Intraclass Correlation (intraclass + correlation)

Distribution by Scientific Domains

Terms modified by Intraclass Correlation

  • intraclass correlation coefficient

  • Selected Abstracts

    The De-Escalating Aggressive Behaviour Scale: development and psychometric testing

    Johannes Nau
    Abstract Title.,The De-Escalating Aggressive Behaviour Scale: development and psychometric testing. Aim., This paper is a report of a study to develop and test the psychometric properties of a scale measuring nursing students' performance in de-escalation of aggressive behaviour. Background., Successful training should lead not merely to more knowledge and amended attitudes but also to improved performance. However, the quality of de-escalation performance is difficult to assess. Method., Based on a qualitative investigation, seven topics pertaining to de-escalating behaviour were identified and the wording of items tested. The properties of the items and the scale were investigated quantitatively. A total of 1748 performance evaluations by students (rater group 1) from a skills laboratory were used to check distribution and conduct a factor analysis. Likewise, 456 completed evaluations by de-escalation experts (rater group 2) of videotaped performances at pre- and posttest were used to investigate internal consistency, interrater reliability, test,retest reliability, effect size and factor structure. Data were collected in 2007,2008 in German. Findings., Factor analysis showed a unidimensional 7-item scale with factor loadings ranging from 0·55 to 0·81 (rater group 1) and 0·48 to 0·88 (rater group 2). Cronbach's alphas of 0·87 and 0·88 indicated good internal consistency irrespective of rater group. A Pearson's r of 0·80 confirmed acceptable test,retest reliability, and interrater reliability Intraclass Correlation 3 ranging from 0·77 to 0·93 also showed acceptable results. The effect size r of 0·53 plus Cohen's d of 1·25 indicates the capacity of the scale to detect changes in performance. Conclusion., Further research is needed to test the English version of the scale and its validity. [source]

    The six-minute walk test in outpatients with obesity: reproducibility and known group validity

    Ulla Evers Larsson
    Abstract Background and Purpose.,To assess the reproducibility and validity of the six-minute walk test (6MWT) in men and women with obesity in order to facilitate evaluation of treatment outcome.,Method.,A test,retest design was used to test reproducibility and a comparative design to test known group validity. Forty-three obese outpatients (16 male), mean age 47 (21,62) years, mean body mass index (BMI) 40 (3,62)kg-m,2 performed the 6MWT twice within one week. Intraclass correlation (ICC1.1) and measurement error (Sw) were calculated from the mean square values derived from a one-way repeated-measures ANOVA (fixed effect model). The reproducibility was also analysed by means of coefficient of variation (CV) and the Bland Altman method including 95% limits of agreement. The variance of the distance walked was analysed by means of regressions. The known group validity of the 6MWT (distance walked and the work of walking) in obese participants was shown by comparisons with 41 lean participants (18 male), mean age 47 (24,65) years, mean BMI 22.7kg-m,2 (19,25).,Results.,The obese group walked 534,m (confidence interval [CI] 508,560 the first and 552,m (CI 523,580) the second walk (p < 0.001). Sw was 25,m, CV 4.7%, ICC1.1 was 0.96. The limits of agreement were ,46,m+80,m. The validity tests showed that they walked 162,m shorter (p < 0.001) and performed much heavier work (p < 0.001) than the lean group. In the obese group, BMI alone explained 38% of the variance of the distance walked.,Conclusions.,The 6MWT showed good reproducibility and known group validity and can be recommended for evaluating walking ability in subjects with obesity. For individual evaluation, however, an improved walking distance of at least 80,m was required to make the difference clinically significant. Despite shorter walking distance the obese participants performed heavier work than the lean. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Poorly performing physicians: Does the script concordance test detect bad clinical reasoning?,

    François Goulet MD
    Abstract Introduction Evaluation of poorly performing physicians is a worldwide concern for licensing bodies. The Collège des Médecins du Québec currently assesses the clinical competence of physicians previously identified with potential clinical competence difficulties through a day-long procedure called the Structured Oral Interview (SOI). Two peer physicians produce a qualitative report. In view of remediation activities and the potential for legal consequences, more information on the clinical reasoning process (CRP) and quantitative data on the quality of that process is needed. This study examines the Script Concordance Test (SCT), a tool that provides a standardized and objective measure of a specific dimension of CRP, clinical data interpretation (CDI), to determine whether it could be useful in that endeavor. Methods Over a 2-year period, 20 family physicians took, in addition to the SOI, a 1-hour paper-and-pencil SCT. Three evaluators, blind as to the purpose of the experiment, retrospectively reviewed SOI reports and were asked to estimate clinical reasoning quality. Subjects were classified into 2 groups (below and above median of the score distribution) for the 2 assessment methods. Agreement between classifications is estimated with the use of the Kappa coefficient. Results Intraclass correlation for SOI was 0.89. Cronbach alpha coefficient for the SCT was 0.90. Agreement between methods was found for 13 participants (Kappa: 0.30, P = 0.18), but 7 out of 20 participants were classified differently in both methods. All participants but 1 had SCT scores below 2 SD of panel mean, thus indicating serious deficiencies in CDI. Discussion The finding that the majority of the referred group did so poorly on CDI tasks has great interest for assessment as well as for remediation. In remediation of prescribing skills, adding SCT to SOI is useful for assessment of cognitive reasoning in poorly performing physicians. The structured oral interview should be improved with more precise reporting by those who assess the clinical reasoning process of examinees, and caution is recommended in interpreting SCT scores; they reflect only a part of the reasoning process. [source]

    Association between tobacco control policies and smoking behaviour among adolescents in 29 European countries

    ADDICTION, Issue 11 2009
    Anne Hublet
    ABSTRACT Aims To investigate the associations between well-known, cost-effective tobacco control policies at country level and smoking prevalence among 15-year-old adolescents. Design Multi-level modelling based on the 2005,06 Health Behaviour in School-aged Children Study, a cross-national study at individual level, and with country-level variables from the Tobacco Control Scale and published country-level databases. Setting Twenty-nine European countries. Participants A total of 25 599 boys and 26 509 girls. Main outcome measures Self-reported regular smoking defined as at least weekly smoking, including daily smoking (dichotomous). Findings Interaction effects between gender and smoking policies were identified, therefore boys and girls were analysed separately. Large cross-national differences in smoking prevalence were documented. Intraclass correlations (ICC) of 0.038 (boys) and 0.035 (girls) were found. In the final multi-level model for boys, besides the significance of the individual variables such as family affluence, country-level affluence and the legality of vending machines were related significantly to regular smoking [b(country affluence) = ,0.010; b(partial restriction vending machines) = ,0.366, P < 0.05]. Price policy was of borderline significance [b(price policy) = ,0.026, P = 0.050]. All relationships were in the expected direction. The model fit is not as good for girls; only the legality of vending machines had a borderline significance in the final model [b(total ban vending machines) = ,0.372, P = 0.06]. Conclusions For boys, some of the currently recommended tobacco control policies may help to reduce smoking prevalence. However, the model is less suitable for girls, indicating gender differences in the potential efficacy of smoking policies. Future research should address this issue. [source]

    Heritability of different measures of smooth pursuit eye tracking dysfunction: A study of normal twins

    PSYCHOPHYSIOLOGY, Issue 6 2000
    Joanna Katsanis
    Research studies have found that smooth pursuit eye movement dysfunction may serve as an index of genetic liability to develop schizophrenia. The heritability of various measures of smooth pursuit eye tracking proficiency and the saccades that occur during smooth pursuit was examined in 64 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs. Two age cohorts were assessed (11,12 and 17,18 years of age). Intraclass correlations indicated significant similarity in the MZ twins for almost all measures in both age cohorts, whereas few of the DZ twin correlations attained significance. Biometrical modeling indicated that genetic mechanisms influence performance on both global and specific eye tracking measures, accounting for about 40% to 60% of the variance. These findings suggest that the underlying brain systems responsible for smooth pursuit and saccade generation during pursuit are under partial genetic control. [source]

    Comparison of the Melbourne Assessment of Unilateral Upper Limb Function and the Quality of Upper Extremity Skills Test in hemiplegic CP

    K Klingels MSc
    This study investigated interrater reliability and measurement error of the Melbourne Assessment of Unilateral Upper Limb Function (Melbourne Assessment) and the Quality of Upper Extremity Skills Test (QUEST), and assessed the relationship between both scales in 21 children (15 females, six males; mean age 6y 4mo [SD 1y 3mo], range 5,8y) with hemiplegic CP. Two raters scored the videotapes of the assessments independently in a randomized order. According to the House Classification, three participants were classified as level 1, one participant as level 3, eight as level 4, three as level 5, one participant as level 6, and five as level 7. The Melbourne Assessment and the QUEST showed high interrater reliability (intraclass correlation 0.97 for Melbourne Assessment; 0.96 for QUEST total score; 0.96 for QUEST hemiplegic side). The standard error of measurement and the smallest detectable difference was 3.2% and 8.9% for the Melbourne Assessment and 5.0% and 13.8% for the QUEST score on the hemiplegic side. Correlation analysis indicated that different dimensions of upper limb function are addressed in both scales. [source]

    Psychometric properties of the Chinese version of the Swanson, Nolan, and Pelham, version IV scale , parent form

    Susan Shur-Fen Gau
    Abstract This study aimed to establish the psychometric properties of parent ratings on the Chinese version of the Swanson, Nolan, and Pelham IV scale (SNAP-IV) in a school-based sample of 3534 students in grades 1 to 8 from two cities and two suburbs in Taiwan and 189 children diagnosed with attention deficit/hyperactivity disorder (ADHD) (aged 6 to 15) consecutively recruited from a medical center in Taipei. Parents completed the Chinese versions of the SNAP-IV, Strengths and Difficulties Questionnaire, and Child Behavior Checklist. The Chinese SNAP-IV demonstrated similar three factor structure (Inattention, Hyperactivity/Impulsivity, and Oppositional) as its English version, and satisfactory test,retest reliability (intraclass correlation = 0.59,0.72), internal consistency (alpha = 0.88,0.90), concurrent validity (Pearson correlations = 0.56,0.72), and discriminant validity. Boys scored higher than girls across the eight school grade levels. The SNAP-IV clearly distinguished children with ADHD from school-based participants. Comorbidity with oppositional defiant disorder/conduct disorder predicted higher SNAP-IV scores among children with ADHD. Our findings suggest that the Chinese SNAP-IV is a reliable and valid instrument for rating ADHD-related symptoms in both clinical and community settings in Taiwan. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Detection of Mild Hyposalivation in Elderly People Based on the Chewing Time of Specifically Designed Disc Tests: Diagnostic Accuracy

    DrOdont, Isabelle Madinier DDS
    OBJECTIVES: To compare sialometry with chewing time (including swallowing) of specifically designed disc tests. DESIGN: Index test versus reference standard (sialometry; 60 patients); reliability study (10 patients). SETTING: Outpatient dental clinic and geriatric ward, Nice University Hospital, France. PARTICIPANTS: Thirty adults and 30 older patients (mean ages 47 and 84). INTERVENTION: Index test assessment in patients with and without hyposalivation. MEASUREMENTS: Data from medical files, interviews and oral examination were collected. Sialometry (stimulated salivary flow rate (SSFR) mL/min) and disc chewing times (seconds) were measured. RESULTS: Sialometry was too long and was inappropriate for five of the 30 older persons. Chewing times were negatively correlated to sialometry results (Spearman correlation coefficient (R)=0.77, P<.001). The threshold to diagnose hyposalivation (SSFR <1 mL/min) was 40 seconds (area under the receiver operating characteristic curve (AUC)=0.921, 100% sensitivity, 72% specificity). Twenty-seven subjects with a SSFR less than 1.5 mL/min had a chewing time longer than 40 seconds, suggesting that mild hyposalivation and eating difficulties were related (AUC=0.941, 93% sensitivity, 88% specificity). Mean chewing time was greater with xerostomia (51.9 vs 30.7 seconds, P<.001) but not with dental pain (39.5 vs 39.9, P=.96). Masticatory percentage (e.g., pairs of antagonistic teeth) had no effect on chewing time (SSFR <1 mL/min, AUC=0.921; SSFR <1.5 mL/min, AUC=0.950). Reliability was better for the disc test than for sialometry (intraclass correlation 0.85 vs 0.70). CONCLUSION: This disc test was conceived to detect mild hyposalivation in geriatric patients with impaired dental health. Early detection of hyposalivation could help to suppress or avoid xerostomia-inducing drugs and to prevent oral infections and dental caries. [source]

    Tests of Muscle Strength and Physical Function: Reliability and Discrimination of Performance in Younger and Older Men and Older Men with Mobility Limitations

    Nathan K. LeBrasseur PT
    OBJECTIVES: To compare the reliability of muscle strength and physical function measures in younger and older men. DESIGN: Cross-sectional. SETTING: Academic research center. PARTICIPANTS: Thirty younger men, 31 older men, and 39 older men with mobility limitations. MEASUREMENTS: Test,retest measures of one repetition maximum (1 RM), unloaded and loaded 50-m walk and stair climb, and a lift-and-lower task. Reliability was assessed using intraclass correlation (ICC) analysis and the Bland-Altman method. RESULTS: Leg and chest press 1 RM measures identified significant differences between the groups, exhibited excellent test,retest reliability in younger men, older men, and older men with mobility limitations (ICCs=0.946,0.994) and minimal bias between Trials 1 and 2 (Bland-Altman=improvement of 21.1 and 1.1 N for leg and chest press, respectively). Test,retest measures of the time to walk 50 m and climb 12 steps also demonstrated excellent agreement (ICCs=0.980,0.988 and 0.942,992, respectively) and minimal bias (Bland-Altman=0.755,1.007 and 0.141,0.361 seconds faster, respectively). When a subject repeated these measures carrying a modest load, ICCs remained greater than 0.940, bias was similar, and the tests better discriminated between the groups. The lift-and-lower measure demonstrated excellent agreement (ICCs=0.925,0.947) and minimal bias (1.4,2.9 more shelves) and revealed significant differences between groups. CONCLUSION: Measures of muscle strength and physical function can be performed in younger men, older men, and older men with mobility limitations with high reliability. In future clinical trials, more-challenging measures of performance may better discriminate between higher-functioning study participants. [source]

    Analysis of Heritability of Hormonal Responses to Alcohol in Twins: Beta-Endorphin as a Potential Biomarker of Genetic Risk for Alcoholism

    ALCOHOLISM, Issue 3 2000
    J. C. Froehlich
    Background: Hormonal responses to alcohol have been reported to differ in subjects with and without a family history of alcoholism which suggests that alcohol-induced hormonal changes might be used to identify individuals who are at elevated genetic risk for developing alcoholism. However, before a biological response can be used as a marker of genetic risk for disease, it must first be demonstrated that the response is, in fact, heritable. The present study was designed to determine whether hormonal responses to alcohol are heritable. Methods: The adrenocorticotropic hormone (ACTH), beta-endorphin (,-E), cortisol (CORT), and prolactin (PRL) responses to alcohol were examined in male and female identical (monozygotic or MZ) and fraternal (dizygotic or DZ) twin pairs. Male subjects consumed 0.35g ethanol/kg body weight (BW) and female consumed 0.325 g ethanol/kg BW in each of two alcohol drinking sessions administered 1 hr apar (total dose of 0.7 g/kg BW in males and 0.65 g/kg BW in females). Plasma hormone content was analyzed in samples collected before (resting conditions) and at 15, 60, 75, 120, 180, and 240 min after onset of drinking. Hormonal responses to alcohol were examined with twin analyses using the TWINAN90 program. A separate analysis was performed for each of the four hormones. A subset of subjects from each zygosity was seen on two separate occasions to establish retest reliability. Heritability of hormonal responses to alcohol was estimated using the intraclass correlation approach before and after removing the contribution of covariates that have the potential of influencing the plasma levels of these hormones. Results: Resting plasma levels of all four hormones were within the expected range, and the ,-E, ACTH, and PRL responses to the alcohol challenge evidenced good test-retest reliability. Of the four hormones examined, the only one that showed significant heritability after alcohol drinking was ,-E. Heritability estimates were not altered for any of the four hormones after removal of the variance contributed by covariates, such as gender and age. Conclusions: Taken together with other recent findings, the results suggest that the ,-E response to alcohol may represent a new biomarker that can be used to identify individuals who are at elevated genetic risk for developing alcoholism. [source]

    Reliability and validity of the direct observation clinical encounter examination (DOCEE)

    MEDICAL EDUCATION, Issue 3 2003
    Hossam Hamdy
    Context, The College of Medicine and Medical Sciences at the Arabian Gulf University, Bahrain, replaced the traditional long case/short case clinical examination on the final MD examination with a direct observation clinical encounter examination (DOCEE). Each student encountered four real patients. Two pairs of examiners from different disciplines observed the students taking history and conducting physical examinations and jointly assessed their clinical competence. Objectives, To determine the reliability and validity of the DOCEE by investigating whether examiners agree when scoring, ranking and classifying students; to determine the number of cases and examiners necessary to produce a reliable examination, and to establish whether the examination has content and concurrent validity. Subjects, Fifty-six final year medical students and 22 examiners (in pairs) participated in the DOCEE in 2001. Methods, Generalisability theory, intraclass correlation, Pearson correlation and kappa were used to study reliability and agreement between the examiners. Case content and Pearson correlation between DOCEE and other examination components were used to study validity. Results, Cronbach's alpha for DOCEE was 0·85. The intraclass and Pearson correlation of scores given by specialists and non-specialists ranged from 0·82 to 0·93. Kappa scores ranged from 0·56 to 1·00. The overall intraclass correlation of students' scores was 0·86. The generalisability coefficient with four cases and two raters was 0·84. Decision studies showed that increasing the cases from one to four improved reliability to above 0·8. However, increasing the number of raters had little impact on reliability. The use of a pre-examination blueprint for selecting the cases improved the content validity. The disattenuated Pearson correlations between DOCEE and other performance measures as a measure of concurrent validity ranged from 0·67 to 0·79. Conclusions, The DOCEE was shown to have good reliability and interrater agreement between two independent specialist and non-specialist examiners on the scoring, ranking and pass/fail classification of student performance. It has adequate content and concurrent validity and provides unique information about students' clinical competence. [source]

    Parentage versus two-generation analyses for estimating pollen-mediated gene flow in plant populations

    MOLECULAR ECOLOGY, Issue 8 2005
    Abstract Assessment of contemporary pollen-mediated gene flow in plants is important for various aspects of plant population biology, genetic conservation and breeding. Here, through simulations we compare the two alternative approaches for measuring pollen-mediated gene flow: (i) the neighborhood model , a representative of parentage analyses, and (ii) the recently developed twogener analysis of pollen pool structure. We investigate their properties in estimating the effective number of pollen parents (Nep) and the mean pollen dispersal distance (,). We demonstrate that both methods provide very congruent estimates of Nep and ,, when the methods' assumptions considering the shape of pollen dispersal curve and the mating system follow those used in data simulations, although the neighborhood model exhibits generally lower variances of the estimates. The violations of the assumptions, especially increased selfing or long-distance pollen dispersal, affect the two methods to a different degree; however, they are still capable to provide comparable estimates of Nep. The neighborhood model inherently allows to estimate both self-fertilization and outcrossing due to the long-distance pollen dispersal; however, the twogener method is particularly sensitive to inflated selfing levels, which in turn may confound and suppress the effects of distant pollen movement. As a solution we demonstrate that in case of twogener it is possible to extract the fraction of intraclass correlation that results from outcrossing only, which seems to be very relevant for measuring pollen-mediated gene flow. The two approaches differ in estimation precision and experimental efforts but they seem to be complementary depending on the main research focus and type of a population studied. [source]

    Six-minute walk test in obese children and adolescents: Reproducibility and validity,

    Gunilla Morinder
    Abstract Background and Purpose.,The six-minute walk test (6MWT) is increasingly used in clinical practice. The aims of this study were to determine the reproducibility of the 6MWT in obese children and adolescents, to describe walking capacity in this population and compare the results with values from normal-weight children (known group validity), and, finally, to describe the correlation between distance walked and estimated maximum oxygen uptake (VO2max).,Methods.,Reproducibility was determined by a test,retest design and known group validity by a comparative design. The 6MWT was first test,retested in 49 obese children (30 boys, 19 girls, 8,16 years, body mass index [BMI] 24.9,52.1,kg?m,2). Then, for validation, 250 obese children (126 boys, 124 girls, 8,16 years, BMI 23.2,57,kg/m2) and 97 normal-weight children (48 boys, 49 girls, 8,16 years, BMI 13.3,23.2,kg·m,2) performed the 6MWT. The obese children also performed a sub-maximal bicycle ergometry test.,Results.,In the test,retest, the obese children walked 571,m the first test and 57,m the second (p = 0.578). The measurement error (Sw) was 24,m, coefficient of variation (CV): 4.3% and the intraclass correlation (ICC1:1): 0.84. Repeatability was 68,m, and limits of agreement were +71 and ,65,m. In comparison mean (standard deviation), six-minute walk distance (6MWD) in the obese children was 571,m (65.5), and in the normal-weight children, 663,m (61.1) (p < 0.001). The correlation between 6MWD and estimated VO2max (r = 0.34) was low.,Conclusions.,The 6MWT showed good reproducibility and known group validity, and can be recommended for use in clinical practice in the studied population. To evaluate individual outcomes after intervention, the 6MWD needs to change by >68,m to be statistically significant. The 6MWD performed by obese children averaged 86% of the distance normal-weight children walked. In obese children, the correlation between 6MWD and estimated VO2max was low, hence the 6MWT cannot substitute a bicycle ergometry test. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Reliability and concurrent validity of the Expanded Timed Up-and-Go test in older people with impaired mobility

    Pernille Botolfsen
    Abstract Background and Purpose.,,Expanded Timed Up-and-Go' (ETUG) was developed to assess each of the subtasks of the ,Timed Up-and-Go' (TUG). The aim of the study was to test the intrarater, interrater, test,retest reliability and internal consistency of the ETUG, and the concurrent validity with the TUG.,Methods.,The present study is a reliability and a validity study. Twenty-eight subjects (80 ± 4.1 years) with balance and gait problems were included. Three raters timed the ETUG subtasks from a video, using a computer-based scoring programme, and the total ETUG time was calculated. TUG was registered by a regular stopwatch.,Results.,The intrarater and interrater reliability (intraclass correlation [ICC][1,1]) ranged from 0.55 to 0.97. The test,retest reliability (ICC[1,1]) ranged from 0.54 to 0.85. The absolute measurement error of the total time (1.96 Sw) was 2.8 seconds. The internal consistency (Cronbach's alpha) was 0.74. The correlation (Pearson's r) between ETUG total time and TUG after correcting for attenuation caused by restricted reliability in each of the measures was 0.85.,Conclusion.,The ETUG scored from a video shows a good reliability for experienced raters and acceptable internal consistency. The ETUG showed a higher reliability than TUG when tested on the same sample of older subjects with impaired mobility, and the high concurrent validity between ETUG and TUG suggests that the two tests may have similar properties. Since ETUG also adds new information compared with TUG, we suggest that ETUG is an interesting alternative to existing clinical tests of mobility. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    A limited sampling strategy for tacrolimus in renal transplant patients

    Binu S. Mathew
    WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT , Tacrolimus trough concentration is being currently used for dose individualization. , Limited sampling strategies (LSS) have been developed and validated for renal transplant patients. , Earlier literature has suggested that measurement of tacrolimus AUC is more reliable than trough with respect to both rejection and nephrotoxicity. WHAT THIS STUDY ADDS , Four thousand renal transplants take place annually in India, with many patients prescribed tacrolimus in combination with mycophenolate and steroid. , In this study a LSS with two points, i.e. trough and 1.5 h postdose was developed and validated to estimate AUC0,12. , The added benefit of only a single additional sample with completion of blood collection in 1.5 h and minimum additional cost makes this a viable LSS algorithm in renal transplant patients. , In patients having tacrolimus trough concentrations outside the recommended range (<3 and >10 ng ml,1 in the treatment protocol in our institution) or having side-effects in spite of trough concentrations in the desired range, we can estimate AUC using this LSS for a better prediction of exposure. AIMS To develop and validate limited sampling strategy (LSS) equations to estimate area under the curve (AUC0,12) in renal transplant patients. METHODS Twenty-nine renal transplant patients (3,6 months post transplant) who were at steady state with respect to tacrolimus kinetics were included in this study. The blood samples starting with the predose (trough) and collected at fixed time points for 12 h were analysed by microparticle enzyme immunoassay. Linear regression analysis estimated the correlations of tacrolimus concentrations at different sampling time points with the total measured AUC0,12. By applying multiple stepwise linear regression analysis, LSS equations with acceptable correlation coefficients (R2), bias and precision were identified. The predictive performance of these models was validated by the jackknife technique. RESULTS Three models were identified, all with R2 , 0.907. Two point models included one with trough (C0) and 1.5 h postdose (C1.5), another with trough and 4 h postdose. Increasing the number of sampling time points to more than two increased R2 marginally (0.951 to 0.990). After jackknife validation, the two sampling time point (trough and 1.5 h postdose) model accurately predicted AUC0,12. Regression coefficient R2 = 0.951, intraclass correlation = 0.976, bias [95% confidence interval (CI)] 0.53% (,2.63, 3.69) and precision (95% CI) 6.35% (4.36, 8.35). CONCLUSION The two-point LSS equation [AUC0,12 = 19.16 + (6.75.C0) + (3.33.C1.5)] can be used as a predictable and accurate measure of AUC0,12 in stable renal transplant patients prescribed prednisolone and mycophenolate. [source]

    Predictors for visual field progression and the effects of treatment with dorzolamide 2% or brinzolamide 1% each added to timolol 0.5% in primary open-angle glaucoma

    Antonio Martínez
    Abstract. Purpose:, This study aims to identify progression factors in patients with primary open-angle glaucoma (POAG), including the effects of treatment with dorzolamide 2% or brinzolamide 1%, each added to timolol 0.5%. Methods:, A sample of 161 POAG patients were prospectively randomized to receive either dorzolamide 2% (DT) or brinzolamide 1% (BT) b.i.d., each added to timolol 0.5%, during a 60-month, evaluator-masked study. Progression was determined by perimetric criteria. Factors associated with visual field progression were estimated using a conditional Cox hazard model with patient intraclass correlation and were expressed as hazard ratios (HRs) with 95% confidence intervals (95% CIs). Results:, Predictive baseline factors were lower diastolic blood pressure (DBP), lower mean arterial pressure (MAP), antihypertensive treatment, lower end-diastolic velocity (EDV) in the ophthalmic artery (OA) and short posterior ciliary artery (SPCA), and a higher resistivity index (RI) in the OA and SPCA. Progression risk decreased by approximately 30% and 20% with each centimetre per second increase of EDV in the OA and SPCA, respectively, from baseline to the last follow-up visit. Each RI decrease (or increase) of 0.01 unit in the OA or SPCA was associated with an approximate 20% decrease (or increase) in risk for progression. In a multivariate analysis, progression risk was significantly lower in eyes treated with DT (HR = 0.65, 95% CI 0.41,0.90) compared with those treated with BT. Conclusions:, Progression increased with lower DBP, lower MAP, antihypertensive medication, lower EDV in the OA and SPCA, and higher RI in the OA and SPCA. The risk for progression in patients treated with DT was half that in patients treated with BT. [source]

    Validation of the Clinical COPD Questionnaire as a psychophysical outcome measure in adult laryngotracheal stenosis

    S.A.R. Nouraei
    Objectives:, To validate the Clinical Chronic Obstructive Pulmonary Disease Questionnaire (CCQ), a patient-administered instrument developed for bronchopulmonary disease as a disease-specific psychophysical outcome measure for adult laryngotracheal stenosis. Design:, Prospective observational study. Settings:, Tertiary/National referral airway reconstruction centre. Participants:, Thirty-three tracheostomy-free patients undergoing endoscopic laryngotracheoplasty. Main outcome measures:, CCQ and the Medical Research Council (MRC) Dyspnoea scale, a previously validated but more limited scale, were administered to patients 2 weeks before surgery, preoperatively, and 2 weeks after endoscopic laryngotracheoplasty. Pulmonary function was assessed preoperatively. Internal consistency was assessed with Cronbach , statistics and test,retest reliability was determined using intraclass correlation. Correlations between CCQ and MRC scale, and pulmonary function were used to assess convergent and divergent validity respectively. Instrument responsiveness was assessed by correlating total and domain-specific CCQ scores with anatomical disease severity and post-treatment effect size. Results:, There were 12 males and 21 females. Mean age was 44 ± 15 years. Cronbach , coefficient and intraclass correlation coefficient were 0.88 and 0.95 respectively. Total and domain-specific CCQ scores significantly correlated with the MRC scores (P < 0.001) and significant correlations between CCQ and peak expiratory flow rate and FEV1 were identified (P < 0.03). There were statistically significant changes in total and domain-specific CCQ scores when different stenosis severities were compared. Clinical COPD Questionnaire scores also changed significantly and congruently following surgery (P < 0.05 in both cases). Discussion:, Clinical COPD Questionnaire is a valid and sensitive instrument for assessing symptom severity and levels of function and well-being in adult patients with laryngotracheal stenosis and can be used as a patient-centred disease-specific outcome measure for this condition. [source]

    Lots of target variance: An update of SRM using the HEXACO personality inventory

    Reinout E. de Vries
    Abstract According to previous studies based on the Social Relations Model (SRM), most of the variance in observer reports of personality is perceiver and relationship variance, and not much is target variance. However, most SRM studies have employed short adjective scales instead of personality questionnaires. Results based on the HEXACO-PI-R in family and work groups showed high levels of consensus (target variance) and self-other agreement for all traits and, except for Honesty,Humility and Openness to Experience, low levels of generalized rater bias (perceiver variance) and of assumed similarity. Additionally, intraclass correlations suggested a 'group personality' for some traits. The findings suggest that the use of personality questionnaires in Social Relations Analyses may promote higher estimates of consensus in personality judgments. Copyright © 2010 John Wiley & Sons, Ltd. [source]

    Health-related quality of life of youth with inflammatory bowel disease: A comparison with published data using the PedsQL 4.0 generic core scales

    Jennifer Hauser Kunz PhD
    Abstract Background: This study compared youth and parent-proxy reports of health-related quality of life (HRQoL) among youth with inflammatory bowel disease (IBD) to published comparison group data and examined concordance between youth and parent-proxy reports of HRQoL. Methods: One hundred thirty-six youth and parent-proxy reports on the PedsQL 4.0 Generic Core Scales were compared to published data from chronically ill, acutely ill, and healthy comparison groups using independent samples t -tests. Reporter agreement was examined using paired samples t -tests and intraclass correlations (ICCs). Results: Youth with IBD reported lower psychosocial functioning than the healthy comparison group, higher physical and social functioning than the chronically ill group, and lower school functioning than all published comparison groups. Parent-proxy reports of youth HRQoL were higher than the chronically ill group, but lower than the healthy group on all scales except psychosocial functioning. Youth with active IBD reported lower physical health domain scores than youth with inactive disease. Concordance between youth and parent-proxy reports was moderate, with the lowest agreement in school and social functioning. Conclusions: Youth with IBD and their parents rate HRQoL as lower than healthy youth but do not perceive the impact of IBD to be as limiting as in other chronic conditions. Youth report suggests that IBD may be particularly detrimental to HRQoL in the school functioning domain. Moderate agreement between parent and youth reports substantiates continued use of multiple informants in studies of pediatric HRQoL. Inflamm Bowel Dis 2010 [source]

    Morphometric characterization of murine articular cartilage,Novel application of confocal laser scanning microscopy

    Kathryn S. Stok
    Abstract A new technique for characterization of the three-dimensional morphology of murine articular cartilage is proposed. The technique consists of a novel application of confocal laser scanning microscopy (CLSM), where the objective was to develop and validate it for cartilage measurements in murine joints. Murine models are used in arthritis research, because they are well-described for manipulating the disease pathophysiology, facilitating our understanding of the disease, and identifying new targets for therapy. A calibration and reproducibility study was carried out to provide a consistent testing methodology for quantification of murine joints. The proximal tibial condyles from male C57BL/6 mice were scanned using a CLS microscope with an isotropic voxel size of 5.8 ,m. Measurements and analyses were repeated three times on different days, and in a second step the analysis was repeated three times for a single measurement. Calculation of precision errors (coefficient of variation) for cartilage thickness and volume was made. The bias of the system was estimated through comparison with histology. This technique showed good precision, with errors in the repeated analysis ranging from 0.63% (lateral thickness) to 3.48% (medial volume). The repeated analysis alone was robust, with intraclass correlations for the different compartments between 0.918 and 0.991. Measurement bias was corrected by scaling the confocal images to 32% of their width to match histology. CLSM provided a fast and reproducible technique for gathering 3D image data of murine cartilage and will be a valuable tool in understanding the efficacy of arthritis treatments in murine models. Microsc. Res. Tech. 2009. © 2009 Wiley-Liss, Inc. [source]

    Discovery and transmission of functional QTL in the pedigree of an elite soybean cultivar Suinong14

    PLANT BREEDING, Issue 3 2010
    J. Qin
    With 3 figures and 5 tables Abstract In this study, we extended in silico mapping for single trait to analyse data from multiple environments by calculating intraclass correlations and to mapping pleiotropic QTL for multiple traits by defining new statistic to measure the correlation between multiple traits and the marker. Data sets include phenotypes of eight agronomic traits obtained from six different ecologic environments and years, and genotypic information from 477 polymorphic markers on 14 ancestral lines in the pedigree of ,Suinong14'. With in silico mapping, a total of 39 markers distributed on 14 linkage groups are detected as QTL responsible for eight agronomic traits and 10 QTL are identified as having pleiotropic effects. Tracing transmission of functional QTL in the pedigree indicated that certain QTL, such as Sat_036 on linkage group D1a, Satt182 on linkage group L, and Satt726 on linkage group B2 may be responsible for the contribution of exotic germplasm to the improved cultivars. [source]

    Heart Rate Variability by Triangular Index in Infants Exposed Prenatally to Cocaine

    M.B.A., Sudhir Ken Mehta M.D.
    Background: In adults, heart rate variability triangular index (HRVi) is a highly reproducible measure of heart rate variability (HRV), which makes it more suitable for use in longitudinal studies. Although normative data have been published for newborns, studies in infants with pathological conditions are lacking. Methods: From 1997 to 2000, within the first 4 days of life, we prospectively evaluated HRVi in cocaine-exposed asymptomatic newborns (N = 97) by Holter monitoring. Their data were compared with infants from two control groups (one with no in utero drug exposure, N = 102; the other with exposure to alcohol, nicotine, or marijuana but no cocaine, N = 111). Results: In assessing concordance between and within operators for HRVi, the intraclass correlations were 0.983 (95% Cl: 0.958, 0.994) and 0.997 (95% Cl: 0.984, 0.999), respectively. Infants with in utero cocaine exposure had significantly (P < 0.0001) lower HRVi than those exposed to other drugs and to no drugs in utero. If abnormal HRVi is defined as < fifth percentile for the no drug exposed group (HRVi < 8), 10% of the cocaine-exposed newborns, in contrast to 2% in each of the control groups (P = 0.003) had abnormal values. Conclusion: HRVi is a reliable measure to study heart rate variability in newborns. Asymptomatic infants with in utero cocaine exposure have lower HRVi. Our study supports the clinical use of an abnormal HRVi as a value < 8 for newborn infants. A.N.E. 2002;7(4):374,378 [source]

    A population-based study of macular thickness in full-term children assessed with Stratus OCT: normative data and repeatability

    Urban Eriksson
    Abstract. Purpose:, We aimed to determine normal macular thickness values, assessed with optical coherence tomography (OCT), in a population of full-term children of normal birthweight. Methods:, A total of 56 children, aged 5,16 years, randomly chosen from the population register, were examined with Stratus OCT. Only children with visual acuity < 0.2 logMAR, spherical equivalent of , 3 to + 3 D and astigmatism < 2 D were included. The fast macular map protocol was used and three examinations were performed in each eye. One eye was then randomized for further analyses. Mean values for the nine ETDRS areas, foveal minimum thickness and macular volume were calculated for 55 eyes. Coefficients of variance and intraclass correlations were calculated for each area. Results:, All children co-operated well and no child was excluded for lack of concentration. Mean ± standard deviation central macular thickness was 204 ± 19 ,m. Mean total macular volume was 7.11 ± 0.35 mm3. No correlations were found between age, gender and macular thickness. Coefficients of variance were < 2% and intraclass correlations were > 0.9 in all areas, except the foveal minimum. Conclusions:, Normal values for macular thickness in healthy full-term children were reported. As the Stratus OCT provides normal values only for adults, these data are a better alternative for comparison with children with retinal abnormalities. We concluded that OCT is suitable for examining the retina in children aged 5,16 years and has the same high level of repeatability as in adults. [source]

    NIKE: a new clinical tool for establishing levels of indications for cataract surgery

    Mats Lundström
    Abstract. Purpose:, The purpose of this study was to construct a new clinical tool for establishing levels of indications for cataract surgery, and to validate this tool. Methods:, Teams from nine eye clinics reached an agreement about the need to develop a clinical tool for setting levels of indications for cataract surgery and about the items that should be included in the tool. The tool was to be called ,NIKE' (Nationell Indikationsmodell för Kataraktextraktion). The Canadian Cataract Priority Criteria Tool served as a model for the NIKE tool, which was modified for Swedish conditions. Items included in the tool were visual acuity of both eyes, patients' perceived difficulties in day-to-day life, cataract symptoms, the ability to live independently, and medical/ophthalmic reasons for surgery. The tool was validated and tested in 343 cataract surgery patients. Validity, stability and reliability were tested and the outcome of surgery was studied in relation to the indication setting. Results:, Four indication groups (IGs) were suggested. The group with the greatest indications for surgery was named group 1 and that with the lowest, group 4. Validity was proved to be good. Surgery had the greatest impact on the group with the highest indications for surgery. Test-retest reliability test and interexaminer tests of indication settings showed statistically significant intraclass correlations (intraclass correlation coefficients [ICCs] 0.526 and 0.923, respectively). Conclusions:, A new clinical tool for indication setting in cataract surgery is presented. This tool, the NIKE, takes into account both visual acuity and the patient's perceived problems in day-to-day life because of cataract. The tool seems to be stable and reliable and neutral towards different examiners. [source]