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Operating Characteristic (operating + characteristic)
Kinds of Operating Characteristic Terms modified by Operating Characteristic Selected AbstractsJuvenile sex offenders and institutional misconduct: the role of thought psychopathologyCRIMINAL BEHAVIOUR AND MENTAL HEALTH, Issue 5 2008Matt Delisi Background,Little is known about the institutional behaviour of incarcerated sex offenders. Aim,To study the relationships between juvenile sex offending, thought psychopathology and institutional misconduct. Method,We applied negative binomial regression and Area Under Curve Receiver Operating Characteristic (AUC-ROC) analyses to self-report and records data from institutionalised delinquents (N = 813) committed to the California Youth Authority to explore the links between sex offending and institutional misconduct, controlling for offender demographics, institution, index offence, and self-reported and official criminal history. Results,Juvenile sex offending was associated with six forms of institutional misconduct (sexual, general and total misconduct as reviewed by parole board) over 12 and 24 months prior to rating. Two measures of thought psychopathology, which were related to psychosis-like thought, were significantly associated with juvenile sex offender status. These constructs did not, however, mediate the independent predictive effects of adolescent sex offending on institutional misconduct. Conclusion,Interventions to help incarcerated young offenders are likely to be particularly important for those with a sex offending history as they are otherwise likely to persist with antisocial behaviours of all kinds within and beyond the institution. Attention to their thought processes may be particularly useful. Copyright © 2008 John Wiley & Sons, Ltd. [source] Depression in dementia: a comparative and validation study of four brief scales in the elderly ChineseINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 5 2004Chee Kum Lam Abstract Aim The study aimed to determine: (i) the diagnostic accuracy of four brief depression scales, the Geriatric Depression Scale (GDS), Even Briefer Assessment Scale for Depression (EBAS DEP), Single Question and Cornell Scale for Depression in Dementia (Cornell) in an elderly Chinese population with varying dementia severity; and (ii) which scale had the best diagnostic performance. Method All four scales were administered to 88 elderly outpatients with dementia: 66 without and 22 with depression. Receiver Operating Characteristic (ROC) analysis was used to establish the optimal cut-off scores of the GDS, EBAS DEP and Cornell scales. The patients' dementia-severity was dichotomously categorized into mild and moderate-severe dementia, and the above analysis was repeated in both these groups to look at changes in the scales' diagnostic performance as dementia advances. Results The best diagnostic scale for detecting depression in dementia was the Cornell scale. Its optimal cut-off score was 6/7 (sensitivity 91.7%, specificity 80.0%) in the mild dementia group and 12/13 (sensitivity 70.0%, specificity 87.0%) in the more advanced dementia group. The optimal cut-off scores of the GDS and EBAS DEP also shifted to higher values when moving from the mild to the more advanced dementia groups, indicating the increasing difficulty on all these scales to detect depression with worsening cognitive impairment. The Single Question, however, was more robust with much less changes in its diagnostic parameters in both dementia cohorts: sensitivity 58.3%, specificity 90.0% for mild dementia, and 60.0 and 84.8%, respectively, for more advanced dementia. Conclusion An efficient strategy to diagnose depression in dementia amongst elderly Chinese patients is to administer the Single Question followed by, when necessary, the Cornell scale. Copyright © 2004 John Wiley & Sons, Ltd. [source] Lymphocyte volume and conductivity indices of the haematology analyser Coulter® GEN.STM in lymphoproliferative disorders and viral diseasesINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 1 2006M. SILVA Summary The haematology analyser Coulter® GEN.STM gives a set of data ,,positional parameters', defining white blood cell (WBC) populations by mean of index values (mean and standard deviation of volume, conductivity and scatter, used to identify the WBC populations). The volume and conductivity parameters related to the lymphocytes were analysed at diagnosis in patients suffering from chronic B-lymphocytic leukaemia (B-CLL), other non-CLL lymphoproliferative disorders (OLPD) and viral diseases. The standard deviation of volume index (SDVI) is significantly higher in the three groups, whereas the mean volume index (MVI) is significantly lower in B-CLL, and increased in OLPD and viral diseases. These two groups could be distinguished by their mean conductivity index (MCI), which is significantly lower in viral disease group. Cut-offs were calculated for each parameter by the mean of Receiver Operating Characteristic (ROC) analysis. The study of the detection performances showed that the combination of lymphocyte count with SDVI, MVI and MCI could be used with a good sensitivity and specificity to discriminate between the most frequent lymphocyte pathologies, even in patients with normal lymphocyte count. [source] Evaluating screening questionnaires using receiver Operating Characteristic (ROC) curves from two-phase (double) samplesINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 3 2000Giulia Bisoffi Abstract The characteristics of psychiatric screening tests (for example, sensitivity, specificity, and AUC , the area under an ROC curve) are frequently assessed using data arising from two-phase samples. Too often, however, the statistical methods that are used are incorrect. They do not appropriately account for the sampling design. Valid methods for the estimate of sensitivity, specificity and, in particular, the AUC, together with its standard error, are discussed in detail and a Stata macro for the implementation of these methods is provided. Simple weighting procedures are used to correct for verification biases arising from the two-phase design, together with bootstrap or jackknife sampling for the calculation of valid standard errors. Copyright © 2000 Whurr Publishers Ltd. [source] Detecting Alcohol-Related Problems in Developing Countries: A Comparison of 2 Screening Measures in IndiaALCOHOLISM, Issue 12 2009Madhabika B. Nayak Background:, There is inadequate recognition of alcohol misuse as a public health issue in India. Information on screening measures is critical for prevention and early intervention efforts. This study critically evaluated the full and shorter versions of the AUDIT and RAPS4-QF as screening measures for alcohol use disorders (AUDs) in a community sample of male drinkers in Goa, India. Methods:, Data from male drinking respondents in a population study on alcohol use patterns and sexual risk behaviors in randomly selected rural and urban areas of North Goa are reported. Overall, 39% (n = 743) of the 1899 screened men, age 18 to 49, reported consuming alcohol in the last 12 months. These current drinkers were administered the screening measures as part of detailed interviews on drinking patterns and AUD symptoms. Receiver Operating Characteristic (ROC) analysis was conducted for each combination of screening measure and criterion (alcohol dependence or any AUD). Reliability and correlations among the 4 measures were also examined. Results:, All 4 measures performed well with area under the curves of at least 0.79. The full screeners that included both drinking patterns and problem items (the AUDIT and the RAP4-QF) performed better than their shorter versions (the AUDIT-C and the RAPS4) in detecting AUDs. Performance of the AUDIT and RAPS4-QF improved with lowered and raised thresholds, respectively, and alternate cut-off scores are suggested. Scores on the full measures were significantly correlated (0.80). Reliability estimates for the AUDIT measures were higher than those for the RAPS4 measures. Conclusions:, All measures were efficient at detecting AUDs. When screening for alcohol-related problems among males in the general population in India, cut-off scores for screeners may need to be adjusted. Selecting an appropriate screening measure and cut-off score necessitates careful consideration of the screening context and resources available to confirm alcohol-related diagnoses. [source] A general class of hierarchical ordinal regression models with applications to correlated roc analysisTHE CANADIAN JOURNAL OF STATISTICS, Issue 4 2000Hemant Ishwaran Abstract The authors discuss a general class of hierarchical ordinal regression models that includes both location and scale parameters, allows link functions to be selected adaptively as finite mixtures of normal cumulative distribution functions, and incorporates flexible correlation structures for the latent scale variables. Exploiting the well-known correspondence between ordinal regression models and parametric ROC (Receiver Operating Characteristic) curves makes it possible to use a hierarchical ROC (HROC) analysis to study multilevel clustered data in diagnostic imaging studies. The authors present a Bayesian approach to model fitting using Markov chain Monte Carlo methods and discuss HROC applications to the analysis of data from two diagnostic radiology studies involving multiple interpreters. RÉSUMÉ Les auteurs s'intéressent à une classe assez vaste de modèles de régression ordinale avec paramètres de localisation et d'échelle, laquelle permet la sélection adaptative de fonctions de lien s'exprimant comme mélanges finis de fonctions de répartition normales et fournit des structures de correlation flexibles pour les variables d'échelle latentes. En exploitant la correspondance bien connue entre les modèles de régression ordinale et les courbes d'efficacité paramétriques (CEP) des tests diagnostiques, il est possible d'analyser des données d'imagerie médicate diagnostique regroupées à plusieurs niveaux au moyen d'une CEP hiéiarchique. Les auteurs décrivent une approche bayésienne pour l'ajustement de tels modèles au moyen des méthodes de Monte Carlo à cha,ne de Markov et présentent deux applications concrètes concernant l'interprétation de clichés radiologiques [source] Limited-area ensemble predictions at the Norwegian Meteorological InstituteTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 621 2006Inger-Lise Frogner Abstract This study aims at improving 0,3 day probabilistic forecasts of precipitation events in Norway. For this purpose a limited-area ensemble prediction system (LAMEPS) is tested. The horizontal resolution of LAMEPS is 28 km, and there are 31 levels in the vertical. The state variables provided as initial and lateral boundary conditions for the limited-area forecasts are perturbed using a dedicated version of the European Centre for Medium-Range Weather Forecasts (ECMWF) global ensemble prediction system, TEPS. These are constructed by combining initial and evolved singular vectors that at final time (48 h) are targeted to maximize the total energy in a domain containing northern Europe and adjacent sea areas. The resolution of TEPS is T255 with 40 levels. The test period includes 45 cases with 21 ensemble members in each case. We focus on 24 h accumulated precipitation rates with special emphasis on intense events. We also investigate a combination of TEPS and LAMEPS resulting in a system (NORLAMEPS) with 42 ensemble members. NORLAMEPS is compared with the 21-member LAMEPS and TEPS as well as the regular 51-member EPS run at ECMWF. The benefit of using targeted singular vectors is seen by comparing the 21-member TEPS with the 51-member operational EPS, as TEPS has considerably larger spread between ensemble members. For other measures, such as Brier Skill Score (BSS) and Relative Operating Characteristic (ROC) curves, the scores of the two systems are for most cases comparable, despite the difference in ensemble size. NORLAMEPS has the largest ensemble spread of all four ensemble systems studied in this paper, while EPS has the smallest spread. Nevertheless, EPS has higher BSS with NORLAMEPS approaching for the highest precipitation thresholds. For the area under the ROC curve, NORLAMEPS is comparable with or better than EPS for medium to large thresholds. Copyright © 2006 Royal Meteorological Society [source] High-resolution limited-area ensemble predictions based on low-resolution targeted singular vectorsTHE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 582 2002Inger-Lise Frogner Abstract The operational limited-area model, HIRLAM, at the Norwegian Meteorological Institute is used at 0.25° latitude/longitude resolution for ensemble weather prediction over Northern Europe and adjacent parts of the North Atlantic Ocean; this system is called LAMEPS. Initial and lateral boundary perturbations are taken from coarse-resolution European Centre for Medium-Range Weather Forecasts global ensemble members based on targeted singular vectors (TEPS). Five winter and five summer cases in 1997 consisting of 20 ensemble members plus one control forecast are integrated. Two sets of ensembles are generated, one for which both initial and lateral boundary conditions are perturbed, and another with only the initial fields perturbed. The LAMEPS results are compared to those of TEPS using the following measures: r.m.s. ensemble spread of 500 hPa geopotential height; r.m.s. ensemble spread of mean-sea-level pressure; Brier Skill Scores (BSS); Relative Operating Characteristic (ROC) curves; and cost/loss analyses. For forecasts longer than 12 hours, all measures show that perturbing the boundary fields is crucial for the performance of LAMEPS. For the winter cases TEPS has slightly larger ensemble spread than LAMEPS, but this is reversed for the summer cases. Results from BSS, ROC and cost/loss analyses show that LAMEPS performed considerably better than TEPS for precipitation, a result that is promising for forecasting extreme precipitation amounts. We believe this result to be linked to the high predictability of mesoscale flows controlled by complex topography. For two-metre temperature, however, TEPS frequently performed better than LAMEPS. Copyright © 2002 Royal Meteorological Society [source] Using the Optimal Robust Receiver Operating Characteristic (ROC) Curve for Predictive Genetic TestsBIOMETRICS, Issue 2 2010Qing Lu Summary Current ongoing genome-wide association (GWA) studies represent a powerful approach to uncover common unknown genetic variants causing common complex diseases. The discovery of these genetic variants offers an important opportunity for early disease prediction, prevention, and individualized treatment. We describe here a method of combining multiple genetic variants for early disease prediction, based on the optimality theory of the likelihood ratio (LR). Such theory simply shows that the receiver operating characteristic (ROC) curve based on the LR has maximum performance at each cutoff point and that the area under the ROC curve so obtained is highest among that of all approaches. Through simulations and a real data application, we compared it with the commonly used logistic regression and classification tree approaches. The three approaches show similar performance if we know the underlying disease model. However, for most common diseases we have little prior knowledge of the disease model and in this situation the new method has an advantage over logistic regression and classification tree approaches. We applied the new method to the type 1 diabetes GWA data from the Wellcome Trust Case Control Consortium. Based on five single nucleotide polymorphisms, the test reaches medium level classification accuracy. With more genetic findings to be discovered in the future, we believe a predictive genetic test for type 1 diabetes can be successfully constructed and eventually implemented for clinical use. [source] Identifying Combinations of Cancer Markers for Further Study as Triggers of Early InterventionBIOMETRICS, Issue 4 2000Stuart G. Baker Summary. In many long-term clinical trials or cohort studies, investigators repeatedly collect and store tissue or serum specimens and later test specimens from cancer cases and a random sample of controls for potential markers for cancer. An important question is what combination, if any, of the molecular markers should be studied in a future trial as a trigger for early intervention. To answer this question, we summarized the performance of various combinations using Receiver Operating Characteristic (ROC) curves, which plot true versus false positive rates. To construct the ROC curves, we proposed a new class of nonparametric algorithms which extends the ROC paradigm to multiple tests. We fit various combinations of markers to a training sample and evaluated the performance in a test sample using a target region based on a utility function. We applied the methodology to the following markers for prostate cancer, the last value of total prostate-specific antigen (PSA), the last ratio of total to free PSA, the last slope of total PSA, and the last slope of the ratio. In the test sample, the ROC curve for last total PSA was slightly closer to the target region than the ROC curve for a combination of four markers. In a separate validation sample, the ROC curve for last total PSA intersected the target region in 77% of bootstrap replications, indicating some promise for further study. We also discussed sample size calculations. [source] INFORMATION POINT: Receiver Operating Characteristics (ROC) curves (see pg.JOURNAL OF CLINICAL NURSING, Issue 1 2002[source] Effect of Normal Saline Infusion on the Diagnostic Utility of Base Deficit in Identifying Major Injury in Trauma PatientsACADEMIC EMERGENCY MEDICINE, Issue 12 2006Richard Sinert DO Abstract Background Base deficit (BD) is a reliable marker of metabolic acidosis and is useful in gauging hemorrhage after trauma. Resuscitation with chloride-rich solutions such as normal saline (NS) can cause a dilutional acidosis, possibly confounding the interpretation of BD. Objectives To test the diagnostic utility of BD in distinguishing minor from major injury after administration of NS. Methods This was a prospective observational study at a Level 1 trauma center. The authors enrolled patients with significant mechanism of injury and measured BD at triage (BD-0) and at four hours after triage (BD-4). Major injury was defined by any of the following: injury severity score of ,15, drop in hematocrit of ,10 points, or the patient requiring a blood transfusion. Patients were divided into a low-volume (NS < 2L) and a high-volume (NS , 2L) group. Data were reported as mean (±SD). Student's t- and Wilcoxon tests were used to compare data. Receiver operating characteristic (ROC) curves tested the utility of BD-4 in differentiating minor from major injury in the study groups. Results Four hundred eighty-nine trauma patients (mean age, 36 [± 18] yr) were enrolled; 82% were male, and 34% had penetrating injury. Major-(20%) compared with minor-(80%) injury patients were significantly (p = 0.0001) more acidotic (BD-0 mean difference: ,3.3 mmol/L; 95% confidence interval [CI] =,2.5 to ,4.2). The high-volume group (n = 174) received 3,342 (±1,821) mL, and the low-volume group (n = 315) received 621 (±509) mL of NS. Areas under the ROC curves for the high-volume (0.63; 95% CI = 0.52 to 0.74) and low-volume (0.73; 95% CI = 0.60 to 0.86) groups were not significantly different from each other. Conclusions Base deficit was able to distinguish minor from major injury after four hours of resuscitation, irrespective of the volume of NS infused. [source] Screening for depression and anxiety disorders in primary care patientsDEPRESSION AND ANXIETY, Issue 7 2007Adomas Bunevicius B.S. Abstract Mood and anxiety disorders are highly prevalent in primary health care. In this study we assessed performance of the Hospital Anxiety and Depression Scale (HADS) for screening of depression and anxiety disorders in a population of primary care patients. A total of 503 primary care patients consecutively admitted to the primary care medical center in Kaunas, Lithuania, completed the study. We found that the HADS subscale of depression (HADS-D) at a cutoff score of 6 or more showed the best performance screening for a major depressive episode diagnosed by means of the Mini International Neuropsychiatric Interview (MINI), with a sensitivity of 80%, specificity of 69%, positive predictive value of 80%, negative predictive value of 92%, and area under the receiver operating characteristic (ROC) curve of 0.75. Performance of the HADS-D against MINI diagnosis of dysthymia was weak. The HADS subscale of anxiety (HADS-A) at a cutoff score of 9 or more showed the best performance screening for MINI diagnosis of overall anxiety disorders, with a sensitivity of 77%, specificity of 75%, positive predictive value of 53%, negative predictive value of 90%, and area under the ROC curve of 0.76. These results suggest that in primary care patients HADS is an adequate screening instrument for the MINI diagnoses of major depressive episode, but not for dysthymia at a cutoff score of 6, and for anxiety disorders at a cutoff score of 9. Depression and Anxiety 24:455,460, 2007. © 2006 Wiley-Liss, Inc. [source] High-end specificity of the children's depression inventory in a sample of anxiety-disordered youthDEPRESSION AND ANXIETY, Issue 1 2005Jonathan S. Comer M.A. Abstract Using a receiver operating characteristic (ROC) analysis, the present study investigated the ability of the Children's Depression Inventory (CDI) to correctly detect depression in a sample of treatment-seeking anxious youth (N=44). The ADIS-C/P was used to determine diagnostic status of participants. Anxious children who met diagnostic criteria for a depressive disorder scored higher on the CDI than anxious children who did not meet criteria for a depressive disorder, supporting the CDI as a continuous measure of depressive symptomatology. In contrast, with regard to detecting a depressive disorder, CDI cut scores did not achieve favorable values across diagnostic utility indices (including the cut score of 13 that has been recommended). These findings support the CDI as a continuous measure of depressive symptoms, but do not support the CDI as a sole assessment for a diagnosis of depression within a sample of anxiety-disordered youth. Depression and Anxiety 22:11,19, 2005. © 2005 Wiley-Liss, Inc. [source] Detecting language problems: accuracy of five language screening instruments in preschool childrenDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 2 2007H M E Van Agt MA To identify a simple and effective screening instrument for language delays in 3-year-old children the reliability, validity, and accuracy of five screening instruments were examined. A postal questionnaire sent to parents of 11423 children included the Dutch version of the General Language Screen (GLS), the Van Wiechen (VW) items, the Language Screening Instrument for 3- to 4-year-olds, consisting of a parent form (LSI-PF) and a child test (LSI-CT), and parents' own judgement of their child's language development on a visual analogue scale (VAS). The response rate was 78% or 8877 children. Reliability (internal consistency) was found to be acceptable (,=0.67,0.72) for all instruments. Significant correlations between the screening instruments (r=0.29,0.55, p<0.01) indicated good concurrent validity. Accuracy was estimated by the sensitivity, specificity, and receiver operating characteristic (ROC) curves against two reference tests based on parent report and specialists' judgement. If the test would classify approximately 5% of the population as screen-positive, the mean sensitivity was 50%; assigning between 20% and 30% of the population as screen-positive, the mean sensitivity was 77%. The sensitivity was lowest for the LSI-CT (range 43,62%), whereas short instruments like the LSI-PF, VW, and the one-item VAS exhibited high levels of sensitivity (range 50,86%). The area under the ROC curves, ranged from 0.75 to 0.87. Apparently, short and simple parent report instruments like the LSI-PF and the one-item VAS perform remarkably well in detecting language delays in preschool children. [source] Should liver function tests be included in definitions of metabolic syndrome?DIABETIC MEDICINE, Issue 5 2008Evidence from the association between liver function tests, components of metabolic syndrome, prevalent cardiovascular disease Abstract Aims The definition of metabolic syndrome (MS) continues to be debated and does not include abnormal liver function tests (LFTs). This study aims to determine: (1) the association between the five ATP3 MS diagnostic components and different LFTs, and (2) the association between raised LFTs and prevalent cardiovascular disease (CVD). Methods A total of 1357 patients, without alcoholism or known liver disease, from randomly selected households from rural Victoria, Australia, attended for biomedical assessment. Receiver operating characteristic (ROC) areas under the curve (AUC) were determined for associations between the ATP3 diagnostic components, and between LFTs and ATP3 diagnostic components. Results The range of ROC AUC for ATP3 diagnostic components was 0.60,0.77. Waist had the strongest association and blood pressure the weakest. The strength of association between ATP3 diagnostic components and gamma GT (GGT) was similar (0.63,0.72), but was less for alanine transaminase and aspartate transaminase. Using the ROC-derived GGT cut-off (men 27 IU, women 20 IU), those with MS and a high GGT had more CVD than those with MS and a low GGT, and those without MS (18% vs. 10% vs. 7%, respectively; P < 0.001). Among those with MS, after adjusting for covariates, the odds ratio of CVD was 2.66 (1.18,5.96) for a high GGT compared to a low GGT. CVD was not significantly more prevalent in MS patients with a low GGT compared to non-MS patients. Conclusions We suggest that including a raised GGT in the criteria for MS could increase its predictive nature for CVD. Prospective studies are needed to confirm this finding. [source] ,Numbness of the feet' is a poor indicator for polyneuropathy in Type 2 diabetic patientsDIABETIC MEDICINE, Issue 2 2000L. V. Franse Summary Aims To identify neuropathic sensory symptoms associated with a clinical neurological examination (CNE) and to investigate whether these symptoms could be used as a diagnostic or screening tool for diabetic polyneuropathy in general practice. Methods Five hundred and eighty-eight patients with Type 2 diabetes, recruited from 26 general practices in the Netherlands, underwent a CNE and completed a diabetes symptom checklist that included 10 items on neuropathic sensory symptoms. Linear regression analyses were performed to assess the association between neuropathic symptoms and CNE. Receiver operating characteristic (ROC) curves were created to assess the diagnostic properties of neuropathic symptoms. Results In this population, with a mean age of 66.8 years, 32% were identified with diabetic polyneuropathy according to the CNE. Variables that showed the strongest association with CNE score were age (, = 0.41), symptoms of sensory alteration (, = 0.27), and the item ,numbness of the feet' (, = 0.35) in particular. ROC curves showed that prediction of diabetic polyneuropathy from these symptoms was unsatisfying. The sensitivity and specificity of daily symptoms of ,numbness of the feet' were 28% and 93%, respectively, in patients <,68 years, and 22% and 92%, respectively, in patients ,,68 years. Conclusions Identification of neuropathic sensory symptoms is not useful as a diagnostic or even a screening tool in the assessment of diabetic neuropathy in daily practice. Therefore, the results reported in this paper mandate an annual foot examination by the general practitioner. [source] The Cannabis Use Problems Identification Test (CUPIT): development, reliability, concurrent and predictive validity among adolescents and adultsADDICTION, Issue 4 2010Jan Bashford ABSTRACT Aims To describe the empirical construction and initial validation of the Cannabis Use Problems Identification Test (CUPIT), a brief self-report screening instrument for detection of currently and potentially problematic cannabis use. Design In a three-phase prospective design an item pool of candidate questions was generated from a literature review and extensive expert consultation. The CUPIT internal structure, cross-sectional and longitudinal psychometric properties were then systematically tested among heterogeneous past-year users. Participants Volunteer participants were 212 high-risk adolescents (n = 138) and adults (n = 74) aged 13,61 years from multiple community settings. Measurements The comprehensive assessment battery included several established measures of cannabis-related pathology for CUPIT validation, with DSM-IV/ICD-10 diagnoses of cannabis use disorders as criterion standard. Findings Sixteen items loading highly on two subscales derived from principal components analysis exhibited good to excellent test,retest (0.89,0.99) and internal consistency reliability (0.92, 0.83), and highly significant ability to discriminate diagnostic subgroups along the severity continuum (non-problematic, risky, problematic use). Twelve months later, baseline CUPIT scores demonstrated highly significant longitudinal predictive utility for respondents' follow-up diagnostic group membership. Receiver operating characteristic (ROC) analysis identified a CUPIT score of 12 to be the optimal cut-point for maximizing sensitivity for both currently diagnosable cannabis use disorder and those at risk of meeting diagnostic criteria in the following 12 months. Conclusions The CUPIT is a brief cannabis screener that is reliable, valid and acceptable for use across diverse community settings and consumers of all ages. The CUPIT has clear potential to assist with achievement of public health goals to reduce cannabis-related harms in the community. [source] Validation of the alcohol, smoking and substance involvement screening test (ASSIST)ADDICTION, Issue 6 2008Rachel Humeniuk ABSTRACT Aim The concurrent, construct and discriminative validity of the World Health Organization's Alcohol, Smoking and Substance Involvement Screening Test (ASSIST) were examined in a multi-site international study. Participants One thousand and 47 participants, recruited from drug treatment (n = 350) and primary health care (PHC) settings (n = 697), were administered a battery of instruments. Measurements Measures included the ASSIST; the Addiction Severity Index-Lite (ASI-Lite); the Severity of Dependence Scale (SDS); the MINI International Neuropsychiatric Interview (MINI-Plus); the Rating of Injection Site Condition (RISC); the Drug Abuse Screening Test (DAST); the Alcohol Use Disorders Identification Test (AUDIT); the Revised Fagerstrom Tolerance Questionnaire (RTQ); and the Maudsley Addiction Profile (MAP). Findings Concurrent validity was demonstrated by significant correlations between ASSIST scores and scores from the ASI-Lite (r = 0.76,0.88), SDS (r = 0.59), AUDIT (r = 0.82) and RTQ (r = 0.78); and significantly greater ASSIST scores for those with MINI-Plus diagnoses of abuse or dependence (P < 0.001). Construct validity was established by significant correlations between ASSIST scores and measures of risk factors for the development of drug and alcohol problems (r = 0.48,0.76). Discriminative validity was established by the capacity of the ASSIST to discriminate between substance use, abuse and dependence. Receiver operating characteristic (ROC) analysis was used to establish cut-off scores with suitable specificities (50,96%) and sensitivities (54,97%) for most substances. Conclusions The findings demonstrated that the ASSIST is a valid screening test for identifying psychoactive substance use in individuals who use a number of substances and have varying degrees of substance use. [source] Use of advanced red blood cell and reticulocyte indices improves the accuracy in diagnosing iron deficiency in pregnant women at termEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 6 2007Mari Ervasti Abstract Objectives:, Detection of iron deficiency during pregnancy with hemoglobin (Hb) and serum measurements is insignificant as the measurements may be affected by e.g. hemodilution or accelerated erythropoiesis. This study tests whether cell indices will give a more reliable measure of iron deficiency in pregnant women at term. Methods:, The population was 202 pregnant women. Using the ADVIA 120 hematology system, Hb, mean cell volume (MCV), percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr), and cellular hemoglobin in reticulocytes (CHr) were tested. Additionally, transferrin saturation (TfSat), ferritin, and transferrin receptor (TfR) were analyzed. Receiver operating characteristic (ROC) curves and area under the ROC curves (AUC) were used as statistical methods. Results:, When TfSat (,11%) was used as the reference test for iron deficiency, %HYPOm and CHr had a sensitivity of 58.1% and 80.7%, while the specificities were 82.6% and 71.3%, respectively. Additionally, the AUC values were %HYPOr 0.80, CHr 0.79, ferritin 0.77, %HYPOm 0.75, TfR 0.67, MCV 0.63 and Hb 0.64. The results provided by the cell indices alone (%HYPOm or CHr) were in good agreement with the results based on the usage of a combination of three commonly used tests (Hb, MCV, ferritin). Conclusions:, This study suggests that the most practical way to diagnose iron deficiency in pregnant women at term is to use cell indices such as CHr and %HYPOm provided by the automated hematological analyzer. Further studies are needed to determine the usefulness of the cell indices in diagnosing iron deficiency longitudinally during the course of pregnancy. [source] Electrophysiological sensory demyelination in typical chronic inflammatory demyelinating polyneuropathyEUROPEAN JOURNAL OF NEUROLOGY, Issue 7 2010Y. A. Rajabally Background:, The presence of electrophysiological demyelination of sensory nerves is not routinely assessed in the evaluation of suspected chronic inflammatory demyelinating polyneuropathy (CIDP). Whether this can be useful is unknown. Methods:, We compared, using surface recording techniques, in 19 patients with typical CIDP and 26 controls with distal large fibre sensory axonal neuropathy, the forearm median sensory conductions, sensory nerve action potential (SNAP) amplitudes and durations and sensory nerve conduction velocities (SNCVs) of median, radial and sural nerves. Results:, Median nerve sensory conduction block (SCB) across the forearm was greater in CIDP patients than in controls (P = 0.005). SNAP durations were longer in CIDP patients for median (P = 0.001) and sural nerves (P = 0.004). Receiver operating characteristic (ROC) curves provided sensitive (>40%) and specific (>95%) cut-offs for median nerve SCB as well as median and sural SNAP durations. SNCVs were significantly slower for median and sural nerves in CIDP patients, but ROC curves did not demonstrate cut-offs with useful sensitivities/specificities. Median SCB or prolonged median SNAP duration or prolonged sural SNAP duration offered a sensitivity of 73.7% for CIDP and specificity of 96.2%. Used as additional parameters, they improved diagnostic sensitivity of the American Academy of Neurology (AAN) criteria for CIDP of 1991, from 42.1% to 78.9% in this population, with preserved specificity of 100%. Discussion:, Sensory electrophysiological demyelination is present and may be diagnostically useful in typical CIDP. SCB detection and SNAP duration prolongation appear to represent more useful markers of demyelination than SNCV reduction. [source] Detection of marginal defects of composite restorations with conventional and digital radiographsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 4 2002Rainer Haak The purpose of this study was to determine the validity of detecting approximal imperfections of composite fillings using three intraoral radiographic systems in vitro. Class II composite resin restorations (108) with three radiopacities (264, 306, 443% Al 99.5) of which 27 had marginal openings or overhangs, respectively, were conventionally (Ektaspeed plus) and digitally (Dexis, Digora) radiographed. Images were assessed by 10 observers for the presence of marginal gaps and overhangs, as well as for their need of restorative treatment according to a five-point confidence rating scale. The validity of the observations were expressed as areas under receiver operating characteristic (ROC) curves (Aroc). Repeated measures analysis of variance revealed significant effects of ,radiographic system' and ,diagnostic purpose'. Marginal overhangs (Aroc = 0.90) were significantly easier to diagnose than openings (Aroc = 0.63). Marginal gaps were better detected on conventional and Dexis radiographs than on Digora images. the range of sensitivities and specificities of the treatment decision was 0.53,0.56 and 0.87,0.88, respectively. It was concluded that the validity of detecting marginal defects of composite resin restorations based on radiographs was only slightly affected by the radiographic system being used. The diagnosis of marginal gaps frequently resulted in false-positive and false-negative decisions. [source] Detection of artificially induced vertical radicular fractures using Tuned Aperture Computed TomographyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2001Madhu K. Nair This study compared the accuracy of three imaging modalities for the detection of artificially induced vertical root fractures (VRF) on teeth in cadaver mandibles. Fifty-four single-rooted, endodontically treated mandibular teeth being prepared to carry posts were evaluated using direct digital radiography (DDI) with a Schick sensor, unprocessed Tuned Aperture Computed Tomography® (TACT-U) images and iteratively restored TACT (TACT-IR) images. Twenty-eight of these teeth had been subjected to fracture induction using an apically driven force. Nine basis images were used for each TACT image generation. Eight observers used a five-point confidence rating scale to record the confidence with which they considered a fracture to be present or not. Sensitivity and specificity values were computed and receiver operating characteristic (ROC) curves were generated. The areas under the curves (Az) used as an indication of the diagnostic accuracy of the imaging system were as follows: DDI: 0.37; TACT-U: 0.77 and TACT-IR: 0.81. DDI was significantly inferior to the TACT modalities. Differences in detection efficacy based on observers and observation sessions were noted on ANOVA and post-hoc Tukey's tests. This study indicates that TACT is the imaging modality of choice for VRF in endodontically treated teeth. [source] Imaging of Mandibular Trauma: ROC AnalysisACADEMIC EMERGENCY MEDICINE, Issue 7 2001Dipl., Madhu K. Nair BDS Objectives: To compare the diagnostic efficacies of panoramic radiographs, mandibular trauma series, and digitized radiographs for detection of fractures of the mandible. Methods: Fractures were induced using blunt trauma in 25 cadaver mandibles. Panoramic radiographs, digitized radiographs, and mandibular series comprising an anteroposterior view, two lateral oblique, and a reverse Towne's were used. Six observers recorded their diagnoses using a five-point confidence rating scale. The data were analyzed using receiver operating characteristic (ROC) curve analysis. Results: Significant differences based on imaging modalities were found (p < 0.0015) in the area under the curves (Az): panoramic radiograph, 0.8762; mandibular series, 0.7521; panoramic plus anteroposterior radiographs combination, 0.8886; and digitized mandibular series, 0.7723. No observer-based differences were noted. Condylar and coronoid fractures were difficult to detect than those in other areas of the mandible (p < 0.033). Intra- and inter-observer agreements were high (,w= 0.81 and 0.76, respectively). Conclusions: Panoramic radiographs are adequate for detection of mandibular fractures. Addition of an anteroposterior view augments diagnostic accuracy. [source] Modelling patterned ground distribution in Finnish Lapland: an integration of topographical, ground and remote sensing informationGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2006Jan Hjort Abstract New data technologies and modelling methods have gained more attention in the field of periglacial geomorphology during the last decade. In this paper we present a new modelling approach that integrates topographical, ground and remote sensing information in predictive geomorphological mapping using generalized additive modelling (GAM). First, we explored the roles of different environmental variable groups in determining the occurrence of non-sorted and sorted patterned ground in a fell region of 100 km2 at the resolution of 1 ha in northern Finland. Second, we compared the predictive accuracy of ground-topography- and remote-sensing-based models. The results indicate that non-sorted patterned ground is more common at lower altitudes where the ground moisture and vegetation abundance is relatively high, whereas sorted patterned ground is dominant at higher altitudes with relatively high slope angle and sparse vegetation cover. All modelling results were from good to excellent in model evaluation data using the area under the curve (AUC) values, derived from receiver operating characteristic (ROC) plots. Generally, models built with remotely sensed data were better than ground-topography-based models and combination of all environmental variables improved the predictive ability of the models. This paper confirms the potential utility of remote sensing information for modelling patterned ground distribution in subarctic landscapes. [source] Prospective Validation of a Modified Thrombolysis In Myocardial Infarction Risk Score in Emergency Department Patients With Chest Pain and Possible Acute Coronary SyndromeACADEMIC EMERGENCY MEDICINE, Issue 4 2010Erik P. Hess MD Abstract Objectives:, This study attempted to prospectively validate a modified Thrombolysis In Myocardial Infarction (TIMI) risk score that classifies patients with either ST-segment deviation or cardiac troponin elevation as high risk. The objectives were to determine the ability of the modified score to risk-stratify emergency department (ED) patients with chest pain and to identify patients safe for early discharge. Methods:, This was a prospective cohort study in an urban academic ED over a 9-month period. Patients over 24 years of age with a primary complaint of chest pain were enrolled. On-duty physicians completed standardized data collection forms prior to diagnostic testing. Cardiac troponin T-values of >99th percentile (,0.01 ng/mL) were considered elevated. The primary outcome was acute myocardial infarction (AMI), revascularization, or death within 30 days. The overall diagnostic accuracy of the risk scores was compared by generating receiver operating characteristic (ROC) curves and comparing the area under the curve. The performance of the risk scores at potential decision thresholds was assessed by calculating the sensitivity and specificity at each potential cut-point. Results:, The study enrolled 1,017 patients with the following characteristics: mean (±SD) age 59.3 (±13.8) years, 60.6% male, 17.9% with a history of diabetes, and 22.4% with a history of myocardial infarction. A total of 117 (11.5%) experienced a cardiac event within 30 days (6.6% AMI, 8.9% revascularization, 0.2% death of cardiac or unknown cause). The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy (area under the ROC curve = 0.83 vs. 0.79; p = 0.030; absolute difference 0.037; 95% confidence interval [CI] = 0.004 to 0.071). The specificity of the modified score was lower at all cut-points of >0. Sensitivity and specificity at potential decision thresholds were: >0 = sensitivity 96.6%, specificity 23.7%; >1 = sensitivity 91.5%, specificity 54.2%; and >2 = sensitivity 80.3%, specificity 73.4%. The lowest cut-point (TIMI/modified TIMI >0) was the only cut-point to predict cardiac events with sufficient sensitivity to consider early discharge. The sensitivity and specificity of the modified and original TIMI risk scores at this cut-point were identical. Conclusions:, The modified TIMI risk score outperformed the original with regard to overall diagnostic accuracy. However, it had lower specificity at all cut-points of >0, suggesting suboptimal risk stratification in high-risk patients. It also lacked sufficient sensitivity and specificity to safely guide patient disposition. Both scores are insufficiently sensitive and specific to recommend as the sole means of determining disposition in ED chest pain patients. ACADEMIC EMERGENCY MEDICINE,2010; 17:368,375 © 2010 by the Society for Academic Emergency Medicine [source] Serum Levels of Leptin As Marker For Patients At High Risk of Gastric CancerHELICOBACTER, Issue 6 2009Lisette G. Capelle Abstract Background:, Serological screening for gastric cancer (GC) may reduce mortality. However, optimal serum markers for advanced gastric precursor lesions are lacking. Aim:, To evaluate in a case,control study whether serum leptin levels correlate with intestinal metaplasia (IM) and can serve as a tool to identify patients at high risk for GC. Materials and Methods:, Cases were patients with a previous diagnosis of IM or dysplasia, controls were patients without such a diagnosis. All patients underwent endoscopy. Fasting serum was collected for the measurement of leptin, pepsinogens I/II, gastrin, and Helicobacter pylori. Receiver operating characteristic (ROC) curves and their area under the curve (AUC) were provided to compare serum leptin levels with other serological markers. Results:, One hundred nineteen cases and 98 controls were included. In cases, the median leptin levels were 116.6 pg/mL versus 81.9 pg/mL in controls (p = .01). After adjustment for age, sex and BMI, leptin levels remained higher in cases than in controls (p < .005). In multivariate analysis, male sex (p = .002), age (<0.001), low pepsinogen levels (p = .004) and high leptin levels (p = .04) were independent markers for the presence of IM. In addition, a ROC curve including age, sex and pepsinogen I levels had an AUC of 0.79 (95% CI (0.73,0.85)). Adding serum leptin levels increased the AUC to 0.81 (95% CI (0.75,0.86)). Conclusions:, High leptin levels are associated with an increased risk of IM. Moreover, serum leptin levels are a significant independent marker for the presence of IM. However, in combination with the serological test for pepsinogen I the additional value of serum leptin levels is rather limited. [source] Quantitative determination of the diagnostic accuracy of the synovitis score and its componentsHISTOPATHOLOGY, Issue 3 2010Elisabeth Slansky Slansky E, Li J, Häupl T, Morawietz L, Krenn V & Pessler F (2010) Histopathology,57, 436,443 Quantitative determination of the diagnostic accuracy of the synovitis score and its components Aims:, To assess the diagnostic accuracy of a three-component synovitis score and to determine the relative contribution of each of its components to its overall discriminatory power. Methods and results:, The synovitis score was determined in 666 synovial specimens: normal synovium, n = 33; post-traumatic arthropathy (PtA), n = 29; osteoarthritis (OA), n = 221; psoriatic arthritis (PsA), n = 42; and rheumatoid arthritis (RA), n = 341. The discriminatory abilities of the score and its components were quantified with binary and multicategory receiver operating characteristic (ROC) analysis. The score differentiated all arthropathies accurately from normal tissue (area under the ROC curve, AUC: 0.87,0.98) and RA from OA or PtA (AUC: 0.85 for both), but could not distinguish well within pairs of inflammatory or degenerative arthropathies. AUCs of the intimal hyperplasia and stromal cellularity components correlated with the AUCs of the complete score markedly more strongly (r = 0.94 and 0.91, respectively) than the inflammatory infiltration component (r = 0.60). Multicategory ROC analysis ranked the score several-fold higher than any of its components, and the components in the order stromal cellularity>intimal hyperplasia>infiltration. Conclusion:, Combining three distinct histological parameters into a three-component score produces greatly increased overall diagnostic power. The discriminatory ability of the score stems more from measuring proliferative than infiltrative aspects of synovitis. [source] Intraoperative portal vein blood flow predicts allograft and patient survival following liver transplantationHPB, Issue 3 2010Austin L. Spitzer Abstract Background:, We hypothesized that operative variables might predict survival following liver transplantation. Methods:, We examined perioperative variables from 469 liver transplants carried out at the University of Washington during 2003,2006. Logistic regression determined the variables' contributions to survival at 30, 90 and 365 days. Results:, Portal vein blood flow (>1 l/min) was significant to patient survival at 30, 90 and 365 days. Complete reperfusion was only a significant predictor of survival at 30 days. This provided model receiver operating characteristic (ROC) area under the curve (AUC) statistics of 0.93 and 0.87 for 30 and 90 days, respectively. At 365 days, hepatic artery blood flow (>250 ml/min) combined with portal vein blood flow was significantly predictive of survival, with an AUC of 0.74. A subset analysis of 110 transplants demonstrated improved 1-year survival with more aggressive vascular revisions. Discussion:, Portal vein blood flow is a significant predictor of survival after liver transplantation. Initially, the liver's survival is based on portal vein blood flow; however, subsequent biliary problems and patient demise result from both poor portal vein and inadequate hepatic artery blood flow. [source] Permutation tests for factorially designed neuroimaging experimentsHUMAN BRAIN MAPPING, Issue 3 2004John Suckling Abstract Permutation methods for analysis of functional neuroimaging data acquired as factorially designed experiments are described and validated. The F ratio was estimated for main effects and interactions at each voxel in standard space. Critical values corresponding to probability thresholds were derived from a null distribution sampled by appropriate permutation of observations. Spatially informed, cluster-level test statistics were generated by applying a preliminary probability threshold to the voxel F maps and then computing the sum of voxel statistics in each of the resulting three-dimensional clusters, i.e., cluster "mass." Using simulations comprising two between- or within-subject factors each with two or three levels, contaminated by Gaussian and non-normal noise, the voxel-wise permutation test was compared to the standard parametric F test and to the performance of the spatially informed statistic using receiver operating characteristic (ROC) curves. Validity of the permutation-testing algorithm and software is endorsed by almost identical performance of parametric and permutation tests of the voxel-level F statistic. Permutation testing of suprathreshold voxel cluster mass, however, was found to provide consistently superior sensitivity to detect simulated signals than either of the voxel-level tests. The methods are also illustrated by application to an experimental dataset designed to investigate effects of antidepressant drug treatment on brain activation by implicit sad facial affect perception in patients with major depression. Antidepressant drug effects in left amygdala and ventral striatum were detected by this software for an interaction between time (within-subject factor) and group (between-subject factor) in a representative two-way factorial design. Hum. Brain Mapping 22:193,205, 2004. © 2004 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||||||||