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PubMed1990

Coma scales in pediatric practice.

Interobserver variability for six coma scales was assessed prospectively on a sample of 15 comatose children, by two physicians, in a double-blind fashion. The six scales were the Glasgow Coma Scale, the Simpson and Reilly Scale, the Children's Coma Score, the Children's Orthopedic Hospital and Medical Center Scale, the Jacobi Scale, and the 0 to IV Scale. Interobserver variability was measured by using disagreement rate and the kappa statistic. The results from both methods were generally concordant. The disagreement rate for the various items in the different scales ranged from a high of 0.20 to a low of 0.03. The disagreement rate was greater than 0.10 for verbal responses in the Children's Coma Score and Glasgow Coma Scale and for both items in the Children's Orthopedic Hospital and Medical Center Scale. The disagreement rate was 0.10 or less for the 0 to IV Scale and for all items in the Simpson and Reilly and Jacobi scales. The relatively high interobserver agreement for these scales makes them more suitable for the pediatric setting than the other three scales, since good agreement is essential for interpreting data reliably, both in clinical practice and for research.

Adolescent↗
PubMed2005

Assessing DSM-IV nicotine withdrawal symptoms: a comparison and evaluation of five different scales.

OBJECTIVE: This study evaluated four of the major scales used to measure nicotine withdrawal symptoms plus one new scale. METHODS: Eighty-three smokers were randomly assigned to continue smoking (n=37) or abstain completely for 24 h (n=46), by which time the symptoms should become manifest. Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) withdrawal symptoms (irritability, depression, restlessness, insomnia, anxiety, hunger and poor concentration) plus craving were measured at baseline and after 24 h. The scales tested were the Minnesota Nicotine Withdrawal Scale (MNWS), the Mood and Physical Symptoms Scale (MPSS), the Shiffman Scale (SS), the Wisconsin Smoking Withdrawal Scale (WSWS) and the newly developed Cigarette Withdrawal Scale (CWS). RESULTS: Measurement of withdrawal symptoms was robust in the case of all scales for total withdrawal score, irritability, restlessness, poor concentration and craving. The MNWS and CWS were less sensitive to depression; the WSWS and MNWS were less sensitive to insomnia; the MPSS was less sensitive to anxiety and hunger; the CWS and WSWS did not include restlessness as a distinct symptom; the SS did not include insomnia, and its scores tended to decline over time during ad lib smoking. Longer scales, using multiple items to measure each symptom, did not yield more reliable or accurate measurement than briefer scales. CONCLUSIONS: To measure total withdrawal discomfort or craving, all of the scales examined can be recommended, and there is little to choose between them apart from length. When it comes to assessing individual symptoms, different scales have different strengths and weaknesses. There would be merits in developing a new questionnaire that combined the best features of the scales tested.

Adolescent↗
PubMed2004

Scale-dependent relationships between the spatial distribution of a limiting resource and plant species diversity in an African grassland ecosystem.

One cornerstone of ecological theory is that nutrient availability limits the number of species that can inhabit a community. However, the relationship between the spatial distribution of limiting nutrients and species diversity is not well established because there is no single scale appropriate for measuring variation in resource distribution. Instead, the correct scale for analyzing resource variation depends on the range of species sizes within the community. To quantify the relationship between nutrient distribution and plant species diversity, we measured NO(3)(-) distribution and plant species diversity in 16 paired, modified Whittaker grassland plots in Serengeti National Park, Tanzania. Semivariograms were used to quantify the spatial structure of NO(3)(-) from scales of 0.4-26 m. Plant species diversity (Shannon-Weiner diversity index; H ') was quantified in 1-m(2) plots, while plant species richness was measured at multiple spatial scales between 1 and 1000 m(2). Small-scale variation in NO(3)(-) (<0.4 m) was positively correlated with 1-m(2) H ', while 1000-m(2) species richness was a log-normal function of average NO(3)(-) patch size. Nine of the 16 grassland plots had a fractal (self-similar across scales) NO(3)(-) spatial distribution; of the nine fractal plots, five were adjacent to plots that had a non-fractal distribution of NO(3)(-). This finding offered the unique opportunity to test predictions of Ritchie and Olff (1999): when the spatial distribution of limiting resources is fractal, communities should display a left-skewed log-size distribution and a log-normal relationship between net primary production and species richness. These predictions were supported by comparisons of plant size distributions and biomass-richness relationships in paired plots, one with a fractal and one with a non-fractal distribution of NO(3)(-). In addition, fractal plots had greater large-scale richness than paired non-fractal plots (1,0-1000 m(2)), but neither species diversity ( H') nor richness was significantly different at small scales (1 m(2)). This result is most likely explained by differences in the scale of resource variation among plots: fractal and non-fractal plots had equivalent NO(3)(-) variation at small scales but differed in NO(3)(-) variation at large scales (as measured by the fractal dimension). We propose that small-scale variation in NO(3)(-) is largely due to the direct effects of plants on soil, while patterns of species richness at large scales is controlled by the patch size and fractal dimension of NO(3)(-) in the landscape. This study provides an important empirical step in understanding the relationship between the spatial distribution of resources and patterns of species diversity across multiple spatial scales.

Africa↗
PubMed2006

Sampling scale effects in random fields and implications for environmental monitoring.

The concept of a sampling scale triplet of spacing, extent and support is used to define the spatial dimensions of a monitoring network or a field study. The spacing is the average distance between samples, the extent is the size of the domain sampled and the support is the averaging area of one sample. The aim of this paper is to examine what is the bias and the random error (uncertainty) introduced by the sampling scale triplet into estimates of the mean, the spatial variance and the integral scale of a variable in a landscape. The integral scale is a measure of the average distance over which a variable is correlated in space. A large number of two dimensional random fields are generated from which hypothetical samples, conforming to a certain sampling scale triplet, are drawn which in turn are used to estimate the sample mean, spatial variance and integral scale. The results indicate that the biases can be up to two orders of magnitude. The bias of the integral scale is positively related to the magnitude of any of the components of the scale triplet while the bias of the spatial variance is different for different components of the scale triplet. All sampling scale effects are relative to the underlying correlation length of the variable of interest which is closely related to the integral scale. The integral scale can hence be used for sampling design and data interpretation. Suggestions are given on how to adjust a monitoring network to the scales of the variables of interest and how to interpret sampling scale effects in environmental data.

Data Collection↗
PubMed1996

A new analogue scale for assessing children's pain: an initial validation study.

A new instrument was designed to provide a practical clinical measure for assessing children's pain intensity and pain affect. The pocket size measure includes a Coloured Analogue Scale (CAS) to assess intensity and a facial affective scale to assess the aversive component of pain. Both scales have numerical ratings on the back, so that the person administering it can quickly note the numbers that represent a child's pain. This study was conducted to determine the validity of the new instrument by evaluating the psychophysical properties of the intensity scale and by evaluating the discriminant validity of the intensity and affective scales. Since visual analogue scales (VAS) are valid and reliable measures for assessing children's pain, children's ability to use the new analog scale was compared with their performance on a VAS. Children's ability to rate pain affect using an affective scale, in which the 9 faces on a Facial Affective Scale (FAS) are presented in an ordered sequence from least to most distressed, was compared to their performance on the original FAS, in which the same faces were presented in a random order. Using a parallel groups design, 104 children (5-16 years; 60 female, 44 male; 51 healthy and 53 with recurrent headaches) were randomized into two groups: CAS or VAS. Children used the assigned scale to complete a calibration task, in which they rated the sizes of 7 circles varying in area (491, 804, 1385, 2923, 3848, 5675 and 7854 mm2). The psychophysical function relating perceived circle size to actual physical size was determined for the CAS and VAS. Children's CAS and VAS responses on the calibration task yielded similar mathematical relationships: psi cas = 0.035I0.87, psi vas = 0.027I0.89, where psi = perceived magnitude and I = stimulus intensity. The R2 values were 0.921 and 0.922 for the CAS and VAS groups, respectively. Analyses of covariance revealed no significant differences in the characteristics of these relationships, i.e., R2, slope, or y intercept, by scale type. Children used the same scale to complete the Children's Pain Inventory (CPI), in which they rated the intensity and affect of 16 painful events (varying in nature and extent of tissue damage). Children's CAS and VAS responses on the CPI were similar. Analyses of covariance indicated that there were no differences in either intensity or affective ratings by scale type. However, the mean number of painful events experienced by children increased significantly with age (P = 0.0001). Intensity ratings decreased significantly with age (P = 0.002), but affective ratings did not vary with age. The new instrument has equivalent psychometric properties to a 165 mm VAS. However, the CAS was rated as easier to administer and score than the VAS, so it may be more practical for routine clinical use. Since the CAS has fulfilled the first two criteria for a pain measure (psychophysical properties and discriminant validity), it is ethical to proceed with the formal definitive test for construct validity, in which children from various clinical populations use the CAS scale to assess their own pain.

Adolescent↗
PubMed1996

Parent-completed scales for measuring seizure severity and severity of side-effects of antiepileptic drugs in childhood epilepsy: development and psychometric analysis.

We have developed two outcome measures for childhood epilepsy: a seizure severity (SS) scale and a side-effects (SE) scale. Both scales have been designed for completion by parents. The scales were tested in two pilot phases and the results of this stepwise analysis are described here. The final scales' psychometric properties were assessed in a group of 80 children with active epilepsy, representative of the population at whom the scales were aimed: children with chronic epilepsy, aged 4-16 years, including all seizure types and epilepsies, as well as children with neurological comorbidity. The SS scale and SE scale showed good internal consistency and test-retest stability. Although there was a significant positive correlation between the SS scale and the SE scale, this was low, indicating that the scales measure a different clinical trait. The SE scale consisted of two subscales: a Toxic subscale, measuring the severity of dose-related side-effects, and a Chronic subscale, measuring the severity of long-term behavioural and cognitive side-effects. These subscales for side-effects showed a high correlation and can be used as a joint scale. These scales have the potential to improve outcome assessment in childhood epilepsy and they can be used to assess important aspects of quality of life in this population.

Adolescent↗
PubMed2005

Improving subjective scaling of pain using Rasch analysis.

UNLABELLED: Pain management outcomes assessment depends on valid measurement of pain. However, the validity of single-item scales, such as numeric or faces scales, with the assignment of ordinal numerical values to response scale categories, is questionable. The universal assumption that equal distances between response choices represent equal distances on the dimension being measured is essentially erroneous. Herein we demonstrate that Rasch analysis can be used to expose and repair scale inequity and reengineer scale structure. Thirty-one subjects with severe ocular surface disease repeatedly completed a 7-category faces pain scale. Rasch analysis demonstrated that response category 5 was underutilized, leading to disordering of the response scale. Collapsing category 5 into either category 4 or 6 produced an ordered 6-category faces scale that could be recalibrated with average Rasch person measures to create linear measurement on a continuous latent variable. The value of further alterations to the scale was explored, and the implication for scale redesign discussed. Rasch analysis could be applied to any subjective pain measure post-hoc to create linear measurement or applied during instrument development to optimize design. PERSPECTIVE: Single-item scales like the faces scale or a 1-10 numerical rating scale are commonly used for the subjective assessment of pain. However, scores applied to response categories are arbitrary, so do not represent equidistant steps in the underlying latent variable (pain). Scale inequities are easily demonstrable and repairable with Rasch analysis.

Adult↗
PubMed2003

Development and testing of a Faces Scale for the assessment of anxiety in critically ill patients.

BACKGROUND: Many patients experience anxiety during treatment in an intensive care unit, but intensive care patients are often not able to respond to existing validated measures of anxiety such as the Brief Symptom Inventory. We have developed a new single item Faces Anxiety Scale made up of drawings of five faces. AIMS: The aims of this study were to: (i) assess the ability of intensive care patients to respond to the Faces Anxiety Scale; and (ii) investigate whether the scale yields ordinal and interval data. ETHICS: The project was approved by two Human Research Ethics Committees. Patients were included in the study if they gave informed consent. INSTRUMENTS AND METHODS: (i) Intensive care patients (n = 40) were asked to respond to the Faces Anxiety Scale, the anxiety subscale of the Brief Symptom Inventory, and a numerical analogue anxiety scale; and (ii) Hospital and University staff and students (n = 75) were asked to place the five faces in rank order. A further 100 staff members and students were asked to place each face at a point on a 60-cm triangular wedge according to the level of anxiety they thought the face showed. RESULTS: The Faces Anxiety Scale elicited more responses from intensive care patients than the numerical analogue anxiety scale the or anxiety subscale of the Brief Symptom Inventory (36 vs. 25 vs. 17, respectively, P < 0.0001). In the testing of the order of the scale items, 93% of respondents independently placed the scale items in the order of least to most anxiety as intended in the design of the scale. In the testing for equality of intervals respondents placed the faces relatively equidistant, with no overlap of 95% confidence intervals around the mean distances. CONCLUSION: The Faces Anxiety Scale has minimal subject burden, elicits self report from intensive care patients more often than other simple scales, and has evidence of the interval scale properties of rank order and equality between the points on the scale.

Adult↗
PubMed1997

Color pattern formation on the wing of a butterfly Pieris rapae. 2. Color determination and scale development.

It has been shown that microcautery on the prospective apical black region of the early pupal forewing of a butterfly, Pieris rapae, causes alteration of the scale color on the adult wing and a delay in histogenesis of the pupal wing. From these results, it has been assumed that the developmental delay of scale cells in the pupal wing alters their developmental fate and the hypothesis that different color fates of scales are determined by differences in the developmental timetables between scale cells is proposed. In this study, we attempted to find the developmental timetables of individual scales expressing specific color to test this hypothesis. It was found that the holes on the upper surface of a scale become larger as they develop and the hole sizes of scales in the white region are always larger than in the black region on the same wings either during pupal period or after eclosion. This suggests that the scale hole size is a good index that reflects developmental rate of the scale and a difference in the hole size between adult scales is attributed to a difference in the developmental timetables when their ancestral scale precursor cells were in the pupal period. A comparison of the hole sizes between adult scales in different color regions suggested that normal white scales were in a more advanced state than were the black ones but white scales induced by microcautery were in a less advanced state than black ones on the same wing. This supports our hypothesis.

Animals↗
PubMedDate not supplied

Equal appearing interval and visual analogue scaling of perceptual roughness and breathiness.

One of the factors that affects the reliability of perceptual voice evaluation is the rating scale. Equal-appearing interval (EAI) and visual analogue (VA) scales are the two most common scales used and have attracted much attention in recent studies of perceptual voice evaluation. Available findings are contradictory, with one study finding the EAI scale to be more desirable while an earlier study showed equivocal results. The objective of the present study was to compare the reliability of using an 11-point EAI scale and a VA scale, each of 10cm long, for perceptual voice quality evaluation. Thirty listeners with no prior experience in perceptual voice evaluation were asked to rate the breathy and rough qualities of 28 voice samples. The results showed that the listeners demonstrated a significantly higher intra-rater agreement and lower inter-rater variability in rating the two perceptual voice qualities using the EAI scale, when compared to the VA scale. However, listeners tend to show more bias in using certain points on the EAI scale than on the VA scale. In addition, a linear relationship was found between the EAI and VA ratings, suggesting the psychoperceptual characteristics of breathy and rough qualities could be captured equally well by the EAI and VA scales. Since the ease of use of the rating scale is an important consideration in clinical situations, the 11-point, 10cm long EAI scale is therefore more preferable, although not necessarily more superior, than the VA scale for evaluating breathy and rough qualities.

Adult↗
PubMed2005

Costs of scaling up health interventions: a systematic review.

National governments and international agencies, including programmes like the Global Alliance for Vaccines and Immunizations and the Global Fund to Fight AIDS, Tuberculosis and Malaria, have committed to scaling up health interventions and to meeting the Millennium Development Goals (MDGs), and need information on costs of scaling up these interventions. However, there has been no systematic attempt across health interventions to determine the impact of scaling up on the costs of programmes. This paper presents a systematic review of the literature on the costs of scaling up health interventions. The objectives of this review are to identify factors affecting costs as coverage increases and to describe typical cost curves for different kinds of interventions. Thirty-seven studies were found, three containing cost data from programmes that had already been scaled up. The other studies provide either quantitative cost projections or qualitative descriptions of factors affecting costs when interventions are scaled up, and are used to determine important factors to consider when scaling up. Cost curves for the scaling up of different health interventions could not be derived with the available data. This review demonstrates that the costs of scaling up an intervention are specific to both the type of intervention and its particular setting. However, the literature indicates general principles that can guide the process: (1) calculate separate unit costs for urban and rural populations; (2) identify economies and diseconomies of scale, and separate the fixed and variable components of the costs; (3) assess availability and capacity of health human resources; and (4) include administrative costs, which can constitute a significant proportion of scale-up costs in the short run. This study is limited by the scarcity of real data reported in the public domain that address costs when scaling up health interventions. As coverage of health interventions increases in the process of meeting the MDGs and other health goals, it is recommended that costs of scaling up are reported alongside the impact on health of the scaled-up interventions.

Geography↗
PubMed2004

A pictorial sleepiness scale based on cartoon faces.

STUDY OBJECTIVES: To develop a sleepiness scale devoid of semantic or geometric elements. DESIGN: Subjects were asked to rank in order 7 cartoon faces representing degrees of sleepiness. We used Thurstone's scaling procedure to transform these rankings into an interval scale, which allowed us to eliminate 2 of the faces. The remaining 5 faces were ranked again using other subjects. In a validation study, subjects rated their perceived level of sleepiness using our scale and other sleepiness scales. Employed shiftworkers and school-going children used our scale to assess its practical applicability. SETTINGS: Research and diagnostic sleep laboratories, pre-primary to tertiary institutions, shift-working industry. PARTICIPANTS: Ethnically diverse healthy and sleep-disordered adults (n = 490), and school-going children (n = 345). MEASUREMENTS AND RESULTS: Our faces scale correlated with the Karolinska Sleepiness Scale (P < .05), the Stanford Sleepiness Scale (P < .04), and a visual analog scale measuring sleepiness (P < .0001). Shiftworkers showed a time-on-task effect on the evening shift (P < .0001) and a peak in sleepiness at 4:00 and 5:00 (P < .0001) on the night shift. Eight to 10 year old children appeared sleepier than older children throughout a school day (P < or = .02) and became sleepier as the day progressed (P < .0001). We confirmed that our scale measures sleepiness, uncontaminated by pain, anger, or happiness. CONCLUSIONS: We have devised a sleepiness scale suitable for people too young or insufficiently educated to employ more-conventional scales. We envisage the scale being used for diagnostic, therapeutic, and research purposes.

Adolescent↗
PubMedDate not supplied

Sensitivity of pain rating scales in an endoscopy trial.

OBJECTIVE: The purpose of this study was to compare the sensitivity of two commonly used pain-rating scales, the Visual Analog Scale and the 4-point verbal rating scale. Both are considered reliable and valid, but previous studies regarding sensitivity of rating scales have lead to different conclusions, and there is no firm agreement as to the best scale to choose. METHODS: The sensitivity of the Visual Analog Scale and the 4-point verbal rating scale was compared by stochastic simulation. In the simulation model, we used 168 pairs of pain ratings on the Visual Analog Scale and the 4-point verbal rating scale from individuals undergoing a lower gastrointestinal endoscopy, maintaining the true relation between ratings from the same individual. We created empirical distributions mimicking 2 independent groups of pain ratings. Random samples from the 2 groups were compared by the Wilcoxon-Mann-Whitney U test in 10,000 repetitions of a computer algorithm. By increasing the proportion of individuals with a high level of pain in one group, we increased the true difference between pain ratings and estimated a statistical power function. RESULTS: In the present pain model with pain ratings from healthy individuals undergoing endoscopy, the Visual Analog Scale is consistently more sensitive than the four-point verbal rating scale. DISCUSSION: Because each individual provided one Visual Analog Scale and one 4-point verbal rating scale rating for the same pain experience, the ability of the two scales to detect differences between groups of pain ratings could be compared. The use of a simulation model enabled estimation of a power function and reduced the probability of basing the conclusion on a chance finding.

Colonoscopy↗
PubMed2004

A low back-specific version of the SF-36 Physical Functioning scale.

STUDY DESIGN: A prospective repeated measures design was used to produce a back-specific version of the Short Form-36 Physical Functioning scale (SF-36 PF) by Rasch analysis of a pool of items from the SF-36 PF, Oswestry Disability Questionnaire, and the Quebec Back Pain Disability Scale. OBJECTIVES: To identify items for a back-specific version of the SF-36 PF scale and to compare the psychometric properties of the new version with the original 10-item scale. SUMMARY OF BACKGROUND DATA: Adequate assessment of patient function requires the administration of a generic and a condition-specific questionnaire. A back-specific version of the SF-36 PF would facilitate comprehensive patient assessment in the clinical setting. METHODS: Consecutive patients with low back pain presenting for physiotherapy treatment were recruited at three public hospitals, three community health services, and four private practices. Patients completed questionnaires on two occasions 6 weeks apart. RESULTS: A scale of 18 items showed a better fit to the Rasch model than the original SF-36 PF scale. Items in the original scale that had a poor fit (INFIT/OUTFIT statistics outside the range 0.7-1.3) showed an acceptable fit in the new scale. The augmented scale had comparable reliability and improved responsiveness to the original 10-item SF-36 PF scale. The minimum detectable change (90% confidence) and the minimum clinically important difference were 12 points. Floor and ceiling effects were practically eliminated. The psychometric properties of the new scale were comparable to those of the Oswestry Disability Questionnaire. CONCLUSIONS: The Low-Back SF-36 PF18 comprises the 10-item SF-36 PF scale and four items each from the Oswestry and Quebec back pain questionnaires. The possible total score ranges from 0 to 100, with a higher score indicating better function. The new scale appears to offer advantages over the use of the original scale for the assessment of functioning in patients with low back pain.

Adolescent↗
PubMed1994

Validation of four scales for the acute stage of stroke.

OBJECTIVES: To validate whether a simplified scale for the acute stage of stroke--the Scandinavian Stroke Supervision scale--is sufficient for monitoring symptom progression of prognostic importance. DESIGN: The capacity of the scale was compared to that of the Mathew, Toronto and Fugl-Meyer stroke scales and the Barthel ADL index. SETTING: The stroke unit of Danderyd Hospital, which cares for a defined population. SUBJECTS: Fifty noncomatose patients with objectively recorded symptoms at entry were examined over a period of 5 days by one physician (250 ratings/scale). The last 10 patients were also investigated by another doctor in the same manner (50 ratings/scale) and by nurses (50 ratings) the Scandinavian scale only. The amount of time required by each scale was tested in another 10 patients by two nurses (100 ratings/scale). INTERVENTIONS: Routine investigation and treatment. MAIN OUTCOME MEASURES: The reliability, validity, time requirement and correlation of the scales were evaluated, as was their ability to reveal progress of symptoms. RESULTS: All scales were highly significantly correlated. The interobserver agreement was excellent between the physicians but not as good between the physician and the nurses. The prediction of the outcome at discharge and after 3 months was very satisfactory for all of the scales with regard to the whole groups of patients, but none of them could predict the outcome for an individual with certainty. The Scandinavian Stroke Supervision scale was least time consuming, and had the fewest uncertainties expressed by the testers. This scale recorded the progression of slightly fewer symptoms, but did record those with a more serious impact on patient outcome. CONCLUSION: The time-saving, simplified Scandinavian scale was as reliable and as valid as the other scales, and detected deterioration that was important for patient outcome as satisfactorily as the other scales.

Acute Disease↗
PubMedDate not supplied

Coupling basin- and site-scale inverse models of the Española aquifer.

Large-scale models are frequently used to estimate fluxes to small-scale models. The uncertainty associated with these flux estimates, however, is rarely addressed. We present a case study from the Española Basin, northern New Mexico, where we use a basin-scale model coupled with a high-resolution, nested site-scale model. Both models are three-dimensional and are analyzed by codes FEHM and PEST. Using constrained nonlinear optimization, we examine the effect of parameter uncertainty in the basin-scale model on the nonlinear confidence limits of predicted fluxes to the site-scale model. We find that some of the fluxes are very well constrained, while for others there is fairly large uncertainty. Site-scale transport simulation results, however, are relatively insensitive to the estimated uncertainty in the fluxes. We also compare parameter estimates obtained by the basin- and site-scale inverse models. Differences in the model grid resolution (scale of parameter estimation) result in differing delineation of hydrostratigraphic units, so the two models produce different estimates for some units. The effect is similar to the observed scale effect in medium properties owing to differences in tested volume. More important, estimation uncertainty of model parameters is quite different at the two scales. Overall, the basin inverse model resulted in significantly lower estimates of uncertainty, because of the larger calibration dataset available. This suggests that the basin-scale model contributes not only important boundary condition information but also improved parameter identification for some units. Our results demonstrate that caution is warranted when applying parameter estimates inferred from a large-scale model to small-scale simulations, and vice versa.

Calibration↗
PubMedDate not supplied

Correlation of instrumental voice evaluation with perceptual voice analysis using a modified visual analog scale.

Various rating scales have been used for perceptual voice analysis including ordinal (ORD) scales and visual analog (VA) scales. The purpose of this study was to determine the most suitable scale for studies using perceptual voice analysis as a gold standard for validation of objective analysis protocols. The study was carried out on 74 female voice samples from 68 dysphonic patients and 6 controls. A panel of 4 raters with experience in perceptual analysis was asked to score voices according to the G component (overall quality) of the GRBAS system. Two rating scales were used. The first was a conventional 4-point ORD scale. The second was a modified VA (mVA) scale obtained by transforming the VA scale into an ORD scale using a weighted conversion scheme. Objective voice evaluation was performed using the EVA workstation. Objective measurements included acoustic, aerodynamic, and physiologic parameters as well as parameters based on nonlinear mathematics (e.g., Lyapunov coefficient). Instrumental measurements were compared with results of perceptual analysis using either the conventional ORD scale or mVA scale. Results demonstrate that correlation between perceptual and objective voice judgments is better using a mVA scale than a conventional ORD scale (concordance, 88 vs. 64%). Data also indicate that the mVA scale described herein improves the correlation between objective and perceptual voice analysis.

Adult↗
PubMedDate not supplied

An experimental test of a theoretical foundation for rating-scale valuations.

A major advantage of using a rating scale in health-utility measurement is its practical applicability: the method is relatively easy to understand, and various health states can be assessed simultaneously. However, a theoretical foundation for rating-scale valuations has not been established. The primary aim of this paper is to present a theoretical foundation for rating-scale valuations based on the theory of measurable value functions and to provide a consistency test to see whether rating-scale valuations do indeed elicit a measurable value function. If rating-scale valuations elicit a measurable value function, then Dyer and Sarin have shown how they are related to von Neumann-Morgensterm (vNM) utilities. The appropriate technique to measure vNM utilities is the standard gamble. Torrance has suggested that rating-scale valuations and standard-gamble valuations are related by a power function. A secondary aim of this paper is to examine the relationship between rating-scale valuations and standard-gamble valuations hypothesized by Torrance. An experiment was designed to test consistency of rating-scale valuations and the relationship between rating-scale valuations and standard-gamble valuations. The experiment tested whether rating-scale valuations are independent of the context in which they are elicited, as they should be if they elicit points on a measurable value function. 80 Swedish and 92 Dutch respondents participated in the experiment. The results showed that rating-scale valuations depend on the number of preferred alternatives in the task and thus violate a basic property of measurable value functions. The estimation of the power function did not result in stable results: parameter estimates varied, in some cases there was indication of misspecification, and in most cases there was indication of heteroskedastic errors. The implications of these findings for the common use of rating-scale valuations in cost-utility analysis are serious: the dependency of the rating-scale valuations on the other health states included in the task casts serious doubts on the validity of the rating-scale method.

Activities of Daily Living↗