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PubMed2004

Temporal precision in the mammalian circadian system: a reliable clock from less reliable neurons.

The mammalian SCN contains a biological clock that drives remarkably precise circadian rhythms in vivo and in vitro. This study asks whether the cycle-to-cycle variability of behavioral rhythms in mice can be attributed to precision of individual circadian pacemakers within the SCN or their interactions. The authors measured the standard deviation of the cycle-to-cycle period from 7-day recordings of running wheel activity, Period1 gene expression in cultured SCN explants, and firing rate patterns of dispersed SCN neurons. Period variability of the intact tissue and animal was lower than single neurons. The median variability of running wheel and Period1 rhythms was less than 40 min per cycle compared to 2.1 h in firing rate rhythms of dispersed SCN neurons. The most precise SCN neuron, with a period deviation of 1.1 h, was 10 times noisier than the most accurate SCN explant (0.1 h) or mouse (0.1 h) but comparable to the least stable explant (2.1 h) and mouse (1.1 h). This variability correlated with intrinsic period in mice and SCN explants but not with single cells. Precision was unrelated to the amplitude of rhythms and did not change significantly with age up to 1 year after birth. Analysis of the serial correlation of cycle-to-cycle period revealed that approximately half of this variability is attributable to noise outside the pacemaker. These results indicate that cell-cell interactions within the SCN reduce pacemaker noise to determine the precision of circadian rhythms in the tissue and in behavior.

Aging↗
PubMed1994

[Goal attainment scaling: reliability and practical experiences with 397 psychiatric treatment courses. Part 1: Evaluation of validity and reliability].

Standardized outcome measures are often criticized, individualized criteria being preferred. Goal attainment scaling (GAS) is such an individual evaluation tool. It aims at measuring, whether a patient attains, what is thought to be his potential. For 36 psychiatric patients outcome estimated by GAS was compared with traditional outcome-measures ("Brief psychiatric rating scale", BPRS, "Clinical global impression", CGI, outcome-scales of Strauss and Carpenter and a patient self-rating. Concurrent validity was sufficient, compared to BPRS, CGI and the scale "absence of symptoms". The other scales of Strauss and Carpenter and the patient self-rating did not correlate closely with GAS. Traditional interraterreliability was sufficient, but if two raters constructed separate scales for one patient, their GAS scores correlated weakly. GAS is recommended for further study in spite of its obvious shortcommings: there seems to be no other way of quantifying, to what degree a patient realized his individual potential.

Activities of Daily Living↗
PubMed1996

The reliability of the functional independence measure: a quantitative review.

OBJECTIVE: The reliability of the Functional Independence Measure (FIMSM) for adults was examined using procedures of meta-analysis. DATA SOURCES: Eleven published studies reporting estimates of reliability for the FIM were located using computer searches of Index Medicus, Psychological Abstracts, the Functional Assessment Information Service, and citation tracking. STUDY SELECTION: Studies were identified and coded based on type of reliability (interrater, test-retest, or equivalence), method of data analysis, size of sample, and training or experience of raters. DATA EXTRACTION: Information from the articles was coded by two independent raters. Interrater reliability for coding all elements included in the analysis ranged from .89 to 1.00. DATA SYNTHESIS: The 11 investigations included a total of 1,568 patients and produced 221 reliability coefficients. The majority of the reliability values (81%) were from interrater reliability studies, and the intraclass correlation coefficient (ICC) was the most commonly used statistical procedure to compute reliability. The reported reliability values were converted to a common correlation metric and aggregated across the 11 studies. The results revealed a median interrater reliability for the total FIM of .95 and median test-retest and equivalence reliability values of .95 and .92, respectively. The median reliability values for the six FIM subscales ranged from .95 for Self-Care to .78 for Social Cognition. For the individual FIM items, median reliability values varied from .90 for Toilet Transfer to .61 for Comprehension. Median and mean reliability coefficients for FIM motor items were generally higher than for items in the cognitive or communication subscales. CONCLUSIONS: Based on the 11 studies examined in this review the FIM demonstrated acceptable reliability across a wide variety of settings, raters, and patients.

Activities of Daily Living↗
PubMed2002

Reliability of self-reported reproductive factors and childhood social class indicators in a case-control study in women.

PURPOSE: Reproductive factors are often evaluated in epidemiologic interview studies as risk factors for diseases in women. Similarly, childhood social class has been implicated in the etiology of several diseases. Nevertheless, questions related to these factors have not been thoroughly evaluated for test-retest reliability. This research measured the test-retest reliability of reproductive and childhood social class variables, and determined whether reliability differed by case-control status, age, educational level, time between interviews, and interviewer-rated quality of the interview. METHODS: Subjects were participants in a population-based case-control in-person interview study of Hodgkin's disease in northern California women. Twenty-four cases and 22 controls were reinterviewed by telephone between 1992 and 1995, with an average interval of 8 months between interviews. Reliability was assessed using kappa or intraclass correlation coefficients; mean reliability coefficients and 95% confidence intervals (CIs) were estimated using the bootstrap method. RESULTS: Reliability was excellent for all variables (reliability coefficients between 0.76 and 0.96) and did not differ by case-control status (mean reliability = 0.82 for cases and 0.84 for controls), age (mean reliability = 0.85 for age < 40 and 0.82 for age > or = 40), time between interviews (mean reliability = 0.75 for 0-5 months, 0.88 for 6-11 months, and 0.87 for 1 year or more), or interviewer-rated quality of the validity of the original responses (mean reliability = 0.93 for "not too confident" and 0.83 for "confident"). However, reliability was consistently lower among less educated women (mean reliability = 0.56 for high school or less and 0.88 for more than high school), a finding consistent with results of prior studies. CONCLUSIONS: These results indicate that questions about reproductive experience and childhood social class posed in in-person interviews can be answered reliably. However, inclusion of subjects at lower socioeconomic status may result in lower reliability for some interview responses.

Adult↗
PubMed2005

Reliability analysis for manual adolescent idiopathic scoliosis measurements.

STUDY DESIGN: Manual radiographic measurement analysis. OBJECTIVES: To determine the intraobserver and interobserver reliability of numerous radiographic process measures used in the assessment of adolescent idiopathic scoliosis. SUMMARY OF BACKGROUND DATA: Analysis of scoliosis requires a thorough radiographic evaluation to completely assess the deformity. Numerous radiographic process measures have been studied extensively and used for outcomes assessment and thus become the de facto standard of care. However, many of these measures have not been evaluated to determine the reliability and reproducibility. Validation of radiographic process measures is necessary to compare these measures with patient-focused outcome measures, as well as to permit valid comparison of different surgical techniques. METHODS: Thirty complete sets of long-cassette scoliosis radiographs (anteroposterior [AP], lateral and side-bending preoperative and AP, and lateral postoperative) were analyzed by three independent experienced observers on two separate occasions. Coronal image measures included the coronal Cobb angles, side-bending Cobb, apical vertebral translation, coronal balance, T1 tilt, lowest instrumented vertebrae (LIV) tilt, angulation of the disc below the LIV, apical vertebral rotation (Nash-Moe),and Risser sign; sagittal measures included T2-T5, T5-T12, T2-T12, T10-L2, T12-S1, and sagittal balance. Intraobserver and interobserver reliability for each measure was then assessed. RESULTS: The vast majority of the radiographic process measures assessed demonstrated good to excellent or excellent intraobserver and interobserver reliability. However, the angulation of the disc below the LIV demonstrated only fair interobserver reliability for postoperative measurements (rho = 0.59). Likewise, Risser grade measurements reflected good intraobserver (0.81-0.99) but only fair interobserver reliability (0.60-0.70). Apical vertebral rotation assessed by the technique of Nash and Moe produced good intraobserver reliability before surgery (0.74-0.85) but only fair reliability after surgery (0.50-0.85). The interobserver reliability for apical Nash-Moe rotation was fair to poor (0.53-0.59). For T2-T5 regional kyphosis, intraobserver (0.22-0.83) and interobserver (0.33-0.47) reliability was generally poor. Overall, the reliability of postoperative measurements tended to be decreased relative to preoperative values, likely due to instrumentation overlying radiographic landmarks. CONCLUSIONS: Most of the radiographic process measures evaluated in this study demonstrated good or excellent reliability. The reliability of measuring the angulation of the disc below the LIV, the apical Nash-Moe rotation, and Risser grading was decreased relative to other measures. The reliability of measuring T2-T5 regional kyphosis was disappointing and poor. With regards to the other 13 measures assessed, our findings support the use of these process measures obtained by experienced deformity surgeons via manual measurement for routine clinical and academic purposes.

Adolescent↗
PubMedDate not supplied

A reliability study for evaluating information extraction from radiology reports.

GOAL: To assess the reliability of a reference standard for an information extraction task. SETTING: Twenty-four physician raters from two sites and two specialties judged whether clinical conditions were present based on reading chest radiograph reports. METHODS: Variance components, generalizability (reliability) coefficients, and the number of expert raters needed to generate a reliable reference standard were estimated. RESULTS: Per-rater reliability averaged across conditions was 0.80 (95% CI, 0.79-0.81). Reliability for the nine individual conditions varied from 0.67 to 0.97, with central line presence and pneumothorax the most reliable, and pleural effusion (excluding CHF) and pneumonia the least reliable. One to two raters were needed to achieve a reliability of 0.70, and six raters, on average, were required to achieve a reliability of 0.95. This was far more reliable than a previously published per-rater reliability of 0.19 for a more complex task. Differences between sites were attributable to changes to the condition definitions. CONCLUSION: In these evaluations, physician raters were able to judge very reliably the presence of clinical conditions based on text reports. Once the reliability of a specific rater is confirmed, it would be possible for that rater to create a reference standard reliable enough to assess aggregate measures on a system. Six raters would be needed to create a reference standard sufficient to assess a system on a case-by-case basis. These results should help evaluators design future information extraction studies for natural language processors and other knowledge-based systems.

Evaluation Studies as Topic↗
PubMed2000

Methodology of a multi-site reliability study. EPSILON Study 3. European Psychiatric Services: Inputs Linked to Outcome Domains and Needs.

BACKGROUND: The European Psychiatric Services: Inputs Linked to Outcome Domains and Needs (EPSILON) Study aims to produce standardised versions in five European languages of instruments measuring needs for care, family or caregiving burden, satisfaction with services, quality of life, and socio-demographic and service receipt. AIMS: To describe background, rationale and design of the reliability study, focusing on reliable instruments, reliability testing theory, a general reliability testing procedure and sample size requirements. METHOD: A strict protocol was developed, consisting of definitions of the specific reliability measures used, the statistical methods used to assess these reliability coefficients, the development of statistical programmes to make inter-centre reliability comparisons, criteria for good reliability, and a general format for the reliability analysis. CONCLUSION: The reliability analyses are based on classical test theory. Reliability measures used are Cronbach's alpha, Cohen's kappa and the intraclass correlation coefficient. Intersite comparisons were extended with a comparison of the standard error of measurement. Criteria for good reliability may need to be adapted for this type of study. The consequences of low reliability, and reliability differing between sites, must be considered before pooling data.

Adult↗
PubMed2000

Prevalence of childhood asthma and allergy in an inner city Malaysian community: intra-observer reliability of two translated international questionnaires.

OBJECTIVES: (a) To examine the intra-observer reliability of the Malay language versions of two international respiratory questionnaires i.e. the International Study of Asthma and Allergy in Children (ISAAC) and the American Thoracic Society (ATS) questionnaires, and (b) using the more reliable of these questionnaires, to estimate the prevalence of asthma and allergy related symptoms in an ethnically homogenous inner city community in Kuala Lumpur. METHODS: The study was conducted among 7 to 12 year old school children of Malay ethnic origin living in an inner city area of Kuala Lumpur. The sample consisted of 787 children attending the only primary school in the area. The Malay versions of both questionnaires were administered twice, one month apart, and were completed by parents. Agreement between the first and second responses to the same questions were assessed by Cohen's kappa. Kappa values < 0.4 were indicative of poor intra-observer reliability, 0.4-0.59 moderate reliability, 0.6-0.79 good reliability and > 0.79 excellent reliability. RESULTS: 77.9% and 36.3% of parents responded to the first and second administrations of the questionnaires respectively. Kappa values of > 0.4 were obtained in 15/16 (93.8%) and 17/27 (63.0%) questions of the ISAAC and ATS questionnaires respectively. Excellent kappa values were obtained in 4/16 (25%) questions of the ISAAC questionnaire versus only 1/27 (3.7%) questions of the ATS questionnaire. From the ISAAC questionnaire, all questions on wheeze had good reliability while those on asthma had excellent reliability. Questions on allergic symptoms had poor to moderate reliability. In contrast, from the ATS questionnaire, questions on wheeze had moderate reliability while questions on asthma were excellently reliable. Questions on allergic symptoms had moderate to good reliability while those on cough, phlegm and bronchitis had poor reliability. According to the ISAAC questionnaire the prevalence of ever wheeze, wheeze in the last 12 months, ever asthma and wheeze with exercise in the last 12 months was 12.5%, 6.6%, 10.3% and 5.9% respectively. The prevalence of ever sneeze or runny nose, sneeze or runny nose in the last 12 months, watery eyes in the last 12 months and ever eczema was 15.2%, 11.1%, 4.4% and 8.5% respectively. CONCLUSIONS: The translated ISAAC questionnaire was more reliable than the translated ATS questionnaire. Asthma and related symptoms were common among Malay school children in inner city Kuala Lumpur.

Asthma↗