Daphna Harel

Measuring fatigue in SSc: a comparison of the Short Form-36 Vitality subscale and Functional Assessment of Chronic Illness Therapy–Fatigue scale

OBJECTIVE Fatigue is a common and important problem in SSc. No studies, however, have compared the properties of fatigue measures in SSc. The objective of this study was to compare the performances of the Short Form-36 (SF-36) Vitality subscale and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT) in SSc. METHODS Cross-sectional, multi-centre study of Canadian Scleroderma Research Group Registry patients. The associations of the two instruments with other patient-reported outcome measures, as well as physician- and patient-rated disease variables were compared. Item response theory models were used to compare the degree to which items and the total scores of each measure effectively covered the full spectrum of fatigue levels. RESULTS There were 348 patients (297 women, 85%) in the study. The instruments correlated at r = 0.65 with each other. The FACIT tended to correlate slightly higher than the SF-36 Vitality subscale with physician- and patient-rated disease variables and patient-reported physical function and disability, whereas the SF-36 Vitality subscale correlated minimally higher with mental health measures. The FACIT had markedly better discrimination across the range of fatigue, particularly at average to high fatigue levels, whereas the SF-36 Vitality subscale discriminated well only among patients in the low to average range. CONCLUSION The FACIT discriminates better than the SF-36 Vitality subscale at average to high ranges of fatigue, which is common in SSc, suggesting that it is preferred for measuring fatigue in SSc.

Social, Emotional, and Academic Impact of Residual Speech Errors in School-Aged Children: A Survey Study

Children with residual speech errors face an increased risk of social, emotional, and/or academic challenges relative to their peers with typical speech. Previous research has shown that the effects of speech sound disorder may persist into adulthood and span multiple domains of activity limitations and/or participation restrictions, as defined by the World Health Organizations International Classification of Functioning, Disability and Health model. However, the nature and extent of these influences varies widely across children. This study aimed to expand the evidence base on the social, emotional, and academic impact of residual speech errors by collecting survey data from parents of children receiving treatment for /r/ misarticulation. By examining the relationship between an overall measure of impact (weighted summed score) and responses to 11 survey items, the present study offers preliminary suggestions for factors that could be considered when making decisions pertaining to treatment allocation in this population.

Using Optimal Test Assembly Methods for Shortening Patient-Reported Outcome Measures: Development and Validation of the Cochin Hand Function Scale-6: A Scleroderma Patient-Centered Intervention Network Cohort Study.

To develop and validate a short form of the Cochin Hand Function Scale (CHFS), which measures hand disability, for use in systemic sclerosis, using objective criteria and reproducible techniques.

Finding the experts in the crowd: Validity and reliability of crowdsourced measures of children’s gradient speech contrasts

ABSTRACT Perceptual ratings aggregated across multiple nonexpert listeners can be used to measure covert contrast in child speech. Online crowdsourcing provides access to a large pool of raters, but for practical purposes, researchers may wish to use smaller samples. The ratings obtained from these smaller samples may not maintain the high levels of validity seen in larger samples. This study aims to measure the validity and reliability of crowdsourced continuous ratings of child speech, obtained through Visual Analog Scaling, and to identify ways to improve these measurements. We first assess overall validity and interrater reliability for measurements obtained from a large set of raters. Second, we investigate two rater-level measures of quality, individual validity and intrarater reliability, and examine the relationship between them. Third, we show that these estimates may be used to establish guidelines for the inclusion of raters, thus impacting the quality of results obtained when smaller samples are used.

Summed and Weighted Summary Scores for the Medsger Disease Severity Scale Compared with the Physician’s Global Assessment of Disease Severity in Systemic Sclerosis

Objective. To develop a weighted summary score for the Medsger Disease Severity Scale (DSS) and to compare its measurement properties with those of a summed DSS score and a physician’s global assessment (PGA) of severity score in systemic sclerosis (SSc). Methods. Data from 875 patients with SSc enrolled in a multisite observational research cohort were extracted from a central database. Item response theory was used to estimate weights for the DSS weighted score. Intraclass correlation coefficients (ICC) and convergent, discriminative, and predictive validity of the 3 summary measures in relation to patient-reported outcomes (PRO) and mortality were compared. Results. Mean PGA was 2.69 (SD 2.16, range 0–10), mean DSS summed score was 8.60 (SD 4.02, range 0–36), and mean DSS weighted score was 8.11 (SD 4.05, range 0–36). ICC were similar for all 3 measures [PGA 6.9%, 95% credible intervals (CrI) 2.1–16.2; DSS summed score 2.5%, 95% CrI 0.4–6.7; DSS weighted score 2.0%, 95% CrI 0.1–5.6]. Convergent and discriminative validity of the 3 measures for PRO were largely similar. In Cox proportional hazards models adjusting for age and sex, the 3 measures had similar predictive ability for mortality (adjusted R2 13.9% for PGA, 12.3% for DSS summed score, and 10.7% DSS weighted score). Conclusion. The 3 summary scores appear valid and perform similarly. However, there were some concerns with the weights computed for individual DSS scales, with unexpected low weights attributed to lung, heart, and kidney, leading the PGA to be the preferred measure at this time. Further work refining the DSS could improve the measurement properties of the DSS summary scores.

On the effects of signal processing on sample entropy for postural control

Sample entropy, a measure of time series regularity, has become increasingly popular in postural control research. We are developing a virtual reality assessment of sensory integration for postural control in people with vestibular dysfunction and wished to apply sample entropy as an outcome measure. However, despite the common use of sample entropy to quantify postural sway, we found lack of consistency in the literature regarding center-of-pressure signal manipulations prior to the computation of sample entropy. We therefore wished to investigate the effect of parameters choice and signal processing on participants’ sample entropy outcome. For that purpose, we compared center-of-pressure sample entropy data between patients with vestibular dysfunction and age-matched controls. Within our assessment, participants observed virtual reality scenes, while standing on floor or a compliant surface. We then analyzed the effect of: modification of the radius of similarity (r) and the embedding dimension (m); down-sampling or filtering and differencing or detrending. When analyzing the raw center-of-pressure data, we found a significant main effect of surface in medio-lateral and anterior-posterior directions across r’s and m’s. We also found a significant interaction group × surface in the medio-lateral direction when r was 0.05 or 0.1 with a monotonic increase in p value with increasing r in both m’s. These effects were maintained with down-sampling by 2, 3, and 4 and with detrending but not with filtering and differencing. Based on these findings, we suggest that for sample entropy to be compared across postural control studies, there needs to be increased consistency, particularly of signal handling prior to the calculation of sample entropy. Procedures such as filtering, differencing or detrending affect sample entropy values and could artificially alter the time series pattern. Therefore, if such procedures are performed they should be well justified.

Methods for shortening patient-reported outcome measures

Patient-reported outcome measures are widely used to assess patient experiences, well-being, and treatment response in clinical trials and cohort-based observational studies. However, patients may be asked to respond to many different measures in order to provide researchers and clinicians with a wide array of information regarding their experiences. Collecting such long and cumbersome patient-reported outcome measures may burden patients, increase research costs, and potentially reduce the quality of the data collected. Nonetheless, little research has been conducted on replicable, and reproducible methods to shorten these instruments that result in shortened forms of minimal length. This manuscript proposes the use of mixed integer programming through Optimal Test Assembly as a method to shorten patient-reported outcome measures. This method is compared to the existing standard in the field, which is selecting items based on having high discrimination parameters from an item response theory model. The method is then illustrated in an application to a fatigue scale for patients with Systemic Sclerosis.

Selecting an acoustic correlate for automated measurement of American English rhotic production in children

Abstract Purpose: A current need in the field of speech–language pathology is the development of reliable and efficient techniques to evaluate accuracy of speech targets over the course of treatment. As acoustic measurement techniques improve, it should become possible to use automated scoring in lieu of ratings from a trained clinician in some contexts. This study asks which acoustic measures correspond most closely with expert ratings of children’s productions of American English /ɹ/ in an effort to develop an automated scoring algorithm for use in treatment targeting rhotics. Method: A series of ordinal mixed-effects regression models were fit over a large sample of childrens productions of words containing /ɹ/ that had previously been rated by three trained clinicians. Akaike/Bayesian Information Criteria were used to select the best-fitting model. Result: Controlling for age, sex, and allophonic contextual differences, the measure that accounted for the most variance in speech rating was F3–F2 distance normalised relative to a sample of age- and sex-matched speakers. Conclusion: We recommend this acoustic measure for use in future automated scoring of children’s production of American English rhotics. We also suggest that computer-based treatment with automated scoring should facilitate increases in treatment dosage by improving options for home practice.

Feasibility and reliability of a virtual reality oculus platform to measure sensory integration for postural control in young adults

ABSTRACT Background: Using Unity for the Oculus Development-Kit 2, we have developed an affordable, portable virtual reality platform that targets the visuomotor domain, a missing link in current clinical assessments of postural control. Here, we describe the design and technical development as well as report its feasibility with regards to cybersickness and test-retest reliability in healthy young adults. Method: Our virtual reality paradigm includes two functional scenes (‘City’ and ‘Park’) and four moving dots scenes. Twenty-one healthy young adults were tested twice, one to two weeks apart. They completed a simulator sickness questionnaire several times per session. Their postural sway response was recorded from a forceplate underneath their feet while standing on the floor, stability trainers, or a Both Sides Up (BOSU) ball. Sample entropy, postural displacement, velocity, and excursion were calculated and compared between sessions given the visual and surface conditions. Results: Participants reported slight-to-moderate transient side effects. Intra-Class Correlation values mostly ranged from 0.5 to 0.7 for displacement and velocity, were above 0.5 (stability trainer conditions) and above 0.4 (floor mediolateral conditions) for sample entropy, and minimal for excursion. Conclusion: Our novel portable VR platform was found to be feasible and reliable in healthy young adults.

An Information Matrix Test for the Collapsing of Categories Under the Partial Credit Model

Collapsing categories is a commonly used data reduction technique; however, to date there do not exist principled methods to determine whether collapsing categories is appropriate in practice. With ordinal responses under the partial credit model, when collapsing categories, the true model for the collapsed data is no longer a partial credit model, and therefore refitting a partial credit model may result in model misspecification. This article details the implementation and performance of an information matrix test (IMT) to assess the implications of collapsing categories for a given data set under the partial credit model and compares its performance to the application of a nominal response model (NRM) and the S − X2 goodness-of-fit statistic. The IMT and NRM-based test are able to correctly determine the true number of categories for an item, given reasonable power through this goodness-of-fit test. We conclude by applying the test to a well-studied data set from the literature.