the pooled sensitivity and specificity of HCV Ab rapid diagnostic tests (RDTs) were 98% (95% CI 98-100%) and 100% (95% CI 100-100%) compared to an enzyme immunoassay (EIA) reference standard. High HCV Ab RDTs sensitivity and specificity were observed across screening populations (general population, high risk populations, and hospital patients) using different reference standards (EIA, nucleic acid testing, immunoblot). There were insufficient studies to undertake

  1. Using Meta-Analysis to Inform the Design of Subsequent Studies of Diagnostic Test Accuracy

    ERIC Educational Resources Information Center

    Hinchliffe, Sally R.; Crowther, Michael J.; Phillips, Robert S.; Sutton, Alex J.

    2013-01-01

    An individual diagnostic accuracy study rarely provides enough information to make conclusive recommendations about the accuracy of a diagnostic test; particularly when the study is small. Meta-analysis methods provide a way of combining information from multiple studies, reducing uncertainty in the result and hopefully providing substantial…

  2. Alaska national hydrography dataset positional accuracy assessment study

    USGS Publications Warehouse

    Arundel, Samantha; Yamamoto, Kristina H.; Constance, Eric; Mantey, Kim; Vinyard-Houx, Jeremy

    2013-01-01

    Initial visual assessments Wide range in the quality of fit between features in NHD and these new image sources. No statistical analysis has been performed to actually quantify accuracy Determining absolute accuracy is cost prohibitive (must collect independent, well defined test points) Quantitative analysis of relative positional error is feasible.

  3. Ontario multidetector computed tomographic coronary angiography study: field evaluation of diagnostic accuracy.

    PubMed

    Chow, Benjamin J W; Freeman, Michael R; Bowen, James M; Levin, Leslie; Hopkins, Robert B; Provost, Yves; Tarride, Jean-Eric; Dennie, Carole; Cohen, Eric A; Marcuzzi, Dan; Iwanochko, Robert; Moody, Alan R; Paul, Narinder; Parker, John D; O'Reilly, Daria J; Xie, Feng; Goeree, Ron

    2011-06-13

    Computed tomographic coronary angiography (CTCA) has gained clinical acceptance for the detection of obstructive coronary artery disease. Although single-center studies have demonstrated excellent accuracy, multicenter studies have yielded variable results. The true diagnostic accuracy of CTCA in the "real world" remains uncertain. We conducted a field evaluation comparing multidetector CTCA with invasive CA (ICA) to understand CTCA's diagnostic accuracy in a real-world setting. A multicenter cohort study of patients awaiting ICA was conducted between September 2006 and June 2009. All patients had either a low or an intermediate pretest probability for coronary artery disease and underwent CTCA and ICA within 10 days. The results of CTCA and ICA were interpreted visually by local expert observers who were blinded to all clinical data and imaging results. Using a patient-based analysis (diameter stenosis ≥50%) of 169 patients, the sensitivity, specificity, positive predictive value, and negative predictive value were 81.3% (95% confidence interval [CI], 71.0%-89.1%), 93.3% (95% CI, 85.9%-97.5%), 91.6% (95% CI, 82.5%-96.8%), and 84.7% (95% CI, 76.0%-91.2%), respectively; the area under receiver operating characteristic curve was 0.873. The diagnostic accuracy varied across centers (P < .001), with a sensitivity, specificity, positive predictive value, and negative predictive value ranging from 50.0% to 93.2%, 92.0% to 100%, 84.6% to 100%, and 42.9% to 94.7%, respectively. Compared with ICA, CTCA appears to have good accuracy; however, there was variability in diagnostic accuracy across centers. Factors affecting institutional variability need to be better understood before CTCA is universally adopted. Additional real-world evaluations are needed to fully understand the impact of CTCA on clinical care. clinicaltrials.gov Identifier: NCT00371891.

  4. Diagnostic performance of contrast-enhanced spectral mammography: Systematic review and meta-analysis.

    PubMed

    Tagliafico, Alberto Stefano; Bignotti, Bianca; Rossi, Federica; Signori, Alessio; Sormani, Maria Pia; Valdora, Francesca; Calabrese, Massimo; Houssami, Nehmat

    2016-08-01

    To estimate sensitivity and specificity of CESM for breast cancer diagnosis. Systematic review and meta-analysis of the accuracy of CESM in finding breast cancer in highly selected women. We estimated summary receiver operating characteristic curves, sensitivity and specificity according to quality criteria with QUADAS-2. Six hundred four studies were retrieved, 8 of these reporting on 920 patients with 994 lesions, were eligible for inclusion. Estimated sensitivity from all studies was: 0.98 (95% CI: 0.96-1.00). Specificity was estimated from six studies reporting raw data: 0.58 (95% CI: 0.38-0.77). The majority of studies were scored as at high risk of bias due to the very selected populations. CESM has a high sensitivity but very low specificity. The source studies were based on highly selected case series and prone to selection bias. High-quality studies are required to assess the accuracy of CESM in unselected cases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Accuracy of saline contrast sonohysterography in detection of endometrial polyps and submucosal leiomyomas in women of reproductive age with abnormal uterine bleeding: systematic review and meta-analysis.

    PubMed

    Bittencourt, C A; Dos Santos Simões, R; Bernardo, W M; Fuchs, L F P; Soares Júnior, J M; Pastore, A R; Baracat, E C

    2017-07-01

    To analyze the diagnostic accuracy of two- (2D) and three- (3D) dimensional saline contrast sonohysterography (SCSH) in the detection of endometrial polyps and submucosal uterine leiomyomas in women of reproductive age with abnormal uterine bleeding compared with gold standard hysteroscopy. A systematic review of diagnostic studies that compared 2D- and/or 3D-SCSH with hysteroscopy and anatomopathology was conducted according to PRISMA and SEDATE recommendations. The databases MEDLINE, EMBASE and The Cochrane Library were searched electronically using specific terms with no restriction on language or publication year. Quality assessment of included studies was performed using the QUADAS-2 tool. Meta-analysis was performed with the Meta-DiSk program and data presented as forest plots and summary receiver-operating characteristics (SROC) curves. Pooled sensitivity, specificity and positive (LR+) and negative (LR-) likelihood ratios of SCSH in the detection of uterine cavity abnormalities were calculated. A total of 1398 citations were identified and five studies were included in the systematic review and meta-analysis. Pooled sensitivity and specificity of 2D-SCSH in detecting endometrial polyps were 93% (95% CI, 89-96%) and 81% (95% CI, 76-86%), respectively, with pooled LR+ of 5.41 (95% CI, 2.60-11.28) and LR- of 0.10 (95% CI, 0.06-0.17). In the detection of submucosal uterine leiomyomas, pooled sensitivity and specificity were 94% (95% CI, 89-97%) and 81% (95% CI, 76-86%), respectively, with pooled LR+ of 4.25 (95% CI, 2.20-8.21) and LR- of 0.11 (95% CI, 0.05-0.22). 2D-SCSH had good accuracy in detecting endometrial polyps and submucosal uterine leiomyomas, with areas under the SROC curves of 0.97 ± 0.02 and 0.97 ± 0.03, respectively. Studies that analyzed the diagnostic accuracy of 3D-SCSH could not be compared due to high heterogeneity related to menopausal status, type of technique used and primary outcome being investigation of infertility. 2D

  6. The accuracy of endometrial sampling in women with postmenopausal bleeding: a systematic review and meta-analysis.

    PubMed

    van Hanegem, Nehalennia; Prins, Marileen M C; Bongers, Marlies Y; Opmeer, Brent C; Sahota, Daljit Singh; Mol, Ben Willem J; Timmermans, Anne

    2016-02-01

    Postmenopausal bleeding (PMB) can be the first sign of endometrial cancer. In case of thickened endometrium, endometrial sampling is often used in these women. In this systematic review, we studied the accuracy of endometrial sampling for the diagnoses of endometrial cancer, atypical hyperplasia and endometrial disease (endometrial pathology, including benign polyps). We systematically searched the literature for studies comparing the results of endometrial sampling in women with postmenopausal bleeding with two different reference standards: blind dilatation and curettage (D&C) and hysteroscopy with histology. We assessed the quality of the detected studies by the QUADAS-2 tool. For each included study, we calculated the fraction of women in whom endometrial sampling failed. Furthermore, we extracted numbers of cases of endometrial cancer, atypical hyperplasia and endometrial disease that were identified or missed by endometrial sampling. We detected 12 studies reporting on 1029 women with postmenopausal bleeding: five studies with dilatation and curettage (D&C) and seven studies with hysteroscopy as a reference test. The weighted sensitivity of endometrial sampling with D&C as a reference for the diagnosis of endometrial cancer was 100% (range 100-100%) and 92% (71-100) for the diagnosis of atypical hyperplasia. Only one study reported sensitivity for endometrial disease, which was 76%. When hysteroscopy was used as a reference, weighted sensitivities of endometrial sampling were 90% (range 50-100), 82% (range 56-94) and 39% (21-69) for the diagnosis of endometrial cancer, atypical hyperplasia and endometrial disease, respectively. For all diagnosis studied and the reference test used, specificity was 98-100%. The weighted failure rate of endometrial sampling was 11% (range 1-53%), while insufficient samples were found in 31% (range 7-76%). In these women with insufficient or failed samples, an endometrial (pre) cancer was found in 7% (range 0-18%). In women with

  7. Early-Onset Neonatal Sepsis: Still Room for Improvement in Procalcitonin Diagnostic Accuracy Studies

    PubMed Central

    Chiesa, Claudio; Pacifico, Lucia; Osborn, John F.; Bonci, Enea; Hofer, Nora; Resch, Bernhard

    2015-01-01

    Abstract To perform a systematic review assessing accuracy and completeness of diagnostic studies of procalcitonin (PCT) for early-onset neonatal sepsis (EONS) using the Standards for Reporting of Diagnostic Accuracy (STARD) initiative. EONS, diagnosed during the first 3 days of life, remains a common and serious problem. Increased PCT is a potentially useful diagnostic marker of EONS, but reports in the literature are contradictory. There are several possible explanations for the divergent results including the quality of studies reporting the clinical usefulness of PCT in ruling in or ruling out EONS. We systematically reviewed PubMed, Scopus, and the Cochrane Library databases up to October 1, 2014. Studies were eligible for inclusion in our review if they provided measures of PCT accuracy for diagnosing EONS. A data extraction form based on the STARD checklist and adapted for neonates with EONS was used to appraise the quality of the reporting of included studies. We found 18 articles (1998–2014) fulfilling our eligibility criteria which were included in the final analysis. Overall, the results of our analysis showed that the quality of studies reporting diagnostic accuracy of PCT for EONS was suboptimal leaving ample room for improvement. Information on key elements of design, analysis, and interpretation of test accuracy were frequently missing. Authors should be aware of the STARD criteria before starting a study in this field. We welcome stricter adherence to this guideline. Well-reported studies with appropriate designs will provide more reliable information to guide decisions on the use and interpretations of PCT test results in the management of neonates with EONS. PMID:26222858

  8. Using meta-analysis to inform the design of subsequent studies of diagnostic test accuracy.

    PubMed

    Hinchliffe, Sally R; Crowther, Michael J; Phillips, Robert S; Sutton, Alex J

    2013-06-01

    An individual diagnostic accuracy study rarely provides enough information to make conclusive recommendations about the accuracy of a diagnostic test; particularly when the study is small. Meta-analysis methods provide a way of combining information from multiple studies, reducing uncertainty in the result and hopefully providing substantial evidence to underpin reliable clinical decision-making. Very few investigators consider any sample size calculations when designing a new diagnostic accuracy study. However, it is important to consider the number of subjects in a new study in order to achieve a precise measure of accuracy. Sutton et al. have suggested previously that when designing a new therapeutic trial, it could be more beneficial to consider the power of the updated meta-analysis including the new trial rather than of the new trial itself. The methodology involves simulating new studies for a range of sample sizes and estimating the power of the updated meta-analysis with each new study added. Plotting the power values against the range of sample sizes allows the clinician to make an informed decision about the sample size of a new trial. This paper extends this approach from the trial setting and applies it to diagnostic accuracy studies. Several meta-analytic models are considered including bivariate random effects meta-analysis that models the correlation between sensitivity and specificity. Copyright © 2012 John Wiley & Sons, Ltd. Copyright © 2012 John Wiley & Sons, Ltd.

  9. The STARD statement for reporting diagnostic accuracy studies: application to the history and physical examination.

    PubMed

    Simel, David L; Rennie, Drummond; Bossuyt, Patrick M M

    2008-06-01

    The Standards for Reporting of Diagnostic Accuracy (STARD) statement provided guidelines for investigators conducting diagnostic accuracy studies. We reviewed each item in the statement for its applicability to clinical examination diagnostic accuracy research, viewing each discrete aspect of the history and physical examination as a diagnostic test. Nonsystematic review of the STARD statement. Two former STARD Group participants and 1 editor of a journal series on clinical examination research reviewed each STARD item. Suggested interpretations and comments were shared to develop consensus. The STARD Statement applies generally well to clinical examination diagnostic accuracy studies. Three items are the most important for clinical examination diagnostic accuracy studies, and investigators should pay particular attention to their requirements: describe carefully the patient recruitment process, describe participant sampling and address if patients were from a consecutive series, and describe whether the clinicians were masked to the reference standard tests and whether the interpretation of the reference standard test was masked to the clinical examination components or overall clinical impression. The consideration of these and the other STARD items in clinical examination diagnostic research studies would improve the quality of investigations and strengthen conclusions reached by practicing clinicians. The STARD statement provides a very useful framework for diagnostic accuracy studies. The group correctly anticipated that there would be nuances applicable to studies of the clinical examination. We offer guidance that should enhance their usefulness to investigators embarking on original studies of a patient's history and physical examination.

  10. Accuracy of Self-Evaluation in Adults with ADHD: Evidence from a Driving Study

    ERIC Educational Resources Information Center

    Knouse, Laura E.; Bagwell, Catherine L.; Barkley, Russell A.; Murphy, Kevin R.

    2005-01-01

    Research on children with ADHD indicates an association with inaccuracy of self-appraisal. This study examines the accuracy of self-evaluations in clinic-referred adults diagnosed with ADHD. Self-assessments and performance measures of driving in naturalistic settings and on a virtual-reality driving simulator are used to assess accuracy of…

  11. The STARD Statement for Reporting Diagnostic Accuracy Studies: Application to the History and Physical Examination

    PubMed Central

    Rennie, Drummond; Bossuyt, Patrick M. M.

    2008-01-01

    Summary Objective The Standards for Reporting of Diagnostic Accuracy (STARD) statement provided guidelines for investigators conducting diagnostic accuracy studies. We reviewed each item in the statement for its applicability to clinical examination diagnostic accuracy research, viewing each discrete aspect of the history and physical examination as a diagnostic test. Setting Nonsystematic review of the STARD statement. Interventions Two former STARD Group participants and 1 editor of a journal series on clinical examination research reviewed each STARD item. Suggested interpretations and comments were shared to develop consensus. Measurements and Main Results The STARD Statement applies generally well to clinical examination diagnostic accuracy studies. Three items are the most important for clinical examination diagnostic accuracy studies, and investigators should pay particular attention to their requirements: describe carefully the patient recruitment process, describe participant sampling and address if patients were from a consecutive series, and describe whether the clinicians were masked to the reference standard tests and whether the interpretation of the reference standard test was masked to the clinical examination components or overall clinical impression. The consideration of these and the other STARD items in clinical examination diagnostic research studies would improve the quality of investigations and strengthen conclusions reached by practicing clinicians. Conclusions The STARD statement provides a very useful framework for diagnostic accuracy studies. The group correctly anticipated that there would be nuances applicable to studies of the clinical examination. We offer guidance that should enhance their usefulness to investigators embarking on original studies of a patient’s history and physical examination. PMID:18347878

  12. Age Differences in Day-To-Day Speed-Accuracy Tradeoffs: Results from the COGITO Study.

    PubMed

    Ghisletta, Paolo; Joly-Burra, Emilie; Aichele, Stephen; Lindenberger, Ulman; Schmiedek, Florian

    2018-04-23

    We examined adult age differences in day-to-day adjustments in speed-accuracy tradeoffs (SAT) on a figural comparison task. Data came from the COGITO study, with over 100 younger and 100 older adults, assessed for over 100 days. Participants were given explicit feedback about their completion time and accuracy each day after task completion. We applied a multivariate vector auto-regressive model of order 1 to the daily mean reaction time (RT) and daily accuracy scores together, within each age group. We expected that participants adjusted their SAT if the two cross-regressive parameters from RT (or accuracy) on day t-1 of accuracy (or RT) on day t were sizable and negative. We found that: (a) the temporal dependencies of both accuracy and RT were quite strong in both age groups; (b) younger adults showed an effect of their accuracy on day t-1 on their RT on day t, a pattern that was in accordance with adjustments of their SAT; (c) older adults did not appear to adjust their SAT; (d) these effects were partly associated with reliable individual differences within each age group. We discuss possible explanations for older adults' reluctance to recalibrate speed and accuracy on a day-to-day basis.

  13. The accuracy of references in PhD theses: a case study.

    PubMed

    Azadeh, Fereydoon; Vaez, Reyhaneh

    2013-09-01

    Inaccurate references and citations cause confusion, distrust in the accuracy of a report, waste of time and unnecessary financial charges for libraries, information centres and researchers. The aim of the study was to establish the accuracy of article references in PhD theses from the Tehran and Tabriz Universities of Medical Sciences and their compliance with the Vancouver style. We analysed 357 article references in the Tehran and 347 in the Tabriz. Six bibliographic elements were assessed: authors' names, article title, journal title, publication year, volume and page range. Referencing errors were divided into major and minor. Sixty two percent of references in the Tehran and 53% of those in the Tabriz were erroneous. In total, 164 references in the Tehran and 136 in the Tabriz were complete without error. Of 357 reference articles in the Tehran, 34 (9.8%) were in complete accordance with the Vancouver style, compared with none in the Tabriz. Accuracy of referencing did not differ significantly between the two groups, but compliance with the Vancouver style was significantly better in the Tehran. The accuracy of referencing was not satisfactory in both groups, and students need to gain adequate instruction in appropriate referencing methods. © 2013 The authors. Health Information and Libraries Journal © 2013 Health Libraries Group.

  14. Cadastral Positioning Accuracy Improvement: a Case Study in Malaysia

    NASA Astrophysics Data System (ADS)

    Hashim, N. M.; Omar, A. H.; Omar, K. M.; Abdullah, N. M.; Yatim, M. H. M.

    2016-09-01

    Cadastral map is a parcel-based information which is specifically designed to define the limitation of boundaries. In Malaysia, the cadastral map is under authority of the Department of Surveying and Mapping Malaysia (DSMM). With the growth of spatial based technology especially Geographical Information System (GIS), DSMM decided to modernize and reform its cadastral legacy datasets by generating an accurate digital based representation of cadastral parcels. These legacy databases usually are derived from paper parcel maps known as certified plan. The cadastral modernization will result in the new cadastral database no longer being based on single and static parcel paper maps, but on a global digital map. Despite the strict process of the cadastral modernization, this reform has raised unexpected queries that remain essential to be addressed. The main focus of this study is to review the issues that have been generated by this transition. The transformed cadastral database should be additionally treated to minimize inherent errors and to fit them to the new satellite based coordinate system with high positional accuracy. This review result will be applied as a foundation for investigation to study the systematic and effectiveness method for Positional Accuracy Improvement (PAI) in cadastral database modernization.

  15. Evaluating radiographers' diagnostic accuracy in screen-reading mammograms: what constitutes a quality study?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Debono, Josephine C, E-mail: josephine.debono@bci.org.au; Poulos, Ann E; Westmead Breast Cancer Institute, Westmead, New South Wales

    The aim of this study was to first evaluate the quality of studies investigating the diagnostic accuracy of radiographers as mammogram screen-readers and then to develop an adapted tool for determining the quality of screen-reading studies. A literature search was used to identify relevant studies and a quality evaluation tool constructed by combining the criteria for quality of Whiting, Rutjes, Dinnes et al. and Brealey and Westwood. This constructed tool was then applied to the studies and subsequently adapted specifically for use in evaluating quality in studies investigating diagnostic accuracy of screen-readers. Eleven studies were identified and the constructed toolmore » applied to evaluate quality. This evaluation resulted in the identification of quality issues with the studies such as potential for bias, applicability of results, study conduct, reporting of the study and observer characteristics. An assessment of the applicability and relevance of the tool for this area of research resulted in adaptations to the criteria and the development of a tool specifically for evaluating diagnostic accuracy in screen-reading. This tool, with further refinement and rigorous validation can make a significant contribution to promoting well-designed studies in this important area of research and practice.« less

  16. Systematic review of discharge coding accuracy

    PubMed Central

    Burns, E.M.; Rigby, E.; Mamidanna, R.; Bottle, A.; Aylin, P.; Ziprin, P.; Faiz, O.D.

    2012-01-01

    Introduction Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain. Methods Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries. Results Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3–92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3–94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7–88.7%). There was considerable variation in accuracy rates between studies (50.5–97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3–92.1%) to 96.0% (IQR: 89.3–96.3), P= 0.020. Conclusion Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making. PMID:21795302

  17. Dynamic Development of Complexity and Accuracy: A Case Study in Second Language Academic Writing

    ERIC Educational Resources Information Center

    Rosmawati

    2014-01-01

    This paper reports on the development of complexity and accuracy in English as a Second Language (ESL) academic writing. Although research into complexity and accuracy development in second language (L2) writing has been well established, few studies have assumed the multidimensionality of these two constructs (Norris & Ortega, 2009) or…

  18. One process is not enough! A speed-accuracy tradeoff study of recognition memory.

    PubMed

    Boldini, Angela; Russo, Riccardo; Avons, S E

    2004-04-01

    Speed-accuracy tradeoff (SAT) methods have been used to contrast single- and dual-process accounts of recognition memory. In these procedures, subjects are presented with individual test items and are required to make recognition decisions under various time constraints. In this experiment, we presented word lists under incidental learning conditions, varying the modality of presentation and level of processing. At test, we manipulated the interval between each visually presented test item and a response signal, thus controlling the amount of time available to retrieve target information. Study-test modality match had a beneficial effect on recognition accuracy at short response-signal delays (< or =300 msec). Conversely, recognition accuracy benefited more from deep than from shallow processing at study only at relatively long response-signal delays (> or =300 msec). The results are congruent with views suggesting that both fast familiarity and slower recollection processes contribute to recognition memory.

  19. A systematic review of diagnostic criteria for psoriasis in adults and children: evidence from studies with a primary aim to develop or validate diagnostic criteria.

    PubMed

    Burden-Teh, E; Phillips, R C; Thomas, K S; Ratib, S; Grindlay, D; Murphy, R

    2017-11-06

    The diagnosis of psoriasis in adults and children is made clinically, for both patient management and the selection of participants in research. Diagnostic criteria provide a structure for clinical assessment, which in turn helps standardize patient recruitment into clinical trials and case definitions in observational studies. The aim of this systematic review was to identify and critically appraise the published studies to date that had a primary research aim to develop or validate diagnostic criteria for psoriasis. A search of Ovid MEDLINE and Ovid Embase was conducted in October 2016. The primary objective was to record the sensitivity and specificity of diagnostic criteria for psoriasis. Secondary objectives included diagnostic recommendations, applicability to children and study characteristics. Diagnostic accuracy studies were critically appraised for risk of bias using the QUADAS-2 tool. Twenty-three studies met the inclusion criteria. None detailed clinical examination-based diagnostic criteria. The included criteria varied from genetic and molecular diagnostic models to skin imaging, histopathology, and questionnaire-based, computer-aided and traditional Chinese medicine criteria. High sensitivity and specificity (> 90%) were reported in many studies. However, the study authors often did not specify how the criteria would be used clinically or in research. This review identified studies with varying risk of bias, and due to each study developing separate criteria meta-analysis was not possible. Clinical examination-based diagnostic criteria are currently lacking for psoriasis. Future research could follow an international collaborative approach and employ study designs allowing high-quality diagnostic accuracy testing. Existing and newly developed criteria require validation. © 2017 British Association of Dermatologists.

  20. Validation studies in forensic odontology - Part 1: Accuracy of radiographic matching.

    PubMed

    Page, Mark; Lain, Russell; Kemp, Richard; Taylor, Jane

    2018-05-01

    As part of a series of studies aimed at validating techniques in forensic odontology, this study aimed to validate the accuracy of ante-mortem (AM)/postmortem (PM) radiographic matching by dentists and forensic odontologists. This study used a web-based interface with 50 pairs of AM and PM radiographs from real casework, at varying degrees of difficulty. Participants were shown both radiographs as a pair and initially asked to decide if they represented the same individual using a yes/no binary choice forced-decision. Participants were asked to assess their level of confidence in their decision, and to make a conclusion using one of the ABFO (American Board of Forensic Odontology), INTERPOL (International Criminal Police Organisation) and DVISys™ (DVI System International, Plass Data Software) identification scale degrees. The mean false-positive rate using the binary choice scale was 12%. Overall accuracy was 89% using this model, however, 13% of participants scored below 80%. Only 25% of participants accurately answered yes or no >90% of the time, with no individual making the correct yes/no decision for all 50 pairs of radiographs. Non-odontologists (lay participants) scored poorly, with a mean accuracy of only 60%. Use of the graded ABFO, DVISYS and INTERPOL scales resulted in general improvements in performance, with the false-positive and false-negative rates falling to approximately 2% overall. Inter-examiner agreement in assigning scale degrees was good (ICC=0.64), however there was little correlation between confidence and both accuracy or agreement among practitioners. These results suggest that use of a non-binary scale is supported over a match/non-match call as it reduces the frequency of false positives and negatives. The use of the terms "possible" and "insufficient information" in the same scale appears to create confusion, reducing inter-examiner agreement. The lack of agreement between higher-performing and lower-performing groups suggests that

  1. Adjusting for partial verification or workup bias in meta-analyses of diagnostic accuracy studies.

    PubMed

    de Groot, Joris A H; Dendukuri, Nandini; Janssen, Kristel J M; Reitsma, Johannes B; Brophy, James; Joseph, Lawrence; Bossuyt, Patrick M M; Moons, Karel G M

    2012-04-15

    A key requirement in the design of diagnostic accuracy studies is that all study participants receive both the test under evaluation and the reference standard test. For a variety of practical and ethical reasons, sometimes only a proportion of patients receive the reference standard, which can bias the accuracy estimates. Numerous methods have been described for correcting this partial verification bias or workup bias in individual studies. In this article, the authors describe a Bayesian method for obtaining adjusted results from a diagnostic meta-analysis when partial verification or workup bias is present in a subset of the primary studies. The method corrects for verification bias without having to exclude primary studies with verification bias, thus preserving the main advantages of a meta-analysis: increased precision and better generalizability. The results of this method are compared with the existing methods for dealing with verification bias in diagnostic meta-analyses. For illustration, the authors use empirical data from a systematic review of studies of the accuracy of the immunohistochemistry test for diagnosis of human epidermal growth factor receptor 2 status in breast cancer patients.

  2. Feasibility and Accuracy of Digitizing Edentulous Maxillectomy Defects: A Comparative Study.

    PubMed

    Elbashti, Mahmoud E; Hattori, Mariko; Patzelt, Sebastian Bm; Schulze, Dirk; Sumita, Yuka I; Taniguchi, Hisashi

    The aim of this study was to evaluate the feasibility and accuracy of using an intraoral scanner to digitize edentulous maxillectomy defects. A total of 20 maxillectomy models with two defect types were digitized using cone beam computed tomography. Conventional and digital impressions were made using silicone impression material and a laboratory optical scanner as well as a chairside intraoral scanner. The 3D datasets were analyzed using 3D evaluation software. Two-way analysis of variance revealed no interaction between defect types and impression methods, and the accuracy of the impression methods was significantly different (P = .0374). Digitizing edentulous maxillectomy defect models using a chairside intraoral scanner appears to be feasible and accurate.

  3. The diagnostic value of cerebrospinal fluid lactate for post-neurosurgical bacterial meningitis: a meta-analysis.

    PubMed

    Xiao, Xiong; Zhang, Yang; Zhang, Liwei; Kang, Peng; Ji, Nan

    2016-09-13

    Bacterial meningitis is not rare in post-neurosurgical patients. If patients are not treated promptly, the mortality rate can reach 20 to 50 %. The concentration of cerebrospinal fluid (CSF) lactate has been reported to be helpful in the diagnosis of bacterial meningitis; however, no systematic evaluations have investigated CSF from a postoperative perspective. In this study, we performed a systematic evaluation and meta-analysis of the efficacy of using CSF lactate concentrations in the diagnosis of post-neurosurgical bacterial meningitis. We retrieved studies that investigated the diagnostic value of CSF lactate for the diagnosis of post-neurosurgical bacterial meningitis by searching PubMed, EBSCO, the Cochrane Library and ClinicalTrials.gov. All these databases were searched from inception to November 2015. We used Quality Assessment of Diagnostic Accuracy Studies (QUADAS), a tool for the quality assessment of diagnostic accuracy, to evaluate the quality of the included studies. The Meta-DiSc 1.4 and Review Manager 5.3 software programs were used to analyze the included studies. Forest plots and summary receiver operating characteristics (SROC) curves were also drawn. Five studies, involving a total of 404 post-neurosurgical patients, were selected from 1,672 articles according to the inclusion criteria. The quality of the five included studies was assessed using QUADAS, and the related results are presented in tables. The meta-analysis revealed the following diagnostic values regarding CSF lactate for post-neurosurgical bacterial meningitis: a pooled sensitivity of 0.92 (95 % CI 0.85-0.96), a pooled specificity of 0.88 (95 % CI 0.84-0.92 with significant heterogeneity), a diagnostic odds ratio of 83.09 (95 % CI 36.83-187.46), an area under the curve (AUCSROC) of 0.9601, an SE(AUC) of 0.0122, a Q* of 0.9046 and an SE(Q*) of 0.0179. The meta-analysis indicated that the CSF lactate concentration has relatively high sensitivity and specificity for the

  4. Physical examination tests for screening and diagnosis of cervicogenic headache: A systematic review.

    PubMed

    Rubio-Ochoa, J; Benítez-Martínez, J; Lluch, E; Santacruz-Zaragozá, S; Gómez-Contreras, P; Cook, C E

    2016-02-01

    It has been suggested that differential diagnosis of headaches should consist of a robust subjective examination and a detailed physical examination of the cervical spine. Cervicogenic headache (CGH) is a form of headache that involves referred pain from the neck. To our knowledge, no studies have summarized the reliability and diagnostic accuracy of physical examination tests for CGH. The aim of this study was to summarize the reliability and diagnostic accuracy of physical examination tests used to diagnose CGH. A systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed in four electronic databases (MEDLINE, Web of Science, Embase and Scopus). Full text reports concerning physical tests for the diagnosis of CGH which reported the clinometric properties for assessment of CGH, were included and screened for methodological quality. Quality Appraisal for Reliability Studies (QAREL) and Quality Assessment of Studies of Diagnostic Accuracy (QUADAS-2) scores were completed to assess article quality. Eight articles were retrieved for quality assessment and data extraction. Studies investigating diagnostic reliability of physical examination tests for CGH scored poorer on methodological quality (higher risk of bias) than those of diagnostic accuracy. There is sufficient evidence showing high levels of reliability and diagnostic accuracy of the selected physical examination tests for the diagnosis of CGH. The cervical flexion-rotation test (CFRT) exhibited both the highest reliability and the strongest diagnostic accuracy for the diagnosis of CGH. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Concordance and Reliability of Photogrammetric Protocols for Measuring the Cervical Lordosis Angle: A Systematic Review of the Literature.

    PubMed

    de Albuquerque, Priscila Maria Nascimento Martins; de Alencar, Geisa Guimarães; de Oliveira, Daniela Araújo; de Siqueira, Gisela Rocha

    2018-01-01

    The aim of this study was to examine and interpret the concordance, accuracy, and reliability of photogrammetric protocols available in the literature for evaluating cervical lordosis in an adult population aged 18 to 59 years. A systematic search of 6 electronic databases (MEDLINE via PubMed, LILACS, CINAHL, Scopus, ScienceDirect, and Web of Science) located studies that assessed the reliability and/or concordance and/or accuracy of photogrammetric protocols for evaluating cervical lordosis, compared with radiography. Articles published through April 2016 were selected. Two independent reviewers used a critical appraisal tool (QUADAS and QAREL) to assess the quality of the selected studies. Two studies were included in the review and had high levels of reliability (intraclass correlation coefficient: 0.974-0.98). Only 1 study assessed the concordance between the methods, which was calculated using Pearson's correlation coefficient. To date, the accuracy of photogrammetry has not been investigated thoroughly. We encountered no study in the literature that investigated the accuracy of photogrammetry in diagnosing hyperlordosis of cervical spine. However, both current studies report high levels of intra- and interrater reliability. To increase the level of evidence of photogrammetry in the evaluation of cervical lordosis, it is necessary to conduct further studies using a larger sample to increase the external validity of the findings. Copyright © 2018. Published by Elsevier Inc.

  6. Preliminary study of GPS orbit determination accuracy achievable from worldwide tracking data

    NASA Technical Reports Server (NTRS)

    Larden, D. R.; Bender, P. L.

    1982-01-01

    The improvement in the orbit accuracy if high accuracy tracking data from a substantially larger number of ground stations is available was investigated. Observations from 20 ground stations indicate that 20 cm or better accuracy can be achieved for the horizontal coordinates of the GPS satellites. With this accuracy, the contribution to the error budget for determining 1000 km baselines by GPS geodetic receivers would be only about 1 cm.

  7. Matters of accuracy and conventionality: prior accuracy guides children's evaluations of others' actions.

    PubMed

    Scofield, Jason; Gilpin, Ansley Tullos; Pierucci, Jillian; Morgan, Reed

    2013-03-01

    Studies show that children trust previously reliable sources over previously unreliable ones (e.g., Koenig, Clément, & Harris, 2004). However, it is unclear from these studies whether children rely on accuracy or conventionality to determine the reliability and, ultimately, the trustworthiness of a particular source. In the current study, 3- and 4-year-olds were asked to endorse and imitate one of two actors performing an unfamiliar action, one actor who was unconventional but successful and one who was conventional but unsuccessful. These data demonstrated that children preferred endorsing and imitating the unconventional but successful actor. Results suggest that when the accuracy and conventionality of a source are put into conflict, children may give priority to accuracy over conventionality when estimating the source's reliability and, ultimately, when deciding who to trust.

  8. Diagnostic Accuracy of History, Physical Examination, Laboratory Tests, and Point-of-care Ultrasound for Pediatric Acute Appendicitis in the Emergency Department: A Systematic Review and Meta-analysis.

    PubMed

    Benabbas, Roshanak; Hanna, Mark; Shah, Jay; Sinert, Richard

    2017-05-01

    Acute appendicitis (AA) is the most common surgical emergency in children. Accurate and timely diagnosis is crucial but challenging due to atypical presentations and the inherent difficulty of obtaining a reliable history and physical examination in younger children. The aim of this study was to determine the utility of history, physical examination, laboratory tests, Pediatric Appendicitis Score (PAS) and Emergency Department Point-of-Care Ultrasound (ED-POCUS) in the diagnosis of AA in ED pediatric patients. We performed a systematic review and meta-analysis and used a test-treatment threshold model to identify diagnostic findings that could rule in/out AA and obviate the need for further imaging studies, specifically computed tomography (CT) scan, magnetic resonance imaging (MRI), and radiology department ultrasound (RUS). We searched PubMed, EMBASE, and SCOPUS up to October 2016 for studies on ED pediatric patients with abdominal pain. Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2) was used to evaluate the quality and applicability of included studies. Positive and negative likelihood ratios (LR+ and LR-) for diagnostic modalities were calculated and when appropriate data was pooled using Meta-DiSc. Based on the available literature on the test characteristics of different imaging modalities and applying the Pauker-Kassirer method we developed a test-treatment threshold model. Twenty-one studies were included encompassing 8,605 patients with weighted AA prevalence of 39.2%. Studies had variable quality using the QUADAS-2 tool with most studies at high risk of partial verification bias. We divided studies based on their inclusion criteria into two groups of "undifferentiated abdominal pain" and abdominal pain "suspected of AA." In patients with undifferentiated abdominal pain, history of "pain migration to right lower quadrant (RLQ)" (LR+ = 4.81, 95% confidence interval [CI] = 3.59-6.44) and presence of "cough/hop pain" in the physical

  9. Continuous Glucose Monitoring and Trend Accuracy

    PubMed Central

    Gottlieb, Rebecca; Le Compte, Aaron; Chase, J. Geoffrey

    2014-01-01

    Continuous glucose monitoring (CGM) devices are being increasingly used to monitor glycemia in people with diabetes. One advantage with CGM is the ability to monitor the trend of sensor glucose (SG) over time. However, there are few metrics available for assessing the trend accuracy of CGM devices. The aim of this study was to develop an easy to interpret tool for assessing trend accuracy of CGM data. SG data from CGM were compared to hourly blood glucose (BG) measurements and trend accuracy was quantified using the dot product. Trend accuracy results are displayed on the Trend Compass, which depicts trend accuracy as a function of BG. A trend performance table and Trend Index (TI) metric are also proposed. The Trend Compass was tested using simulated CGM data with varying levels of error and variability, as well as real clinical CGM data. The results show that the Trend Compass is an effective tool for differentiating good trend accuracy from poor trend accuracy, independent of glycemic variability. Furthermore, the real clinical data show that the Trend Compass assesses trend accuracy independent of point bias error. Finally, the importance of assessing trend accuracy as a function of BG level is highlighted in a case example of low and falling BG data, with corresponding rising SG data. This study developed a simple to use tool for quantifying trend accuracy. The resulting trend accuracy is easily interpreted on the Trend Compass plot, and if required, performance table and TI metric. PMID:24876437

  10. Study on the position accuracy of a mechanical alignment system

    NASA Astrophysics Data System (ADS)

    Cai, Yimin

    In this thesis, we investigated the precision level and established the baseline achieved by a mechanical alignment system using datums and reference surfaces. The factors which affect the accuracy of mechanical alignment system were studied and methodology was developed to suppress these factors so as to reach its full potential precision. In order to characterize the mechanical alignment system quantitatively, a new optical position monitoring system by using quadrant detectors has been developed in this thesis, it can monitor multi-dimensional degrees of mechanical workpieces in real time with high precision. We studied the noise factors inside the system and optimized the optical system. Based on the fact that one of the major limiting noise factors is the shifting of the laser beam, a noise cancellation technique has been developed successfully to suppress this noise, the feasibility of an ultra high resolution (<20 A) for displacement monitoring has been demonstrated. Using the optical position monitoring system, repeatability experiment of the mechanical alignment system has been conducted on different kinds of samples including steel, aluminum, glass and plastics with the same size 100mm x 130mm. The alignment accuracy was studied quantitatively rather than qualitatively before. In a controlled environment, the alignment precision can be improved 5 folds by securing the datum without other means of help. The alignment accuracy of an aluminum workpiece having reference surface by milling is about 3 times better than by shearing. Also we have found that sample material can have fairly significant effect on the alignment precision of the system. Contamination trapped between the datum and reference surfaces in mechanical alignment system can cause errors of registration or reduce the level of manufacturing precision. In the thesis, artificial and natural dust particles were used to simulate the real situations and their effects on system precision have been

  11. Preliminary study of GPS orbit determination accuracy achievable from worldwide tracking data

    NASA Technical Reports Server (NTRS)

    Larden, D. R.; Bender, P. L.

    1983-01-01

    The improvement in the orbit accuracy if high accuracy tracking data from a substantially larger number of ground stations is available was investigated. Observations from 20 ground stations indicate that 20 cm or better accuracy can be achieved for the horizontal coordinates of the GPS satellites. With this accuracy, the contribution to the error budget for determining 1000 km baselines by GPS geodetic receivers would be only about 1 cm. Previously announced in STAR as N83-14605

  12. PAX1 and SOX1 methylation as an initial screening method for cervical cancer: a meta-analysis of individual studies in Asians

    PubMed Central

    Cui, Zhaolei; Xiao, Zhenzhou; Hu, Minhua; Jiang, Chuanhui; Lin, Yingying; Chen, Yansong

    2016-01-01

    Background Epigenetic alterations of gene or DNA methylation have been highlighted as promising biomarkers for early cervical cancer screening. Herein, we evaluated the diagnostic performance of paired boxed gene 1 (PAX1) and sex determining region Y-box 1 (SOX1) methylation for cervical cancer detection. Methods Eligible studies were retrieved by searching the electronic databases. Study quality was assessed according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) checklist. The bivariate meta-analysis model was employed to plot the summary receiver operator characteristic (SROC) curve using Stata 12.0 software. Results The pooled sensitivity of PAX1 methylation was estimated to be 0.73 [95% confidence interval (CI): 0.70–0.75] in differentiating patients with HSIL (high-grade squamous intraepithelial lesion) or CIN3+ (cervical intraepithelial neoplasia type III/worse) or cervical cancer from normal individuals, corresponding to a specificity of 0.87 (95% CI: 0.85–0.89) and area under the curve (AUC) of 0.91. The SOX1 methylation test yielded an AUC of 0.82, under which, the pooled sensitivity was 0.71 (95% CI: 0.67–0.74) and specificity was 0.64 (95% CI: 0.61–0.67). Notably, the stratified analysis suggested that combing parallel testing of PAX1 methylation and human papillomavirus (HPV) DNA (AUC, sensitivity, and specificity of 0.89, 0.75, and 0.81, respectively) achieved higher accuracy than single HPV DNA testing (AUC, sensitivity, and specificity of 0.77, 0.81, and 0.70, respectively). Conclusions PAX1 or SOX1 methylation has a prospect to be an auxiliary biomarker for cervical cancer screening, and parallel testing of PAX1 methylation and HPV DNA in cervical swabs confers an improved diagnostic accuracy than single HPV DNA testing. PMID:27826568

  13. Grading evidence from test accuracy studies: what makes it challenging compared with the grading of effectiveness studies?

    PubMed

    Rogozińska, Ewelina; Khan, Khalid

    2017-06-01

    Guideline panels need to process a sizeable amount of information to issue a decision on whether to recommend a health technology or not. Grading of Recommendations Assessment, Development, and Evaluation (GRADE) is being frequently applied in guideline development to facilitate this task, typically for the synthesis of effectiveness research. Questions regarding the accuracy of medical tests are ubiquitous, and they temporally precede questions about therapy. However, literature summarising the experience of applying GRADE approach to accuracy evaluations is not as rich as one for effectiveness evidence. Type of study design (cross-sectional), two-dimensional nature of the performance measures (sensitivity and specificity), propensity towards a higher level of between-study heterogeneity, poor reporting of quality features and uncertainty about how best to assess for publication bias among other features make this task challenging. This article presents solutions adopted to addresses above challenges for judicious estimation of the strength of test accuracy evidence used to inform evidence syntheses for guideline development. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  14. Ground Truth Sampling and LANDSAT Accuracy Assessment

    NASA Technical Reports Server (NTRS)

    Robinson, J. W.; Gunther, F. J.; Campbell, W. J.

    1982-01-01

    It is noted that the key factor in any accuracy assessment of remote sensing data is the method used for determining the ground truth, independent of the remote sensing data itself. The sampling and accuracy procedures developed for nuclear power plant siting study are described. The purpose of the sampling procedure was to provide data for developing supervised classifications for two study sites and for assessing the accuracy of that and the other procedures used. The purpose of the accuracy assessment was to allow the comparison of the cost and accuracy of various classification procedures as applied to various data types.

  15. The neglected tool in the Bayesian ecologist's shed: a case study testing informative priors' effect on model accuracy

    PubMed Central

    Morris, William K; Vesk, Peter A; McCarthy, Michael A; Bunyavejchewin, Sarayudh; Baker, Patrick J

    2015-01-01

    Despite benefits for precision, ecologists rarely use informative priors. One reason that ecologists may prefer vague priors is the perception that informative priors reduce accuracy. To date, no ecological study has empirically evaluated data-derived informative priors' effects on precision and accuracy. To determine the impacts of priors, we evaluated mortality models for tree species using data from a forest dynamics plot in Thailand. Half the models used vague priors, and the remaining half had informative priors. We found precision was greater when using informative priors, but effects on accuracy were more variable. In some cases, prior information improved accuracy, while in others, it was reduced. On average, models with informative priors were no more or less accurate than models without. Our analyses provide a detailed case study on the simultaneous effect of prior information on precision and accuracy and demonstrate that when priors are specified appropriately, they lead to greater precision without systematically reducing model accuracy. PMID:25628867

  16. The neglected tool in the Bayesian ecologist's shed: a case study testing informative priors' effect on model accuracy.

    PubMed

    Morris, William K; Vesk, Peter A; McCarthy, Michael A; Bunyavejchewin, Sarayudh; Baker, Patrick J

    2015-01-01

    Despite benefits for precision, ecologists rarely use informative priors. One reason that ecologists may prefer vague priors is the perception that informative priors reduce accuracy. To date, no ecological study has empirically evaluated data-derived informative priors' effects on precision and accuracy. To determine the impacts of priors, we evaluated mortality models for tree species using data from a forest dynamics plot in Thailand. Half the models used vague priors, and the remaining half had informative priors. We found precision was greater when using informative priors, but effects on accuracy were more variable. In some cases, prior information improved accuracy, while in others, it was reduced. On average, models with informative priors were no more or less accurate than models without. Our analyses provide a detailed case study on the simultaneous effect of prior information on precision and accuracy and demonstrate that when priors are specified appropriately, they lead to greater precision without systematically reducing model accuracy.

  17. Data accuracy assessment using enterprise architecture

    NASA Astrophysics Data System (ADS)

    Närman, Per; Holm, Hannes; Johnson, Pontus; König, Johan; Chenine, Moustafa; Ekstedt, Mathias

    2011-02-01

    Errors in business processes result in poor data accuracy. This article proposes an architecture analysis method which utilises ArchiMate and the Probabilistic Relational Model formalism to model and analyse data accuracy. Since the resources available for architecture analysis are usually quite scarce, the method advocates interviews as the primary data collection technique. A case study demonstrates that the method yields correct data accuracy estimates and is more resource-efficient than a competing sampling-based data accuracy estimation method.

  18. Accuracy and reliability of self-reported weight and height in the Sister Study

    PubMed Central

    Lin, Cynthia J; DeRoo, Lisa A; Jacobs, Sara R; Sandler, Dale P

    2012-01-01

    Objective To assess accuracy and reliability of self-reported weight and height and identify factors associated with reporting accuracy. Design Analysis of self-reported and measured weight and height from participants in the Sister Study (2003–2009), a nationwide cohort of 50,884 women aged 35–74 in the United States with a sister with breast cancer. Setting Weight and height were reported via computer-assisted telephone interview (CATI) and self-administered questionnaires, and measured by examiners. Subjects Early enrollees in the Sister Study. There were 18,639 women available for the accuracy analyses and 13,316 for the reliability analyses. Results Using weighted kappa statistics, comparisons were made between CATI responses and examiner measures to assess accuracy and CATI and questionnaire responses to assess reliability. Polytomous logistic regression evaluated factors associated with over- or under-reporting. Compared to measured values, agreement was 96% for reported height (±1 inch; weighted kappa 0.84) and 67% for weight (±3 pounds; weighted kappa 0.92). Obese women [body mass index (BMI) ≥30 kg/m2)] were more likely than normal weight women to under-report weight by ≥5% and underweight women (BMI <18.5 kg/m2) were more likely to over-report. Among normal and overweight women (18.5 kgm2≤ BMI <30 kgm2), weight cycling and lifetime weight difference ≥50 pounds were associated with over-reporting. Conclusions U.S. women in the Sister Study were reasonably reliable and accurate in reporting weight and height. Women with normal-range BMI reported most accurately. Overweight and obese women and those with weight fluctuations were less accurate, but even among obese women, few under-reported their weight by >10%. PMID:22152926

  19. Systematic review of the accuracy of dual-source cardiac CT for detection of arterial stenosis in difficult to image patient groups.

    PubMed

    Westwood, Marie E; Raatz, Heike D I; Misso, Kate; Burgers, Laura; Redekop, Ken; Lhachimi, Stefan K; Armstrong, Nigel; Kleijnen, Jos

    2013-05-01

    To assess the diagnostic performance of dual-source cardiac (DSC) computed tomography (CT) newer-generation CT instruments for identifying anatomically significant coronary artery disease (CAD) in patients who are difficult to image by using 64-section CT. A literature search comprised bibliographic databases (January 1, 2000, to March 22, 2011, with a pragmatic update on September 6, 2012), trial registries, and conference proceedings. Only studies using invasive coronary angiography as reference standard were included. Risk of bias was assessed (QUADAS-2). Results were stratified according to patient group on the basis of clinical characteristics. Summary estimates of sensitivity and specificity of DSC CT for detecting 50% or greater arterial stenosis were calculated by using a bivariate summary receiver operating characteristic or random-effects model. Twenty-five studies reported accuracy of DSC CT for diagnosing CAD in difficult to image patients; in 22 studies, one of two CT units of the same manufacturer (Somatom Definition or Somatom Definition Flash) was used, and in the remaining three, a different CT unit of another manufacturer (Aquilion One) was used. The pooled, per-patient estimates of sensitivity were 97.7% (95% confidence interval [CI]: 88.0%, 99.9%) and 97.7% (95% CI: 93.2%, 99.3%) for patients with arrhythmias and high heart rates, respectively. The corresponding pooled estimates of specificity were 81.7% (95% CI: 71.6%, 89.4%) and 86.3% (95% CI: 80.2%, 90.7%), respectively. All data were acquired by using Somatom Definition. In two studies with Somatom and one study with Aquilion One, sensitivity estimates of 90% or greater were reported in patients with previous stent implantations; specificities were 81.7% and 89.5% for Somatom and 81.0% for Aquilion One. In patients with high coronary calcium scores, previous bypass grafts, or obesity, only per-segment or per-artery data were available. Sensitivity estimates remained high (>90% in all but one

  20. Verification and classification bias interactions in diagnostic test accuracy studies for fine-needle aspiration biopsy.

    PubMed

    Schmidt, Robert L; Walker, Brandon S; Cohen, Michael B

    2015-03-01

    Reliable estimates of accuracy are important for any diagnostic test. Diagnostic accuracy studies are subject to unique sources of bias. Verification bias and classification bias are 2 sources of bias that commonly occur in diagnostic accuracy studies. Statistical methods are available to estimate the impact of these sources of bias when they occur alone. The impact of interactions when these types of bias occur together has not been investigated. We developed mathematical relationships to show the combined effect of verification bias and classification bias. A wide range of case scenarios were generated to assess the impact of bias components and interactions on total bias. Interactions between verification bias and classification bias caused overestimation of sensitivity and underestimation of specificity. Interactions had more effect on sensitivity than specificity. Sensitivity was overestimated by at least 7% in approximately 6% of the tested scenarios. Specificity was underestimated by at least 7% in less than 0.1% of the scenarios. Interactions between verification bias and classification bias create distortions in accuracy estimates that are greater than would be predicted from each source of bias acting independently. © 2014 American Cancer Society.

  1. Test expectancy affects metacomprehension accuracy.

    PubMed

    Thiede, Keith W; Wiley, Jennifer; Griffin, Thomas D

    2011-06-01

    Theory suggests that the accuracy of metacognitive monitoring is affected by the cues used to judge learning. Researchers have improved monitoring accuracy by directing attention to more appropriate cues; however, this is the first study to more directly point students to more appropriate cues using instructions regarding tests and practice tests. The purpose of the present study was to examine whether the accuracy metacognitive monitoring was affected by the nature of the test expected. Students (N= 59) were randomly assigned to one of two test expectancy groups (memory vs. inference). Then after reading texts, judging learning, completed both memory and inference tests. Test performance and monitoring accuracy were superior when students received the kind of test they had been led to expect rather than the unexpected test. Tests influence students' perceptions of what constitutes learning. Our findings suggest that this could affect how students prepare for tests and how they monitoring their own learning. ©2010 The British Psychological Society.

  2. Methods specification for diagnostic test accuracy studies in fine-needle aspiration cytology: a survey of reporting practice.

    PubMed

    Schmidt, Robert L; Factor, Rachel E; Affolter, Kajsa E; Cook, Joshua B; Hall, Brian J; Narra, Krishna K; Witt, Benjamin L; Wilson, Andrew R; Layfield, Lester J

    2012-01-01

    Diagnostic test accuracy (DTA) studies on fine-needle aspiration cytology (FNAC) often show considerable variability in diagnostic accuracy between study centers. Many factors affect the accuracy of FNAC. A complete description of the testing parameters would help make valid comparisons between studies and determine causes of performance variation. We investigated the manner in which test conditions are specified in FNAC DTA studies to determine which parameters are most commonly specified and the frequency with which they are specified and to see whether there is significant variability in reporting practice. We identified 17 frequently reported test parameters and found significant variation in the reporting of these test specifications across studies. On average, studies reported 5 of the 17 items that would be required to specify the test conditions completely. A more complete and standardized reporting of methods, perhaps by means of a checklist, would improve the interpretation of FNAC DTA studies.

  3. Dynamics of Complexity and Accuracy: A Longitudinal Case Study of Advanced Untutored Development

    ERIC Educational Resources Information Center

    Polat, Brittany; Kim, Youjin

    2014-01-01

    This longitudinal case study follows a dynamic systems approach to investigate an under-studied research area in second language acquisition, the development of complexity and accuracy for an advanced untutored learner of English. Using the analytical tools of dynamic systems theory (Verspoor et al. 2011) within the framework of complexity,…

  4. Test Expectancy Affects Metacomprehension Accuracy

    ERIC Educational Resources Information Center

    Thiede, Keith W.; Wiley, Jennifer; Griffin, Thomas D.

    2011-01-01

    Background: Theory suggests that the accuracy of metacognitive monitoring is affected by the cues used to judge learning. Researchers have improved monitoring accuracy by directing attention to more appropriate cues; however, this is the first study to more directly point students to more appropriate cues using instructions regarding tests and…

  5. Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies: The PRISMA-DTA Statement.

    PubMed

    McInnes, Matthew D F; Moher, David; Thombs, Brett D; McGrath, Trevor A; Bossuyt, Patrick M; Clifford, Tammy; Cohen, Jérémie F; Deeks, Jonathan J; Gatsonis, Constantine; Hooft, Lotty; Hunt, Harriet A; Hyde, Christopher J; Korevaar, Daniël A; Leeflang, Mariska M G; Macaskill, Petra; Reitsma, Johannes B; Rodin, Rachel; Rutjes, Anne W S; Salameh, Jean-Paul; Stevens, Adrienne; Takwoingi, Yemisi; Tonelli, Marcello; Weeks, Laura; Whiting, Penny; Willis, Brian H

    2018-01-23

    Systematic reviews of diagnostic test accuracy synthesize data from primary diagnostic studies that have evaluated the accuracy of 1 or more index tests against a reference standard, provide estimates of test performance, allow comparisons of the accuracy of different tests, and facilitate the identification of sources of variability in test accuracy. To develop the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) diagnostic test accuracy guideline as a stand-alone extension of the PRISMA statement. Modifications to the PRISMA statement reflect the specific requirements for reporting of systematic reviews and meta-analyses of diagnostic test accuracy studies and the abstracts for these reviews. Established standards from the Enhancing the Quality and Transparency of Health Research (EQUATOR) Network were followed for the development of the guideline. The original PRISMA statement was used as a framework on which to modify and add items. A group of 24 multidisciplinary experts used a systematic review of articles on existing reporting guidelines and methods, a 3-round Delphi process, a consensus meeting, pilot testing, and iterative refinement to develop the PRISMA diagnostic test accuracy guideline. The final version of the PRISMA diagnostic test accuracy guideline checklist was approved by the group. The systematic review (produced 64 items) and the Delphi process (provided feedback on 7 proposed items; 1 item was later split into 2 items) identified 71 potentially relevant items for consideration. The Delphi process reduced these to 60 items that were discussed at the consensus meeting. Following the meeting, pilot testing and iterative feedback were used to generate the 27-item PRISMA diagnostic test accuracy checklist. To reflect specific or optimal contemporary systematic review methods for diagnostic test accuracy, 8 of the 27 original PRISMA items were left unchanged, 17 were modified, 2 were added, and 2 were omitted. The 27-item

  6. Results of a remote multiplexer/digitizer unit accuracy and environmental study

    NASA Technical Reports Server (NTRS)

    Wilner, D. O.

    1977-01-01

    A remote multiplexer/digitizer unit (RMDU), a part of the airborne integrated flight test data system, was subjected to an accuracy study. The study was designed to show the effects of temperature, altitude, and vibration on the RMDU. The RMDU was subjected to tests at temperatures from -54 C (-65 F) to 71 C (160 F), and the resulting data are presented here, along with a complete analysis of the effects. The methods and means used for obtaining correctable data and correcting the data are also discussed.

  7. Pedicle Screw Insertion Accuracy Using O-Arm, Robotic Guidance, or Freehand Technique: A Comparative Study.

    PubMed

    Laudato, Pietro Aniello; Pierzchala, Katarzyna; Schizas, Constantin

    2018-03-15

    A retrospective radiological study. The aim of this study was to evaluate the accuracy of pedicle screw insertion using O-Arm navigation, robotic assistance, or a freehand fluoroscopic technique. Pedicle screw insertion using either "O-Arm" navigation or robotic devices is gaining popularity. Although several studies are available evaluating each of those techniques separately, no direct comparison has been attempted. Eighty-four patients undergoing implantation of 569 lumbar and thoracic screws were divided into three groups. Eleven patients (64 screws) had screws inserted using robotic assistance, 25 patients (191 screws) using the O-arm, while 48 patients (314 screws) had screws inserted using lateral fluoroscopy in a freehand technique. A single experienced spine surgeon assisted by a spinal fellow performed all procedures. Screw placement accuracy was assessed by two independent observers on postoperative computed tomography (CTs) according to the A to D Rampersaud criteria. No statistically significant difference was noted between the three groups. About 70.4% of screws in the freehand group, 69.6% in the O arm group, and 78.8% in the robotic group were placed completely within the pedicle margins (grade A) (P > 0.05). About 6.4% of screws were considered misplaced (grades C&D) in the freehand group, 4.2% in the O-arm group, and 4.7% in the robotic group (P > 0.05). The spinal fellow inserted screws with the same accuracy as the senior surgeon (P > 0.05). The advent of new technologies does not appear to alter accuracy of screw placement in our setting. Under supervision, spinal fellows might perform equally well to experienced surgeons using new tools. The lack of difference in accuracy does not imply that the above-mentioned techniques have no added advantages. Other issues, such as surgeon/patient radiation, fiddle factor, teaching suitability, etc., outside the scope of our present study, need further assessment. 3.

  8. Accuracy Study of a 2-Component Point Doppler Velocimeter (PDV)

    NASA Technical Reports Server (NTRS)

    Kuhlman, John; Naylor, Steve; James, Kelly; Ramanath, Senthil

    1997-01-01

    A two-component Point Doppler Velocimeter (PDV) which has recently been developed is described, and a series of velocity measurements which have been obtained to quantify the accuracy of the PDV system are summarized. This PDV system uses molecular iodine vapor cells as frequency discriminating filters to determine the Doppler shift of laser light which is scattered off of seed particles in a flow. The majority of results which have been obtained to date are for the mean velocity of a rotating wheel, although preliminary data are described for fully-developed turbulent pipe flow. Accuracy of the present wheel velocity data is approximately +/- 1 % of full scale, while linearity of a single channel is on the order of +/- 0.5 % (i.e., +/- 0.6 m/sec and +/- 0.3 m/sec, out of 57 m/sec, respectively). The observed linearity of these results is on the order of the accuracy to which the speed of the rotating wheel has been set for individual data readings. The absolute accuracy of the rotating wheel data is shown to be consistent with the level of repeatability of the cell calibrations. The preliminary turbulent pipe flow data show consistent turbulence intensity values, and mean axial velocity profiles generally agree with pitot probe data. However, there is at present an offset error in the radial velocity which is on the order of 5-10 % of the mean axial velocity.

  9. Colour Doppler analysis of ophthalmic vessels in the diagnosis of carotic artery and retinal vein occlusion, diabetic retinopathy and glaucoma: systematic review of test accuracy studies.

    PubMed

    Bittner, Mario; Faes, Livia; Boehni, Sophie C; Bachmann, Lucas M; Schlingemann, Reinier O; Schmid, Martin K

    2016-12-07

    Colour Doppler analysis of ophthalmic vessels has been proposed as a promising tool in the diagnosis of various eye diseases, but the available diagnostic evidence has not yet been assessed systematically. We performed a comprehensive systematic review of the literature on the diagnostic properties of Colour Doppler imaging (CDI) assessing ophthalmic vessels and provide an inventory of the available evidence. Eligible papers were searched electronically in (Pre) Medline, Embase and Scopus, and via cross-checking of reference lists. The minimum requirement to be included was the availability of original data and the possibility to construct a two-by-two table. Study selection, critical appraisal using the QUADAS II instrument and extraction of salient study characteristics was made in duplicate. Sensitivity and specificity was computed for each study. We included 11 studies (15 two-by-two tables) of moderate methodological quality enrolling 820 participants (range 30 to 118). In 44.4% participants were female (range 37-59% in specific subgroups). CDI was assessed for internal carotid stenosis, diabetic retinopathy, glaucoma, and branch or central retinal vein occlusion diagnosis. There was insufficient data to pool the results for specific illnesses. For the assessments of ophthalmic arteries, mean sensitivity was 0.69 (range 0.27-0.96) with a corresponding mean specificity of 0.83 (range 0.70-0.96). Mean sensitivity of the central retinal artery assessments was 0.58 (range 0.31-0.84) and the corresponding mean specificity was 0.82 (range 0.63-0.94). Robust assessments of the diagnostic value of colour Doppler analysis remain uncommon, limiting the possibilities to extrapolate its true potential for clinical practice. PROSPERO 2014:CRD42014014027.

  10. Voice Identification: Levels-of-Processing and the Relationship between Prior Description Accuracy and Recognition Accuracy.

    ERIC Educational Resources Information Center

    Walter, Todd J.

    A study examined whether a person's ability to accurately identify a voice is influenced by factors similar to those proposed by the Supreme Court for eyewitness identification accuracy. In particular, the Supreme Court has suggested that a person's prior description accuracy of a suspect, degree of attention to a suspect, and confidence in…

  11. Accuracy of two geocoding methods for geographic information system-based exposure assessment in epidemiological studies.

    PubMed

    Faure, Elodie; Danjou, Aurélie M N; Clavel-Chapelon, Françoise; Boutron-Ruault, Marie-Christine; Dossus, Laure; Fervers, Béatrice

    2017-02-24

    Environmental exposure assessment based on Geographic Information Systems (GIS) and study participants' residential proximity to environmental exposure sources relies on the positional accuracy of subjects' residences to avoid misclassification bias. Our study compared the positional accuracy of two automatic geocoding methods to a manual reference method. We geocoded 4,247 address records representing the residential history (1990-2008) of 1,685 women from the French national E3N cohort living in the Rhône-Alpes region. We compared two automatic geocoding methods, a free-online geocoding service (method A) and an in-house geocoder (method B), to a reference layer created by manually relocating addresses from method A (method R). For each automatic geocoding method, positional accuracy levels were compared according to the urban/rural status of addresses and time-periods (1990-2000, 2001-2008), using Chi Square tests. Kappa statistics were performed to assess agreement of positional accuracy of both methods A and B with the reference method, overall, by time-periods and by urban/rural status of addresses. Respectively 81.4% and 84.4% of addresses were geocoded to the exact address (65.1% and 61.4%) or to the street segment (16.3% and 23.0%) with methods A and B. In the reference layer, geocoding accuracy was higher in urban areas compared to rural areas (74.4% vs. 10.5% addresses geocoded to the address or interpolated address level, p < 0.0001); no difference was observed according to the period of residence. Compared to the reference method, median positional errors were 0.0 m (IQR = 0.0-37.2 m) and 26.5 m (8.0-134.8 m), with positional errors <100 m for 82.5% and 71.3% of addresses, for method A and method B respectively. Positional agreement of method A and method B with method R was 'substantial' for both methods, with kappa coefficients of 0.60 and 0.61 for methods A and B, respectively. Our study demonstrates the feasibility of geocoding

  12. Accuracy of Carbohydrate Counting in Adults

    PubMed Central

    Rushton, Wanda E.

    2016-01-01

    In Brief This study investigates carbohydrate counting accuracy in patients using insulin through a multiple daily injection regimen or continuous subcutaneous insulin infusion. The average accuracy test score for all patients was 59%. The carbohydrate test in this study can be used to emphasize the importance of carbohydrate counting to patients and to provide ongoing education. PMID:27621531

  13. How to address patients' defences: a pilot study of the accuracy of defence interpretations and alliance.

    PubMed

    Junod, Olivier; de Roten, Yves; Martinez, Elena; Drapeau, Martin; Despland, Jean-Nicolas

    2005-12-01

    This pilot study examined the accuracy of therapist defence interpretations (TAD) in high-alliance patients (N = 7) and low-alliance patients (N = 8). TAD accuracy was assessed in the two subgroups by comparing for each case the patient's most frequent defensive level with the most frequent defensive level addressed by the therapist when making defence interpretations. Results show that in high-alliance patient-therapist dyads, the therapists tend to address accurate or higher (more mature) defensive level than patients most frequent level. On the other hand, the therapists address lower (more immature) defensive level in low-alliance dyads. These results are discussed along with possible ways to better assess TAD accuracy.

  14. A systematic review of the sensitivity and specificity of the toe-brachial index for detecting peripheral artery disease.

    PubMed

    Tehan, Peta Ellen; Santos, Derek; Chuter, Vivienne Helaine

    2016-08-01

    The toe-brachial index (TBI) is used as an adjunct to the ankle-brachial index (ABI) for non-invasive lower limb vascular screening. With increasing evidence suggesting limitations of the ABI for diagnosis of vascular complications, particularly in specific populations including diabetes cohorts, the TBI is being used more widely. The aim of this review was to determine the sensitivity and specificity of the TBI for detecting peripheral artery disease (PAD) in populations at risk of this disease. A database search was conducted to identify current work relating to the sensitivity and specificity of toe-brachial indices up to July 2015. Only studies using valid diagnostic imaging as a reference standard were included. The QUADAS-2 tool was used to critically appraise included articles. Seven studies met the inclusion criteria. Sensitivity of the TBI for PAD was reported in all seven studies and ranged from 45% to 100%; specificity was reported by five studies only and ranged from 16% to 100%. In conclusion, this review suggests that the TBI has variable diagnostic accuracy for the presence of PAD in specific populations at risk of developing the disease. There was a notable lack of large-scale diagnostic accuracy studies determining the diagnostic accuracy of the TBI in detecting PAD in different at-risk cohorts. However, standardised normal values need to be established for the TBI to conclusively determine the diagnostic accuracy of this test. © The Author(s) 2016.

  15. Accuracy of Continuous Glucose Monitoring During Three Closed-Loop Home Studies Under Free-Living Conditions.

    PubMed

    Thabit, Hood; Leelarathna, Lalantha; Wilinska, Malgorzata E; Elleri, Daniella; Allen, Janet M; Lubina-Solomon, Alexandra; Walkinshaw, Emma; Stadler, Marietta; Choudhary, Pratik; Mader, Julia K; Dellweg, Sibylle; Benesch, Carsten; Pieber, Thomas R; Arnolds, Sabine; Heller, Simon R; Amiel, Stephanie A; Dunger, David; Evans, Mark L; Hovorka, Roman

    2015-11-01

    Closed-loop (CL) systems modulate insulin delivery based on glucose levels measured by a continuous glucose monitor (CGM). Accuracy of the CGM affects CL performance and safety. We evaluated the accuracy of the Freestyle Navigator(®) II CGM (Abbott Diabetes Care, Alameda, CA) during three unsupervised, randomized, open-label, crossover home CL studies. Paired CGM and capillary glucose values (10,597 pairs) were collected from 57 participants with type 1 diabetes (41 adults [mean±SD age, 39±12 years; mean±SD hemoglobin A1c, 7.9±0.8%] recruited at five centers and 16 adolescents [mean±SD age, 15.6±3.6 years; mean±SD hemoglobin A1c, 8.1±0.8%] recruited at two centers). Numerical accuracy was assessed by absolute relative difference (ARD) and International Organization for Standardization (ISO) 15197:2013 15/15% limits, and clinical accuracy was assessed by Clarke error grid analysis. Total duration of sensor use was 2,002 days (48,052 h). Overall sensor accuracy for the capillary glucose range (1.1-27.8 mmol/L) showed mean±SD and median (interquartile range) ARD of 14.2±15.5% and 10.0% (4.5%, 18.4%), respectively. Lowest mean ARD was observed in the hyperglycemic range (9.8±8.8%). Over 95% of pairs were in combined Clarke error grid Zones A and B (A, 80.1%, B, 16.2%). Overall, 70.0% of the sensor readings satisfied ISO criteria. Mean ARD was consistent (12.3%; 95% of the values fall within ±3.7%) and not different between participants (P=0.06) within the euglycemic and hyperglycemic range, when CL is actively modulating insulin delivery. Consistent accuracy of the CGM within the euglycemic-hyperglycemic range using the Freestyle Navigator II was observed and supports its use in home CL studies. Our results may contribute toward establishing normative CGM performance criteria for unsupervised home use of CL.

  16. Evaluation of Automatic Vehicle Location accuracy

    DOT National Transportation Integrated Search

    1999-01-01

    This study assesses the accuracy of the Automatic Vehicle Location (AVL) data provided for the buses of the Ann Arbor Transportation Authority with Global Positioning System (GPS) technology. In a sample of eighty-nine bus trips two kinds of accuracy...

  17. Trade-off study and computer simulation for assessing spacecraft pointing accuracy and stability capabilities

    NASA Astrophysics Data System (ADS)

    Algrain, Marcelo C.; Powers, Richard M.

    1997-05-01

    A case study, written in a tutorial manner, is presented where a comprehensive computer simulation is developed to determine the driving factors contributing to spacecraft pointing accuracy and stability. Models for major system components are described. Among them are spacecraft bus, attitude controller, reaction wheel assembly, star-tracker unit, inertial reference unit, and gyro drift estimators (Kalman filter). The predicted spacecraft performance is analyzed for a variety of input commands and system disturbances. The primary deterministic inputs are the desired attitude angles and rate set points. The stochastic inputs include random torque disturbances acting on the spacecraft, random gyro bias noise, gyro random walk, and star-tracker noise. These inputs are varied over a wide range to determine their effects on pointing accuracy and stability. The results are presented in the form of trade- off curves designed to facilitate the proper selection of subsystems so that overall spacecraft pointing accuracy and stability requirements are met.

  18. A systematic review of methods to diagnose oral dryness and salivary gland function

    PubMed Central

    2012-01-01

    Background The most advocated clinical method for diagnosing salivary dysfunction is to quantitate unstimulated and stimulated whole saliva (sialometry). Since there is an expected and wide variation in salivary flow rates among individuals, the assessment of dysfunction can be difficult. The aim of this systematic review is to evaluate the quality of the evidence for the efficacy of diagnostic methods used to identify oral dryness. Methods A literature search, with specific indexing terms and a hand search, was conducted for publications that described a method to diagnose oral dryness. The electronic databases of PubMed, Cochrane Library, and Web of Science were used as data sources. Four reviewers selected publications on the basis of predetermined inclusion and exclusion criteria. Data were extracted from the selected publications using a protocol. Original studies were interpreted with the aid of Quality Assessment of Diagnostic Accuracy Studies (QUADAS) tool. Results The database searches resulted in 224 titles and abstracts. Of these abstracts, 80 publications were judged to meet the inclusion criteria and read in full. A total of 18 original studies were judged relevant and interpreted for this review. In all studies, the results of the test method were compared to those of a reference method. Based on the interpretation (with the aid of the QUADAS tool) it can be reported that the patient selection criteria were not clearly described and the test or reference methods were not described in sufficient detail for it to be reproduced. None of the included studies reported information on uninterpretable/intermediate results nor data on observer or instrument variation. Seven of the studies presented their results as a percentage of correct diagnoses. Conclusions The evidence for the efficacy of clinical methods to assess oral dryness is sparse and it can be stated that improved standards for the reporting of diagnostic accuracy are needed in order to assure the

  19. Accuracy of transvaginal ultrasound for diagnosis of deep endometriosis in uterosacral ligaments, rectovaginal septum, vagina and bladder: systematic review and meta-analysis.

    PubMed

    Guerriero, S; Ajossa, S; Minguez, J A; Jurado, M; Mais, V; Melis, G B; Alcazar, J L

    2015-11-01

    To review the diagnostic accuracy of transvaginal ultrasound (TVS) in the preoperative detection of endometriosis in the uterosacral ligaments (USL), rectovaginal septum (RVS), vagina and bladder in patients with clinical suspicion of deep infiltrating endometriosis (DIE). An extensive search was performed in MEDLINE (PubMed) and EMBASE for studies published between January 1989 and December 2014. Studies were considered eligible if they reported on the use of TVS for the preoperative detection of endometriosis in the USL, RVS, vagina and bladder in women with clinical suspicion of DIE using the surgical data as a reference standard. Study quality was assessed using the PRISMA guidelines and QUADAS-2 tool. Of the 801 citations identified, 11 studies (n = 1583) were considered eligible and were included in the meta-analysis. For detection of endometriosis in the USL, the overall pooled sensitivity and specificity of TVS were 53% (95%CI, 35-70%) and 93% (95%CI, 83-97%), respectively. The pretest probability of USL endometriosis was 54%, which increased to 90% when suspicion of endometriosis was present after TVS examination. For detection of endometriosis in the RVS, the overall pooled sensitivity and specificity were 49% (95%CI, 36-62%) and 98% (95%CI, 95-99%), respectively. The pretest probability of RVS endometriosis was 24%, which increased to 89% when suspicion of endometriosis was present after TVS examination. For detection of vaginal endometriosis, the overall pooled sensitivity and specificity were 58% (95%CI, 40-74%) and 96% (95%CI, 87-99%), respectively. The pretest probability of vaginal endometriosis was 17%, which increased to 76% when suspicion of endometriosis was present after TVS assessment. Substantial heterogeneity was found for sensitivity and specificity for all these locations. For detection of bladder endometriosis, the overall pooled sensitivity and specificity were 62% (95%CI, 40-80%) and 100% (95%CI, 97-100%), respectively. Moderate

  20. Accuracy Study of a Robotic System for MRI-guided Prostate Needle Placement

    PubMed Central

    Seifabadi, Reza; Cho, Nathan BJ.; Song, Sang-Eun; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M.; Fichtinger, Gabor; Iordachita, Iulian

    2013-01-01

    Background Accurate needle placement is the first concern in percutaneous MRI-guided prostate interventions. In this phantom study, different sources contributing to the overall needle placement error of a MRI-guided robot for prostate biopsy have been identified, quantified, and minimized to the possible extent. Methods and Materials The overall needle placement error of the system was evaluated in a prostate phantom. This error was broken into two parts: the error associated with the robotic system (called before-insertion error) and the error associated with needle-tissue interaction (called due-to-insertion error). The before-insertion error was measured directly in a soft phantom and different sources contributing into this part were identified and quantified. A calibration methodology was developed to minimize the 4-DOF manipulator’s error. The due-to-insertion error was indirectly approximated by comparing the overall error and the before-insertion error. The effect of sterilization on the manipulator’s accuracy and repeatability was also studied. Results The average overall system error in phantom study was 2.5 mm (STD=1.1mm). The average robotic system error in super soft phantom was 1.3 mm (STD=0.7 mm). Assuming orthogonal error components, the needle-tissue interaction error was approximated to be 2.13 mm thus having larger contribution to the overall error. The average susceptibility artifact shift was 0.2 mm. The manipulator’s targeting accuracy was 0.71 mm (STD=0.21mm) after robot calibration. The robot’s repeatability was 0.13 mm. Sterilization had no noticeable influence on the robot’s accuracy and repeatability. Conclusions The experimental methodology presented in this paper may help researchers to identify, quantify, and minimize different sources contributing into the overall needle placement error of an MRI-guided robotic system for prostate needle placement. In the robotic system analyzed here, the overall error of the studied system

  1. Accuracy study of a robotic system for MRI-guided prostate needle placement.

    PubMed

    Seifabadi, Reza; Cho, Nathan B J; Song, Sang-Eun; Tokuda, Junichi; Hata, Nobuhiko; Tempany, Clare M; Fichtinger, Gabor; Iordachita, Iulian

    2013-09-01

    Accurate needle placement is the first concern in percutaneous MRI-guided prostate interventions. In this phantom study, different sources contributing to the overall needle placement error of a MRI-guided robot for prostate biopsy have been identified, quantified and minimized to the possible extent. The overall needle placement error of the system was evaluated in a prostate phantom. This error was broken into two parts: the error associated with the robotic system (called 'before-insertion error') and the error associated with needle-tissue interaction (called 'due-to-insertion error'). Before-insertion error was measured directly in a soft phantom and different sources contributing into this part were identified and quantified. A calibration methodology was developed to minimize the 4-DOF manipulator's error. The due-to-insertion error was indirectly approximated by comparing the overall error and the before-insertion error. The effect of sterilization on the manipulator's accuracy and repeatability was also studied. The average overall system error in the phantom study was 2.5 mm (STD = 1.1 mm). The average robotic system error in the Super Soft plastic phantom was 1.3 mm (STD = 0.7 mm). Assuming orthogonal error components, the needle-tissue interaction error was found to be approximately 2.13 mm, thus making a larger contribution to the overall error. The average susceptibility artifact shift was 0.2 mm. The manipulator's targeting accuracy was 0.71 mm (STD = 0.21 mm) after robot calibration. The robot's repeatability was 0.13 mm. Sterilization had no noticeable influence on the robot's accuracy and repeatability. The experimental methodology presented in this paper may help researchers to identify, quantify and minimize different sources contributing into the overall needle placement error of an MRI-guided robotic system for prostate needle placement. In the robotic system analysed here, the overall error of the studied system

  2. Accuracy Study of the Space-Time CE/SE Method for Computational Aeroacoustics Problems Involving Shock Waves

    NASA Technical Reports Server (NTRS)

    Wang, Xiao Yen; Chang, Sin-Chung; Jorgenson, Philip C. E.

    1999-01-01

    The space-time conservation element and solution element(CE/SE) method is used to study the sound-shock interaction problem. The order of accuracy of numerical schemes is investigated. The linear model problem.govemed by the 1-D scalar convection equation, sound-shock interaction problem governed by the 1-D Euler equations, and the 1-D shock-tube problem which involves moving shock waves and contact surfaces are solved to investigate the order of accuracy of numerical schemes. It is concluded that the accuracy of the CE/SE numerical scheme with designed 2nd-order accuracy becomes 1st order when a moving shock wave exists. However, the absolute error in the CE/SE solution downstream of the shock wave is on the same order as that obtained using a fourth-order accurate essentially nonoscillatory (ENO) scheme. No special techniques are used for either high-frequency low-amplitude waves or shock waves.

  3. Simulation approach for the evaluation of tracking accuracy in radiotherapy: a preliminary study.

    PubMed

    Tanaka, Rie; Ichikawa, Katsuhiro; Mori, Shinichiro; Sanada, Sigeru

    2013-01-01

    Real-time tumor tracking in external radiotherapy can be achieved by diagnostic (kV) X-ray imaging with a dynamic flat-panel detector (FPD). It is important to keep the patient dose as low as possible while maintaining tracking accuracy. A simulation approach would be helpful to optimize the imaging conditions. This study was performed to develop a computer simulation platform based on a noise property of the imaging system for the evaluation of tracking accuracy at any noise level. Flat-field images were obtained using a direct-type dynamic FPD, and noise power spectrum (NPS) analysis was performed. The relationship between incident quantum number and pixel value was addressed, and a conversion function was created. The pixel values were converted into a map of quantum number using the conversion function, and the map was then input into the random number generator to simulate image noise. Simulation images were provided at different noise levels by changing the incident quantum numbers. Subsequently, an implanted marker was tracked automatically and the maximum tracking errors were calculated at different noise levels. The results indicated that the maximum tracking error increased with decreasing incident quantum number in flat-field images with an implanted marker. In addition, the range of errors increased with decreasing incident quantum number. The present method could be used to determine the relationship between image noise and tracking accuracy. The results indicated that the simulation approach would aid in determining exposure dose conditions according to the necessary tracking accuracy.

  4. Alpha-defensin and the Synovasure lateral flow device for the diagnosis of prosthetic joint infection.

    PubMed

    Marson, B A; Deshmukh, S R; Grindlay, D J C; Scammell, B E

    2018-06-01

    Aims The aim of this review was to evaluate the available literature and to calculate the pooled sensitivity and specificity for the different alpha-defensin test systems that may be used to diagnose prosthetic joint infection (PJI). Materials and Methods Studies using alpha-defensin or Synovasure (Zimmer Biomet, Warsaw, Indiana) to diagnose PJI were identified from systematic searches of electronic databases. The quality of the studies was evaluated using the Quality Assessment of Studies of Diagnostic Accuracy (QUADAS) tool. Meta-analysis was completed using a bivariate model. Results A total of 11 eligible studies were included. The median QUADAS score was 13 (interquartile range 13 to 13) out of 14. Significant conflicts of interest were identified in five studies. The pooled sensitivity for the laboratory alpha-defensin test was 0.95 (95% confidence interval (CI) 0.91 to 0.98) and the pooled specificity was 0.97 (95% CI 0.95 to 0.98) for four studies with a threshold level of 5.2 mgl -1 The pooled sensitivity for the lateral flow cassette test was 0.85 (95% CI 0.74 to 0.92) and the pooled specificity was 0.90 (95% CI 0.91 to 0.98). There was a statistically significant difference in sensitivity (p = 0.019), but not specificity (p = 0.47). Conclusion Laboratory-based alpha-defensin testing remains a promising tool for diagnosing PJI. The lateral flow cassette has a significantly lower performance and pooled results are comparable to the leucocyte esterase test. Further studies are required before the widespread adoption of the lateral flow cassette alpha-defensin test. Cite this article: Bone Joint J 2018;100-B:703-11.

  5. Is Diagnostic Performance of Quantitative 2D-Shear Wave Elastography Optimal for Clinical Classification of Benign and Malignant Thyroid Nodules?: A Systematic Review and Meta-analysis.

    PubMed

    Nattabi, Haliimah A; Sharif, Norhafidzah M; Yahya, Noorazrul; Ahmad, Rozilawati; Mohamad, Mazlyfarina; Zaki, Faizah M; Yusoff, Ahmad N

    2017-10-17

    This study is a dedicated 2D-shear wave elastography (2D-SWE) review aimed at systematically eliciting up-to-date evidence of its clinical value in differential diagnosis of benign and malignant thyroid nodules. PubMed, Web of Science, and Scopus databases were searched for studies assessing the diagnostic value of 2D-SWE for thyroid malignancy risk stratification published until December 2016. The retrieved titles and abstracts were screened and evaluated according to the predefined inclusion and exclusion criteria. Methodological quality of the studies was assessed using the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Review 2 (QUADAS-2) tool. Extracted 2D-SWE diagnostic performance data were meta-analyzed to assess the summary sensitivity, specificity, and area under the receiver operating characteristic curve. After stepwise review, 14 studies in which 2D-SWE was used to evaluate 2851 thyroid nodules (1092 malignant, 1759 benign) from 2139 patients were selected for the current study. Study quality on QUADAS-2 assessment was moderate to high. The summary sensitivity, specificity and area under the receiver operating characteristic curve of 2D-SWE for differential diagnosis of benign and malignant thyroid nodules were 0.66 (95% confidence interval [CI]: 0.64-0.69), 0.78 (CI: 0.76-0.80), and 0.851 (Q* = 0.85), respectively. The pooled diagnostic odds ratio, negative likelihood ratio, and positive likelihood ratio were 12.73 (CI: 8.80-18.43), 0.31 (CI: 0.22-0.44), and 3.87 (CI: 2.83-5.29), respectively. Diagnostic performance of quantitative 2D-SWE for malignancy risk stratification of thyroid nodules is suboptimal with mediocre sensitivity and specificity, contrary to earlier reports of excellence. Copyright © 2017 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.

  6. A bibliometric analysis of evaluative medical education studies: characteristics and indexing accuracy.

    PubMed

    Sampson, Margaret; Horsley, Tanya; Doja, Asif

    2013-03-01

    To determine the characteristics of medical education studies published in general and internal medicine (GIM) and medical education journals, and to analyze the accuracy of their indexing. The authors identified the five GIM and five medical education journals that published the most articles indexed in MEDLINE as medical education during January 2001 to January 2010. They searched Ovid MEDLINE for evaluative medical education studies published in these journals during this period and classified them as quantitative or qualitative studies according to MEDLINE indexing. They also examined themes and learner levels targeted. Using a random sample of records, they assessed the accuracy of study-type indexing. Of 4,418 records retrieved, 3,853 (87.2%) were from medical education journals and 565 (12.3%) were from GIM journals. Qualitative studies and program evaluations were more prevalent within medical education journals, whereas GIM journals published a higher proportion of clinical trials and systematic reviews (χ=74.28, df=3, P<.001). Medical education journals had a concentration of studies targeting medical students, whereas GIM journals had a concentration targeting residents; themes were similar. The authors confirmed that 170 (56.7%) of the 300 sampled articles were correctly classified in MEDLINE as evaluative studies. The majority of the identified evaluative studies were published in medical education journals, confirming the integrity of medical education as a specialty. Findings concerning the study types published in medical education versus GIM journals are important for medical education researchers who seek to publish outside the field's specialty journals.

  7. EM-navigated catheter placement for gynecologic brachytherapy: an accuracy study

    NASA Astrophysics Data System (ADS)

    Mehrtash, Alireza; Damato, Antonio; Pernelle, Guillaume; Barber, Lauren; Farhat, Nabgha; Viswanathan, Akila; Cormack, Robert; Kapur, Tina

    2014-03-01

    Gynecologic malignancies, including cervical, endometrial, ovarian, vaginal and vulvar cancers, cause significant mortality in women worldwide. The standard care for many primary and recurrent gynecologic cancers consists of chemoradiation followed by brachytherapy. In high dose rate (HDR) brachytherapy, intracavitary applicators and /or interstitial needles are placed directly inside the cancerous tissue so as to provide catheters to deliver high doses of radiation. Although technology for the navigation of catheters and needles is well developed for procedures such as prostate biopsy, brain biopsy, and cardiac ablation, it is notably lacking for gynecologic HDR brachytherapy. Using a benchtop study that closely mimics the clinical interstitial gynecologic brachytherapy procedure, we developed a method for evaluating the accuracy of image-guided catheter placement. Future bedside translation of this technology offers the potential benefit of maximizing tumor coverage during catheter placement while avoiding damage to the adjacent organs, for example bladder, rectum and bowel. In the study, two independent experiments were performed on a phantom model to evaluate the targeting accuracy of an electromagnetic (EM) tracking system. The procedure was carried out using a laptop computer (2.1GHz Intel Core i7 computer, 8GB RAM, Windows 7 64-bit), an EM Aurora tracking system with a 1.3mm diameter 6 DOF sensor, and 6F (2 mm) brachytherapy catheters inserted through a Syed-Neblett applicator. The 3D Slicer and PLUS open source software were used to develop the system. The mean of the targeting error was less than 2.9mm, which is comparable to the targeting errors in commercial clinical navigation systems.

  8. The accuracy of colonoscopic localisation of colorectal tumours: a prospective, multi-centred observational study.

    PubMed

    Johnstone, M S; Moug, S J

    2014-05-01

    Colonoscopy is essential for accurate pre-operative colorectal tumour localisation, but its accuracy for localisation remains undetermined due to limitations of previous work. This study aimed to establish the accuracy of colonoscopic localisation and to determine how frequently inaccuracy results in altered surgical management. A prospective, multi-centred, powered observational study recruited 79 patients with colorectal tumours that underwent curative surgical resection. Patient and colonoscopic factors were recorded. Pre-operative colonoscopic and radiological lesion localisations were compared to intra-operative localisation using pre-defined anatomical bowel segments to determine accuracy, with changes in planned surgical management documented. Colonoscopy accurately located the colorectal tumour in 64/79 patients (81%). Five out of 15 inaccurately located patients required on-table alteration in planned surgical management. Pre-operative imaging was unable to visualise the primary tumour in 23.1% of cases, a finding that was more prevalent amongst bowel screener patients compared to symptomatic patients (45.8% vs. 13%; p = 0.003). Colonoscopic lesion localisation is inaccurate in 19.0% of cases and occurred throughout the colon with a change in on-table surgical management in 6.3%. With CT unable to visualise lesions in just under a quarter of cases, particularly in the screening population, preoperative localisation is heavily reliant on colonoscopy.

  9. On the accuracy of personality judgment: a realistic approach.

    PubMed

    Funder, D C

    1995-10-01

    The "accuracy paradigm" for the study of personality judgment provides an important, new complement to the "error paradigm" that dominated this area of research for almost 2 decades. The present article introduces a specific approach within the accuracy paradigm called the Realistic Accuracy Model (RAM). RAM begins with the assumption that personality traits are real attributes of individuals. This assumption entails the use of a broad array of criteria for the evaluation of personality judgment and leads to a model that describes accuracy as a function of the availability, detection, and utilization of relevant behavioral cues. RAM provides a common explanation for basic moderators of accuracy, sheds light on how these moderators interact, and outlines a research agenda that includes the reintegration of the study of error with the study of accuracy.

  10. Diagnostic accuracy of endoscopic ultrasonography (EUS) for the preoperative locoregional staging of primary gastric cancer.

    PubMed

    Mocellin, Simone; Pasquali, Sandro

    2015-02-06

    form. We assessed data quality using a standard procedure according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) criteria. We performed diagnostic accuracy meta-analysis using the hierarchical bivariate method. We identified 66 articles (published between 1988 and 2012) that were eligible according to the inclusion criteria. We collected the data on 7747 patients with gastric cancer who were staged with EUS. Overall the quality of the included studies was good: in particular, only five studies presented a high risk of index test interpretation bias and two studies presented a high risk of selection bias.For primary tumor (T) stage, results were stratified according to the depth of invasion of the gastric wall. The meta-analysis of 50 studies (n = 4397) showed that the summary sensitivity and specificity of EUS in discriminating T1 to T2 (superficial) versus T3 to T4 (advanced) gastric carcinomas were 0.86 (95% confidence interval (CI) 0.81 to 0.90) and 0.90 (95% CI 0.87 to 0.93) respectively. For the diagnostic capacity of EUS to distinguish T1 (early gastric cancer, EGC) versus T2 (muscle-infiltrating) tumors, the meta-analysis of 46 studies (n = 2742) showed that the summary sensitivity and specificity were 0.85 (95% CI 0.78 to 0.91) and 0.90 (95% CI 0.85 to 0.93) respectively. When we addressed the capacity of EUS to distinguish between T1a (mucosal) versus T1b (submucosal) cancers the meta-analysis of 20 studies (n = 3321) showed that the summary sensitivity and specificity were 0.87 (95% CI 0.81 to 0.92) and 0.75 (95% CI 0.62 to 0.84) respectively. Finally, for the metastatic involvement of lymph nodes (N-stage), the meta-analysis of 44 studies (n = 3573) showed that the summary sensitivity and specificity were 0.83 (95% CI 0.79 to 0.87) and 0.67 (95% CI 0.61 to 0.72), respectively.Overall, as demonstrated also by the Bayesian nomograms, which enable readers to calculate post-test probabilities for any target condition prevalence, the EUS

  11. Accuracy Evaluation of 19 Blood Glucose Monitoring Systems Manufactured in the Asia-Pacific Region: A Multicenter Study.

    PubMed

    Yu-Fei, Wang; Wei-Ping, Jia; Ming-Hsun, Wu; Miao-O, Chien; Ming-Chang, Hsieh; Chi-Pin, Wang; Ming-Shih, Lee

    2017-09-01

    System accuracy of current blood glucose monitors (BGMs) in the market has already been evaluated extensively, yet mostly focused on European and North American manufacturers. Data on BGMs manufactured in the Asia-Pacific region remain to be established. In this study, we sought to assess the accuracy performance of 19 BGMs manufactured in the Asia-pacific region. A total of 19 BGMs were obtained from local pharmacies in China. The study was conducted at three hospitals located in the Asia-Pacific region. Measurement results of each system were compared with results of the reference instrument (YSI 2300 PLUS Glucose Analyzer), and accuracy evaluation was performed in accordance to the ISO 15197:2003 and updated 2015 guidelines. Radar plots, which is a new method, are described herein to visualize the analytical performance of the 19 BGMs evaluated. Consensus error grid is a tool for evaluating the clinical significance of the results. The 19 BGMs resulted in a satisfaction rate between 83.5% and 100.0% within ISO 15197:2003 error limits, and between 71.3% and 100.0% within EN ISO 15197:2015 (ISO 15197:2013) error limits. Of the 19 BGMs evaluated, 12 met the minimal accuracy requirement of the ISO 15197:2003 standard, whereas only 4 met the tighter EN ISO 15197:2015 (ISO 15197:2013) requirements. Accuracy evaluation of BGMs should be performed regularly to maximize patient safety.

  12. Performance characteristics of optical coherence tomography in assessment of Barrett's esophagus and esophageal cancer: systematic review.

    PubMed

    Kohli, D R; Schubert, M L; Zfass, A M; Shah, T U

    2017-11-01

    Optical coherence tomography (OCT) can generate high-resolution images of the esophagus that allows cross-sectional visualization of esophageal wall layers. We conducted a systematic review to assess the utility of OCT for diagnosing of esophageal intestinal metaplasia (IM; Barrett's esophagus BE)), dysplasia, cancer and staging of early esophageal cancer. English language human observational studies and clinical trials published in PubMed and Embase were included if they assessed any of the following: (i) in-vivo features and accuracy of OCT at diagnosing esophageal IM, sub-squamous intestinal metaplasia (SSIM), dysplasia, or cancer, and (ii) accuracy of OCT in staging esophageal cancer. Twenty-one of the 2,068 retrieved citations met inclusion criteria. In the two prospective studies that assessed accuracy of OCT at identifying IM, sensitivity was 81%-97%, and specificity was 57%-92%. In the two prospective studies that assessed accuracy of OCT at identifying dysplasia and early cancer, sensitivity was 68%-83%, and specificity was 75%-82%. Observational studies described significant variability in the ability of OCT to accurately identify SSIM. Two prospective studies that compared the accuracy of OCT at staging early squamous cell carcinoma to histologic resection specimens reported accuracy of >90%. Risk of bias and applicability concerns was rated as low among the prospective studies using the QUADAS-2 questionnaire. OCT may identify intestinal metaplasia and dysplasia, but its accuracy may not meet recommended thresholds to replace 4-quadrant biopsies in clinical practice. OCT may be more accurate than EUS at staging early esophageal cancer, but randomized trials and cost-effective analyses are lacking. © The Authors 2017. Published by Oxford University Press on behalf of International Society for Diseases of the Esophagus. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Do knowledge, knowledge sources and reasoning skills affect the accuracy of nursing diagnoses? a randomised study.

    PubMed

    Paans, Wolter; Sermeus, Walter; Nieweg, Roos Mb; Krijnen, Wim P; van der Schans, Cees P

    2012-08-01

    This paper reports a study about the effect of knowledge sources, such as handbooks, an assessment format and a predefined record structure for diagnostic documentation, as well as the influence of knowledge, disposition toward critical thinking and reasoning skills, on the accuracy of nursing diagnoses.Knowledge sources can support nurses in deriving diagnoses. A nurse's disposition toward critical thinking and reasoning skills is also thought to influence the accuracy of his or her nursing diagnoses. A randomised factorial design was used in 2008-2009 to determine the effect of knowledge sources. We used the following instruments to assess the influence of ready knowledge, disposition, and reasoning skills on the accuracy of diagnoses: (1) a knowledge inventory, (2) the California Critical Thinking Disposition Inventory, and (3) the Health Science Reasoning Test. Nurses (n = 249) were randomly assigned to one of four factorial groups, and were instructed to derive diagnoses based on an assessment interview with a simulated patient/actor. The use of a predefined record structure resulted in a significantly higher accuracy of nursing diagnoses. A regression analysis reveals that almost half of the variance in the accuracy of diagnoses is explained by the use of a predefined record structure, a nurse's age and the reasoning skills of `deduction' and `analysis'. Improving nurses' dispositions toward critical thinking and reasoning skills, and the use of a predefined record structure, improves accuracy of nursing diagnoses.

  14. Do knowledge, knowledge sources and reasoning skills affect the accuracy of nursing diagnoses? a randomised study

    PubMed Central

    2012-01-01

    Background This paper reports a study about the effect of knowledge sources, such as handbooks, an assessment format and a predefined record structure for diagnostic documentation, as well as the influence of knowledge, disposition toward critical thinking and reasoning skills, on the accuracy of nursing diagnoses. Knowledge sources can support nurses in deriving diagnoses. A nurse’s disposition toward critical thinking and reasoning skills is also thought to influence the accuracy of his or her nursing diagnoses. Method A randomised factorial design was used in 2008–2009 to determine the effect of knowledge sources. We used the following instruments to assess the influence of ready knowledge, disposition, and reasoning skills on the accuracy of diagnoses: (1) a knowledge inventory, (2) the California Critical Thinking Disposition Inventory, and (3) the Health Science Reasoning Test. Nurses (n = 249) were randomly assigned to one of four factorial groups, and were instructed to derive diagnoses based on an assessment interview with a simulated patient/actor. Results The use of a predefined record structure resulted in a significantly higher accuracy of nursing diagnoses. A regression analysis reveals that almost half of the variance in the accuracy of diagnoses is explained by the use of a predefined record structure, a nurse’s age and the reasoning skills of `deduction’ and `analysis’. Conclusions Improving nurses’ dispositions toward critical thinking and reasoning skills, and the use of a predefined record structure, improves accuracy of nursing diagnoses. PMID:22852577

  15. Sound source localization identification accuracy: Envelope dependencies.

    PubMed

    Yost, William A

    2017-07-01

    Sound source localization accuracy as measured in an identification procedure in a front azimuth sound field was studied for click trains, modulated noises, and a modulated tonal carrier. Sound source localization accuracy was determined as a function of the number of clicks in a 64 Hz click train and click rate for a 500 ms duration click train. The clicks were either broadband or high-pass filtered. Sound source localization accuracy was also measured for a single broadband filtered click and compared to a similar broadband filtered, short-duration noise. Sound source localization accuracy was determined as a function of sinusoidal amplitude modulation and the "transposed" process of modulation of filtered noises and a 4 kHz tone. Different rates (16 to 512 Hz) of modulation (including unmodulated conditions) were used. Providing modulation for filtered click stimuli, filtered noises, and the 4 kHz tone had, at most, a very small effect on sound source localization accuracy. These data suggest that amplitude modulation, while providing information about interaural time differences in headphone studies, does not have much influence on sound source localization accuracy in a sound field.

  16. L2 Speaking Development during Study Abroad: Fluency, Accuracy, Complexity, and Underlying Cognitive Factors

    ERIC Educational Resources Information Center

    Leonard, Karen Ruth; Shea, Christine E.

    2017-01-01

    We take a multidimensional perspective on the development of second language (L2) speaking ability and examine how changes in the underlying cognitive variables of linguistic knowledge and processing speed interact with complexity, fluency, and accuracy over the course of a 3-month Spanish study abroad session. Study abroad provides a unique…

  17. Social class, contextualism, and empathic accuracy.

    PubMed

    Kraus, Michael W; Côté, Stéphane; Keltner, Dacher

    2010-11-01

    Recent research suggests that lower-class individuals favor explanations of personal and political outcomes that are oriented to features of the external environment. We extended this work by testing the hypothesis that, as a result, individuals of a lower social class are more empathically accurate in judging the emotions of other people. In three studies, lower-class individuals (compared with upper-class individuals) received higher scores on a test of empathic accuracy (Study 1), judged the emotions of an interaction partner more accurately (Study 2), and made more accurate inferences about emotion from static images of muscle movements in the eyes (Study 3). Moreover, the association between social class and empathic accuracy was explained by the tendency for lower-class individuals to explain social events in terms of features of the external environment. The implications of class-based patterns in empathic accuracy for well-being and relationship outcomes are discussed.

  18. Feature instructions improve face-matching accuracy

    PubMed Central

    Bindemann, Markus

    2018-01-01

    Identity comparisons of photographs of unfamiliar faces are prone to error but important for applied settings, such as person identification at passport control. Finding techniques to improve face-matching accuracy is therefore an important contemporary research topic. This study investigated whether matching accuracy can be improved by instruction to attend to specific facial features. Experiment 1 showed that instruction to attend to the eyebrows enhanced matching accuracy for optimized same-day same-race face pairs but not for other-race faces. By contrast, accuracy was unaffected by instruction to attend to the eyes, and declined with instruction to attend to ears. Experiment 2 replicated the eyebrow-instruction improvement with a different set of same-race faces, comprising both optimized same-day and more challenging different-day face pairs. These findings suggest that instruction to attend to specific features can enhance face-matching accuracy, but feature selection is crucial and generalization across face sets may be limited. PMID:29543822

  19. In vivo Study of the Accuracy of Dual-arch Impressions.

    PubMed

    de Lima, Luciana Martinelli Santayana; Borges, Gilberto Antonio; Junior, Luiz Henrique Burnett; Spohr, Ana Maria

    2014-06-01

    This study evaluated in vivo the accuracy of metal (Smart®) and plastic (Triple Tray®) dual-arch trays used with vinyl polysiloxane (Flexitime®), in the putty/wash viscosity, as well as polyether (Impregum Soft®) in the regular viscosity. In one patient, an implant-level transfer was screwed on an implant in the mandibular right first molar, serving as a pattern. Ten impressions were made with each tray and impression material. The impressions were poured with Type IV gypsum. The width and height of the pattern and casts were measured in a profile projector (Nikon). The results were submitted to Student's t-test for one sample (α = 0.05). For the width distance, the plastic dual-arch trays with vinyl polysiloxane (4.513 mm) and with polyether (4.531 mm) were statistically wider than the pattern (4.489 mm). The metal dual-arch tray with vinyl polysiloxane (4.504 mm) and with polyether (4.500 mm) did not differ statistically from the pattern. For the height distance, only the metal dual-arch tray with polyether (2.253 mm) differed statistically from the pattern (2.310 mm). The metal dual-arch tray with vinyl polysiloxane, in the putty/wash viscosities, reproduced casts with less distortion in comparison with the same technique with the plastic dual-arch tray. The plastic or metal dual-arch trays with polyether reproduced cast with greater distortion. How to cite the article: Santayana de Lima LM, Borges GA, Burnett LH Jr, Spohr AM. In vivo study of the accuracy of dual-arch impressions. J Int Oral Health 2014;6(3):50-5.

  20. An Initial Study of Airport Arrival Heinz Capacity Benefits Due to Improved Scheduling Accuracy

    NASA Technical Reports Server (NTRS)

    Meyn, Larry; Erzberger, Heinz

    2005-01-01

    The long-term growth rate in air-traffic demand leads to future air-traffic densities that are unmanageable by today's air-traffic control system. I n order to accommodate such growth, new technology and operational methods will be needed in the next generation air-traffic control system. One proposal for such a system is the Automated Airspace Concept (AAC). One of the precepts of AAC is to direct aircraft using trajectories that are sent via an air-ground data link. This greatly improves the accuracy in directing aircraft to specific waypoints at specific times. Studies of the Center-TRACON Automation System (CTAS) have shown that increased scheduling accuracy enables increased arrival capacity at CTAS equipped airports.

  1. Assuring high quality treatment delivery in clinical trials - Results from the Trans-Tasman Radiation Oncology Group (TROG) study 03.04 "RADAR" set-up accuracy study.

    PubMed

    Haworth, Annette; Kearvell, Rachel; Greer, Peter B; Hooton, Ben; Denham, James W; Lamb, David; Duchesne, Gillian; Murray, Judy; Joseph, David

    2009-03-01

    A multi-centre clinical trial for prostate cancer patients provided an opportunity to introduce conformal radiotherapy with dose escalation. To verify adequate treatment accuracy prior to patient recruitment, centres submitted details of a set-up accuracy study (SUAS). We report the results of the SUAS, the variation in clinical practice and the strategies used to help centres improve treatment accuracy. The SUAS required each of the 24 participating centres to collect data on at least 10 pelvic patients imaged on a minimum of 20 occasions. Software was provided for data collection and analysis. Support to centres was provided through educational lectures, the trial quality assurance team and an information booklet. Only two centres had recently carried out a SUAS prior to the trial opening. Systematic errors were generally smaller than those previously reported in the literature. The questionnaire identified many differences in patient set-up protocols. As a result of participating in this QA activity more than 65% of centres improved their treatment delivery accuracy. Conducting a pre-trial SUAS has led to improvement in treatment delivery accuracy in many centres. Treatment techniques and set-up accuracy varied greatly, demonstrating a need to ensure an on-going awareness for such studies in future trials and with the introduction of dose escalation or new technologies.

  2. Diagnostic accuracy of the Eurotest for dementia: a naturalistic, multicenter phase II study

    PubMed Central

    Carnero-Pardo, Cristobal; Gurpegui, Manuel; Sanchez-Cantalejo, Emilio; Frank, Ana; Mola, Santiago; Barquero, M Sagrario; Montoro-Rios, M Teresa

    2006-01-01

    Background Available screening tests for dementia are of limited usefulness because they are influenced by the patient's culture and educational level. The Eurotest, an instrument based on the knowledge and handling of money, was designed to overcome these limitations. The objective of this study was to evaluate the diagnostic accuracy of the Eurotest in identifying dementia in customary clinical practice. Methods A cross-sectional, multi-center, naturalistic phase II study was conducted. The Eurotest was administered to consecutive patients, older than 60 years, in general neurology clinics. The patients' condition was classified as dementia or no dementia according to DSM-IV diagnostic criteria. We calculated sensitivity (Sn), specificity (Sp) and area under the ROC curves (aROC) with 95% confidence intervals. The influence of social and educational factors on scores was evaluated with multiple linear regression analysis, and the influence of these factors on diagnostic accuracy was evaluated with logistic regression. Results Sixteen neurologists recruited a total of 516 participants: 101 with dementia, 380 without dementia, and 35 who were excluded. Of the 481 participants who took the Eurotest, 38.7% were totally or functionally illiterate and 45.5% had received no formal education. Mean time needed to administer the test was 8.2+/-2.0 minutes. The best cut-off point was 20/21, with Sn = 0.91 (0.84–0.96), Sp = 0.82 (0.77–0.85), and aROC = 0.93 (0.91–0.95). Neither the scores on the Eurotest nor its diagnostic accuracy were influenced by social or educational factors. Conclusion This naturalistic and pragmatic study shows that the Eurotest is a rapid, simple and useful screening instrument, which is free from educational influences, and has appropriate internal and external validity. PMID:16606455

  3. Matters of Accuracy and Conventionality: Prior Accuracy Guides Children's Evaluations of Others' Actions

    ERIC Educational Resources Information Center

    Scofield, Jason; Gilpin, Ansley Tullos; Pierucci, Jillian; Morgan, Reed

    2013-01-01

    Studies show that children trust previously reliable sources over previously unreliable ones (e.g., Koenig, Clement, & Harris, 2004). However, it is unclear from these studies whether children rely on accuracy or conventionality to determine the reliability and, ultimately, the trustworthiness of a particular source. In the current study, 3- and…

  4. Comparative Accuracy Evaluation of Fine-Scale Global and Local Digital Surface Models: The Tshwane Case Study I

    NASA Astrophysics Data System (ADS)

    Breytenbach, A.

    2016-10-01

    Conducted in the City of Tshwane, South Africa, this study set about to test the accuracy of DSMs derived from different remotely sensed data locally. VHR digital mapping camera stereo-pairs, tri-stereo imagery collected by a Pléiades satellite and data detected from the Tandem-X InSAR satellite configuration were fundamental in the construction of seamless DSM products at different postings, namely 2 m, 4 m and 12 m. The three DSMs were sampled against independent control points originating from validated airborne LiDAR data. The reference surfaces were derived from the same dense point cloud at grid resolutions corresponding to those of the samples. The absolute and relative positional accuracies were computed using well-known DEM error metrics and accuracy statistics. Overall vertical accuracies were also assessed and compared across seven slope classes and nine primary land cover classes. Although all three DSMs displayed significantly more vertical errors where solid waterbodies, dense natural and/or alien woody vegetation and, in a lesser degree, urban residential areas with significant canopy cover were encountered, all three surpassed their expected positional accuracies overall.

  5. Accuracy of pulse oximetry in children.

    PubMed

    Ross, Patrick A; Newth, Christopher J L; Khemani, Robinder G

    2014-01-01

    For children with cyanotic congenital heart disease or acute hypoxemic respiratory failure, providers frequently make decisions based on pulse oximetry, in the absence of an arterial blood gas. The study objective was to measure the accuracy of pulse oximetry in the saturations from pulse oximetry (SpO2) range of 65% to 97%. This institutional review board-approved prospective, multicenter observational study in 5 PICUs included 225 mechanically ventilated children with an arterial catheter. With each arterial blood gas sample, SpO2 from pulse oximetry and arterial oxygen saturations from CO-oximetry (SaO2) were simultaneously obtained if the SpO2 was ≤ 97%. The lowest SpO2 obtained in the study was 65%. In the range of SpO2 65% to 97%, 1980 simultaneous values for SpO2 and SaO2 were obtained. The bias (SpO2 - SaO2) varied through the range of SpO2 values. The bias was greatest in the SpO2 range 81% to 85% (336 samples, median 6%, mean 6.6%, accuracy root mean squared 9.1%). SpO2 measurements were close to SaO2 in the SpO2 range 91% to 97% (901 samples, median 1%, mean 1.5%, accuracy root mean squared 4.2%). Previous studies on pulse oximeter accuracy in children present a single number for bias. This study identified that the accuracy of pulse oximetry varies significantly as a function of the SpO2 range. Saturations measured by pulse oximetry on average overestimate SaO2 from CO-oximetry in the SpO2 range of 76% to 90%. Better pulse oximetry algorithms are needed for accurate assessment of children with saturations in the hypoxemic range.

  6. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, D.; Hashmall, J.

    1994-01-01

    This paper summarizes a compilation of attitude determination accuracies attained by a number of satellites supported by the Goddard Space Flight Center Flight Dynamics Facility. The compilation is designed to assist future mission planners in choosing and placing attitude hardware and selecting the attitude determination algorithms needed to achieve given accuracy requirements. The major goal of the compilation is to indicate realistic accuracies achievable using a given sensor complement based on mission experience. It is expected that the use of actual spacecraft experience will make the study especially useful for mission design. A general description of factors influencing spacecraft attitude accuracy is presented. These factors include determination algorithms, inertial reference unit characteristics, and error sources that can affect measurement accuracy. Possible techniques for mitigating errors are also included. Brief mission descriptions are presented with the attitude accuracies attained, grouped by the sensor pairs used in attitude determination. The accuracies for inactive missions represent a compendium of missions report results, and those for active missions represent measurements of attitude residuals. Both three-axis and spin stabilized missions are included. Special emphasis is given to high-accuracy sensor pairs, such as two fixed-head star trackers (FHST's) and fine Sun sensor plus FHST. Brief descriptions of sensor design and mode of operation are included. Also included are brief mission descriptions and plots summarizing the attitude accuracy attained using various sensor complements.

  7. Real-time teleophthalmology versus face-to-face consultation: A systematic review.

    PubMed

    Tan, Irene J; Dobson, Lucy P; Bartnik, Stephen; Muir, Josephine; Turner, Angus W

    2017-08-01

    Introduction Advances in imaging capabilities and the evolution of real-time teleophthalmology have the potential to provide increased coverage to areas with limited ophthalmology services. However, there is limited research assessing the diagnostic accuracy of face-to-face teleophthalmology consultation. This systematic review aims to determine if real-time teleophthalmology provides comparable accuracy to face-to-face consultation for the diagnosis of common eye health conditions. Methods A search of PubMed, Embase, Medline and Cochrane databases and manual citation review was conducted on 6 February and 7 April 2016. Included studies involved real-time telemedicine in the field of ophthalmology or optometry, and assessed diagnostic accuracy against gold-standard face-to-face consultation. The revised quality assessment of diagnostic accuracy studies (QUADAS-2) tool assessed risk of bias. Results Twelve studies were included, with participants ranging from four to 89 years old. A broad number of conditions were assessed and include corneal and retinal pathologies, strabismus, oculoplastics and post-operative review. Quality assessment identified a high or unclear risk of bias in patient selection (75%) due to an undisclosed recruitment processes. The index test showed high risk of bias in the included studies, due to the varied interpretation and conduct of real-time teleophthalmology methods. Reference standard risk was overall low (75%), as was the risk due to flow and timing (75%). Conclusion In terms of diagnostic accuracy, real-time teleophthalmology was considered superior to face-to-face consultation in one study and comparable in six studies. Store-and-forward image transmission coupled with real-time videoconferencing is a suitable alternative to overcome poor internet transmission speeds.

  8. The Effects of Alcohol Intoxication on Accuracy and the Confidence–Accuracy Relationship in Photographic Simultaneous Line‐ups

    PubMed Central

    Colloff, Melissa F.; Karoğlu, Nilda; Zelek, Katarzyna; Ryder, Hannah; Humphries, Joyce E.; Takarangi, Melanie K.T.

    2017-01-01

    Summary Acute alcohol intoxication during encoding can impair subsequent identification accuracy, but results across studies have been inconsistent, with studies often finding no effect. Little is also known about how alcohol intoxication affects the identification confidence–accuracy relationship. We randomly assigned women (N = 153) to consume alcohol (dosed to achieve a 0.08% blood alcohol content) or tonic water, controlling for alcohol expectancy. Women then participated in an interactive hypothetical sexual assault scenario and, 24 hours or 7 days later, attempted to identify the assailant from a perpetrator present or a perpetrator absent simultaneous line‐up and reported their decision confidence. Overall, levels of identification accuracy were similar across the alcohol and tonic water groups. However, women who had consumed tonic water as opposed to alcohol identified the assailant with higher confidence on average. Further, calibration analyses suggested that confidence is predictive of accuracy regardless of alcohol consumption. The theoretical and applied implications of our results are discussed.© 2017 The Authors Applied Cognitive Psychology Published by John Wiley & Sons Ltd. PMID:28781426

  9. Accuracy evaluation of intraoral optical impressions: A clinical study using a reference appliance.

    PubMed

    Atieh, Mohammad A; Ritter, André V; Ko, Ching-Chang; Duqum, Ibrahim

    2017-09-01

    Trueness and precision are used to evaluate the accuracy of intraoral optical impressions. Although the in vivo precision of intraoral optical impressions has been reported, in vivo trueness has not been evaluated because of limitations in the available protocols. The purpose of this clinical study was to compare the accuracy (trueness and precision) of optical and conventional impressions by using a novel study design. Five study participants consented and were enrolled. For each participant, optical and conventional (vinylsiloxanether) impressions of a custom-made intraoral Co-Cr alloy reference appliance fitted to the mandibular arch were obtained by 1 operator. Three-dimensional (3D) digital models were created for stone casts obtained from the conventional impression group and for the reference appliances by using a validated high-accuracy reference scanner. For the optical impression group, 3D digital models were obtained directly from the intraoral scans. The total mean trueness of each impression system was calculated by averaging the mean absolute deviations of the impression replicates from their 3D reference model for each participant, followed by averaging the obtained values across all participants. The total mean precision for each impression system was calculated by averaging the mean absolute deviations between all the impression replicas for each participant (10 pairs), followed by averaging the obtained values across all participants. Data were analyzed using repeated measures ANOVA (α=.05), first to assess whether a systematic difference in trueness or precision of replicate impressions could be found among participants and second to assess whether the mean trueness and precision values differed between the 2 impression systems. Statistically significant differences were found between the 2 impression systems for both mean trueness (P=.010) and mean precision (P=.007). Conventional impressions had higher accuracy with a mean trueness of 17.0

  10. Compensation of kinematic geometric parameters error and comparative study of accuracy testing for robot

    NASA Astrophysics Data System (ADS)

    Du, Liang; Shi, Guangming; Guan, Weibin; Zhong, Yuansheng; Li, Jin

    2014-12-01

    Geometric error is the main error of the industrial robot, and it plays a more significantly important fact than other error facts for robot. The compensation model of kinematic error is proposed in this article. Many methods can be used to test the robot accuracy, therefore, how to compare which method is better one. In this article, a method is used to compare two methods for robot accuracy testing. It used Laser Tracker System (LTS) and Three Coordinate Measuring instrument (TCM) to test the robot accuracy according to standard. According to the compensation result, it gets the better method which can improve the robot accuracy apparently.

  11. Insensitivity of the octahedral spherical hohlraum to power imbalance, pointing accuracy, and assemblage accuracy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Huo, Wen Yi; Zhao, Yiqing; Zheng, Wudi

    2014-11-15

    The random radiation asymmetry in the octahedral spherical hohlraum [K. Lan et al., Phys. Plasmas 21, 0 10704 (2014)] arising from the power imbalance, pointing accuracy of laser quads, and the assemblage accuracy of capsule is investigated by using the 3-dimensional view factor model. From our study, for the spherical hohlraum, the random radiation asymmetry arising from the power imbalance of the laser quads is about half of that in the cylindrical hohlraum; the random asymmetry arising from the pointing error is about one order lower than that in the cylindrical hohlraum; and the random asymmetry arising from the assemblage errormore » of capsule is about one third of that in the cylindrical hohlraum. Moreover, the random radiation asymmetry in the spherical hohlraum is also less than the amount in the elliptical hohlraum. The results indicate that the spherical hohlraum is more insensitive to the random variations than the cylindrical hohlraum and the elliptical hohlraum. Hence, the spherical hohlraum can relax the requirements to the power imbalance and pointing accuracy of laser facility and the assemblage accuracy of capsule.« less

  12. Accuracy testing of electric groundwater-level measurement tapes

    USGS Publications Warehouse

    Jelinski, Jim; Clayton, Christopher S.; Fulford, Janice M.

    2015-01-01

    The accuracy tests demonstrated that none of the electric-tape models tested consistently met the suggested USGS accuracy of ±0.01 ft. The test data show that the tape models in the study should give a water-level measurement that is accurate to roughly ±0.05 ft per 100 ft without additional calibration. To meet USGS accuracy guidelines, the electric-tape models tested will need to be individually calibrated. Specific conductance also plays a part in tape accuracy. The probes will not work in water with specific conductance values near zero, and the accuracy of one probe was unreliable in very high conductivity water (10,000 microsiemens per centimeter).

  13. Diagnostic accuracy of a clinical diagnosis of idiopathic pulmonary fibrosis: an international case–cohort study

    PubMed Central

    Maher, Toby M.; Kolb, Martin; Poletti, Venerino; Nusser, Richard; Richeldi, Luca; Vancheri, Carlo; Wilsher, Margaret L.; Antoniou, Katerina M.; Behr, Jüergen; Bendstrup, Elisabeth; Brown, Kevin; Calandriello, Lucio; Corte, Tamera J.; Crestani, Bruno; Flaherty, Kevin; Glaspole, Ian; Grutters, Jan; Inoue, Yoshikazu; Kokosi, Maria; Kondoh, Yasuhiro; Kouranos, Vasileios; Kreuter, Michael; Johannson, Kerri; Judge, Eoin; Ley, Brett; Margaritopoulos, George; Martinez, Fernando J.; Molina-Molina, Maria; Morais, António; Nunes, Hilario; Raghu, Ganesh; Ryerson, Christopher J.; Selman, Moises; Spagnolo, Paolo; Taniguchi, Hiroyuki; Tomassetti, Sara; Valeyre, Dominique; Wijsenbeek, Marlies; Wuyts, Wim; Hansell, David; Wells, Athol

    2017-01-01

    We conducted an international study of idiopathic pulmonary fibrosis (IPF) diagnosis among a large group of physicians and compared their diagnostic performance to a panel of IPF experts. A total of 1141 respiratory physicians and 34 IPF experts participated. Participants evaluated 60 cases of interstitial lung disease (ILD) without interdisciplinary consultation. Diagnostic agreement was measured using the weighted kappa coefficient (κw). Prognostic discrimination between IPF and other ILDs was used to validate diagnostic accuracy for first-choice diagnoses of IPF and were compared using the C-index. A total of 404 physicians completed the study. Agreement for IPF diagnosis was higher among expert physicians (κw=0.65, IQR 0.53–0.72, p<0.0001) than academic physicians (κw=0.56, IQR 0.45–0.65, p<0.0001) or physicians with access to multidisciplinary team (MDT) meetings (κw=0.54, IQR 0.45–0.64, p<0.0001). The prognostic accuracy of academic physicians with >20 years of experience (C-index=0.72, IQR 0.0–0.73, p=0.229) and non-university hospital physicians with more than 20 years of experience, attending weekly MDT meetings (C-index=0.72, IQR 0.70–0.72, p=0.052), did not differ significantly (p=0.229 and p=0.052 respectively) from the expert panel (C-index=0.74 IQR 0.72–0.75). Experienced respiratory physicians at university-based institutions diagnose IPF with similar prognostic accuracy to IPF experts. Regular MDT meeting attendance improves the prognostic accuracy of experienced non-university practitioners to levels achieved by IPF experts. PMID:28860269

  14. In vivo study of flow-rate accuracy of the MedStream Programmable Infusion System.

    PubMed

    Venugopalan, Ramakrishna; Ginggen, Alec; Bork, Toralf; Anderson, William; Buffen, Elaine

    2011-01-01

      Flow-rate accuracy and precision are important parameters to optimizing the efficacy of programmable intrathecal (IT) infusion pump delivery systems. Current programmable IT pumps are accurate within ±14.5% of their programmed infusion rate when assessed under ideal environmental conditions and specific flow-rate settings in vitro. We assessed the flow-rate accuracy of a novel programmable pump system across its entire flow-rate range under typical conditions in sheep (in vivo) and nominal conditions in vitro.   The flow-rate accuracy of the MedStream Programmable Pump was assessed in both the in vivo and in vitro settings. In vivo flow-rate accuracy was assessed in 16 sheep at various flow-rates (producing 90 flow intervals) more than 90 ± 3 days. Pumps were then explanted, re-sterilized and in vitro flow-rate accuracy was assessed at 37°C and 1013 mBar (80 flow intervals).   In vivo (sheep body temperatures 38.1°C-39.8°C), mean ± SD flow-rate error was 9.32% ± 9.27% and mean ± SD leak-rate was 0.028 ± 0.08 mL/day. Following explantation, mean in vitro flow-rate error and leak-rate were -1.05% ± 2.55% and 0.003 ± 0.004 mL/day (37°C, 1013 mBar), respectively.   The MedStream Programmable Pump demonstrated high flow-rate accuracy when tested in vivo and in vitro at normal body temperature and environmental pressure as well as when tested in vivo at variable sheep body temperature. The flow-rate accuracy of the MedStream Programmable Pump across its flow-rate range, compares favorably to the accuracy of current clinically utilized programmable IT infusion pumps reported at specific flow-rate settings and conditions. © 2011 International Neuromodulation Society.

  15. Case studies on forecasting for innovative technologies: frequent revisions improve accuracy.

    PubMed

    Lerner, Jeffrey C; Robertson, Diane C; Goldstein, Sara M

    2015-02-01

    Health technology forecasting is designed to provide reliable predictions about costs, utilization, diffusion, and other market realities before the technologies enter routine clinical use. In this article we address three questions central to forecasting's usefulness: Are early forecasts sufficiently accurate to help providers acquire the most promising technology and payers to set effective coverage policies? What variables contribute to inaccurate forecasts? How can forecasters manage the variables to improve accuracy? We analyzed forecasts published between 2007 and 2010 by the ECRI Institute on four technologies: single-room proton beam radiation therapy for various cancers; digital breast tomosynthesis imaging technology for breast cancer screening; transcatheter aortic valve replacement for serious heart valve disease; and minimally invasive robot-assisted surgery for various cancers. We then examined revised ECRI forecasts published in 2013 (digital breast tomosynthesis) and 2014 (the other three topics) to identify inaccuracies in the earlier forecasts and explore why they occurred. We found that five of twenty early predictions were inaccurate when compared with the updated forecasts. The inaccuracies pertained to two technologies that had more time-sensitive variables to consider. The case studies suggest that frequent revision of forecasts could improve accuracy, especially for complex technologies whose eventual use is governed by multiple interactive factors. Project HOPE—The People-to-People Health Foundation, Inc.

  16. Diagnosis of rotator cuff tears using 3-Tesla MRI versus 3-Tesla MRA: a systematic review and meta-analysis.

    PubMed

    McGarvey, Ciaran; Harb, Ziad; Smith, Christian; Houghton, Russell; Corbett, Steven; Ajuied, Adil

    2016-02-01

    To compare the diagnostic accuracy of magnetic resonance imaging (MRI), 2-dimensional magnetic resonance arthrogram (MRA) and 3-dimensional isotropic MRA in the diagnosis of rotator cuff tears when performed exclusively at 3-T. A systematic review was undertaken of the Cochrane, MEDLINE and PubMed databases in accordance with the PRISMA guidelines. Studies comparing 3-T MRI or 3-T MRA (index tests) to arthroscopic surgical findings (reference test) were included. Methodological appraisal was performed using QUADAS 2. Pooled sensitivity and specificity were calculated and summary receiver-operating curves generated. Kappa coefficients quantified inter-observer reliability. Fourteen studies comprising 1332 patients were identified for inclusion. Twelve studies were retrospective and there were concerns regarding index test bias and applicability in nine and six studies respectively. Reference test bias was a concern in all studies. Both 3-T MRI and 3-T MRA showed similar excellent diagnostic accuracy for full-thickness supraspinatus tears. Concerning partial-thickness supraspinatus tears, 3-T 2D MRA was significantly more sensitive (86.6 vs. 80.5 %, p = 0.014) but significantly less specific (95.2 vs. 100 %, p < 0.001). There was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA showed similar accuracy to 3-T conventional 2D MRA. Three-Tesla MRI appeared equivalent to 3-T MRA in the diagnosis of full- and partial-thickness tears, although there was a trend towards greater accuracy in the diagnosis of subscapularis tears with 3-T MRA. Three-Tesla 3D isotropic MRA appears equivalent to 3-T 2D MRA for all types of tears.

  17. Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?

    PubMed Central

    Cacho-Martínez, Pilar; García-Muñoz, Ángel; Ruiz-Cantero, María Teresa

    2013-01-01

    Purpose To analyze the diagnostic criteria used in the scientific literature published in the past 25 years for accommodative and nonstrabismic binocular dysfunctions and to explore if the epidemiological analysis of diagnostic validity has been used to propose which clinical criteria should be used for diagnostic purposes. Methods We carried out a systematic review of papers on accommodative and non-strabic binocular disorders published from 1986 to 2012 analysing the MEDLINE, CINAHL, PsycINFO and FRANCIS databases. We admitted original articles about diagnosis of these anomalies in any population. We identified 839 articles and 12 studies were included. The quality of included articles was assessed using the QUADAS-2 tool. Results The review shows a wide range of clinical signs and cut-off points between authors. Only 3 studies (regarding accommodative anomalies) assessed diagnostic accuracy of clinical signs. Their results suggest using the accommodative amplitude and monocular accommodative facility for diagnosing accommodative insufficiency and a high positive relative accommodation for accommodative excess. The remaining 9 articles did not analyze diagnostic accuracy, assessing a diagnosis with the criteria the authors considered. We also found differences between studies in the way of considering patients’ symptomatology. 3 studies of 12 analyzed, performed a validation of a symptom survey used for convergence insufficiency. Conclusions Scientific literature reveals differences between authors according to diagnostic criteria for accommodative and nonstrabismic binocular dysfunctions. Diagnostic accuracy studies show that there is only certain evidence for accommodative conditions. For binocular anomalies there is only evidence about a validated questionnaire for convergence insufficiency with no data of diagnostic accuracy. PMID:24646897

  18. Physical examination tests for the diagnosis of posterior cruciate ligament rupture: a systematic review.

    PubMed

    Kopkow, Christian; Freiberg, Alice; Kirschner, Stephan; Seidler, Andreas; Schmitt, Jochen

    2013-11-01

    Systematic literature review. To summarize and evaluate research on the accuracy of physical examination tests for diagnosis of posterior cruciate ligament (PCL) tear. Rupture of the PCL is a severe knee injury that can lead to delayed rehabilitation, instability, or chronic knee pathologies. To our knowledge, there is currently no systematic review of studies on the diagnostic accuracy of clinical examination tests to evaluate the integrity of the PCL. A comprehensive systematic literature search was conducted in MEDLINE from 1946, Embase from 1974, and the Allied and Complementary Medicine Database from 1985 until April 30, 2012. Studies were considered eligible if they compared the results of physical examination tests performed in the context of a PCL physical examination to those of a reference standard (arthroscopy, arthrotomy, magnetic resonance imaging). Methodological quality assessment was performed by 2 independent reviewers using the revised version of the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The search strategy revealed 1307 articles, of which 11 met the inclusion criteria for this review. In these studies, 11 different physical examination tests were identified. Due to differences in study types, different patient populations, and methodological quality, meta-analysis was not indicated. Presently, most physical examination tests have not been evaluated sufficiently enough to be confident in their ability to either confirm or rule out a PCL tear. The diagnostic accuracy of physical examination tests to assess the integrity of the PCL is largely unknown. There is a strong need for further research in this area. Level of Evidence Diagnosis, level 3a.

  19. Effects of Problem Solving after Worked Example Study on Secondary School Children's Monitoring Accuracy

    ERIC Educational Resources Information Center

    Baars, Martine; van Gog, Tamara; de Bruin, Anique; Paas, Fred

    2017-01-01

    Monitoring accuracy, measured by judgements of learning (JOLs), has generally been found to be low to moderate, with students often displaying overconfidence, and JOLs of problem solving are no exception. Recently, primary school children's overconfidence was shown to diminish when they practised problem solving after studying worked examples. The…

  20. Overlay accuracy fundamentals

    NASA Astrophysics Data System (ADS)

    Kandel, Daniel; Levinski, Vladimir; Sapiens, Noam; Cohen, Guy; Amit, Eran; Klein, Dana; Vakshtein, Irina

    2012-03-01

    Currently, the performance of overlay metrology is evaluated mainly based on random error contributions such as precision and TIS variability. With the expected shrinkage of the overlay metrology budget to < 0.5nm, it becomes crucial to include also systematic error contributions which affect the accuracy of the metrology. Here we discuss fundamental aspects of overlay accuracy and a methodology to improve accuracy significantly. We identify overlay mark imperfections and their interaction with the metrology technology, as the main source of overlay inaccuracy. The most important type of mark imperfection is mark asymmetry. Overlay mark asymmetry leads to a geometrical ambiguity in the definition of overlay, which can be ~1nm or less. It is shown theoretically and in simulations that the metrology may enhance the effect of overlay mark asymmetry significantly and lead to metrology inaccuracy ~10nm, much larger than the geometrical ambiguity. The analysis is carried out for two different overlay metrology technologies: Imaging overlay and DBO (1st order diffraction based overlay). It is demonstrated that the sensitivity of DBO to overlay mark asymmetry is larger than the sensitivity of imaging overlay. Finally, we show that a recently developed measurement quality metric serves as a valuable tool for improving overlay metrology accuracy. Simulation results demonstrate that the accuracy of imaging overlay can be improved significantly by recipe setup optimized using the quality metric. We conclude that imaging overlay metrology, complemented by appropriate use of measurement quality metric, results in optimal overlay accuracy.

  1. Improved imputation accuracy in Hispanic/Latino populations with larger and more diverse reference panels: applications in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL)

    PubMed Central

    Nelson, Sarah C.; Stilp, Adrienne M.; Papanicolaou, George J.; Taylor, Kent D.; Rotter, Jerome I.; Thornton, Timothy A.; Laurie, Cathy C.

    2016-01-01

    Imputation is commonly used in genome-wide association studies to expand the set of genetic variants available for analysis. Larger and more diverse reference panels, such as the final Phase 3 of the 1000 Genomes Project, hold promise for improving imputation accuracy in genetically diverse populations such as Hispanics/Latinos in the USA. Here, we sought to empirically evaluate imputation accuracy when imputing to a 1000 Genomes Phase 3 versus a Phase 1 reference, using participants from the Hispanic Community Health Study/Study of Latinos. Our assessments included calculating the correlation between imputed and observed allelic dosage in a subset of samples genotyped on a supplemental array. We observed that the Phase 3 reference yielded higher accuracy at rare variants, but that the two reference panels were comparable at common variants. At a sample level, the Phase 3 reference improved imputation accuracy in Hispanic/Latino samples from the Caribbean more than for Mainland samples, which we attribute primarily to the additional reference panel samples available in Phase 3. We conclude that a 1000 Genomes Project Phase 3 reference panel can yield improved imputation accuracy compared with Phase 1, particularly for rare variants and for samples of certain genetic ancestry compositions. Our findings can inform imputation design for other genome-wide association studies of participants with diverse ancestries, especially as larger and more diverse reference panels continue to become available. PMID:27346520

  2. The Eye Phone Study: reliability and accuracy of assessing Snellen visual acuity using smartphone technology

    PubMed Central

    Perera, C; Chakrabarti, R; Islam, F M A; Crowston, J

    2015-01-01

    Purpose Smartphone-based Snellen visual acuity charts has become popularized; however, their accuracy has not been established. This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart. Methods First, a review of available Snellen chart applications on iPhone was performed to determine the most accurate application based on optotype size. Subsequently, a prospective comparative study was performed by measuring conventional 6SVA and then iPhone visual acuity using the ‘Snellen' application on an Apple iPhone 4. Results Eleven applications were identified, with accuracy of optotype size ranging from 4.4–39.9%. Eighty-eight patients from general medical and surgical wards in a tertiary hospital took part in the second part of the study. The mean difference in logMAR visual acuity between the two charts was 0.02 logMAR (95% limit of agreement −0.332, 0.372 logMAR). The largest mean difference in logMAR acuity was noted in the subgroup of patients with 6SVA worse than 6/18 (n=5), who had a mean difference of two Snellen visual acuity lines between the charts (0.276 logMAR). Conclusion We did not identify a Snellen visual acuity app at the time of study, which could predict a patients standard Snellen visual acuity within one line. There was considerable variability in the optotype accuracy of apps. Further validation is required for assessment of acuity in patients with severe vision impairment. PMID:25931170

  3. Increasing Deception Detection Accuracy with Strategic Questioning

    ERIC Educational Resources Information Center

    Levine, Timothy R.; Shaw, Allison; Shulman, Hillary C.

    2010-01-01

    One explanation for the finding of slightly above-chance accuracy in detecting deception experiments is limited variance in sender transparency. The current study sought to increase accuracy by increasing variance in sender transparency with strategic interrogative questioning. Participants (total N = 128) observed cheaters and noncheaters who…

  4. Inertial Measures of Motion for Clinical Biomechanics: Comparative Assessment of Accuracy under Controlled Conditions – Changes in Accuracy over Time

    PubMed Central

    Lebel, Karina; Boissy, Patrick; Hamel, Mathieu; Duval, Christian

    2015-01-01

    Background Interest in 3D inertial motion tracking devices (AHRS) has been growing rapidly among the biomechanical community. Although the convenience of such tracking devices seems to open a whole new world of possibilities for evaluation in clinical biomechanics, its limitations haven’t been extensively documented. The objectives of this study are: 1) to assess the change in absolute and relative accuracy of multiple units of 3 commercially available AHRS over time; and 2) to identify different sources of errors affecting AHRS accuracy and to document how they may affect the measurements over time. Methods This study used an instrumented Gimbal table on which AHRS modules were carefully attached and put through a series of velocity-controlled sustained motions including 2 minutes motion trials (2MT) and 12 minutes multiple dynamic phases motion trials (12MDP). Absolute accuracy was assessed by comparison of the AHRS orientation measurements to those of an optical gold standard. Relative accuracy was evaluated using the variation in relative orientation between modules during the trials. Findings Both absolute and relative accuracy decreased over time during 2MT. 12MDP trials showed a significant decrease in accuracy over multiple phases, but accuracy could be enhanced significantly by resetting the reference point and/or compensating for initial Inertial frame estimation reference for each phase. Interpretation The variation in AHRS accuracy observed between the different systems and with time can be attributed in part to the dynamic estimation error, but also and foremost, to the ability of AHRS units to locate the same Inertial frame. Conclusions Mean accuracies obtained under the Gimbal table sustained conditions of motion suggest that AHRS are promising tools for clinical mobility assessment under constrained conditions of use. However, improvement in magnetic compensation and alignment between AHRS modules are desirable in order for AHRS to reach their

  5. The accuracy of pulse oximetry in emergency department patients with severe sepsis and septic shock: a retrospective cohort study.

    PubMed

    Wilson, Ben J; Cowan, Hamish J; Lord, Jason A; Zuege, Dan J; Zygun, David A

    2010-05-05

    Pulse oximetry is routinely used to continuously and noninvasively monitor arterial oxygen saturation (SaO2) in critically ill patients. Although pulse oximeter oxygen saturation (SpO2) has been studied in several patient populations, including the critically ill, its accuracy has never been studied in emergency department (ED) patients with severe sepsis and septic shock. Sepsis results in characteristic microcirculatory derangements that could theoretically affect pulse oximeter accuracy. The purposes of the present study were twofold: 1) to determine the accuracy of pulse oximetry relative to SaO2 obtained from ABG in ED patients with severe sepsis and septic shock, and 2) to assess the impact of specific physiologic factors on this accuracy. This analysis consisted of a retrospective cohort of 88 consecutive ED patients with severe sepsis who had a simultaneous arterial blood gas and an SpO2 value recorded. Adult ICU patients that were admitted from any Calgary Health Region adult ED with a pre-specified, sepsis-related admission diagnosis between October 1, 2005 and September 30, 2006, were identified. Accuracy (SpO2 - SaO2) was analyzed by the method of Bland and Altman. The effects of hypoxemia, acidosis, hyperlactatemia, anemia, and the use of vasoactive drugs on bias were determined. The cohort consisted of 88 subjects, with a mean age of 57 years (19 - 89). The mean difference (SpO2 - SaO2) was 2.75% and the standard deviation of the differences was 3.1%. Subgroup analysis demonstrated that hypoxemia (SaO2 < 90) significantly affected pulse oximeter accuracy. The mean difference was 4.9% in hypoxemic patients and 1.89% in non-hypoxemic patients (p < 0.004). In 50% (11/22) of cases in which SpO2 was in the 90-93% range the SaO2 was <90%. Though pulse oximeter accuracy was not affected by acidoisis, hyperlactatementa, anemia or vasoactive drugs, these factors worsened precision. Pulse oximetry overestimates ABG-determined SaO2 by a mean of 2.75% in

  6. Cadastral Database Positional Accuracy Improvement

    NASA Astrophysics Data System (ADS)

    Hashim, N. M.; Omar, A. H.; Ramli, S. N. M.; Omar, K. M.; Din, N.

    2017-10-01

    Positional Accuracy Improvement (PAI) is the refining process of the geometry feature in a geospatial dataset to improve its actual position. This actual position relates to the absolute position in specific coordinate system and the relation to the neighborhood features. With the growth of spatial based technology especially Geographical Information System (GIS) and Global Navigation Satellite System (GNSS), the PAI campaign is inevitable especially to the legacy cadastral database. Integration of legacy dataset and higher accuracy dataset like GNSS observation is a potential solution for improving the legacy dataset. However, by merely integrating both datasets will lead to a distortion of the relative geometry. The improved dataset should be further treated to minimize inherent errors and fitting to the new accurate dataset. The main focus of this study is to describe a method of angular based Least Square Adjustment (LSA) for PAI process of legacy dataset. The existing high accuracy dataset known as National Digital Cadastral Database (NDCDB) is then used as bench mark to validate the results. It was found that the propose technique is highly possible for positional accuracy improvement of legacy spatial datasets.

  7. A Comparative Study of Precise Point Positioning (PPP) Accuracy Using Online Services

    NASA Astrophysics Data System (ADS)

    Malinowski, Marcin; Kwiecień, Janusz

    2016-12-01

    Precise Point Positioning (PPP) is a technique used to determine the position of receiver antenna without communication with the reference station. It may be an alternative solution to differential measurements, where maintaining a connection with a single RTK station or a regional network of reference stations RTN is necessary. This situation is especially common in areas with poorly developed infrastructure of ground stations. A lot of research conducted so far on the use of the PPP technique has been concerned about the development of entire day observation sessions. However, this paper presents the results of a comparative analysis of accuracy of absolute determination of position from observations which last between 1 to 7 hours with the use of four permanent services which execute calculations with PPP technique such as: Automatic Precise Positioning Service (APPS), Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP), GNSS Analysis and Positioning Software (GAPS) and magicPPP - Precise Point Positioning Solution (magicGNSS). On the basis of acquired results of measurements, it can be concluded that at least two-hour long measurements allow acquiring an absolute position with an accuracy of 2-4 cm. An evaluation of the impact on the accuracy of simultaneous positioning of three points test network on the change of the horizontal distance and the relative height difference between measured triangle vertices was also conducted. Distances and relative height differences between points of the triangular test network measured with a laser station Leica TDRA6000 were adopted as references. The analyses of results show that at least two hours long measurement sessions can be used to determine the horizontal distance or the difference in height with an accuracy of 1-2 cm. Rapid products employed in calculations conducted with PPP technique reached the accuracy of determining coordinates on a close level as in elaborations which employ Final products.

  8. Confirmatory Tests for the Diagnosis of Primary Aldosteronism: A Prospective Diagnostic Accuracy Study.

    PubMed

    Song, Ying; Yang, Shumin; He, Wenwen; Hu, Jinbo; Cheng, Qingfeng; Wang, Yue; Luo, Ting; Ma, Linqiang; Zhen, Qianna; Zhang, Suhua; Mei, Mei; Wang, Zhihong; Qing, Hua; Bruemmer, Dennis; Peng, Bin; Li, Qifu

    2018-01-01

    The diagnosis of primary aldosteronism typically requires at least one confirmatory test. The fludrocortisone suppression test is generally accepted as a reliable confirmatory test, but it is cumbersome. Evidence from accuracy studies of the saline infusion test (SIT) and the captopril challenge test (CCT) has provided conflicting results. This prospective study aimed to evaluate the diagnostic accuracy of the SIT and CCT using fludrocortisone suppression test as the reference standard. One hundred thirty-five patients diagnosed with primary aldosteronism and 101 patients diagnosed with essential hypertension who completed the 3 confirmatory tests were included for the diagnostic accuracy analysis. The areas under the receiver-operator characteristics curves of the CCT and SIT were 0.96 (95% confidence interval [CI], 0.92-0.98) and 0.96 (95% CI, 0.92-0.98), respectively, using post-test plasma aldosterone concentration (PAC) for diagnosis. However, the areas under the receiver-operator characteristics curves of the CCT decreased to 0.71 (95% CI, 0.65-0.77) when the PAC suppression percentage was used to diagnose primary aldosteronism. The optimal cutoff of PAC post-CCT was set at 11 ng/dL, resulting in a sensitivity of 0.90 (95% CI, 0.84-0.95) and a specificity of 0.90 (95% CI, 0.83-0.95), which were not significantly different from those of SIT (with PAC post-SIT set at 8 ng/dL, sensitivity: 0.85 [95% CI, 0.78-0.91], P =0.192; specificity: 0.92 [95% CI, 0.85-0.97], P =0.551). In conclusion, both CCT and SIT are accurate alternatives to the more complex fludrocortisone suppression test. Because CCT is safe and much easier to perform, it may serve as a more feasible alternative. When interpreting the results of CCT, PAC post-CCT is highly recommended. © 2017 American Heart Association, Inc.

  9. A reference dataset for deformable image registration spatial accuracy evaluation using the COPDgene study archive

    NASA Astrophysics Data System (ADS)

    Castillo, Richard; Castillo, Edward; Fuentes, David; Ahmad, Moiz; Wood, Abbie M.; Ludwig, Michelle S.; Guerrero, Thomas

    2013-05-01

    Landmark point-pairs provide a strategy to assess deformable image registration (DIR) accuracy in terms of the spatial registration of the underlying anatomy depicted in medical images. In this study, we propose to augment a publicly available database (www.dir-lab.com) of medical images with large sets of manually identified anatomic feature pairs between breath-hold computed tomography (BH-CT) images for DIR spatial accuracy evaluation. Ten BH-CT image pairs were randomly selected from the COPDgene study cases. Each patient had received CT imaging of the entire thorax in the supine position at one-fourth dose normal expiration and maximum effort full dose inspiration. Using dedicated in-house software, an imaging expert manually identified large sets of anatomic feature pairs between images. Estimates of inter- and intra-observer spatial variation in feature localization were determined by repeat measurements of multiple observers over subsets of randomly selected features. 7298 anatomic landmark features were manually paired between the 10 sets of images. Quantity of feature pairs per case ranged from 447 to 1172. Average 3D Euclidean landmark displacements varied substantially among cases, ranging from 12.29 (SD: 6.39) to 30.90 (SD: 14.05) mm. Repeat registration of uniformly sampled subsets of 150 landmarks for each case yielded estimates of observer localization error, which ranged in average from 0.58 (SD: 0.87) to 1.06 (SD: 2.38) mm for each case. The additions to the online web database (www.dir-lab.com) described in this work will broaden the applicability of the reference data, providing a freely available common dataset for targeted critical evaluation of DIR spatial accuracy performance in multiple clinical settings. Estimates of observer variance in feature localization suggest consistent spatial accuracy for all observers across both four-dimensional CT and COPDgene patient cohorts.

  10. The Evaluation of Bivariate Mixed Models in Meta-analyses of Diagnostic Accuracy Studies with SAS, Stata and R.

    PubMed

    Vogelgesang, Felicitas; Schlattmann, Peter; Dewey, Marc

    2018-05-01

    Meta-analyses require a thoroughly planned procedure to obtain unbiased overall estimates. From a statistical point of view not only model selection but also model implementation in the software affects the results. The present simulation study investigates the accuracy of different implementations of general and generalized bivariate mixed models in SAS (using proc mixed, proc glimmix and proc nlmixed), Stata (using gllamm, xtmelogit and midas) and R (using reitsma from package mada and glmer from package lme4). Both models incorporate the relationship between sensitivity and specificity - the two outcomes of interest in meta-analyses of diagnostic accuracy studies - utilizing random effects. Model performance is compared in nine meta-analytic scenarios reflecting the combination of three sizes for meta-analyses (89, 30 and 10 studies) with three pairs of sensitivity/specificity values (97%/87%; 85%/75%; 90%/93%). The evaluation of accuracy in terms of bias, standard error and mean squared error reveals that all implementations of the generalized bivariate model calculate sensitivity and specificity estimates with deviations less than two percentage points. proc mixed which together with reitsma implements the general bivariate mixed model proposed by Reitsma rather shows convergence problems. The random effect parameters are in general underestimated. This study shows that flexibility and simplicity of model specification together with convergence robustness should influence implementation recommendations, as the accuracy in terms of bias was acceptable in all implementations using the generalized approach. Schattauer GmbH.

  11. Task-Based Variability in Children's Singing Accuracy

    ERIC Educational Resources Information Center

    Nichols, Bryan E.

    2013-01-01

    The purpose of this study was to explore task-based variability in children's singing accuracy performance. The research questions were: Does children's singing accuracy vary based on the nature of the singing assessment employed? Is there a hierarchy of difficulty and discrimination ability among singing assessment tasks? What is the…

  12. Accuracy of implant surgery with surgical guide by inexperienced clinicians: an in vitro study

    PubMed Central

    Tanaka, Hideaki; Sasaki, Masanori; Ichimaru, Eiji; Naito, Yasushi; Matsushita, Yasuyuki; Koyano, Kiyoshi; Nakamura, Seiji

    2015-01-01

    Abstract Implant surgery with surgical guide has been introduced with a concept of position improvement. The surgery might be considered as easy even for inexperienced clinician because of step simplicity. However, there are residual risks, resulting in postoperative complications. The aim of this study was to assess the accuracy of implant surgery with surgical guide by inexperienced clinicians in in vitro. After preoperative computed tomographies (CTs) of five artificial models of unilateral free‐end edentulism with scan templates, five surgical guides were established from templates. Following virtual planning, 10 implants were placed in the 45 and 47 regions by five residents without any placement experiences. All drillings and placements were performed using surgical guides. After postoperative CTs, inaccurate verifications between virtual and actual positions of implants were carried out, by overlaying of pre/postoperative CT data. The angle displacement of implant axis in the 47 region was significantly larger than that in the 45 region (P = 0.031). The 3D offset of implant base in the 47 region was significantly larger than that in the 45 region (P = 0.002). For distal/apical directions, displacements of base in the 47 region were significantly larger than those in the 45 region (P = 0.004 and P = 0.003, respectively). The 3D offset of implant tip in the 47 region was significantly larger than that in the 45 region (P = 0.003). For distal/apical directions, displacements of tip in the 47 region were significantly larger than those in the 45 region (P = 0.002 and P = 0.003, respectively). Within limitations of this in vitro study, data for accuracy of implant surgery with surgical guide would be informative for further studies, because in vitro studies should be substantially made to avoid unnecessary burden of patients, in advance of retro/prospective studies. A comparison of the accuracy in this in vitro model between by

  13. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., measurement accuracy, and cut-off. 53.53 Section 53.53 Protection of Environment ENVIRONMENTAL PROTECTION..., measurement accuracy, and cut-off. (a) Overview. This test procedure is designed to evaluate a candidate... measurement accuracy, coefficient of variability measurement accuracy, and the flow rate cut-off function. The...

  14. Investigating the spatial accuracy of CBCT-guided cranial radiosurgery: A phantom end-to-end test study.

    PubMed

    Calvo-Ortega, Juan-Francisco; Hermida-López, Marcelino; Moragues-Femenía, Sandra; Pozo-Massó, Miquel; Casals-Farran, Joan

    2017-03-01

    To evaluate the spatial accuracy of a frameless cone-beam computed tomography (CBCT)-guided cranial radiosurgery (SRS) using an end-to-end (E2E) phantom test methodology. Five clinical SRS plans were mapped to an acrylic phantom containing a radiochromic film. The resulting phantom-based plans (E2E plans) were delivered four times. The phantom was setup on the treatment table with intentional misalignments, and CBCT-imaging was used to align it prior to E2E plan delivery. Comparisons (global gamma analysis) of the planned and delivered dose to the film were performed using a commercial triple-channel film dosimetry software. The necessary distance-to-agreement to achieve a 95% (DTA95) gamma passing rate for a fixed 3% dose difference provided an estimate of the spatial accuracy of CBCT-guided SRS. Systematic (∑) and random (σ) error components, as well as 95% confidence levels were derived for the DTA95 metric. The overall systematic spatial accuracy averaged over all tests was 1.4mm (SD: 0.2mm), with a corresponding 95% confidence level of 1.8mm. The systematic (Σ) and random (σ) spatial components of the accuracy derived from the E2E tests were 0.2mm and 0.8mm, respectively. The E2E methodology used in this study allowed an estimation of the spatial accuracy of our CBCT-guided SRS procedure. Subsequently, a PTV margin of 2.0mm is currently used in our department. Copyright © 2017 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  15. Three-Dimensional Accuracy of Facial Scan for Facial Deformities in Clinics: A New Evaluation Method for Facial Scanner Accuracy.

    PubMed

    Zhao, Yi-Jiao; Xiong, Yu-Xue; Wang, Yong

    2017-01-01

    In this study, the practical accuracy (PA) of optical facial scanners for facial deformity patients in oral clinic was evaluated. Ten patients with a variety of facial deformities from oral clinical were included in the study. For each patient, a three-dimensional (3D) face model was acquired, via a high-accuracy industrial "line-laser" scanner (Faro), as the reference model and two test models were obtained, via a "stereophotography" (3dMD) and a "structured light" facial scanner (FaceScan) separately. Registration based on the iterative closest point (ICP) algorithm was executed to overlap the test models to reference models, and "3D error" as a new measurement indicator calculated by reverse engineering software (Geomagic Studio) was used to evaluate the 3D global and partial (upper, middle, and lower parts of face) PA of each facial scanner. The respective 3D accuracy of stereophotography and structured light facial scanners obtained for facial deformities was 0.58±0.11 mm and 0.57±0.07 mm. The 3D accuracy of different facial partitions was inconsistent; the middle face had the best performance. Although the PA of two facial scanners was lower than their nominal accuracy (NA), they all met the requirement for oral clinic use.

  16. Systematic Review and Meta-Analysis of Studies Evaluating Diagnostic Test Accuracy: A Practical Review for Clinical Researchers-Part II. Statistical Methods of Meta-Analysis

    PubMed Central

    Lee, Juneyoung; Kim, Kyung Won; Choi, Sang Hyun; Huh, Jimi

    2015-01-01

    Meta-analysis of diagnostic test accuracy studies differs from the usual meta-analysis of therapeutic/interventional studies in that, it is required to simultaneously analyze a pair of two outcome measures such as sensitivity and specificity, instead of a single outcome. Since sensitivity and specificity are generally inversely correlated and could be affected by a threshold effect, more sophisticated statistical methods are required for the meta-analysis of diagnostic test accuracy. Hierarchical models including the bivariate model and the hierarchical summary receiver operating characteristic model are increasingly being accepted as standard methods for meta-analysis of diagnostic test accuracy studies. We provide a conceptual review of statistical methods currently used and recommended for meta-analysis of diagnostic test accuracy studies. This article could serve as a methodological reference for those who perform systematic review and meta-analysis of diagnostic test accuracy studies. PMID:26576107

  17. Development of Grammatical Accuracy in English-Speaking Children with Cochlear Implants: A Longitudinal Study

    ERIC Educational Resources Information Center

    Guo, Ling-Yu; Spencer, Linda J.

    2017-01-01

    Purpose: We sought to evaluate the development of grammatical accuracy in English-speaking children with cochlear implants (CIs) over a 3-year span. Method: Ten children who received CIs before age 30 months participated in this study at 3, 4, and 5 years postimplantation. For the purpose of comparison, 10 children each at ages 3, 4, and 5 years…

  18. English Verb Accuracy of Bilingual Cantonese-English Preschoolers.

    PubMed

    Rezzonico, Stefano; Goldberg, Ahuva; Milburn, Trelani; Belletti, Adriana; Girolametto, Luigi

    2017-07-26

    Knowledge of verb development in typically developing bilingual preschoolers may inform clinicians about verb accuracy rates during the 1st 2 years of English instruction. This study aimed to investigate tensed verb accuracy in 2 assessment contexts in 4- and 5-year-old Cantonese-English bilingual preschoolers. The sample included 47 Cantonese-English bilinguals enrolled in English preschools. Half of the children were in their 1st 4 months of English language exposure, and half had completed 1 year and 4 months of exposure to English. Data were obtained from the Test of Early Grammatical Impairment (Rice & Wexler, 2001) and from a narrative generated in English. By the 2nd year of formal exposure to English, children in the present study approximated 33% accuracy of tensed verbs in a formal testing context versus 61% in a narrative context. The use of the English verb BE approximated mastery. Predictors of English third-person singular verb accuracy were task, grade, English expressive vocabulary, and lemma frequency. Verb tense accuracy was low across both groups, but a precocious mastery of BE was observed. The results of the present study suggest that speech-language pathologists may consider, in addition to an elicitation task, evaluating the use of verbs during narratives in bilingual Cantonese-English bilingual children.

  19. Value of physical tests in diagnosing cervical radiculopathy: a systematic review.

    PubMed

    Thoomes, Erik J; van Geest, Sarita; van der Windt, Danielle A; Falla, Deborah; Verhagen, Arianne P; Koes, Bart W; Thoomes-de Graaf, Marloes; Kuijper, Barbara; Scholten-Peeters, Wendy G M; Vleggeert-Lankamp, Carmen L

    2018-01-01

    In clinical practice, the diagnosis of cervical radiculopathy is based on information from the patient's history, physical examination, and diagnostic imaging. Various physical tests may be performed, but their diagnostic accuracy is unknown. This study aimed to summarize and update the evidence on diagnostic performance of tests carried out during a physical examination for the diagnosis of cervical radiculopathy. A review of the accuracy of diagnostic tests was carried out. The study sample comprised diagnostic studies comparing results of tests performed during a physical examination in diagnosing cervical radiculopathy with a reference standard of imaging or surgical findings. Sensitivity, specificity, likelihood ratios are presented, together with pooled results for sensitivity and specificity. A literature search up to March 2016 was performed in CENTRAL, PubMed (MEDLINE), Embase, CINAHL, Web of Science, and Google Scholar. The methodological quality of studies was assessed using the QUADAS-2. Five diagnostic accuracy studies were identified. Only Spurling's test was evaluated in more than one study, showing high specificity ranging from 0.89 to 1.00 (95% confidence interval [CI]: 0.59-1.00); sensitivity varied from 0.38 to 0.97 (95% CI: 0.21-0.99). No studies were found that assessed the diagnostic accuracy of widely used neurological tests such as key muscle strength, tendon reflexes, and sensory impairments. There is limited evidence for accuracy of physical examination tests for the diagnosis of cervical radiculopathy. When consistent with patient history, clinicians may use a combination of Spurling's, axial traction, and an Arm Squeeze test to increase the likelihood of a cervical radiculopathy, whereas a combined results of four negative neurodynamics tests and an Arm Squeeze test could be used to rule out the disorder. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Dissociating Appraisals of Accuracy and Recollection in Autobiographical Remembering

    ERIC Educational Resources Information Center

    Scoboria, Alan; Pascal, Lisa

    2016-01-01

    Recent studies of metamemory appraisals implicated in autobiographical remembering have established distinct roles for judgments of occurrence, recollection, and accuracy for past events. In studies involving everyday remembering, measures of recollection and accuracy correlate highly (>.85). Thus although their measures are structurally…

  1. Influence of Pedometer Position on Pedometer Accuracy at Various Walking Speeds: A Comparative Study

    PubMed Central

    Lovis, Christian

    2016-01-01

    Background Demographic growth in conjunction with the rise of chronic diseases is increasing the pressure on health care systems in most OECD countries. Physical activity is known to be an essential factor in improving or maintaining good health. Walking is especially recommended, as it is an activity that can easily be performed by most people without constraints. Pedometers have been extensively used as an incentive to motivate people to become more active. However, a recognized problem with these devices is their diminishing accuracy associated with decreased walking speed. The arrival on the consumer market of new devices, worn indifferently either at the waist, wrist, or as a necklace, gives rise to new questions regarding their accuracy at these different positions. Objective Our objective was to assess the performance of 4 pedometers (iHealth activity monitor, Withings Pulse O2, Misfit Shine, and Garmin vívofit) and compare their accuracy according to their position worn, and at various walking speeds. Methods We conducted this study in a controlled environment with 21 healthy adults required to walk 100 m at 3 different paces (0.4 m/s, 0.6 m/s, and 0.8 m/s) regulated by means of a string attached between their legs at the level of their ankles and a metronome ticking the cadence. To obtain baseline values, we asked the participants to walk 200 m at their own pace. Results A decrease of accuracy was positively correlated with reduced speed for all pedometers (12% mean error at self-selected pace, 27% mean error at 0.8 m/s, 52% mean error at 0.6 m/s, and 76% mean error at 0.4 m/s). Although the position of the pedometer on the person did not significantly influence its accuracy, some interesting tendencies can be highlighted in 2 settings: (1) positioning the pedometer at the waist at a speed greater than 0.8 m/s or as a necklace at preferred speed tended to produce lower mean errors than at the wrist position; and (2) at a slow speed (0.4 m/s), pedometers

  2. Who Should Mark What? A Study of Factors Affecting Marking Accuracy in a Biology Examination

    ERIC Educational Resources Information Center

    Suto, Irenka; Nadas, Rita; Bell, John

    2011-01-01

    Accurate marking is crucial to the reliability and validity of public examinations, in England and internationally. Factors contributing to accuracy have been conceptualised as affecting either marking task demands or markers' personal expertise. The aim of this empirical study was to develop this conceptualisation through investigating the…

  3. A meta-analysis of use of Prostate Imaging Reporting and Data System Version 2 (PI-RADS V2) with multiparametric MR imaging for the detection of prostate cancer.

    PubMed

    Zhang, Li; Tang, Min; Chen, Sipan; Lei, Xiaoyan; Zhang, Xiaoling; Huan, Yi

    2017-12-01

    This meta-analysis was undertaken to review the diagnostic accuracy of PI-RADS V2 for prostate cancer (PCa) detection with multiparametric MR (mp-MR). A comprehensive literature search of electronic databases was performed by two observers independently. Inclusion criteria were original research using the PI-RADS V2 system in reporting prostate MRI. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Data necessary to complete 2 × 2 contingency tables were obtained from the included studies. Thirteen studies (2,049 patients) were analysed. This is an initial meta-analysis of PI-RADs V2 and the overall diagnostic accuracy in diagnosing PCa was as follows: pooled sensitivity, 0.85 (0.78-0.91); pooled specificity, 0.71 (0.60-0.80); pooled positive likelihood ratio (LR+), 2.92 (2.09-4.09); pooled negative likelihood ratio (LR-), 0.21 (0.14-0.31); pooled diagnostic odds ratio (DOR), 14.08 (7.93-25.01), respectively. Positive predictive values ranged from 0.54 to 0.97 and negative predictive values ranged from 0.26 to 0.92. Currently available evidence indicates that PI-RADS V2 appears to have good diagnostic accuracy in patients with PCa lesions with high sensitivity and moderate specificity. However, no recommendation regarding the best threshold can be provided because of heterogeneity. • PI-RADS V2 shows good diagnostic accuracy for PCa detection. • Initially pooled specificity of PI-RADS v2 remains moderate. • PCa detection is increased by experienced radiologists. • There is currently a high heterogeneity in prostate diagnostics with MRI.

  4. Accuracy of Recalled Body Weight – A Study with 20-years of Follow-up

    PubMed Central

    Dahl, Anna K; Reynolds, Chandra A

    2013-01-01

    Objective Weight changes may be an important indicator of an ongoing pathological process. Retrospective self-report might be the only possibility to capture prior weight. The objective of the study was to evaluate the accuracy of retrospective recall of body weight in old age and factors that might predict accuracy. Design and Methods In 2007, 646 participants (mean age, 71.6 years) of the Swedish Adoption/Twin Study of Aging (SATSA) answered questions about their present weight and how much they weighed 20-years ago. Of these, 436 had self-reported their weight twenty years earlier and among these 134 had also had their weight assessed at this time point. Results Twenty year retrospectively recalled weight underestimated the prior assessed weight by −1.89 ± 5.9 kg and underestimated prior self-reported weight by −0.55 ± 5.2 kg. Moreover, 82.4% of the sample were accurate within 10%, and 45.8% were accurate within 5% of their prior assessed weights; similarly, 84.2% and 58.0 % were accurate within 10% and 5% respectively, for prior self-reported weight. Current higher body mass index and preferences of reporting weights ending with zero or five was associated with an underestimation of prior weight, while greater weight change over 20 year, and low Mini-Mental State Scores (MMSE) (<25) led to an overestimation of prior weight. Conclusions Recalled weight comes close to the assessed population mean, but at the individual level there is a large variation. The accuracy is affected by current BMI, changes in weight, end-digit preferences, and current cognitive ability. Recalled weight should be used with caution. PMID:23913738

  5. Accuracy of digital impressions of multiple dental implants: an in vitro study.

    PubMed

    Vandeweghe, Stefan; Vervack, Valentin; Dierens, Melissa; De Bruyn, Hugo

    2017-06-01

    Studies demonstrated that the accuracy of intra-oral scanners can be compared with conventional impressions for most indications. However, little is known about their applicability to take impressions of multiple implants. The aim of this study was to evaluate the accuracy of four intra-oral scanners when applied for implant impressions in the edentulous jaw. An acrylic mandibular cast containing six external connection implants (region 36, 34, 32, 42, 44 and 46) with PEEK scanbodies was scanned using four intra-oral scanners: the Lava C.O.S. and the 3M True Definition, Cerec Omnicam and 3Shape Trios. Each model was scanned 10 times with every intra-oral scanner. As a reference, a highly accurate laboratory scanner (104i, Imetric, Courgenay, Switzerland) was used. The scans were imported into metrology software (Geomagic Qualify 12) for analyses. Accuracy was measured in terms of trueness (comparing test and reference) and precision (determining the deviation between different test scans). Mann-Whitney U-test and Wilcoxon signed rank test were used to detect statistically significant differences in trueness and precision respectively. The mean trueness was 0.112 mm for Lava COS, 0.035 mm for 3M TrueDef, 0.028 mm for Trios and 0.061 mm for Cerec Omnicam. There was no statistically significant difference between 3M TrueDef and Trios (P = 0.262). Cerec Omnicam was less accurate than 3M TrueDef (P = 0.013) and Trios (P = 0.005), but more accurate compared to Lava COS (P = 0.007). Lava COS was also less accurate compared to 3M TrueDef (P = 0.005) and Trios (P = 0.005). The mean precision was 0.066 mm for Lava COS, 0.030 mm for 3M TrueDef, 0.033 mm for Trios and 0.059 mm for Cerec Omnicam. There was no statistically significant difference between 3M TrueDef and Trios (P = 0.119). Cerec Omnicam was less accurate compared to 3M TrueDef (P < 0.001) and Trios (P < 0.001), but no difference was found with Lava COS (P = 0.169). Lava COS was also

  6. Response Latency as a Predictor of the Accuracy of Children's Reports

    ERIC Educational Resources Information Center

    Ackerman, Rakefet; Koriat, Asher

    2011-01-01

    Researchers have explored various diagnostic cues to the accuracy of information provided by child eyewitnesses. Previous studies indicated that children's confidence in their reports predicts the relative accuracy of these reports, and that the confidence-accuracy relationship generally improves as children grow older. In this study, we examined…

  7. Genome-wide association study and accuracy of genomic prediction for teat number in Duroc pigs using genotyping-by-sequencing.

    PubMed

    Tan, Cheng; Wu, Zhenfang; Ren, Jiangli; Huang, Zhuolin; Liu, Dewu; He, Xiaoyan; Prakapenka, Dzianis; Zhang, Ran; Li, Ning; Da, Yang; Hu, Xiaoxiang

    2017-03-29

    The number of teats in pigs is related to a sow's ability to rear piglets to weaning age. Several studies have identified genes and genomic regions that affect teat number in swine but few common results were reported. The objective of this study was to identify genetic factors that affect teat number in pigs, evaluate the accuracy of genomic prediction, and evaluate the contribution of significant genes and genomic regions to genomic broad-sense heritability and prediction accuracy using 41,108 autosomal single nucleotide polymorphisms (SNPs) from genotyping-by-sequencing on 2936 Duroc boars. Narrow-sense heritability and dominance heritability of teat number estimated by genomic restricted maximum likelihood were 0.365 ± 0.030 and 0.035 ± 0.019, respectively. The accuracy of genomic predictions, calculated as the average correlation between the genomic best linear unbiased prediction and phenotype in a tenfold validation study, was 0.437 ± 0.064 for the model with additive and dominance effects and 0.435 ± 0.064 for the model with additive effects only. Genome-wide association studies (GWAS) using three methods of analysis identified 85 significant SNP effects for teat number on chromosomes 1, 6, 7, 10, 11, 12 and 14. The region between 102.9 and 106.0 Mb on chromosome 7, which was reported in several studies, had the most significant SNP effects in or near the PTGR2, FAM161B, LIN52, VRTN, FCF1, AREL1 and LRRC74A genes. This region accounted for 10.0% of the genomic additive heritability and 8.0% of the accuracy of prediction. The second most significant chromosome region not reported by previous GWAS was the region between 77.7 and 79.7 Mb on chromosome 11, where SNPs in the FGF14 gene had the most significant effect and accounted for 5.1% of the genomic additive heritability and 5.2% of the accuracy of prediction. The 85 significant SNPs accounted for 28.5 to 28.8% of the genomic additive heritability and 35.8 to 36.8% of the accuracy of

  8. Continuous electroencephalography predicts delayed cerebral ischemia after subarachnoid hemorrhage: A prospective study of diagnostic accuracy.

    PubMed

    Rosenthal, Eric S; Biswal, Siddharth; Zafar, Sahar F; O'Connor, Kathryn L; Bechek, Sophia; Shenoy, Apeksha V; Boyle, Emily J; Shafi, Mouhsin M; Gilmore, Emily J; Foreman, Brandon P; Gaspard, Nicolas; Leslie-Mazwi, Thabele M; Rosand, Jonathan; Hoch, Daniel B; Ayata, Cenk; Cash, Sydney S; Cole, Andrew J; Patel, Aman B; Westover, M Brandon

    2018-04-16

    Delayed cerebral ischemia (DCI) is a common, disabling complication of subarachnoid hemorrhage (SAH). Preventing DCI is a key focus of neurocritical care, but interventions carry risk and cannot be applied indiscriminately. Although retrospective studies have identified continuous electroencephalographic (cEEG) measures associated with DCI, no study has characterized the accuracy of cEEG with sufficient rigor to justify using it to triage patients to interventions or clinical trials. We therefore prospectively assessed the accuracy of cEEG for predicting DCI, following the Standards for Reporting Diagnostic Accuracy Studies. We prospectively performed cEEG in nontraumatic, high-grade SAH patients at a single institution. The index test consisted of clinical neurophysiologists prospectively reporting prespecified EEG alarms: (1) decreasing relative alpha variability, (2) decreasing alpha-delta ratio, (3) worsening focal slowing, or (4) late appearing epileptiform abnormalities. The diagnostic reference standard was DCI determined by blinded, adjudicated review. Primary outcome measures were sensitivity and specificity of cEEG for subsequent DCI, determined by multistate survival analysis, adjusted for baseline risk. One hundred three of 227 consecutive patients were eligible and underwent cEEG monitoring (7.7-day mean duration). EEG alarms occurred in 96.2% of patients with and 19.6% without subsequent DCI (1.9-day median latency, interquartile range = 0.9-4.1). Among alarm subtypes, late onset epileptiform abnormalities had the highest predictive value. Prespecified EEG findings predicted DCI among patients with low (91% sensitivity, 83% specificity) and high (95% sensitivity, 77% specificity) baseline risk. cEEG accurately predicts DCI following SAH and may help target therapies to patients at highest risk of secondary brain injury. Ann Neurol 2018. © 2018 American Neurological Association.

  9. Improving coding accuracy in an academic practice.

    PubMed

    Nguyen, Dana; O'Mara, Heather; Powell, Robert

    2017-01-01

    Practice management has become an increasingly important component of graduate medical education. This applies to every practice environment; private, academic, and military. One of the most critical aspects of practice management is documentation and coding for physician services, as they directly affect the financial success of any practice. Our quality improvement project aimed to implement a new and innovative method for teaching billing and coding in a longitudinal fashion in a family medicine residency. We hypothesized that implementation of a new teaching strategy would increase coding accuracy rates among residents and faculty. Design: single group, pretest-posttest. military family medicine residency clinic. Study populations: 7 faculty physicians and 18 resident physicians participated as learners in the project. Educational intervention: monthly structured coding learning sessions in the academic curriculum that involved learner-presented cases, small group case review, and large group discussion. overall coding accuracy (compliance) percentage and coding accuracy per year group for the subjects that were able to participate longitudinally. Statistical tests used: average coding accuracy for population; paired t test to assess improvement between 2 intervention periods, both aggregate and by year group. Overall coding accuracy rates remained stable over the course of time regardless of the modality of the educational intervention. A paired t test was conducted to compare coding accuracy rates at baseline (mean (M)=26.4%, SD=10%) to accuracy rates after all educational interventions were complete (M=26.8%, SD=12%); t24=-0.127, P=.90. Didactic teaching and small group discussion sessions did not improve overall coding accuracy in a residency practice. Future interventions could focus on educating providers at the individual level.

  10. A literature review of anthropometric studies of school students for ergonomics purposes: Are accuracy, precision and reliability being considered?

    PubMed

    Bravo, G; Bragança, S; Arezes, P M; Molenbroek, J F M; Castellucci, H I

    2018-05-22

    Despite offering many benefits, direct manual anthropometric measurement method can be problematic due to their vulnerability to measurement errors. The purpose of this literature review was to determine, whether or not the currently published anthropometric studies of school children, related to ergonomics, mentioned or evaluated the variables precision, reliability or accuracy in the direct manual measurement method. Two bibliographic databases, and the bibliographic references of all the selected papers were used for finding relevant published papers in the fields considered in this study. Forty-six (46) studies met the criteria previously defined for this literature review. However, only ten (10) studies mentioned at least one of the analyzed variables, and none has evaluated all of them. Only reliability was assessed by three papers. Moreover, in what regards the factors that affect precision, reliability and accuracy, the reviewed papers presented large differences. This was particularly clear in the instruments used for the measurements, which were not consistent throughout the studies. Additionally, it was also clear that there was a lack of information regarding the evaluators' training and procedures for anthropometric data collection, which are assumed to be the most important issues that affect precision, reliability and accuracy. Based on the review of the literature, it was possible to conclude that the considered anthropometric studies had not focused their attention to the analysis of precision, reliability and accuracy of the manual measurement methods. Hence, and with the aim of avoiding measurement errors and misleading data, anthropometric studies should put more efforts and care on testing measurement error and defining the procedures used to collect anthropometric data.

  11. Discrimination in measures of knowledge monitoring accuracy

    PubMed Central

    Was, Christopher A.

    2014-01-01

    Knowledge monitoring predicts academic outcomes in many contexts. However, measures of knowledge monitoring accuracy are often incomplete. In the current study, a measure of students’ ability to discriminate known from unknown information as a component of knowledge monitoring was considered. Undergraduate students’ knowledge monitoring accuracy was assessed and used to predict final exam scores in a specific course. It was found that gamma, a measure commonly used as the measure of knowledge monitoring accuracy, accounted for a small, but significant amount of variance in academic performance whereas the discrimination and bias indexes combined to account for a greater amount of variance in academic performance. PMID:25339979

  12. Between simplicity and accuracy: Effect of adding modeling details on quarter vehicle model accuracy.

    PubMed

    Soong, Ming Foong; Ramli, Rahizar; Saifizul, Ahmad

    2017-01-01

    Quarter vehicle model is the simplest representation of a vehicle that belongs to lumped-mass vehicle models. It is widely used in vehicle and suspension analyses, particularly those related to ride dynamics. However, as much as its common adoption, it is also commonly accepted without quantification that this model is not as accurate as many higher-degree-of-freedom models due to its simplicity and limited degrees of freedom. This study investigates the trade-off between simplicity and accuracy within the context of quarter vehicle model by determining the effect of adding various modeling details on model accuracy. In the study, road input detail, tire detail, suspension stiffness detail and suspension damping detail were factored in, and several enhanced models were compared to the base model to assess the significance of these details. The results clearly indicated that these details do have effect on simulated vehicle response, but to various extents. In particular, road input detail and suspension damping detail have the most significance and are worth being added to quarter vehicle model, as the inclusion of these details changed the response quite fundamentally. Overall, when it comes to lumped-mass vehicle modeling, it is reasonable to say that model accuracy depends not just on the number of degrees of freedom employed, but also on the contributions from various modeling details.

  13. Between simplicity and accuracy: Effect of adding modeling details on quarter vehicle model accuracy

    PubMed Central

    2017-01-01

    Quarter vehicle model is the simplest representation of a vehicle that belongs to lumped-mass vehicle models. It is widely used in vehicle and suspension analyses, particularly those related to ride dynamics. However, as much as its common adoption, it is also commonly accepted without quantification that this model is not as accurate as many higher-degree-of-freedom models due to its simplicity and limited degrees of freedom. This study investigates the trade-off between simplicity and accuracy within the context of quarter vehicle model by determining the effect of adding various modeling details on model accuracy. In the study, road input detail, tire detail, suspension stiffness detail and suspension damping detail were factored in, and several enhanced models were compared to the base model to assess the significance of these details. The results clearly indicated that these details do have effect on simulated vehicle response, but to various extents. In particular, road input detail and suspension damping detail have the most significance and are worth being added to quarter vehicle model, as the inclusion of these details changed the response quite fundamentally. Overall, when it comes to lumped-mass vehicle modeling, it is reasonable to say that model accuracy depends not just on the number of degrees of freedom employed, but also on the contributions from various modeling details. PMID:28617819

  14. Understanding the delayed-keyword effect on metacomprehension accuracy.

    PubMed

    Thiede, Keith W; Dunlosky, John; Griffin, Thomas D; Wiley, Jennifer

    2005-11-01

    The typical finding from research on metacomprehension is that accuracy is quite low. However, recent studies have shown robust accuracy improvements when judgments follow certain generation tasks (summarizing or keyword listing) but only when these tasks are performed at a delay rather than immediately after reading (K. W. Thiede & M. C. M. Anderson, 2003; K. W. Thiede, M. C. M. Anderson, & D. Therriault, 2003). The delayed and immediate conditions in these studies confounded the delay between reading and generation tasks with other task lags, including the lag between multiple generation tasks and the lag between generation tasks and judgments. The first 2 experiments disentangle these confounded manipulations and provide clear evidence that the delay between reading and keyword generation is the only lag critical to improving metacomprehension accuracy. The 3rd and 4th experiments show that not all delayed tasks produce improvements and suggest that delayed generative tasks provide necessary diagnostic cues about comprehension for improving metacomprehension accuracy.

  15. The Influence of Motor Skills on Measurement Accuracy

    NASA Astrophysics Data System (ADS)

    Brychta, Petr; Sadílek, Marek; Brychta, Josef

    2016-10-01

    This innovative study trying to do interdisciplinary interface at first view different ways fields: kinantropology and mechanical engineering. A motor skill is described as an action which involves the movement of muscles in a body. Gross motor skills permit functions as a running, jumping, walking, punching, lifting and throwing a ball, maintaining a body balance, coordinating etc. Fine motor skills captures smaller neuromuscular actions, such as holding an object between the thumb and a finger. In mechanical inspection, the accuracy of measurement is most important aspect. The accuracy of measurement to some extent is also dependent upon the sense of sight or sense of touch associated with fine motor skills. It is therefore clear that the level of motor skills will affect the precision and accuracy of measurement in metrology. Aim of this study is literature review to find out fine motor skills level of individuals and determine the potential effect of different fine motor skill performance on precision and accuracy of mechanical engineering measuring.

  16. Towards improving diagnosis of memory loss in general practice: TIMeLi diagnostic test accuracy study protocol.

    PubMed

    Creavin, Sam T; Cullum, Sarah J; Haworth, Judy; Wye, Lesley; Bayer, Antony; Fish, Mark; Purdy, Sarah; Ben-Shlomo, Yoav

    2016-07-19

    People with cognitive problems, and their families, report distress and uncertainty whilst undergoing evaluation for dementia and perceive that traditional diagnostic evaluation in secondary care is insufficiently patient centred. The James Lind Alliance has prioritised research to investigate the role of primary care in supporting a more effective diagnostic pathway, and the topic is also of interest to health commissioners. However, there are very few studies that investigate the accuracy of diagnostic tests for dementia in primary care. We will conduct a prospective diagnostic test accuracy study to evaluate the accuracy of a range of simple tests for diagnosing all-cause-dementia in symptomatic people aged over 70 years who have consulted with their general practitioner (GP). We will invite eligible people to attend a research clinic where they will undergo a range of index tests that a GP could perform in the surgery and also be assessed by a specialist in memory disorders at the same appointment. Participating GPs will request neuroimaging and blood tests and otherwise manage patients in line with their usual clinical practice. The reference standard will be the consensus judgement of three experts (neurologist, psychiatrist and geriatrician) based on information from the specialist assessment, GP records and investigations, but not including items in the index test battery. The target condition will be all-cause dementia but we will also investigate diagnostic accuracy for sub-types where possible. We will use qualitative interviews with patients and focus groups with clinicians to help us understand the acceptability and feasibility of diagnosing dementia in primary care using the tests that we are investigating. Our results will help clinicians decide on which tests to perform in someone where there is concern about possible dementia and inform commissioning of diagnostic pathways.

  17. Is there sufficient evidence for tuning fork tests in diagnosing fractures? A systematic review.

    PubMed

    Mugunthan, Kayalvili; Doust, Jenny; Kurz, Bodo; Glasziou, Paul

    2014-08-04

    To determine the diagnostic accuracy of tuning fork tests for detecting fractures. Systematic review of primary studies evaluating the diagnostic accuracy of tuning fork tests for the presence of fracture. We searched MEDLINE, CINAHL, AMED, EMBASE, Sports Discus, CAB Abstracts and Web of Science from commencement to November 2012. We manually searched the reference lists of any review papers and any identified relevant studies. Two reviewers independently reviewed the list of potentially eligible studies and rated the studies for quality using the QUADAS-2 tool. Data were extracted to form 2×2 contingency tables. The primary outcome measure was the accuracy of the test as measured by its sensitivity and specificity with 95% CIs. We included six studies (329 patients), with two types of tuning fork tests (pain induction and loss of sound transmission). The studies included patients with an age range 7-60 years. The prevalence of fracture ranged from 10% to 80%. The sensitivity of the tuning fork tests was high, ranging from 75% to 100%. The specificity of the tests was highly heterogeneous, ranging from 18% to 95%. Based on the studies in this review, tuning fork tests have some value in ruling out fractures, but are not sufficiently reliable or accurate for widespread clinical use. The small sample size of the studies and the observed heterogeneity make generalisable conclusion difficult. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  18. [Study on accuracy of endoscopic polyp size measurement by disposable graduated biopsy forceps].

    PubMed

    Liu, Ping; Zhang, Xiu; Lin, Hui-ping; Jin, Hei-jing; Leng, Qiang; Zhang, Jin-hao; Zhang, Yang; Yao, Hang; Wu, Kun-lan

    2013-12-01

    To study the accuracy of endoscopic polyp size measurement by disposable graduated biopsy forceps (DGBF). Accurate gradation of 1 mm was made in the wire of disposable graduated biopsy forceps, which was used to measure the size of tumors under endoscopy. Fifty-eight polyps from 43 patients underwent endoscopy in our department from May to June 2013 were enrolled. Size of polyp was measured and compared among DGBF, routine estimation and direct measurement after resection. The accuracy of polyp size measurement was investigated by four colonoscopists who had finished at least 2000 procedures of colonoscopy. The mean diameter of post-polypectomy measurement was (1.02±0.84) cm. Diameter was less than 1 cm in 36 polyps, 1 to 2 cm in 15, and over 2 cm in 7. The mean diameter of visual estimation was (1.29±1.07) cm, and the difference was significant as compared with actual size (P=0.000). The mean diameter measured by DGBF was (1.02±0.82) cm, and the difference was not significant as compared with actual size (P=0.775). The ratio of visual estimation to actual size was 1.29±0.31, and DGBF estimation to actual size was 1.02±0.11 with significant difference (P=0.000). The accurate rate of DGBF in estimating polyp size was 77.6% (45/58), which was obviously higher as compared to visual estimation [19.0% (11/58), P=0.000]. The accuracy of DGBF as a scale in the estimation of poly size increases as compared to visual estimation.

  19. Is there any evidence for the validity of diagnostic criteria used for accommodative and nonstrabismic binocular dysfunctions?

    PubMed

    Cacho-Martínez, Pilar; García-Muñoz, Ángel; Ruiz-Cantero, María Teresa

    2014-01-01

    To analyze the diagnostic criteria used in the scientific literature published in the past 25 years for accommodative and nonstrabismic binocular dysfunctions and to explore if the epidemiological analysis of diagnostic validity has been used to propose which clinical criteria should be used for diagnostic purposes. We carried out a systematic review of papers on accommodative and non-strabic binocular disorders published from 1986 to 2012 analysing the MEDLINE, CINAHL, PsycINFO and FRANCIS databases. We admitted original articles about diagnosis of these anomalies in any population. We identified 839 articles and 12 studies were included. The quality of included articles was assessed using the QUADAS-2 tool. The review shows a wide range of clinical signs and cut-off points between authors. Only 3 studies (regarding accommodative anomalies) assessed diagnostic accuracy of clinical signs. Their results suggest using the accommodative amplitude and monocular accommodative facility for diagnosing accommodative insufficiency and a high positive relative accommodation for accommodative excess. The remaining 9 articles did not analyze diagnostic accuracy, assessing a diagnosis with the criteria the authors considered. We also found differences between studies in the way of considering patients' symptomatology. 3 studies of 12 analyzed, performed a validation of a symptom survey used for convergence insufficiency. Scientific literature reveals differences between authors according to diagnostic criteria for accommodative and nonstrabismic binocular dysfunctions. Diagnostic accuracy studies show that there is only certain evidence for accommodative conditions. For binocular anomalies there is only evidence about a validated questionnaire for convergence insufficiency with no data of diagnostic accuracy. Copyright © 2012 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  20. A Study of the Accuracy and Reliability of Articles about Alopecia in Newspapers.

    PubMed

    Kim, Hyojin; Park, In Ho; Kim, Do Hyeong; Park, So Hee; Cho, Gyeong Je; Seol, Jung Eun

    2018-06-01

    There is growing interest in alopecia among the general population. Many people obtain information from easily accessible media rather than from doctors; thus, the media can play an important role in shaping public opinion. The goal of this study was to evaluate the content and reliability of newspaper articles on alopecia. Newspapers were categorized into three groups: one group of print newspapers and two groups of online newspapers. Online newspapers were further divided into two groups according to type of publishing company; one publishes both print and online newspapers and the other publishes online newspapers only. The most frequently subscribed or circulated newspaper in each group was selected. Articles containing information on alopecia were selected from 3 years of each newspaper and evaluated for reliability. Most articles in each group used the general term "alopecia" instead of naming a specific hair loss disease. The majority of articles were based on consultation with experts. Assessment of the accuracy of articles with three grade scales showed that the percentage with high accuracy was 38.9%, 47.2%, and 23.3%. Assessment of reliability scores for five selected articles in each group showed that there were statistically significant differences between common readers and dermatologists ( p <0.05). The results of this study suggest that closer monitoring of the media is required to supply easily accessible, balanced, and trustworthy information regarding alopecia.

  1. Pitch discrimination accuracy in musicians vs nonmusicians: an event-related potential and behavioral study.

    PubMed

    Tervaniemi, Mari; Just, Viola; Koelsch, Stefan; Widmann, Andreas; Schröger, Erich

    2005-02-01

    Previously, professional violin players were found to automatically discriminate tiny pitch changes, not discriminable by nonmusicians. The present study addressed the pitch processing accuracy in musicians with expertise in playing a wide selection of instruments (e.g., piano; wind and string instruments). Of specific interest was whether also musicians with such divergent backgrounds have facilitated accuracy in automatic and/or attentive levels of auditory processing. Thirteen professional musicians and 13 nonmusicians were presented with frequent standard sounds and rare deviant sounds (0.8, 2, or 4% higher in frequency). Auditory event-related potentials evoked by these sounds were recorded while first the subjects read a self-chosen book and second they indicated behaviorally the detection of sounds with deviant frequency. Musicians detected the pitch changes faster and more accurately than nonmusicians. The N2b and P3 responses recorded during attentive listening had larger amplitude in musicians than in nonmusicians. Interestingly, the superiority in pitch discrimination accuracy in musicians over nonmusicians was observed not only with the 0.8% but also with the 2% frequency changes. Moreover, also nonmusicians detected quite reliably the smallest pitch changes of 0.8%. However, the mismatch negativity (MMN) and P3a recorded during a reading condition did not differentiate musicians and nonmusicians. These results suggest that musical expertise may exert its effects merely at attentive levels of processing and not necessarily already at the preattentive levels.

  2. Haptic perception accuracy depending on self-produced movement.

    PubMed

    Park, Chulwook; Kim, Seonjin

    2014-01-01

    This study measured whether self-produced movement influences haptic perception ability (experiment 1) as well as the factors associated with levels of influence (experiment 2) in racket sports. For experiment 1, the haptic perception accuracy levels of five male table tennis experts and five male novices were examined under two different conditions (no movement vs. movement). For experiment 2, the haptic afferent subsystems of five male table tennis experts and five male novices were investigated in only the self-produced movement-coupled condition. Inferential statistics (ANOVA, t-test) and custom-made devices (shock & vibration sensor, Qualisys Track Manager) of the data were used to determine the haptic perception accuracy (experiment 1, experiment 2) and its association with expertise. The results of this research show that expert-level players acquire higher accuracy with less variability (racket vibration and angle) than novice-level players, especially in their self-produced movement coupled performances. The important finding from this result is that, in terms of accuracy, the skill-associated differences were enlarged during self-produced movement. To explain the origin of this difference between experts and novices, the functional variability of haptic afferent subsystems can serve as a reference. These two factors (self-produced accuracy and the variability of haptic features) as investigated in this study would be useful criteria for educators in racket sports and suggest a broader hypothesis for further research into the effects of the haptic accuracy related to variability.

  3. Combining cow and bull reference populations to increase accuracy of genomic prediction and genome-wide association studies.

    PubMed

    Calus, M P L; de Haas, Y; Veerkamp, R F

    2013-10-01

    Genomic selection holds the promise to be particularly beneficial for traits that are difficult or expensive to measure, such that access to phenotypes on large daughter groups of bulls is limited. Instead, cow reference populations can be generated, potentially supplemented with existing information from the same or (highly) correlated traits available on bull reference populations. The objective of this study, therefore, was to develop a model to perform genomic predictions and genome-wide association studies based on a combined cow and bull reference data set, with the accuracy of the phenotypes differing between the cow and bull genomic selection reference populations. The developed bivariate Bayesian stochastic search variable selection model allowed for an unbalanced design by imputing residuals in the residual updating scheme for all missing records. The performance of this model is demonstrated on a real data example, where the analyzed trait, being milk fat or protein yield, was either measured only on a cow or a bull reference population, or recorded on both. Our results were that the developed bivariate Bayesian stochastic search variable selection model was able to analyze 2 traits, even though animals had measurements on only 1 of 2 traits. The Bayesian stochastic search variable selection model yielded consistently higher accuracy for fat yield compared with a model without variable selection, both for the univariate and bivariate analyses, whereas the accuracy of both models was very similar for protein yield. The bivariate model identified several additional quantitative trait loci peaks compared with the single-trait models on either trait. In addition, the bivariate models showed a marginal increase in accuracy of genomic predictions for the cow traits (0.01-0.05), although a greater increase in accuracy is expected as the size of the bull population increases. Our results emphasize that the chosen value of priors in Bayesian genomic prediction

  4. Recommended reporting standards for test accuracy studies of infectious diseases of finfish, amphibians, molluscs and crustaceans: the STRADAS-aquatic checklist.

    PubMed

    Gardner, Ian A; Whittington, Richard J; Caraguel, Charles G B; Hick, Paul; Moody, Nicholas J G; Corbeil, Serge; Garver, Kyle A; Warg, Janet V; Arzul, Isabelle; Purcell, Maureen K; Crane, Mark St J; Waltzek, Thomas B; Olesen, Niels J; Gallardo Lagno, Alicia

    2016-02-25

    Complete and transparent reporting of key elements of diagnostic accuracy studies for infectious diseases in cultured and wild aquatic animals benefits end-users of these tests, enabling the rational design of surveillance programs, the assessment of test results from clinical cases and comparisons of diagnostic test performance. Based on deficiencies in the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines identified in a prior finfish study (Gardner et al. 2014), we adapted the Standards for Reporting of Animal Diagnostic Accuracy Studies-paratuberculosis (STRADAS-paraTB) checklist of 25 reporting items to increase their relevance to finfish, amphibians, molluscs, and crustaceans and provided examples and explanations for each item. The checklist, known as STRADAS-aquatic, was developed and refined by an expert group of 14 transdisciplinary scientists with experience in test evaluation studies using field and experimental samples, in operation of reference laboratories for aquatic animal pathogens, and in development of international aquatic animal health policy. The main changes to the STRADAS-paraTB checklist were to nomenclature related to the species, the addition of guidelines for experimental challenge studies, and the designation of some items as relevant only to experimental studies and ante-mortem tests. We believe that adoption of these guidelines will improve reporting of primary studies of test accuracy for aquatic animal diseases and facilitate assessment of their fitness-for-purpose. Given the importance of diagnostic tests to underpin the Sanitary and Phytosanitary agreement of the World Trade Organization, the principles outlined in this paper should be applied to other World Organisation for Animal Health (OIE)-relevant species.

  5. A Meta-Analysis of Typhoid Diagnostic Accuracy Studies: A Recommendation to Adopt a Standardized Composite Reference

    PubMed Central

    Storey, Helen L.; Huang, Ying; Crudder, Chris; Golden, Allison; de los Santos, Tala; Hawkins, Kenneth

    2015-01-01

    Novel typhoid diagnostics currently under development have the potential to improve clinical care, surveillance, and the disease burden estimates that support vaccine introduction. Blood culture is most often used as the reference method to evaluate the accuracy of new typhoid tests; however, it is recognized to be an imperfect gold standard. If no single gold standard test exists, use of a composite reference standard (CRS) can improve estimation of diagnostic accuracy. Numerous studies have used a CRS to evaluate new typhoid diagnostics; however, there is no consensus on an appropriate CRS. In order to evaluate existing tests for use as a reference test or inclusion in a CRS, we performed a systematic review of the typhoid literature to include all index/reference test combinations observed. We described the landscape of comparisons performed, showed results of a meta-analysis on the accuracy of the more common combinations, and evaluated sources of variability based on study quality. This wide-ranging meta-analysis suggests that no single test has sufficiently good performance but some existing diagnostics may be useful as part of a CRS. Additionally, based on findings from the meta-analysis and a constructed numerical example demonstrating the use of CRS, we proposed necessary criteria and potential components of a typhoid CRS to guide future recommendations. Agreement and adoption by all investigators of a standardized CRS is requisite, and would improve comparison of new diagnostics across independent studies, leading to the identification of a better reference test and improved confidence in prevalence estimates. PMID:26566275

  6. Trait Perception Accuracy and Acquaintance Within Groups: Tracking Accuracy Development.

    PubMed

    Brown, Jill A; Bernieri, Frank

    2017-05-01

    Previous work on trait perception has evaluated accuracy at discrete stages of relationships (e.g., strangers, best friends). A relatively limited body of literature has investigated changes in accuracy as acquaintance within a dyad or group increases. Small groups of initially unacquainted individuals spent more than 30 hr participating in a wide range of activities designed to represent common interpersonal contexts (e.g., eating, traveling). We calculated how accurately each participant judged others in their group on the big five traits across three distinct points within the acquaintance process: zero acquaintance, after a getting-to-know-you conversation, and after 10 weeks of interaction and activity. Judgments of all five traits exhibited accuracy above chance levels after 10 weeks. An examination of the trait rating stability revealed that much of the revision in judgments occurred not over the course of the 10-week relationship as suspected, but between zero acquaintance and the getting-to-know-you conversation.

  7. Empathic Embarrassment Accuracy in Autism Spectrum Disorder.

    PubMed

    Adler, Noga; Dvash, Jonathan; Shamay-Tsoory, Simone G

    2015-06-01

    Empathic accuracy refers to the ability of perceivers to accurately share the emotions of protagonists. Using a novel task assessing embarrassment, the current study sought to compare levels of empathic embarrassment accuracy among individuals with autism spectrum disorders (ASD) with those of matched controls. To assess empathic embarrassment accuracy, we compared the level of embarrassment experienced by protagonists to the embarrassment felt by participants while watching the protagonists. The results show that while the embarrassment ratings of participants and protagonists were highly matched among controls, individuals with ASD failed to exhibit this matching effect. Furthermore, individuals with ASD rated their embarrassment higher than controls when viewing themselves and protagonists on film, but not while performing the task itself. These findings suggest that individuals with ASD tend to have higher ratings of empathic embarrassment, perhaps due to difficulties in emotion regulation that may account for their impaired empathic accuracy and aberrant social behavior. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.

  8. Effect of provider volume on the accuracy of hospital report cards: a Monte Carlo study.

    PubMed

    Austin, Peter C; Reeves, Mathew J

    2014-03-01

    Hospital report cards, in which outcomes after the provision of medical or surgical care are compared across healthcare providers, are being published with increasing frequency. However, the accuracy of such comparisons is controversial, especially when case volumes are small. The objective was to determine the relationship between hospital case volume and the accuracy of hospital report cards. Monte Carlo simulations were used to examine the influence of hospital case volume on the accuracy of hospital report cards in a setting in which true hospital performance was known with certainty, and perfect risk-adjustment was feasible. The parameters used to generate the simulated data sets were obtained from empirical analyses of data on patients hospitalized with acute myocardial infarction in Ontario, Canada, in which the overall 30-day mortality rate was 11.1%. We found that provider volume had a strong effect on the accuracy of hospital report cards. However, provider volume had to be >300 before ≥70% of hospitals were correctly classified. Furthermore, hospital volume had to be >1000 before ≥80% of hospitals were correctly classified. Producers and users of hospital report cards need to be aware that, even when perfect risk adjustment is possible, the accuracy of hospital report cards is, at best, modest for small to medium-sized case loads (i.e., 100-300). Hospital report cards displayed high degrees of accuracy only when provider volumes exceeded the typical annual hospital case load for many cardiovascular conditions and procedures.

  9. English Verb Accuracy of Bilingual Cantonese-English Preschoolers

    ERIC Educational Resources Information Center

    Rezzonico, Stefano; Goldberg, Ahuva; Milburn, Trelani; Belletti, Adriana; Girolametto, Luigi

    2017-01-01

    Purpose: Knowledge of verb development in typically developing bilingual preschoolers may inform clinicians about verb accuracy rates during the 1st 2 years of English instruction. This study aimed to investigate tensed verb accuracy in 2 assessment contexts in 4- and 5-year-old Cantonese-English bilingual preschoolers. Method: The sample included…

  10. Compassion meditation enhances empathic accuracy and related neural activity

    PubMed Central

    Mascaro, Jennifer S.; Rilling, James K.; Tenzin Negi, Lobsang; Raison, Charles L.

    2013-01-01

    The ability to accurately infer others’ mental states from facial expressions is important for optimal social functioning and is fundamentally impaired in social cognitive disorders such as autism. While pharmacologic interventions have shown promise for enhancing empathic accuracy, little is known about the effects of behavioral interventions on empathic accuracy and related brain activity. This study employed a randomized, controlled and longitudinal design to investigate the effect of a secularized analytical compassion meditation program, cognitive-based compassion training (CBCT), on empathic accuracy. Twenty-one healthy participants received functional MRI scans while completing an empathic accuracy task, the Reading the Mind in the Eyes Test (RMET), both prior to and after completion of either CBCT or a health discussion control group. Upon completion of the study interventions, participants randomized to CBCT and were significantly more likely than control subjects to have increased scores on the RMET and increased neural activity in the inferior frontal gyrus (IFG) and dorsomedial prefrontal cortex (dmPFC). Moreover, changes in dmPFC and IFG activity from baseline to the post-intervention assessment were associated with changes in empathic accuracy. These findings suggest that CBCT may hold promise as a behavioral intervention for enhancing empathic accuracy and the neurobiology supporting it. PMID:22956676

  11. Accuracy, Sensitivity and Specificity of Fine Needle Aspiration Biopsy for Salivary Gland Tumors: A Retrospective Study from 2006 to 2011

    PubMed

    Silva, William P P; Stramandinoli-Zanicotti, Roberta T; Schussel, Juliana L; Ramos, Gyl H A; Ioshi, Sergio O; Sassi, Laurindo M

    2016-11-01

    Objective: This article concerns evaluation of the sensitivity, specificity and accuracy of FNAB for pre-surgical diagnosis of benign and malignant lesions of major and minor salivary glands of patients treated in the Department of Head and Neck Surgery of Erasto Gartner Hospital. Methods: This retrospective study analyzed medical records from January 2006 to December 2011 from patients with salivary gland lesions who underwent preoperative FNAB and, after surgical excision of the lesion, histopathological examination. Results: The study had a cohort of 130 cases, but 34 cases (26.2%) were considered unsatisfactory regarding cytology analyses. Based on the data, sensitivity was 66.7% (6/9), specificity was 81.6% (71/87), accuracy was 80.2% (77/96), the positive predictive value was 66,7% (6/9) and the negative predictive value was 81.6% (71/87). Conclusion: Despite the high rate of inadequate samples obtained in the FNAB in this study the technique offers high specificity, accuracy and acceptable sensitivity. Creative Commons Attribution License

  12. The Social Accuracy Model of Interpersonal Perception: Assessing Individual Differences in Perceptive and Expressive Accuracy

    ERIC Educational Resources Information Center

    Biesanz, Jeremy C.

    2010-01-01

    The social accuracy model of interpersonal perception (SAM) is a componential model that estimates perceiver and target effects of different components of accuracy across traits simultaneously. For instance, Jane may be generally accurate in her perceptions of others and thus high in "perceptive accuracy"--the extent to which a particular…

  13. Municipal water consumption forecast accuracy

    NASA Astrophysics Data System (ADS)

    Fullerton, Thomas M.; Molina, Angel L.

    2010-06-01

    Municipal water consumption planning is an active area of research because of infrastructure construction and maintenance costs, supply constraints, and water quality assurance. In spite of that, relatively few water forecast accuracy assessments have been completed to date, although some internal documentation may exist as part of the proprietary "grey literature." This study utilizes a data set of previously published municipal consumption forecasts to partially fill that gap in the empirical water economics literature. Previously published municipal water econometric forecasts for three public utilities are examined for predictive accuracy against two random walk benchmarks commonly used in regional analyses. Descriptive metrics used to quantify forecast accuracy include root-mean-square error and Theil inequality statistics. Formal statistical assessments are completed using four-pronged error differential regression F tests. Similar to studies for other metropolitan econometric forecasts in areas with similar demographic and labor market characteristics, model predictive performances for the municipal water aggregates in this effort are mixed for each of the municipalities included in the sample. Given the competitiveness of the benchmarks, analysts should employ care when utilizing econometric forecasts of municipal water consumption for planning purposes, comparing them to recent historical observations and trends to insure reliability. Comparative results using data from other markets, including regions facing differing labor and demographic conditions, would also be helpful.

  14. Speed-Accuracy Response Models: Scoring Rules Based on Response Time and Accuracy

    ERIC Educational Resources Information Center

    Maris, Gunter; van der Maas, Han

    2012-01-01

    Starting from an explicit scoring rule for time limit tasks incorporating both response time and accuracy, and a definite trade-off between speed and accuracy, a response model is derived. Since the scoring rule is interpreted as a sufficient statistic, the model belongs to the exponential family. The various marginal and conditional distributions…

  15. Illusory expectations can affect retrieval-monitoring accuracy.

    PubMed

    McDonough, Ian M; Gallo, David A

    2012-03-01

    The present study investigated how expectations, even when illusory, can affect the accuracy of memory decisions. Participants studied words presented in large or small font for subsequent memory tests. Replicating prior work, judgments of learning indicated that participants expected to remember large words better than small words, even though memory for these words was equivalent on a standard test of recognition memory and subjective judgments. Critically, we also included tests that instructed participants to selectively search memory for either large or small words, thereby allowing different memorial expectations to contribute to performance. On these tests we found reduced false recognition when searching memory for large words relative to small words, such that the size illusion paradoxically affected accuracy measures (d' scores) in the absence of actual memory differences. Additional evidence for the role of illusory expectations was that (a) the accuracy effect was obtained only when participants searched memory for the aspect of the stimuli corresponding to illusory expectations (size instead of color) and (b) the accuracy effect was eliminated on a forced-choice test that prevented the influence of memorial expectations. These findings demonstrate the critical role of memorial expectations in the retrieval-monitoring process. 2012 APA, all rights reserved

  16. Recommended reporting standards for test accuracy studies of infectious diseases of finfish, amphibians, molluscs and crustaceans: the STRADAS-aquatic checklist

    USGS Publications Warehouse

    Gardner, Ian A; Whittington, Richard J; Caraguel, Charles G B; Hick, Paul; Moody, Nicholas J G; Corbeil, Serge; Garver, Kyle A.; Warg, Janet V.; Arzul, Isabelle; Purcell, Maureen; St. J. Crane, Mark; Waltzek, Thomas B.; Olesen, Niels J; Lagno, Alicia Gallardo

    2016-01-01

    Complete and transparent reporting of key elements of diagnostic accuracy studies for infectious diseases in cultured and wild aquatic animals benefits end-users of these tests, enabling the rational design of surveillance programs, the assessment of test results from clinical cases and comparisons of diagnostic test performance. Based on deficiencies in the Standards for Reporting of Diagnostic Accuracy (STARD) guidelines identified in a prior finfish study (Gardner et al. 2014), we adapted the Standards for Reporting of Animal Diagnostic Accuracy Studies—paratuberculosis (STRADAS-paraTB) checklist of 25 reporting items to increase their relevance to finfish, amphibians, molluscs, and crustaceans and provided examples and explanations for each item. The checklist, known as STRADAS-aquatic, was developed and refined by an expert group of 14 transdisciplinary scientists with experience in test evaluation studies using field and experimental samples, in operation of reference laboratories for aquatic animal pathogens, and in development of international aquatic animal health policy. The main changes to the STRADAS-paraTB checklist were to nomenclature related to the species, the addition of guidelines for experimental challenge studies, and the designation of some items as relevant only to experimental studies and ante-mortem tests. We believe that adoption of these guidelines will improve reporting of primary studies of test accuracy for aquatic animal diseases and facilitate assessment of their fitness-for-purpose. Given the importance of diagnostic tests to underpin the Sanitary and Phytosanitary agreement of the World Trade Organization, the principles outlined in this paper should be applied to other World Organisation for Animal Health (OIE)-relevant species.

  17. Systematic review and meta-analysis of flow cytometry in urinary tract infection screening.

    PubMed

    Shang, Yan-Jun; Wang, Qian-Qian; Zhang, Jian-Rong; Xu, Yu-Lian; Zhang, Wei-Wei; Chen, Yan; Gu, Ming-Li; Hu, Zhi-De; Deng, An-Mei

    2013-09-23

    Automated urine sediment analysis of white blood cells (WBCs) and bacteria is a promising approach for urinary tract infections (UTIs) screening. However, available data on their screening efficacy is inconsistent. English articles from Pubmed, EMBASE, and Web of Science published before December 1, 2012 were analyzed. The Quality Assessment for Studies of Diagnostic Accuracy (QUADAS) tool was used to evaluate the quality of eligible studies. Performance characteristics of WBCs and bacteria (sensitivity, specificity, and other measures of accuracy) were pooled and examined by random-effects models. Nineteen studies containing 22,305 samples were included. Pooled sensitivities were 0.87 (95% confidence interval [CI], 0.86-0.89) for WBCs and 0.92 (95% CI, 0.91-0.93) for bacteria. Corresponding pooled specificities were 0.67 (95% CI, 0.66-0.68) for WBCs and 0.60 (95% CI, 0.59-0.61) for bacteria. Areas under the summary receiver operating characteristics curves were 0.87 and 0.93 for WBCs and bacteria, respectively. The major limitation of eligible studies was that enrolled subjects were often not representative of clinical patient populations in which UTI would be suspected. WBC and bacterial measurements by the UF-100 and UF-1000i are useful indicators in UTI screening; however, the performances of these systems should be rigorously evaluated by additional studies. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Sternal instability measured with radiostereometric analysis. A study of method feasibility, accuracy and precision.

    PubMed

    Vestergaard, Rikke Falsig; Søballe, Kjeld; Hasenkam, John Michael; Stilling, Maiken

    2018-05-18

    A small, but unstable, saw-gap may hinder bone-bridging and induce development of painful sternal dehiscence. We propose the use of Radiostereometric Analysis (RSA) for evaluation of sternal instability and present a method validation. Four bone analogs (phantoms) were sternotomized and tantalum beads were inserted in each half. The models were reunited with wire cerclage and placed in a radiolucent separation device. Stereoradiographs (n = 48) of the phantoms in 3 positions were recorded at 4 imposed separation points. The accuracy and precision was compared statistically and presented as translations along the 3 orthogonal axes. 7 sternotomized patients were evaluated for clinical RSA precision by double-examination stereoradiographs (n = 28). In the phantom study, we found no systematic error (p > 0.3) between the three phantom positions, and precision for evaluation of sternal separation was 0.02 mm. Phantom accuracy was mean 0.13 mm (SD 0.25). In the clinical study, we found a detection limit of 0.42 mm for sternal separation and of 2 mm for anterior-posterior dislocation of the sternal halves for the individual patient. RSA is a precise and low-dose image modality feasible for clinical evaluation of sternal stability in research. ClinicalTrials.gov Identifier: NCT02738437 , retrospectively registered.

  19. Accuracy of parameterized proton range models; A comparison

    NASA Astrophysics Data System (ADS)

    Pettersen, H. E. S.; Chaar, M.; Meric, I.; Odland, O. H.; Sølie, J. R.; Röhrich, D.

    2018-03-01

    An accurate calculation of proton ranges in phantoms or detector geometries is crucial for decision making in proton therapy and proton imaging. To this end, several parameterizations of the range-energy relationship exist, with different levels of complexity and accuracy. In this study we compare the accuracy of four different parameterizations models for proton range in water: Two analytical models derived from the Bethe equation, and two different interpolation schemes applied to range-energy tables. In conclusion, a spline interpolation scheme yields the highest reproduction accuracy, while the shape of the energy loss-curve is best reproduced with the differentiated Bragg-Kleeman equation.

  20. A Study of the Accuracy and Reliability of Articles about Alopecia in Newspapers

    PubMed Central

    Park, In Ho; Kim, Do Hyeong; Park, So Hee; Cho, Gyeong Je; Seol, Jung Eun

    2018-01-01

    Background There is growing interest in alopecia among the general population. Many people obtain information from easily accessible media rather than from doctors; thus, the media can play an important role in shaping public opinion. Objective The goal of this study was to evaluate the content and reliability of newspaper articles on alopecia. Methods Newspapers were categorized into three groups: one group of print newspapers and two groups of online newspapers. Online newspapers were further divided into two groups according to type of publishing company; one publishes both print and online newspapers and the other publishes online newspapers only. The most frequently subscribed or circulated newspaper in each group was selected. Articles containing information on alopecia were selected from 3 years of each newspaper and evaluated for reliability. Results Most articles in each group used the general term “alopecia” instead of naming a specific hair loss disease. The majority of articles were based on consultation with experts. Assessment of the accuracy of articles with three grade scales showed that the percentage with high accuracy was 38.9%, 47.2%, and 23.3%. Assessment of reliability scores for five selected articles in each group showed that there were statistically significant differences between common readers and dermatologists (p<0.05). Conclusion The results of this study suggest that closer monitoring of the media is required to supply easily accessible, balanced, and trustworthy information regarding alopecia. PMID:29853745

  1. The diagnostic value of polymerase chain reaction for Mycobacterium tuberculosis to distinguish intestinal tuberculosis from crohn's disease: A meta-analysis.

    PubMed

    Jin, Ting; Fei, Baoying; Zhang, Yu; He, Xujun

    2017-01-01

    Intestinal tuberculosis (ITB) and Crohn's disease (CD) are important differential diagnoses that can be difficult to distinguish. Polymerase chain reaction (PCR) for Mycobacterium tuberculosis (MTB) is an efficient and promising tool. This meta-analysis was performed to systematically and objectively assess the potential diagnostic accuracy and clinical value of PCR for MTB in distinguishing ITB from CD. We searched PubMed, Embase, Web of Science, Science Direct, and the Cochrane Library for eligible studies, and nine articles with 12 groups of data were identified. The included studies were subjected to quality assessment using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. The summary estimates were as follows: sensitivity 0.47 (95% CI: 0.42-0.51); specificity 0.95 (95% CI: 0.93-0.97); the positive likelihood ratio (PLR) 10.68 (95% CI: 6.98-16.35); the negative likelihood ratio (NLR) 0.49 (95% CI: 0.33-0.71); and diagnostic odds ratio (DOR) 21.92 (95% CI: 13.17-36.48). The area under the curve (AUC) was 0.9311, with a Q* value of 0.8664. Heterogeneity was found in the NLR. The heterogeneity of the studies was evaluated by meta-regression analysis and subgroup analysis. The current evidence suggests that PCR for MTB is a promising and highly specific diagnostic method to distinguish ITB from CD. However, physicians should also keep in mind that negative results cannot exclude ITB for its low sensitivity. Additional prospective studies are needed to further evaluate the diagnostic accuracy of PCR.

  2. Circulating miR-128 as a potential diagnostic biomarker for glioma.

    PubMed

    Liang, Ruo-Fei; Li, Mao; Yang, Yuan; Wang, Xiang; Mao, Qing; Liu, Yan-Hui

    2017-09-01

    miR-128 in circulation is a promising marker for early diagnosis of glioma. A meta-analysis was performed to evaluate the diagnostic accuracy and clinical value of circulating miR-128 in patients with glioma. A comprehensive literature search for relevant published articles (last search updated on December 29, 2016) was conducted in the Chinese Biomedical Literature Database, PubMed, and Embase. The quality assessment of diagnostic accuracy studies (QUADAS) tool was used to score the quality of the eligible studies. Meta-Disc 1.4 software was used to test for heterogeneity and to perform the meta-analysis. The three studies included in our study enrolled a total of 191 patients with glioma and 73 individuals without tumor. Using a fixed-effect model analysis, the summary assessments revealed that the pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio were 0.89 (95% CI: 0.84-0.93), 0.90 (95% CI: 0.81-0.96), 8.07 (95% CI: 4.21-15.46), and 0.13 (95% CI: 0.09-0.19), respectively. The diagnostic odds ratio (DOR) of miR-128 was 65.00 (95% CI: 26.90-157.10), indicating that the overall accuracy of the miR-128 test for detecting glioma was high. The value of I 2 was 0.0%, indicating that there was no significant heterogeneity among studies. The present meta-analysis showed that circulating miR-128 might be a promising noninvasive biomarker for diagnosing glioma. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. The HEART score for early rule out of acute coronary syndromes in the emergency department: a systematic review and meta-analysis.

    PubMed

    Van Den Berg, Patricia; Body, Richard

    2018-03-01

    The objective of this systematic review was to summarise the current evidence on the diagnostic accuracy of the HEART score for predicting major adverse cardiac events in patients presenting with undifferentiated chest pain to the emergency department. Two investigators independently searched Medline, Embase and Cochrane databases between 2008 and May 2016 identifying eligible studies providing diagnostic accuracy data on the HEART score for predicting major adverse cardiac events as the primary outcome. For the 12 studies meeting inclusion criteria, study characteristics and diagnostic accuracy measures were systematically extracted and study quality assessed using the QUADAS-2 tool. After quality assessment, nine studies including data from 11,217 patients were combined in the meta-analysis applying a generalised linear mixed model approach with random effects assumption (Stata 13.1). In total, 15.4% of patients (range 7.3-29.1%) developed major adverse cardiac events after a mean of 6 weeks' follow-up. Among patients categorised as 'low risk' and suitable for early discharge (HEART score 0-3), the pooled incidence of 'missed' major adverse cardiac events was 1.6%. The pooled sensitivity and specificity of the HEART score for predicting major adverse cardiac events were 96.7% (95% confidence interval (CI) 94.0-98.2%) and 47.0% (95% CI 41.0-53.5%), respectively. Patients with a HEART score of 0-3 are at low risk of incident major adverse cardiac events. As 3.3% of patients with major adverse cardiac events are 'missed' by the HEART score, clinicians must ask whether this risk is acceptably low for clinical implementation.

  4. Dimensional Accuracy of Hydrophilic and Hydrophobic VPS Impression Materials Using Different Impression Techniques - An Invitro Study

    PubMed Central

    Pilla, Ajai; Pathipaka, Suman

    2016-01-01

    Introduction The dimensional stability of the impression material could have an influence on the accuracy of the final restoration. Vinyl Polysiloxane Impression materials (VPS) are most frequently used as the impression material in fixed prosthodontics. As VPS is hydrophobic when it is poured with gypsum products, manufacturers added intrinsic surfactants and marketed as hydrophilic VPS. These hydrophilic VPS have shown increased wettability with gypsum slurries. VPS are available in different viscosities ranging from very low to very high for usage under different impression techniques. Aim To compare the dimensional accuracy of hydrophilic VPS and hydrophobic VPS using monophase, one step and two step putty wash impression techniques. Materials and Methods To test the dimensional accuracy of the impression materials a stainless steel die was fabricated as prescribed by ADA specification no. 19 for elastomeric impression materials. A total of 60 impressions were made. The materials were divided into two groups, Group1 hydrophilic VPS (Aquasil) and Group 2 hydrophobic VPS (Variotime). These were further divided into three subgroups A, B, C for monophase, one-step and two-step putty wash technique with 10 samples in each subgroup. The dimensional accuracy of the impressions was evaluated after 24 hours using vertical profile projector with lens magnification range of 20X-125X illumination. The study was analyzed through one-way ANOVA, post-hoc Tukey HSD test and unpaired t-test for mean comparison between groups. Results Results showed that the three different impression techniques (monophase, 1-step, 2-step putty wash techniques) did cause significant change in dimensional accuracy between hydrophilic VPS and hydrophobic VPS impression materials. One-way ANOVA disclosed, mean dimensional change and SD for hydrophilic VPS varied between 0.56% and 0.16%, which were low, suggesting hydrophilic VPS was satisfactory with all three impression techniques. However, mean

  5. Social Power Increases Interoceptive Accuracy

    PubMed Central

    Moeini-Jazani, Mehrad; Knoeferle, Klemens; de Molière, Laura; Gatti, Elia; Warlop, Luk

    2017-01-01

    Building on recent psychological research showing that power increases self-focused attention, we propose that having power increases accuracy in perception of bodily signals, a phenomenon known as interoceptive accuracy. Consistent with our proposition, participants in a high-power experimental condition outperformed those in the control and low-power conditions in the Schandry heartbeat-detection task. We demonstrate that the effect of power on interoceptive accuracy is not explained by participants’ physiological arousal, affective state, or general intention for accuracy. Rather, consistent with our reasoning that experiencing power shifts attentional resources inward, we show that the effect of power on interoceptive accuracy is dependent on individuals’ chronic tendency to focus on their internal sensations. Moreover, we demonstrate that individuals’ chronic sense of power also predicts interoceptive accuracy similar to, and independent of, how their situationally induced feeling of power does. We therefore provide further support on the relation between power and enhanced perception of bodily signals. Our findings offer a novel perspective–a psychophysiological account–on how power might affect judgments and behavior. We highlight and discuss some of these intriguing possibilities for future research. PMID:28824501

  6. Accuracy investigation of phthalate metabolite standards.

    PubMed

    Langlois, Éric; Leblanc, Alain; Simard, Yves; Thellen, Claude

    2012-05-01

    Phthalates are ubiquitous compounds whose metabolites are usually determined in urine for biomonitoring studies. Following suspect and unexplained results from our laboratory in an external quality-assessment scheme, we investigated the accuracy of all phthalate metabolite standards in our possession by comparing them with those of several suppliers. Our findings suggest that commercial phthalate metabolite certified solutions are not always accurate and that lot-to-lot discrepancies significantly affect the accuracy of the results obtained with several of these standards. These observations indicate that the reliability of the results obtained from different lots of standards is not equal, which reduces the possibility of intra-laboratory and inter-laboratory comparisons of results. However, agreements of accuracy have been observed for a majority of neat standards obtained from different suppliers, which indicates that a solution to this issue is available. Data accuracy of phthalate metabolites should be of concern for laboratories performing phthalate metabolite analysis because of the standards used. The results of our investigation are presented from the perspective that laboratories performing phthalate metabolite analysis can obtain accurate and comparable results in the future. Our findings will contribute to improving the quality of future phthalate metabolite analyses and will affect the interpretation of past results.

  7. Evaluation of accuracy of IHI Trigger Tool in identifying adverse drug events: a prospective observational study.

    PubMed

    das Dores Graciano Silva, Maria; Martins, Maria Auxiliadora Parreiras; de Gouvêa Viana, Luciana; Passaglia, Luiz Guilherme; de Menezes, Renata Rezende; de Queiroz Oliveira, João Antonio; da Silva, Jose Luiz Padilha; Ribeiro, Antonio Luiz Pinho

    2018-06-06

    Adverse drug events (ADEs) can seriously compromise the safety and quality of care provided to hospitalized patients, requiring the adoption of accurate methods to monitor them. We sought to prospectively evaluate the accuracy of the triggers proposed by the Institute for Healthcare Improvement (IHI) for identifying ADEs. A prospective study was conducted in a public university hospital, in 2015, with patients ≥18 years. Triggers proposed by IHI and clinical alterations suspected to be ADEs were searched daily. The number of days in which the patient was hospitalized was considered as unit of measure to evaluate the accuracy of each trigger. Three hundred patients were included in this study. Mean age was 56.3 years (standard deviation (SD) 16.0), and 154 (51.3%) were female. The frequency of patients with ADEs was 24.7% and with at least one trigger was 53.3%. From those patients who had at least one trigger, the most frequent triggers were antiemetics (57.5%) and "abrupt medication stop" (31.8%). Triggers' sensitivity ranged from 0.3 to11.8 % and the positive predictive value ranged from 1.2 to 27.3%. Specificity and negative predictive value were greater than 86%. Most patients identified by the presence of triggers did not have ADEs (64.4%). No triggers were identified in 40 (38.5%) ADEs. IHI Trigger Tool did not show good accuracy in detecting ADEs in this prospective study. The adoption of combined strategies could enhance effectiveness in identifying patient safety flaws. Further discussion might contribute to improve trigger usefulness in clinical practice. This article is protected by copyright. All rights reserved.

  8. Recognition of out-of-hospital cardiac arrest during emergency calls - a systematic review of observational studies.

    PubMed

    Viereck, Søren; Møller, Thea Palsgaard; Rothman, Josephine Philip; Folke, Fredrik; Lippert, Freddy Knudsen

    2017-02-01

    The medical dispatcher plays an essential role as part of the first link in the Chain of Survival, by recognising the out-of-hospital cardiac arrest (OHCA) during the emergency call, dispatching the appropriate first responder or emergency medical services response, performing dispatcher assisted cardiopulmonary resuscitation, and referring to the nearest automated external defibrillator. The objective of this systematic review was to evaluate and compare studies reporting recognition of OHCA patients during emergency calls. This systematic review was reported in compliance with the PRISMA guidelines. We systematically searched MEDLINE, Embase and the Cochrane Library on 4 November 2015. Observational studies, reporting the proportion of clinically confirmed OHCAs that was recognised during the emergency call, were included. Two authors independently screened abstracts and full-text articles for inclusion. Data were extracted and the risk of bias within studies was assessed using the QUADAS-2 tool for quality assessment of diagnostic accuracy studies. A total of 3,180 abstracts were screened for eligibility and 53 publications were assessed in full-text. We identified 16 studies including 6,955 patients that fulfilled the criteria for inclusion in the systematic review. The studies reported recognition of OHCA with a median sensitivity of 73.9% (range: 14.1-96.9%). The selection of study population and the definition of "recognised OHCA" (threshold for positive test) varied greatly between the studies, resulting in high risk of bias. Heterogeneity in the studies precluded meta-analysis. Among the 16 included studies, we found a median sensitivity for OHCA recognition of 73.9% (range: 14.1-96.9%). However, great heterogeneity between study populations and in the definition of "recognised OHCA", lead to insufficient comparability of results. Uniform and transparent reporting is required to ensure comparability and development towards best practice.

  9. Accuracy of digital images in the detection of marginal microleakage: an in vitro study.

    PubMed

    Alvarenga, Fábio Augusto; Andrade, Marcelo Ferrarezi; Pinelli, Camila; Rastelli, Alessanda Nara; Victorino, Keli Regina; Loffredo, Leonor de

    2012-08-01

    To evaluate the accuracy of Image Tool Software 3.0 (ITS 3.0) to detect marginal microleakage using the stereomicroscope as the validation criterion and ITS 3.0 as the tool under study. Class V cavities were prepared at the cementoenamel junction of 61 bovine incisors, and 53 halves of them were used. Using the stereomicroscope, microleakage was classified dichotomously: presence or absence. Next, ITS 3.0 was used to obtain measurements of the microleakage, so that 0.75 was taken as the cut-off point, and values equal to or greater than 0.75 indicated its presence, while values between 0.00 and 0.75 indicated its absence. Sensitivity and specificity were calculated by point and given as 95% confidence interval (95% CI). The accuracy of the ITS 3.0 was verified with a sensitivity of 0.95 (95% CI: 0.89 to 1.00) and a specificity of 0.92 (95% CI: 0.84 to 0.99). Digital diagnosis of marginal microleakage using ITS 3.0 was sensitive and specific.

  10. Factors affecting GEBV accuracy with single-step Bayesian models.

    PubMed

    Zhou, Lei; Mrode, Raphael; Zhang, Shengli; Zhang, Qin; Li, Bugao; Liu, Jian-Feng

    2018-01-01

    A single-step approach to obtain genomic prediction was first proposed in 2009. Many studies have investigated the components of GEBV accuracy in genomic selection. However, it is still unclear how the population structure and the relationships between training and validation populations influence GEBV accuracy in terms of single-step analysis. Here, we explored the components of GEBV accuracy in single-step Bayesian analysis with a simulation study. Three scenarios with various numbers of QTL (5, 50, and 500) were simulated. Three models were implemented to analyze the simulated data: single-step genomic best linear unbiased prediction (GBLUP; SSGBLUP), single-step BayesA (SS-BayesA), and single-step BayesB (SS-BayesB). According to our results, GEBV accuracy was influenced by the relationships between the training and validation populations more significantly for ungenotyped animals than for genotyped animals. SS-BayesA/BayesB showed an obvious advantage over SSGBLUP with the scenarios of 5 and 50 QTL. SS-BayesB model obtained the lowest accuracy with the 500 QTL in the simulation. SS-BayesA model was the most efficient and robust considering all QTL scenarios. Generally, both the relationships between training and validation populations and LD between markers and QTL contributed to GEBV accuracy in the single-step analysis, and the advantages of single-step Bayesian models were more apparent when the trait is controlled by fewer QTL.

  11. Meta-analysis of diagnostic accuracy studies accounting for disease prevalence: alternative parameterizations and model selection.

    PubMed

    Chu, Haitao; Nie, Lei; Cole, Stephen R; Poole, Charles

    2009-08-15

    In a meta-analysis of diagnostic accuracy studies, the sensitivities and specificities of a diagnostic test may depend on the disease prevalence since the severity and definition of disease may differ from study to study due to the design and the population considered. In this paper, we extend the bivariate nonlinear random effects model on sensitivities and specificities to jointly model the disease prevalence, sensitivities and specificities using trivariate nonlinear random-effects models. Furthermore, as an alternative parameterization, we also propose jointly modeling the test prevalence and the predictive values, which reflect the clinical utility of a diagnostic test. These models allow investigators to study the complex relationship among the disease prevalence, sensitivities and specificities; or among test prevalence and the predictive values, which can reveal hidden information about test performance. We illustrate the proposed two approaches by reanalyzing the data from a meta-analysis of radiological evaluation of lymph node metastases in patients with cervical cancer and a simulation study. The latter illustrates the importance of carefully choosing an appropriate normality assumption for the disease prevalence, sensitivities and specificities, or the test prevalence and the predictive values. In practice, it is recommended to use model selection techniques to identify a best-fitting model for making statistical inference. In summary, the proposed trivariate random effects models are novel and can be very useful in practice for meta-analysis of diagnostic accuracy studies. Copyright 2009 John Wiley & Sons, Ltd.

  12. Assessment of the Thematic Accuracy of Land Cover Maps

    NASA Astrophysics Data System (ADS)

    Höhle, J.

    2015-08-01

    Several land cover maps are generated from aerial imagery and assessed by different approaches. The test site is an urban area in Europe for which six classes (`building', `hedge and bush', `grass', `road and parking lot', `tree', `wall and car port') had to be derived. Two classification methods were applied (`Decision Tree' and `Support Vector Machine') using only two attributes (height above ground and normalized difference vegetation index) which both are derived from the images. The assessment of the thematic accuracy applied a stratified design and was based on accuracy measures such as user's and producer's accuracy, and kappa coefficient. In addition, confidence intervals were computed for several accuracy measures. The achieved accuracies and confidence intervals are thoroughly analysed and recommendations are derived from the gained experiences. Reliable reference values are obtained using stereovision, false-colour image pairs, and positioning to the checkpoints with 3D coordinates. The influence of the training areas on the results is studied. Cross validation has been tested with a few reference points in order to derive approximate accuracy measures. The two classification methods perform equally for five classes. Trees are classified with a much better accuracy and a smaller confidence interval by means of the decision tree method. Buildings are classified by both methods with an accuracy of 99% (95% CI: 95%-100%) using independent 3D checkpoints. The average width of the confidence interval of six classes was 14% of the user's accuracy.

  13. Social power facilitates the effect of prosocial orientation on empathic accuracy.

    PubMed

    Côté, Stéphane; Kraus, Michael W; Cheng, Bonnie Hayden; Oveis, Christopher; van der Löwe, Ilmo; Lian, Hua; Keltner, Dacher

    2011-08-01

    Power increases the tendency to behave in a goal-congruent fashion. Guided by this theoretical notion, we hypothesized that elevated power would strengthen the positive association between prosocial orientation and empathic accuracy. In 3 studies with university and adult samples, prosocial orientation was more strongly associated with empathic accuracy when distinct forms of power were high than when power was low. In Study 1, a physiological indicator of prosocial orientation, respiratory sinus arrhythmia, exhibited a stronger positive association with empathic accuracy in a face-to-face interaction among dispositionally high-power individuals. In Study 2, experimentally induced prosocial orientation increased the ability to accurately judge the emotions of a stranger but only for individuals induced to feel powerful. In Study 3, a trait measure of prosocial orientation was more strongly related to scores on a standard test of empathic accuracy among employees who occupied high-power positions within an organization. Study 3 further showed a mediated relationship between prosocial orientation and career satisfaction through empathic accuracy among employees in high-power positions but not among employees in lower power positions. Discussion concentrates upon the implications of these findings for studies of prosociality, power, and social behavior.

  14. Thermocouple Calibration and Accuracy in a Materials Testing Laboratory

    NASA Technical Reports Server (NTRS)

    Lerch, B. A.; Nathal, M. V.; Keller, D. J.

    2002-01-01

    A consolidation of information has been provided that can be used to define procedures for enhancing and maintaining accuracy in temperature measurements in materials testing laboratories. These studies were restricted to type R and K thermocouples (TCs) tested in air. Thermocouple accuracies, as influenced by calibration methods, thermocouple stability, and manufacturer's tolerances were all quantified in terms of statistical confidence intervals. By calibrating specific TCs the benefits in accuracy can be as great as 6 C or 5X better compared to relying on manufacturer's tolerances. The results emphasize strict reliance on the defined testing protocol and on the need to establish recalibration frequencies in order to maintain these levels of accuracy.

  15. Accuracy of acromioclavicular joint injections.

    PubMed

    Wasserman, Bradley R; Pettrone, Sarah; Jazrawi, Laith M; Zuckerman, Joseph D; Rokito, Andrew S

    2013-01-01

    Injection to the acromioclavicular (AC) joint can be both diagnostic and therapeutic. The purpose of this study was to evaluate the accuracy of in vivo AC joint injections. Case series; Level of evidence, 4. Thirty patients with pain localized to the AC joint were injected with 1 mL of 1% lidocaine and 0.5 mL of radiographic contrast material (Isovue). Radiographs of the AC joint were taken after the injection. Each radiograph was reviewed by a musculoskeletal radiologist and graded as intra-articular, extra-articular, or partially intra-articular. Of the 30 injections performed, 13 (43.3%) were intra-articular, 7 (23.3%) were partially articular, and 10 (33.3%) were extra-articular. When the intra-articular and the partially articular groups were combined, 20 patients (66.7%) had some contrast dye in the AC joint. This study demonstrates that despite the relatively superficial location of the AC joint, the clinical accuracy of AC joint injections remains relatively low.

  16. The accuracy of caries risk assessment in children attending South Australian School Dental Service: a longitudinal study

    PubMed Central

    Ha, Diep H; Spencer, A John; Slade, Gary D; Chartier, Andrew D

    2014-01-01

    Objectives To determine the accuracy of the caries risk assessment system and performance of clinicians in their attempts to predict caries for children during routine practice. Design Longitudinal study. Setting and participants Data on caries risk assessment conducted by clinicians during routine practice while providing care for children in the South Australian School Dental Service (SA SDS) were collected from electronic patient records. Baseline data on caries experience, clinicians’ ratings of caries risk status and child demographics were obtained for all SA SDS patients aged 5–15 years examined during 2002–2005. Outcome measure Children’s caries incidence rate, calculated using examination data after a follow-up period of 6–48 months from baseline, was used as the gold standard to compute the sensitivity (Se) and specificity (Sp) of clinicians’ baseline ratings of caries risk. Multivariate binomial regression models were used to evaluate effects of children's baseline characteristics on Se and Sp. Results A total of 133 clinicians rated caries risk status of 71 430 children during 2002–2005. The observed Se and Sp were 0.48 and 0.86, respectively (Se+Sp=1.34). Caries experience at baseline was the strongest factor influencing accuracy in multivariable regression model. Among children with no caries experience at baseline, overall accuracy (Se+Sp) was only 1.05, whereas it was 1.28 among children with at least one tooth surfaces with caries experience at baseline. Conclusions Clinicians’ accuracy in predicting caries risk during routine practice was similar to levels reported in research settings that simulated patient care. Accuracy was acceptable in children who had prior caries experience at the baseline examination, while it was poor among children with no caries experience. PMID:24477318

  17. The use of video in standardized patient training to improve portrayal accuracy: A randomized post-test control group study.

    PubMed

    Schlegel, Claudia; Bonvin, Raphael; Rethans, Jan Joost; van der Vleuten, Cees

    2014-10-14

    Abstract Introduction: High-stake objective structured clinical examinations (OSCEs) with standardized patients (SPs) should offer the same conditions to all candidates throughout the exam. SP performance should therefore be as close to the original role script as possible during all encounters. In this study, we examined the impact of video in SP training on SPs' role accuracy, investigating how the use of different types of video during SP training improves the accuracy of SP portrayal. Methods: In a randomized post-test, control group design three groups of 12 SPs each with different types of video training and one control group of 12 SPs without video use in SP training were compared. The three intervention groups used role-modeling video, performance-feedback video, or a combination of both. Each SP from each group had four students encounter. Two blinded faculty members rated the 192 video-recorded encounters, using a case-specific rating instrument to assess SPs' role accuracy. Results: SPs trained by video showed significantly (p < 0.001) better role accuracy than SPs trained without video over the four sequential portrayals. There was no difference between the three types of video training. Discussion: Use of video during SP training enhances the accuracy of SP portrayal compared with no video, regardless of the type of video intervention used.

  18. Fast and Confident: Postdicting Eyewitness Identification Accuracy in a Field Study

    ERIC Educational Resources Information Center

    Sauerland, Melanie; Sporer, Siegfried L.

    2009-01-01

    The combined postdictive value of postdecision confidence, decision time, and Remember-Know-Familiar (RKF) judgments as markers of identification accuracy was evaluated with 10 targets and 720 participants. In a pedestrian area, passers-by were asked for directions. Identifications were made from target-absent or target-present lineups. Fast…

  19. About the inevitable compromise between spatial resolution and accuracy of strain measurement for bone tissue: a 3D zero-strain study.

    PubMed

    Dall'Ara, E; Barber, D; Viceconti, M

    2014-09-22

    The accurate measurement of local strain is necessary to study bone mechanics and to validate micro computed tomography (µCT) based finite element (FE) models at the tissue scale. Digital volume correlation (DVC) has been used to provide a volumetric estimation of local strain in trabecular bone sample with a reasonable accuracy. However, nothing has been reported so far for µCT based analysis of cortical bone. The goal of this study was to evaluate accuracy and precision of a deformable registration method for prediction of local zero-strains in bovine cortical and trabecular bone samples. The accuracy and precision were analyzed by comparing scans virtually displaced, repeated scans without any repositioning of the sample in the scanner and repeated scans with repositioning of the samples. The analysis showed that both precision and accuracy errors decrease with increasing the size of the region analyzed, by following power laws. The main source of error was found to be the intrinsic noise of the images compared to the others investigated. The results, once extrapolated for larger regions of interest that are typically used in the literature, were in most cases better than the ones previously reported. For a nodal spacing equal to 50 voxels (498 µm), the accuracy and precision ranges were 425-692 µε and 202-394 µε, respectively. In conclusion, it was shown that the proposed method can be used to study the local deformation of cortical and trabecular bone loaded beyond yield, if a sufficiently high nodal spacing is used. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Diagnostic accuracy study of anorectal manometry for diagnosis of dyssynergic defaecation

    PubMed Central

    Grossi, Ugo; Carrington, Emma V; Bharucha, Adil E; Horrocks, Emma J; Scott, S Mark; Knowles, Charles H

    2015-01-01

    Objective The diagnostic accuracy of anorectal manometry (AM), which is necessary to diagnose functional defaecatory disorders (FDD), is unknown. Using blinded analysis and standardised reporting of diagnostic accuracy (STARD), we evaluated whether AM could discriminate between asymptomatic controls and patients with functional constipation (FC). Design Derived line-plots of anorectal pressure profiles during simulated defaecation were independently analysed in random order by 3 expert observers blinded to health status in 85 women with FC and 85 age-matched asymptomatic healthy volunteers (HV). Using accepted criteria, these pressure profiles were characterized as normal (i.e. increased rectal pressure coordinated with anal relaxation) or types I-IV dyssynergia. Inter-observer agreement and diagnostic accuracy were determined. Results Blinded consensus-based assessment disclosed a normal pattern in 16/170 (9%) of all participants and only 11/85 (13%) HV. The combined frequency of dyssynergic patterns (I-IV) was very similar in FC (80/85 [94%]) and HV (74/85 [87%]). Type I dyssynergia (‘paradoxical’ contraction) was less prevalent in FC (17/85 [20%] than HV (31/85 [36.5%], p=0.03). After statistical correction, only type IV dyssynergia was moderately useful for discriminating between FC (39/85 [46%] and HV 17/85 [20%], p=0.001, PPV=70.0%, positive LR=2.3). Inter-observer agreement was substantial or moderate for identifying a normal pattern, dyssynergia types I and IV, and FDD, and fair for types II and III. Conclusions While the interpretation of AM patterns is reproducible, nearly 90% of HV have a pattern that is currently regarded as “abnormal” by AM. Hence AM is of limited utility for distinguishing between FC and HV. PMID:25765461

  1. Diagnostic Accuracy of Chinese Medicine Diagnosis Scale of Phlegm and Blood Stasis Syndrome in Coronary Heart Disease: A Study Protocol.

    PubMed

    Liu, Xiao-Qi; Peng, Dan-Hong; Wang, Yan-Ping; Xie, Rong; Chen, Xin-Lin; Yu, Chun-Quan; Li, Xian-Tao

    2018-05-03

    Phlegm and blood stasis syndrome (PBSS) is one of the main syndromes in coronary heart disease (CHD). Syndromes of Chinese medicine (CM) are lack of quantitative and easyimplementation diagnosis standards. To quantify and standardize the diagnosis of PBSS, scales are usually applied. To evaluate the diagnostic accuracy of CM diagnosis scale of PBSS in CHD. Six hundred patients with stable angina pectoris of CHD, 300 in case group and 300 in control group, will be recruited from 5 hospitals across China. Diagnosis from 2 experts will be considered as the "gold standard". The study design consists of 2 phases: pilot test is used to evaluate the reliability and validity, and diagnostic test is used to assess the diagnostic accuracy of the scale, including sensitivity, specififi city, likelihood ratio and area under the receiver operator characteristic (ROC) curve. This study will evaluate the diagnostic accuracy of CM diagnosis scale of PBSS in CHD. The consensus of 2 experts may not be ideal as a "gold standard", and itself still requires further study. (No. ChiCTR-OOC-15006599).

  2. Impacts of land use/cover classification accuracy on regional climate simulations

    NASA Astrophysics Data System (ADS)

    Ge, Jianjun; Qi, Jiaguo; Lofgren, Brent M.; Moore, Nathan; Torbick, Nathan; Olson, Jennifer M.

    2007-03-01

    Land use/cover change has been recognized as a key component in global change. Various land cover data sets, including historically reconstructed, recently observed, and future projected, have been used in numerous climate modeling studies at regional to global scales. However, little attention has been paid to the effect of land cover classification accuracy on climate simulations, though accuracy assessment has become a routine procedure in land cover production community. In this study, we analyzed the behavior of simulated precipitation in the Regional Atmospheric Modeling System (RAMS) over a range of simulated classification accuracies over a 3 month period. This study found that land cover accuracy under 80% had a strong effect on precipitation especially when the land surface had a greater control of the atmosphere. This effect became stronger as the accuracy decreased. As shown in three follow-on experiments, the effect was further influenced by model parameterizations such as convection schemes and interior nudging, which can mitigate the strength of surface boundary forcings. In reality, land cover accuracy rarely obtains the commonly recommended 85% target. Its effect on climate simulations should therefore be considered, especially when historically reconstructed and future projected land covers are employed.

  3. Dem Local Accuracy Patterns in Land-Use/Land-Cover Classification

    NASA Astrophysics Data System (ADS)

    Katerji, Wassim; Farjas Abadia, Mercedes; Morillo Balsera, Maria del Carmen

    2016-01-01

    Global and nation-wide DEM do not preserve the same height accuracy throughout the area of study. Instead of assuming a single RMSE value for the whole area, this study proposes a vario-model that divides the area into sub-regions depending on the land-use / landcover (LULC) classification, and assigns a local accuracy per each zone, as these areas share similar terrain formation and roughness, and tend to have similar DEM accuracies. A pilot study over Lebanon using the SRTM and ASTER DEMs, combined with a set of 1,105 randomly distributed ground control points (GCPs) showed that even though the inputDEMs have different spatial and temporal resolution, and were collected using difierent techniques, their accuracy varied similarly when changing over difierent LULC classes. Furthermore, validating the generated vario-models proved that they provide a closer representation of the accuracy to the validating GCPs than the conventional RMSE, by 94% and 86% for the SRTMand ASTER respectively. Geostatistical analysis of the input and output datasets showed that the results have a normal distribution, which support the generalization of the proven hypothesis, making this finding applicable to other input datasets anywhere around the world.

  4. Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel

    NASA Astrophysics Data System (ADS)

    Jia, Yunhai; Lu, Xuejun; Li, Jiangang; Zhu, Lixin; Song, Yingjie

    2011-05-01

    Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.

  5. Accuracy of Focused Assessment with Sonography for Trauma (FAST) in Blunt Trauma Abdomen-A Prospective Study.

    PubMed

    Kumar, Subodh; Bansal, Virinder Kumar; Muduly, Dillip Kumar; Sharma, Pawan; Misra, Mahesh C; Chumber, Sunil; Singh, Saraman; Bhardwaj, D N

    2015-12-01

    Focused assessment with sonography for trauma (FAST) is a limited ultrasound examination, primarily aimed at the identification of the presence of free intraperitoneal or pericardial fluid. In the context of blunt trauma abdomen (BTA), free fluid is usually due to hemorrhage, bowel contents, or both; contributes towards the timely diagnosis of potentially life-threatening hemorrhage; and is a decision-making tool to help determine the need for further evaluation or operative intervention. Fifty patients with blunt trauma abdomen were evaluated prospectively with FAST. The findings of FAST were compared with contrast-enhanced computed tomography (CECT), laparotomy, and autopsy. Any free fluid in the abdomen was presumed to be hemoperitoneum. Sonographic findings of intra-abdominal free fluid were confirmed by CECT, laparotomy, or autopsy wherever indicated. In comparing with CECT scan, FAST had a sensitivity, specificity, and accuracy of 77.27, 100, and 79.16 %, respectively, in the detection of free fluid. When compared with surgical findings, it had a sensitivity, specificity, and accuracy of 94.44, 50, and 90 %, respectively. The sensitivity of FAST was 75 % in determining free fluid in patients who died when compared with autopsy findings. Overall sensitivity, specificity, and accuracy of FAST were 80.43, 75 and 80 %, respectively, for the detection of free fluid in the abdomen. From this study, we can safely conclude that FAST is a rapid, reliable, and feasible investigation in patients with BTA, and it can be performed easily, safely, and quickly in the emergency room with a reasonable sensitivity, specificity, and accuracy. It helps in the initial triage of patients for assessing the need for urgent surgery.

  6. Theta Neurofeedback Effects on Motor Memory Consolidation and Performance Accuracy: An Apparent Paradox?

    PubMed

    Reiner, Miriam; Lev, Dror D; Rosen, Amit

    2018-05-15

    Previous studies have shown that theta neurofeedback enhances motor memory consolidation on an easy-to-learn finger-tapping task. However, the simplicity of the finger-tapping task precludes evaluating the putative effects of elevated theta on performance accuracy. Mastering a motor sequence is classically assumed to entail faster performance with fewer errors. The speed-accuracy tradeoff (SAT) principle states that as action speed increases, motor performance accuracy decreases. The current study investigated whether theta neurofeedback could improve both performance speed and performance accuracy, or would only enhance performance speed at the cost of reduced accuracy. A more complex task was used to study the effects of parietal elevated theta on 45 healthy volunteers The findings confirmed previous results on the effects of theta neurofeedback on memory consolidation. In contrast to the two control groups, in the theta-neurofeedback group the speed-accuracy tradeoff was reversed. The speed-accuracy tradeoff patterns only stabilized after a night's sleep implying enhancement in terms of both speed and accuracy. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  7. Added value of cost-utility analysis in simple diagnostic studies of accuracy: (18)F-fluoromethylcholine PET/CT in prostate cancer staging.

    PubMed

    Gerke, Oke; Poulsen, Mads H; Høilund-Carlsen, Poul Flemming

    2015-01-01

    Diagnostic studies of accuracy targeting sensitivity and specificity are commonly done in a paired design in which all modalities are applied in each patient, whereas cost-effectiveness and cost-utility analyses are usually assessed either directly alongside to or indirectly by means of stochastic modeling based on larger randomized controlled trials (RCTs). However the conduct of RCTs is hampered in an environment such as ours, in which technology is rapidly evolving. As such, there is a relatively limited number of RCTs. Therefore, we investigated as to which extent paired diagnostic studies of accuracy can be also used to shed light on economic implications when considering a new diagnostic test. We propose a simple decision tree model-based cost-utility analysis of a diagnostic test when compared to the current standard procedure and exemplify this approach with published data from lymph node staging of prostate cancer. Average procedure costs were taken from the Danish Diagnosis Related Groups Tariff in 2013 and life expectancy was estimated for an ideal 60 year old patient based on prostate cancer stage and prostatectomy or radiation and chemotherapy. Quality-adjusted life-years (QALYs) were deduced from the literature, and an incremental cost-effectiveness ratio (ICER) was used to compare lymph node dissection with respective histopathological examination (reference standard) and (18)F-fluoromethylcholine positron emission tomography/computed tomography (FCH-PET/CT). Lower bounds of sensitivity and specificity of FCH-PET/CT were established at which the replacement of the reference standard by FCH-PET/CT comes with a trade-off between worse effectiveness and lower costs. Compared to the reference standard in a diagnostic accuracy study, any imperfections in accuracy of a diagnostic test imply that replacing the reference standard generates a loss in effectiveness and utility. We conclude that diagnostic studies of accuracy can be put to a more extensive use

  8. Predictive accuracy of risk scales following self-harm: multicentre, prospective cohort study.

    PubMed

    Quinlivan, Leah; Cooper, Jayne; Meehan, Declan; Longson, Damien; Potokar, John; Hulme, Tom; Marsden, Jennifer; Brand, Fiona; Lange, Kezia; Riseborough, Elena; Page, Lisa; Metcalfe, Chris; Davies, Linda; O'Connor, Rory; Hawton, Keith; Gunnell, David; Kapur, Nav

    2017-06-01

    Background Scales are widely used in psychiatric assessments following self-harm. Robust evidence for their diagnostic use is lacking. Aims To evaluate the performance of risk scales (Manchester Self-Harm Rule, ReACT Self-Harm Rule, SAD PERSONS scale, Modified SAD PERSONS scale, Barratt Impulsiveness Scale); and patient and clinician estimates of risk in identifying patients who repeat self-harm within 6 months. Method A multisite prospective cohort study was conducted of adults aged 18 years and over referred to liaison psychiatry services following self-harm. Scale a priori cut-offs were evaluated using diagnostic accuracy statistics. The area under the curve (AUC) was used to determine optimal cut-offs and compare global accuracy. Results In total, 483 episodes of self-harm were included in the study. The episode-based 6-month repetition rate was 30% ( n = 145). Sensitivity ranged from 1% (95% CI 0-5) for the SAD PERSONS scale, to 97% (95% CI 93-99) for the Manchester Self-Harm Rule. Positive predictive values ranged from 13% (95% CI 2-47) for the Modified SAD PERSONS Scale to 47% (95% CI 41-53) for the clinician assessment of risk. The AUC ranged from 0.55 (95% CI 0.50-0.61) for the SAD PERSONS scale to 0.74 (95% CI 0.69-0.79) for the clinician global scale. The remaining scales performed significantly worse than clinician and patient estimates of risk ( P <0.001). Conclusions Risk scales following self-harm have limited clinical utility and may waste valuable resources. Most scales performed no better than clinician or patient ratings of risk. Some performed considerably worse. Positive predictive values were modest. In line with national guidelines, risk scales should not be used to determine patient management or predict self-harm. © The Royal College of Psychiatrists 2017.

  9. Source localization of rhythmic ictal EEG activity: a study of diagnostic accuracy following STARD criteria.

    PubMed

    Beniczky, Sándor; Lantz, Göran; Rosenzweig, Ivana; Åkeson, Per; Pedersen, Birthe; Pinborg, Lars H; Ziebell, Morten; Jespersen, Bo; Fuglsang-Frederiksen, Anders

    2013-10-01

    Although precise identification of the seizure-onset zone is an essential element of presurgical evaluation, source localization of ictal electroencephalography (EEG) signals has received little attention. The aim of our study was to estimate the accuracy of source localization of rhythmic ictal EEG activity using a distributed source model. Source localization of rhythmic ictal scalp EEG activity was performed in 42 consecutive cases fulfilling inclusion criteria. The study was designed according to recommendations for studies on diagnostic accuracy (STARD). The initial ictal EEG signals were selected using a standardized method, based on frequency analysis and voltage distribution of the ictal activity. A distributed source model-local autoregressive average (LAURA)-was used for the source localization. Sensitivity, specificity, and measurement of agreement (kappa) were determined based on the reference standard-the consensus conclusion of the multidisciplinary epilepsy surgery team. Predictive values were calculated from the surgical outcome of the operated patients. To estimate the clinical value of the ictal source analysis, we compared the likelihood ratios of concordant and discordant results. Source localization was performed blinded to the clinical data, and before the surgical decision. Reference standard was available for 33 patients. The ictal source localization had a sensitivity of 70% and a specificity of 76%. The mean measurement of agreement (kappa) was 0.61, corresponding to substantial agreement (95% confidence interval (CI) 0.38-0.84). Twenty patients underwent resective surgery. The positive predictive value (PPV) for seizure freedom was 92% and the negative predictive value (NPV) was 43%. The likelihood ratio was nine times higher for the concordant results, as compared with the discordant ones. Source localization of rhythmic ictal activity using a distributed source model (LAURA) for the ictal EEG signals selected with a standardized method

  10. Resident accuracy of joint line palpation using ultrasound verification.

    PubMed

    Rho, Monica E; Chu, Samuel K; Yang, Aaron; Hameed, Farah; Lin, Cindy Yuchin; Hurh, Peter J

    2014-10-01

    To determine the accuracy of knee and acromioclavicular (AC) joint line palpation in Physical Medicine and Rehabilitation (PM&R) residents using ultrasound (US) verification. Cohort study. PM&R residency program at an academic institution. Twenty-four PM&R residents participating in a musculoskeletal US course (7 PGY-2, 8 PGY-3, and 9 PGY4 residents). Twenty-four PM&R residents participating in an US course were asked to palpate the AC joint and lateral joint line of the knee in a female and male model before the start of the course. Once the presumed joint line was localized, the residents were asked to tape an 18-gauge, 1.5-inch, blunt-tip needle parallel to the joint line on the overlying skin. The accuracy of needle placement over the joint line was verified using US. US verification of correct needle placement over the joint line. Overall AC joint palpation accuracy was 16.7%, and knee lateral joint line palpation accuracy was 58.3%. Based on the resident level of education, using a value of P < .05, there were no statistically significant differences in the accuracy of joint line palpation. Residents in this study demonstrate poor accuracy of AC joint and lateral knee joint line identification by palpation, using US as the criterion standard for verification. There were no statistically significant differences in the accuracy rates of joint line palpation based on resident level of education. US may be a useful tool to use to advance the current methods of teaching the physical examination in medical education. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  11. Compact Intraoperative MRI: Stereotactic Accuracy and Future Directions.

    PubMed

    Markowitz, Daniel; Lin, Dishen; Salas, Sussan; Kohn, Nina; Schulder, Michael

    2017-01-01

    Intraoperative imaging must supply data that can be used for accurate stereotactic navigation. This information should be at least as accurate as that acquired from diagnostic imagers. The aim of this study was to compare the stereotactic accuracy of an updated compact intraoperative MRI (iMRI) device based on a 0.15-T magnet to standard surgical navigation on a 1.5-T diagnostic scan MRI and to navigation with an earlier model of the same system. The accuracy of each system was assessed using a water-filled phantom model of the brain. Data collected with the new system were compared to those obtained in a previous study assessing the older system. The accuracy of the new iMRI was measured against standard surgical navigation on a 1.5-T MRI using T1-weighted (W) images. The mean error with the iMRI using T1W images was lower than that based on images from the 1.5-T scan (1.24 vs. 2.43 mm). T2W images from the newer iMRI yielded a lower navigation error than those acquired with the prior model (1.28 vs. 3.15 mm). Improvements in magnet design can yield progressive increases in accuracy, validating the concept of compact, low-field iMRI. Avoiding the need for registration between image and surgical space increases navigation accuracy. © 2017 S. Karger AG, Basel.

  12. Accuracy of Cup Positioning With the Computed Tomography-Based Two-dimensional to Three-Dimensional Matched Navigation System: A Prospective, Randomized Controlled Study.

    PubMed

    Yamada, Kazuki; Endo, Hirosuke; Tetsunaga, Tomonori; Miyake, Takamasa; Sanki, Tomoaki; Ozaki, Toshifumi

    2018-01-01

    The accuracy of various navigation systems used for total hip arthroplasty has been described, but no publications reported the accuracy of cup orientation in computed tomography (CT)-based 2D-3D (two-dimensional to three-dimensional) matched navigation. In a prospective, randomized controlled study, 80 hips including 44 with developmental dysplasia of the hips were divided into a CT-based 2D-3D matched navigation group (2D-3D group) and a paired-point matched navigation group (PPM group). The accuracy of cup orientation (absolute difference between the intraoperative record and the postoperative measurement) was compared between groups. Additionally, multiple logistic regression analysis was performed to evaluate patient factors affecting the accuracy of cup orientation in each navigation. The accuracy of cup inclination was 2.5° ± 2.2° in the 2D-3D group and 4.6° ± 3.3° in the PPM group (P = .0016). The accuracy of cup anteversion was 2.3° ± 1.7° in the 2D-3D group and 4.4° ± 3.3° in the PPM group (P = .0009). In the PPM group, the presence of roof osteophytes decreased the accuracy of cup inclination (odds ratio 8.27, P = .0140) and the absolute value of pelvic tilt had a negative influence on the accuracy of cup anteversion (odds ratio 1.27, P = .0222). In the 2D-3D group, patient factors had no effect on the accuracy of cup orientation. The accuracy of cup positioning in CT-based 2D-3D matched navigation was better than in paired-point matched navigation, and was not affected by patient factors. It is a useful system for even severely deformed pelvises such as developmental dysplasia of the hips. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. Isotope ratios of trace elements in samples from human nutrition studies determined by TIMS and ICP-MS: precision and accuracy compared.

    PubMed

    Turnlund, Judith R; Keyes, William R

    2002-09-01

    Stable isotopes are used with increasing frequency to trace the metabolic fate of minerals in human nutrition studies. The precision of the analytical methods used must be sufficient to permit reliable measurement of low enrichments and the accuracy should permit comparisons between studies. Two methods most frequently used today are thermal ionization mass spectrometry (TIMS) and inductively coupled plasma mass spectrometry (ICP-MS). This study was conducted to compare the two methods. Multiple natural samples of copper, zinc, molybdenum, and magnesium were analyzed by both methods to compare their internal and external precision. Samples with a range of isotopic enrichments that were collected from human studies or prepared from standards were analyzed to compare their accuracy. TIMS was more precise and accurate than ICP-MS. However, the cost, ease, and speed of analysis were better for ICP-MS. Therefore, for most purposes, ICP-MS is the method of choice, but when the highest degrees of precision and accuracy are required and when enrichments are very low, TIMS is the method of choice.

  14. Reporting standards for studies of diagnostic test accuracy in dementia

    PubMed Central

    Noel-Storr, Anna H.; McCleery, Jenny M.; Richard, Edo; Ritchie, Craig W.; Flicker, Leon; Cullum, Sarah J.; Davis, Daniel; Quinn, Terence J.; Hyde, Chris; Rutjes, Anne W.S.; Smailagic, Nadja; Marcus, Sue; Black, Sandra; Blennow, Kaj; Brayne, Carol; Fiorivanti, Mario; Johnson, Julene K.; Köpke, Sascha; Schneider, Lon S.; Simmons, Andrew; Mattsson, Niklas; Zetterberg, Henrik; Bossuyt, Patrick M.M.; Wilcock, Gordon

    2014-01-01

    Objective: To provide guidance on standards for reporting studies of diagnostic test accuracy for dementia disorders. Methods: An international consensus process on reporting standards in dementia and cognitive impairment (STARDdem) was established, focusing on studies presenting data from which sensitivity and specificity were reported or could be derived. A working group led the initiative through 4 rounds of consensus work, using a modified Delphi process and culminating in a face-to-face consensus meeting in October 2012. The aim of this process was to agree on how best to supplement the generic standards of the STARD statement to enhance their utility and encourage their use in dementia research. Results: More than 200 comments were received during the wider consultation rounds. The areas at most risk of inadequate reporting were identified and a set of dementia-specific recommendations to supplement the STARD guidance were developed, including better reporting of patient selection, the reference standard used, avoidance of circularity, and reporting of test-retest reliability. Conclusion: STARDdem is an implementation of the STARD statement in which the original checklist is elaborated and supplemented with guidance pertinent to studies of cognitive disorders. Its adoption is expected to increase transparency, enable more effective evaluation of diagnostic tests in Alzheimer disease and dementia, contribute to greater adherence to methodologic standards, and advance the development of Alzheimer biomarkers. PMID:24944261

  15. Amplitude Integrated Electroencephalography Compared With Conventional Video EEG for Neonatal Seizure Detection: A Diagnostic Accuracy Study.

    PubMed

    Rakshasbhuvankar, Abhijeet; Rao, Shripada; Palumbo, Linda; Ghosh, Soumya; Nagarajan, Lakshmi

    2017-08-01

    This diagnostic accuracy study compared the accuracy of seizure detection by amplitude-integrated electroencephalography with the criterion standard conventional video EEG in term and near-term infants at risk of seizures. Simultaneous recording of amplitude-integrated EEG (2-channel amplitude-integrated EEG with raw trace) and video EEG was done for 24 hours for each infant. Amplitude-integrated EEG was interpreted by a neonatologist; video EEG was interpreted by a neurologist independently. Thirty-five infants were included in the analysis. In the 7 infants with seizures on video EEG, there were 169 seizure episodes on video EEG, of which only 57 were identified by amplitude-integrated EEG. Amplitude-integrated EEG had a sensitivity of 33.7% for individual seizure detection. Amplitude-integrated EEG had an 86% sensitivity for detection of babies with seizures; however, it was nonspecific, in that 50% of infants with seizures detected by amplitude-integrated EEG did not have true seizures by video EEG. In conclusion, our study suggests that amplitude-integrated EEG is a poor screening tool for neonatal seizures.

  16. Accuracy of the Omron HEM-705 CP for blood pressure measurement in large epidemiologic studies.

    PubMed

    Vera-Cala, Lina M; Orostegui, Myriam; Valencia-Angel, Laura I; López, Nahyr; Bautista, Leonelo E

    2011-05-01

    Accurate measurement of blood pressure is of utmost importance in hypertension research. In the context of epidemiologic and clinical studies, oscillometric devices offer important advantages to overcome some of the limitations of the auscultatory method. Even though their accuracy has been evaluated in multiple studies in the clinical setting, there is little evidence of their performance in large epidemiologic studies. We evaluated the accuracy of the Omron HEM-705-CP, an automatic device for blood pressure (BP) measurement, as compared to the standard auscultatory method with a mercury sphygmomanometer in a large cohort study. We made three auscultatory measurements, followed by two measurements with the Omron device in 1,084 subjects. Bias was estimated as the average of the two Omron minus the average of the last two auscultatory measurements, with its corresponding 95% limits of agreement (LA). The Omron overestimated systolic blood pressure (SBP) by 1.8 mmHg (LA:-10.1, 13.7) and underestimated diastolic blood pressure (DBP) by 1.6 mmHg (LA:-12.3, 9.2). Bias was significantly larger in men. Bias in SBP increased with age and decreased with BP level, while bias in DBP decreased with age and increased with BP level. The sensitivity and specificity of the Omron to detect hypertension were 88.2% and 98.6%, respectively. Minimum bias in the estimates of the effects of several factors resulted from the use of Omron measurements. Our results showed that the Omron HEM-705-CP could be used for measuring BP in large epidemiology studies without compromising study validity or precision.

  17. Additional studies of forest classification accuracy as influenced by multispectral scanner spatial resolution

    NASA Technical Reports Server (NTRS)

    Sadowski, F. E.; Sarno, J. E.

    1976-01-01

    First, an analysis of forest feature signatures was used to help explain the large variation in classification accuracy that can occur among individual forest features for any one case of spatial resolution and the inconsistent changes in classification accuracy that were demonstrated among features as spatial resolution was degraded. Second, the classification rejection threshold was varied in an effort to reduce the large proportion of unclassified resolution elements that previously appeared in the processing of coarse resolution data when a constant rejection threshold was used for all cases of spatial resolution. For the signature analysis, two-channel ellipse plots showing the feature signature distributions for several cases of spatial resolution indicated that the capability of signatures to correctly identify their respective features is dependent on the amount of statistical overlap among signatures. Reductions in signature variance that occur in data of degraded spatial resolution may not necessarily decrease the amount of statistical overlap among signatures having large variance and small mean separations. Features classified by such signatures may thus continue to have similar amounts of misclassified elements in coarser resolution data, and thus, not necessarily improve in classification accuracy.

  18. Shoulder-Mounted Robot for MRI-guided arthrography: Accuracy and mounting study.

    PubMed

    Monfaredi, R; Wilson, E; Sze, R; Sharma, K; Azizi, B; Iordachita, I; Cleary, K

    2015-08-01

    A new version of our compact and lightweight patient-mounted MRI-compatible 4 degree-of-freedom (DOF) robot for MRI-guided arthrography procedures is introduced. This robot could convert the traditional two-stage arthrography procedure (fluoroscopy-guided needle insertion followed by a diagnostic MRI scan) to a one-stage procedure, all in the MRI suite. The results of a recent accuracy study are reported. A new mounting technique is proposed and the mounting stability is investigated using optical and electromagnetic tracking on an anthropomorphic phantom. Five volunteer subjects including 2 radiologists were asked to conduct needle insertion in 4 different random positions and orientations within the robot's workspace and the displacement of the base of the robot was investigated during robot motion and needle insertion. Experimental results show that the proposed mounting method is stable and promising for clinical application.

  19. Influence of lidar, Landsat imagery, disturbance history, plot location accuracy, and plot size on accuracy of imputation maps of forest composition and structure

    Treesearch

    Harold S.J. Zald; Janet L. Ohmann; Heather M. Roberts; Matthew J. Gregory; Emilie B. Henderson; Robert J. McGaughey; Justin Braaten

    2014-01-01

    This study investigated how lidar-derived vegetation indices, disturbance history from Landsat time series (LTS) imagery, plot location accuracy, and plot size influenced accuracy of statistical spatial models (nearest-neighbor imputation maps) of forest vegetation composition and structure. Nearest-neighbor (NN) imputation maps were developed for 539,000 ha in the...

  20. Small Body Landing Accuracy Using In-Situ Navigation

    NASA Technical Reports Server (NTRS)

    Bhaskaran, Shyam; Nandi, Sumita; Broschart, Stephen; Wallace, Mark; Olson, Corwin; Cangahuala, L. Alberto

    2011-01-01

    Spacecraft landings on small bodies (asteroids and comets) can require target accuracies too stringent to be met using ground-based navigation alone, especially if specific landing site requirements must be met for safety or to meet science goals. In-situ optical observations coupled with onboard navigation processing can meet the tighter accuracy requirements to enable such missions. Recent developments in deep space navigation capability include a self-contained autonomous navigation system (used in flight on three missions) and a landmark tracking system (used experimentally on the Japanese Hayabusa mission). The merging of these two technologies forms a methodology to perform autonomous onboard navigation around small bodies. This paper presents an overview of these systems, as well as the results from Monte Carlo studies to quantify the achievable landing accuracies by using these methods. Sensitivity of the results to variations in spacecraft maneuver execution error, attitude control accuracy and unmodeled forces are examined. Cases for two bodies, a small asteroid and on a mid-size comet, are presented.

  1. Accuracy in inference of nursing diagnoses in heart failure patients.

    PubMed

    Pereira, Juliana de Melo Vellozo; Cavalcanti, Ana Carla Dantas; Lopes, Marcos Venícios de Oliveira; da Silva, Valéria Gonçalves; de Souza, Rosana Oliveira; Gonçalves, Ludmila Cuzatis

    2015-01-01

    Heart failure (HF) is a common cause of hospitalization and requires accuracy in clinical judgment and appropriate nursing diagnoses. to determine the accuracy of nursing diagnoses of fatigue, intolerance to activity and decreased cardiac output in hospitalized HF patients. descriptive study applied to nurses with experience in NANDA-I and/or HF nursing diagnoses. Evaluation and accuracy were determined by calculating efficacy (E), false negative (FN), false positive (FP) and trend (T) measures. Nurses who showed acceptable inspection for two diagnoses were selected. the nursing diagnosis of fatigue was the most commonly mistaken diagnosis identified by the nursing evaluators. the search for improving diagnostic accuracy reaffirms the need for continuous and specific training to improve the diagnosis capability of nurses. the training allowed the exercise of clinical judgment and better accuracy of nurses.

  2. Measuring Diagnoses: ICD Code Accuracy

    PubMed Central

    O'Malley, Kimberly J; Cook, Karon F; Price, Matt D; Wildes, Kimberly Raiford; Hurdle, John F; Ashton, Carol M

    2005-01-01

    Objective To examine potential sources of errors at each step of the described inpatient International Classification of Diseases (ICD) coding process. Data Sources/Study Setting The use of disease codes from the ICD has expanded from classifying morbidity and mortality information for statistical purposes to diverse sets of applications in research, health care policy, and health care finance. By describing a brief history of ICD coding, detailing the process for assigning codes, identifying where errors can be introduced into the process, and reviewing methods for examining code accuracy, we help code users more systematically evaluate code accuracy for their particular applications. Study Design/Methods We summarize the inpatient ICD diagnostic coding process from patient admission to diagnostic code assignment. We examine potential sources of errors at each step and offer code users a tool for systematically evaluating code accuracy. Principle Findings Main error sources along the “patient trajectory” include amount and quality of information at admission, communication among patients and providers, the clinician's knowledge and experience with the illness, and the clinician's attention to detail. Main error sources along the “paper trail” include variance in the electronic and written records, coder training and experience, facility quality-control efforts, and unintentional and intentional coder errors, such as misspecification, unbundling, and upcoding. Conclusions By clearly specifying the code assignment process and heightening their awareness of potential error sources, code users can better evaluate the applicability and limitations of codes for their particular situations. ICD codes can then be used in the most appropriate ways. PMID:16178999

  3. [Study on high accuracy detection of multi-component gas in oil-immerse power transformer].

    PubMed

    Fan, Jie; Chen, Xiao; Huang, Qi-Feng; Zhou, Yu; Chen, Gang

    2013-12-01

    In order to solve the problem of low accuracy and mutual interference in multi-component gas detection, a kind of multi-component gas detection network with high accuracy was designed. A semiconductor laser with narrow bandwidth was utilized as light source and a novel long-path gas cell was also used in this system. By taking the single sine signal to modulate the spectrum of laser and using space division multiplexing (SDM) and time division multiplexing (TDM) technique, the detection of multi-component gas was achieved. The experiments indicate that the linearity relevance coefficient is 0. 99 and the measurement relative error is less than 4%. The system dynamic response time is less than 15 s, by filling a volume of multi-component gas into the gas cell gradually. The system has advantages of high accuracy and quick response, which can be used in the fault gas on-line monitoring for power transformers in real time.

  4. A pilot study of the effects of interview content, retention interval, and grade on accuracy of dietary information from children

    PubMed Central

    Baxter, Suzanne Domel; Hitchcock, David B; Guinn, Caroline H; Royer, Julie A; Wilson, Dawn K; Pate, Russell R; McIver, Kerry L; Dowda, Marsha

    2013-01-01

    Objective Investigate differences in dietary recall accuracy by interview content (diet-only; diet-and-physical-activity), retention interval (same-day; previous-day), and grade (3rd; 5th). Methods Thirty-two children observed eating school-provided meals and interviewed once each; interview content and retention interval randomly assigned. Multivariate analysis of variance on rates for omissions (foods observed but unreported) and intrusions (foods reported but unobserved); independent variables—interview content, retention interval, grade. Results Accuracy differed by retention interval (P = .05; better for same-day [omission rate, intrusion rate: 28%, 20%] than previous-day [54%, 45%]) but not interview content (P > .48; diet-only: 41%, 33%; diet-and-physical-activity: 41%, 33%) or grade (P > .27; 3rd: 48%, 42%; 5th: 34%, 24%). Conclusions and Implications Although the small sample limits firm conclusions, results provide evidence-based direction to enhance accuracy; specifically, to shorten the retention interval. Larger validation studies need to investigate the combined effect of interview content, retention interval, and grade on accuracy. PMID:23562487

  5. Clinical acceptance and accuracy assessment of spinal implants guided with SpineAssist surgical robot: retrospective study.

    PubMed

    Devito, Dennis P; Kaplan, Leon; Dietl, Rupert; Pfeiffer, Michael; Horne, Dale; Silberstein, Boris; Hardenbrook, Mitchell; Kiriyanthan, George; Barzilay, Yair; Bruskin, Alexander; Sackerer, Dieter; Alexandrovsky, Vitali; Stüer, Carsten; Burger, Ralf; Maeurer, Johannes; Donald, Gordon D; Gordon, Donald G; Schoenmayr, Robert; Friedlander, Alon; Knoller, Nachshon; Schmieder, Kirsten; Pechlivanis, Ioannis; Kim, In-Se; Meyer, Bernhard; Shoham, Moshe

    2010-11-15

    Retrospective, multicenter study of robotically-guided spinal implant insertions. Clinical acceptance of the implants was assessed by intraoperative radiograph, and when available, postoperative computed tomography (CT) scans were used to determine placement accuracy. To verify the clinical acceptance and accuracy of robotically-guided spinal implants and compare to those of unguided free-hand procedures. SpineAssist surgical robot has been used to guide implants and guide-wires to predefined locations in the spine. SpineAssist which, to the best of the authors' knowledge, is currently the sole robot providing surgical assistance in positioning tools in the spine, guided over 840 cases in 14 hospitals, between June 2005 and June 2009. Clinical acceptance of 3271 pedicle screws and guide-wires inserted in 635 reported cases was assessed by intraoperative fluoroscopy, where placement accuracy of 646 pedicle screws inserted in 139 patients was measured using postoperative CT scans. Screw placements were found to be clinically acceptable in 98% of the cases when intraoperatively assessed by fluoroscopic images. Measurements derived from postoperative CT scans demonstrated that 98.3% of the screws fell within the safe zone, where 89.3% were completely within the pedicle and 9% breached the pedicle by up to 2 mm. The remaining 1.4% of the screws breached between 2 and 4 mm, while only 2 screws (0.3%) deviated by more than 4 mm from the pedicle wall. Neurologic deficits were observed in 4 cases yet, following revisions, no permanent nerve damage was encountered, in contrast to the 0.6% to 5% of neurologic damage reported in the literature. SpineAssist offers enhanced performance in spinal surgery when compared to free-hand surgeries, by increasing placement accuracy and reducing neurologic risks. In addition, 49% of the cases reported herein used a percutaneous approach, highlighting the contribution of SpineAssist in procedures without anatomic landmarks.

  6. Accuracy of the unified approach in maternally influenced traits--illustrated by a simulation study in the honey bee (Apis mellifera).

    PubMed

    Gupta, Pooja; Reinsch, Norbert; Spötter, Andreas; Conrad, Tim; Bienefeld, Kaspar

    2013-05-06

    The honey bee is an economically important species. With a rapid decline of the honey bee population, it is necessary to implement an improved genetic evaluation methodology. In this study, we investigated the applicability of the unified approach and its impact on the accuracy of estimation of breeding values for maternally influenced traits on a simulated dataset for the honey bee. Due to the limitation to the number of individuals that can be genotyped in a honey bee population, the unified approach can be an efficient strategy to increase the genetic gain and to provide a more accurate estimation of breeding values. We calculated the accuracy of estimated breeding values for two evaluation approaches, the unified approach and the traditional pedigree based approach. We analyzed the effects of different heritabilities as well as genetic correlation between direct and maternal effects on the accuracy of estimation of direct, maternal and overall breeding values (sum of maternal and direct breeding values). The genetic and reproductive biology of the honey bee was accounted for by taking into consideration characteristics such as colony structure, uncertain paternity, overlapping generations and polyandry. In addition, we used a modified numerator relationship matrix and a realistic genome for the honey bee. For all values of heritability and correlation, the accuracy of overall estimated breeding values increased significantly with the unified approach. The increase in accuracy was always higher for the case when there was no correlation as compared to the case where a negative correlation existed between maternal and direct effects. Our study shows that the unified approach is a useful methodology for genetic evaluation in honey bees, and can contribute immensely to the improvement of traits of apicultural interest such as resistance to Varroa or production and behavioural traits. In particular, the study is of great interest for cases where negative correlation

  7. Accuracy of the unified approach in maternally influenced traits - illustrated by a simulation study in the honey bee (Apis mellifera)

    PubMed Central

    2013-01-01

    Background The honey bee is an economically important species. With a rapid decline of the honey bee population, it is necessary to implement an improved genetic evaluation methodology. In this study, we investigated the applicability of the unified approach and its impact on the accuracy of estimation of breeding values for maternally influenced traits on a simulated dataset for the honey bee. Due to the limitation to the number of individuals that can be genotyped in a honey bee population, the unified approach can be an efficient strategy to increase the genetic gain and to provide a more accurate estimation of breeding values. We calculated the accuracy of estimated breeding values for two evaluation approaches, the unified approach and the traditional pedigree based approach. We analyzed the effects of different heritabilities as well as genetic correlation between direct and maternal effects on the accuracy of estimation of direct, maternal and overall breeding values (sum of maternal and direct breeding values). The genetic and reproductive biology of the honey bee was accounted for by taking into consideration characteristics such as colony structure, uncertain paternity, overlapping generations and polyandry. In addition, we used a modified numerator relationship matrix and a realistic genome for the honey bee. Results For all values of heritability and correlation, the accuracy of overall estimated breeding values increased significantly with the unified approach. The increase in accuracy was always higher for the case when there was no correlation as compared to the case where a negative correlation existed between maternal and direct effects. Conclusions Our study shows that the unified approach is a useful methodology for genetic evaluation in honey bees, and can contribute immensely to the improvement of traits of apicultural interest such as resistance to Varroa or production and behavioural traits. In particular, the study is of great interest for

  8. Influence of outliers on accuracy estimation in genomic prediction in plant breeding.

    PubMed

    Estaghvirou, Sidi Boubacar Ould; Ogutu, Joseph O; Piepho, Hans-Peter

    2014-10-01

    Outliers often pose problems in analyses of data in plant breeding, but their influence on the performance of methods for estimating predictive accuracy in genomic prediction studies has not yet been evaluated. Here, we evaluate the influence of outliers on the performance of methods for accuracy estimation in genomic prediction studies using simulation. We simulated 1000 datasets for each of 10 scenarios to evaluate the influence of outliers on the performance of seven methods for estimating accuracy. These scenarios are defined by the number of genotypes, marker effect variance, and magnitude of outliers. To mimic outliers, we added to one observation in each simulated dataset, in turn, 5-, 8-, and 10-times the error SD used to simulate small and large phenotypic datasets. The effect of outliers on accuracy estimation was evaluated by comparing deviations in the estimated and true accuracies for datasets with and without outliers. Outliers adversely influenced accuracy estimation, more so at small values of genetic variance or number of genotypes. A method for estimating heritability and predictive accuracy in plant breeding and another used to estimate accuracy in animal breeding were the most accurate and resistant to outliers across all scenarios and are therefore preferable for accuracy estimation in genomic prediction studies. The performances of the other five methods that use cross-validation were less consistent and varied widely across scenarios. The computing time for the methods increased as the size of outliers and sample size increased and the genetic variance decreased. Copyright © 2014 Ould Estaghvirou et al.

  9. Accuracy of VarioGuide Frameless Stereotactic System Against Frame-Based Stereotaxy: Prospective, Randomized, Single-Center Study.

    PubMed

    Bradac, Ondrej; Steklacova, Anna; Nebrenska, Katerina; Vrana, Jiri; de Lacy, Patricia; Benes, Vladimir

    2017-08-01

    Frameless stereotactic brain biopsy systems are widely used today. VarioGuide (VG) is a relatively novel frameless system. Its accuracy was studied in a laboratory setting but has not yet been studied in the clinical setting. The purpose of this study was to determine its accuracy and diagnostic yield and to compare this with frame-based (FB) stereotaxy. Overall, 53 patients (33 males and 20 females, 60 ± 15 years old) were enrolled into this prospective, randomized, single-center study. Twenty-six patients were randomized into the FB group and 27 patients into the VG group. Real trajectory was pointed on intraoperative magnetic resonance. The distance of the targets and angle deviation between the planned and real trajectories were computed. The overall discomfort of the patient was subjectively assessed by the visual analog scale score. The median lesion volume was 5 mL (interquartile range [IQR]: 2-16 mL) (FB) and 16 mL (IQR: 2-27 mL) (VG), P = 0.133. The mean distance of the targets was 2.7 ± 1.1 mm (FB) and 2.9 ± 1.3 mm (VG), P = 0.456. Mean angle deviation was 2.6 ± 1.3 deg (FB) and 3.5 ± 2.1 deg (VG), P = 0.074. Diagnostic yield was 93% (25/27) in VG and 96% (25/26) in FB, P = 1.000. Mean operating time was 47 ± 26 minutes (FB) and 59 ± 31 minutes (VG), P = 0.140. One minor bleeding was encountered in the VG group. Overall patient discomfort was significantly higher in the FB group (visual analog scale score 2.5 ± 2.1 vs. 1.2 ± 0.6, P = 0,004). The VG system proved to be comparable in terms of the trajectory accuracy, rate of complications and diagnostic yield compared with the "gold standard" represented by the traditional FB stereotaxy for patients undergoing brain biopsy. VG is also better accepted by patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. An observational study of the accuracy and completeness of an anesthesia information management system: recommendations for documentation system changes.

    PubMed

    Wilbanks, Bryan A; Moss, Jacqueline A; Berner, Eta S

    2013-08-01

    Anesthesia information management systems must often be tailored to fit the environment in which they are implemented. Extensive customization necessitates that systems be analyzed for both accuracy and completeness of documentation design to ensure that the final record is a true representation of practice. The purpose of this study was to determine the accuracy of a recently installed system in the capture of key perianesthesia data. This study used an observational design and was conducted using a convenience sample of nurse anesthetists. Observational data of the nurse anesthetists'delivery of anesthesia care were collected using a touch-screen tablet computer utilizing an Access database customized observational data collection tool. A questionnaire was also administered to these nurse anesthetists to assess perceived accuracy, completeness, and satisfaction with the electronic documentation system. The major sources of data not documented in the system were anesthesiologist presence (20%) and placement of intravenous lines (20%). The major sources of inaccuracies in documentation were gas flow rates (45%), medication administration times (30%), and documentation of neuromuscular function testing (20%)-all of the sources of inaccuracies were related to the use of charting templates that were not altered to reflect the actual interventions performed.

  11. The accuracy of prehospital diagnosis of acute cerebrovascular accidents: an observational study.

    PubMed

    Karliński, Michał; Gluszkiewicz, Marcin; Członkowska, Anna

    2015-06-19

    Time to treatment is the key factor in stroke care. Although the initial medical assessment is usually made by a non-neurologist or a paramedic, it should ensure correct identification of all acute cerebrovascular accidents (CVAs). Our aim was to evaluate the accuracy of the physician-made prehospital diagnosis of acute CVA in patients referred directly to the neurological emergency department (ED), and to identify conditions mimicking CVAs. This observational study included consecutive patients referred to our neurological ED by emergency physicians with a suspicion of CVA (acute stroke, transient ischemic attack (TIA) or a syndrome-based diagnosis) during 12 months. Referrals were considered correct if the prehospital diagnosis of CVA proved to be stroke or TIA. The prehospital diagnosis of CVA was correct in 360 of 570 cases. Its positive predictive value ranged from 100% for the syndrome-based diagnosis, through 70% for stroke, to 34% for TIA. Misdiagnoses were less frequent among ambulance physicians compared to primary care and outpatient physicians (33% vs. 52%, p < 0.001). The most frequent mimics were vertigo (19%), electrolyte and metabolic disturbances (12%), seizures (11%), cardiovascular disorders (10%), blood hypertension (8%) and brain tumors (5%). Additionally, 6% of all admitted CVA cases were referred with prehospital diagnoses other than CVA. Emergency physicians appear to be sensitive in diagnosing CVAs but their overall accuracy does not seem high. They tend to overuse the diagnosis of TIA. Constant education and adoption of stroke screening scales may be beneficial for emergency care systems based both on physicians and on paramedics.

  12. The accuracy of prehospital diagnosis of acute cerebrovascular accidents: an observational study

    PubMed Central

    Gluszkiewicz, Marcin; Członkowska, Anna

    2015-01-01

    Introduction Time to treatment is the key factor in stroke care. Although the initial medical assessment is usually made by a non-neurologist or a paramedic, it should ensure correct identification of all acute cerebrovascular accidents (CVAs). Our aim was to evaluate the accuracy of the physician-made prehospital diagnosis of acute CVA in patients referred directly to the neurological emergency department (ED), and to identify conditions mimicking CVAs. Material and methods This observational study included consecutive patients referred to our neurological ED by emergency physicians with a suspicion of CVA (acute stroke, transient ischemic attack (TIA) or a syndrome-based diagnosis) during 12 months. Referrals were considered correct if the prehospital diagnosis of CVA proved to be stroke or TIA. Results The prehospital diagnosis of CVA was correct in 360 of 570 cases. Its positive predictive value ranged from 100% for the syndrome-based diagnosis, through 70% for stroke, to 34% for TIA. Misdiagnoses were less frequent among ambulance physicians compared to primary care and outpatient physicians (33% vs. 52%, p < 0.001). The most frequent mimics were vertigo (19%), electrolyte and metabolic disturbances (12%), seizures (11%), cardiovascular disorders (10%), blood hypertension (8%) and brain tumors (5%). Additionally, 6% of all admitted CVA cases were referred with prehospital diagnoses other than CVA. Conclusions Emergency physicians appear to be sensitive in diagnosing CVAs but their overall accuracy does not seem high. They tend to overuse the diagnosis of TIA. Constant education and adoption of stroke screening scales may be beneficial for emergency care systems based both on physicians and on paramedics. PMID:26170845

  13. Vocal Accuracy and Neural Plasticity Following Micromelody-Discrimination Training

    PubMed Central

    Zarate, Jean Mary; Delhommeau, Karine; Wood, Sean; Zatorre, Robert J.

    2010-01-01

    Background Recent behavioral studies report correlational evidence to suggest that non-musicians with good pitch discrimination sing more accurately than those with poorer auditory skills. However, other studies have reported a dissociation between perceptual and vocal production skills. In order to elucidate the relationship between auditory discrimination skills and vocal accuracy, we administered an auditory-discrimination training paradigm to a group of non-musicians to determine whether training-enhanced auditory discrimination would specifically result in improved vocal accuracy. Methodology/Principal Findings We utilized micromelodies (i.e., melodies with seven different interval scales, each smaller than a semitone) as the main stimuli for auditory discrimination training and testing, and we used single-note and melodic singing tasks to assess vocal accuracy in two groups of non-musicians (experimental and control). To determine if any training-induced improvements in vocal accuracy would be accompanied by related modulations in cortical activity during singing, the experimental group of non-musicians also performed the singing tasks while undergoing functional magnetic resonance imaging (fMRI). Following training, the experimental group exhibited significant enhancements in micromelody discrimination compared to controls. However, we did not observe a correlated improvement in vocal accuracy during single-note or melodic singing, nor did we detect any training-induced changes in activity within brain regions associated with singing. Conclusions/Significance Given the observations from our auditory training regimen, we therefore conclude that perceptual discrimination training alone is not sufficient to improve vocal accuracy in non-musicians, supporting the suggested dissociation between auditory perception and vocal production. PMID:20567521

  14. Adults with suspected central nervous system infection: A prospective study of diagnostic accuracy.

    PubMed

    Khatib, Ula; van de Beek, Diederik; Lees, John A; Brouwer, Matthijs C

    2017-01-01

    To study the diagnostic accuracy of clinical and laboratory features in the diagnosis of central nervous system (CNS) infection and bacterial meningitis. We included consecutive adult episodes with suspected CNS infection who underwent cerebrospinal fluid (CSF) examination. The reference standard was the diagnosis classified into five categories: 1) CNS infection; 2) CNS inflammation without infection; 3) other neurological disorder; 4) non-neurological infection; and 5) other systemic disorder. Between 2012 and 2015, 363 episodes of suspected CNS infection were included. CSF examination showed leucocyte count >5/mm 3 in 47% of episodes. Overall, 89 of 363 episodes were categorized as CNS infection (25%; most commonly viral meningitis [7%], bacterial meningitis [7%], and viral encephalitis [4%]), 36 (10%) episodes as CNS inflammatory disorder, 111 (31%) as systemic infection, in 119 (33%) as other neurological disorder, and 8 (2%) as other systemic disorders. Diagnostic accuracy of individual clinical characteristics and blood tests for the diagnosis of CNS infection or bacterial meningitis was low. CSF leucocytosis differentiated best between bacterial meningitis and other diagnoses (area under the curve [AUC] 0.95) or any neurological infection versus other diagnoses (AUC 0.93). Clinical characteristics fail to differentiate between neurological infections and other diagnoses, and CSF analysis is the main contributor to the final diagnosis. Copyright © 2016 The British Infection Association. Published by Elsevier Ltd. All rights reserved.

  15. Ultrasound for Distal Forearm Fracture: A Systematic Review and Diagnostic Meta-Analysis

    PubMed Central

    Douma-den Hamer, Djoke; Blanker, Marco H.; Edens, Mireille A.; Buijteweg, Lonneke N.; Boomsma, Martijn F.; van Helden, Sven H.; Mauritz, Gert-Jan

    2016-01-01

    Study Objective To determine the diagnostic accuracy of ultrasound for detecting distal forearm fractures. Methods A systematic review and diagnostic meta-analysis was performed according to the PRISMA statement. We searched MEDLINE, Web of Science and the Cochrane Library from inception to September 2015. All prospective studies of the diagnostic accuracy of ultrasound versus radiography as the reference standard were included. We excluded studies with a retrospective design and those with evidence of verification bias. We assessed the methodological quality of the included studies with the QUADAS-2 tool. We performed a meta-analysis of studies evaluating ultrasound to calculate the pooled sensitivity and specificity with 95% confidence intervals (CI95%) using a bivariate model with random effects. Subgroup and sensitivity analysis were used to examine the effect of methodological differences and other study characteristics. Results Out of 867 publications we included 16 studies with 1,204 patients and 641 fractures. The pooled test characteristics for ultrasound were: sensitivity 97% (CI95% 93–99%), specificity 95% (CI95% 89–98%), positive likelihood ratio (LR) 20.0 (8.5–47.2) and negative LR 0.03 (0.01–0.08). The corresponding pooled diagnostic odds ratio (DOR) was 667 (142–3,133). Apparent differences were shown for method of viewing, with the 6-view method showing higher specificity, positive LR, and DOR, compared to the 4-view method. Conclusion The present meta-analysis showed that ultrasound has a high accuracy for the diagnosis of distal forearm fractures in children when used by proper viewing method. Based on this, ultrasound should be considered a reliable alternative, which has the advantages of being radiation free. PMID:27196439

  16. High accuracy differential pressure measurements using fluid-filled catheters - A feasibility study in compliant tubes.

    PubMed

    Rotman, Oren Moshe; Weiss, Dar; Zaretsky, Uri; Shitzer, Avraham; Einav, Shmuel

    2015-09-18

    High accuracy differential pressure measurements are required in various biomedical and medical applications, such as in fluid-dynamic test systems, or in the cath-lab. Differential pressure measurements using fluid-filled catheters are relatively inexpensive, yet may be subjected to common mode pressure errors (CMP), which can significantly reduce the measurement accuracy. Recently, a novel correction method for high accuracy differential pressure measurements was presented, and was shown to effectively remove CMP distortions from measurements acquired in rigid tubes. The purpose of the present study was to test the feasibility of this correction method inside compliant tubes, which effectively simulate arteries. Two tubes with varying compliance were tested under dynamic flow and pressure conditions to cover the physiological range of radial distensibility in coronary arteries. A third, compliant model, with a 70% stenosis severity was additionally tested. Differential pressure measurements were acquired over a 3 cm tube length using a fluid-filled double-lumen catheter, and were corrected using the proposed CMP correction method. Validation of the corrected differential pressure signals was performed by comparison to differential pressure recordings taken via a direct connection to the compliant tubes, and by comparison to predicted differential pressure readings of matching fluid-structure interaction (FSI) computational simulations. The results show excellent agreement between the experimentally acquired and computationally determined differential pressure signals. This validates the application of the CMP correction method in compliant tubes of the physiological range for up to intermediate size stenosis severity of 70%. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Daily modulation of the speed-accuracy trade-off.

    PubMed

    Gueugneau, Nicolas; Pozzo, Thierry; Darlot, Christian; Papaxanthis, Charalambos

    2017-07-25

    Goal-oriented arm movements are characterized by a balance between speed and accuracy. The relation between speed and accuracy has been formalized by Fitts' law and predicts a linear increase in movement duration with task constraints. Up to now this relation has been investigated on a short-time scale only, that is during a single experimental session, although chronobiological studies report that the motor system is shaped by circadian rhythms. Here, we examine whether the speed-accuracy trade-off could vary during the day. Healthy adults carried out arm-pointing movements as accurately and fast as possible toward targets of different sizes at various hours of the day, and variations in Fitts' law parameters were scrutinized. To investigate whether the potential modulation of the speed-accuracy trade-off has peripheral and/or central origins, a motor imagery paradigm was used as well. Results indicated a daily (circadian-like) variation for the durations of both executed and mentally simulated movements, in strictly controlled accuracy conditions. While Fitts' law was held for the whole sessions of the day, the slope of the relation between movement duration and task difficulty expressed a clear modulation, with the lowest values in the afternoon. This variation of the speed-accuracy trade-off in executed and mental movements suggests that, beyond execution parameters, motor planning mechanisms are modulated during the day. Daily update of forward models is discussed as a potential mechanism. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Optimizing Tsunami Forecast Model Accuracy

    NASA Astrophysics Data System (ADS)

    Whitmore, P.; Nyland, D. L.; Huang, P. Y.

    2015-12-01

    Recent tsunamis provide a means to determine the accuracy that can be expected of real-time tsunami forecast models. Forecast accuracy using two different tsunami forecast models are compared for seven events since 2006 based on both real-time application and optimized, after-the-fact "forecasts". Lessons learned by comparing the forecast accuracy determined during an event to modified applications of the models after-the-fact provide improved methods for real-time forecasting for future events. Variables such as source definition, data assimilation, and model scaling factors are examined to optimize forecast accuracy. Forecast accuracy is also compared for direct forward modeling based on earthquake source parameters versus accuracy obtained by assimilating sea level data into the forecast model. Results show that including assimilated sea level data into the models increases accuracy by approximately 15% for the events examined.

  19. TMS combined with EEG in genetic generalized epilepsy: A phase II diagnostic accuracy study.

    PubMed

    Kimiskidis, Vasilios K; Tsimpiris, Alkiviadis; Ryvlin, Philippe; Kalviainen, Reetta; Koutroumanidis, Michalis; Valentin, Antonio; Laskaris, Nikolaos; Kugiumtzis, Dimitris

    2017-02-01

    (A) To develop a TMS-EEG stimulation and data analysis protocol in genetic generalized epilepsy (GGE). (B) To investigate the diagnostic accuracy of TMS-EEG in GGE. Pilot experiments resulted in the development and optimization of a paired-pulse TMS-EEG protocol at rest, during hyperventilation (HV), and post-HV combined with multi-level data analysis. This protocol was applied in 11 controls (C) and 25 GGE patients (P), further dichotomized into responders to antiepileptic drugs (R, n=13) and non-responders (n-R, n=12).Features (n=57) extracted from TMS-EEG responses after multi-level analysis were given to a feature selection scheme and a Bayesian classifier, and the accuracy of assigning participants into the classes P-C and R-nR was computed. On the basis of the optimal feature subset, the cross-validated accuracy of TMS-EEG for the classification P-C was 0.86 at rest, 0.81 during HV and 0.92 at post-HV, whereas for R-nR the corresponding figures are 0.80, 0.78 and 0.65, respectively. Applying a fusion approach on all conditions resulted in an accuracy of 0.84 for the classification P-C and 0.76 for the classification R-nR. TMS-EEG can be used for diagnostic purposes and for assessing the response to antiepileptic drugs. TMS-EEG holds significant diagnostic potential in GGE. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  20. Diagnostic accuracy of non-contrast abdominal CT scans performed as follow-up for patients with an established cancer diagnosis: a retrospective study.

    PubMed

    Semaan, Hassan; Bazerbashi, Mohamad F; Siesel, Geoffrey; Aldinger, Paul; Obri, Tawfik

    2018-03-01

    To determine the accuracy and non-detection rate of cancer related findings (CRFs) on follow-up non-contrast-enhanced CT (NECT) versus contrast-enhanced CT (CECT) images of the abdomen in patients with a known cancer diagnosis. A retrospective review of 352 consecutive CTs of the abdomen performed with and without IV contrast between March 2010 and October 2014 for follow-up of cancer was included. Two radiologists independently assessed the NECT portions of the studies. The reader was provided the primary cancer diagnosis and access to the most recent prior NECT study. The accuracy and non-detection rates were determined by comparing our results to the archived reports as a gold standard. A total of 383 CRFs were found in the archived reports of the 352 abdominal CTs. The average non-detection rate for the NECTs compared to the CECTs was 3.0% (11.5/383) with an accuracy of 97.0% (371.5/383) in identifying CRFs. The most common findings missed were vascular thrombosis with a non-detection rate of 100%. The accuracy for non-vascular CRFs was 99.1%. Follow-up NECT abdomen studies are highly accurate in the detection of CRFs in patients with an established cancer diagnosis, except in cases where vascular involvement is suspected.

  1. Design and preliminary accuracy studies of an MRI-guided transrectal prostate intervention system.

    PubMed

    Krieger, Axel; Csoma, Csaba; Iordachital, Iulian I; Guion, Peter; Singh, Anurag K; Fichtinger, Gabor; Whitcomb, Louis L

    2007-01-01

    This paper reports a novel system for magnetic resonance imaging (MRI) guided transrectal prostate interventions, such as needle biopsy, fiducial marker placement, and therapy delivery. The system utilizes a hybrid tracking method, comprised of passive fiducial tracking for initial registration and subsequent incremental motion measurement along the degrees of freedom using fiber-optical encoders and mechanical scales. Targeting accuracy of the system is evaluated in prostate phantom experiments. Achieved targeting accuracy and procedure times were found to compare favorably with existing systems using passive and active tracking methods. Moreover, the portable design of the system using only standard MRI image sequences and minimal custom scanner interfacing allows the system to be easily used on different MRI scanners.

  2. Improving the accuracy of birth notification data: lessons from the Birth to Ten study

    PubMed Central

    Ellison, GTH; Richter, LM; de Wet, T; Harris, HE; Griesel, RD; McIntyre, JA

    2007-01-01

    The aim of the present study was to evaluate the accuracy of birth notification data collected during Birth to Ten, a longitudinal birth cohort study based in the Soweto-Johannesburg Metropole. Photocopies of birth notification forms were obtained from three local health authorities (Soweto, Diepmeadow and Johannesburg) for 5 448 of the 5 460 singleton births that occurred during seven weeks between April and June 1990, to women resident in Soweto-Johannesburg. By comparing the data recorded on the three different types of notification forms used by delivery centres within the Metropole, it was possible to assess the consistency of data collected during birth notification. For 539 of the 2 120 births that occurred at Baragwanath Hospital in Soweto, it was possible to locate the original records of maternal age, gravidity, infant sex, date of birth, birth weight and gestational age at birth, contained in obstetric and neonatal hospital files. By comparing these records with information contained in the birth notification forms it was possible to assess the accuracy of birth notification data submitted for deliveries at Baragwanath Hospital. Each of the different notification forms contained a different selection of variables and failed to specify the precision with which continuous variables should be recorded. For 12 selected variables, the proportion of missing records ranged from 0.0% to 40.9%, and was highest for those variables (such as APGAR scores and parity) that were not required on all four forms. The percentage agreement between information recorded on these forms and the original hospital records was highest for the categorical variable infant sex (99.1%), while the accuracy of notification data for continuous variables ranged from 95.2% (maternal age) to 29.7% (gestational age at birth). The upper 95% confidence intervals for the mean absolute errors in gestational age at birth and birth weight were two to three times the units of measurement, at 2

  3. Spacecraft attitude determination accuracy from mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, D.; Hashmall, J.; Baker, D.

    1994-01-01

    This document presents a compilation of the attitude accuracy attained by a number of satellites that have been supported by the Flight Dynamics Facility (FDF) at Goddard Space Flight Center (GSFC). It starts with a general description of the factors that influence spacecraft attitude accuracy. After brief descriptions of the missions supported, it presents the attitude accuracy results for currently active and older missions, including both three-axis stabilized and spin-stabilized spacecraft. The attitude accuracy results are grouped by the sensor pair used to determine the attitudes. A supplementary section is also included, containing the results of theoretical computations of the effects of variation of sensor accuracy on overall attitude accuracy.

  4. Reporting the accuracy of biochemical measurements for epidemiologic and nutrition studies.

    PubMed

    McShane, L M; Clark, L C; Combs, G F; Turnbull, B W

    1991-06-01

    Procedures for reporting and monitoring the accuracy of biochemical measurements are presented. They are proposed as standard reporting procedures for laboratory assays for epidemiologic and clinical-nutrition studies. The recommended procedures require identification and estimation of all major sources of variability and explanations of laboratory quality control procedures employed. Variance-components techniques are used to model the total variability and calculate a maximum percent error that provides an easily understandable measure of laboratory precision accounting for all sources of variability. This avoids ambiguities encountered when reporting an SD that may taken into account only a few of the potential sources of variability. Other proposed uses of the total-variability model include estimating precision of laboratory methods for various replication schemes and developing effective quality control-checking schemes. These procedures are demonstrated with an example of the analysis of alpha-tocopherol in human plasma by using high-performance liquid chromatography.

  5. Influence of learner knowledge and case complexity on handover accuracy and cognitive load: results from a simulation study.

    PubMed

    Young, John Q; van Dijk, Savannah M; O'Sullivan, Patricia S; Custers, Eugene J; Irby, David M; Ten Cate, Olle

    2016-09-01

    The handover represents a high-risk event in which errors are common and lead to patient harm. A better understanding of the cognitive mechanisms of handover errors is essential to improving handover education and practice. This paper reports on an experiment conducted to study the effects of learner knowledge, case complexity (i.e. cases with or without a clear diagnosis) and their interaction on handover accuracy and cognitive load. Participants were 52 Dutch medical students in Years 2 and 6. The experiment employed a repeated-measures design with two explanatory variables: case complexity (simple or complex) as the within-subject variable, and learner knowledge (as indicated by illness script maturity) as the between-subject covariate. The dependent variables were handover accuracy and cognitive load. Each participant performed a total of four simulated handovers involving two simple cases and two complex cases. Higher illness script maturity predicted increased handover accuracy (p < 0.001) and lower cognitive load (p = 0.007). Case complexity did not independently affect either outcome. For handover accuracy, there was no interaction between case complexity and illness script maturity. For cognitive load, there was an interaction effect between illness script maturity and case complexity, indicating that more mature illness scripts reduced cognitive load less in complex cases than in simple cases. Students with more mature illness scripts performed more accurate handovers and experienced lower cognitive load. For cognitive load, these effects were more pronounced in simple than complex cases. If replicated, these findings suggest that handover curricula and protocols should provide support that varies according to the knowledge of the trainee. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  6. Qualitative and quantitative three-dimensional accuracy of a single tooth captured by elastomeric impression materials: an in vitro study.

    PubMed

    Schaefer, Oliver; Schmidt, Monika; Goebel, Roland; Kuepper, Harald

    2012-09-01

    The accuracy of impressions has been described in 1 or 2 dimensions, whereas it is most desirable to evaluate the accuracy of impressions spatially, in 3 dimensions. The purpose of this study was to demonstrate the accuracy and reproducibility of a 3-dimensional (3-D) approach to assessing impression preciseness and to quantitatively comparing the occlusal correctness of gypsum dies made with different impression materials. By using an aluminum replica of a maxillary molar, single-step dual viscosity impressions were made with 1 polyether/vinyl polysiloxane hybrid material (Identium), 1 vinyl polysiloxane (Panasil), and 1 polyether (Impregum) (n=5). Corresponding dies were made of Type IV gypsum and were optically digitized and aligned to the virtual reference of the aluminum tooth. Accuracy was analyzed by computing mean quadratic deviations between the virtual reference and the gypsum dies, while deviations of the dies among one another determined the reproducibility of the method. The virtual reference was adapted to create 15 occlusal contact points. The percentage of contact points deviating within a ±10 µm tolerance limit (PDP(10) = Percentage of Deviating Points within ±10 µm Tolerance) was set as the index for assessing occlusal accuracy. Visual results for the difference from the reference tooth were displayed with colors, whereas mean deviation values as well as mean PDP(10) differences were analyzed with a 1-way ANOVA and Scheffé post hoc comparisons (α=.05). Objective characterization of accuracy showed smooth axial surfaces to be undersized, whereas occlusal surfaces were accurate or enlarged when compared to the original tooth. The accuracy of the gypsum replicas ranged between 3 and 6 µm, while reproducibility results varied from 2 to 4 µm. Mean (SD) PDP(10)-values were: Panasil 91% (±11), Identium 77% (±4) and Impregum 29% (±3). One-way ANOVA detected significant differences among the subjected impression materials (P<.001). The accuracy

  7. Accuracy of a computer-aided surgical simulation protocol for orthognathic surgery: a prospective multicenter study.

    PubMed

    Hsu, Sam Sheng-Pin; Gateno, Jaime; Bell, R Bryan; Hirsch, David L; Markiewicz, Michael R; Teichgraeber, John F; Zhou, Xiaobo; Xia, James J

    2013-01-01

    The purpose of this prospective multicenter study was to assess the accuracy of a computer-aided surgical simulation (CASS) protocol for orthognathic surgery. The accuracy of the CASS protocol was assessed by comparing planned outcomes with postoperative outcomes of 65 consecutive patients enrolled from 3 centers. Computer-generated surgical splints were used for all patients. For the genioplasty, 1 center used computer-generated chin templates to reposition the chin segment only for patients with asymmetry. Standard intraoperative measurements were used without the chin templates for the remaining patients. The primary outcome measurements were the linear and angular differences for the maxilla, mandible, and chin when the planned and postoperative models were registered at the cranium. The secondary outcome measurements were the maxillary dental midline difference between the planned and postoperative positions and the linear and angular differences of the chin segment between the groups with and without the use of the template. The latter were measured when the planned and postoperative models were registered at the mandibular body. Statistical analyses were performed, and the accuracy was reported using root mean square deviation (RMSD) and the Bland-Altman method for assessing measurement agreement. In the primary outcome measurements, there was no statistically significant difference among the 3 centers for the maxilla and mandible. The largest RMSDs were 1.0 mm and 1.5° for the maxilla and 1.1 mm and 1.8° for the mandible. For the chin, there was a statistically significant difference between the groups with and without the use of the chin template. The chin template group showed excellent accuracy, with the largest positional RMSD of 1.0 mm and the largest orientation RMSD of 2.2°. However, larger variances were observed in the group not using the chin template. This was significant in the anteroposterior and superoinferior directions and the in pitch

  8. Geoid undulation accuracy

    NASA Technical Reports Server (NTRS)

    Rapp, Richard H.

    1993-01-01

    The determination of the geoid and equipotential surface of the Earth's gravity field, has long been of interest to geodesists and oceanographers. The geoid provides a surface to which the actual ocean surface can be compared with the differences implying information on the circulation patterns of the oceans. For use in oceanographic applications the geoid is ideally needed to a high accuracy and to a high resolution. There are applications that require geoid undulation information to an accuracy of +/- 10 cm with a resolution of 50 km. We are far from this goal today but substantial improvement in geoid determination has been made. In 1979 the cumulative geoid undulation error to spherical harmonic degree 20 was +/- 1.4 m for the GEM10 potential coefficient model. Today the corresponding value has been reduced to +/- 25 cm for GEM-T3 or +/- 11 cm for the OSU91A model. Similar improvements are noted by harmonic degree (wave-length) and in resolution. Potential coefficient models now exist to degree 360 based on a combination of data types. This paper discusses the accuracy changes that have taken place in the past 12 years in the determination of geoid undulations.

  9. Evaluation of Factors Influencing Accuracy of Principal Procedure Coding Based on ICD-9-CM: An Iranian Study

    PubMed Central

    Farzandipour, Mehrdad; Sheikhtaheri, Abbas

    2009-01-01

    To evaluate the accuracy of procedural coding and the factors that influence it, 246 records were randomly selected from four teaching hospitals in Kashan, Iran. “Recodes” were assigned blindly and then compared to the original codes. Furthermore, the coders' professional behaviors were carefully observed during the coding process. Coding errors were classified as major or minor. The relations between coding accuracy and possible effective factors were analyzed by χ2 or Fisher exact tests as well as the odds ratio (OR) and the 95 percent confidence interval for the OR. The results showed that using a tabular index for rechecking codes reduces errors (83 percent vs. 72 percent accuracy). Further, more thorough documentation by the clinician positively affected coding accuracy, though this relation was not significant. Readability of records decreased errors overall (p = .003), including major ones (p = .012). Moreover, records with no abbreviations had fewer major errors (p = .021). In conclusion, not using abbreviations, ensuring more readable documentation, and paying more attention to available information increased coding accuracy and the quality of procedure databases. PMID:19471647

  10. Effects of cognitive training on change in accuracy in inductive reasoning ability.

    PubMed

    Boron, Julie Blaskewicz; Turiano, Nicholas A; Willis, Sherry L; Schaie, K Warner

    2007-05-01

    We investigated cognitive training effects on accuracy and number of items attempted in inductive reasoning performance in a sample of 335 older participants (M = 72.78 years) from the Seattle Longitudinal Study. We assessed the impact of individual characteristics, including chronic disease. The reasoning training group showed significantly greater gain in accuracy and number of attempted items than did the comparison group; gain was primarily due to enhanced accuracy. Reasoning training effects involved a complex interaction of gender, prior cognitive status, and chronic disease. Women with prior decline on reasoning but no heart disease showed the greatest accuracy increase. In addition, stable reasoning-trained women with heart disease demonstrated significant accuracy gain. Comorbidity was associated with less change in accuracy. The results support the effectiveness of cognitive training on improving the accuracy of reasoning performance.

  11. Anatomy-aware measurement of segmentation accuracy

    NASA Astrophysics Data System (ADS)

    Tizhoosh, H. R.; Othman, A. A.

    2016-03-01

    Quantifying the accuracy of segmentation and manual delineation of organs, tissue types and tumors in medical images is a necessary measurement that suffers from multiple problems. One major shortcoming of all accuracy measures is that they neglect the anatomical significance or relevance of different zones within a given segment. Hence, existing accuracy metrics measure the overlap of a given segment with a ground-truth without any anatomical discrimination inside the segment. For instance, if we understand the rectal wall or urethral sphincter as anatomical zones, then current accuracy measures ignore their significance when they are applied to assess the quality of the prostate gland segments. In this paper, we propose an anatomy-aware measurement scheme for segmentation accuracy of medical images. The idea is to create a "master gold" based on a consensus shape containing not just the outline of the segment but also the outlines of the internal zones if existent or relevant. To apply this new approach to accuracy measurement, we introduce the anatomy-aware extensions of both Dice coefficient and Jaccard index and investigate their effect using 500 synthetic prostate ultrasound images with 20 different segments for each image. We show that through anatomy-sensitive calculation of segmentation accuracy, namely by considering relevant anatomical zones, not only the measurement of individual users can change but also the ranking of users' segmentation skills may require reordering.

  12. Assessment of the accuracy and stability of frameless gamma knife radiosurgery.

    PubMed

    Chung, Hyun-Tai; Park, Woo-Yoon; Kim, Tae Hoon; Kim, Yong Kyun; Chun, Kook Jin

    2018-06-03

    The aim of this study was to assess the accuracy and stability of frameless gamma knife radiosurgery (GKRS). The accuracies of the radiation isocenter and patient couch movement were evaluated by film dosimetry with a half-year cycle. Radiation isocenter assessment with a diode detector and cone-beam computed tomography (CBCT) image accuracy tests were performed daily with a vendor-provided tool for one and a half years after installation. CBCT image quality was examined twice a month with a phantom. The accuracy of image coregistration using CBCT images was studied using magnetic resonance (MR) and computed tomography (CT) images of another phantom. The overall positional accuracy was measured in whole procedure tests using film dosimetry with an anthropomorphic phantom. The positional errors of the radiation isocenter at the center and at an extreme position were both less than 0.1 mm. The three-dimensional deviation of the CBCT coordinate system was stable for one and a half years (mean 0.04 ± 0.02 mm). Image coregistration revealed a difference of 0.2 ± 0.1 mm between CT and CBCT images and a deviation of 0.4 ± 0.2 mm between MR and CBCT images. The whole procedure test of the positional accuracy of the mask-based irradiation revealed an accuracy of 0.5 ± 0.6 mm. The radiation isocenter accuracy, patient couch movement accuracy, and Gamma Knife Icon CBCT accuracy were all approximately 0.1 mm and were stable for one and a half years. The coordinate system assigned to MR images through coregistration was more accurate than the system defined by fiducial markers. Possible patient motion during irradiation should be considered when evaluating the overall accuracy of frameless GKRS. © 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  13. Surgical Navigation Technology Based on Augmented Reality and Integrated 3D Intraoperative Imaging: A Spine Cadaveric Feasibility and Accuracy Study.

    PubMed

    Elmi-Terander, Adrian; Skulason, Halldor; Söderman, Michael; Racadio, John; Homan, Robert; Babic, Drazenko; van der Vaart, Nijs; Nachabe, Rami

    2016-11-01

    A cadaveric laboratory study. The aim of this study was to assess the feasibility and accuracy of thoracic pedicle screw placement using augmented reality surgical navigation (ARSN). Recent advances in spinal navigation have shown improved accuracy in lumbosacral pedicle screw placement but limited benefits in the thoracic spine. 3D intraoperative imaging and instrument navigation may allow improved accuracy in pedicle screw placement, without the use of x-ray fluoroscopy, and thus opens the route to image-guided minimally invasive therapy in the thoracic spine. ARSN encompasses a surgical table, a motorized flat detector C-arm with intraoperative 2D/3D capabilities, integrated optical cameras for augmented reality navigation, and noninvasive patient motion tracking. Two neurosurgeons placed 94 pedicle screws in the thoracic spine of four cadavers using ARSN on one side of the spine (47 screws) and free-hand technique on the contralateral side. X-ray fluoroscopy was not used for either technique. Four independent reviewers assessed the postoperative scans, using the Gertzbein grading. Morphometric measurements of the pedicles axial and sagittal widths and angles, as well as the vertebrae axial and sagittal rotations were performed to identify risk factors for breaches. ARSN was feasible and superior to free-hand technique with respect to overall accuracy (85% vs. 64%, P < 0.05), specifically significant increases of perfectly placed screws (51% vs. 30%, P < 0.05) and reductions in breaches beyond 4 mm (2% vs. 25%, P < 0.05). All morphometric dimensions, except for vertebral body axial rotation, were risk factors for larger breaches when performed with the free-hand method. ARSN without fluoroscopy was feasible and demonstrated higher accuracy than free-hand technique for thoracic pedicle screw placement. N/A.

  14. PubChem3D: conformer ensemble accuracy

    PubMed Central

    2013-01-01

    Background PubChem is a free and publicly available resource containing substance descriptions and their associated biological activity information. PubChem3D is an extension to PubChem containing computationally-derived three-dimensional (3-D) structures of small molecules. All the tools and services that are a part of PubChem3D rely upon the quality of the 3-D conformer models. Construction of the conformer models currently available in PubChem3D involves a clustering stage to sample the conformational space spanned by the molecule. While this stage allows one to downsize the conformer models to more manageable size, it may result in a loss of the ability to reproduce experimentally determined “bioactive” conformations, for example, found for PDB ligands. This study examines the extent of this accuracy loss and considers its effect on the 3-D similarity analysis of molecules. Results The conformer models consisting of up to 100,000 conformers per compound were generated for 47,123 small molecules whose structures were experimentally determined, and the conformers in each conformer model were clustered to reduce the size of the conformer model to a maximum of 500 conformers per molecule. The accuracy of the conformer models before and after clustering was evaluated using five different measures: root-mean-square distance (RMSD), shape-optimized shape-Tanimoto (STST-opt) and combo-Tanimoto (ComboTST-opt), and color-optimized color-Tanimoto (CTCT-opt) and combo-Tanimoto (ComboTCT-opt). On average, the effect of clustering decreased the conformer model accuracy, increasing the conformer ensemble’s RMSD to the bioactive conformer (by 0.18 ± 0.12 Å), and decreasing the STST-opt, ComboTST-opt, CTCT-opt, and ComboTCT-opt scores (by 0.04 ± 0.03, 0.16 ± 0.09, 0.09 ± 0.05, and 0.15 ± 0.09, respectively). Conclusion This study shows the RMSD accuracy performance of the PubChem3D conformer models is operating as designed. In addition, the effect of PubChem3D

  15. Modeling Individual Differences in Response Time and Accuracy in Numeracy

    PubMed Central

    Ratcliff, Roger; Thompson, Clarissa A.; McKoon, Gail

    2015-01-01

    In the study of numeracy, some hypotheses have been based on response time (RT) as a dependent variable and some on accuracy, and considerable controversy has arisen about the presence or absence of correlations between RT and accuracy, between RT or accuracy and individual differences like IQ and math ability, and between various numeracy tasks. In this article, we show that an integration of the two dependent variables is required, which we accomplish with a theory-based model of decision making. We report data from four tasks: numerosity discrimination, number discrimination, memory for two-digit numbers, and memory for three-digit numbers. Accuracy correlated across tasks, as did RTs. However, the negative correlations that might be expected between RT and accuracy were not obtained; if a subject was accurate, it did not mean that they were fast (and vice versa). When the diffusion decision-making model was applied to the data (Ratcliff, 1978), we found significant correlations across the tasks between the quality of the numeracy information (drift rate) driving the decision process and between the speed/ accuracy criterion settings, suggesting that similar numeracy skills and similar speed-accuracy settings are involved in the four tasks. In the model, accuracy is related to drift rate and RT is related to speed-accuracy criteria, but drift rate and criteria are not related to each other across subjects. This provides a theoretical basis for understanding why negative correlations were not obtained between accuracy and RT. We also manipulated criteria by instructing subjects to maximize either speed or accuracy, but still found correlations between the criteria settings between and within tasks, suggesting that the settings may represent an individual trait that can be modulated but not equated across subjects. Our results demonstrate that a decision-making model may provide a way to reconcile inconsistent and sometimes contradictory results in numeracy

  16. Accuracy of Digital vs. Conventional Implant Impressions

    PubMed Central

    Lee, Sang J.; Betensky, Rebecca A.; Gianneschi, Grace E.; Gallucci, German O.

    2015-01-01

    The accuracy of digital impressions greatly influences the clinical viability in implant restorations. The aim of this study is to compare the accuracy of gypsum models acquired from the conventional implant impression to digitally milled models created from direct digitalization by three-dimensional analysis. Thirty gypsum and 30 digitally milled models impressed directly from a reference model were prepared. The models were scanned by a laboratory scanner and 30 STL datasets from each group were imported to an inspection software. The datasets were aligned to the reference dataset by a repeated best fit algorithm and 10 specified contact locations of interest were measured in mean volumetric deviations. The areas were pooled by cusps, fossae, interproximal contacts, horizontal and vertical axes of implant position and angulation. The pooled areas were statistically analysed by comparing each group to the reference model to investigate the mean volumetric deviations accounting for accuracy and standard deviations for precision. Milled models from digital impressions had comparable accuracy to gypsum models from conventional impressions. However, differences in fossae and vertical displacement of the implant position from the gypsum and digitally milled models compared to the reference model, exhibited statistical significance (p<0.001, p=0.020 respectively). PMID:24720423

  17. Bullet trajectory reconstruction - Methods, accuracy and precision.

    PubMed

    Mattijssen, Erwin J A T; Kerkhoff, Wim

    2016-05-01

    Based on the spatial relation between a primary and secondary bullet defect or on the shape and dimensions of the primary bullet defect, a bullet's trajectory prior to impact can be estimated for a shooting scene reconstruction. The accuracy and precision of the estimated trajectories will vary depending on variables such as, the applied method of reconstruction, the (true) angle of incidence, the properties of the target material and the properties of the bullet upon impact. This study focused on the accuracy and precision of estimated bullet trajectories when different variants of the probing method, ellipse method, and lead-in method are applied on bullet defects resulting from shots at various angles of incidence on drywall, MDF and sheet metal. The results show that in most situations the best performance (accuracy and precision) is seen when the probing method is applied. Only for the lowest angles of incidence the performance was better when either the ellipse or lead-in method was applied. The data provided in this paper can be used to select the appropriate method(s) for reconstruction and to correct for systematic errors (accuracy) and to provide a value of the precision, by means of a confidence interval of the specific measurement. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  18. Children's use of decomposition strategies mediates the visuospatial memory and arithmetic accuracy relation.

    PubMed

    Foley, Alana E; Vasilyeva, Marina; Laski, Elida V

    2017-06-01

    This study examined the mediating role of children's use of decomposition strategies in the relation between visuospatial memory (VSM) and arithmetic accuracy. Children (N = 78; Age M = 9.36) completed assessments of VSM, arithmetic strategies, and arithmetic accuracy. Consistent with previous findings, VSM predicted arithmetic accuracy in children. Extending previous findings, the current study showed that the relation between VSM and arithmetic performance was mediated by the frequency of children's use of decomposition strategies. Identifying the role of arithmetic strategies in this relation has implications for increasing the math performance of children with lower VSM. Statement of contribution What is already known on this subject? The link between children's visuospatial working memory and arithmetic accuracy is well documented. Frequency of decomposition strategy use is positively related to children's arithmetic accuracy. Children's spatial skill positively predicts the frequency with which they use decomposition. What does this study add? Short-term visuospatial memory (VSM) positively relates to the frequency of children's decomposition use. Decomposition use mediates the relation between short-term VSM and arithmetic accuracy. Children with limited short-term VSM may struggle to use decomposition, decreasing accuracy. © 2016 The British Psychological Society.

  19. Accuracy of a real-time continuous glucose monitoring system in children with septic shock: A pilot study.

    PubMed

    Prabhudesai, Sumant; Kanjani, Amruta; Bhagat, Isha; Ravikumar, Karnam G; Ramachandran, Bala

    2015-11-01

    The aim of this prospective, observational study was to determine the accuracy of a real-time continuous glucose monitoring system (CGMS) in children with septic shock. Children aged 30 days to 18 years admitted to the Pediatric Intensive Care Unit with septic shock were included. A real-time CGMS sensor was used to obtain interstitial glucose readings. CGMS readings were compared statistically with simultaneous laboratory blood glucose (BG). Nineteen children were included, and 235 pairs of BG-CGMS readings were obtained. BG and CGMS had a correlation coefficient of 0.61 (P < 0.001) and a median relative absolute difference of 17.29%. On Clarke's error grid analysis, 222 (94.5%) readings were in the clinically acceptable zones (A and B). When BG was < 70, 70-180, and > 180 mg/dL, 44%, 100%, and 76.9% readings were in zones A and B, respectively (P < 0.001). The accuracy of CGMS was not affected by the presence of edema, acidosis, vasopressors, steroids, or renal replacement therapy. On receiver operating characteristics curve analysis, a CGMS reading <97 mg/dL predicted hypoglycemia (sensitivity 85.2%, specificity 75%, area under the curve [AUC] =0.85). A reading > 141 mg/dL predicted hyperglycemia (sensitivity 84.6%, specificity 89.6%, AUC = 0.87). CGMS provides a fairly, accurate estimate of BG in children with septic shock. It is unaffected by a variety of clinical variables. The accuracy over extremes of blood sugar may be a concern. We recommend larger studies to evaluate its use for the early detection of hypoglycemia and hyperglycemia.

  20. Students' Accuracy of Measurement Estimation: Context, Units, and Logical Thinking

    ERIC Educational Resources Information Center

    Jones, M. Gail; Gardner, Grant E.; Taylor, Amy R.; Forrester, Jennifer H.; Andre, Thomas

    2012-01-01

    This study examined students' accuracy of measurement estimation for linear distances, different units of measure, task context, and the relationship between accuracy estimation and logical thinking. Middle school students completed a series of tasks that included estimating the length of various objects in different contexts and completed a test…

  1. Sex differences in accuracy and precision when judging time to arrival: data from two Internet studies.

    PubMed

    Sanders, Geoff; Sinclair, Kamila

    2011-12-01

    We report two Internet studies that investigated sex differences in the accuracy and precision of judging time to arrival. We used accuracy to mean the ability to match the actual time to arrival and precision to mean the consistency with which each participant made their judgments. Our task was presented as a computer game in which a toy UFO moved obliquely towards the participant through a virtual three-dimensional space on route to a docking station. The UFO disappeared before docking and participants pressed their space bar at the precise moment they thought the UFO would have docked. Study 1 showed it was possible to conduct quantitative studies of spatiotemporal judgments in virtual reality via the Internet and confirmed reports that men are more accurate because women underestimate, but found no difference in precision measured as intra-participant variation. Study 2 repeated Study 1 with five additional presentations of one condition to provide a better measure of precision. Again, men were more accurate than women but there were no sex differences in precision. However, within the coincidence-anticipation timing (CAT) literature, of those studies that report sex differences, a majority found that males are both more accurate and more precise than females. Noting that many CAT studies report no sex differences, we discuss appropriate interpretations of such null findings. While acknowledging that CAT performance may be influenced by experience we suggest that the sex difference may have originated among our ancestors with the evolutionary selection of men for hunting and women for gathering.

  2. The diagnostic accuracy of the GenoType® Mtbdrsl assay for the detection of resistance to second-line anti-tuberculosis drugs

    PubMed Central

    Theron, Grant; Peter, Jonny; Richardson, Marty; Barnard, Marinus; Donegan, Sarah; Warren, Rob; Steingart, Karen R; Dheda, Keertan

    2014-01-01

    standardized form and assessed study quality using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We performed meta-analyses to estimate the pooled sensitivity and specificity of MTBDRsl for FQ resistance, SLID resistance, and XDR-TB. We explored the influence of different reference standards. We performed the majority of analyses using a bivariate random-effects model against culture-based DST as the reference standard. Main results We included 21 unique studies: 14 studies reported the accuracy of MTBDRsl when done directly, five studies when done indirectly and two studies that did both. Of the 21 studies, 15 studies (71%) were cross-sectional and 11 studies (58%) were located in lowincome or middle-income countries. All studies but two were written in English. Nine (43%) of the 21 included studies had a high risk of bias for patient selection. At least half of the studies had low risk of bias for the other QUADAS-2 domains. As a test for FQ resistance measured against culture-based DST, the pooled sensitivity of MTBDRsl when performed indirectly was 83.1% (95% confidence interval (CI) 78.7% to 86.7%) and the pooled specificity was 97.7% (95% CI 94.3% to 99.1%), respectively (16 studies, 1766 participants; 610 confirmed cases of FQ-resistant TB; moderate quality evidence).When performed directly, the pooled sensitivity was 85.1% (95% CI 71.9% to 92.7%) and the pooled specificity was 98.2% (95% CI 96.8% to 99.0%), respectively (seven studies, 1033 participants; 230 confirmed cases of FQ-resistant TB; moderate quality evidence). For indirect testing for FQ resistance, four (0.2%) of 1766MTBDRsl results were indeterminate, whereas for direct testing 20 (1.9%) of 1033 wereMTBDRsl indeterminate (P < 0.001). As a test for SLID resistance measured against culture-based DST, the pooled sensitivity of MTBDRsl when performed indirectly was 76.9% (95% CI 61.1% to 87.6%) and the pooled specificity was 99.5% (95% CI 97.1% to 99.9%), respectively (14 studies, 1637

  3. A vine copula mixed effect model for trivariate meta-analysis of diagnostic test accuracy studies accounting for disease prevalence.

    PubMed

    Nikoloulopoulos, Aristidis K

    2017-10-01

    A bivariate copula mixed model has been recently proposed to synthesize diagnostic test accuracy studies and it has been shown that it is superior to the standard generalized linear mixed model in this context. Here, we call trivariate vine copulas to extend the bivariate meta-analysis of diagnostic test accuracy studies by accounting for disease prevalence. Our vine copula mixed model includes the trivariate generalized linear mixed model as a special case and can also operate on the original scale of sensitivity, specificity, and disease prevalence. Our general methodology is illustrated by re-analyzing the data of two published meta-analyses. Our study suggests that there can be an improvement on trivariate generalized linear mixed model in fit to data and makes the argument for moving to vine copula random effects models especially because of their richness, including reflection asymmetric tail dependence, and computational feasibility despite their three dimensionality.

  4. Geometrical accuracy of metallic objects produced with additive or subtractive manufacturing: A comparative in vitro study.

    PubMed

    Braian, Michael; Jönsson, David; Kevci, Mir; Wennerberg, Ann

    2018-07-01

    To evaluate the accuracy and precision of objects produced by additive manufacturing systems (AM) for use in dentistry and to compare with subtractive manufacturing systems (SM). Ten specimens of two geometrical objects were produced by five different AM machines and one SM machine. Object A mimics an inlay-shaped object, while object B imitates a four-unit bridge model. All the objects were sorted into different measurement dimensions (x, y, z), linear distances, angles and corner radius. None of the additive manufacturing or subtractive manufacturing groups presented a perfect match to the CAD file with regard to all parameters included in the present study. Considering linear measurements, the precision for subtractive manufacturing group was consistent in all axes for object A, presenting results of <0.050mm. The additive manufacturing groups had consistent precision in the x-axis and y-axis but not in the z-axis. With regard to corner radius measurements, the SM group had the best overall accuracy and precision for both objects A and B when compared to the AM groups. Within the limitations of this in vitro study, the conclusion can be made that subtractive manufacturing presented overall precision on all measurements below 0.050mm. The AM machines also presented fairly good precision, <0.150mm, on all axes except for the z-axis. Knowledge regarding accuracy and precision for different production techniques utilized in dentistry is of great clinical importance. The dental community has moved from casting to milling and additive techniques are now being implemented. Thus all these production techniques need to be tested, compared and validated. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

  5. Recommended aerobic fitness level for metabolic health in children and adolescents: a study of diagnostic accuracy.

    PubMed

    Adegboye, Amanda R A; Anderssen, Sigmund A; Froberg, Karsten; Sardinha, Luis B; Heitmann, Berit L; Steene-Johannessen, Jostein; Kolle, Elin; Andersen, Lars B

    2011-07-01

    To define the optimal cut-off for low aerobic fitness and to evaluate its accuracy to predict clustering of risk factors for cardiovascular disease in children and adolescents. Study of diagnostic accuracy using a cross-sectional database. European Youth Heart Study including Denmark, Portugal, Estonia and Norway. 4500 schoolchildren aged 9 or 15 years. Aerobic fitness was expressed as peak oxygen consumption relative to bodyweight (mlO(2)/min/kg). Risk factors included in the composite risk score (mean of z-scores) were systolic blood pressure, triglyceride, total cholesterol/HDL-cholesterol ratio, insulin resistance and sum of four skinfolds. 14.5% of the sample, with a risk score above one SD, were defined as being at risk. Receiver operating characteristic analysis was used to define the optimal cut-off for sex and age-specific distribution. In girls, the optimal cut-offs for identifying individuals at risk were: 37.4 mlO(2)/min/kg (9-year-old) and 33.0 mlO(2)/min/kg (15-year-old). In boys, the optimal cut-offs were 43.6 mlO(2)/min/kg (9-year-old) and 46.0 mlO(2)/min/kg (15-year-old). Specificity (range 79.3-86.4%) was markedly higher than sensitivity (range 29.7-55.6%) for all cut-offs. Positive predictive values ranged from 19% to 41% and negative predictive values ranged from 88% to 90%. The diagnostic accuracy for identifying children at risk, measured by the area under the curve (AUC), was significantly higher than what would be expected by chance (AUC >0.5) for all cut-offs. Aerobic fitness is easy to measure, and is an accurate tool for screening children with clustering of cardiovascular risk factors. Promoting physical activity in children with aerobic fitness level lower than the suggested cut-points might improve their health.

  6. Diagnostic accuracy of imaging devices in glaucoma: A meta-analysis.

    PubMed

    Fallon, Monica; Valero, Oliver; Pazos, Marta; Antón, Alfonso

    Imaging devices such as the Heidelberg retinal tomograph-3 (HRT3), scanning laser polarimetry (GDx), and optical coherence tomography (OCT) play an important role in glaucoma diagnosis. A systematic search for evidence-based data was performed for prospective studies evaluating the diagnostic accuracy of HRT3, GDx, and OCT. The diagnostic odds ratio (DOR) was calculated. To compare the accuracy among instruments and parameters, a meta-analysis considering the hierarchical summary receiver-operating characteristic model was performed. The risk of bias was assessed using quality assessment of diagnostic accuracy studies, version 2. Studies in the context of screening programs were used for qualitative analysis. Eighty-six articles were included. The DOR values were 29.5 for OCT, 18.6 for GDx, and 13.9 for HRT. The heterogeneity analysis demonstrated statistically a significant influence of degree of damage and ethnicity. Studies analyzing patients with earlier glaucoma showed poorer results. The risk of bias was high for patient selection. Screening studies showed lower sensitivity values and similar specificity values when compared with those included in the meta-analysis. The classification capabilities of GDx, HRT, and OCT were high and similar across the 3 instruments. The highest estimated DOR was obtained with OCT. Diagnostic accuracy could be overestimated in studies including prediagnosed groups of subjects. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. The Effect of Delayed-JOLs and Sentence Generation on Children's Monitoring Accuracy and Regulation of Idiom Study

    ERIC Educational Resources Information Center

    van Loon, Mariëtte H.; de Bruin, Anique B. H.; van Gog, Tamara; van Merriënboer, Jeroen J. G.

    2013-01-01

    When studying verbal materials, both adults and children are often poor at accurately monitoring their level of learning and regulating their subsequent restudy of materials, which leads to suboptimal test performance. The present experiment investigated how monitoring accuracy and regulation of study could be improved when learning idiomatic…

  8. The study of vehicle classification equipment with solutions to improve accuracy in Oklahoma.

    DOT National Transportation Integrated Search

    2014-12-01

    The accuracy of vehicle counting and classification data is vital for appropriate future highway and road : design, including determining pavement characteristics, eliminating traffic jams, and improving safety. : Organizations relying on vehicle cla...

  9. Error and Uncertainty in the Accuracy Assessment of Land Cover Maps

    NASA Astrophysics Data System (ADS)

    Sarmento, Pedro Alexandre Reis

    Traditionally the accuracy assessment of land cover maps is performed through the comparison of these maps with a reference database, which is intended to represent the "real" land cover, being this comparison reported with the thematic accuracy measures through confusion matrixes. Although, these reference databases are also a representation of reality, containing errors due to the human uncertainty in the assignment of the land cover class that best characterizes a certain area, causing bias in the thematic accuracy measures that are reported to the end users of these maps. The main goal of this dissertation is to develop a methodology that allows the integration of human uncertainty present in reference databases in the accuracy assessment of land cover maps, and analyse the impacts that uncertainty may have in the thematic accuracy measures reported to the end users of land cover maps. The utility of the inclusion of human uncertainty in the accuracy assessment of land cover maps is investigated. Specifically we studied the utility of fuzzy sets theory, more precisely of fuzzy arithmetic, for a better understanding of human uncertainty associated to the elaboration of reference databases, and their impacts in the thematic accuracy measures that are derived from confusion matrixes. For this purpose linguistic values transformed in fuzzy intervals that address the uncertainty in the elaboration of reference databases were used to compute fuzzy confusion matrixes. The proposed methodology is illustrated using a case study in which the accuracy assessment of a land cover map for Continental Portugal derived from Medium Resolution Imaging Spectrometer (MERIS) is made. The obtained results demonstrate that the inclusion of human uncertainty in reference databases provides much more information about the quality of land cover maps, when compared with the traditional approach of accuracy assessment of land cover maps. None

  10. Influence of non-level walking on pedometer accuracy.

    PubMed

    Leicht, Anthony S; Crowther, Robert G

    2009-05-01

    The YAMAX Digiwalker pedometer has been previously confirmed as a valid and reliable monitor during level walking, however, little is known about its accuracy during non-level walking activities or between genders. Subsequently, this study examined the influence of non-level walking and gender on pedometer accuracy. Forty-six healthy adults completed 3-min bouts of treadmill walking at their normal walking pace during 11 inclines (0-10%) while another 123 healthy adults completed walking up and down 47 stairs. During walking, participants wore a YAMAX Digiwalker SW-700 pedometer with the number of steps taken and registered by the pedometer recorded. Pedometer difference (steps registered-steps taken), net error (% of steps taken), absolute error (absolute % of steps taken) and gender were examined by repeated measures two-way ANOVA and Tukey's post hoc tests. During incline walking, pedometer accuracy indices were similar between inclines and gender except for a significantly greater step difference (-7+/-5 steps vs. 1+/-4 steps) and net error (-2.4+/-1.8% for 9% vs. 0.4+/-1.2% for 2%). Step difference and net error were significantly greater during stair descent compared to stair ascent while absolute error was significantly greater during stair ascent compared to stair descent. The current study demonstrated that the YAMAX Digiwalker SW-700 pedometer exhibited good accuracy during incline walking up to 10% while it overestimated steps taken during stair ascent/descent with greater overestimation during stair descent. Stair walking activity should be documented in field studies as the YAMAX Digiwalker SW-700 pedometer overestimates this activity type.

  11. [Navigation in implantology: Accuracy assessment regarding the literature].

    PubMed

    Barrak, Ibrahim Ádám; Varga, Endre; Piffko, József

    2016-06-01

    Our objective was to assess the literature regarding the accuracy of the different static guided systems. After applying electronic literature search we found 661 articles. After reviewing 139 articles, the authors chose 52 articles for full-text evaluation. 24 studies involved accuracy measurements. Fourteen of our selected references were clinical and ten of them were in vitro (modell or cadaver). Variance-analysis (Tukey's post-hoc test; p < 0.05) was conducted to summarize the selected publications. Regarding 2819 results the average mean error at the entry point was 0.98 mm. At the level of the apex the average deviation was 1.29 mm while the mean of the angular deviation was 3,96 degrees. Significant difference could be observed between the two methods of implant placement (partially and fully guided sequence) in terms of deviation at the entry point, apex and angular deviation. Different levels of quality and quantity of evidence were available for assessing the accuracy of the different computer-assisted implant placement. The rapidly evolving field of digital dentistry and the new developments will further improve the accuracy of guided implant placement. In the interest of being able to draw dependable conclusions and for the further evaluation of the parameters used for accuracy measurements, randomized, controlled single or multi-centered clinical trials are necessary.

  12. The validity and reliability of the four square step test in different adult populations: a systematic review.

    PubMed

    Moore, Martha; Barker, Karen

    2017-09-11

    The four square step test (FSST) was first validated in healthy older adults to provide a measure of dynamic standing balance and mobility. The FSST has since been used in a variety of patient populations. The purpose of this systematic review is to determine the validity and reliability of the FSST in these different adult patient populations. The literature search was conducted to highlight all the studies that measured validity and reliability of the FSST. Six electronic databases were searched including AMED, CINAHL, MEDLINE, PEDro, Web of Science and Google Scholar. Grey literature was also searched for any documents relevant to the review. Two independent reviewers carried out study selection and quality assessment. The methodological quality was assessed using the QUADAS-2 tool, which is a validated tool for the quality assessment of diagnostic accuracy studies, and the COSMIN four-point checklist, which contains standards for evaluating reliability studies on the measurement properties of health instruments. Fifteen studies were reviewed studying community-dwelling older adults, Parkinson's disease, Huntington's disease, multiple sclerosis, vestibular disorders, post stroke, post unilateral transtibial amputation, knee pain and hip osteoarthritis. Three of the studies were of moderate methodological quality scoring low in risk of bias and applicability for all domains in the QUADAS-2 tool. Three studies scored "fair" on the COSMIN four-point checklist for the reliability components. The concurrent validity of the FSST was measured in nine of the studies with moderate to strong correlations being found. Excellent Intraclass Correlation Coefficients were found between physiotherapists carrying out the tests (ICC = .99) with good to excellent test-retest reliability shown in nine of the studies (ICC = .73-.98). The FSST may be an effective and valid tool for measuring dynamic balance and a participants' falls risk. It has been shown to have strong

  13. MAPPING SPATIAL THEMATIC ACCURACY WITH FUZZY SETS

    EPA Science Inventory

    Thematic map accuracy is not spatially homogenous but variable across a landscape. Properly analyzing and representing spatial pattern and degree of thematic map accuracy would provide valuable information for using thematic maps. However, current thematic map accuracy measures (...

  14. Apparent diffusion coefficient measurements in the differentiation between benign and malignant lesions: a systematic review.

    PubMed

    Vermoolen, M A; Kwee, T C; Nievelstein, R A J

    2012-08-01

    To systematically review the value of apparent diffusion coefficient (ADC) measurement in the differentiation between benign and malignant lesions. A systematic search of the Medline/Pubmed and Embase databases revealed 109 relevant studies. Quality of these articles was assessed using the Quality Assessment of the Studies of Diagnostic Accuracy Included in Systematic Reviews (QUADAS) criteria. Reported ADC values of benign and malignant lesions were compared per organ. The mean quality score of the reviewed articles was 50%. Comparison of ADC values showed marked variation among studies and between benign and malignant lesions in various organs. In several organs, such as breast, liver, and uterus, ADC values discriminated well between benign and malignant lesions. In other organs, such as the salivary glands, thyroid, and pancreas, ADCs were not significantly different between benign and malignant lesions. The potential utility of ADC measurement for the characterisation of tumours differs per organ. Future well-designed studies are required before ADC measurements can be recommended for the differentiation of benign and malignant lesions. These future studies should use standardised acquisition protocols and provide complete reporting of study methods, to facilitate comparison of results and clinical implementation of ADC measurement for tumour characterisation.

  15. On the neural implementation of the speed-accuracy trade-off

    PubMed Central

    Standage, Dominic; Blohm, Gunnar; Dorris, Michael C.

    2014-01-01

    Decisions are faster and less accurate when conditions favor speed, and are slower and more accurate when they favor accuracy. This phenomenon is referred to as the speed-accuracy trade-off (SAT). Behavioral studies of the SAT have a long history, and the data from these studies are well characterized within the framework of bounded integration. According to this framework, decision makers accumulate noisy evidence until the running total for one of the alternatives reaches a bound. Lower and higher bounds favor speed and accuracy respectively, each at the expense of the other. Studies addressing the neural implementation of these computations are a recent development in neuroscience. In this review, we describe the experimental and theoretical evidence provided by these studies. We structure the review according to the framework of bounded integration, describing evidence for (1) the modulation of the encoding of evidence under conditions favoring speed or accuracy, (2) the modulation of the integration of encoded evidence, and (3) the modulation of the amount of integrated evidence sufficient to make a choice. We discuss commonalities and differences between the proposed neural mechanisms, some of their assumptions and simplifications, and open questions for future work. We close by offering a unifying hypothesis on the present state of play in this nascent research field. PMID:25165430

  16. On the neural implementation of the speed-accuracy trade-off.

    PubMed

    Standage, Dominic; Blohm, Gunnar; Dorris, Michael C

    2014-01-01

    Decisions are faster and less accurate when conditions favor speed, and are slower and more accurate when they favor accuracy. This phenomenon is referred to as the speed-accuracy trade-off (SAT). Behavioral studies of the SAT have a long history, and the data from these studies are well characterized within the framework of bounded integration. According to this framework, decision makers accumulate noisy evidence until the running total for one of the alternatives reaches a bound. Lower and higher bounds favor speed and accuracy respectively, each at the expense of the other. Studies addressing the neural implementation of these computations are a recent development in neuroscience. In this review, we describe the experimental and theoretical evidence provided by these studies. We structure the review according to the framework of bounded integration, describing evidence for (1) the modulation of the encoding of evidence under conditions favoring speed or accuracy, (2) the modulation of the integration of encoded evidence, and (3) the modulation of the amount of integrated evidence sufficient to make a choice. We discuss commonalities and differences between the proposed neural mechanisms, some of their assumptions and simplifications, and open questions for future work. We close by offering a unifying hypothesis on the present state of play in this nascent research field.

  17. Ultrasonography for endoleak detection after endoluminal abdominal aortic aneurysm repair.

    PubMed

    Abraha, Iosief; Luchetta, Maria Laura; De Florio, Rita; Cozzolino, Francesco; Casazza, Giovanni; Duca, Piergiorgio; Parente, Basso; Orso, Massimiliano; Germani, Antonella; Eusebi, Paolo; Montedori, Alessandro

    2017-06-09

    People with abdominal aortic aneurysm who receive endovascular aneurysm repair (EVAR) need lifetime surveillance to detect potential endoleaks. Endoleak is defined as persistent blood flow within the aneurysm sac following EVAR. Computed tomography (CT) angiography is considered the reference standard for endoleak surveillance. Colour duplex ultrasound (CDUS) and contrast-enhanced CDUS (CE-CDUS) are less invasive but considered less accurate than CT. To determine the diagnostic accuracy of colour duplex ultrasound (CDUS) and contrast-enhanced-colour duplex ultrasound (CE-CDUS) in terms of sensitivity and specificity for endoleak detection after endoluminal abdominal aortic aneurysm repair (EVAR). We searched MEDLINE, Embase, LILACS, ISI Conference Proceedings, Zetoc, and trial registries in June 2016 without language restrictions and without use of filters to maximize sensitivity. Any cross-sectional diagnostic study evaluating participants who received EVAR by both ultrasound (with or without contrast) and CT scan assessed at regular intervals. Two pairs of review authors independently extracted data and assessed quality of included studies using the QUADAS 1 tool. A third review author resolved discrepancies. The unit of analysis was number of participants for the primary analysis and number of scans performed for the secondary analysis. We carried out a meta-analysis to estimate sensitivity and specificity of CDUS or CE-CDUS using a bivariate model. We analysed each index test separately. As potential sources of heterogeneity, we explored year of publication, characteristics of included participants (age and gender), direction of the study (retrospective, prospective), country of origin, number of CDUS operators, and ultrasound manufacturer. We identified 42 primary studies with 4220 participants. Twenty studies provided accuracy data based on the number of individual participants (seven of which provided data with and without the use of contrast). Sixteen of

  18. Accuracy of frozen section in the diagnosis of ovarian tumours.

    PubMed

    Toneva, F; Wright, H; Razvi, K

    2012-07-01

    The purpose of our retrospective study was to assess the accuracy of intraoperative frozen section diagnosis compared to final paraffin diagnosis in ovarian tumours at a gynaecological oncology centre in the UK. We analysed 66 cases and observed that frozen section consultation agreed with final paraffin diagnosis in 59 cases, which provided an accuracy of 89.4%. The overall sensitivity and specificity for all tumours were 85.4% and 100%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) were 100% and 89.4%, respectively. Of the seven cases with discordant results, the majority were large, mucinous tumours, which is in line with previous studies. Our study demonstrated that despite its limitations, intraoperative frozen section has a high accuracy and sensitivity for assessing ovarian tumours; however, care needs to be taken with large, mucinous tumours.

  19. Accuracy of endoscopic ultrasonography for diagnosing ulcerative early gastric cancers

    PubMed Central

    Park, Jin-Seok; Kim, Hyungkil; Bang, Byongwook; Kwon, Kyesook; Shin, Youngwoon

    2016-01-01

    Abstract Although endoscopic ultrasonography (EUS) is the first-choice imaging modality for predicting the invasion depth of early gastric cancer (EGC), the prediction accuracy of EUS is significantly decreased when EGC is combined with ulceration. The aim of present study was to compare the accuracy of EUS and conventional endoscopy (CE) for determining the depth of EGC. In addition, the various clinic-pathologic factors affecting the diagnostic accuracy of EUS, with a particular focus on endoscopic ulcer shapes, were evaluated. We retrospectively reviewed data from 236 consecutive patients with ulcerative EGC. All patients underwent EUS for estimating tumor invasion depth, followed by either curative surgery or endoscopic treatment. The diagnostic accuracy of EUS and CE was evaluated by comparing the final histologic result of resected specimen. The correlation between accuracy of EUS and characteristics of EGC (tumor size, histology, location in stomach, tumor invasion depth, and endoscopic ulcer shapes) was analyzed. Endoscopic ulcer shapes were classified into 3 groups: definite ulcer, superficial ulcer, and ill-defined ulcer. The overall accuracy of EUS and CE for predicting the invasion depth in ulcerative EGC was 68.6% and 55.5%, respectively. Of the 236 patients, 36 patients were classified as definite ulcers, 98 were superficial ulcers, and 102 were ill-defined ulcers, In univariate analysis, EUS accuracy was associated with invasion depth (P = 0.023), tumor size (P = 0.034), and endoscopic ulcer shapes (P = 0.001). In multivariate analysis, there is a significant association between superficial ulcer in CE and EUS accuracy (odds ratio: 2.977; 95% confidence interval: 1.255–7.064; P = 0.013). The accuracy of EUS for determining tumor invasion depth in ulcerative EGC was superior to that of CE. In addition, ulcer shape was an important factor that affected EUS accuracy. PMID:27472672

  20. Reliability and accuracy of four dental shade-matching devices.

    PubMed

    Kim-Pusateri, Seungyee; Brewer, Jane D; Davis, Elaine L; Wee, Alvin G

    2009-03-01

    There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (P<.001) for all comparisons except for SpectroShade versus ShadeVision (P=.033). Most devices had similar high reliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

  1. Accuracy of nursing diagnoses for identifying domestic violence against children.

    PubMed

    Apostólico, Maíra Rosa; Egry, Emiko Yoshikawa; Fornari, Lucimara Fabiana; Gessner, Rafaela

    2017-01-01

    Objective Identify nursing diagnoses involving a hypothetical situation of domestic violence against a child and the respective degrees of accuracy. Method An exploratory, evaluative, case study was conducted using a quantitative and qualitative approach, with data collected using an online instrument from 26 nurses working in the Municipal Health Network, between June and August 2010, in Curitiba, and also during the first half of 2014 in São Paulo. Both of these cities are in Brazil. Nursing diagnoses and interventions from the International Classification of Nursing Practices in Collective Health were provided, and accuracy was verified using the Nursing Diagnosis Accuracy Scale. Results Thirty-nine nursing diagnoses were identified, 27 of which were common to both cities. Of these, 15 were scored at the null level of accuracy, 11 at high accuracy and 1 at medium accuracy. Conclusion The difficulty the nurses had in defining diagnoses may be associated with the fact that nursing care generally focuses on clinical problems, and signs expressing situations of domestic violence against children go unnoticed. The results demonstrated the difficulty of participants in selecting the appropriate nursing diagnosis for the case in question.

  2. Photon caliper to achieve submillimeter positioning accuracy

    NASA Astrophysics Data System (ADS)

    Gallagher, Kyle J.; Wong, Jennifer; Zhang, Junan

    2017-09-01

    The purpose of this study was to demonstrate the feasibility of using a commercial two-dimensional (2D) detector array with an inherent detector spacing of 5 mm to achieve submillimeter accuracy in localizing the radiation isocenter. This was accomplished by delivering the Vernier ‘dose’ caliper to a 2D detector array where the nominal scale was the 2D detector array and the non-nominal Vernier scale was the radiation dose strips produced by the high-definition (HD) multileaf collimators (MLCs) of the linear accelerator. Because the HD MLC sequence was similar to the picket fence test, we called this procedure the Vernier picket fence (VPF) test. We confirmed the accuracy of the VPF test by offsetting the HD MLC bank by known increments and comparing the known offset with the VPF test result. The VPF test was able to determine the known offset within 0.02 mm. We also cross-validated the accuracy of the VPF test in an evaluation of couch hysteresis. This was done by using both the VPF test and the ExacTrac optical tracking system to evaluate the couch position. We showed that the VPF test was in agreement with the ExacTrac optical tracking system within a root-mean-square value of 0.07 mm for both the lateral and longitudinal directions. In conclusion, we demonstrated the VPF test can determine the offset between a 2D detector array and the radiation isocenter with submillimeter accuracy. Until now, no method to locate the radiation isocenter using a 2D detector array has been able to achieve such accuracy.

  3. Privacy-Preserving Accountable Accuracy Management Systems (PAAMS)

    NASA Astrophysics Data System (ADS)

    Thomas, Roshan K.; Sandhu, Ravi; Bertino, Elisa; Arpinar, Budak; Xu, Shouhuai

    We argue for the design of “Privacy-preserving Accountable Accuracy Management Systems (PAAMS)”. The designs of such systems recognize from the onset that accuracy, accountability, and privacy management are intertwined. As such, these systems have to dynamically manage the tradeoffs between these (often conflicting) objectives. For example, accuracy in such systems can be improved by providing better accountability links between structured and unstructured information. Further, accuracy may be enhanced if access to private information is allowed in controllable and accountable ways. Our proposed approach involves three key elements. First, a model to link unstructured information such as that found in email, image and document repositories with structured information such as that in traditional databases. Second, a model for accuracy management and entity disambiguation by proactively preventing, detecting and tracing errors in information bases. Third, a model to provide privacy-governed operation as accountability and accuracy are managed.

  4. Tracking accuracy assessment for concentrator photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Norton, Matthew S. H.; Anstey, Ben; Bentley, Roger W.; Georghiou, George E.

    2010-10-01

    The accuracy to which a concentrator photovoltaic (CPV) system can track the sun is an important parameter that influences a number of measurements that indicate the performance efficiency of the system. This paper presents work carried out into determining the tracking accuracy of a CPV system, and illustrates the steps involved in gaining an understanding of the tracking accuracy. A Trac-Stat SL1 accuracy monitor has been used in the determination of pointing accuracy and has been integrated into the outdoor CPV module test facility at the Photovoltaic Technology Laboratories in Nicosia, Cyprus. Results from this work are provided to demonstrate how important performance indicators may be presented, and how the reliability of results is improved through the deployment of such accuracy monitors. Finally, recommendations on the use of such sensors are provided as a means to improve the interpretation of real outdoor performance.

  5. The accuracy of general practitioner workforce projections

    PubMed Central

    2013-01-01

    Background Health workforce projections are important instruments to prevent imbalances in the health workforce. For both the tenability and further development of these projections, it is important to evaluate the accuracy of workforce projections. In the Netherlands, health workforce projections have been done since 2000 to support health workforce planning. What is the accuracy of the techniques of these Dutch general practitioner workforce projections? Methods We backtested the workforce projection model by comparing the ex-post projected number of general practitioners with the observed number of general practitioners between 1998 and 2011. Averages of historical data were used for all elements except for inflow in training. As the required training inflow is the key result of the workforce planning model, and has actually determined past adjustments of training inflow, the accuracy of the model was backtested using the observed training inflow and not an average of historical data to avoid the interference of past policy decisions. The accuracy of projections with different lengths of projection horizon and base period (on which the projections are based) was tested. Results The workforce projection model underestimated the number of active Dutch general practitioners in most years. The mean absolute percentage errors range from 1.9% to 14.9%, with the projections being more accurate in more recent years. Furthermore, projections with a shorter projection horizon have a higher accuracy than those with a longer horizon. Unexpectedly, projections with a shorter base period have a higher accuracy than those with a longer base period. Conclusions According to the results of the present study, forecasting the size of the future workforce did not become more difficult between 1998 and 2011, as we originally expected. Furthermore, the projections with a short projection horizon and a short base period are more accurate than projections with a longer projection

  6. Accuracy of recall of musculoskeletal injuries in elite military personnel: a cross-sectional study.

    PubMed

    Lovalekar, Mita; Abt, John P; Sell, Timothy C; Lephart, Scott M; Pletcher, Erin; Beals, Kim

    2017-12-14

    Self-reported data are often used in research studies among military populations. The accuracy of self-reported musculoskeletal injury data among elite military personnel was assessed for issues with recall. Cross-sectional study. Applied research laboratory at a military installation. A total of 101 subjects participated (age 28.5±5.6 years). Study participants were active duty military personnel, with no conditions that precluded them from full duty. Self-reported and medical record reviewed injuries that occurred during a 1-year period were matched by anatomic location, injury side (for extremity injuries), and injury year and type. The accuracy of recall was estimated as the per cent of medical record reviewed injuries correctly recalled in the self-report. The effect of injury anatomic location, injury type and severity and time since injury, on recall, was also assessed. Injuries were classified as recent (≤4 years since injury) or old injuries (>4 years since injury). Recall proportions were compared using Fisher's exact tests. A total of 374 injuries were extracted from the subjects' medical records. Recall was generally low (12.0%) and was not different between recent and old injuries (P=0.206). Injury location did not affect recall (P=0.418). Recall was higher for traumatic fractures as compared with less severe non-fracture injuries (P values 0.001 to <0.001). Recall for non-fracture injuries was higher for recent as compared with old injuries (P=0.033). This effect of time since injury on recall was not observed for fractures (P=0.522). The results of this study highlight the importance of weighing the advantages and disadvantages of self-reported injury data before their use in research studies in military populations and the need for future research to identify modifiable factors that influence recall. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is

  7. Culture and Probability Judgment Accuracy: The Influence of Holistic Reasoning

    PubMed Central

    Lechuga, Julia; Wiebe, John S.

    2012-01-01

    A well-established phenomenon in the judgment and decision-making tradition is the overconfidence one places in the amount of knowledge that one possesses. Overconfidence or probability judgment accuracy varies not only individually but also across cultures. However, research efforts to explain cross-cultural variations in the overconfidence phenomenon have seldom been made. In Study 1, the authors compared the probability judgment accuracy of U.S. Americans (N = 108) and Mexican participants (N = 100). In Study 2, they experimentally primed culture by randomly assigning English/Spanish bilingual Mexican Americans (N = 195) to response language. Results of both studies replicated the cross-cultural variation of probability judgment accuracy previously observed in other cultural groups. U.S. Americans displayed less overconfidence when compared to Mexicans. These results were then replicated in bilingual participants, when culture was experimentally manipulated with language priming. Holistic reasoning did not account for the cross-cultural variation of overconfidence. Suggestions for future studies are discussed. PMID:22879682

  8. Culture and Probability Judgment Accuracy: The Influence of Holistic Reasoning.

    PubMed

    Lechuga, Julia; Wiebe, John S

    2011-08-01

    A well-established phenomenon in the judgment and decision-making tradition is the overconfidence one places in the amount of knowledge that one possesses. Overconfidence or probability judgment accuracy varies not only individually but also across cultures. However, research efforts to explain cross-cultural variations in the overconfidence phenomenon have seldom been made. In Study 1, the authors compared the probability judgment accuracy of U.S. Americans (N = 108) and Mexican participants (N = 100). In Study 2, they experimentally primed culture by randomly assigning English/Spanish bilingual Mexican Americans (N = 195) to response language. Results of both studies replicated the cross-cultural variation of probability judgment accuracy previously observed in other cultural groups. U.S. Americans displayed less overconfidence when compared to Mexicans. These results were then replicated in bilingual participants, when culture was experimentally manipulated with language priming. Holistic reasoning did not account for the cross-cultural variation of overconfidence. Suggestions for future studies are discussed.

  9. What do we mean by accuracy in geomagnetic measurements?

    USGS Publications Warehouse

    Green, A.W.

    1990-01-01

    High accuracy is what distinguishes measurements made at the world's magnetic observatories from other types of geomagnetic measurements. High accuracy in determining the absolute values of the components of the Earth's magnetic field is essential to studying geomagnetic secular variation and processes at the core mantle boundary, as well as some magnetospheric processes. In some applications of geomagnetic data, precision (or resolution) of measurements may also be important. In addition to accuracy and resolution in the amplitude domain, it is necessary to consider these same quantities in the frequency and space domains. New developments in geomagnetic instruments and communications make real-time, high accuracy, global geomagnetic observatory data sets a real possibility. There is a growing realization in the scientific community of the unique relevance of geomagnetic observatory data to the principal contemporary problems in solid Earth and space physics. Together, these factors provide the promise of a 'renaissance' of the world's geomagnetic observatory system. ?? 1990.

  10. Protocol for diagnostic test accuracy study: the efficacy of screening for common dental diseases by Dental Care Professionals

    PubMed Central

    2013-01-01

    Background The bulk of service delivery in dentistry is delivered by general dental practitioners, when a large proportion of patients who attend regularly are asymptomatic and do not require treatment. This represents a substantial and unnecessary cost, given that it is possible to delegate a range of tasks to dental care professionals, who are a less expensive resource. Screening for the common dental diseases by dental care professionals has the potential to release general dental practitioner’s time and increase the capacity to care for those who don't currently access services. The aim of this study is to compare the diagnostic test accuracy of dental care professionals when screening for dental caries and periodontal disease in asymptomatic adults aged eighteen years of age. Methods/design Ten dental practices across the North-West of England will take part in a diagnostic test accuracy study with 200 consecutive patients in each practice. The dental care professionals will act as the index test and the general dental practitioner will act as the reference test. Consenting asymptomatic patients will enter the study and see either the dental care professionals or general dental practitioner first to remove order effects. Both sets of clinicians will make an assessment of dental caries and periodontal disease and enter their decisions on a record sheet for each participant. The primary outcome measure is the diagnostic test accuracy of the dental care professionals and sensitivity, specificity, positive predictive value and negative predictive values will be reported. A number of clinical factors will be assessed for confounding. Discussion The results of this study will determine whether dental care professionals can screen for the two most prevalent oral diseases. This will inform the literature and is apposite given the recent policy change in the United Kingdom towards direct access. PMID:24053760

  11. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

    Kronenwetter, Jeffrey; Carter, Delano R.; Todirita, Monica; Chu, Donald

    2016-01-01

    The GOES-R magnetometer accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. To achieve this, the sensor itself has better than 1 nT accuracy. Because zero offset and scale factor drift over time, it is also necessary to perform annual calibration maneuvers. To predict performance, we used covariance analysis and attempted to corroborate it with simulations. Although not perfect, the two generally agree and show the expected behaviors. With the annual calibration regimen, these predictions suggest that the magnetometers will meet their accuracy requirements.

  12. Person-Fit Statistics for Joint Models for Accuracy and Speed

    ERIC Educational Resources Information Center

    Fox, Jean-Paul; Marianti, Sukaesi

    2017-01-01

    Response accuracy and response time data can be analyzed with a joint model to measure ability and speed of working, while accounting for relationships between item and person characteristics. In this study, person-fit statistics are proposed for joint models to detect aberrant response accuracy and/or response time patterns. The person-fit tests…

  13. Classification Accuracy of MMPI-2 Validity Scales in the Detection of Pain-Related Malingering: A Known-Groups Study

    ERIC Educational Resources Information Center

    Bianchini, Kevin J.; Etherton, Joseph L.; Greve, Kevin W.; Heinly, Matthew T.; Meyers, John E.

    2008-01-01

    The purpose of this study was to determine the accuracy of "Minnesota Multiphasic Personality Inventory" 2nd edition (MMPI-2; Butcher, Dahlstrom, Graham, Tellegen, & Kaemmer, 1989) validity indicators in the detection of malingering in clinical patients with chronic pain using a hybrid clinical-known groups/simulator design. The…

  14. How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study.

    PubMed

    Sallent, A; Vicente, M; Reverté, M M; Lopez, A; Rodríguez-Baeza, A; Pérez-Domínguez, M; Velez, R

    2017-10-01

    To assess the accuracy of patient-specific instruments (PSIs) versus standard manual technique and the precision of computer-assisted planning and PSI-guided osteotomies in pelvic tumour resection. CT scans were obtained from five female cadaveric pelvises. Five osteotomies were designed using Mimics software: sacroiliac, biplanar supra-acetabular, two parallel iliopubic and ischial. For cases of the left hemipelvis, PSIs were designed to guide standard oscillating saw osteotomies and later manufactured using 3D printing. Osteotomies were performed using the standard manual technique in cases of the right hemipelvis. Post-resection CT scans were quantitatively analysed. Student's t -test and Mann-Whitney U test were used. Compared with the manual technique, PSI-guided osteotomies improved accuracy by a mean 9.6 mm (p < 0.008) in the sacroiliac osteotomies, 6.2 mm (p < 0.008) and 5.8 mm (p < 0.032) in the biplanar supra-acetabular, 3 mm (p < 0.016) in the ischial and 2.2 mm (p < 0.032) and 2.6 mm (p < 0.008) in the parallel iliopubic osteotomies, with a mean linear deviation of 4.9 mm (p < 0.001) for all osteotomies. Of the manual osteotomies, 53% (n = 16) had a linear deviation > 5 mm and 27% (n = 8) were > 10 mm. In the PSI cases, deviations were 10% (n = 3) and 0 % (n = 0), respectively. For angular deviation from pre-operative plans, we observed a mean improvement of 7.06° (p < 0.001) in pitch and 2.94° (p < 0.001) in roll, comparing PSI and the standard manual technique. In an experimental study, computer-assisted planning and PSIs improved accuracy in pelvic tumour resections, bringing osteotomy results closer to the parameters set in pre-operative planning, as compared with standard manual techniques. Cite this article : A. Sallent, M. Vicente, M. M. Reverté, A. Lopez, A. Rodríguez-Baeza, M. Pérez-Domínguez, R. Velez. How 3D patient-specific instruments improve accuracy of pelvic bone tumour resection in a cadaveric study. Bone Joint Res 2017

  15. The effects of stress on singing voice accuracy.

    PubMed

    Larrouy-Maestri, Pauline; Morsomme, Dominique

    2014-01-01

    The quality of a music performance can be lessened or enhanced if the performer experiences stressful conditions. In addition, the quality of a sung performance requires control of the fundamental frequency of the voice, which is particularly sensitive to stress. The present study aimed to clarify the effects of stress on singing voice accuracy. Thirty-one music students were recorded in a stressful condition (ie, a music examination) and a nonstressful condition. Two groups were defined according to the challenge level of the music examination (first and second music levels). Measurements were made by self-reported state anxiety (CSAI-2R questionnaire) and by observing heart rate activity (electrocardiogram) during each performance. In addition, the vocal accuracy of the sung performances was objectively analyzed. As expected, state anxiety and heart rate were significantly higher on the day of the music examination than in the nonstressful condition for all the music students. However, the effect of stress was positive for the first-year students but negative for the second-year students, for whom the music examination was particularly challenging. In addition, highly significant correlations were found between the intensity of cognitive symptoms and the vocal accuracy criteria. This study highlights the contrasting effects of stress on singing voice accuracy but also the need to consider the challenge level and perception of the symptoms in experimental and pedagogical settings. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  16. The diagnostic performance of perfusion MRI for differentiating glioma recurrence from pseudoprogression: A meta-analysis.

    PubMed

    Wan, Bing; Wang, Siqi; Tu, Mengqi; Wu, Bo; Han, Ping; Xu, Haibo

    2017-03-01

    The purpose of this meta-analysis was to evaluate the diagnostic accuracy of perfusion magnetic resonance imaging (MRI) as a method for differentiating glioma recurrence from pseudoprogression. The PubMed, Embase, Cochrane Library, and Chinese Biomedical databases were searched comprehensively for relevant studies up to August 3, 2016 according to specific inclusion and exclusion criteria. The quality of the included studies was assessed according to the quality assessment of diagnostic accuracy studies (QUADAS-2). After performing heterogeneity and threshold effect tests, pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated. Publication bias was evaluated visually by a funnel plot and quantitatively using Deek funnel plot asymmetry test. The area under the summary receiver operating characteristic curve was calculated to demonstrate the diagnostic performance of perfusion MRI. Eleven studies covering 416 patients and 418 lesions were included in this meta-analysis. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.88 (95% confidence interval [CI] 0.84-0.92), 0.77 (95% CI 0.69-0.84), 3.93 (95% CI 2.83-5.46), 0.16 (95% CI 0.11-0.22), and 27.17 (95% CI 14.96-49.35), respectively. The area under the summary receiver operating characteristic curve was 0.8899. There was no notable publication bias. Sensitivity analysis showed that the meta-analysis results were stable and credible. While perfusion MRI is not the ideal diagnostic method for differentiating glioma recurrence from pseudoprogression, it could improve diagnostic accuracy. Therefore, further research on combining perfusion MRI with other imaging modalities is warranted.

  17. Quality and accuracy assessment of nutrition information on the Web for cancer prevention.

    PubMed

    Shahar, Suzana; Shirley, Ng; Noah, Shahrul A

    2013-01-01

    This study aimed to assess the quality and accuracy of nutrition information about cancer prevention available on the Web. The keywords 'nutrition  +  diet  +  cancer  +  prevention' were submitted to the Google search engine. Out of 400 websites evaluated, 100 met the inclusion and exclusion criteria and were selected as the sample for the assessment of quality and accuracy. Overall, 54% of the studied websites had low quality, 48 and 57% had no author's name or information, respectively, 100% were not updated within 1 month during the study period and 86% did not have the Health on the Net seal. When the websites were assessed for readability using the Flesch Reading Ease test, nearly 44% of the websites were categorised as 'quite difficult'. With regard to accuracy, 91% of the websites did not precisely follow the latest WCRF/AICR 2007 recommendation. The quality scores correlated significantly with the accuracy scores (r  =  0.250, p  <  0.05). Professional websites (n  =  22) had the highest mean quality scores, whereas government websites (n  =  2) had the highest mean accuracy scores. The quality of the websites selected in this study was not satisfactory, and there is great concern about the accuracy of the information being disseminated.

  18. Influence of cue word perceptual information on metamemory accuracy in judgement of learning.

    PubMed

    Hu, Xiao; Liu, Zhaomin; Li, Tongtong; Luo, Liang

    2016-01-01

    Previous studies have suggested that perceptual information regarding to-be-remembered words in the study phase affects the accuracy of judgement of learning (JOL). However, few have investigated whether the perceptual information in the JOL phase influences JOL accuracy. This study examined the influence of cue word perceptual information in the JOL phase on immediate and delayed JOL accuracy through changes in cue word font size. In Experiment 1, large-cue word pairs had significantly higher mean JOL magnitude than small-cue word pairs in immediate JOLs and higher relative accuracy than small-cue pairs in delayed JOLs, but font size had no influence on recall performance. Experiment 2 increased the JOL time, and mean JOL magnitude did not reliably differ for large-cue compared with small-cue pairs in immediate JOLs. However, the influence on relative accuracy still existed in delayed JOLs. Experiment 3 increased the familiarity of small-cue words in the delayed JOL phase by adding a lexical decision task. The results indicated that cue word font size no longer affected relative accuracy in delayed JOLs. The three experiments in our study indicated that the perceptual information regarding cue words in the JOL phase affects immediate and delayed JOLs in different ways.

  19. Accuracy of clinical diagnosis of Parkinson disease: A systematic review and meta-analysis.

    PubMed

    Rizzo, Giovanni; Copetti, Massimiliano; Arcuti, Simona; Martino, Davide; Fontana, Andrea; Logroscino, Giancarlo

    2016-02-09

    To evaluate the diagnostic accuracy of clinical diagnosis of Parkinson disease (PD) reported in the last 25 years by a systematic review and meta-analysis. We searched for articles published between 1988 and August 2014. Studies were included if reporting diagnostic parameters regarding clinical diagnosis of PD or crude data. The selected studies were subclassified based on different study setting, type of test diagnosis, and gold standard. Bayesian meta-analyses of available data were performed. We selected 20 studies, including 11 using pathologic examination as gold standard. Considering only these 11 studies, the pooled diagnostic accuracy was 80.6% (95% credible interval [CrI] 75.2%-85.3%). Accuracy was 73.8% (95% CrI 67.8%-79.6%) for clinical diagnosis performed mainly by nonexperts. Accuracy of clinical diagnosis performed by movement disorders experts rose from 79.6% (95% CrI 46%-95.1%) of initial assessment to 83.9% (95% CrI 69.7%-92.6%) of refined diagnosis after follow-up. Using UK Parkinson's Disease Society Brain Bank Research Center criteria, the pooled diagnostic accuracy was 82.7% (95% CrI 62.6%-93%). The overall validity of clinical diagnosis of PD is not satisfying. The accuracy did not significantly improve in the last 25 years, particularly in the early stages of disease, where response to dopaminergic treatment is less defined and hallmarks of alternative diagnoses such as atypical parkinsonism may not have emerged. Misclassification rate should be considered to calculate the sample size both in observational studies and randomized controlled trials. Imaging and biomarkers are urgently needed to improve the accuracy of clinical diagnosis in vivo. © 2016 American Academy of Neurology.

  20. Executive Processes, Memory Accuracy, and Memory Monitoring: An Aging and Individual Difference Analysis

    ERIC Educational Resources Information Center

    Rhodes, M.G.; Kelley, C.M.

    2005-01-01

    The current study examined the neuropsychological correlates of memory accuracy in older and younger adults. Participants were tested in a memory monitoring paradigm developed by Koriat and Goldsmith (1996), which permits separate assessments of the accuracy of responses generated during retrieval and the accuracy of monitoring those responses.…

  1. Simultaneous inter-arm and inter-leg systolic blood pressure differences to diagnose peripheral artery disease: a diagnostic accuracy study.

    PubMed

    Herráiz-Adillo, Ángel; Soriano-Cano, Alba; Martínez-Hortelano, José Alberto; Garrido-Miguel, Miriam; Mariana-Herráiz, Julián Ángel; Martínez-Vizcaíno, Vicente; Notario-Pacheco, Blanca

    2018-04-01

    Inter-arm systolic blood pressure differences (IASBPD) and inter-leg systolic blood pressure differences (ILSBPD) have arisen as potential tools to detect peripheral artery disease (PAD) and individuals at high cardiovascular risk. This study aims to evaluate the diagnostic accuracy of IASBPD and ILSBPD to detect PAD, and whether IASBPD or ILSBPD improves diagnostic accuracy of the oscillometric ankle-brachial index (ABI). In this prospective study, eligible for inclusion were consecutive adults, with at least one of the following cardiovascular risk factors: diabetes, dyslipidemia, hypertension, smoking habit or age ≥65. IASBPD, ILSBPD and ankle-brachial index (ABI) were measured in all participants through four-limb simultaneous oscillometric measurements and compared with Doppler ABI (reference test, positive cut-off: ≤ 0.9). Of 171 subjects included, PAD was confirmed in 23 and excluded in 148. Thirteen and 38 subjects had IASBPD and ILSBPD ≥10 mmHg, respectively. Pearson correlation with Doppler ABI of IASBPD and ILSBPD was 0.073 (P = .343) and -0.628 (P < .001), respectively. Diagnostic accuracy of an ILSBPD ≥10 mmHg to detect PAD was: sensitivity = 69.6% (95%CI = 48.6-90.5), specificity = 85.1% (79.1-91.2), diagnostic odds ratio (dOR) = 13.1 (4.8-35.5) and area under ROC curve (AUC) = 0.765 (0.616-0.915). IASBPD had an AUC = 0.532 (0.394-0.669), and oscillometric ABI had an AUC = 0.977 (0.950-1.000). The addition of ILSBPD to oscillometric ABI reduced dOR from 174.0 (38.3-789.9) to 34.4 (9.5-125.1). Similarly, the addition of IASBPD reduced dOR to 49.3 (14.6-167.0). In a Primary Care population with ≥1 cardiovascular risk factors, ILSBPD showed acceptable diagnostic accuracy for PAD, whilst IASBPD accuracy was negligible. However, the combination of ILSBPD (or IASBPD) with oscillometric ABI did not improve the ability to detect PAD. Thus, oscillometer ABI seems to be preferable to detect PAD and individuals

  2. Accuracy of five intraoral scanners compared to indirect digitalization.

    PubMed

    Güth, Jan-Frederik; Runkel, Cornelius; Beuer, Florian; Stimmelmayr, Michael; Edelhoff, Daniel; Keul, Christine

    2017-06-01

    Direct and indirect digitalization offer two options for computer-aided design (CAD)/ computer-aided manufacturing (CAM)-generated restorations. The aim of this study was to evaluate the accuracy of different intraoral scanners and compare them to the process of indirect digitalization. A titanium testing model was directly digitized 12 times with each intraoral scanner: (1) CS 3500 (CS), (2) Zfx Intrascan (ZFX), (3) CEREC AC Bluecam (BLU), (4) CEREC AC Omnicam (OC) and (5) True Definition (TD). As control, 12 polyether impressions were taken and the referring plaster casts were digitized indirectly with the D-810 laboratory scanner (CON). The accuracy (trueness/precision) of the datasets was evaluated by an analysing software (Geomagic Qualify 12.1) using a "best fit alignment" of the datasets with a highly accurate reference dataset of the testing model, received from industrial computed tomography. Direct digitalization using the TD showed the significant highest overall "trueness", followed by CS. Both performed better than CON. BLU, ZFX and OC showed higher differences from the reference dataset than CON. Regarding the overall "precision", the CS 3500 intraoral scanner and the True Definition showed the best performance. CON, BLU and OC resulted in significantly higher precision than ZFX did. Within the limitations of this in vitro study, the accuracy of the ascertained datasets was dependent on the scanning system. The direct digitalization was not superior to indirect digitalization for all tested systems. Regarding the accuracy, all tested intraoral scanning technologies seem to be able to reproduce a single quadrant within clinical acceptable accuracy. However, differences were detected between the tested systems.

  3. Fourth-grade children’s dietary reporting accuracy by meal component: Results from a validation study that manipulated retention interval and prompts

    PubMed Central

    Baxter, Suzanne D.; Hitchcock, David B.; Royer, Julie A.; Smith, Albert F.; Guinn, Caroline H.

    2017-01-01

    We examined reporting accuracy by meal component (beverage, bread, breakfast meat, combination entrée, condiment, dessert, entrée, fruit, vegetable) with validation-study data on 455 fourth-grade children (mean age = 9.92 ± 0.41 years) observed eating school meals and randomized to one of eight dietary recall conditions (two retention intervals [short, long] crossed with four prompts [forward, meal-name, open, reverse]). Accuracy category (match [observed and reported], omission [observed but unreported], intrusion [unobserved but reported]) was a polytomous nominal item response variable. We fit a multilevel cumulative logit model with item variables meal component and serving period (breakfast, lunch) and child variables retention interval, prompt and sex. Significant accuracy category predictors were meal component (p < 0.0003), retention interval (p < 0.0003), meal-component × serving-period (p < 0.0003) and meal-component × retention-interval (p = 0.001). The relationship of meal component and accuracy category was much stronger for lunch than breakfast. For lunch, beverages were matches more often, omissions much less often and intrusions more often than expected under independence; fruits and desserts were omissions more often. For the meal-component × retention-interval interaction, for the short retention interval, beverages were intrusions much more often but combination entrées and condiments were intrusions less often; for the long retention interval, beverages were matches more often and omissions less often but fruits were matches less often. Accuracy for each meal component appeared better with the short than long retention interval. For lunch and for the short retention interval, children’s reporting was most accurate for entrée and combination entrée meal components, whereas it was least accurate for vegetable and fruit meal components. Results have implications for conclusions of studies and interventions assessed with dietary recalls

  4. Development of a novel empathy-related video-feedback intervention to improve empathic accuracy of nursing students: A pilot study.

    PubMed

    Lobchuk, Michelle; Halas, Gayle; West, Christina; Harder, Nicole; Tursunova, Zulfiya; Ramraj, Chantal

    2016-11-01

    Stressed family carers engage in health-risk behaviours that can lead to chronic illness. Innovative strategies are required to bolster empathic dialogue skills that impact nursing student confidence and sensitivity in meeting carers' wellness needs. To report on the development and evaluation of a promising empathy-related video-feedback intervention and its impact on student empathic accuracy on carer health risk behaviours. A pilot quasi-experimental design study with eight pairs of 3rd year undergraduate nursing students and carers. Students participated in perspective-taking instructional and practice sessions, and a 10-minute video-recorded dialogue with carers followed by a video-tagging task. Quantitative and qualitative approaches helped us to evaluate the recruitment protocol, capture participant responses to the intervention and study tools, and develop a tool to assess student empathic accuracy. The instructional and practice sessions increased student self-awareness of biases and interest in learning empathy by video-tagging feedback. Carers felt that students were 'non-judgmental', inquisitive, and helped them to 'gain new insights' that fostered ownership to change their health-risk behaviour. There was substantial Fleiss Kappa agreement among four raters across five dyads and 67 tagged instances. In general, students and carers evaluated the intervention favourably. The results suggest areas of improvement to the recruitment protocol, perspective-taking instructions, video-tagging task, and empathic accuracy tool. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Accuracy of tracking forest machines with GPS

    Treesearch

    M.W. Veal; S.E. Taylor; T.P. McDonald; D.K. McLemore; M.R. Dunn

    2001-01-01

    This paper describes the results of a study that measured the accuracy of using GPS to track movement of forest machines. Two different commercially available GPS receivers (Trimble ProXR and GeoExplorer II) were used to track\\r\

  6. Evaluating arguments during instigations of defence motivation and accuracy motivation.

    PubMed

    Liu, Cheng-Hong

    2017-05-01

    When people evaluate the strength of an argument, their motivations are likely to influence the evaluation. However, few studies have specifically investigated the influences of motivational factors on argument evaluation. This study examined the effects of defence and accuracy motivations on argument evaluation. According to the compatibility between the advocated positions of arguments and participants' prior beliefs and the objective strength of arguments, participants evaluated four types of arguments: compatible-strong, compatible-weak, incompatible-strong, and incompatible-weak arguments. Experiment 1 revealed that participants possessing a high defence motivation rated compatible-weak arguments as stronger and incompatible-strong ones as weaker than participants possessing a low defence motivation. However, the strength ratings between the high and low defence groups regarding both compatible-strong and incompatible-weak arguments were similar. Experiment 2 revealed that when participants possessed a high accuracy motivation, they rated compatible-weak arguments as weaker and incompatible-strong ones as stronger than when they possessed a low accuracy motivation. However, participants' ratings on both compatible-strong and incompatible-weak arguments were similar when comparing high and low accuracy conditions. The results suggest that defence and accuracy motivations are two major motives influencing argument evaluation. However, they primarily influence the evaluation results for compatible-weak and incompatible-strong arguments, but not for compatible-strong and incompatible-weak arguments. © 2016 The British Psychological Society.

  7. Evaluating Behavioral Self-Monitoring with Accuracy Training for Changing Computer Work Postures

    ERIC Educational Resources Information Center

    Gravina, Nicole E.; Loewy, Shannon; Rice, Anna; Austin, John

    2013-01-01

    The primary purpose of this study was to replicate and extend a study by Gravina, Austin, Schroedter, and Loewy (2008). A similar self-monitoring procedure, with the addition of self-monitoring accuracy training, was implemented to increase the percentage of observations in which participants worked in neutral postures. The accuracy training…

  8. Accuracy of line probe assays for the diagnosis of pulmonary and multidrug-resistant tuberculosis: a systematic review and meta-analysis

    PubMed Central

    Cudahy, Patrick G.T; Schumacher, Samuel G.; Steingart, Karen R.; Pai, Madhukar; Denkinger, Claudia M.

    2017-01-01

    Only 25% of multidrug-resistant tuberculosis (MDR-TB) cases are currently diagnosed. Line probe assays (LPAs) enable rapid drug-susceptibility testing for rifampicin (RIF) and isoniazid (INH) resistance and Mycobacterium tuberculosis detection. Genotype MTBDRplusV1 was WHO-endorsed in 2008 but newer LPAs have since been developed. This systematic review evaluated three LPAs: Hain Genotype MTBDRplusV1, MTBDRplusV2 and Nipro NTM+MDRTB. Study quality was assessed with QUADAS-2. Bivariate random-effects meta-analyses were performed for direct and indirect testing. Results for RIF and INH resistance were compared to phenotypic and composite (incorporating sequencing) reference standards. M. tuberculosis detection results were compared to culture. 74 unique studies were included. For RIF resistance (21 225 samples), pooled sensitivity and specificity (with 95% confidence intervals) were 96.7% (95.6–97.5%) and 98.8% (98.2–99.2%). For INH resistance (20 954 samples), pooled sensitivity and specificity were 90.2% (88.2–91.9%) and 99.2% (98.7–99.5%). Results were similar for direct and indirect testing and across LPAs. Using a composite reference standard, specificity increased marginally. For M. tuberculosis detection (3451 samples), pooled sensitivity was 94% (89.4–99.4%) for smear-positive specimens and 44% (20.2–71.7%) for smear-negative specimens. In patients with pulmonary TB, LPAs have high sensitivity and specificity for RIF resistance and high specificity and good sensitivity for INH resistance. This meta-analysis provides evidence for policy and practice. PMID:28100546

  9. Interactive visualisation for interpreting diagnostic test accuracy study results.

    PubMed

    Fanshawe, Thomas R; Power, Michael; Graziadio, Sara; Ordóñez-Mena, José M; Simpson, John; Allen, Joy

    2018-02-01

    Information about the performance of diagnostic tests is typically presented in the form of measures of test accuracy such as sensitivity and specificity. These measures may be difficult to translate directly into decisions about patient treatment, for which information presented in the form of probabilities of disease after a positive or a negative test result may be more useful. These probabilities depend on the prevalence of the disease, which is likely to vary between populations. This article aims to clarify the relationship between pre-test (prevalence) and post-test probabilities of disease, and presents two free, online interactive tools to illustrate this relationship. These tools allow probabilities of disease to be compared with decision thresholds above and below which different treatment decisions may be indicated. They are intended to help those involved in communicating information about diagnostic test performance and are likely to be of benefit when teaching these concepts. A substantive example is presented using C reactive protein as a diagnostic marker for bacterial infection in the older adult population. The tools may also be useful for manufacturers of clinical tests in planning product development, for authors of test evaluation studies to improve reporting and for users of test evaluations to facilitate interpretation and application of the results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Accuracy of a Computer-Aided Surgical Simulation (CASS) Protocol for Orthognathic Surgery: A Prospective Multicenter Study

    PubMed Central

    Hsu, Sam Sheng-Pin; Gateno, Jaime; Bell, R. Bryan; Hirsch, David L.; Markiewicz, Michael R.; Teichgraeber, John F.; Zhou, Xiaobo; Xia, James J.

    2012-01-01

    Purpose The purpose of this prospective multicenter study was to assess the accuracy of a computer-aided surgical simulation (CASS) protocol for orthognathic surgery. Materials and Methods The accuracy of the CASS protocol was assessed by comparing planned and postoperative outcomes of 65 consecutive patients enrolled from 3 centers. Computer-generated surgical splints were used for all patients. For the genioplasty, one center utilized computer-generated chin templates to reposition the chin segment only for patients with asymmetry. Standard intraoperative measurements were utilized without the chin templates for the remaining patients. The primary outcome measurements were linear and angular differences for the maxilla, mandible and chin when the planned and postoperative models were registered at the cranium. The secondary outcome measurements were: maxillary dental midline difference between the planned and postoperative positions; and linear and angular differences of the chin segment between the groups with and without the use of the template. The latter was measured when the planned and postoperative models were registered at mandibular body. Statistical analyses were performed, and the accuracy was reported using root mean square deviation (RMSD) and Bland and Altman's method for assessing measurement agreement. Results In the primary outcome measurements, there was no statistically significant difference among the 3 centers for the maxilla and mandible. The largest RMSD was 1.0mm and 1.5° for the maxilla, and 1.1mm and 1.8° for the mandible. For the chin, there was a statistically significant difference between the groups with and without the use of the chin template. The chin template group showed excellent accuracy with largest positional RMSD of 1.0mm and the largest orientational RSMD of 2.2°. However, larger variances were observed in the group not using the chin template. This was significant in anteroposterior and superoinferior directions, as in

  11. Accuracy of body weight perception and obesity among Chinese Americans.

    PubMed

    Liu, Shan; Fu, Mei R; Hu, Sophia H; Wang, Vincent Y; Crupi, Robert; Qiu, Jeanna M; Cleland, Chuck; D'Eramo Melkus, Gail

    2016-09-01

    Accuracy of body weight perception is an individual's perception of their body weight in comparison with actual body weight and is associated with weight-related behaviors. Chinese Americans have increased risk for obesity but no studies have examined accuracy of body weight perception. This study was a descriptive and cross-sectional study, which was conducted in a community health center in New York. Study subjects were all Chinese-American adults. Demographic information, accuracy of perception of body weight, anthropometric measures (weight, height, body mass index [BMI], waist circumference [WC], hip circumference [HC], weight to height ratio, weight to hip ratio), fasting plasma glucose (FPG), glycosylated hemoglobin (HbA1C) and obesity-related diseases (hypertension, diabetes, heart disease, and stroke) were assessed. A total of 162 Chinese Americans were recruited. 52 subjects (32%) did not perceive body weight correctly: 32 subjects had underestimation and 20 subjects had overestimation of body weight. Significant differences were found among subjects in the three groups of different accuracy of body weight perception in terms of gender (p=0.003), age (p=0.003), education years (p=0.047), WC (p<0.001), HC (p≤0.001), weight/height ratio (p=0.001), and BMI (p<0.001). Accuracy of perception of body weight significantly predicted WC (p<0.001), HC (p<0.001), weight to height ratio (p=0.001), BMI (p<0.001) and weight (<0.001) even after controlling for all demographic factors. The study identified that around one-third of Chinese Americans did not perceive their body weight correctly. Intervention studies for obesity management in Chinese Americans should address gender difference, target on older subjects, and focus on educating the normal values and significances of WC, HC and HbA1C among Chinese Americans. Copyright © 2015 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  12. Urban Land Cover Mapping Accuracy Assessment - A Cost-benefit Analysis Approach

    NASA Astrophysics Data System (ADS)

    Xiao, T.

    2012-12-01

    One of the most important components in urban land cover mapping is mapping accuracy assessment. Many statistical models have been developed to help design simple schemes based on both accuracy and confidence levels. It is intuitive that an increased number of samples increases the accuracy as well as the cost of an assessment. Understanding cost and sampling size is crucial in implementing efficient and effective of field data collection. Few studies have included a cost calculation component as part of the assessment. In this study, a cost-benefit sampling analysis model was created by combining sample size design and sampling cost calculation. The sampling cost included transportation cost, field data collection cost, and laboratory data analysis cost. Simple Random Sampling (SRS) and Modified Systematic Sampling (MSS) methods were used to design sample locations and to extract land cover data in ArcGIS. High resolution land cover data layers of Denver, CO and Sacramento, CA, street networks, and parcel GIS data layers were used in this study to test and verify the model. The relationship between the cost and accuracy was used to determine the effectiveness of each sample method. The results of this study can be applied to other environmental studies that require spatial sampling.

  13. Phenomenological reports diagnose accuracy of eyewitness identification decisions.

    PubMed

    Palmer, Matthew A; Brewer, Neil; McKinnon, Anna C; Weber, Nathan

    2010-02-01

    This study investigated whether measuring the phenomenology of eyewitness identification decisions aids evaluation of their accuracy. Witnesses (N=502) viewed a simulated crime and attempted to identify two targets from lineups. A divided attention manipulation during encoding reduced the rate of remember (R) correct identifications, but not the rates of R foil identifications or know (K) judgments in the absence of recollection (i.e., K/[1-R]). Both RK judgments and recollection ratings (a novel measure of graded recollection) distinguished correct from incorrect positive identifications. However, only recollection ratings improved accuracy evaluation after identification confidence was taken into account. These results provide evidence that RK judgments for identification decisions function in a similar way as for recognition decisions; are consistent with the notion of graded recollection; and indicate that measures of phenomenology can enhance the evaluation of identification accuracy. Copyright 2009 Elsevier B.V. All rights reserved.

  14. Systematic bias of correlation coefficient may explain negative accuracy of genomic prediction.

    PubMed

    Zhou, Yao; Vales, M Isabel; Wang, Aoxue; Zhang, Zhiwu

    2017-09-01

    Accuracy of genomic prediction is commonly calculated as the Pearson correlation coefficient between the predicted and observed phenotypes in the inference population by using cross-validation analysis. More frequently than expected, significant negative accuracies of genomic prediction have been reported in genomic selection studies. These negative values are surprising, given that the minimum value for prediction accuracy should hover around zero when randomly permuted data sets are analyzed. We reviewed the two common approaches for calculating the Pearson correlation and hypothesized that these negative accuracy values reflect potential bias owing to artifacts caused by the mathematical formulas used to calculate prediction accuracy. The first approach, Instant accuracy, calculates correlations for each fold and reports prediction accuracy as the mean of correlations across fold. The other approach, Hold accuracy, predicts all phenotypes in all fold and calculates correlation between the observed and predicted phenotypes at the end of the cross-validation process. Using simulated and real data, we demonstrated that our hypothesis is true. Both approaches are biased downward under certain conditions. The biases become larger when more fold are employed and when the expected accuracy is low. The bias of Instant accuracy can be corrected using a modified formula. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Diagnostic accuracy of laparoscopy following computed tomography (CT) scanning for assessing the resectability with curative intent in pancreatic and periampullary cancer.

    PubMed

    Allen, Victoria B; Gurusamy, Kurinchi Selvan; Takwoingi, Yemisi; Kalia, Amun; Davidson, Brian R

    2016-07-06

    Surgical resection is the only potentially curative treatment for pancreatic and periampullary cancer. A considerable proportion of patients undergo unnecessary laparotomy because of underestimation of the extent of the cancer on computed tomography (CT) scanning. Laparoscopy can detect metastases not visualised on CT scanning, enabling better assessment of the spread of cancer (staging of cancer). This is an update to a previous Cochrane Review published in 2013 evaluating the role of diagnostic laparoscopy in assessing the resectability with curative intent in people with pancreatic and periampullary cancer. To determine the diagnostic accuracy of diagnostic laparoscopy performed as an add-on test to CT scanning in the assessment of curative resectability in pancreatic and periampullary cancer. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, EMBASE via OvidSP (from inception to 15 May 2016), and Science Citation Index Expanded (from 1980 to 15 May 2016). We included diagnostic accuracy studies of diagnostic laparoscopy in people with potentially resectable pancreatic and periampullary cancer on CT scan, where confirmation of liver or peritoneal involvement was by histopathological examination of suspicious (liver or peritoneal) lesions obtained at diagnostic laparoscopy or laparotomy. We accepted any criteria of resectability used in the studies. We included studies irrespective of language, publication status, or study design (prospective or retrospective). We excluded case-control studies. Two review authors independently performed data extraction and quality assessment using the QUADAS-2 tool. The specificity of diagnostic laparoscopy in all studies was 1 because there were no false positives since laparoscopy and the reference standard are one and the same if histological examination after diagnostic laparoscopy is positive. The sensitivities were therefore meta-analysed using a univariate random-effects logistic

  16. Consider the source: Children link the accuracy of text-based sources to the accuracy of the author.

    PubMed

    Vanderbilt, Kimberly E; Ochoa, Karlena D; Heilbrun, Jayd

    2018-05-06

    The present research investigated whether young children link the accuracy of text-based information to the accuracy of its author. Across three experiments, three- and four-year-olds (N = 231) received information about object labels from accurate and inaccurate sources who provided information both in text and verbally. Of primary interest was whether young children would selectively rely on information provided by more accurate sources, regardless of the form in which the information was communicated. Experiment 1 tested children's trust in text-based information (e.g., books) written by an author with a history of either accurate or inaccurate verbal testimony and found that children showed greater trust in books written by accurate authors. Experiment 2 replicated the findings of Experiment 1 and extended them by showing that children's selective trust in more accurate text-based sources was not dependent on experience trusting or distrusting the author's verbal testimony. Experiment 3 investigated this understanding in reverse by testing children's trust in verbal testimony communicated by an individual who had authored either accurate or inaccurate text-based information. Experiment 3 revealed that children showed greater trust in individuals who had authored accurate rather than inaccurate books. Experiment 3 also demonstrated that children used the accuracy of text-based sources to make inferences about the mental states of the authors. Taken together, these results suggest children do indeed link the reliability of text-based sources to the reliability of the author. Statement of Contribution Existing knowledge Children use sources' prior accuracy to predict future accuracy in face-to-face verbal interactions. Children who are just learning to read show increased trust in text bases (vs. verbal) information. It is unknown whether children consider authors' prior accuracy when judging the accuracy of text-based information. New knowledge added by this

  17. Positional and Dimensional Accuracy Assessment of Drone Images Geo-referenced with Three Different GPSs

    NASA Astrophysics Data System (ADS)

    Cao, C.; Lee, X.; Xu, J.

    2017-12-01

    Unmanned Aerial Vehicles (UAVs) or drones have been widely used in environmental, ecological and engineering applications in recent years. These applications require assessment of positional and dimensional accuracy. In this study, positional accuracy refers to the accuracy of the latitudinal and longitudinal coordinates of locations on the mosaicked image in reference to the coordinates of the same locations measured by a Global Positioning System (GPS) in a ground survey, and dimensional accuracy refers to length and height of a ground target. Here, we investigate the effects of the number of Ground Control Points (GCPs) and the accuracy of the GPS used to measure the GCPs on positional and dimensional accuracy of a drone 3D model. Results show that using on-board GPS and a hand-held GPS produce a positional accuracy on the order of 2-9 meters. In comparison, using a differential GPS with high accuracy (30 cm) improves the positional accuracy of the drone model by about 40 %. Increasing the number of GCPs can compensate for the uncertainty brought by the GPS equipment with low accuracy. In terms of the dimensional accuracy of the drone model, even with the use of a low resolution GPS onboard the vehicle, the mean absolute errors are only 0.04 m for height and 0.10 m for length, which are well suited for some applications in precision agriculture and in land survey studies.

  18. Assessing and Ensuring GOES-R Magnetometer Accuracy

    NASA Technical Reports Server (NTRS)

    Carter, Delano R.; Todirita, Monica; Kronenwetter, Jeffrey; Chu, Donald

    2016-01-01

    The GOES-R magnetometer subsystem accuracy requirement is 1.7 nanoteslas (nT). During quiet times (100 nT), accuracy is defined as absolute mean plus 3 sigma. During storms (300 nT), accuracy is defined as absolute mean plus 2 sigma. Error comes both from outside the magnetometers, e.g. spacecraft fields and misalignments, as well as inside, e.g. zero offset and scale factor errors. Because zero offset and scale factor drift over time, it will be necessary to perform annual calibration maneuvers. To predict performance before launch, we have used Monte Carlo simulations and covariance analysis. Both behave as expected, and their accuracy predictions agree within 30%. With the proposed calibration regimen, both suggest that the GOES-R magnetometer subsystem will meet its accuracy requirements.

  19. Text Difficulty Affects Metacomprehension Accuracy and Knowledge Test Performance in Text Learning

    ERIC Educational Resources Information Center

    Vössing, J.; Stamov-Roßnagel, C.; Heinitz, K.

    2017-01-01

    Metacomprehension as reflected in judgements of one's learning is crucial for self-regulated study, yet their accuracy is often low. We investigated text difficulty as a constraint on metacomprehension accuracy in text learning. A total of 235 participants studied a 10-section expository text and afterwards took a knowledge test. They made…

  20. A material sensitivity study on the accuracy of deformable organ registration using linear biomechanical models

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chi, Y.; Liang, J.; Yan, D.

    2006-02-15

    Model-based deformable organ registration techniques using the finite element method (FEM) have recently been investigated intensively and applied to image-guided adaptive radiotherapy (IGART). These techniques assume that human organs are linearly elastic material, and their mechanical properties are predetermined. Unfortunately, the accurate measurement of the tissue material properties is challenging and the properties usually vary between patients. A common issue is therefore the achievable accuracy of the calculation due to the limited access to tissue elastic material constants. In this study, we performed a systematic investigation on this subject based on tissue biomechanics and computer simulations to establish the relationshipsmore » between achievable registration accuracy and tissue mechanical and organ geometrical properties. Primarily we focused on image registration for three organs: rectal wall, bladder wall, and prostate. The tissue anisotropy due to orientation preference in tissue fiber alignment is captured by using an orthotropic or a transversely isotropic elastic model. First we developed biomechanical models for the rectal wall, bladder wall, and prostate using simplified geometries and investigated the effect of varying material parameters on the resulting organ deformation. Then computer models based on patient image data were constructed, and image registrations were performed. The sensitivity of registration errors was studied by perturbating the tissue material properties from their mean values while fixing the boundary conditions. The simulation results demonstrated that registration error for a subvolume increases as its distance from the boundary increases. Also, a variable associated with material stability was found to be a dominant factor in registration accuracy in the context of material uncertainty. For hollow thin organs such as rectal walls and bladder walls, the registration errors are limited. Given 30% in material

  1. Thoracic injury rule out criteria and NEXUS chest in predicting the risk of traumatic intra-thoracic injuries: A diagnostic accuracy study.

    PubMed

    Safari, Saeed; Radfar, Fatemeh; Baratloo, Alireza

    2018-05-01

    This study aimed to compare the diagnostic accuracy of NEXUS chest and Thoracic Injury Rule out criteria (TIRC) models in predicting the risk of intra-thoracic injuries following blunt multiple trauma. In this diagnostic accuracy study, using the 2 mentioned models, blunt multiple trauma patients over the age of 15 years presenting to emergency department were screened regarding the presence of intra-thoracic injuries that are detectable via chest x-ray and screening performance characteristics of the models were compared. In this study, 3118 patients with the mean (SD) age of 37.4 (16.9) years were studied (57.4% male). Based on TIRC and NEXUS chest, respectively, 1340 (43%) and 1417 (45.4%) patients were deemed in need of radiography performance. Sensitivity, specificity, and positive and negative predictive values of TIRC were 98.95%, 62.70%, 21.19% and 99.83%. These values were 98.61%, 59.94%, 19.97% and 99.76%, for NEXUS chest, respectively. Accuracy of TIRC and NEXUS chest models were 66.04 (95% CI: 64.34-67.70) and 63.50 (95% CI: 61.78-65.19), respectively. TIRC and NEXUS chest models have proper and similar sensitivity in prediction of blunt traumatic intra-thoracic injuries that are detectable via chest x-ray. However, TIRC had a significantly higher specificity in this regard. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Accuracy of stated energy contents of restaurant foods in a multi-site study

    USDA-ARS?s Scientific Manuscript database

    Context National recommendations for prevention and treatment of obesity emphasize reducing energy intake. Foods purchased in restaurants provide approximately 35% of daily energy intake, but the accuracy of information on the energy contents of these foods is unknown. Objective To examine the a...

  3. Does ADHD in adults affect the relative accuracy of metamemory judgments?

    PubMed

    Knouse, Laura E; Paradise, Matthew J; Dunlosky, John

    2006-11-01

    Prior research suggests that individuals with ADHD overestimate their performance across domains despite performing more poorly in these domains. The authors introduce measures of accuracy from the larger realm of judgment and decision making--namely, relative accuracy and calibration--to the study of self-evaluative judgment accuracy in adults with ADHD. Twenty-eight adults with ADHD and 28 matched controls participate in a computer-administered paired-associate learning task and predict their future recall using immediate and delayed judgments of learning (JOLs). Retrospective confidence judgments are also collected. Groups perform equally in terms of judgment magnitude and absolute judgment accuracy as measured by discrepancy scores and calibration curves. Both groups benefit equally from making their JOL at a delay, and the group with ADHD show higher relative accuracy for delayed judgments. Results suggest that under certain circumstances, adults with ADHD can make accurate judgments about their future memory.

  4. Effect of Body-Worn Cameras on EMS Documentation Accuracy: A Pilot Study.

    PubMed

    Ho, Jeffrey D; Dawes, Donald M; McKay, Evan M; Taliercio, Jeremy J; White, Scott D; Woodbury, Blair J; Sandefur, Mark A; Miner, James R

    2017-01-01

    Current Emergency Medical Services (EMS) documentation practices usually occur from memory after an event is over. While this practice is fairly standard, it is unclear if it can introduce significant error. Modern technology has seen the increased use of recorded video by society to more objectively document notable events. Stationary mounted cameras, cell-phone cameras, and law enforcement officer Body-Worn Cameras (BWCs) are increasingly used by society for this purpose. Video used in this way can often clarify or contradict recall from memory. BWCs are currently not widely used by EMS. The hypothesis is that current EMS documentation practices are inaccurate and that BWCs will have a positive effect on documentation accuracy. This prospective, observational study used a convenience sample of paramedics in a simulation lab. The Paramedics wore a BWC and responded to a simulated call of "One Down" (unresponsive from heroin abuse) involving Role Players (RPs). The paramedics received standardized cues from the RPs during the simulation to keep it on track.  The simulation contained many factors of concern (e.g., weapons and drugs in plain view, unattended minors, etc.) and intentional stressors (e.g., distraught family member, uncooperative patient, etc.). Upon completion of the scenario, paramedic documentation occurred from memory on an electronic template.  After initial documentation, paramedics viewed their BWC recording and were allowed to make tabulated changes. Changes were categorized by a priori criteria as minor, moderate, or major.  Ten paramedics participated with an average age of 33.3 years (range 22-43), 8 males and 2 females. The average length of paramedic career experience was 7.7 years (range 2 months to 20 years). There were 71 total documentation changes (7 minor, 51 moderate, 13 major) made after video review. Linear regression (ANCOVA) indicated changes made indirectly correlated with years of experience (coefficient 8.27, 4

  5. Accuracy of self-reported intake of signature foods in a school meal intervention study: comparison between control and intervention period.

    PubMed

    Biltoft-Jensen, Anja; Damsgaard, Camilla Trab; Andersen, Rikke; Ygil, Karin Hess; Andersen, Elisabeth Wreford; Ege, Majken; Christensen, Tue; Sørensen, Louise Bergmann; Stark, Ken D; Tetens, Inge; Thorsen, Anne-Vibeke

    2015-08-28

    Bias in self-reported dietary intake is important when evaluating the effect of dietary interventions, particularly for intervention foods. However, few have investigated this in children, and none have investigated the reporting accuracy of fish intake in children using biomarkers. In a Danish school meal study, 8- to 11-year-old children (n 834) were served the New Nordic Diet (NND) for lunch. The present study examined the accuracy of self-reported intake of signature foods (berries, cabbage, root vegetables, legumes, herbs, potatoes, wild plants, mushrooms, nuts and fish) characterising the NND. Children, assisted by parents, self-reported their diet in a Web-based Dietary Assessment Software for Children during the intervention and control (packed lunch) periods. The reported fish intake by children was compared with their ranking according to fasting whole-blood EPA and DHA concentration and weight percentage using the Spearman correlations and cross-classification. Direct observation of school lunch intake (n 193) was used to score the accuracy of food-reporting as matches, intrusions, omissions and faults. The reporting of all lunch foods had higher percentage of matches compared with the reporting of signature foods in both periods, and the accuracy was higher during the control period compared with the intervention period. Both Spearman's rank correlations and linear mixed models demonstrated positive associations between EPA+DHA and reported fish intake. The direct observations showed that both reported and real intake of signature foods did increase during the intervention period. In conclusion, the self-reported data represented a true increase in the intake of signature foods and can be used to examine dietary intervention effects.

  6. Accuracy vs. Fluency: Which Comes First in ESL Instruction?

    ERIC Educational Resources Information Center

    Ebsworth, Miriam Eisenstein

    1998-01-01

    Discusses the debate over fluency versus accuracy in teaching English-as-a-Second-Language (ESL). Defines fluency and accuracy; examines alternative approaches (meaning first, accuracy first, and accuracy and fluency from the beginning); evaluates the alternatives; and highlights implications for teaching ESL. A sidebar presents an accuracy and…

  7. Does ADHD in Adults Affect the Relative Accuracy of Metamemory Judgments?

    ERIC Educational Resources Information Center

    Knouse, Laura E.; Paradise, Matthew J.; Dunlosky, John

    2006-01-01

    Objective: Prior research suggests that individuals with ADHD overestimate their performance across domains despite performing more poorly in these domains. The authors introduce measures of accuracy from the larger realm of judgment and decision making--namely, relative accuracy and calibration--to the study of self-evaluative judgment accuracy…

  8. Posterior Predictive Checks for Conditional Independence between Response Time and Accuracy

    ERIC Educational Resources Information Center

    Bolsinova, Maria; Tijmstra, Jesper

    2016-01-01

    Conditional independence (CI) between response time and response accuracy is a fundamental assumption of many joint models for time and accuracy used in educational measurement. In this study, posterior predictive checks (PPCs) are proposed for testing this assumption. These PPCs are based on three discrepancy measures reflecting different…

  9. An Evaluation of the Effects of an Oven Timer Study Behavior and Concurrent Completion and Accuracy of Assignments for a First Grade Repeater: A Case Study.

    ERIC Educational Resources Information Center

    Riegelman, Elizabeth D.; And Others

    The effects of an oven timer as an antecedent stimulus on study behavior and concurrent completion and accuracy of reading and writing assignments were investigated for an 8-year-old first grade repeater who lacked motivation. Following baseline observations during which the teacher recorded study behavior and collected assignments with no…

  10. Indicators of Accuracy of Consumer Health Information on the Internet

    PubMed Central

    Fallis, Don; Frické, Martin

    2002-01-01

    Objectives: To identify indicators of accuracy for consumer health information on the Internet. The results will help lay people distinguish accurate from inaccurate health information on the Internet. Design: Several popular search engines (Yahoo, AltaVista, and Google) were used to find Web pages on the treatment of fever in children. The accuracy and completeness of these Web pages was determined by comparing their content with that of an instrument developed from authoritative sources on treating fever in children. The presence on these Web pages of a number of proposed indicators of accuracy, taken from published guidelines for evaluating the quality of health information on the Internet, was noted. Main Outcome Measures: Correlation between the accuracy of Web pages on treating fever in children and the presence of proposed indicators of accuracy on these pages. Likelihood ratios for the presence (and absence) of these proposed indicators. Results: One hundred Web pages were identified and characterized as “more accurate” or “less accurate.” Three indicators correlated with accuracy: displaying the HONcode logo, having an organization domain, and displaying a copyright. Many proposed indicators taken from published guidelines did not correlate with accuracy (e.g., the author being identified and the author having medical credentials) or inaccuracy (e.g., lack of currency and advertising). Conclusions: This method provides a systematic way of identifying indicators that are correlated with the accuracy (or inaccuracy) of health information on the Internet. Three such indicators have been identified in this study. Identifying such indicators and informing the providers and consumers of health information about them would be valuable for public health care. PMID:11751805

  11. Accuracy Of LTPP Traffic Loading Estimates

    DOT National Transportation Integrated Search

    1998-07-01

    The accuracy and reliability of traffic load estimates are key to determining a pavement's life expectancy. To better understand the variability of traffic loading rates and its effect on the accuracy of the Long Term Pavement Performance (LTPP) prog...

  12. Accuracy of velocities from repeated GPS surveys: relative positioning is concerned

    NASA Astrophysics Data System (ADS)

    Duman, Huseyin; Ugur Sanli, D.

    2016-04-01

    Over more than a decade, researchers have been interested in studying the accuracy of GPS positioning solutions. Recently, reporting the accuracy of GPS velocities has been added to this. Researchers studying landslide motion, tectonic motion, uplift, sea level rise, and subsidence still report results from GPS experiments in which repeated GPS measurements from short sessions are used. This motivated some other researchers to study the accuracy of GPS deformation rates/velocities from various repeated GPS surveys. In one of the efforts, the velocity accuracy was derived from repeated GPS static surveys using short observation sessions and Precise Point Positioning mode of GPS software. Velocities from short GPS sessions were compared with the velocities from 24 h sessions. The accuracy of velocities was obtained using statistical hypothesis testing and quantifying the accuracy of least squares estimation models. The results reveal that 45-60 % of the horizontal and none of the vertical solutions comply with the results from 24 h solutions. We argue that this case in which the data was evaluated using PPP should also apply to the case in which the data belonging to long GPS base lengths is processed using fundamental relative point positioning. To test this idea we chose the two IGS stations ANKR and NICO and derive their velocities from the reference stations held fixed in the stable EURASIAN plate. The University of Bern's GNSS software BERNESE was used to produce relative positioning solutions, and the results are compared with those of GIPSY/OASIS II PPP results. First impressions indicate that it is worth designing a global experiment and test these ideas in detail.

  13. Accuracy of lung nodule volumetry in low-dose CT with iterative reconstruction: an anthropomorphic thoracic phantom study.

    PubMed

    Doo, K W; Kang, E-Y; Yong, H S; Woo, O H; Lee, K Y; Oh, Y-W

    2014-09-01

    The purpose of this study was to assess accuracy of lung nodule volumetry in low-dose CT with application of iterative reconstruction (IR) according to nodule size, nodule density and CT tube currents, using artificial lung nodules within an anthropomorphic thoracic phantom. Eight artificial nodules (four diameters: 5, 8, 10 and 12 mm; two CT densities: -630 HU that represents ground-glass nodule and +100 HU that represents solid nodule) were randomly placed inside a thoracic phantom. Scans were performed with tube current-time product to 10, 20, 30 and 50 mAs. Images were reconstructed with IR and filtered back projection (FBP). We compared volume estimates to a reference standard and calculated the absolute percentage error (APE). The APE of all nodules was significantly lower when IR was used than with FBP (7.5 ± 4.7% compared with 9.0 ±6.9%; p < 0.001). The effect of IR was more pronounced for smaller nodules (p < 0.001). IR showed a significantly lower APE than FBP in ground-glass nodules (p < 0.0001), and the difference was more pronounced at the lowest tube current (11.8 ± 5.9% compared with 21.3 ± 6.1%; p < 0.0001). The effect of IR was most pronounced for ground-glass nodules in the lowest CT tube current. Lung nodule volumetry in low-dose CT by application of IR showed reliable accuracy in a phantom study. Lung nodule volumetry can be reliably applicable to all lung nodules including small, ground-glass nodules even in ultra-low-dose CT with application of IR. IR significantly improved the accuracy of lung nodule volumetry compared with FBP particularly for ground-glass (-630 HU) nodules. Volumetry in low-dose CT can be utilized in patient with lung nodule work-up, and IR has benefit for small, ground-glass lung nodules in low-dose CT.

  14. Constructing better classifier ensemble based on weighted accuracy and diversity measure.

    PubMed

    Zeng, Xiaodong; Wong, Derek F; Chao, Lidia S

    2014-01-01

    A weighted accuracy and diversity (WAD) method is presented, a novel measure used to evaluate the quality of the classifier ensemble, assisting in the ensemble selection task. The proposed measure is motivated by a commonly accepted hypothesis; that is, a robust classifier ensemble should not only be accurate but also different from every other member. In fact, accuracy and diversity are mutual restraint factors; that is, an ensemble with high accuracy may have low diversity, and an overly diverse ensemble may negatively affect accuracy. This study proposes a method to find the balance between accuracy and diversity that enhances the predictive ability of an ensemble for unknown data. The quality assessment for an ensemble is performed such that the final score is achieved by computing the harmonic mean of accuracy and diversity, where two weight parameters are used to balance them. The measure is compared to two representative measures, Kappa-Error and GenDiv, and two threshold measures that consider only accuracy or diversity, with two heuristic search algorithms, genetic algorithm, and forward hill-climbing algorithm, in ensemble selection tasks performed on 15 UCI benchmark datasets. The empirical results demonstrate that the WAD measure is superior to others in most cases.

  15. Constructing Better Classifier Ensemble Based on Weighted Accuracy and Diversity Measure

    PubMed Central

    Chao, Lidia S.

    2014-01-01

    A weighted accuracy and diversity (WAD) method is presented, a novel measure used to evaluate the quality of the classifier ensemble, assisting in the ensemble selection task. The proposed measure is motivated by a commonly accepted hypothesis; that is, a robust classifier ensemble should not only be accurate but also different from every other member. In fact, accuracy and diversity are mutual restraint factors; that is, an ensemble with high accuracy may have low diversity, and an overly diverse ensemble may negatively affect accuracy. This study proposes a method to find the balance between accuracy and diversity that enhances the predictive ability of an ensemble for unknown data. The quality assessment for an ensemble is performed such that the final score is achieved by computing the harmonic mean of accuracy and diversity, where two weight parameters are used to balance them. The measure is compared to two representative measures, Kappa-Error and GenDiv, and two threshold measures that consider only accuracy or diversity, with two heuristic search algorithms, genetic algorithm, and forward hill-climbing algorithm, in ensemble selection tasks performed on 15 UCI benchmark datasets. The empirical results demonstrate that the WAD measure is superior to others in most cases. PMID:24672402

  16. Communication Accuracy in Magazine Science Reporting.

    ERIC Educational Resources Information Center

    Borman, Susan Cray

    1978-01-01

    Evaluators with scientific expertise who analyzed the accuracy of popularized science news in mass circulation magazines found that the over-all accuracy of the magazine articles was good, and that the major problem was the omission of relevant information. (GW)

  17. Sampling strategies for improving tree accuracy and phylogenetic analyses: a case study in ciliate protists, with notes on the genus Paramecium.

    PubMed

    Yi, Zhenzhen; Strüder-Kypke, Michaela; Hu, Xiaozhong; Lin, Xiaofeng; Song, Weibo

    2014-02-01

    In order to assess how dataset-selection for multi-gene analyses affects the accuracy of inferred phylogenetic trees in ciliates, we chose five genes and the genus Paramecium, one of the most widely used model protist genera, and compared tree topologies of the single- and multi-gene analyses. Our empirical study shows that: (1) Using multiple genes improves phylogenetic accuracy, even when their one-gene topologies are in conflict with each other. (2) The impact of missing data on phylogenetic accuracy is ambiguous: resolution power and topological similarity, but not number of represented taxa, are the most important criteria of a dataset for inclusion in concatenated analyses. (3) As an example, we tested the three classification models of the genus Paramecium with a multi-gene based approach, and only the monophyly of the subgenus Paramecium is supported. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Emergency Department Length of Stay: Accuracy of Patient Estimates

    PubMed Central

    Parker, Brendan T.; Marco, Catherine

    2014-01-01

    Introduction Managing a patient’s expectations in the emergency department (ED) environment is challenging. Previous studies have identified several factors associated with ED patient satisfaction. Lengthy wait times have shown to be associated with dissatisfaction with ED care. Understanding that patients are inaccurate at their estimation of wait time, which could lead to lower satisfaction, provides administrators possible points of intervention to help improve accuracy of estimation and possibly satisfaction with the ED. This study was undertaken to examine the accuracy of patient estimates of time periods in an ED and identify factors associated with accuracy. Method In this prospective convenience sample survey at UTMC ED, we collected data between March and July 2012. Outcome measures included duration of each phase of ED care and patient estimates of these time periods. Results Among 309 participants, the majority underestimated the total length of stay (LOS) in the ED (median difference −7 minutes (IQR −29-12)). There was significant variability in ED LOS (median 155 minutes (IQR 75–240)). No significant associations were identified between accuracy of time estimates and gender, age, race, or insurance status. Participants with longer ED LOS demonstrated lower patient satisfaction scores (p<0.001). Conclusion Patients demonstrated inaccurate time estimates of ED treatment times, including total LOS. Patients with longer ED LOS had lower patient satisfaction scores. PMID:24672606

  19. Climate Change Accuracy: Requirements and Economic Value

    NASA Astrophysics Data System (ADS)

    Wielicki, B. A.; Cooke, R.; Mlynczak, M. G.; Lukashin, C.; Thome, K. J.; Baize, R. R.

    2014-12-01

    Higher than normal accuracy is required to rigorously observe decadal climate change. But what level is needed? How can this be quantified? This presentation will summarize a new more rigorous and quantitative approach to determining the required accuracy for climate change observations (Wielicki et al., 2013, BAMS). Most current global satellite observations cannot meet this accuracy level. A proposed new satellite mission to resolve this challenge is CLARREO (Climate Absolute Radiance and Refractivity Observatory). CLARREO is designed to achieve advances of a factor of 10 for reflected solar spectra and a factor of 3 to 5 for thermal infrared spectra (Wielicki et al., Oct. 2013 BAMS). The CLARREO spectrometers are designed to serve as SI traceable benchmarks for the Global Satellite Intercalibration System (GSICS) and to greatly improve the utility of a wide range of LEO and GEO infrared and reflected solar passive satellite sensors for climate change observations (e.g. CERES, MODIS, VIIIRS, CrIS, IASI, Landsat, SPOT, etc). Providing more accurate decadal change trends can in turn lead to more rapid narrowing of key climate science uncertainties such as cloud feedback and climate sensitivity. A study has been carried out to quantify the economic benefits of such an advance as part of a rigorous and complete climate observing system. The study concludes that the economic value is $12 Trillion U.S. dollars in Net Present Value for a nominal discount rate of 3% (Cooke et al. 2013, J. Env. Sys. Dec.). A brief summary of these two studies and their implications for the future of climate science will be presented.

  20. Evaluating Rater Accuracy in Rater-Mediated Assessments Using an Unfolding Model

    ERIC Educational Resources Information Center

    Wang, Jue; Engelhard, George, Jr.; Wolfe, Edward W.

    2016-01-01

    The number of performance assessments continues to increase around the world, and it is important to explore new methods for evaluating the quality of ratings obtained from raters. This study describes an unfolding model for examining rater accuracy. Accuracy is defined as the difference between observed and expert ratings. Dichotomous accuracy…

  1. Accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints.

    PubMed

    Siegenthaler, Andreas; Mlekusch, Sabine; Trelle, Sven; Schliessbach, Juerg; Curatolo, Michele; Eichenberger, Urs

    2012-08-01

    Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control. Sixty volunteers were studied. Ultrasound-imaging was used to place the needle to the bony target of cervical zygapophysial joint nerve blocks. The levels of needle placement were determined randomly (three levels per volunteer). After ultrasound-guided needle placement and application of 0.2 ml contrast dye, fluoroscopic imaging was performed for later evaluation by a blinded pain physician and considered as gold standard. Raw agreement, chance-corrected agreement κ, and chance-independent agreement Φ between the ultrasound-guided placement and the assessment using fluoroscopy were calculated to quantify accuracy. One hundred eighty needles were placed in 60 volunteers. Raw agreement was 87% (95% CI 81-91%), κ was 0.74 (0.64-0.83), and Φ 0.99 (0.99-0.99). Accuracy varied significantly between the different cervical nerves: it was low for the C7 medial branch, whereas all other levels showed very good accuracy. Ultrasound-imaging is an accurate technique for performing cervical zygapophysial joint nerve blocks in volunteers, except for the medial branch blocks of C7.

  2. Testing a tool for the classification of study designs in systematic reviews of interventions and exposures showed moderate reliability and low accuracy.

    PubMed

    Hartling, Lisa; Bond, Kenneth; Santaguida, P Lina; Viswanathan, Meera; Dryden, Donna M

    2011-08-01

    To develop and test a study design classification tool. We contacted relevant organizations and individuals to identify tools used to classify study designs and ranked these using predefined criteria. The highest ranked tool was a design algorithm developed, but no longer advocated, by the Cochrane Non-Randomized Studies Methods Group; this was modified to include additional study designs and decision points. We developed a reference classification for 30 studies; 6 testers applied the tool to these studies. Interrater reliability (Fleiss' κ) and accuracy against the reference classification were assessed. The tool was further revised and retested. Initial reliability was fair among the testers (κ=0.26) and the reference standard raters κ=0.33). Testing after revisions showed improved reliability (κ=0.45, moderate agreement) with improved, but still low, accuracy. The most common disagreements were whether the study design was experimental (5 of 15 studies), and whether there was a comparison of any kind (4 of 15 studies). Agreement was higher among testers who had completed graduate level training versus those who had not. The moderate reliability and low accuracy may be because of lack of clarity and comprehensiveness of the tool, inadequate reporting of the studies, and variability in tester characteristics. The results may not be generalizable to all published studies, as the test studies were selected because they had posed challenges for previous reviewers with respect to their design classification. Application of such a tool should be accompanied by training, pilot testing, and context-specific decision rules. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Accuracy of tree diameter estimation from terrestrial laser scanning by circle-fitting methods

    NASA Astrophysics Data System (ADS)

    Koreň, Milan; Mokroš, Martin; Bucha, Tomáš

    2017-12-01

    This study compares the accuracies of diameter at breast height (DBH) estimations by three initial (minimum bounding box, centroid, and maximum distance) and two refining (Monte Carlo and optimal circle) circle-fitting methods The circle-fitting algorithms were evaluated in multi-scan mode and a simulated single-scan mode on 157 European beech trees (Fagus sylvatica L.). DBH measured by a calliper was used as reference data. Most of the studied circle-fitting algorithms significantly underestimated the mean DBH in both scanning modes. Only the Monte Carlo method in the single-scan mode significantly overestimated the mean DBH. The centroid method proved to be the least suitable and showed significantly different results from the other circle-fitting methods in both scanning modes. In multi-scan mode, the accuracy of the minimum bounding box method was not significantly different from the accuracies of the refining methods The accuracy of the maximum distance method was significantly different from the accuracies of the refining methods in both scanning modes. The accuracy of the Monte Carlo method was significantly different from the accuracy of the optimal circle method in only single-scan mode. The optimal circle method proved to be the most accurate circle-fitting method for DBH estimation from point clouds in both scanning modes.

  4. Meta-Analyses of Diagnostic Accuracy in Imaging Journals: Analysis of Pooling Techniques and Their Effect on Summary Estimates of Diagnostic Accuracy.

    PubMed

    McGrath, Trevor A; McInnes, Matthew D F; Korevaar, Daniël A; Bossuyt, Patrick M M

    2016-10-01

    Purpose To determine whether authors of systematic reviews of diagnostic accuracy studies published in imaging journals used recommended methods for meta-analysis, and to evaluate the effect of traditional methods on summary estimates of sensitivity and specificity. Materials and Methods Medline was searched for published systematic reviews that included meta-analysis of test accuracy data limited to imaging journals published from January 2005 to May 2015. Two reviewers independently extracted study data and classified methods for meta-analysis as traditional (univariate fixed- or random-effects pooling or summary receiver operating characteristic curve) or recommended (bivariate model or hierarchic summary receiver operating characteristic curve). Use of methods was analyzed for variation with time, geographical location, subspecialty, and journal. Results from reviews in which study authors used traditional univariate pooling methods were recalculated with a bivariate model. Results Three hundred reviews met the inclusion criteria, and in 118 (39%) of those, authors used recommended meta-analysis methods. No change in the method used was observed with time (r = 0.54, P = .09); however, there was geographic (χ(2) = 15.7, P = .001), subspecialty (χ(2) = 46.7, P < .001), and journal (χ(2) = 27.6, P < .001) heterogeneity. Fifty-one univariate random-effects meta-analyses were reanalyzed with the bivariate model; the average change in the summary estimate was -1.4% (P < .001) for sensitivity and -2.5% (P < .001) for specificity. The average change in width of the confidence interval was 7.7% (P < .001) for sensitivity and 9.9% (P ≤ .001) for specificity. Conclusion Recommended methods for meta-analysis of diagnostic accuracy in imaging journals are used in a minority of reviews; this has not changed significantly with time. Traditional (univariate) methods allow overestimation of diagnostic accuracy and provide narrower confidence intervals than do recommended

  5. Clinically inappropriate post hoc exclusion of study participants from test accuracy calculations: the ROMA score, an example from a recent NICE diagnostic assessment.

    PubMed

    Lang, Shona; Armstrong, Nigel; Deshpande, Sohan; Ramaekers, Bram; Grimm, Sabine; de Kock, Shelley; Kleijnen, Jos; Westwood, Marie

    2018-01-01

    Objective To explore how the definition of the target condition and post hoc exclusion of participants can limit the usefulness of diagnostic accuracy studies. Methods We used data from a systematic review, conducted for a NICE diagnostic assessment of risk scores to inform secondary care decisions about specialist referral for women with suspected ovarian cancer, to explore how the definition of the target condition and post hoc exclusion of participants can limit the usefulness of diagnostic accuracy studies to inform clinical practice. Results Fourteen of the studies evaluated the ROMA score, nine used Abbott ARCHITECT tumour marker assays, five used Roche Elecsys. The summary sensitivity estimate (Abbott ARCHITECT) was highest, 95.1% (95% CI: 92.4 to 97.1%), where analyses excluded participants with borderline tumours or malignancies other than epithelial ovarian cancer and lowest, 75.0% (95% CI: 60.4 to 86.4%), where all participants were included. Results were similar for Roche Elecsys tumour marker assays. Although the number of patients involved was small, data from studies that reported diagnostic accuracy for both the whole study population and with post hoc exclusion of those with borderline or non-epithelial malignancies suggested that patients with borderline or malignancies other than epithelial ovarian cancer accounts for between 50 and 85% of false-negative ROMA scores. Conclusions Our results illustrate the potential consequences of inappropriate population selection in diagnostic studies; women with non-epithelial ovarian cancers or non-ovarian primaries, and those borderline tumours may be disproportionately represented among those with false negative, 'low risk' ROMA scores. These observations highlight the importance of giving careful consideration to how the target condition has been defined when assessing whether the diagnostic accuracy estimates reported in clinical studies will translate into clinical utility in real-world settings.

  6. Diagnosis of tuberculosis pleurisy with adenosine deaminase (ADA): a systematic review and meta-analysis.

    PubMed

    Gui, Xuwei; Xiao, Heping

    2014-01-01

    This systematic review and meta-analysis was performed to determine accuracy and usefulness of adenosine deaminase (ADA) in diagnosis of tuberculosis pleurisy. Medline, Google scholar and Web of Science databases were searched to identify related studies until 2014. Two reviewers independently assessed quality of studies included according to standard Quality Assessment of Diagnosis Accuracy Studies (QUADAS) criteria. The sensitivity, specificity, diagnostic odds ratio and other parameters of ADA in diagnosis of tuberculosis pleurisy were analyzed with Meta-DiSC1.4 software, and pooled using the random effects model. Twelve studies including 865 tuberculosis pleurisy patients and 1379 non-tuberculosis pleurisy subjects were identified from 110 studies for this meta-analysis. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR) and diagnosis odds ratio (DOR) of ADA in the diagnosis of tuberculosis pleurisy were 45.25 (95% CI 27.63-74.08), 0.86 (95% CI 0.84-0.88), 0.88 (95% CI 0.86-0.90), 6.32 (95% CI 4.83-8.26) and 0.15 (95% 0.11-0.22), respectively. The area under the summary receiver operating characteristic curve (SROC) was 0.9340. Our results demonstrate that the sensitivity and specificity of ADA are high in the diagnosis of tuberculosis pleurisy especially when ADA≥50 (U/L). Thus, ADA is a relatively sensitive and specific marker for tuberculosis pleurisy diagnosis. However, it is cautious to apply these results due to the heterogeneity in study design of these studies. Further studies are required to confirm the optimal cut-off value of ADA.

  7. Precision and accuracy of luminescence lifetime-based phosphor thermometry: A case study of Eu(III):YSZ

    NASA Astrophysics Data System (ADS)

    Heeg, B.; Jenkins, T. P.

    2013-09-01

    Laser induced phosphor thermometry as a reliable technique requires an analysis of factors controlling or contributing to the precision and accuracy of a measurement. In this paper, we discuss several critical design parameters in the development of luminescence lifetime-based phosphor thermometry instrumentation for use at elevated temperatures such as encountered in hot sections of gas turbine engines. As precision is predominantly governed by signal and background photon shot noise and detector noise, a brief summary is presented of how these noise contributions may affect the measurement. Accuracy, on the other hand, is governed by a range of effects including, but not limited to, detector response characteristics, laser-induced effects, the photo-physics of the sensor materials, and also the method of data reduction. The various possible outcomes of measurement precision and accuracy are discussed with luminescence lifetime measurements on Eu(III):YSZ sensor coatings.

  8. Accuracy of Point-of-care Ultrasonography for Diagnosing Acute Appendicitis: A Systematic Review and Meta-analysis.

    PubMed

    Matthew Fields, J; Davis, Joshua; Alsup, Carl; Bates, Amanda; Au, Arthur; Adhikari, Srikar; Farrell, Isaac

    2017-09-01

    The use of ultrasonography (US) to diagnose appendicitis is well established. More recently, point-of-care ultrasonography (POCUS) has also been studied for the diagnosis of appendicitis, which may also prove a valuable diagnostic tool. The purpose of this study was through systematic review and meta-analysis to identify the test characteristics of POCUS, specifically US performed by a nonradiologist physician, in accurately diagnosing acute appendicitis in patients of any age. We conducted a thorough and systematic literature search of English language articles published on point-of-care, physician-performed transabdominal US used for the diagnosis of acute appendicitis from 1980 to May, 2015 using OVID MEDLINE In-Process & Other Non-indexed Citations and Scopus. Studies were selected and subsequently independently abstracted by two trained reviewers. A random-effects pooled analysis was used to construct a hierarchical summary receiver operator characteristic curve, and a meta-regression was performed. Quality of studies was assessed using the QUADAS-2 tool. Our search yielded 5,792 unique studies and we included 21 of these in our final review. Prevalence of disease in this study was 29.8%, (range = 6.4%-75.4%). The sensitivity and specificity for POCUS in diagnosing appendicitis were 91% (95% confidence interval [CI] = 83%-96%) and 97% (95% CI = 91%-99%), respectively. The positive and negative predictive values were 91 and 94%, respectively. Studies performed by emergency physicians had slightly lower test characteristics (sensitivity = 80%, specificity = 92%). There was significant heterogeneity between studies (I 2 = 99%, 95% CI = 99%-100%) and the quality of the reported studies was moderate, mostly due to unclear reporting of blinding of physicians and timing of scanning and patient enrollment. Several of the studies were performed by a single operator, and the education and training of the operators were variably reported. Point-of-care US has relatively

  9. It Matters Whether Reading Comprehension Is Conceptualised as Rate or Accuracy

    ERIC Educational Resources Information Center

    Rønberg, Louise Flensted; Petersen, Dorthe Klint

    2016-01-01

    This study shows that it makes a difference whether accuracy measures or rate measures are used when assessing reading comprehension. When the outcome is reading comprehension accuracy (i.e., the number of correct responses), word reading skills (measured as access to orthographic representations) account for a modest amount of the variance in the…

  10. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data

    PubMed Central

    Coomans, Frederik; Hofman, Abe; Brinkhuis, Matthieu; van der Maas, Han L. J.; Maris, Gunter

    2016-01-01

    We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two ‘one-process’ models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a ‘two-process’ model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses. PMID:27167518

  11. Distinguishing Fast and Slow Processes in Accuracy - Response Time Data.

    PubMed

    Coomans, Frederik; Hofman, Abe; Brinkhuis, Matthieu; van der Maas, Han L J; Maris, Gunter

    2016-01-01

    We investigate the relation between speed and accuracy within problem solving in its simplest non-trivial form. We consider tests with only two items and code the item responses in two binary variables: one indicating the response accuracy, and one indicating the response speed. Despite being a very basic setup, it enables us to study item pairs stemming from a broad range of domains such as basic arithmetic, first language learning, intelligence-related problems, and chess, with large numbers of observations for every pair of problems under consideration. We carry out a survey over a large number of such item pairs and compare three types of psychometric accuracy-response time models present in the literature: two 'one-process' models, the first of which models accuracy and response time as conditionally independent and the second of which models accuracy and response time as conditionally dependent, and a 'two-process' model which models accuracy contingent on response time. We find that the data clearly violates the restrictions imposed by both one-process models and requires additional complexity which is parsimoniously provided by the two-process model. We supplement our survey with an analysis of the erroneous responses for an example item pair and demonstrate that there are very significant differences between the types of errors in fast and slow responses.

  12. Fundamental Importance of Reference Glucose Analyzer Accuracy for Evaluating the Performance of Blood Glucose Monitoring Systems (BGMSs).

    PubMed

    Bailey, Timothy S; Klaff, Leslie J; Wallace, Jane F; Greene, Carmine; Pardo, Scott; Harrison, Bern; Simmons, David A

    2016-07-01

    As blood glucose monitoring system (BGMS) accuracy is based on comparison of BGMS and laboratory reference glucose analyzer results, reference instrument accuracy is important to discriminate small differences between BGMS and reference glucose analyzer results. Here, we demonstrate the important role of reference glucose analyzer accuracy in BGMS accuracy evaluations. Two clinical studies assessed the performance of a new BGMS, using different reference instrument procedures. BGMS and YSI analyzer results were compared for fingertip blood that was obtained by untrained subjects' self-testing and study staff testing, respectively. YSI analyzer accuracy was monitored using traceable serum controls. In study 1 (N = 136), 94.1% of BGMS results were within International Organization for Standardization (ISO) 15197:2013 accuracy criteria; YSI analyzer serum control results showed a negative bias (-0.64% to -2.48%) at the first site and a positive bias (3.36% to 6.91%) at the other site. In study 2 (N = 329), 97.8% of BGMS results were within accuracy criteria; serum controls showed minimal bias (<0.92%) at both sites. These findings suggest that the ability to demonstrate that a BGMS meets accuracy guidelines is influenced by reference instrument accuracy. © 2016 Diabetes Technology Society.

  13. The effect of morphology on spelling and reading accuracy: a study on Italian children

    PubMed Central

    Angelelli, Paola; Marinelli, Chiara Valeria; Burani, Cristina

    2014-01-01

    In opaque orthographies knowledge of morphological information helps in achieving reading and spelling accuracy. In transparent orthographies with regular print-to-sound correspondences, such as Italian, the mappings of orthography onto phonology and phonology onto orthography are in principle sufficient to read and spell most words. The present study aimed to investigate the role of morphology in the reading and spelling accuracy of Italian children as a function of school experience to determine whether morphological facilitation was present in children learning a transparent orthography. The reading and spelling performances of 15 third-grade and 15 fifth-grade typically developing children were analyzed. Children read aloud and spelled both low-frequency words and pseudowords. Low-frequency words were manipulated for the presence of morphological structure (morphemic words vs. non-derived words). Morphemic words could also vary for the frequency (high vs. low) of roots and suffixes. Pseudo-words were made up of either a real root and a real derivational suffix in a combination that does not exist in the Italian language or had no morphological constituents. Results showed that, in Italian, morphological information is a useful resource for both reading and spelling. Typically developing children benefitted from the presence of morphological structure when they read and spelled pseudowords; however, in processing low-frequency words, morphology facilitated reading but not spelling. These findings are discussed in terms of morpho-lexical access and successful cooperation between lexical and sublexical processes in reading and spelling. PMID:25477855

  14. The effect of morphology on spelling and reading accuracy: a study on Italian children.

    PubMed

    Angelelli, Paola; Marinelli, Chiara Valeria; Burani, Cristina

    2014-01-01

    In opaque orthographies knowledge of morphological information helps in achieving reading and spelling accuracy. In transparent orthographies with regular print-to-sound correspondences, such as Italian, the mappings of orthography onto phonology and phonology onto orthography are in principle sufficient to read and spell most words. The present study aimed to investigate the role of morphology in the reading and spelling accuracy of Italian children as a function of school experience to determine whether morphological facilitation was present in children learning a transparent orthography. The reading and spelling performances of 15 third-grade and 15 fifth-grade typically developing children were analyzed. Children read aloud and spelled both low-frequency words and pseudowords. Low-frequency words were manipulated for the presence of morphological structure (morphemic words vs. non-derived words). Morphemic words could also vary for the frequency (high vs. low) of roots and suffixes. Pseudo-words were made up of either a real root and a real derivational suffix in a combination that does not exist in the Italian language or had no morphological constituents. Results showed that, in Italian, morphological information is a useful resource for both reading and spelling. Typically developing children benefitted from the presence of morphological structure when they read and spelled pseudowords; however, in processing low-frequency words, morphology facilitated reading but not spelling. These findings are discussed in terms of morpho-lexical access and successful cooperation between lexical and sublexical processes in reading and spelling.

  15. Cued Speech Transliteration: Effects of Speaking Rate and Lag Time on Production Accuracy

    PubMed Central

    Tessler, Morgan P.

    2016-01-01

    Many deaf and hard-of-hearing children rely on interpreters to access classroom communication. Although the exact level of access provided by interpreters in these settings is unknown, it is likely to depend heavily on interpreter accuracy (portion of message correctly produced by the interpreter) and the factors that govern interpreter accuracy. In this study, the accuracy of 12 Cued Speech (CS) transliterators with varying degrees of experience was examined at three different speaking rates (slow, normal, fast). Accuracy was measured with a high-resolution, objective metric in order to facilitate quantitative analyses of the effect of each factor on accuracy. Results showed that speaking rate had a large negative effect on accuracy, caused primarily by an increase in omitted cues, whereas the effect of lag time on accuracy, also negative, was quite small and explained just 3% of the variance. Increased experience level was generally associated with increased accuracy; however, high levels of experience did not guarantee high levels of accuracy. Finally, the overall accuracy of the 12 transliterators, 54% on average across all three factors, was low enough to raise serious concerns about the quality of CS transliteration services that (at least some) children receive in educational settings. PMID:27221370

  16. Diagnostic evaluation of sentinel lymph node biopsy using indocyanine green and infrared or fluorescent imaging in gastric cancer: a systematic review and meta-analysis.

    PubMed

    Skubleny, Daniel; Dang, Jerry T; Skulsky, Samuel; Switzer, Noah; Tian, Chunhong; Shi, Xinzhe; de Gara, Christopher; Birch, Daniel W; Karmali, Shahzeer

    2018-06-01

    Sentinel node navigation surgery (SNNS) for gastric cancer using infrared visualization of indocyanine green (ICG) is intriguing because it may limit operative morbidity. We are the first to systematically review and perform meta-analysis on the diagnostic utility of ICG and infrared electronic endoscopy (IREE) or near infrared fluorescent imaging (NIFI) for SNNS exclusively in gastric cancer. A search of electronic databases MEDLINE, EMBASE, SCOPUS, Web of Science, and the Cochrane Library using search terms "gastric/stomach" AND "tumor/carcinoma/cancer/neoplasm/adenocarcinoma/malignancy" AND "indocyanine green" was completed in May 2017. Articles were selected by two independent reviewers based on the following major inclusion criteria: (1) diagnostic accuracy study design; (2) indocyanine green was injected at tumor site; (3) IREE or NIFI was used for intraoperative visualization. 327 titles or abstracts were screened. The quality of included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2. Ten full text studies were selected. 643 patients were identified with the majority of patients possessing T1 tumors (79.8%). Pooled identification rate, diagnostic odds ratio, sensitivity, and specificity were 0.99 (0.97-1.0), 380.0 (68.71-2101), 0.87 (0.80-0.93), and 1.00 (0.99-1.00), respectively. The summary receiver operator characteristic for ICG + IREE/NIFI demonstrated a test accuracy of 98.3%. Subgroup analysis found improved test performance for studies with low-risk QUADAS-2 scores, studies published after 2010 and submucosal ICG injection. IREE had improved diagnostic odds ratio, sensitivity, and identification rate compared to NIFI. Heterogeneity among studies ranged from low (I 2  < 25%) to high (I 2  > 75%). We found encouraging results regarding the accuracy, diagnostic odds ratio, and specificity of the test. The sensitivity was not optimal but may be improved by a strict protocol to augment the technique. Given

  17. Diagnostic value of 18F-FDG-PET/CT for the evaluation of solitary pulmonary nodules: a systematic review and meta-analysis.

    PubMed

    Ruilong, Zong; Daohai, Xie; Li, Geng; Xiaohong, Wang; Chunjie, Wang; Lei, Tian

    2017-01-01

    To carry out a meta-analysis on the performance of fluorine-18-fluorodeoxyglucose (F-FDG) PET/computed tomography (PET/CT) for the evaluation of solitary pulmonary nodules. In the meta-analysis, we performed searches of several electronic databases for relevant studies, including Google Scholar, PubMed, Cochrane Library, and several Chinese databases. The quality of all included studies was assessed by Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2). Two observers independently extracted data of eligible articles. For the meta-analysis, the total sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratios were pooled. A summary receiver operating characteristic curve was constructed. The I-test was performed to assess the impact of study heterogeneity on the results of the meta-analysis. Meta-regression and subgroup analysis were carried out to investigate the potential covariates that might have considerable impacts on heterogeneity. Overall, 12 studies were included in this meta-analysis, including a total of 1297 patients and 1301 pulmonary nodules. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio with corresponding 95% confidence intervals (CIs) were 0.82 (95% CI, 0.76-0.87), 0.81 (95% CI, 0.66-0.90), 4.3 (95% CI, 2.3-7.9), and 0.22 (95% CI, 0.16-0.30), respectively. Significant heterogeneity was observed in sensitivity (I=81.1%) and specificity (I=89.6%). Subgroup analysis showed that the best results for sensitivity (0.90; 95% CI, 0.68-0.86) and accuracy (0.93; 95% CI, 0.90-0.95) were present in a prospective study. The results of our analysis suggest that PET/CT is a useful tool for detecting malignant pulmonary nodules qualitatively. Although current evidence showed moderate accuracy for PET/CT in differentiating malignant from benign solitary pulmonary nodules, further work needs to be carried out to improve its reliability.

  18. Thematic Accuracy Assessment of the 2011 National Land ...

    EPA Pesticide Factsheets

    Accuracy assessment is a standard protocol of National Land Cover Database (NLCD) mapping. Here we report agreement statistics between map and reference labels for NLCD 2011, which includes land cover for ca. 2001, ca. 2006, and ca. 2011. The two main objectives were assessment of agreement between map and reference labels for the three, single-date NLCD land cover products at Level II and Level I of the classification hierarchy, and agreement for 17 land cover change reporting themes based on Level I classes (e.g., forest loss; forest gain; forest, no change) for three change periods (2001–2006, 2006–2011, and 2001–2011). The single-date overall accuracies were 82%, 83%, and 83% at Level II and 88%, 89%, and 89% at Level I for 2011, 2006, and 2001, respectively. Many class-specific user's accuracies met or exceeded a previously established nominal accuracy benchmark of 85%. Overall accuracies for 2006 and 2001 land cover components of NLCD 2011 were approximately 4% higher (at Level II and Level I) than the overall accuracies for the same components of NLCD 2006. The high Level I overall, user's, and producer's accuracies for the single-date eras in NLCD 2011 did not translate into high class-specific user's and producer's accuracies for many of the 17 change reporting themes. User's accuracies were high for the no change reporting themes, commonly exceeding 85%, but were typically much lower for the reporting themes that represented change. Only forest l

  19. Developing a Weighted Measure of Speech Sound Accuracy

    PubMed Central

    Preston, Jonathan L.; Ramsdell, Heather L.; Oller, D. Kimbrough; Edwards, Mary Louise; Tobin, Stephen J.

    2010-01-01

    Purpose The purpose is to develop a system for numerically quantifying a speaker’s phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, we describe a system for differentially weighting speech sound errors based on various levels of phonetic accuracy with a Weighted Speech Sound Accuracy (WSSA) score. We then evaluate the reliability and validity of this measure. Method Phonetic transcriptions are analyzed from several samples of child speech, including preschoolers and young adolescents with and without speech sound disorders and typically developing toddlers. The new measure of phonetic accuracy is compared to existing measures, is used to discriminate typical and disordered speech production, and is evaluated to determine whether it is sensitive to changes in phonetic accuracy over time. Results Initial psychometric data indicate that WSSA scores correlate with other measures of phonetic accuracy as well as listeners’ judgments of severity of a child’s speech disorder. The measure separates children with and without speech sound disorders. WSSA scores also capture growth in phonetic accuracy in toddler’s speech over time. Conclusion Results provide preliminary support for the WSSA as a valid and reliable measure of phonetic accuracy in children’s speech. PMID:20699344

  20. High accuracy in short ISS missions

    NASA Astrophysics Data System (ADS)

    Rüeger, J. M.

    1986-06-01

    Traditionally Inertial Surveying Systems ( ISS) are used for missions of 30 km to 100 km length. Today, a new type of ISS application is emanating from an increased need for survey control densification in urban areas often in connection with land information systems or cadastral surveys. The accuracy requirements of urban surveys are usually high. The loss in accuracy caused by the coordinate transfer between IMU and ground marks is investigated and an offsetting system based on electronic tacheometers is proposed. An offsetting system based on a Hewlett-Packard HP 3820A electronic tacheometer has been tested in Sydney (Australia) in connection with a vehicle mounted LITTON Auto-Surveyor System II. On missions over 750 m ( 8 stations, 25 minutes duration, 3.5 minute ZUPT intervals, mean offset distances 9 metres) accuracies of 37 mm (one sigma) in position and 8 mm in elevation were achieved. Some improvements to the LITTON Auto-Surveyor System II are suggested which would improve the accuracies even further.

  1. Imaging in syndesmotic injury: a systematic literature review.

    PubMed

    Krähenbühl, Nicola; Weinberg, Maxwell W; Davidson, Nathan P; Mills, Megan K; Hintermann, Beat; Saltzman, Charles L; Barg, Alexej

    2018-05-01

    To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis. A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality. The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice. Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

  2. Free Mesh Method: fundamental conception, algorithms and accuracy study

    PubMed Central

    YAGAWA, Genki

    2011-01-01

    The finite element method (FEM) has been commonly employed in a variety of fields as a computer simulation method to solve such problems as solid, fluid, electro-magnetic phenomena and so on. However, creation of a quality mesh for the problem domain is a prerequisite when using FEM, which becomes a major part of the cost of a simulation. It is natural that the concept of meshless method has evolved. The free mesh method (FMM) is among the typical meshless methods intended for particle-like finite element analysis of problems that are difficult to handle using global mesh generation, especially on parallel processors. FMM is an efficient node-based finite element method that employs a local mesh generation technique and a node-by-node algorithm for the finite element calculations. In this paper, FMM and its variation are reviewed focusing on their fundamental conception, algorithms and accuracy. PMID:21558752

  3. Accuracy of body weight perception and obesity among Chinese Americans

    PubMed Central

    Liu, Shan; Hu, Sophia H.; Wang, Vincent Y.; Crupi, Robert; Qiu, Jeanna M.; Cleland, Chuck; Melkus, Gail D’Eramo

    2015-01-01

    Background Accuracy of body weight perception is an individual’s perception of their body weight in comparison with actual body weight and is associated with weight related behaviors. Chinese Americans have increased risk for obesity but no studies have examined accuracy of body weight perception. Methods This study was a descriptive and cross-sectional study, which was conducted in a community health center in New York. Study subjects were all Chinese-American adults. Demographic information, accuracy of perception of body weight, anthropometric measures (Weight, Height, BMI, weight to height ratio, weight to hip ratio), fasting plasma glucose (FPG), HbA1C and obesity related disease including hypertension, diabetes, heart disease, stroke were assessed. Results A total of 162 Chinese American were recruited.52 subjects (32%) did not perceive body weight correctly, in which 32 subjects had underestimation and 20 subjects had overestimation of body weight. Significant differences were found among subjects in three groups of different accuracy of body weight perception in terms of gender (p=0.003), age (p=0.003), education years (p=0.047). WC (p<0.001), HC (p=<0.001), weight/height ratio (p=0.001), BMI (p<0.001). Subjects in consistent/accurate estimation group and underestimation group had similar obesity related-characteristics but different from subjects in overestimation group. Discussion and Conclusion The study identified around one third of Chinese American did not perceive their body weight correctly. Intervention studies for obesity management in Chinese American should address gender difference, target on older subjects, and focus on educating the normal values and significances of WC, HC and HbA1C among Chinese Americans. PMID:25937164

  4. Does Maternal Body Mass Index Have an Effect on the Accuracy of Ultrasound-Derived Estimated Birth Weight?: A Retrospective Study.

    PubMed

    Gonzalez, Maritza G; Reed, Kathryn L; Center, Katherine E; Hill, Meghan G

    2017-05-01

    The purpose of this study was to investigate the relationship between the maternal body mass index (BMI) and the accuracy of ultrasound-derived birth weight. A retrospective chart review was performed on women who had an ultrasound examination between 36 and 43 weeks' gestation and had complete delivery data available through electronic medical records. The ultrasound-derived fetal weight was adjusted by 30 g per day of gestation that elapsed between the ultrasound examination and delivery to arrive at the predicted birth weight. A total of 403 pregnant women met inclusion criteria. Age ranged from 13-44 years (mean ± SD, 28.38 ± 5.97 years). The mean BMI was 32.62 ± 8.59 kg/m 2 . Most of the women did not have diabetes (n = 300 [74.0%]). The sample was primarily white (n = 165 [40.9%]) and Hispanic (n = 147 [36.5%]). The predicted weight of neonates at delivery (3677.07 ± 540.51 g) was higher than the actual birth weight (3335.92 ± 585.46 g). Based on regression analyses, as the BMI increased, so did the predicted weight (P < .01) and weight at delivery (P < .01). The accuracy of the estimated ultrasound-derived birth weight was not predicted by the maternal BMI (P = .22). Maternal race and diabetes status were not associated with the accuracy of ultrasound in predicting birth weight. Both predicted and actual birth weight increased as the BMI increased. However, the BMI did not affect the accuracy of the estimated ultrasound-derived birth weight. Maternal race and diabetes status did not influence the accuracy of the ultrasound-derived predicted birth weight. © 2017 by the American Institute of Ultrasound in Medicine.

  5. A Monte Carlo Study of the Effect of Item Characteristic Curve Estimation on the Accuracy of Three Person-Fit Statistics

    ERIC Educational Resources Information Center

    St-Onge, Christina; Valois, Pierre; Abdous, Belkacem; Germain, Stephane

    2009-01-01

    To date, there have been no studies comparing parametric and nonparametric Item Characteristic Curve (ICC) estimation methods on the effectiveness of Person-Fit Statistics (PFS). The primary aim of this study was to determine if the use of ICCs estimated by nonparametric methods would increase the accuracy of item response theory-based PFS for…

  6. Evaluation of mechanical accuracy for couch‐based tracking system (CBTS)

    PubMed Central

    Lee, Suk; Chang, Kyung‐Hwan; Shim, Jand Bo; Cao, Yuanjie; Lee, Chang Ki; Cho, Sam Ju; Yang, Dae Sik; Park, Young Je; Yoon, Won Seob

    2012-01-01

    This study evaluated the mechanical accuracy of an in‐house–developed couch‐based tracking system (CBTS) according to respiration data. The overall delay time of the CBTS was calculated, and the accuracy, reproducibility, and loading effect of the CBTS were evaluated according to the sinusoidal waveform and various respiratory motion data of real patients with and without a volunteer weighing 75 kg. The root mean square (rms) error of the accuracy, the reproducibility, and the sagging measurements were calculated for the three axes (X, Y, and Z directions) of the CBTS. The overall delay time of the CBTS was 0.251 sec. The accuracy and reproducibility in the Z direction in real patient data were poor, as indicated by high rms errors. The results of the loading effect were within 1.0 mm in all directions. This novel CBTS has the potential for clinical application for tumor tracking in radiation therapy. PACS number: 87.55.ne PMID:23149775

  7. Empirical Accuracies of U.S. Space Surveillance Network Reentry Predictions

    NASA Technical Reports Server (NTRS)

    Johnson, Nicholas L.

    2008-01-01

    The U.S. Space Surveillance Network (SSN) issues formal satellite reentry predictions for objects which have the potential for generating debris which could pose a hazard to people or property on Earth. These prognostications, known as Tracking and Impact Prediction (TIP) messages, are nominally distributed at daily intervals beginning four days prior to the anticipated reentry and several times during the final 24 hours in orbit. The accuracy of these messages depends on the nature of the satellite s orbit, the characteristics of the space vehicle, solar activity, and many other factors. Despite the many influences on the time and the location of reentry, a useful assessment of the accuracies of TIP messages can be derived and compared with the official accuracies included with each TIP message. This paper summarizes the results of a study of numerous uncontrolled reentries of spacecraft and rocket bodies from nearly circular orbits over a span of several years. Insights are provided into the empirical accuracies and utility of SSN TIP messages.

  8. Accuracy testing of steel and electric groundwater-level measuring tapes: Test method and in-service tape accuracy

    USGS Publications Warehouse

    Fulford, Janice M.; Clayton, Christopher S.

    2015-10-09

    The calibration device and proposed method were used to calibrate a sample of in-service USGS steel and electric groundwater tapes. The sample of in-service groundwater steel tapes were in relatively good condition. All steel tapes, except one, were accurate to ±0.01 ft per 100 ft over their entire length. One steel tape, which had obvious damage in the first hundred feet, was marginally outside the accuracy of ±0.01 ft per 100 ft by 0.001 ft. The sample of in-service groundwater-level electric tapes were in a range of conditions—from like new, with cosmetic damage, to nonfunctional. The in-service electric tapes did not meet the USGS accuracy recommendation of ±0.01 ft. In-service electric tapes, except for the nonfunctional tape, were accurate to about ±0.03 ft per 100 ft. A comparison of new with in-service electric tapes found that steel-core electric tapes maintained their length and accuracy better than electric tapes without a steel core. The in-service steel tapes could be used as is and achieve USGS accuracy recommendations for groundwater-level measurements. The in-service electric tapes require tape corrections to achieve USGS accuracy recommendations for groundwater-level measurement.

  9. The Accuracy of Shock Capturing in Two Spatial Dimensions

    NASA Technical Reports Server (NTRS)

    Carpenter, Mark H.; Casper, Jay H.

    1997-01-01

    An assessment of the accuracy of shock capturing schemes is made for two-dimensional steady flow around a cylindrical projectile. Both a linear fourth-order method and a nonlinear third-order method are used in this study. It is shown, contrary to conventional wisdom, that captured two-dimensional shocks are asymptotically first-order, regardless of the design accuracy of the numerical method. The practical implications of this finding are discussed in the context of the efficacy of high-order numerical methods for discontinuous flows.

  10. The methodological quality assessment tools for preclinical and clinical studies, systematic review and meta-analysis, and clinical practice guideline: a systematic review.

    PubMed

    Zeng, Xiantao; Zhang, Yonggang; Kwong, Joey S W; Zhang, Chao; Li, Sheng; Sun, Feng; Niu, Yuming; Du, Liang

    2015-02-01

    To systematically review the methodological assessment tools for pre-clinical and clinical studies, systematic review and meta-analysis, and clinical practice guideline. We searched PubMed, the Cochrane Handbook for Systematic Reviews of Interventions, Joanna Briggs Institute (JBI) Reviewers Manual, Centre for Reviews and Dissemination, Critical Appraisal Skills Programme (CASP), Scottish Intercollegiate Guidelines Network (SIGN), and the National Institute for Clinical Excellence (NICE) up to May 20th, 2014. Two authors selected studies and extracted data; quantitative analysis was performed to summarize the characteristics of included tools. We included a total of 21 assessment tools for analysis. A number of tools were developed by academic organizations, and some were developed by only a small group of researchers. The JBI developed the highest number of methodological assessment tools, with CASP coming second. Tools for assessing the methodological quality of randomized controlled studies were most abundant. The Cochrane Collaboration's tool for assessing risk of bias is the best available tool for assessing RCTs. For cohort and case-control studies, we recommend the use of the Newcastle-Ottawa Scale. The Methodological Index for Non-Randomized Studies (MINORS) is an excellent tool for assessing non-randomized interventional studies, and the Agency for Healthcare Research and Quality (ARHQ) methodology checklist is applicable for cross-sectional studies. For diagnostic accuracy test studies, the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool is recommended; the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) risk of bias tool is available for assessing animal studies; Assessment of Multiple Systematic Reviews (AMSTAR) is a measurement tool for systematic reviews/meta-analyses; an 18-item tool has been developed for appraising case series studies, and the Appraisal of Guidelines, Research and Evaluation (AGREE

  11. Cloud-based preoperative planning for total hip arthroplasty: a study of accuracy, efficiency, and compliance.

    PubMed

    Maratt, Joseph D; Srinivasan, Ramesh C; Dahl, William J; Schilling, Peter L; Urquhart, Andrew G

    2012-08-01

    As digital radiography becomes more prevalent, several systems for digital preoperative planning have become available. The purpose of this study was to evaluate the accuracy and efficiency of an inexpensive, cloud-based digital templating system, which is comparable with acetate templating. However, cloud-based templating is substantially faster and more convenient than acetate templating or locally installed software. Although this is a practical solution for this particular medical application, regulatory changes are necessary before the tremendous advantages of cloud-based storage and computing can be realized in medical research and clinical practice. Copyright 2012, SLACK Incorporated.

  12. A Comparative Study on Diagnostic Accuracy of Colour Coded Digital Images, Direct Digital Images and Conventional Radiographs for Periapical Lesions – An In Vitro Study

    PubMed Central

    Mubeen; K.R., Vijayalakshmi; Bhuyan, Sanat Kumar; Panigrahi, Rajat G; Priyadarshini, Smita R; Misra, Satyaranjan; Singh, Chandravir

    2014-01-01

    Objectives: The identification and radiographic interpretation of periapical bone lesions is important for accurate diagnosis and treatment. The present study was undertaken to study the feasibility and diagnostic accuracy of colour coded digital radiographs in terms of presence and size of lesion and to compare the diagnostic accuracy of colour coded digital images with direct digital images and conventional radiographs for assessing periapical lesions. Materials and Methods: Sixty human dry cadaver hemimandibles were obtained and periapical lesions were created in first and second premolar teeth at the junction of cancellous and cortical bone using a micromotor handpiece and carbide burs of sizes 2, 4 and 6. After each successive use of round burs, a conventional, RVG and colour coded image was taken for each specimen. All the images were evaluated by three observers. The diagnostic accuracy for each bur and image mode was calculated statistically. Results: Our results showed good interobserver (kappa > 0.61) agreement for the different radiographic techniques and for the different bur sizes. Conventional Radiography outperformed Digital Radiography in diagnosing periapical lesions made with Size two bur. Both were equally diagnostic for lesions made with larger bur sizes. Colour coding method was least accurate among all the techniques. Conclusion: Conventional radiography traditionally forms the backbone in the diagnosis, treatment planning and follow-up of periapical lesions. Direct digital imaging is an efficient technique, in diagnostic sense. Colour coding of digital radiography was feasible but less accurate however, this imaging technique, like any other, needs to be studied continuously with the emphasis on safety of patients and diagnostic quality of images. PMID:25584318

  13. Improving LUC estimation accuracy with multiple classification system for studying impact of urbanization on watershed flood

    NASA Astrophysics Data System (ADS)

    Dou, P.

    2017-12-01

    Guangzhou has experienced a rapid urbanization period called "small change in three years and big change in five years" since the reform of China, resulting in significant land use/cover changes(LUC). To overcome the disadvantages of single classifier for remote sensing image classification accuracy, a multiple classifier system (MCS) is proposed to improve the quality of remote sensing image classification. The new method combines advantages of different learning algorithms, and achieves higher accuracy (88.12%) than any single classifier did. With the proposed MCS, land use/cover (LUC) on Landsat images from 1987 to 2015 was obtained, and the LUCs were used on three watersheds (Shijing river, Chebei stream, and Shahe stream) to estimate the impact of urbanization on water flood. The results show that with the high accuracy LUC, the uncertainty in flood simulations are reduced effectively (for Shijing river, Chebei stream, and Shahe stream, the uncertainty reduced 15.5%, 17.3% and 19.8% respectively).

  14. Accuracy in Rietveld quantitative phase analysis: a comparative study of strictly monochromatic Mo and Cu radiations.

    PubMed

    León-Reina, L; García-Maté, M; Álvarez-Pinazo, G; Santacruz, I; Vallcorba, O; De la Torre, A G; Aranda, M A G

    2016-06-01

    This study reports 78 Rietveld quantitative phase analyses using Cu  K α 1 , Mo  K α 1 and synchrotron radiations. Synchrotron powder diffraction has been used to validate the most challenging analyses. From the results for three series with increasing contents of an analyte (an inorganic crystalline phase, an organic crystalline phase and a glass), it is inferred that Rietveld analyses from high-energy Mo  K α 1 radiation have slightly better accuracies than those obtained from Cu  K α 1 radiation. This behaviour has been established from the results of the calibration graphics obtained through the spiking method and also from Kullback-Leibler distance statistic studies. This outcome is explained, in spite of the lower diffraction power for Mo radiation when compared to Cu radiation, as arising because of the larger volume tested with Mo and also because higher energy allows one to record patterns with fewer systematic errors. The limit of detection (LoD) and limit of quantification (LoQ) have also been established for the studied series. For similar recording times, the LoDs in Cu patterns, ∼0.2 wt%, are slightly lower than those derived from Mo patterns, ∼0.3 wt%. The LoQ for a well crystallized inorganic phase using laboratory powder diffraction was established to be close to 0.10 wt% in stable fits with good precision. However, the accuracy of these analyses was poor with relative errors near to 100%. Only contents higher than 1.0 wt% yielded analyses with relative errors lower than 20%.

  15. Accuracy of stream habitat interpolations across spatial scales

    USGS Publications Warehouse

    Sheehan, Kenneth R.; Welsh, Stuart A.

    2013-01-01

    Stream habitat data are often collected across spatial scales because relationships among habitat, species occurrence, and management plans are linked at multiple spatial scales. Unfortunately, scale is often a factor limiting insight gained from spatial analysis of stream habitat data. Considerable cost is often expended to collect data at several spatial scales to provide accurate evaluation of spatial relationships in streams. To address utility of single scale set of stream habitat data used at varying scales, we examined the influence that data scaling had on accuracy of natural neighbor predictions of depth, flow, and benthic substrate. To achieve this goal, we measured two streams at gridded resolution of 0.33 × 0.33 meter cell size over a combined area of 934 m2 to create a baseline for natural neighbor interpolated maps at 12 incremental scales ranging from a raster cell size of 0.11 m2 to 16 m2 . Analysis of predictive maps showed a logarithmic linear decay pattern in RMSE values in interpolation accuracy for variables as resolution of data used to interpolate study areas became coarser. Proportional accuracy of interpolated models (r2 ) decreased, but it was maintained up to 78% as interpolation scale moved from 0.11 m2 to 16 m2 . Results indicated that accuracy retention was suitable for assessment and management purposes at various scales different from the data collection scale. Our study is relevant to spatial modeling, fish habitat assessment, and stream habitat management because it highlights the potential of using a single dataset to fulfill analysis needs rather than investing considerable cost to develop several scaled datasets.

  16. Accuracy of smartphone apps for heart rate measurement.

    PubMed

    Coppetti, Thomas; Brauchlin, Andreas; Müggler, Simon; Attinger-Toller, Adrian; Templin, Christian; Schönrath, Felix; Hellermann, Jens; Lüscher, Thomas F; Biaggi, Patric; Wyss, Christophe A

    2017-08-01

    Background Smartphone manufacturers offer mobile health monitoring technology to their customers, including apps using the built-in camera for heart rate assessment. This study aimed to test the diagnostic accuracy of such heart rate measuring apps in clinical practice. Methods The feasibility and accuracy of measuring heart rate was tested on four commercially available apps using both iPhone 4 and iPhone 5. 'Instant Heart Rate' (IHR) and 'Heart Fitness' (HF) work with contact photoplethysmography (contact of fingertip to built-in camera), while 'Whats My Heart Rate' (WMH) and 'Cardiio Version' (CAR) work with non-contact photoplethysmography. The measurements were compared to electrocardiogram and pulse oximetry-derived heart rate. Results Heart rate measurement using app-based photoplethysmography was performed on 108 randomly selected patients. The electrocardiogram-derived heart rate correlated well with pulse oximetry ( r = 0.92), IHR ( r = 0.83) and HF ( r = 0.96), but somewhat less with WMH ( r = 0.62) and CAR ( r = 0.60). The accuracy of app-measured heart rate as compared to electrocardiogram, reported as mean absolute error (in bpm ± standard error) was 2 ± 0.35 (pulse oximetry), 4.5 ± 1.1 (IHR), 2 ± 0.5 (HF), 7.1 ± 1.4 (WMH) and 8.1 ± 1.4 (CAR). Conclusions We found substantial performance differences between the four studied heart rate measuring apps. The two contact photoplethysmography-based apps had higher feasibility and better accuracy for heart rate measurement than the two non-contact photoplethysmography-based apps.

  17. A Clinical Comparative Study of 3-Dimensional Accuracy between Digital and Conventional Implant Impression Techniques.

    PubMed

    Alsharbaty, Mohammed Hussein M; Alikhasi, Marzieh; Zarrati, Simindokht; Shamshiri, Ahmed Reza

    2018-02-09

    To evaluate the accuracy of a digital implant impression technique using a TRIOS 3Shape intraoral scanner (IOS) compared to conventional implant impression techniques (pick-up and transfer) in clinical situations. Thirty-six patients who had two implants (Implantium, internal connection) ranging in diameter between 3.8 and 4.8 mm in posterior regions participated in this study after signing a consent form. Thirty-six reference models (RM) were fabricated by attaching two impression copings intraorally, splinted with autopolymerizing acrylic resin, verified by sectioning through the middle of the index, and rejoined again with freshly mixed autopolymerizing acrylic resin pattern (Pattern Resin) with the brush bead method. After that, the splinted assemblies were attached to implant analogs (DANSE) and impressed with type III dental stone (Gypsum Microstone) in standard plastic die lock trays. Thirty-six working casts were fabricated for each conventional impression technique (i.e., pick-up and transfer). Thirty-six digital impressions were made with a TRIOS 3Shape IOS. Eight of the digitally scanned files were damaged; 28 digital scan files were retrieved to STL format. A coordinate-measuring machine (CMM) was used to record linear displacement measurements (x, y, and z-coordinates), interimplant distances, and angular displacements for the RMs and conventionally fabricated working casts. CATIA 3D evaluation software was used to assess the digital STL files for the same variables as the CMM measurements. CMM measurements made on the RMs and conventionally fabricated working casts were compared with 3D software measurements made on the digitally scanned files. Data were statistically analyzed using the generalized estimating equation (GEE) with an exchangeable correlation matrix and linear method, followed by the Bonferroni method for pairwise comparisons (α = 0.05). The results showed significant differences between the pick-up and digital groups in all of the

  18. EEG channels reduction using PCA to increase XGBoost's accuracy for stroke detection

    NASA Astrophysics Data System (ADS)

    Fitriah, N.; Wijaya, S. K.; Fanany, M. I.; Badri, C.; Rezal, M.

    2017-07-01

    In Indonesia, based on the result of Basic Health Research 2013, the number of stroke patients had increased from 8.3 ‰ (2007) to 12.1 ‰ (2013). These days, some researchers are using electroencephalography (EEG) result as another option to detect the stroke disease besides CT Scan image as the gold standard. A previous study on the data of stroke and healthy patients in National Brain Center Hospital (RS PON) used Brain Symmetry Index (BSI), Delta-Alpha Ratio (DAR), and Delta-Theta-Alpha-Beta Ratio (DTABR) as the features for classification by an Extreme Learning Machine (ELM). The study got 85% accuracy with sensitivity above 86 % for acute ischemic stroke detection. Using EEG data means dealing with many data dimensions, and it can reduce the accuracy of classifier (the curse of dimensionality). Principal Component Analysis (PCA) could reduce dimensionality and computation cost without decreasing classification accuracy. XGBoost, as the scalable tree boosting classifier, can solve real-world scale problems (Higgs Boson and Allstate dataset) with using a minimal amount of resources. This paper reuses the same data from RS PON and features from previous research, preprocessed with PCA and classified with XGBoost, to increase the accuracy with fewer electrodes. The specific fewer electrodes improved the accuracy of stroke detection. Our future work will examine the other algorithm besides PCA to get higher accuracy with less number of channels.

  19. Accuracy and Measurement Error of the Medial Clear Space of the Ankle.

    PubMed

    Metitiri, Ogheneochuko; Ghorbanhoseini, Mohammad; Zurakowski, David; Hochman, Mary G; Nazarian, Ara; Kwon, John Y

    2017-04-01

    Measurement of the medial clear space (MCS) is commonly used to assess deltoid ligament competency and mortise stability when managing ankle fractures. Lacking knowledge of the true anatomic width measured, previous studies have been unable to measure accuracy of measurement. The purpose of this study was to determine MCS measurement error and accuracy and any influencing factors. Using 3 normal transtibial ankle cadaver specimens, deltoid and syndesmotic ligaments were transected and the mortise widened and affixed at a width of 6 mm (specimen 1) and 4 mm (specimen 2). The mortise was left intact in specimen 3. Radiographs were obtained of each cadaver at varying degrees of rotation. Radiographs were randomized, and providers measured the MCS using a standardized technique. Lack of accuracy as well as lack of precision in measurement of the medial clear space compared to a known anatomic value was present for all 3 specimens tested. There were no significant differences in mean delta with regard to level of training for specimens 1 and 2; however, with specimen 3, staff physicians showed increased measurement accuracy compared with trainees. Accuracy and precision of MCS measurements are poor. Provider experience did not appear to influence accuracy and precision of measurements for the displaced mortise. This high degree of measurement error and lack of precision should be considered when deciding treatment options based on MCS measurements.

  20. Accuracy assessment of linear spectral mixture model due to terrain undulation

    NASA Astrophysics Data System (ADS)

    Wang, Tianxing; Chen, Songlin; Ma, Ya

    2008-12-01

    Mixture spectra are common in remote sensing due to the limitations of spatial resolution and the heterogeneity of land surface. During the past 30 years, a lot of subpixel model have developed to investigate the information within mixture pixels. Linear spectral mixture model (LSMM) is a simper and more general subpixel model. LSMM also known as spectral mixture analysis is a widely used procedure to determine the proportion of endmembers (constituent materials) within a pixel based on the endmembers' spectral characteristics. The unmixing accuracy of LSMM is restricted by variety of factors, but now the research about LSMM is mostly focused on appraisement of nonlinear effect relating to itself and techniques used to select endmembers, unfortunately, the environment conditions of study area which could sway the unmixing-accuracy, such as atmospheric scatting and terrain undulation, are not studied. This paper probes emphatically into the accuracy uncertainty of LSMM resulting from the terrain undulation. ASTER dataset was chosen and the C terrain correction algorithm was applied to it. Based on this, fractional abundances for different cover types were extracted from both pre- and post-C terrain illumination corrected ASTER using LSMM. Simultaneously, the regression analyses and the IKONOS image were introduced to assess the unmixing accuracy. Results showed that terrain undulation could dramatically constrain the application of LSMM in mountain area. Specifically, for vegetation abundances, a improved unmixing accuracy of 17.6% (regression against to NDVI) and 18.6% (regression against to MVI) for R2 was achieved respectively by removing terrain undulation. Anyway, this study indicated in a quantitative way that effective removal or minimization of terrain illumination effects was essential for applying LSMM. This paper could also provide a new instance for LSMM applications in mountainous areas. In addition, the methods employed in this study could be

  1. Development and validation of a cerebral oximeter capable of absolute accuracy.

    PubMed

    MacLeod, David B; Ikeda, Keita; Vacchiano, Charles; Lobbestael, Aaron; Wahr, Joyce A; Shaw, Andrew D

    2012-12-01

    Cerebral oximetry may be a valuable monitor, but few validation data are available, and most report the change from baseline rather than absolute accuracy, which may be affected by individuals whose oximetric values are outside the expected range. The authors sought to develop and validate a cerebral oximeter capable of absolute accuracy. An in vivo research study. A university human physiology laboratory. Healthy human volunteers were enrolled in calibration and validation studies of 2 cerebral oximetric sensors, the Nonin 8000CA and 8004CA. The 8000CA validation study identified 5 individuals with atypical cerebral oxygenation values; their data were used to design the 8004CA sensor, which subsequently underwent calibration and validation. Volunteers were taken through a stepwise hypoxia protocol to a minimum saturation of peripheral oxygen. Arteriovenous saturation (70% jugular bulb venous saturation and 30% arterial saturation) at 6 hypoxic plateaus was used as the reference value for the cerebral oximeter. Absolute accuracy was defined using a combination of the bias and precision of the paired saturations (A(RMS)). In the validation study for the 8000CA sensor (n = 9, 106 plateaus), relative accuracy was an A(RMS) of 2.7, with an absolute accuracy of 8.1, meeting the criteria for a relative (trend) monitor, but not an absolute monitor. In the validation study for the 8004CA sensor (n = 11, 119 plateaus), the A(RMS) of the 8004CA was 4.1, meeting the prespecified success criterion of <5.0. The Nonin cerebral oximeter using the 8004CA sensor can provide absolute data on regional cerebral saturation compared with arteriovenous saturation, even in subjects previously shown to have values outside the normal population distribution curves. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Indicators of accuracy of consumer health information on the Internet: a study of indicators relating to information for managing fever in children in the home.

    PubMed

    Fallis, Don; Frické, Martin

    2002-01-01

    To identify indicators of accuracy for consumer health information on the Internet. The results will help lay people distinguish accurate from inaccurate health information on the Internet. Several popular search engines (Yahoo, AltaVista, and Google) were used to find Web pages on the treatment of fever in children. The accuracy and completeness of these Web pages was determined by comparing their content with that of an instrument developed from authoritative sources on treating fever in children. The presence on these Web pages of a number of proposed indicators of accuracy, taken from published guidelines for evaluating the quality of health information on the Internet, was noted. Correlation between the accuracy of Web pages on treating fever in children and the presence of proposed indicators of accuracy on these pages. Likelihood ratios for the presence (and absence) of these proposed indicators. One hundred Web pages were identified and characterized as "more accurate" or "less accurate." Three indicators correlated with accuracy: displaying the HONcode logo, having an organization domain, and displaying a copyright. Many proposed indicators taken from published guidelines did not correlate with accuracy (e.g., the author being identified and the author having medical credentials) or inaccuracy (e.g., lack of currency and advertising). This method provides a systematic way of identifying indicators that are correlated with the accuracy (or inaccuracy) of health information on the Internet. Three such indicators have been identified in this study. Identifying such indicators and informing the providers and consumers of health information about them would be valuable for public health care.

  3. Evaluation of approaches for estimating the accuracy of genomic prediction in plant breeding.

    PubMed

    Ould Estaghvirou, Sidi Boubacar; Ogutu, Joseph O; Schulz-Streeck, Torben; Knaak, Carsten; Ouzunova, Milena; Gordillo, Andres; Piepho, Hans-Peter

    2013-12-06

    In genomic prediction, an important measure of accuracy is the correlation between the predicted and the true breeding values. Direct computation of this quantity for real datasets is not possible, because the true breeding value is unknown. Instead, the correlation between the predicted breeding values and the observed phenotypic values, called predictive ability, is often computed. In order to indirectly estimate predictive accuracy, this latter correlation is usually divided by an estimate of the square root of heritability. In this study we use simulation to evaluate estimates of predictive accuracy for seven methods, four (1 to 4) of which use an estimate of heritability to divide predictive ability computed by cross-validation. Between them the seven methods cover balanced and unbalanced datasets as well as correlated and uncorrelated genotypes. We propose one new indirect method (4) and two direct methods (5 and 6) for estimating predictive accuracy and compare their performances and those of four other existing approaches (three indirect (1 to 3) and one direct (7)) with simulated true predictive accuracy as the benchmark and with each other. The size of the estimated genetic variance and hence heritability exerted the strongest influence on the variation in the estimated predictive accuracy. Increasing the number of genotypes considerably increases the time required to compute predictive accuracy by all the seven methods, most notably for the five methods that require cross-validation (Methods 1, 2, 3, 4 and 6). A new method that we propose (Method 5) and an existing method (Method 7) used in animal breeding programs were the fastest and gave the least biased, most precise and stable estimates of predictive accuracy. Of the methods that use cross-validation Methods 4 and 6 were often the best. The estimated genetic variance and the number of genotypes had the greatest influence on predictive accuracy. Methods 5 and 7 were the fastest and produced the least

  4. Instantaneous wave-free ratio as an alternative to fractional flow reserve in assessment of moderate coronary stenoses: A meta-analysis of diagnostic accuracy studies.

    PubMed

    Maini, Rohit; Moscona, John; Katigbak, Paul; Fernandez, Camilo; Sidhu, Gursukhmandeep; Saleh, Qusai; Irimpen, Anand; Samson, Rohan; LeJemtel, Thierry

    2017-12-27

    Fractional flow reserve (FFR) remains underutilized due to practical concerns related to the need for hyperemic agents. These concerns have prompted the study of instantaneous wave-free ratio (iFR), a vasodilator-free index of coronary stenosis. Non-inferior cardiovascular outcomes have been demonstrated in two recent randomized clinic trials. We performed this meta-analysis to provide a necessary update of the diagnostic accuracy of iFR referenced to FFR based on the addition of eight more recent studies and 3727 more lesions. We searched the PubMed, EMBASE, Central, ProQuest, and Web of Science databases for full text articles published through May 31, 2017 to identify studies addressing the diagnostic accuracy of iFR referenced to FFR≤0.80. The following keywords were used: "instantaneous wave-free ratio" OR "iFR" AND "fractional flow reserve" OR "FFR." In total, 16 studies comprising 5756 lesions were identified. Pooled diagnostic accuracy estimates of iFR versus FFR≤0.80 were: sensitivity, 0.78 (95% CI, 0.76-0.79); specificity, 0.83 (0.81-0.84); positive likelihood ratio, 4.54 (3.85-5.35); negative likelihood ratio, 0.28 (0.24-0.32); diagnostic odds ratio, 17.38 (14.16-21.34); area under the summary receiver-operating characteristic curve, 0.87; and an overall diagnostic accuracy of 0.81 (0.78-0.84). In conclusion, iFR showed excellent agreement with FFR as a resting index of coronary stenosis severity without the undesired effects and cost of hyperemic agents. When considering along with its clinical outcome data and ease of application, the diagnostic accuracy of iFR supports its use as a suitable alternative to FFR for physiology-guided revascularization of moderate coronary stenoses. We performed a meta-analysis of the diagnostic accuracy of iFR referenced to FFR. iFR showed excellent agreement with FFR as a resting index of coronary stenosis severity without the undesired effects and cost of hyperemic agents. This supports its use as a suitable

  5. Prompting methods affect the accuracy of children's school lunch recalls.

    PubMed

    Baxter, S D; Thompson, W O; Davis, H C

    2000-08-01

    To evaluate the feasibility of implementing 3 specific prompting methods among students in the first and fourth grades (mean age = 7.2 and 10.1 years, respectively), to validate recall accuracy of first- and fourth-grade students against observation, to develop a single measure of inaccuracy that cumulated errors in reporting food items and amounts without allowing underreporting and overreporting to cancel each other, and to establish information regarding the measure of inaccuracy for use in future studies. Children were interviewed the morning after they were observed eating lunch provided by the school. Interviews included free recall, nonsuggestive prompted recall, and specific prompted recall (either preference, food category, or visual). Ninety-six children (48 students per grade) were studied--32 per the specific prompting method--stratified by grade, sex, and ethnicity (African-American or white). Specific prompting method was randomly assigned to children within strata. Food items were categorized and weighted as: combination entree = 2, condiments = 1/3, and other = 1. To calculate inaccuracy of recall, absolute differences between amounts reported and observed eaten were calculated for each item and then multiplied by each item's weight; these values were then summed across all items for each child. Inaccuracy of recall was determined before specific prompting and after specific prompting and for the difference (inaccuracy after specific prompting minus inaccuracy before specific prompting). Before specific prompting, median inaccuracy was 2.7 servings for the 48 first-grade students and 1.7 servings for the 48 fourth-grade students. The median difference in inaccuracy from before to after specific prompting was 0 for both grades. Specific prompting increased recall accuracy for 9 first-graders and 12 fourth-graders, but decreased recall accuracy for 21 first-graders and 7 fourth-graders, and did not change recall accuracy for 18 first-graders and 29

  6. Increasing Accuracy in Computed Inviscid Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Dyson, Roger

    2004-01-01

    A technique has been devised to increase the accuracy of computational simulations of flows of inviscid fluids by increasing the accuracy with which surface boundary conditions are represented. This technique is expected to be especially beneficial for computational aeroacoustics, wherein it enables proper accounting, not only for acoustic waves, but also for vorticity and entropy waves, at surfaces. Heretofore, inviscid nonlinear surface boundary conditions have been limited to third-order accuracy in time for stationary surfaces and to first-order accuracy in time for moving surfaces. For steady-state calculations, it may be possible to achieve higher accuracy in space, but high accuracy in time is needed for efficient simulation of multiscale unsteady flow phenomena. The present technique is the first surface treatment that provides the needed high accuracy through proper accounting of higher-order time derivatives. The present technique is founded on a method known in art as the Hermitian modified solution approximation (MESA) scheme. This is because high time accuracy at a surface depends upon, among other things, correction of the spatial cross-derivatives of flow variables, and many of these cross-derivatives are included explicitly on the computational grid in the MESA scheme. (Alternatively, a related method other than the MESA scheme could be used, as long as the method involves consistent application of the effects of the cross-derivatives.) While the mathematical derivation of the present technique is too lengthy and complex to fit within the space available for this article, the technique itself can be characterized in relatively simple terms: The technique involves correction of surface-normal spatial pressure derivatives at a boundary surface to satisfy the governing equations and the boundary conditions and thereby achieve arbitrarily high orders of time accuracy in special cases. The boundary conditions can now include a potentially infinite number

  7. Stereotype Accuracy: Toward Appreciating Group Differences.

    ERIC Educational Resources Information Center

    Lee, Yueh-Ting, Ed.; And Others

    The preponderance of scholarly theory and research on stereotypes assumes that they are bad and inaccurate, but understanding stereotype accuracy and inaccuracy is more interesting and complicated than simpleminded accusations of racism or sexism would seem to imply. The selections in this collection explore issues of the accuracy of stereotypes…

  8. Factors Influencing Science Content Accuracy in Elementary Inquiry Science Lessons

    NASA Astrophysics Data System (ADS)

    Nowicki, Barbara L.; Sullivan-Watts, Barbara; Shim, Minsuk K.; Young, Betty; Pockalny, Robert

    2013-06-01

    Elementary teachers face increasing demands to engage children in authentic science process and argument while simultaneously preparing them with knowledge of science facts, vocabulary, and concepts. This reform is particularly challenging due to concerns that elementary teachers lack adequate science background to teach science accurately. This study examined 81 in-classroom inquiry science lessons for preservice education majors and their cooperating teachers to determine the accuracy of the science content delivered in elementary classrooms. Our results showed that 74 % of experienced teachers and 50 % of student teachers presented science lessons with greater than 90 % accuracy. Eleven of the 81 lessons (9 preservice, 2 cooperating teachers) failed to deliver accurate science content to the class. Science content accuracy was highly correlated with the use of kit-based resources supported with professional development, a preference for teaching science, and grade level. There was no correlation between the accuracy of science content and some common measures of teacher content knowledge (i.e., number of college science courses, science grades, or scores on a general science content test). Our study concluded that when provided with high quality curricular materials and targeted professional development, elementary teachers learn needed science content and present it accurately to their students.

  9. Destination memory accuracy and confidence in younger and older adults.

    PubMed

    Johnson, Tara L; Jefferson, Susan C

    2018-01-01

    Background/Study Context: Nascent research on destination memory-remembering to whom we tell particular information-suggested that older adults have deficits in destination memory and are more confident on inaccurate responses than younger adults. This study assessed the effects of age, attentional resources, and mental imagery on destination memory accuracy and confidence in younger and older adults. Using computer format, participants told facts to pictures of famous people in one of four conditions (control, self-focus, refocus, imagery). Older adults had lower destination memory accuracy than younger adults, driven by a higher level of false alarms. Whereas younger adults were more confident in accurate answers, older adults were more confident in inaccurate answers. Accuracy across participants was lowest when attention was directed internally but significantly improved when mental imagery was used. Importantly, the age-related differences in false alarms and high-confidence inaccurate answers disappeared when imagery was used. Older adults are more likely than younger adults to commit destination memory errors and are less accurate in related confidence judgments. Furthermore, the use of associative memory strategies may help improve destination memory across age groups, improve the accuracy of confidence judgments in older adults, and decrease age-related destination memory impairment, particularly in young-old adults.

  10. 40 CFR 92.127 - Emission measurement accuracy.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

  11. 40 CFR 92.127 - Emission measurement accuracy.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

  12. 40 CFR 92.127 - Emission measurement accuracy.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

  13. 40 CFR 92.127 - Emission measurement accuracy.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

  14. 40 CFR 92.127 - Emission measurement accuracy.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Emission measurement accuracy. (a) Good engineering practice dictates that exhaust emission sample analyzer... resolution read-out systems such as computers, data loggers, etc., can provide sufficient accuracy and...

  15. Improved accuracies for satellite tracking

    NASA Technical Reports Server (NTRS)

    Kammeyer, P. C.; Fiala, A. D.; Seidelmann, P. K.

    1991-01-01

    A charge coupled device (CCD) camera on an optical telescope which follows the stars can be used to provide high accuracy comparisons between the line of sight to a satellite, over a large range of satellite altitudes, and lines of sight to nearby stars. The CCD camera can be rotated so the motion of the satellite is down columns of the CCD chip, and charge can be moved from row to row of the chip at a rate which matches the motion of the optical image of the satellite across the chip. Measurement of satellite and star images, together with accurate timing of charge motion, provides accurate comparisons of lines of sight. Given lines of sight to stars near the satellite, the satellite line of sight may be determined. Initial experiments with this technique, using an 18 cm telescope, have produced TDRS-4 observations which have an rms error of 0.5 arc second, 100 m at synchronous altitude. Use of a mosaic of CCD chips, each having its own rate of charge motion, in the focal place of a telescope would allow point images of a geosynchronous satellite and of stars to be formed simultaneously in the same telescope. The line of sight of such a satellite could be measured relative to nearby star lines of sight with an accuracy of approximately 0.03 arc second. Development of a star catalog with 0.04 arc second rms accuracy and perhaps ten stars per square degree would allow determination of satellite lines of sight with 0.05 arc second rms absolute accuracy, corresponding to 10 m at synchronous altitude. Multiple station time transfers through a communications satellite can provide accurate distances from the satellite to the ground stations. Such observations can, if calibrated for delays, determine satellite orbits to an accuracy approaching 10 m rms.

  16. [The role of ¹⁸F-FDG PET/CT for detecting nodal metastases in cN0 head neck cancer patients:a Meta-analysis].

    PubMed

    Li, X Y; Sun, C L; Du, X D

    2018-05-01

    Objective: The aim of this study is to evaluate the accuracy of ¹⁸F-fluorodeoxyglucose PET/CT(¹⁸F-FDG PET/CT) for the diagnosis of cervical node metastases in cN0 head neck cancer patients. Method: An electronic database search(PubMed,EMBASE,Cochrane Library,WanFang and CNKI databases)was performed. Updated quality assessment of diagnostic accuracy studies-2(QUADAS-2) was used to assess study quality. Data analyses were performed with Meta-Disc1.4. Result: Eight studies were included in the present Meta-analysis. For patient-specific data,the pooled sensitivity,specificity,diagnostic odds ratio(DOR),positive likelihood ratio(PLR),and negative likelihood(NLR)for ¹⁸F-FDG PET/CT were 0.61(95% CI 0.52-0.69),0.74(95% CI 0.68-0.78),9.62(95% CI 2.49-37.22),3.22(95% CI 1.55-6.71),and 0.42(95% CI 0.24-0.37),respectively. The area under the curve(AUC)was 0.804 1.The evaluation of heterogeneity,calculated the pooled diagnostic odds ratio,gave a Q value of 21.26( P <0.05)and an I²of 81.2%. Conclusion: The results of meta-analysis suggested that ¹⁸F-FDG PET/CT did not provide better diagnostic accuracy than CT/MRI in detecting cervical node metastases in cN0 head and neck cancer. Considering the high heterogeneity of the included studies,potential value of PET/CT needs to be validated in future studies. Copyright© by the Editorial Department of Journal of Clinical Otorhinolaryngology Head and Neck Surgery.

  17. On Accuracy of Adaptive Grid Methods for Captured Shocks

    NASA Technical Reports Server (NTRS)

    Yamaleev, Nail K.; Carpenter, Mark H.

    2002-01-01

    The accuracy of two grid adaptation strategies, grid redistribution and local grid refinement, is examined by solving the 2-D Euler equations for the supersonic steady flow around a cylinder. Second- and fourth-order linear finite difference shock-capturing schemes, based on the Lax-Friedrichs flux splitting, are used to discretize the governing equations. The grid refinement study shows that for the second-order scheme, neither grid adaptation strategy improves the numerical solution accuracy compared to that calculated on a uniform grid with the same number of grid points. For the fourth-order scheme, the dominant first-order error component is reduced by the grid adaptation, while the design-order error component drastically increases because of the grid nonuniformity. As a result, both grid adaptation techniques improve the numerical solution accuracy only on the coarsest mesh or on very fine grids that are seldom found in practical applications because of the computational cost involved. Similar error behavior has been obtained for the pressure integral across the shock. A simple analysis shows that both grid adaptation strategies are not without penalties in the numerical solution accuracy. Based on these results, a new grid adaptation criterion for captured shocks is proposed.

  18. Improving IMES Localization Accuracy by Integrating Dead Reckoning Information

    PubMed Central

    Fujii, Kenjiro; Arie, Hiroaki; Wang, Wei; Kaneko, Yuto; Sakamoto, Yoshihiro; Schmitz, Alexander; Sugano, Shigeki

    2016-01-01

    Indoor positioning remains an open problem, because it is difficult to achieve satisfactory accuracy within an indoor environment using current radio-based localization technology. In this study, we investigate the use of Indoor Messaging System (IMES) radio for high-accuracy indoor positioning. A hybrid positioning method combining IMES radio strength information and pedestrian dead reckoning information is proposed in order to improve IMES localization accuracy. For understanding the carrier noise ratio versus distance relation for IMES radio, the signal propagation of IMES radio is modeled and identified. Then, trilateration and extended Kalman filtering methods using the radio propagation model are developed for position estimation. These methods are evaluated through robot localization and pedestrian localization experiments. The experimental results show that the proposed hybrid positioning method achieved average estimation errors of 217 and 1846 mm in robot localization and pedestrian localization, respectively. In addition, in order to examine the reason for the positioning accuracy of pedestrian localization being much lower than that of robot localization, the influence of the human body on the radio propagation is experimentally evaluated. The result suggests that the influence of the human body can be modeled. PMID:26828492

  19. Accuracy of complete-arch model using an intraoral video scanner: An in vitro study.

    PubMed

    Jeong, Il-Do; Lee, Jae-Jun; Jeon, Jin-Hun; Kim, Ji-Hwan; Kim, Hae-Young; Kim, Woong-Chul

    2016-06-01

    Information on the accuracy of intraoral video scanners for long-span areas is limited. The purpose of this in vitro study was to evaluate and compare the trueness and precision of an intraoral video scanner, an intraoral still image scanner, and a blue-light scanner for the production of digital impressions. Reference scan data were obtained by scanning a complete-arch model. An identical model was scanned 8 times using an intraoral video scanner (CEREC Omnicam; Sirona) and an intraoral still image scanner (CEREC Bluecam; Sirona), and stone casts made from conventional impressions of the same model were scanned 8 times with a blue-light scanner as a control (Identica Blue; Medit). Accuracy consists of trueness (the extent to which the scan data differ from the reference scan) and precision (the similarity of the data from multiple scans). To evaluate precision, 8 scans were superimposed using 3-dimensional analysis software; the reference scan data were then superimposed to determine the trueness. Differences were analyzed using 1-way ANOVA and post hoc Tukey HSD tests (α=.05). Trueness in the video scanner group was not significantly different from that in the control group. However, the video scanner group showed significantly lower values than those of the still image scanner group for all variables (P<.05), except in tolerance range. The root mean square, standard deviations, and mean negative precision values for the video scanner group were significantly higher than those for the other groups (P<.05). Digital impressions obtained by the intraoral video scanner showed better accuracy for long-span areas than those captured by the still image scanner. However, the video scanner was less accurate than the laboratory scanner. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  20. Developing a weighted measure of speech sound accuracy.

    PubMed

    Preston, Jonathan L; Ramsdell, Heather L; Oller, D Kimbrough; Edwards, Mary Louise; Tobin, Stephen J

    2011-02-01

    To develop a system for numerically quantifying a speaker's phonetic accuracy through transcription-based measures. With a focus on normal and disordered speech in children, the authors describe a system for differentially weighting speech sound errors on the basis of various levels of phonetic accuracy using a Weighted Speech Sound Accuracy (WSSA) score. The authors then evaluate the reliability and validity of this measure. Phonetic transcriptions were analyzed from several samples of child speech, including preschoolers and young adolescents with and without speech sound disorders and typically developing toddlers. The new measure of phonetic accuracy was validated against existing measures, was used to discriminate typical and disordered speech production, and was evaluated to examine sensitivity to changes in phonetic accuracy over time. Reliability between transcribers and consistency of scores among different word sets and testing points are compared. Initial psychometric data indicate that WSSA scores correlate with other measures of phonetic accuracy as well as listeners' judgments of the severity of a child's speech disorder. The measure separates children with and without speech sound disorders and captures growth in phonetic accuracy in toddlers' speech over time. The measure correlates highly across transcribers, word lists, and testing points. Results provide preliminary support for the WSSA as a valid and reliable measure of phonetic accuracy in children's speech.

  1. Accuracy and eligibility of CBCT to digitize dental plaster casts.

    PubMed

    Becker, Kathrin; Schmücker, Ulf; Schwarz, Frank; Drescher, Dieter

    2018-05-01

    Software-based dental planning requires digital casts and oftentimes cone-beam computed tomography (CBCT) radiography. However, buying a dedicated model digitizing device can be expensive and might not be required. The present study aimed to assess whether digital models derived from CBCT and models digitized using a dedicated optical device are of comparable accuracy. A total of 20 plaster casts were digitized with eight CBCT and five optical model digitizers. Corresponding models were superimposed using six control points and subsequent iterative closest point matching. Median distances were calculated among all registered models. Data were pooled per scanner and model. Boxplots were generated, and the paired t test, a Friedman test, and a post-hoc Nemenyi test were employed for statistical comparison. Results were found significant at p < 0.05. All CBCT devices allowed the digitization of plaster casts, but failed to reach the accuracy of the dedicated model digitizers (p < 0.001). Median distances between CBCT and optically digitized casts were 0.064 + - 0.005 mm. Qualitative differences among the CBCT systems were detected (χ 2  = 78.07, p < 0.001), and one CBCT providing a special plaster cast digitization mode was found superior to the competitors (p < 0.05). CBCT systems failed to reach the accuracy from optical digitizers, but within the limits of the study, accuracy appeared to be sufficient for digital planning and forensic purposes. Most CBCT systems enabled digitization of plaster casts, and accuracy was found sufficient for digital planning and storage purposes.

  2. Fundamental Importance of Reference Glucose Analyzer Accuracy for Evaluating the Performance of Blood Glucose Monitoring Systems (BGMSs)

    PubMed Central

    Bailey, Timothy S.; Klaff, Leslie J.; Wallace, Jane F.; Greene, Carmine; Pardo, Scott; Harrison, Bern; Simmons, David A.

    2016-01-01

    Background: As blood glucose monitoring system (BGMS) accuracy is based on comparison of BGMS and laboratory reference glucose analyzer results, reference instrument accuracy is important to discriminate small differences between BGMS and reference glucose analyzer results. Here, we demonstrate the important role of reference glucose analyzer accuracy in BGMS accuracy evaluations. Methods: Two clinical studies assessed the performance of a new BGMS, using different reference instrument procedures. BGMS and YSI analyzer results were compared for fingertip blood that was obtained by untrained subjects’ self-testing and study staff testing, respectively. YSI analyzer accuracy was monitored using traceable serum controls. Results: In study 1 (N = 136), 94.1% of BGMS results were within International Organization for Standardization (ISO) 15197:2013 accuracy criteria; YSI analyzer serum control results showed a negative bias (−0.64% to −2.48%) at the first site and a positive bias (3.36% to 6.91%) at the other site. In study 2 (N = 329), 97.8% of BGMS results were within accuracy criteria; serum controls showed minimal bias (<0.92%) at both sites. Conclusions: These findings suggest that the ability to demonstrate that a BGMS meets accuracy guidelines is influenced by reference instrument accuracy. PMID:26902794

  3. Improved Motor-Timing: Effects of Synchronized Metro-Nome Training on Golf Shot Accuracy

    PubMed Central

    Sommer, Marius; Rönnqvist, Louise

    2009-01-01

    This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. Twenty-six experienced male golfers participated (mean age 27 years; mean golf handicap 12.6) in this study. Pre- and post-test investigations of golf shots made by three different clubs were conducted by use of a golf simulator. The golfers were randomized into two groups: a SMT group and a Control group. After the pre-test, the golfers in the SMT group completed a 4-week SMT program designed to improve their motor timing, the golfers in the Control group were merely training their golf-swings during the same time period. No differences between the two groups were found from the pre-test outcomes, either for motor timing scores or for golf shot accuracy. However, the post-test results after the 4-weeks SMT showed evident motor timing improvements. Additionally, significant improvements for golf shot accuracy were found for the SMT group and with less variability in their performance. No such improvements were found for the golfers in the Control group. As with previous studies that used a SMT program, this study’s results provide further evidence that motor timing can be improved by SMT and that such timing improvement also improves golf accuracy. Key points This study investigates the effect of synchronized metronome training (SMT) on motor timing and how this training might affect golf shot accuracy. A randomized control group design was used. The 4 week SMT intervention showed significant improvements in motor timing, golf shot accuracy, and lead to less variability. We conclude that this study’s results provide further evidence that motor timing can be improved by SMT training and that such timing improvement also improves golf accuracy. PMID:24149608

  4. Cued Speech Transliteration: Effects of Speaking Rate and Lag Time on Production Accuracy.

    PubMed

    Krause, Jean C; Tessler, Morgan P

    2016-10-01

    Many deaf and hard-of-hearing children rely on interpreters to access classroom communication. Although the exact level of access provided by interpreters in these settings is unknown, it is likely to depend heavily on interpreter accuracy (portion of message correctly produced by the interpreter) and the factors that govern interpreter accuracy. In this study, the accuracy of 12 Cued Speech (CS) transliterators with varying degrees of experience was examined at three different speaking rates (slow, normal, fast). Accuracy was measured with a high-resolution, objective metric in order to facilitate quantitative analyses of the effect of each factor on accuracy. Results showed that speaking rate had a large negative effect on accuracy, caused primarily by an increase in omitted cues, whereas the effect of lag time on accuracy, also negative, was quite small and explained just 3% of the variance. Increased experience level was generally associated with increased accuracy; however, high levels of experience did not guarantee high levels of accuracy. Finally, the overall accuracy of the 12 transliterators, 54% on average across all three factors, was low enough to raise serious concerns about the quality of CS transliteration services that (at least some) children receive in educational settings. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. The accuracy of new wheelchair users' predictions about their future wheelchair use.

    PubMed

    Hoenig, Helen; Griffiths, Patricia; Ganesh, Shanti; Caves, Kevin; Harris, Frances

    2012-06-01

    This study examined the accuracy of new wheelchair user predictions about their future wheelchair use. This was a prospective cohort study of 84 community-dwelling veterans provided a new manual wheelchair. The association between predicted and actual wheelchair use was strong at 3 mos (ϕ coefficient = 0.56), with 90% of those who anticipated using the wheelchair at 3 mos still using it (i.e., positive predictive value = 0.96) and 60% of those who anticipated not using it indeed no longer using the wheelchair (i.e., negative predictive value = 0.60, overall accuracy = 0.92). Predictive accuracy diminished over time, with overall accuracy declining from 0.92 at 3 mos to 0.66 at 6 mos. At all time points, and for all types of use, patients better predicted use as opposed to disuse, with correspondingly higher positive than negative predictive values. Accuracy of prediction of use in specific indoor and outdoor locations varied according to location. This study demonstrates the importance of better understanding the potential mismatch between the anticipated and actual patterns of wheelchair use. The findings suggest that users can be relied upon to accurately predict their basic wheelchair-related needs in the short-term. Further exploration is needed to identify characteristics that will aid users and their providers in more accurately predicting mobility needs for the long-term.

  6. Accuracy of genomic selection in European maize elite breeding populations.

    PubMed

    Zhao, Yusheng; Gowda, Manje; Liu, Wenxin; Würschum, Tobias; Maurer, Hans P; Longin, Friedrich H; Ranc, Nicolas; Reif, Jochen C

    2012-03-01

    Genomic selection is a promising breeding strategy for rapid improvement of complex traits. The objective of our study was to investigate the prediction accuracy of genomic breeding values through cross validation. The study was based on experimental data of six segregating populations from a half-diallel mating design with 788 testcross progenies from an elite maize breeding program. The plants were intensively phenotyped in multi-location field trials and fingerprinted with 960 SNP markers. We used random regression best linear unbiased prediction in combination with fivefold cross validation. The prediction accuracy across populations was higher for grain moisture (0.90) than for grain yield (0.58). The accuracy of genomic selection realized for grain yield corresponds to the precision of phenotyping at unreplicated field trials in 3-4 locations. As for maize up to three generations are feasible per year, selection gain per unit time is high and, consequently, genomic selection holds great promise for maize breeding programs.

  7. Brain temperature measurement: A study of in vitro accuracy and stability of smart catheter temperature sensors.

    PubMed

    Li, Chunyan; Wu, Pei-Ming; Wu, Zhizhen; Ahn, Chong H; LeDoux, David; Shutter, Lori A; Hartings, Jed A; Narayan, Raj K

    2012-02-01

    The injured brain is vulnerable to increases in temperature after severe head injury. Therefore, accurate and reliable measurement of brain temperature is important to optimize patient outcome. In this work, we have fabricated, optimized and characterized temperature sensors for use with a micromachined smart catheter for multimodal intracranial monitoring. Developed temperature sensors have resistance of 100.79 ± 1.19Ω and sensitivity of 67.95 mV/°C in the operating range from15-50°C, and time constant of 180 ms. Under the optimized excitation current of 500 μA, adequate signal-to-noise ratio was achieved without causing self-heating, and changes in immersion depth did not introduce clinically significant errors of measurements (<0.01°C). We evaluated the accuracy and long-term drift (5 days) of twenty temperature sensors in comparison to two types of commercial temperature probes (USB Reference Thermometer, NIST-traceable bulk probe with 0.05°C accuracy; and IT-21, type T type clinical microprobe with guaranteed 0.1°C accuracy) under controlled laboratory conditions. These in vitro experimental data showed that the temperature measurement performance of our sensors was accurate and reliable over the course of 5 days. The smart catheter temperature sensors provided accuracy and long-term stability comparable to those of commercial tissue-implantable microprobes, and therefore provide a means for temperature measurement in a microfabricated, multimodal cerebral monitoring device.

  8. Study on Classification Accuracy Inspection of Land Cover Data Aided by Automatic Image Change Detection Technology

    NASA Astrophysics Data System (ADS)

    Xie, W.-J.; Zhang, L.; Chen, H.-P.; Zhou, J.; Mao, W.-J.

    2018-04-01

    The purpose of carrying out national geographic conditions monitoring is to obtain information of surface changes caused by human social and economic activities, so that the geographic information can be used to offer better services for the government, enterprise and public. Land cover data contains detailed geographic conditions information, thus has been listed as one of the important achievements in the national geographic conditions monitoring project. At present, the main issue of the production of the land cover data is about how to improve the classification accuracy. For the land cover data quality inspection and acceptance, classification accuracy is also an important check point. So far, the classification accuracy inspection is mainly based on human-computer interaction or manual inspection in the project, which are time consuming and laborious. By harnessing the automatic high-resolution remote sensing image change detection technology based on the ERDAS IMAGINE platform, this paper carried out the classification accuracy inspection test of land cover data in the project, and presented a corresponding technical route, which includes data pre-processing, change detection, result output and information extraction. The result of the quality inspection test shows the effectiveness of the technical route, which can meet the inspection needs for the two typical errors, that is, missing and incorrect update error, and effectively reduces the work intensity of human-computer interaction inspection for quality inspectors, and also provides a technical reference for the data production and quality control of the land cover data.

  9. Evaluation and comparison of dimensional accuracy of newly introduced elastomeric impression material using 3D laser scanners: an in vitro study.

    PubMed

    Pandita, Amrita; Jain, Teerthesh; Yadav, Naveen S; Feroz, S M A; Pradeep; Diwedi, Akankasha

    2013-03-01

    Aim of the present study was to comparatively evaluate dimensional accuracy of newely introduced elastomeric impression material after repeated pours at different time intervals. In the present study a total of 20 (10 + 10) impressions of master model were made from vinyl polyether silicone and vinyl polysiloxane impression material. Each impression was repeatedly poured at 1, 24 hours and 14 days. Therefore, a total of 60 casts were obtained. Casts obtained were scanned with three-dimensional (3D) laser scanner and measurements were done. Vinyl polyether silicone produced overall undersized dies, with greatest change being 0.14% only after 14 days. Vinyl polysiloxane produced smaller dies after 1 and 24 hours and larger dies after 14 days, differing from master model by only 0.07% for the smallest die and to 0.02% for the largest die. All the deviations measured from the master model with both the impression materials were within a clinically acceptable range. In a typical fixed prosthodontic treatment accuracy of prosthesis is critical as it determines the success, failure and the prognosis of treatment including abutments. This is mainly dependent upon fit of prosthesis which in turn is dependent on dimensional accuracy of dies, poured from elastomeric impressions.

  10. Long-term recall accuracy for mobile phone calls in young Japanese people: A follow-up validation study using software-modified phones.

    PubMed

    Kiyohara, Kosuke; Wake, Kanako; Watanabe, Soichi; Arima, Takuji; Sato, Yasuto; Kojimahara, Noriko; Taki, Masao; Cardis, Elisabeth; Yamaguchi, Naohito

    2018-03-01

    This study examined changes in recall accuracy for mobile phone calls over a long period. Japanese students' actual call statuses were monitored for 1 month using software-modified phones (SMPs). Three face-to-face interviews were conducted to obtain information regarding self-reported call status during the monitoring period: first interview: immediately after the monitoring period; second interview: after 10-12 months; third interview: after 48-55 months. Using the SMP records as the "gold standard", phone call recall accuracy was assessed for each interview. Data for 94 participants were analyzed. The number of calls made was underestimated considerably and the duration of calls was overestimated slightly in all interviews. Agreement between self-report and SMP records regarding the number of calls, duration of calls and laterality (i.e., use of the dominant ear while making calls) gradually deteriorated with the increase in the interval following the monitoring period (number of calls: first interview: Pearson's r=0.641, third interview: 0.396; duration of calls: first interview: Pearson's r=0.763, third interview: 0.356; laterality: first interview: weighted-κ=0.677, third interview: 0.448). Thus, recall accuracy for mobile phone calls would be consistently imperfect over a long period, and the results of related epidemiological studies should be interpreted carefully.

  11. Using additive manufacturing in accuracy evaluation of reconstructions from computed tomography.

    PubMed

    Smith, Erin J; Anstey, Joseph A; Venne, Gabriel; Ellis, Randy E

    2013-05-01

    Bone models derived from patient imaging and fabricated using additive manufacturing technology have many potential uses including surgical planning, training, and research. This study evaluated the accuracy of bone surface reconstruction of two diarthrodial joints, the hip and shoulder, from computed tomography. Image segmentation of the tomographic series was used to develop a three-dimensional virtual model, which was fabricated using fused deposition modelling. Laser scanning was used to compare cadaver bones, printed models, and intermediate segmentations. The overall bone reconstruction process had a reproducibility of 0.3 ± 0.4 mm. Production of the model had an accuracy of 0.1 ± 0.1 mm, while the segmentation had an accuracy of 0.3 ± 0.4 mm, indicating that segmentation accuracy was the key factor in reconstruction. Generally, the shape of the articular surfaces was reproduced accurately, with poorer accuracy near the periphery of the articular surfaces, particularly in regions with periosteum covering and where osteophytes were apparent.

  12. Accuracy of lung cancer ICD-9-CM codes in Umbria, Napoli 3 Sud and Friuli Venezia Giulia administrative healthcare databases: a diagnostic accuracy study

    PubMed Central

    Montedori, Alessandro; Bidoli, Ettore; Serraino, Diego; Fusco, Mario; Giovannini, Gianni; Casucci, Paola; Franchini, David; Granata, Annalisa; Ciullo, Valerio; Vitale, Maria Francesca; Gobbato, Michele; Chiari, Rita; Cozzolino, Francesco; Orso, Massimiliano; Orlandi, Walter

    2018-01-01

    Objectives To assess the accuracy of International Classification of Diseases 9th Revision–Clinical Modification (ICD-9-CM) codes in identifying subjects with lung cancer. Design A cross-sectional diagnostic accuracy study comparing ICD-9-CM 162.x code (index test) in primary position with medical chart (reference standard). Case ascertainment was based on the presence of a primary nodular lesion in the lung and cytological or histological documentation of cancer from a primary or metastatic site. Setting Three operative units: administrative databases from Umbria Region (890 000 residents), ASL Napoli 3 Sud (NA) (1 170 000 residents) and Friuli Venezia Giulia (FVG) Region (1 227 000 residents). Participants Incident subjects with lung cancer (n=386) diagnosed in primary position between 2012 and 2014 and a population of non-cases (n=280). Outcome measures Sensitivity, specificity and positive predictive value (PPV) for 162.x code. Results 130 cases and 94 non-cases were randomly selected from each database and the corresponding medical charts were reviewed. Most of the diagnoses for lung cancer were performed in medical departments. True positive rates were high for all the three units. Sensitivity was 99% (95% CI 95% to 100%) for Umbria, 97% (95% CI 91% to 100%) for NA, and 99% (95% CI 95% to 100%) for FVG. The false positive rates were 24%, 37% and 23% for Umbria, NA and FVG, respectively. PPVs were 79% (73% to 83%)%) for Umbria, 58% (53% to 63%)%) for NA and 79% (73% to 84%)%) for FVG. Conclusions Case ascertainment for lung cancer based on imaging or endoscopy associated with histological examination yielded an excellent sensitivity in all the three administrative databases. PPV was moderate for Umbria and FVG but lower for NA. PMID:29773701

  13. Systematic Review of the Diagnostic Accuracy and Therapeutic Effectiveness of Sacroiliac Joint Interventions.

    PubMed

    Simopoulos, Thomas T; Manchikanti, Laxmaiah; Gupta, Sanjeeva; Aydin, Steve M; Kim, Chong Hwan; Solanki, Daneshvari; Nampiaparampil, Devi E; Singh, Vijay; Staats, Peter S; Hirsch, Joshua A

    2015-01-01

    The sacroiliac joint is well known as a cause of low back and lower extremity pain. Prevalence estimates are 10% to 25% in patients with persistent axial low back pain without disc herniation, discogenic pain, or radiculitis based on multiple diagnostic studies and systematic reviews. However, at present there are no definitive management options for treating sacroiliac joint pain. To evaluate the diagnostic accuracy and therapeutic effectiveness of sacroiliac joint interventions. A systematic review of the diagnostic accuracy and therapeutic effectiveness of sacroiliac joint interventions. The available literature on diagnostic and therapeutic sacroiliac joint interventions was reviewed. The quality assessment criteria utilized were the Quality Appraisal of Reliability Studies (QAREL) checklist for diagnostic accuracy studies, Cochrane review criteria to assess sources of risk of bias, and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment (IPM-QRB) criteria for randomized therapeutic trials and Interventional Pain Management Techniques-Quality Appraisal of Reliability and Risk of Bias Assessment for Nonrandomized Studies (IPM-QRBNR) for observational therapeutic assessments. The level of evidence was based on a best evidence synthesis with modified grading of qualitative evidence from Level I to Level V. Data sources included relevant literature published from 1966 through March 2015 that were identified through searches of PubMed and EMBASE, manual searches of the bibliographies of known primary and review articles, and all other sources. For the diagnostic accuracy assessment, and for the therapeutic modalities, the primary outcome measure of pain relief and improvement in functional status were utilized. A total of 11 diagnostic accuracy studies and 14 therapeutic studies were included. The evidence for diagnostic accuracy is Level II for dual diagnostic blocks with at least 70% pain relief as the criterion

  14. Survey methods for assessing land cover map accuracy

    USGS Publications Warehouse

    Nusser, S.M.; Klaas, E.E.

    2003-01-01

    The increasing availability of digital photographic materials has fueled efforts by agencies and organizations to generate land cover maps for states, regions, and the United States as a whole. Regardless of the information sources and classification methods used, land cover maps are subject to numerous sources of error. In order to understand the quality of the information contained in these maps, it is desirable to generate statistically valid estimates of accuracy rates describing misclassification errors. We explored a full sample survey framework for creating accuracy assessment study designs that balance statistical and operational considerations in relation to study objectives for a regional assessment of GAP land cover maps. We focused not only on appropriate sample designs and estimation approaches, but on aspects of the data collection process, such as gaining cooperation of land owners and using pixel clusters as an observation unit. The approach was tested in a pilot study to assess the accuracy of Iowa GAP land cover maps. A stratified two-stage cluster sampling design addressed sample size requirements for land covers and the need for geographic spread while minimizing operational effort. Recruitment methods used for private land owners yielded high response rates, minimizing a source of nonresponse error. Collecting data for a 9-pixel cluster centered on the sampled pixel was simple to implement, and provided better information on rarer vegetation classes as well as substantial gains in precision relative to observing data at a single-pixel.

  15. Task Speed and Accuracy Decrease When Multitasking

    ERIC Educational Resources Information Center

    Lin, Lin; Cockerham, Deborah; Chang, Zhengsi; Natividad, Gloria

    2016-01-01

    As new technologies increase the opportunities for multitasking, the need to understand human capacities for multitasking continues to grow stronger. Is multitasking helping us to be more efficient? This study investigated the multitasking abilities of 168 participants, ages 6-72, by measuring their task accuracy and completion time when they…

  16. Accuracy of activPAL Self-Attachment Methods

    ERIC Educational Resources Information Center

    Kringen, Nina L.; Healy, Genevieve N.; Winkler, Elisabeth A. H.; Clark, Bronwyn K.

    2016-01-01

    This study examined the accuracy of self-attachment of the activPAL activity monitor. A convenience sample of 50 participants self-attached the monitor after being presented with written material only (WMO) and then written and video (WV) instructions; and completed a questionnaire regarding the acceptability of the instructional methods.…

  17. Accuracy and speed feedback: Global and local effects on strategy use

    PubMed Central

    Touron, Dayna R.; Hertzog, Christopher

    2013-01-01

    Background Skill acquisition often involves a shift from an effortful algorithm-based strategy to more fluent memory-based performance. Older adults’ slower strategy transitions can be ascribed to both slowed learning and metacognitive factors. Experimenters often provide feedback on response accuracy; this emphasis may either inadvertently reinforce older adults’ conservatism or might highlight that retrieval is generally quite accurate. RT feedback can lead to more rapid shift to retrieval (Hertzog, Touron, & Hines, 2007). Methods This study parametrically varied trial-by-trial feedback to examine whether strategy shifts in the noun-pair task in younger (M = 19) and older adults (M = 67) were influenced by type of performance feedback: none, trial accuracy, trial RT, or both accuracy and RT. Results Older adults who received accuracy feedback retrieved more often, particularly on difficult rearranged trials, and participants who receive speed feedback performed the scanning strategy more quickly. Age differences were also obtained in local (trial-level) reactivity to task performance, but these were not affected by feedback. Conclusions Accuracy and speed feedback had distinct global (general) influences on task strategies and performance. In particular, it appears that the standard practice of providing trial-by-trial accuracy feedback might facilitate older adults’ use of retrieval strategies in skill acquisition tasks. PMID:24785594

  18. Piezoresistive position microsensors with ppm-accuracy

    NASA Astrophysics Data System (ADS)

    Stavrov, Vladimir; Shulev, Assen; Stavreva, Galina; Todorov, Vencislav

    2015-05-01

    In this article, the relation between position accuracy and the number of simultaneously measured values, such as coordinates, has been analyzed. Based on this, a conceptual layout of MEMS devices (microsensors) for multidimensional position monitoring comprising a single anchored and a single actuated part has been developed. Both parts are connected with a plurality of micromechanical flexures, and each flexure includes position detecting cantilevers. Microsensors having detecting cantilevers oriented in X and Y direction have been designed and prototyped. Experimentally measured results at characterization of 1D, 2D and 3D position microsensors are reported as well. Exploiting different flexure layouts, a travel range between 50μm and 1.8mm and sensors' sensitivity in the range between 30μV/μm and 5mV/μm@ 1V DC supply voltage have been demonstrated. A method for accurate calculation of all three Cartesian coordinates, based on measurement of at least three microsensors' signals has also been described. The analyses of experimental results prove the capability of position monitoring with ppm-(part per million) accuracy. The technology for fabrication of MEMS devices with sidewall embedded piezoresistors removes restrictions in strong improvement of their usability for position sensing with a high accuracy. The present study is, also a part of a common strategy for developing a novel MEMS-based platform for simultaneous accurate measurement of various physical values when they are transduced to a change of position.

  19. Accuracy of physical examination for chronic lumbar radiculopathy

    PubMed Central

    2013-01-01

    Background Clinical examination of patients with chronic lumbar radiculopathy aims to clarify whether there is nerve root impingement. The aims of this study were to investigate the association between findings at clinical examination and nerve root impingement, to evaluate the accuracy of clinical index tests in a specialised care setting, and to see whether imaging clarifies the cause of chronic radicular pain. Methods A total of 116 patients referred with symptoms of lumbar radiculopathy lasting more than 12 weeks and at least one positive index test were included. The tests were the straight leg raising test, and tests for motor muscle strength, dermatome sensory loss, and reflex impairment. Magnetic resonance imaging (n = 109) or computer tomography (n = 7) were imaging reference standards. Images were analysed at the level of single nerve root(s), and nerve root impingement was classified as present or absent. Sensitivities, specificities, and positive and negative likelihood ratios (LR) for detection of nerve root impingement were calculated for each individual index test. An overall clinical evaluation, concluding on the level and side of the radiculopathy, was performed. Results The prevalence of disc herniation was 77.8%. The diagnostic accuracy of individual index tests was low with no tests reaching positive LR >4.0 or negative LR <0.4. The overall clinical evaluation was slightly more accurate, with a positive LR of 6.28 (95% CI 1.06–37.21) for L4, 1.74 (95% CI 1.04–2.93) for L5, and 1.29 (95% CI 0.97–1.72) for S1 nerve root impingement. An overall clinical evaluation, concluding on the level and side of the radiculopathy was also performed, and receiver operating characteristic (ROC) analysis with area under the curve (AUC) calculation for diagnostic accuracy of this evaluation was performed. Conclusions The accuracy of individual clinical index tests used to predict imaging findings of nerve root impingement in patients with chronic lumbar

  20. Accuracy Rates of Ancestry Estimation by Forensic Anthropologists Using Identified Forensic Cases.

    PubMed

    Thomas, Richard M; Parks, Connie L; Richard, Adam H

    2017-07-01

    A common task in forensic anthropology involves the estimation of the ancestry of a decedent by comparing their skeletal morphology and measurements to skeletons of individuals from known geographic groups. However, the accuracy rates of ancestry estimation methods in actual forensic casework have rarely been studied. This article uses 99 forensic cases with identified skeletal remains to develop accuracy rates for ancestry estimations conducted by forensic anthropologists. The overall rate of correct ancestry estimation from these cases is 90.9%, which is comparable to most research-derived rates and those reported by individual practitioners. Statistical tests showed no significant difference in accuracy rates depending on examiner education level or on the estimated or identified ancestry. More recent cases showed a significantly higher accuracy rate. The incorporation of metric analyses into the ancestry estimate in these cases led to a higher accuracy rate. © 2017 American Academy of Forensic Sciences.