Interpreting results from Rasch analysis 1. The "most likely" measures coming from the model

Outpatients' perspectives of quality in rehabilitation - development and validation of a patient-reported experience measure (PREM)

PURPOSE

This study aimed to develop and validate a patient-reported experience measure (PREM) to examine the patients' perspectives on the quality of outpatient physiotherapy and occupational therapy rehabilitation.

MATERIALS AND METHODS

A systematic literature search in PubMed, Embase, Scopus, and Cinahl was conducted to identify relevant themes for the questionnaire. Fourteen studies were analyzed through a systematic text condensation to identify quality aspects in the rehabilitation from patients' perspectives. Further, based on the analysis, 13 items with answers on a five-point Likert scale were developed. Face validity and content validity were established during interviewing 14 municipality outpatients. Finally, to determine the construct validity and internal consistency, the questionnaire was distributed to 385 patients with various diagnoses.

RESULTS

The final questionnaire, Outpatients' Experience of quality in Rehabilitation (OPER), demonstrated good face and content validity and covered patients' experience of quality in municipal rehabilitation. Data from 307 respondents established construct validity and high internal consistency and showed, in general, a positive experience of outpatient rehabilitation.

CONCLUSIONS

The OPER demonstrates satisfactory psychometric properties based on an extensive development and validation process. By assessing outpatients' experience of the rehabilitation process, OPER offers a measurement of the quality of therapists' practice of patient-centered rehabilitation.

A Multi-Sample Comparison and Rasch Analysis of the Evaluation of Children's Listening and Processing Skills Questionnaire

OBJECTIVES

Assessing listening difficulties and associated complaints can be challenging. Often, measures of peripheral auditory functions are within normal ranges, making clinicians feel unsure about proper management strategies. The range and nature of observed or experienced difficulties might be better captured using a qualitative measure. The Evaluation of Children's Listening and Processing Skills (ECLiPS) questionnaire was designed to broadly profile the auditory and cognitive problems often present in children with listening difficulties. This 38-item questionnaire was initially standardized in British children aged 6 to 11 years, was subsequently modified for use with North-American children, and was recently translated into Flemish-Dutch. This study aimed to compare typical scores of the Flemish version with the UK and US versions, and to evaluate and compare its psychometric quality based on Rasch analysis.

DESIGN

We selected 112 Flemish children aged 6 to 11 years with verified normal hearing and typical development, and asked two caregivers of every child to fill out the ECLiPS. Data from two comparator samples were analyzed, including responses for 71 North-American children and 650 British children. Typical values for ECLiPS factors and aggregates were determined as a function of age and gender, and meaningful differences across samples were analyzed. Rasch analyses were performed to evaluate whether ECLiPS response categories work as intended, and whether item scores fit a linear equal interval measurement scale that works the same way for everyone. Item and person metrics were derived, including separation and reliability indices. We investigated whether items function similarly across linguistically and culturally different samples.

RESULTS

ECLiPS scores were relatively invariant to age. Girls obtained higher scores compared with boys, mainly for items related to memory and attention, and pragmatic and social skills. Across ECLiPS versions, the most pronounced differences were found for items probing social skills. With respect to its psychometric quality, ECLiPS response categories work as intended, and ECLiPS items were found to fit the Rasch measurement scale. Cultural differences in responses were noted for some items, belonging to different factors. Item separation and reliability indices generally pointed toward sufficient variation in item difficulty. In general, person separation (and reliability) metrics, quantifying the instrument's ability to distinguish between poor and strong performers (in a reproducible manner), were low. This is expected from samples of typically developing children with homogeneous and high levels of listening ability.

CONCLUSIONS

Across the languages assessed here, the ECLiPS caregiver questionnaire was verified to be a psychometrically valid qualitative measure to assess listening and processing skills, which can be used to support the assessment and management of elementary school children referred with LiD.

In Myotonic Dystrophy Type 1 Head Repositioning Errors Suggest Impaired Cervical Proprioception

Background: Myotonic dystrophy type 1 (DM1) is a rare multisystemic genetic disorder with motor hallmarks of myotonia, muscle weakness and wasting. DM1 patients have an increased risk of falling of multifactorial origin, and proprioceptive and vestibular deficits can contribute to this risk. Abnormalities of muscle spindles in DM1 have been known for years. This observational cross-sectional study was based on the hypothesis of impaired cervical proprioception caused by alterations in the neck spindles. Methods: Head position sense was measured in 16 DM1 patients and 16 age- and gender-matched controls. A head-to-target repositioning test was requested from blindfolded participants. Their head was passively rotated approximately 30° leftward or rightward and flexed or extended approximately 25°. Participants had to replicate the imposed positions. An optoelectronic system was adopted to measure the angular differences between the reproduced and the imposed positions (joint position error, JPE, °) concerning the intended (sagittal, horizontal) and unintended (including the frontal) planar projections. In DM1 patients, JPEs were correlated with clinical and balance measures. Static balance in DM1 patients was assessed through dynamic posturography. Results: The accuracy and precision of head repositioning in the intended sagittal and horizontal error components did not differ between DM1 and controls. On the contrary, DM1 patients showed unintended side-bending to the left and the right: the mean [95%CI] of frontal JPE was -1.29° [-1.99°, -0.60°] for left rotation and 0.98° [0.28°, 1.67°] for right rotation. The frontal JPE of controls did not differ significantly from 0° (left rotation: 0.17° [-0.53°, 0.87°]; right rotation: -0.22° [-0.91°, 0.48°]). Frontal JPE differed between left and right rotation trials (p < 0.001) only in DM1 patients. No correlation was found between JPEs and measures from dynamic posturography and clinical scales. Conclusions: Lateral head bending associated with head rotation may reflect a latent impairment of neck proprioception in DM1 patients.

Development and validation of the Dermatology Social Comparison (DSC) Scale

BACKGROUND

Social comparison, the process of evaluating one's characteristics in relation to others, influences individuals' self-perception and behavior. However, instruments are scarce for assessing social comparison in the medical setting.

OBJECTIVES

Our aim was to develop and validate a new scale for assessing social comparison.

MATERIALS AND METHODS

Seven statements were developed, encompassing the perceived normality of having rashes, the tendency to compare their situation with others, and the emotional response when seeing someone better or worse off than themselves. The instrument was piloted in 15 patients for readability and face validity, then prospectively validated using modern psychometric methods in 1,053 adult patients with eczema or psoriasis from three tertiary dermatological centers in Singapore.

RESULTS

Of 1,053 adult patients, 802 (76.2%) had eczema, and 251 (23.8%) had psoriasis. Exploratory factor analysis (using a 70% sample split) showed a single factor model comprising three questions (Eigenvalue: 1.4). Confirmatory factor analysis with the remaining 30% of the sample confirmed an excellent model fit. Cronbach's alpha was 0.7, and inter-item correlations ranged from 0.42 to 0.46. In the Rasch analysis, item fit statistics and item characteristic curves showed appropriate discrimination between response options, although reliability was suboptimal with a person separation reliability of 0.63.

CONCLUSIONS

Comprising 3 questions, the newly derived social comparison scale showed acceptable psychometrics as a measure of social comparison for clinical and research purposes in dermatology. Its brief nature likely results from its brevity and applicability to conditions beyond eczema and psoriasis, which warrants further investigation.

Physical and Rehabilitation Medicine: say relational or functional, not holistic

Modern medicine tends to privilege disciplines promising "objective" laws governing body parts (from molecules to organs). Studies on a person's illness and disability are (apparently) confined to "subjectivity." The Specialty of Physical and Rehabilitation Medicine is often regarded as a humanitarian approach, belonging at best to the family of "soft," "qualitative," or "quasi-experimental" sciences. This specialty often claims specificity by labelling itself as "functional" and "holistic." However, it is shown here that the former term is acceptable, yet redundant, and the second misleading. When human behaviors and perceptions are at stake, "function" indicates a person's relationship with the outer world (already tackled by the definitional term "physical" from the Greek "physis"). The word "holistic" emphasizes mind-body unity and person-environment interdependence but, in current usage, overshadows the complementary need for an analytic, experimental approach to any function. Medicine aims at fighting disease and disability in single persons. This endeavor requires knowing body parts and mechanisms and understanding how interventions on "parts" affect the "whole." This understanding rests on the experimental method. For instance, returning to a given societal role (participation) may require restoration of walking (activity), which may require reinforcement of weakened muscular groups (impairment). Working only on holistic bio-psycho-social "wholes" may miss the therapeutic mission of medicine.

Interpreting results from Rasch analysis 2. Advanced model applications and the data-model fit assessment

Purpose: The present paper presents developments and advanced practical applications of Rasch's theory and statistical analysis to construct questionnaires for measuring a person's traits. The flaws of questionnaires providing raw scores are well known. Scores only approximate objective, linear measures. The Rasch Analysis allows you to turn raw scores into measures with an error estimate, satisfying fundamental measurement axioms (e.g., unidimensionality, linearity, generalizability). A previous companion article illustrated the most frequent graphic and numeric representations of results obtained through Rasch Analysis. A more advanced description of the method is presented here.Conclusions: Measures obtained through Rasch Analysis may foster the advancement of the scientific assessment of behaviours, perceptions, skills, attitudes, and knowledge so frequently faced in Physical and Rehabilitation Medicine, not less than in social and educational sciences. Furthermore, suggestions are given on interpreting and managing the inevitable discrepancies between observed scores and ideal measures (data-model "misfit"). Finally, twelve practical take-home messages for appraising published results are provided.Implications for rehabilitationThe current work is the second of two papers addressed to rehabilitation clinicians looking for an in-depth introduction to the Rasch analysis.The first paper illustrates the most common results reported in published papers presenting the Rasch analysis of questionnaires.The present article illustrates more advanced applications of the Rasch analysis, also frequently found in publications.Twelve take-home messages are given for a critical appraisal of the results.

Fatigue may improve equally after balance and endurance training in multiple sclerosis: a randomised, crossover clinical trial

Introduction

Fatigue and poor balance are frequent and severe problems in multiple sclerosis (MS) that may interact. Endurance training is known to be effective on fatigue. This study aims to test if balance training is more effective against MS fatigue.

Methods

A randomised crossover trial was run, recruiting 31 MS people (21 women; median age: 46 years, range: 30-64; median EDSS: 4, range: 2.5-5). Participants received balance and endurance training alternately (15 one-to-one sessions, 5 days/week) and were assessed before (T0), after (T1), and 30 days after treatment ended (T2). The Modified Fatigue Impact Scale (MFIS) with scores linearised through Rasch analysis was the primary outcome (the lower the measure, the better the condition, i.e., the lower the fatigue symptoms). The Equiscale balance scale and posturography (EquiTest) were used to assess balance. Linear mixed-effects models with ANOVA were used for significance testing.

Results

Thirteen participants had no carryover effect and were included in the primary analysis. Fatigue significantly changed across the three time points (F2,58 = 16.0; p < 0.001), but no difference across treatments was found. Altogether, both treatments significantly improved the MFIS measure at T1 (95%CI: -1.24 logits; mean: -1.67 to -0.81 logits) and T2 (95%CI: -1.04; mean: -1.49 to -0.60) compared to T0 (95%CI: -0.51; mean: -0.95 to -0.08; p ≤ 0.001). Equiscale and posturography highlighted balance improvement after balance training but not after endurance training.

Conclusion

Balance and endurance training could similarly reduce fatigue in MS patients in the short term. However, only balance training also improved balance in MS.

Pay attention: you can fall! The Mini-BESTest scale and the turning duration of the TUG test provide valid balance measures in neurological patients: a prospective study with falls as the balance criterion

Background

Balance, i.e., the ability not to fall, is often poor in neurological patients and this impairment increases their risk of falling. The Mini-Balance Evaluation System Test (Mini-BESTest), a rating scale, the Timed Up and Go (TUG) test, and gait measures are commonly used to quantify balance. This study assesses the criterion validity of these measures as balance measures.

Methods

The probability of being a faller within nine months was used as the balance criterion. The Mini-BESTest, TUG (instrumented with inertial sensors), and walking test were administered before and after inpatient rehabilitation. Multiple and LASSO logistic regressions were used for the analysis. The diagnostic accuracy of the model was assessed with the area under the curve (AUC) of the receiver operating characteristic curve. Mobility measure validity was compared with the Akaike Information Criterion (AIC).

Results

Two hundred and fourteen neurological patients (stroke, peripheral neuropathy, or parkinsonism) were recruited. In total, 82 patients fell at least once in the nine-month follow-up. The Mini-BESTest (AUC = 0.69; 95%CI: 0.62-0.76), the duration of the TUG turning phase (AUC = 0.69; 0.62-0.76), and other TUG measures were significant faller predictors in regression models. However, only the turning duration (AIC = 274.0) and Mini-BESTest (AIC = 276.1) substantially improved the prediction of a baseline model, which only included fall risk factors from the medical history (AIC = 281.7). The LASSO procedure selected gender, disease chronicity, urinary incontinence, the Mini-BESTest, and turning duration as optimal faller predictors.

Conclusion

The TUG turning duration and the Mini-BESTest predict the chance of being a faller. Their criterion validity as balance measures in neurological patients is substantial.

Sensory Modulation Abilities in Healthy Preterm-Born Children: An Observational Study Using the Sensory Processing and Self-Regulation Checklist (SPSRC)

This study aimed to investigate prematurity as a risk factor for sensory processing disorders, using the Italian Version of Sensory Processing and Self-Regulation Checklist (SPSRC-IT), based on a sample of healthy Italian children born preterm in comparison with a sample of typical full-term children. Two groups of caregivers of Italian healthy preschooler children were recruited. The first group comprised 37 caregivers of full-term children (FT), while the second group consisted of 37 caregivers of preterm children (PT) (gestational age < 37 weeks). Significant differences between the groups in several subsections and factors of the SPSRC-IT were found, specifically in the Physiological Conditions section, in the Gustatory and Olfactory Sense section, in the Vestibular Sense section, and in the Proprioceptive Sense section, with lower scores in the PT group. Moreover, children born at a lower gestational age or with lower weights had a higher risk of dysfunctions in processing gustatory and olfactory, vestibular, and proprioceptive stimuli. In conclusion, the SPSRC-IT suggested a potential link between prematurity and challenges in the development of sensory processing and self-regulation skills, especially in children with a very low birth weight and very low gestational age.

Exploring a New Application of Construct Specification Equations (CSEs) and Entropy: A Pilot Study with Balance Measurements

Both construct specification equations (CSEs) and entropy can be used to provide a specific, causal, and rigorously mathematical conceptualization of item attributes in order to provide fit-for-purpose measurements of person abilities. This has been previously demonstrated for memory measurements. It can also be reasonably expected to be applicable to other kinds of measures of human abilities and task difficulty in health care, but further exploration is needed about how to incorporate qualitative explanatory variables in the CSE formulation. In this paper we report two case studies exploring the possibilities of advancing CSE and entropy to include human functional balance measurements. In case study I, physiotherapists have formulated a CSE for balance task difficulty by principal component regression of empirical balance task difficulty values from Berg's Balance Scale transformed using the Rasch model. In case study II, four balance tasks of increasing difficulty due to diminishing bases of support and vision were briefly investigated in relation to entropy as a measure of the amount of information and order as well as physical thermodynamics. The pilot study has explored both methodological and conceptual possibilities and concerns to be considered in further work. The results should not be considered as fully comprehensive or absolute, but rather open up for further discussion and investigations to advance measurements of person balance ability in clinical practice, research, and trials.

Reversed Mirror Therapy (REMIT) after Stroke-A Proof-of-Concept Study

In mirror training (MIT), stroke patients strive to move their hands while looking at the reflected image of the unaffected one. The recruitment of the mirror neurons and visual-proprioceptive conflict are expected to facilitate the paretic voluntary movement. Here, a reversed MIT (REMIT) is presented, which requires moving hands while looking at the reflected image of the paretic one, giving the illusion of being unable to move the unimpaired hand. This study compares MIT and REMIT on post-stroke upper-limb recovery to gain clues on the mechanism of action of mirror therapies. Eight chronic stroke patients underwent two weeks of MIT and REMIT (five sessions each) in a crossover design. Upper-limb Fugl-Meyer, Box and Block and handgrip strength tests were administered at baseline and treatments end. The strength of the mirror illusion was evaluated after each session. MIT induced a larger illusory effect. The Fugl-Meyer score improved to the same extent after both treatments. No changes occurred in the Box and Block and the handgrip tests. REMIT and MIT were equally effective on upper-limb dexterity, challenging the exclusive role of mirror neurons. Contrasting learned nonuse through an intersensory conflict might provide the rationale for both forms of mirror-based rehabilitation after stroke.

Differential Item Functioning of the Mini-BESTest Balance Measure: A Rasch Analysis Study

The Mini-Balance Evaluation Systems Test (Mini-BESTest), a 14-item scale, has high content validity for balance assessment. This study further examines the construct validity of the Mini-BESTest with an emphasis on its measurement invariance. The Mini-BESTest was administered to 292 neurological patients in two sessions (before and after rehabilitation) and evaluated with the Rasch analysis (Many-Facet Rating Scale Model: persons, items, sessions). Categories' order and fit to the model were assessed. Next, maps, dimensionality, and differential item functioning (DIF) were examined for construct validity evaluation. DIF was inspected for several clinically important variables, including session, diagnosis, and assistive devices. Mini-BESTest items had ordered categories and fitted the Rasch model. The item map did not flag severe construct underrepresentation. The dimensionality analysis showed that another variable extraneous to balance affected the score of a few items. However, this multidimensionality had only a modest impact on measures. Session did not cause DIF. DIF for assistive devices affected six items and caused a severe measurement artefact. The measurement artefact caused by DIF for diagnosis was negligible. The Mini-BESTest returns interval measures with robust construct validity and measurement invariance. However, caution should be used when comparing Mini-BESTest measures obtained with and without assistive devices.