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Results for “Reproducibility”

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At least 1,135 records · Page 63Linked to original sources

PubMed2002

Short-term reproducibility of T wave alternans measurement.

INTRODUCTION: Microvolt T wave alternans (TWA) has been proposed as a strong independent predictor of malignant ventricular tachyarrhythmias and sudden cardiac death. TWA reproducibility during bicycle stress test has not been previously investigated. We sought to assess the short-term reproducibility of TWA, as well as heart rate (HR) threshold for TWA, and its spatial distribution and magnitude. METHODS AND RESULTS: The study enrolled 42 patients who were able to complete two bicycle stress tests with HR at peak exercise >110 beats/min within 4 hours of each other and who had technically adequate recordings for TWA analysis during both tests. Concordant results for TWA determination were obtained in 39 (93%) of 42 cases. TWA was present during both tests in 23 patients and was absent during both tests in 16 patients. In the 23 patients with two positive tests, HR at the onset of TWA was not significantly different during the two tests. Further, the number of leads showing TWA and the magnitude of TWA were not significantly different between the two tests. CONCLUSION: TWA is characterized by satisfactory short-term reproducibility and, when present, by high temporal and spatial stability.

Death, Sudden, Cardiac↗

PubMed2002

Reproducibility of asystole during head-up tilt testing in patients with neurally mediated syncope.

Tilt induced prolonged asystole has been considered to identify a distinct subgroup of patients with neurally mediated syncope and management including permanent pacemaker implantation has been suggested. To evaluate the reproducibility of asystolic response during head-up tilt testing (HUT), 33 patients with neurally mediated syncope and asystolic response (> or = 3 seconds) during HUT prospectively underwent two consecutive tests 13 +/- 15 days apart. On repeat tilt testing asystole was reproduced in 12 patients (36%), while 8 patients still had a positive HUT, but without asystole. Remarkably, 13 patients (40%) had a negative repeat HUT. Among 12 patients with asystole on both HUTs there was no significant difference in duration of asystole (14 371 +/- 11 430 ms vs 13 707 +/- 10 470 ms, P = ns) and time to syncope (36 +/- 20 min vs 37 +/- 20 min, P = ns) during initial and repeat HUTs. In conclusion, asystole during tilt testing does not seem to be a reproducible response.

Adolescent↗

PubMed2002

How reproducible is the cardioinhibitory response to carotid sinus massage in fallers?

AIMS: To ascertain the reproducibility of the cardioinhibitory subtype of carotid sinus hypersensitivity (CICSH) in fallers. METHODS AND RESULTS: One hundred and seventy-five subjects with CICSH and unexplained or recurrent falls were randomized to pacemaker implantation or control. Sixty-four control subjects (61% female, mean age 71.8 years, median 2 falls in the previous year) completed one-year follow-up and had carotid sinus massage (CSM) performed on 4 occasions (twice before randomization, at 6 months and 1 year following randomization). CSM was performed sequentially on the right and then left sides, initially supine and then upright at 70 degrees head-up tilt by the same investigator. On each occasion CSM was discontinued once CICSH was demonstrated. CICSH was demonstrated on 82% of occasions, 75% on right CSM and 77% whilst the subject was supine. Before randomization, and at 6 months and 1 year, 91%, 67%, and 70% of subjects had reproducible CICSH respectively. Half had CICSH on all 4 occasions. Only 17% had a consistent response on the same side in the same position. CONCLUSIONS: In the majority of subjects CICSH is reproducible and this is more likely shortly after the initial response. However the cardioinhibitory response to CSM is inconsistent both in side elicited and subject position.

Accidental Falls↗

PubMed2001

Interobserver reproducibility of Gleason grading of prostatic carcinoma: urologic pathologists.

Gleason grading is now the most widely used grading system for prostatic carcinoma in the United States. However, there are only a few studies of the interobserver reproducibility of this system, and no extensive study of interobserver reproducibility among a large number of experienced urologic pathologists exists. Forty-six needle biopsies containing prostatic carcinoma were assigned Gleason scores by 10 urologic pathologists. The overall weighted kappa coefficient kappa(w) for Gleason score for each of the urologic pathologists compared with each of the remaining urologic pathologists ranged from 0.56 to 0.70, all but one being at least 0.60 (substantial agreement). The overall kappa coefficient kappa for each pathologist compared with the others for Gleason score groups 2-4, 5-6, 7, and 8-10 ranged from 0.47 to 0.64 (moderate-substantial agreement), only one less than 0.50. At least 70% of the urologic pathologists agreed on the Gleason grade group (2-4, 5-6, 7, 8-10) in 38 ("consensus" cases) of the 46 cases. The 8 "nonconsensus" cases included low-grade tumors, tumors with small cribriform proliferations, and tumors whose histology was on the border between Gleason patterns. Interobserver reproducibility of Gleason grading among urologic pathologists is in an acceptable range.

Humans↗

PubMed2003

Inter-laboratory reproducibility of the hand disinfection reference procedure of EN 1500.

Recent tests carried out using EN 1500 have suggested that most alcohol-based hand gels are significantly less effective than the reference alcohol [2-propanol, 60% (v/v)] whereas liquid alcohol-based hand rubs are not. However concerns about the accuracy and reproducibility of the test have been raised. We therefore analysed 41 experiments performed in four different laboratories using EN 1500 hand disinfection procedures with the reference alcohol, to analyse inter-laboratory reproducibility of the test. The mean reduction factors (difference of the log(10) of the pre-value and the post-value) from the four laboratories did not reveal a significant difference (P=0.059; analysis of variance), although the difference of the mean pre and post-values was highly significant (P<0.001). EN 1500 is a reproducible test method which leads to valid data.

Analysis of Variance↗

PubMed2002

The reproducibility of a new dietary record routine in geriatric patients.

BACKGROUND AND AIM: Malnutrition in nursing home residents is an important clinical and public health problem. Knowledge is lacking about the reproducibility of dietary recording in geriatric patients. Few studies have described water intake in this age group. The aim of this study was to test the reproducibility of a 7-day dietary record routine in a clinical setting. METHODS: The dietary intake of 81 geriatric patients was recorded for two discrete periods of 7 consecutive days by the ward staff. The dietary record routine, which assessed both food and fluid intake, was based on standardized portion sizes and household measurements. RESULTS: The mean daily energy intake during the first period was 7.07 MJ and 6.84 MJ during the second period, with a mean difference of 4%. Corresponding values and the mean difference for water intake from food and beverages were 1781 g, 1702 g and 4% respectively. Age, gender, diagnosis, length of stay, diets or ADL function did not influence the results. The correlation coefficient for fluid intake between the periods was 0.84 for women and 0.72 for men. CONCLUSION: The 7-day dietary record routine seems to have a good reproducibility in assessing the intake of energy and fluids in geriatric patients.

Aged↗

PubMed1999

The prognostic value and reproducibility of the radiological features of the fractured scaphoid.

We investigated whether the radiological features of the fractured scaphoid could be reproducibly measured and used to predict the likelihood of union with conservative plaster cast immobilization. We found that the inter- and intra-observer reproducibility of the Compson, Herbert and Russe classification systems were only fair and that none predicted fracture union. Assessments of fracture level, comminution and displacement showed moderate inter- and intra-observer reproducibility but did not predict the likelihood of fracture union. We conclude that the radiological features of acute scaphoid fractures cannot be used to predict the likelihood of fracture union.

Carpal Bones↗

PubMed2004

The reproducibility of perceptually regulated exercise responses during short-term cycle ergometry.

The purpose of this study was to assess the reproducibility over four trials of perceptually regulated exercise intensity during short-term cycle ergometry. Recent research has suggested that an improvement in the reproducibility (better agreement) of the exercise output would be observed with a repeated practice using regulatory tools such as Borg's 6 - 20 rating of perceived exertion (RPE) scale. Eighteen healthy active volunteers (nine males, mean age (+/- SD) 24.7 +/- 3.4 yr, and nine females 27.6 +/- 5.4 yr) completed four identical intermittent effort production trials on a cycle ergometer over a period of two - three weeks, with all trials being between three and five days apart. After warm-up, the volunteers were asked to produce four x three-minute bouts of exercise at RPE levels: 13, 15, 9, and 17 (in this order). Power output (W), percentage maximum heart rate reserve (%MHRR), and oxygen consumption (VO(2); ml x kg(-1) x min(-1)) were recorded in the final minute of each bout. Analysis revealed that the 95 % limits of agreement (LoA) between repeated trials did not decrease for the objective markers of exercise intensity, remaining wide throughout. In the worst case comparisons the LoA represented changes (expressed as a proportion of the mean of two trials) of up to 58.3 % in power output (T2 vs. T3 at RPE 9), 65.5 % in % MHRR (T1 vs. T2 at RPE 13) and 36.5 % in VO(2) (T3 vs. T4 at RPE 17). These findings question the use of ratings of perceived exertion to regulate exercise effort. That the reproducibility of effort is also not seen to improve with practice raises doubts about the validity of using the RPE scale to provide training intensities for this type of exercise.

Adult↗

PubMed2006

Reproducibility of time at or near VO2max during intermittent treadmill running.

The purpose of this study was to determine the reproducibility of time at or above 90 % (t (90 % )VO (2max)) and 95 % (t (95 % )VO (2max)) maximal oxygen uptake during an intermittent treadmill run to exhaustion. Twenty-two distance runners (age 38.0 +/- 7.1 yrs) performed two identical incremental and two identical intermittent tests on four separate days. Respiratory exchange was measured continuously throughout each test by an automated open-circuit gas analysis system. The incremental test consisted of increases in treadmill speed every minute until volitional exhaustion. The highest averaged 30-s oxygen uptake (VO (2)) value was defined as VO (2max) and the minimum speed that elicited VO (2max) was defined as vVO (2max). The intermittent test consisted of 30-s work intervals ran at 105 % vVO (2max) interspersed by 30-s relief intervals ran at 60 % vVO (2max) and was continued until volitional exhaustion. The time that VO (2) was at or above 90 % and 95 % of the mean maximum values elicited during the two previous incremental tests was determined for the intermittent tests. The mean t (95 % )VO (2max) was 232 (SD 174) s and 244 (SD 195) s and the mean t (90 % )VO (2max) was 480 (SD 220) s and 488 (SD 252) s, for trial 1 and trial 2, respectively. Reproducibility statistics for t (95 % )VO (2max) and t (90 % )VO (2max), respectively, were: 95 % limits of agreement 12 +/- 227 s and 8 +/- 328 s; coefficient of variation 34.5 % and 24.5 %; and intraclass correlation coefficient 0.80 and 0.75. Statistical power analysis indicated that this level of reproducibility would allow mean differences of 15 - 20 % between intermittent training protocols to attain statistical significance in future experimental research, with sample sizes probably within the resources of most researchers.

Adult↗

PubMed2006

Reproducibility of a glycemic response to mixed meals in type 2 diabetes mellitus.

OBJECTIVE: To evaluate the inter-patient and intra-patient reproducibility of the glycemic response to a mixed meal in individuals with type 2 diabetes mellitus (DM). SUBJECTS/SETTING: Six individuals with DM were admitted to the General Clinical Research Center for 6 days. INTERVENTION: Subjects consumed 3 different meal plans consisting of 4 meals daily (breakfast, lunch, dinner and snack) on 2 separate occasions. Serum insulin and glucose levels were sampled at 19 time points every day. The glycemic response (GR) to a meal was calculated as the area under the glucose response curve after consumption of a given meal. In addition, the incremental area under the curve (IGR) was calculated assuming a pre-prandial (baseline) glucose value before each meal as zero. RESULTS: Intra-patient correlation coefficients (R) of GR for meals in subjects with DM were quite good, ranging 0.69-0.94. The range of the inter-patient coefficients of variation (CV) for the same meals was 21.5-30.4%. For IGR, the R values ranged from 0.64 to 0.91 for 8 out of 12 meals, confirming good intra-patient reproducibility for these meals. CV for IGR ranged from 31% to 113%. CONCLUSIONS: For patients with DM, the GR of individual meals exhibits excellent intra-patient reproducibility, allowing prediction of the glycemic response to a given meal in an individual subject. However, significant inter-patient variability of the GR precludes its use for the prediction of post-prandial glucose concentrations in groups of patients with diabetes.

Adult↗

PubMed1993

Reproducibility of assessment of left-ventricular function using intraoperative transesophageal echocardiography.

Reproducibility of results is an important point in assessing the utility of intraoperative transesophageal echocardiography for evaluating changes in left-ventricular function. The purpose of the present study was to define the intra- and interobserver reproducibility of the qualitative assessment of left-ventricular regional wall motion and the quantitative assessment of global left-ventricular function. In addition, the interstudy reproducibility of two examinations was tested when the probe was displaced and replaced in the esophagus. A transesophageal short-axis view at the level of the papillary muscles was obtained in 86 patients undergoing cardiac surgery. In the 80 patients with adequate images, regional wall motion was visually graded and area ejection fraction was calculated by two observers and assessment was repeated by the same observer one day later. The same observer graded wall motion differently in only 5% (24/480) of segments. Grading by two observers differed in 9% (43/480) of segments. Assessment differed by one grade at the most and in not more than 2 out of 6 segments per patient. Repeated measurements of area ejection fraction (AEF) by the same observer correlated well (r = 0.97 before and r = 0.97 after cardiopulmonary bypass) with a mean percent difference of 6%. A similarly close correlation was found for measurements of two observers (r = 0.90 and r = 0.93, respectively) with a mean percent difference of 10% for area ejection fraction. The correlation for the first and second examination in the same patient by one observer was acceptable (r = 0.78 and r = 0.80, respectively) with a mean percent difference of 15% for area ejection fraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMedDate not supplied

[Reproducibility in the roentgenological assessment of coxarthritis].

The "German Society of Orthopaedic Surgery and Traumatology (DGOT)" is trying to support the application of standardized and reproducible criteria in diagnosis and therapy of osteoarthritis. As radiographs are a primary measure of outcome at present, the objective of this study was to investigate the reproducibility of radiologic assessment in hip osteoarthritis using different radiographic variables. 3 investigators read 100 hip joints on 50 pelvis radiographs at two time-points for the presence and severity of individual radiographic features: joint space narrowing (JSN), osteophytes, sklerosis, subchondral cysts and deformity of the femoral head. Additionally the summary grade of Kellgren and Lawrence (1963) and Scott et al (1992) was assessed. Intra- and inter-rater-reliability were calculated by intra-class-correlation-co-efficient (ICC). The results regarding intra- and inter-rater-reliability show excellent values for superior JSN, femoral head deformity and the summary score. The radiologic assessment of medial JSN, osteophytes and acetabular sklerosis depends on the level of the investigator's experience. Perifoveal osteophytes and subchondral cysts do not seem to be have sufficient reproducibility. The results of our investigation show, that a reliable radiological classification of the severity of hip osteoarthritis is possible by assessment of certain individual radiographic features or a summary grade.

Adult↗

PubMedDate not supplied

[Reproducibility of radiologic diagnosis in gonarthrosis].

AIM OF STUDY: Ongoing efforts of the "German Society of Orthopaedic Surgery and Traumatology" (DGOT) to standardize diagnosis and therapy of osteoarthritis, necessitated this study, where the reproducibility of different radiographic features of knee-OA was assessed. METHODS: Three readers graded 100 antero-posterior and lateral knee radiographs for selected features (femorotibial osteophytes, joint space narrowing, sclerosis and chondrocalcinosis; patellofemoral osteophytes) and an overall-score (Kellgren and Lawrence, 1963) at two time points 3 months apart. Intra- and inter-observer-reliability were calculated by intra-class correlation-coefficient (ICC). RESULTS: Osteophytes in the femorotibial as well as in the patellofemoral joint could be assessed with a high intra- and inter-observer-reliability. While for joint space narrowing intra-observer-reliability is excellent, the inter-observer-reliability is less satisfactory, and subchondral sclerosis as well as chondrocalcinosis showed even less reproducibility. The Kellgren-Lawrence global score proofed to be highly reproducible. CONCLUSION: Based on the results of this examination, we can recommend a reliable radiographic classification of knee osteoarthritis by grading of relevant individual features (osteophytes and joint space narrowing) and overall assessment.

Follow-Up Studies↗

PubMed1994

[The Heidelberg Retina Tomograph: reproducibility and measuring errors in different pupillary widths using a model eye].

BACKGROUND: We measured the reproducibility and relative error of the Heidelberg Retina Tomograph (HRT) in a model eye with various widths of the pupil. METHODS: We put diaphragms of various diameters in front of the lens of a model eye. The volume of an artificial papilla which was inserted into the model eye was measured three times. The coefficient of variation (standard deviation/mean value) was taken as a measure of the reproducibility. The relative error was defined as the absolute value of the quotient of the difference between measured and real value. RESULTS: The relative error for diaphragms of 1.5 to 5 mm was 7% to 18.4%, for a diaphragm of 1 mm 19.8%, and for a diaphragm of 11 mm 21.3%. The coefficient of variation ranged from 0.49% to 1.95% for diaphragms of 1.5 to 11 mm diameter, and was 8.1 for a diaphragm of 1 mm diameter. CONCLUSION: The HRT is capable of measuring volumes with a reasonable accuracy. The accuracy does not depend on the width of the pupil over a wide range of pupil diameters. In cases of very small or very much dilated pupils the accuracy and reproducibility declines.

Eye, Artificial↗

PubMed1998

The reproducibility of a method to identify the overuse and underuse of medical procedures.

BACKGROUND: To assess the overuse and underuse of medical procedures, various methods have been developed, but their reproducibility has not been evaluated. This study estimates the reproducibility of one commonly used method. METHODS: We performed a parallel, three-way replication of the RAND-University of California at Los Angeles appropriateness method as applied to two medical procedures, coronary revascularization and hysterectomy. Three nine-member multidisciplinary panels of experts were composed for each procedure by stratified random sampling from a list of experts nominated by the relevant specialty societies. Each panel independently rated the same set of clinical scenarios in terms of the appropriateness of the relevant procedure on a risk-benefit scale ranging from 1 to 9. Final ratings were used to classify the procedure in each scenario as necessary or not necessary (to evaluate underuse) and inappropriate or not inappropriate (to evaluate overuse). Reproducibility was measured by overall agreement and by the kappa statistic. The criteria for underuse and overuse derived from these ratings were then applied to real populations of patients who had undergone coronary revascularization or hysterectomy. RESULTS: The rates of agreement among the three coronary-revascularization panels were 95, 94, and 96 percent for inappropriate-use scenarios and 93, 92, and 92 percent for necessary-use scenarios. Agreement among the three hysterectomy panels was 88, 70, and 74 percent for inappropriate-use scenarios. Scenarios involving necessary use of hysterectomy were not assessed. The three-way kappa statistic to detect overuse was 0.52 for coronary revascularization and 0.51 for hysterectomy. The three-way kappa statistic to detect underuse of coronary revascularization was 0.83. Application of individual panels' criteria to real populations of patients resulted in a 100 percent variation in the proportion of cases classified as inappropriate and a 20 percent variation in the proportion of cases classified as necessary. CONCLUSIONS: The appropriateness method is far from perfect. Appropriateness criteria may be useful in comparing levels of appropriate procedures among populations but should not by themselves be used to direct care for individual patients.

Delphi Technique↗

PubMed2004

Many-body force field models based solely on pairwise Coulomb screening do not simultaneously reproduce correct gas-phase and condensed-phase polarizability limits.

It is demonstrated that many-body force field models based solely on pairwise Coulomb screening cannot simultaneously reproduce both gas-phase and condensed-phase polarizability limits. Several many-body force field model forms are tested and compared with basis set-corrected ab initio results for a series of bifurcated water chains. Models are parameterized to reproduce the ab initio polarizability of an isolated water molecule, and pairwise damping functions are set to reproduce the polarizability of a water dimer as a function of dimer separation. When these models are applied to extended water chains, the polarization is over-predicted, and this over-polarization increased as a function of the overlap of molecular orbitals as the chains are compressed. This suggests that polarizable models based solely on pairwise Coulomb screening have some limitations, and that coupling with non-classical many-body effects, in particular exchange terms, may be important.

Artifacts↗

PubMed2001

Subjects with mild and moderate asthma respond to segmental allergen challenge with similar, reproducible, allergen-specific inflammation.

BACKGROUND: The relationship between severity of asthma and bronchial inflammation is poorly understood. OBJECTIVE: We examined acute and subacute inflammatory responses to allergen in subjects with mild and moderate persistent asthma to evaluate whether different cellular and mediator responses to endobronchial allergen challenge are associated with differences in disease severity. METHODS: Segmental allergen challenge was performed in 8 subjects with mild and 10 subjects with moderate allergic asthma to compare baseline airways inflammation and allergen-induced inflammatory responses 24 hours later. This evaluation was repeated after 6 weeks in 9 subjects to investigate the reproducibility of these inflammatory responses. RESULTS: Subjects with mild and moderate asthma had similar decreases in FEV(1) in response to segmental allergen challenge (9.1% +/- 4.2% vs 15.1% +/- 4.6%, P = .35). There was no difference in inflammatory cell counts or cytokine concentrations in the groups with mild and moderate asthma at baseline or after saline or allergen challenge. Repeat segmental allergen challenge 6 weeks later showed that these cellular and cytokine responses were reproducible. CONCLUSION: Segmental allergen challenge in subjects with mild and moderate asthma produces similar allergen-specific physiologic and inflammatory responses that are reproducible 6 weeks later. In this model of allergic asthma, acute responses to allergen do not appear to be related to disease severity.

Adult↗

PubMed2002

Endoscopic assessment of the "Z-line" (squamocolumnar junction) appearance: reproducibility of the ZAP classification among endoscopists.

BACKGROUND: The histologic presence of intestinal metaplasia in the esophagus is a prerequisite for the diagnosis of Barrett's esophagus. Thus, use of the term Barrett's esophagus to describe certain endoscopic features in the distal esophagus is inappropriate. There is no accepted classification system for the endoscopic description of the squamocolumnar mucosal junction, the so-called "Z-line." Furthermore, no clear definition of the normal Z-line exists. A classification of the Z-line appearance has been proposed: the ZAP classification. The aim of this study was to assess the reproducibility of this classification. METHODS: Ten physicians with varying endoscopy experience were presented with 15 endoscopic photographs of the Z-line and were asked to classify them according to the ZAP classification. A second assessment was conducted between 7 and 15 weeks after the first. RESULTS: The median kappa values were in the range of 0.72 to 0.90 with regard to intraobserver as well as interobserver reproducibility, irrespective of experience with upper endoscopy. CONCLUSIONS: The intraobserver and interobserver reproducibility of the ZAP classification is substantial and thus it is feasible to use this classification to characterize the appearance of the Z-line at endoscopy.

Barrett Esophagus↗