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PubMedDate not supplied

[Comparative evaluation of a German version of the Health Assessment Questionnaire and the Hannover Functional Capacity Questionnaire].

OBJECTIVE: To translate the Health Assessment Questionnaire Disability Index (HAQ) into a German version, to validate and to compare its properties with two different versions of the Hannover Functional Ability Questionnaire (HFAQ) in a German speaking population. METHODS: The test-retest reliability was tested by Pearson correlation in 32 outpatients of the Department of Rheumatology of the Medizinische Hochschule Hannover. For retesting, the questionnaire was mailed to them 1 week later. To validate the questionnaire it was administered to 110 inpatients in three different hospitals. All patients fulfilled the American College of Rheumatology 1987 revised criteria of rheumatoid arthritis (RA) or the Rome criteria of definitive inactive RA. The internal consistency was measured by Cronbach's coefficient alpha (CCA). To assess criterion validity we compared the HAQ and the two versions of the HFAQ with Keitel's test (KT) and the modified Steinbrocker classification (mSC). Construct validity was assessed by comparing these instruments with different clinical and laboratory variables. A multivariate analysis was used to identify the most important factors that are influencing the HAQ- and HFAQ-scores. RESULTS: Test-retest reliability of the HAQ was r = 0.94. CCA was 0.91 (HAQ), 0.90 (HFAQ-P) and 0.93 (HFAQ-PR). The KT Pearson correlation coefficients reached r = -0.73 (HAQ), r = +0.74 (HFAQ-P) and r = +0.71 (HFAQ-PR). The mSC correlated r = +0.75 (HAQ), r = -0.72 (HFAQ-P) and r = -0.70 (HFAQ-PR). The correlation coefficients of HAQ/HFAQ-P was r = -0.87 and of HAQ/HFAQ-PR r = -0.88. The correlations between other clinical and laboratory variables reached from r = +/-0.58 (pain/HAQ) to r = +/-0.11 (number of swollen joints/HFAQ-PR). In backward multiple regression analysis 59-64% of the variance of disability measured by the questionnaires was explained predominantly by pain (32-33%) and by range of motion (16-21%). CONCLUSION: The German version of the HAQ presented here and the two versions of the HFAQ are reliable and valid instruments for measuring functional disability in a German-speaking population with RA. The construct measured by the HAQ and both versions of the HFAQ showed a high degree of correspondence.

Activities of Daily Living↗
PubMed1995

ASHP therapeutic position statement on the use of the International Normalized Ratio system to monitor oral anticoagulant therapy.

The INR system of standardizing PT measurements can minimize variability between laboratories, PT reagents, and instruments. The INR system can also facilitate international agreement on therapeutic ranges and allow direct comparison of clinical trials. This should provide greater uniformity in the management of oral anticoagulant therapy and ultimately may improve patient outcomes. ASHP supports the use of the INR system on the basis of studies demonstrating that this system permits warfarin dosing that is less dependent on the variability of thromboplastin reagent sensitivity.

Administration, Oral↗
PubMed2004

Correlated measurement error--implications for nutritional epidemiology.

BACKGROUND: In nutritional epidemiology, it is common to fit models in which several dietary variables are included. However, with standard instruments for dietary assessment, not only are the intakes of many nutrients often highly correlated, but the errors in the estimation of the intake of different nutrients are also correlated. The effect of this error correlation on the results of observational studies has been little investigated. This paper describes the effect on multivariate regression coefficients of different levels of correlation, both between the variables themselves and between the errors of estimation of these variables. METHODS: Using a simple model for the multivariate error structure, we examine the effect on the estimates of bivariate linear regression coefficients of (1) differential precision of measurement of the two independent variables, (2) differing levels of correlation between the true values of the two variables, and (3) differing levels of correlation between the errors of measurement of the two variables. As an example, the prediction of plasma vitamin C levels by dietary intake variables is considered, using data from the European Prospective Investigation of Cancer (EPIC) Norfolk study in which dietary intake was estimated using both a food frequency questionnaire (FFQ) and a 7-day diary (7DD). The dietary variables considered are vitamin C, fat, and energy, with different approaches taken to energy adjustment. RESULTS: When the error correlation is zero, the estimates of the bivariate regression coefficients reflect the precision of measurement of the two variables and mutual confounding. The sum of the observed regression coefficients is biased towards the null as in univariate regression. When the error correlation is non-zero but below about 0.7, the effect is minor. However, as the error correlation increases beyond 0.8 the effect becomes large and highly dependent on the relative precision with which the two variables are measured. At the extreme, the bivariate estimates can become indefinitely large. In the example, the error correlation between fat and energy using the FFQ appears to be over 0.9, the corresponding value for the 7DD being approximately 0.85. The error correlation between vitamin C and fat, and vitamin C and energy, appears to be below 0.5 and smaller for the 7DD than for the FFQ. The impact of these error correlations on bivariate regression coefficients is large. The effect of energy adjustment differs widely between vitamin C and fat. CONCLUSION: High levels of error correlation can have a large effect on bivariate regression estimates, varying widely depending on which two variables are considered. In particular, the effect of energy adjustment will vary widely. For vitamin C, the effect of energy adjustment appears negligible, whereas for fat the effect is large indicating that error correlation close to one can partially remove regression dilution due to measurement error. If, for fat intake, energy adjustment is performed by using energy density, the partial removal of regression dilution is achieved at the expense of substantial reduction in the true variance.

Ascorbic Acid↗
PubMedDate not supplied

A self-administered version of a brief measure of suffering: first aspects of validity.

BACKGROUND: Measuring the impact of illness is important for several reasons. Recently, a new instrument was introduced using a pictorial approach in measuring the perception of suffering caused by illness: the Pictorial Representation of Illness Measure (PRISM). The aim of the present study was to introduce a self-administered version of PRISM and to provide some first data on its validity. METHOD: A postal survey was conducted in subjects with the chronic depigmentation disorder vitiligo. Participants were members of the German vitiligo association. The response rate was 60.6%. Data of 333 respondents completing the PRISM were used for analysis. Besides illness-related measures, psychological variables were assessed with the following instruments: Satisfaction with Life Scale (SWLS), five-item version of the Mental Health Inventory, adaptation of the Skindex-29, a quality-of-life measure for skin diseases. RESULTS: Only 2.9% did not fill in the PRISM. Self-illness separation correlated as predicted with some illness-related variables. The distance was significantly larger in subjects whose depigmentation was no longer spreading. Significant correlations were also found with mental health (0.50), satisfaction with life (-0.28), perceived impairment of outward appearance (-0.65), and the Skindex subscales 'emotions' (-0.66) and 'functioning' (-0.67). CONCLUSION: Data suggest that PRISM can be self-administered. Measures of convergent validity confirm the usefulness of the new measure.

Adult↗
PubMed1982

Physical work capacity and classroom attention of handicapped and non-handicapped children.

The relationship between Physical Work Capacity (PWC) and 'attention in the classroom' was examined using a differential design, with 15 handicapped (age range 94-167 months) and 20 non-handicapped children (age range 91-141 months). The PWC was measured with the aid of a bicycle ergometer and the childrens' attention by means of an observation instrument developed for the purpose. On both variables the non-handicapped children differed significantly from the handicapped children. A low, non-significant relationship was found between scores obtained from the observaton instrument and a teachers' questionnaire for classroom attentional behaviour. The correlation between PWC and 'attention in the classroom' within the two groups was found to be non-significant but different in sign. This suggested relationship betwen PWC and attention merits further study. Suggestions are made with respect to physical training programmes for handicapped children.

Attention↗
PubMed2003

Interlaboratory study for the polychlorinated naphthalenes (PCNs): phase 1 results.

An interlaboratory study was initiated to investigate consistency in reported concentrations of polychlorinated naphthalenes (PCNs). Results are reported from the first phase of a study that examined the variability associated with different quantification methodologies, instrumentation and standards. Nine participating labs from seven countries quantified individual homolog groups, summation operator PCN (the sum of 2-8 chlorinated homologs), and selected congeners in two test solutions derived from Halowax 1014. The means of the reported summation operator PCN values were within less than 15% of the known concentrations of the two test solutions and the relative standard deviation among laboratories was 11%. However, the among laboratory variability was in the range 20-40% for individual PCN homologs and individual PCN congeners. These results suggest the need for additional interlaboratory studies and for the development of reference materials for PCN analysis. Future PCN interlaboratory comparison exercises are discussed that will utilize control materials and unknowns consisting of suitable environmental matrices.

Chlorine Compounds↗
PubMed1997

Failed trial of vacuum or forceps--maternal and fetal outcome.

OBJECTIVE: Our purpose was to compare the maternal and neonatal morbidity associated with a failed trial of instrumental delivery with that of proceeding directly to cesarean section during the second stage of labor. STUDY DESIGN: All second-stage cesarean deliveries between January 1986 and December 1992 in a tertiary care teaching hospital were retrospectively reviewed. Specific maternal and neonatal outcome parameters were studied to compare the failed instrumental group with the direct-to-cesarean section group. RESULTS: Of 29,457 live births at > 37 weeks' gestation, 401 women had a cesarean section performed in the second stage of labor. There were 326 cases in which cesarean section was performed directly during the second stage of labor and 75 women who had a failed attempt of instrumental delivery (forceps 33, vacuum 25, both 17) before cesarean delivery was done. The three instrumental groups and the direct-to-cesarean section group did not differ in any of the outcome variables for either mother or newborn. CONCLUSIONS: Failed instrumental delivery performed as a trial of forceps and/or vacuum in a setting where a cesarean section can follow promptly is not associated with increased morbidity of either mother or baby.

Cesarean Section↗
PubMed1998

Correlates of health-related quality of life in upper aerodigestive tract cancer patients.

Reflecting a limited understanding of the definition and determinants of health-related quality of life (HRQoL), the majority of research in this field has concentrated upon the effect of disease- and treatment-related variables. That work specifically investigating HRQoL among upper aerodigestive tract (UADT) cancer patients is no exception to this observation. Treating subject-related and non-subject-related variables separately, the aim of this study was to investigate predictors of global HRQoL rating in a sample of UADT cancer patients, concentrating upon the relative importance of sociodemographic and clinical variables. A cross-sectional study design was used with a sample of 188 UADT cancer patients. Global HRQoL was assessed using the EORTC QLQ-C30 instrument, global domain (global QoL). Other study variables were collected by subject interview and chart review. Two multivariate regression models were independently developed, containing, respectively, subject-rated and non-subject rated variables. In the model containing subject-rated predictors of global QoL, emotional, breathing, physical, financial, pain and appetite problems were significant predictors (F = 14.6, p < 0.0001 and r2 = 0.54). Among non-subject-rated sociodemographic and clinical variables tested, unemployment, older age, female gender, being dentate and a more advanced disease stage predicted worse global QoL rating, while oral as opposed to pharyngeal or laryngeal cancer predicted a better global QoL rating (F = 5.1, p < 0.0001 and r2 = 0.21). In the latter model, a greater proportion of the variance was explained by sociodemographic variables than by clinical variables.

Adult↗
PubMed1998

The association between chronic illness and functional change among participants in a comprehensive geriatric assessment program.

OBJECTIVE: To examine the association between chronic illness and functional status change during a 3-year period in older people enrolled in an in-home comprehensive geriatric assessment (CGA) and preventive care program. DESIGN: Secondary analysis of data from a longitudinal cohort study. SETTING: Santa Monica, California. PARTICIPANTS: Two hundred two community-dwelling older persons (mean age at baseline was 81 years, 70% were women, and 72% reported good health) randomized to the intervention group in a trial of in-home comprehensive geriatric assessment and preventive care. MEASUREMENTS: We studied 13 common chronic illnesses/conditions determined clinically from an annual comprehensive evaluation by gerontologic nurse practitioners (GNPs) in consultation with study geriatricians. These target conditions included hypertension, osteoarthritis, coronary artery disease, obesity, undernutrition, urinary incontinence, sleep disorders, falls, gait/balance disorders, hearing and vision deficits, depression, and unsafe home environment. The dependent variable was functional change as measured by instrumental activities of daily living (IADL) and basic activities of daily living (BADL) assessed at baseline and annually for 3 years by independent research personnel. Potential confounding variables, including comorbid conditions and other subject characteristics, were controlled for in the analyses. RESULTS: Although functional status was similar at baseline, the presence of certain target conditions in this sample was associated significantly with functional decline in IADL and BADL during the 3-year period. Four conditions (gait/balance disorders, depression, unsafe home environment, and coronary artery disease) were associated with significant declines in IADL, and four conditions (gait/balance disorders, depression, hypertension, and urinary incontinence) were associated with significant declines in BADL. Conversely, subjects with obesity had no significant change in IADL or BADL throughout the study period and had less decline in IADL compared with nonobese subjects. CONCLUSIONS: Certain chronic conditions, particularly gait/balance disorders and depression, are associated with significant decline in functional status in older persons who receive CGA. These findings may help identify older persons at risk for greatest functional decline despite participation in CGA and may also suggest the need for more effective intervention strategies in these individuals.

Activities of Daily Living↗
PubMed1990

A test of fine finger dexterity.

The lack of instruments available for the measurement of fine dexterity (i.e., speed of interdigital manipulation) implies a gap not only in the occupational therapist's ability to quantify and deal precisely with patients' problems in this area, but also in the knowledge base of occupational therapy itself. The Rosenbusch Test of Finger Dexterity (developed by Doris F. Rosenbusch, MA, OTR), a new instrument that measures the speed of interdigital manipulation of objects by each hand separately, was tested on 64 subjects with normal hand function and 10 subjects known to have disabilities affecting fine dexterity. The determination of significant differences by the subjects' sex, dominant and nondominant hands, and normal and dysfunctional hands was performed with t tests. The scores of the subjects with normal hand function versus those with disabled hand function were then compared on all variables. The findings demonstrate that this instrument is ready to be used experimentally and compares favorably with current commercial tests on both reliability and validity coefficients.

Adult↗
PubMed1982

Cardiovascular variability and introversion/extroversion, neuroticism and psychoticism.

Forty-eight subjects were measured during a 10 min rest period for pulse wave velocity (PWV) and heart rate (HR) level and variability, using a Cyborg BL 907 instrument. These subjects were also evaluated by means of the Eysenck Personality Questionnaire for I-E, N, P and L. These data were factor analyzed. Five factors were identified which were accounted for 80.6% of the variance. These factors were: 'cardiovascular lability', 'heart rate time trends', 'cardiovascular balance', 'sex effects' and 'self reports'. The EPQ measurements separated from the physiological measurements in the factor analysis and none were found to be significantly loaded on any physiological variables. On the other hand, significant physiological correlations were found with N. This study adds a possible blood pressure and heart rate descripter to N.

Blood Pressure↗
PubMed2006

Evaluating instruments for a study on children's responses to a painful procedure when parents are distraction coaches.

Existing research identifies numerous variables that may influence children's distress responses during medical procedures. In preparation for a large multisite study to test relationships among these numerous variables and parent distraction coaching, a pilot study of instruments was performed that measured the more complex constructs, namely anxiety, coping, temperament, attention, and parenting style. This article describes the benefits, process, and results of evaluating research instruments before initiating a large study on children's distress during ;medical procedures. A convenience sample of 68 children (4-12 years old) and their parents participated in this study. Children completed state and trait anxiety measures and a coping style scale. Parents completed questionnaires about their child's temperament, attention behavior, anxiety, and coping during a recent medical procedure, and about their own anxiety and parenting style. Coefficients of reliability of the measures were examined and understandability of the instruments was assessed. A forward regression showed that nurturing parenting style, parent's state anxiety, and child's state anxiety accounted for 32% of the variance in child distress during a recent medical procedure.

Attention↗
PubMed1995

Reducing random measurement error in assessing postural load on the back in epidemiologic surveys.

OBJECTIVES: The goal of this study was to design strategies to assess postural load on the back in occupational epidemiology by taking into account the reliability of measurement methods and the variability of exposure among the workers under study. METHODS: Intermethod reliability studies were evaluated to estimate the systematic bias (accuracy) and random measurement error (precision) of various methods to assess postural load on the back. Intramethod reliability studies were reviewed to estimate random variability of back load over time. RESULTS: Intermethod surveys have shown that questionnaires have a moderate reliability for gross activities such as sitting, whereas duration of trunk flexion and rotation should be assessed by observation methods or inclinometers. Intramethod surveys indicate that exposure variability can markedly affect the reliability of estimates of back load if the estimates are based upon a single measurement over a certain time period. Equations have been presented to evaluate various study designs according to the reliability of the measurement method, the optimum allocation of the number of repeated measurements per subject, and the number of subjects in the study. CONCLUSION: Prior to a large epidemiologic study, an exposure-oriented survey should be conducted to evaluate the performance of measurement instruments and to estimate sources of variability for back load. The strategy for assessing back load can be optimized by balancing the number of workers under study and the number of repeated measurements per worker.

Analysis of Variance↗
PubMed1994

Flow cytometric reticulocyte analysis. Multiinstitutional interlaboratory correlation study.

Reticulocyte analysis by flow cytometry offers precision and sensitivity greater than those of conventional morphologic methods and permits derivation of a reticulocyte maturity index. However, interlaboratory variability has not yet been reported. The authors analyzed 310 samples at eight sites using 11 instruments over a 4-month period to examine intermethod and interlaboratory variabilities. Stains included thiazole orange, ethidium bromide, and auramine O. Instruments included models by Coulter, Becton Dickinson, TOA Medical Electronics, and Ortho Diagnostics. The coefficient of variation (CV) among all sites and methods on these samples varied as a function of the reticulocyte percentage, ranging from a mean CV of 69% for samples with < .5% reticulocytes to 24.1% for those with > 2.5% reticulocytes. The best performance was observed with the TOA R-1000 dedicated reticulocyte analyzers, with a mean CV of 18.4% for samples with < .5% reticulocytes and 4.6% for samples with > 2.5% reticulocytes. The reticulocyte maturity index showed comparable intersite precision, with a mean CV of 16% for samples with > 2.5% reticulocytes with multipurpose flow cytometers and a mean CV of 7.3% with the TOA R-1000 instruments. Interclass correlations among all sites ranged from .79 to .99 for the reticulocyte counts and .41 to .88 for the reticulocyte maturity index. The authors conclude that flow cytometric reticulocyte analysis is more precise than manual reticulocyte analysis. With greater automation of this methodology, further interlaboratory standardization of reticulocyte counts and the reticulocyte maturity index can be achieved.

Adolescent↗
PubMed2001

A psychometric analysis of the Quality of Life-Cancer Survivors (QOL-CS) in survivors of childhood cancer.

Given the increasing interest in quality of life research in cancer survivorship, psychometric properties of the Quality of Life-Cancer Survivors (QOL-CS) were explored in a group of childhood cancer survivors. The QOL-CS is a 41-item visual analog scale composed of four multi-item sub-scales (physical well-being, psychological well-being, social well-being, spiritual well-being) and two sub-components (fears, distress). This instrument was incorporated in a mailed survey completed by 177 respondents. The underlying factor structure and internal reliability of the instrument were explored. A preliminary assessment of the external validity of the factor structure was undertaken. Results of a factor analysis were theoretically consistent with elements assessed in the QOL-CS, although misclassification of several items was noted and discussed. Internal-consistency reliability was very good (Cronbach's alpha = 0.80-0.89) for five of the six factors. Moderate (0.30 < r < 0.45) to high (r > 0.60) concurrent validity was observed for four factors. Discriminant validity was noted across groups defined by health and social status variables. Psychometric analysis indicated that the instrument measured distinct and relevant domains of quality of life for childhood cancer survivors, but in its current form does not appear to be an optimal measure of quality of life in this population.

Adolescent↗
PubMed1988

The psychopathology instrument for mentally retarded adults: psychometric characteristics, factor structure, and relationship to subject characteristics.

The self-report and a modified informant version of the Psychopathology Instrument for Mentally Retarded Adults (PIMRA) was used to assess 160 mentally retarded adults. Statistics relating to the instrument's internal consistency and test-retest reliability were calculated. The effects of demographic variables were analyzed and the factor structure of the instrument was examined. Of the psychometric statistics examined, only the item-total correlations were as robust as in the original reports. Significant relationships between PIMRA scores and age, sex, and level of mental retardation were found, but there was no significant effect due to residential setting (institution versus community). The factor structure for both versions of the PIMRA was similar to that in the initial reports.

Adolescent↗
PubMedDate not supplied

Some variables to consider to avoid the need for LASIK surgical enhancements.

BACKGROUND: The predictability of LASIK refractive surgery is important both to the patient and the surgeon in obtaining an optimal result and in reducing the need for enhancement surgery. Some instruments, large ablation zones and possibly other variables may increase hyperopic overcorrection. METHODS: A retrospective study was undertaken of 345 myopic LASIK eyes (175 patients) treated with a Nidek EC-5000. The need for additional surgery in the form of an enhancement was determined after the patient had a stable refraction. The variables measured in the study were the patient's refractive correction, corneal curvature using an Alcon EH-290 topographer, the patient's age and Nidek excimer laser ablation optic and transition zone size. The same nomogram was used for all eyes and where possible bilateral surgery was conducted on all patients. The effect of ablation sizes, refractive errors, patient age and corneal curvature on the enhancement surgeries was evaluated using SPSS 6.0. RESULTS: The most significant variable that precipitated a LASIK enhancement was an optic zone of 6.5 mm with a transition zone of 7.5 mm (paired t-test, p < 0.0025). Multivariate analysis indicates that the older the patient and the larger the refractive error, the greater the risk of not achieving a residual refractive error of +/- 0.50 D at three months. The steeper pre-operative corneas have a greater chance of enhancement (mean of sample 44.48 +/- 1.47 D and mean of enhancements 45.30 +/- 1.65 D, p = 0.01, independent sample test). The smaller optic zone was associated with a smaller refractive over-refraction after LASIK surgery (mean for 5.5 mm optic zone, +0.71 +/- 0.29 D; mean, for 6.5 mm optic +1.27 +/- 0.50 D, paired t-test p < 0.0001). CONCLUSIONS: In this study, the 5.5 mm optic zone appears to dampen or reduce the undesirable refractive results. The optic zone size of choice with the Nidek EC-5000 laser should be 5.5 mm if the patient has small pupils and steep corneas. In this sample, the targeted emmetropic refractive state (range plano to +0.50 D sphere and plano to -0.50 D cylinder) was achieved in 93.3 per cent of cases after three months.

Journal Article↗
PubMed1989

A portable scanning reflectance spectrophotometer using visible wavelengths for the rapid measurement of skin pigments.

A portable rapid scan reflectance spectrometer (400-700 nm in 2.8 s) has been developed for the measurement of cutaneous pigments. The instrument incorporates a tungsten halogen lamp light source, light transmission by fibre optics and wavelength selection by a circular variable wavelength interference filter. A microcomputer controls the instrument and processes the data. The performance of the instrument was evaluated by undertaking in vitro measurements of the reflectance spectra of blood. An index of the haemoglobin content of the sample based on the gradients of the log inverse reflectance spectrum between isobestic points at 527.5, 544 and 573 nm was devised and shown to be independent of the oxygenation of the haemoglobin. The haemoglobin index was combined with measurements at 558.5 nm, a wavelength at which absorbance is sensitive to the oxygenation of haemoglobin, to give a measure of oxygen saturation. The parameter was validated by determining the oxygen dissociation curve of red cells in plasma in vitro at pH 7.33, 37 degrees C and under a partial pressure of 40 mmHg of CO2.

Erythrocytes↗