Rasch Validation of the Mini-BESTest in People With Parkinson Disease.

BACKGROUND AND PURPOSE: The Mini-BESTest is a balance measure with robust psychometric properties widely used in people with Parkinson disease. The aim of this study was to examine-with advanced psychometric techniques-some key properties of the Mini-BESTest (including unidimensionality, functioning of rating categories, internal construct validity, reliability indexes) in a consecutive sample of individuals with Parkinson disease admitted for balance rehabilitation. METHODS: Confirmatory factor analysis and Rasch analysis (partial credit model) were performed on 193 individual raw scores of the Mini-BESTest items. RESULTS: Confirmatory factor analysis fit indices and principal component analysis of the residuals confirmed the scale's unidimensionality. At Rasch analysis, the 3-level rating scale demonstrated appropriate functioning. All items fitted the Rasch model. Item response dependence was negligible. No differential item functioning was found across gender and age groups. DISCUSSION AND CONCLUSIONS: We confirmed and extended the evidence (demonstrated in different populations) on the general psychometric soundness of the Mini-BESTest, even when tested with rigorous statistical methods. In addition, 2 forms were created: (i) to transform raw scores into linear estimates of dynamic balance; and (ii) to compare the individual's item responses with those expected by the Rasch model (thus providing an aid for tailored interventions) and manage missing responses. Further independent studies using advanced psychometric techniques are warranted, also in people with balance disturbances of different etiology. Our study further increases the confidence in using the Mini-BESTest to assess dynamic balance in people with Parkinson disease and provides some useful additional clinical aids for interpreting the results and calculating more precise change scores.See the Supplementary Video, available at: http://links.lww.com/JNPT/A384.

Facial Disability Index in Adults With Peripheral Facial Palsy: Rasch Analysis and Suggestions for Refinement.

OBJECTIVE: To investigate the psychometric properties of the validated Italian version of the Facial Disability Index (FDI), a patient-reported outcome measure widely used to assess individuals with peripheral facial palsy. DESIGN: Methodological research on cross-sectional data from a convenience sample. SETTING: Outpatient university rehabilitation clinic. PARTICIPANTS: A total of 168 (N=168) outpatients (66% female; mean age, 44±15 years) with peripheral facial palsy of diverse etiology (48% postsurgical, 31% Bell palsy, 8% posttraumatic, 3% congenital, 11% other medical conditions) and severity at the first visit. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The 2 FDI subscales, physical function (FDI-PHY) and social/well-being function (FDI-SWB), were separately analyzed using classical test theory methods and Rasch analysis. RESULTS: Cronbach α was 0.79 in FDI-PHY and 0.74 in FDI-SWB, while item-rest correlation ranged from 0.36-0.67 in FDI-PHY and from 0.43-0.68 in FDI-SWB. In the FDI-PHY, we deleted 2 underused response categories, rescoring the remaining ones. In the FDI-SWB, some response categories did not function as expected by the Rasch model: their collapse into a 4-level format solved this problem. In each subscale, all items fitted the Rasch model except item 4 (eye tearing/becoming dry) in FDI-PHY that showed an unexpectedly high response variability. The person separation reliability of both subscales indicated that they are useful only for group-level judgments. In both subscales, principal component analysis of the residuals showed unidimensionality and absence of locally dependent items. No significant differential item functioning concerning sex, age, or time from paralysis emerged. CONCLUSIONS: Our study demonstrated overall positive psychometric characteristics of FDI except for the functioning of the response categories. We propose a refined version with 4 response categories only and related conversion graphs that may improve the interpretability, feasibility, and metric performance of this tool.

Cross-cultural adaptation, reliability and validity of the Fremantle Knee Awareness Questionnaire in Italian subjects with painful knee osteoarthritis.

BACKGROUND AND AIM: Growing attention is being given to utilising physical function measures to better understand and manage knee osteoarthritis (OA). The Fremantle Knee Awareness Questionnaire (FreKAQ), a self-reported measure of body-perception specific to the knee, has never been validated in Italian patients. The aims of this study were to culturally adapt and validate the Italian version of the FreKAQ (FreKAQ-I), to allow for its use with Italian-speaking patients with painful knee OA. METHODS: The FreKAQ-I was developed by means of forward-backward translation, a final review by an expert committee and a test of the pre-final version to evaluate its comprehensibility. The psychometric testing included: internal structural validity by Rasch analysis; construct validity by assessing hypotheses of FreKAQ correlations with the knee injury and osteoarthritis outcome score (KOOS), a pain intensity numerical rating scale (PI-NRS), the pain catastrophising scale (PCS), and the Hospital anxiety and depression score (HADS) (Pearson's correlations); known-group validity by evaluating the ability of FreKAQ scores to discriminate between two groups of participants with different clinical profiles (Mann-Whitney U test); reliability by internal consistency (Cronbach's alpha) and test-retest reliability (intraclass correlation coefficient, ICC2.1); and measurement error by calculating the minimum detectable change (MDC). RESULTS: It took one month to develop a consensus-based version of the FreKAQ-I. The questionnaire was administered to 102 subjects with painful knee OA and was well accepted. Internal structural validity confirmed the substantial unidimensionality of the FreKAQ-I: variance explained was 53.3%, the unexplained variance in the first contrast showed an eigenvalue of 1.8, and no local dependence was detected. Construct validity was good as all of the hypotheses were met; correlations: KOOS (rho = 0.38-0.51), PI-NRS (rho = 0.35-0.37), PCS (rho = 0.47) and HADS (Anxiety rho = 0.36; Depression rho = 0.43). Regarding known-groups validity, FreKAQ scores were significantly different between groups of participants demonstrating high and low levels of pain intensity, pain catastrophising, anxiety, depression and the four KOOS subscales (p ≤ 0.004). Internal consistency was acceptable (α = 0.74) and test-retest reliability was excellent (ICC = 0.92, CI 0.87-0.94). The MDC95 was 5.22 scale points. CONCLUSION: The FreKAQ-I is unidimensional, reliable and valid in Italian patients with painful knee OA. Its use is recommended for clinical and research purposes.

Validation of the Activities-Specific Balance Confidence Scale With 5-Option Response Format in Slovene Lower-Limb Prosthetic Users.

OBJECTIVE: To examine the psychometric properties of the Activities-specific Balance Confidence (ABC) scale administered in the Slovene version with a simplified 5-option response format (ABC-5/SLO) using Rasch analysis. DESIGN: Methodological research on data gathered in a cross-sectional study. SETTING: Outpatient university rehabilitation clinic. PARTICIPANTS: A convenience sample of adults with unilateral lower-limb amputation (N=138; 75% men) longer than 6 months who regularly wear a prosthesis. INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: We evaluated functioning of rating scale categories, internal construct validity, reliability indices, and dimensionality using the ABC-5/SLO (0=no confidence to 4=complete confidence). RESULTS: The ABC-5/SLO rating scale fulfilled the category functioning criteria. All items fit the underlying scale construct (balance confidence) except item 8 ("walk outside the house to a car parked in the driveway"), which was overfitting. The person abilities-item difficulty matching (targeting) was good. The person separation reliability was .92, and the item separation reliability was .99. Analysis of the standardized Rasch residuals showed the scale's unidimensionality and absence of high item dependency (residual correlations, <.30). The correlation between the ABC-5/SLO and the Prosthetic Mobility Questionnaire (Rasch measures) was high (ρ=.84), as expected. Minor signs of item redundancy were found. CONCLUSIONS: The simplified ABC-5/SLO scale is a valid and reliable measure of balance confidence for individuals with lower-limb amputation. It is possible to transform the ordinal summed raw scores of the ABC-5/SLO into interval-level measurements using a nomogram.

The Italian version of the Quebec Back Pain Disability Scale: cross-cultural adaptation, reliability and validity in patients with chronic low back pain.

BACKGROUND AND AIM: Growing attention is being given to physical functioning measures to assess interventions for low back pain (LBP). The Quebec Back Pain Disability Questionnaire (QBPDS) has never been validated in Italian patients, and the aim of the study was culturally adapting and validating the Italian version of the QBPDS (QBPDS-I), to allow its use with Italian-speaking patients with chronic LBP. METHODS: The QBPDS-I was developed by means of forward-backward translation, a final review by an expert committee and a test of the prefinal version to evaluate its comprehensibility. The psychometric testing included structural validity by exploratory factor analysis (EFA), reliability by internal consistency (Cronbach's alpha) and test-retest reliability (intraclass correlation coefficient, ICC 2.1), measurement error by calculating the minimum detectable change (MDC), construct validity by assessing hypotheses of QBPDS correlations with the Roland Morris Disability Scale (RMDQ), the Oswestry Disability Questionnaire (ODI) and a pain numerical rating scale (NRS) (Spearman's correlations). RESULTS: It took one month to develop a consensus-based version of the QBPDS-I. The questionnaire was administered to 201 subjects with chronic LBP and was well accepted. EFA suggested a one-factor 20-item solution (first factor variance explained = 54.7%). Internal consistency (α = 0.95) and test-retest reliability (ICC = 0.90) were excellent. The MDC was 12 scale points. Construct validity was good as all of the hypotheses were met; correlations: RMDQ (r = 0.40), ODI (r = 0.48) and NRS (r = 0.44). CONCLUSIONS: The QBPDS-I is unidimensional, reliable and valid in patients with chronic LBP. Its use is recommended for clinical and research purposes.

The 88-item Multiple Sclerosis Spasticity Scale: a Rasch validation of the Italian version and suggestions for refinement of the original scale.

BACKGROUND: In multiple sclerosis (MS), the impact of spasticity on the patient's life is a key issue, and it is fundamental that existing tools measuring the patient's perspective undergo psychometric analysis and refinement to optimize confidence in their use in clinical practice and research. OBJECTIVE: We examined-by Rasch analysis (RA)-the main metric characteristics of the 88-item Multiple Sclerosis Spasticity Scale (MSSS-88) to: (i) further validate its Italian version (MSSS-88-IT), previously validated through classical test theory methods only and (ii) independently verify the measurement properties of the original scale. METHODS: MSSS-88 data from a convenience sample of 232 subjects with MS underwent RA, mainly examining item fit, reliability indices, test information function, dimensionality, local item independence, and differential item functioning (DIF). RESULTS: Most items fitted the Rasch model, but 13/88 items showed a misfit in infit and/or outfit values. Rasch reliability indices were high (> 0.80). Test information functions in most subscales showed a sharp decrease in measurement precision as the ability level departs from the quite limited central range of maximal information. The unidimensionality of each subscale was confirmed. Thirteen item pairs showed local dependency (residual correlations > 0.30) and three items presented DIF. CONCLUSION: Reliability, dimensionality and some internal construct validity characteristics of the MSSS-88-IT were confirmed. But, drawbacks of the original MSSS-88 emerged related to some item misfit, redundancy, or malfunctioning. Thus, further large independent studies are recommended, to verify the robustness of previous findings and examine the appropriateness of a few targeted item replacements.

Classical test theory and Rasch analysis validation of the Upper Limb Functional Index in subjects with upper limb musculoskeletal disorders.

OBJECTIVE: To perform a comprehensive analysis of the psychometric properties and dimensionality of the Upper Limb Functional Index (ULFI) using both classical test theory and Rasch analysis (RA). DESIGN: Prospective, single-group observational design. SETTING: Freestanding rehabilitation center. PARTICIPANTS: Convenience sample of Italian-speaking subjects with upper limb musculoskeletal disorders (N=174). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The Italian version of the ULFI. Data were analyzed using parallel analysis, exploratory factor analysis, and RA for evaluating dimensionality, functioning of rating scale categories, item fit, hierarchy of item difficulties, and reliability indices. RESULTS: Parallel analysis revealed 2 factors explaining 32.5% and 10.7% of the response variance. RA confirmed the failure of the unidimensionality assumption, and 6 items out of the 25 misfitted the Rasch model. When the analysis was rerun excluding the misfitting items, the scale showed acceptable fit values, loading meaningfully to a single factor. Item separation reliability and person separation reliability were .98 and .89, respectively. Cronbach alpha was .92. CONCLUSIONS: RA revealed weakness of the scale concerning dimensionality and internal construct validity. However, a set of 19 ULFI items defined through the statistical process demonstrated a unidimensional structure, good psychometric properties, and clinical meaningfulness. These findings represent a useful starting point for further analyses of the tool (based on modern psychometric approaches and confirmatory factor analysis) in larger samples, including different patient populations and nationalities.

Searching for optimal rating scales in the Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI).

The comparison of the performance of the numerical rating scale (NRS) versus visual analog scale (VAS) in the Bath Ankylosing Spondylitis Functional Index (BASFI) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) showed that the 11-point NRS is psychometrically superior to the 10-cm VAS. This finding is in agreement with previous studies and the recommendation by the Assessment of SpondyloArthritis international Society. To illustrate the functioning of the response categories of both BASFI and BASDAI, we analyzed the rating scales (using the Rasch rating scale model) in patients with ankylosing spondylitis. Our results have shown that the 11 categories available in the 0-10 NRS version of both BASFI and BASDAI exceed the number of levels of a construct that participants can discriminate. This indicates the need for improving the metric quality of both rating scales by appropriately reducing the number of categories.

Rasch validation of the German version of the Prosthesis Embodiment Scale for lower limb amputees and proposal of a revised version.

PURPOSE: To perform a detailed psychometric Rasch analysis of the Prosthesis Embodiment Scale (PEmbS) administered in adults with lower limb amputation (LLA). METHODS: A convenience sample of German-speaking adults with LLA (n = 150), recruited from German state agencies' databases, was asked to complete the PEmbS, a 10-item patient-reported scale assessing prosthesis embodiment. RESULTS: The local dependency between two items was resolved by keeping for the global score only the lower score of these two items (#9 and #10). Collapsing the seven response categories to four (two expressing disagreement and two agreement) eliminated disordered thresholds. After that, the PEmbS demonstrated unidimensionality, acceptable item fit, and good reliability indices. A keyform plot was created to transform raw scores into linear measures of prosthesis embodiment, making it possible to compare the individual's item responses with those expected by the Rasch model, and to manage missing responses. CONCLUSIONS: The PEmbS is useful for assessing prosthesis embodiment in people with LLA, both for research and clinical purposes. We propose a revised version of the PEmbS for lower limb amputees; its appropriateness in other LLA contexts requires further investigation.

Prosthesis embodiment has been empirically related to positive clinical outcomes in limb amputees.The Prosthesis Embodiment Scale (PEmbS) is a patient-reported scale that has been recently recommended for use in research on prosthesis embodiment.Rasch analysis showed that the revised version of the German PEmbS is a psychometrically sound instrument for the assessment of prosthesis embodiment in lower limb amputees.The PEmbS thus also allows reliable and valid diagnosis of prosthesis embodiment in clinical and rehabilitation contexts.

Evidence of multidimensionality in the ALSFRS-R Scale: a critical appraisal on its measurement properties using Rasch analysis.

OBJECTIVE: To examine dimensionality, reliability and validity of the Amyotrophic Lateral Sclerosis Functional Rating Scale-revised (ALSFRS-R) using traditional classical test theory methods and Rasch analysis in order to provide a rationale for possible improvement of its metric quality. METHODS: Methodological research on ALSFRS-R collected in a consecutive sample of 485 patients with amyotrophic lateral sclerosis (ALS) attending three tertiary ALS centres. RESULTS: The ALSFRS-R items showed good internal consistency but dimensionality analysis argues against the use of ALSFRS-R as a single score because the scale lacks unidimensionality. Parallel analysis and exploratory factor analysis revealed three factors representing the following domains: (1) bulbar function; (2) fine and gross motor function; and (3) respiratory function. Rasch analysis showed that all items in each domain fitted the respective constructs to measure, except for item No 9 'climbing stairs' and item No 12 'respiratory insufficiency'. Rating categories did not comply with the criteria for category functioning. Collapsing the scale's 5 level ratings into 3 levels improved its metric quality. CONCLUSIONS: The ALSFRS-R fails to satisfy rigorous measurement standards and should be, at least in part, revised. At present, ALSFRS-R should be considered as a profile of mean scores from three different domains (bulbar, motor and respiratory functions) more than a global total score. Further studies on ALSFRS-R using modern psychometric methods are warranted to confirm our findings and refine the metric quality of this scale, through a step by step process.

Psychometric characteristics of the Italian version of the revised Fibromyalgia Impact Questionnaire using classical test theory and Rasch analysis.

OBJECTIVES: The aim of this study was to perform a psychometric analysis of the Italian Fibromyalgia Impact Questionnaire Revised version (FIQR), using both classical test theory (CTT) and Rasch analysis (RA) in order to better analyse its construct validity and provide a rational basis for a possible improvement of its metric quality. METHODS: The study involved 503 patients with fibromyalgia (FM) (423 women and 80 men) with mean age of 51.3±10.1 years (range 19-74) and mean duration of symptoms of 11.1±8.7 years (range 1-30). All patients completed the Italian FIQR during their clinical visit. The translation and cultural adaptation process of the Italian FIQR followed the published guidelines and no local adjustments were made except for a slight adaptation of item 13 related to 'energy'. RESULTS: Factor Analysis revealed two salient dimensions: function (items 1-9) and symptoms (items 12-21). RA was thus performed on these two subscales. Rating scale diagnostics suggested collapsing the eleven rating categories of the scale into five. After combining these rating categories, RA showed that most items of each of the two subscales fitted the respective constructs to measure (MnSq 0.7-1.3). The reliability levels of the two subscales were higher than 0.80. CONCLUSIONS: This study provides psychometric evidence of the reliability, internal validity and two-dimensional structure of the FIQR in a FM population. Our results support the use of two separate subscales for 'function' and 'symptoms', and provide a useful starting point for further refinement of the scale.

Rasch analysis of the 22 knee injury and osteoarthritis outcome score-physical function items in Italian patients with knee osteoarthritis.

OBJECTIVES: To replicate previous Rasch analysis (RA) that yielded the 7-item Physical Function Short Form of the Knee Injury and Osteoarthritis Outcome Score (KOOS-PS7) in order to verify the consistency of the item selection process, and to analyze its main psychometric properties in a sample of Italian patients with osteoarthritis (OA). DESIGN: Methodological research on cross-sectional data from a convenience sample. SETTING: University hospital. PARTICIPANTS: Outpatients with symptomatic OA of the knee (N=200; women, 73%; mean age, 69.4y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: The KOOS-PF22 (22 items comprising the 2 KOOS domains of activities of daily living and sport/recreation). Its dimensionality was investigated using exploratory factor analysis. RA was performed on KOOS-PF22, KOOS-PS7, and an item set (called KOOS-PS12) obtained by removing from KOOS-PF22 all misfitting items. RESULTS: KOOS-PF22 showed a 2-factor structure, with the first one largely prevailing. Ten of its 22 items did not fit the Rasch model, while item dependency was present in 7 item pairs. Five of 7 KOOS-PS7 items and all KOOS-PS12 items showed acceptable fit to the Rasch model. The person separation reliability was .79 for KOOS-PS7 and .90 for KOOS-PS12; Cronbach alpha was .81 for KOOS-PS7 and .92 for KOOS-PS12. CONCLUSIONS: RA was not able to replicate the selection process of the items included in KOOS-PS7. KOOS-PS7 reliability levels indicate that the instrument seems more useful for group decisions than for everyday clinical application in single patients. To achieve a short form of KOOS-PF22 valid for a wide spectrum of individuals with knee OA, further psychometric studies are warranted.

The Functional Dexterity Test: test-retest reliability analysis and up-to date reference norms.

STUDY DESIGN: Clinical measurement. INTRODUCTION: Among the available tests for fine finger dexterity, the Functional Dexterity Test (FDT) has been indicated as a valid instrument to measure outcome in different conditions. PURPOSE OF THE STUDY: To analyze test-retest reliability, to study the influence of gender, age and hand dominance on the FDT score, and to collect reference norms for adult and elderly age-groups. METHODS: Test-retest reliability was calculated with the Intraclass Correlation Coefficient (ICC) and Standard Error of Measurement (SEM) in a subgroup of 324 healthy volunteers. An enlarged sample of 698 subjects, tested at least once, was used to present stratified data for age group, sex, and hand dominance, and ANOVA was used to investigate statistically significant differences between groups. RESULTS: The FDT showed excellent reliability (ICC > 0.90; SEM: <2 s for net times; <3 s for total scores). Age, gender and hand dominance significantly influenced FDT scores (p < 0.05), but no interaction between variables was found. CONCLUSIONS: FDT is confirmed as reliable, and up-to-date reference norms over a broad range of ages of the Italian adult population have been provided. LEVEL OF EVIDENCE: NA.

Head-to-head Rasch comparison of the Prosthesis Evaluation Questionnaire-Mobility Section and the Prosthetic Mobility Questionnaire 2.0 in Italian lower-limb prosthesis users.

BACKGROUND: The Prosthesis Evaluation Questionnaire-Mobility Section (PEQ-MS) and the Prosthetic Mobility Questionnaire (PMQ 2.0) are two validated self-report questionnaires assessing mobility in people with lower-limb amputation. OBJECTIVE: The aim of this study was to assess and compare the psychometric properties of PEQ-MS and PMQ 2.0 in a sample of 100 Italian lower-limb prosthesis users. METHODS: We conducted a secondary Rasch analysis of data from a prospective single-group observational study, comparing the PEQ-MS and PMQ 2.0 head to head and then cocalibrating them onto a common interval-scaled metric, through common-person equating, to compare their operational range. RESULTS: The PMQ 2.0 showed good measurement qualities. The PEQ-MS had acceptable psychometric properties, despite some weakness in item selection. Cocalibration of the two questionnaires indicated that they assess the same underlying construct (prosthetic mobility), but PMQ 2.0 items have a wider range of difficulty (by one logit). Finally, we created a nomogram allowing to "cross-walk" between scores of the two questionnaires. CONCLUSIONS: Comparison of the two questionnaires showed that the PMQ 2.0 has a better measurement performance and larger operational range than the PEQ-MS, making it more suitable for assessing lower-limb prosthesis users with a large range of locomotor abilities, in particular those with higher mobility levels.

Assessing individual-level measurement precision of the Short Physical Performance Battery using the test information function.

The Short Physical Performance Battery (SPPB) is a commonly used tool to assess lower extremity function, composed of three assessments (standing balance, gait speed, and chair stand). While its validity for group-level decisions has been positively demonstrated, the measurement precision at the individual level needs more clarification. We aimed to examine the SPPB's psychometric characteristics including its conditional measurement precision with Rasch methods in a sample of elderly patients admitted to cardiac rehabilitation. We analyzed prospectively collected SPPB data from 637 patients aged ≥75 years, admitted to our cardiac rehabilitation department (January 2018-July 2019). After classical Rasch analysis, we calculated the test information function to examine the measurement precision of the SPPB along the score continuum. The mean SPPB score was 6.3 points (SD 3.4) (potential range 0-12). Our results confirmed the SPPB unidimensionality (variance attributable to the main factor: 84.8%), appropriate functioning of rating scale categories, internal construct validity (infit and outfit mean-square statistics: 0.90-1.09), and no item local dependence (residual correlations <0.2). However, the measurement precision at the individual level was quite limited (SE > 0.94 logits): the confidence intervals for true scores were, at best, about one-third of the score range (four points). This limited measurement precision increases the risk of inappropriate clinical decisions about individuals in diagnostic classification or change assessment. Therefore, further research of high methodological quality is warranted on this point. Moreover, a clearer distinction between group-level vs. individual-level indicators of change is necessary.

Rasch validation of the German translation of the Prosthetic Limb Users Survey of Mobility short forms in people with lower limb amputation.

BACKGROUND: Prostheses are a primary rehabilitative intervention for people after lower limb amputation. To appropriately measure the effectiveness of prosthetic interventions, valid and reliable measures of prosthetic mobility are required. The Prosthetic Limb Users Survey of Mobility (PLUS-M) is a promising instrument for measuring prosthesis users' mobility. However, German translations of the PLUS-M short forms have not yet been validated. OBJECTIVES: Rasch validation of the German translation of the PLUS-M short forms in people with lower limb amputation. STUDY DESIGN: This study is based on a cross-sectional survey of prosthesis-using lower limb amputees from a nation-wide cohort. METHODS: PLUS-M data (the 7-item and the 12-item shortforms; PLUS-M-7 and PLUS-M-12, respectively) from 194 lower limb prosthesis users were subjected to Rasch analysis, an advanced statistical method for assessing if the measurement properties of a questionnaire comply with a wide spectrum of psychometric requirements. RESULTS: Analysis showed appropriate rating scale functioning, good internal construct validity (item fit), unidimensionality, and good targeting of the PLUS-M-7 and PLUS-M-12 short forms. Moreover, the greater conditional measurement precision of PLUS-M-12 (regarding higher test information and lower standard error of mobility estimates) was quantified. CONCLUSIONS: Rasch analysis of the German translation of both PLUS-M short forms showed good psychometric qualities. In addition, our study showed that test scores from the PLUS-M-12 are more accurate. Therefore, the PLUS-M-12 is recommended for individual-level clinical applications (e.g., classification or change assessment).

Rasch validation and refinement of the Lymphedema Life Impact Scale version 2 in an Italian cohort with secondary lymphedema.

PURPOSE: To produce and validate an Italian version of the Lymphedema Life Impact Scale version 2 (LLISv2-It), a tool measuring the impact of lymphedema on health-related quality of life, and investigate its main psychometric characteristics. METHODS: After translation and cross-cultural adaptation of the LLISv2, we administered it to 156 subjects with secondary lymphedema (upper or lower limb), together with (depending on the limb involved) either the Disabilities of the Arm, Shoulder and Hand questionnaire (DASH) or the Lower Extremity Functional Scale (LEFS). We analyzed the performance of LLISv2-It using Classical Test Theory and Rasch methods. RESULTS: Cronbach alpha was 0.89. Item fit statistics indicated that item #12 was underfitting (Infit MnSQ = 1.56; Outfit MnSq = 1.75). Test-retest reliability of the 17-item version (without item #18, not scored, according to the original authors) and of a 16-item version (without #12 and #18-a unidimensional item set) were both excellent (ICC2.1 = 0.93; 95%). The minimum detectable change was 8.9 points. The correlation of LLISv2-It with DASH and LEFS was r = 0.81 and -0.57, respectively. CONCLUSIONS: The Italian version of the LLISv2 is reliable and valid. To make the tool more psychometrically sound, we recommend to not calculate items #12 and #18 in the total score.IMPLICATIONS FOR REHABILITATIONThe Lymphedema Life Impact Scale (LLISv2) is particularly useful as a validated condition-specific health-related quality of life measure for patients with chronic edema/lymphedema. We have validated its Italian version (LLISv2-It).We also examined the psychometric properties of the LLISv2 in individuals with secondary lymphedema of either upper or lower limb, using both classical test theory and Rasch techniques, to provide insights for further refinement of the questionnaire.Based on our results, we recommend not to count item #12 in the total score (besides #18, as already suggested by the original authors). Moreover, we determined that the minimum detectable change of the LLISv2 was 9 points. This information is helpful in clinical practice to understand if the change in score is not due to chance (measurement error).Although further research is warranted, the present validation study of the LLISv2 increases the confidence in the metric quality and clinical utility of the scale to assess lymphedema-specific health-related quality of life in individuals with secondary lymphedema of either upper or lower limb.

Categorization and recommendations for outcome measures for lower limb absence by an expert panel.

BACKGROUND: Understanding the psychometric strengths and limitations of outcome measures for use with people with lower limb absence (LLA) is important for selecting measures suited to evaluating patient outcomes, answering clinical and research questions, and informing health care policy. The aim of this project was to review the current psychometric evidence on outcome measures in people with LLA to determine which measures should be included in a stakeholder consensus process. METHODS: An expert panel was assembled, and a 3-stage review process was used to categorize outcome measures identified in a systematic literature review into 3 distinct categories (recommended for measures with better than adequate psychometric properties; recommended with qualification; and unable to recommend). Panelists were asked to individually categorize measures based on results of a systematic review of identified measures' psychometric properties. Each measure's final categorization was based on ≥70% agreement by all panelists. RESULTS: No outcome measure attained the ≥70% consensus threshold needed to achieve a rating of "recommend." Hence, panelists suggested combining "recommend" and "recommend with qualifications" into a single category of "recommend with qualifications." Using this approach, consensus was reached for 59 of 60 measures. Consensus could not be reached on 1 outcome measure (socket comfort score). Thirty-six outcome measures were categorized as "unable to recommend" based on available evidence; however, 23 (12 patient-reported measures and 11 performance-based measures) demonstrated adequate psychometric properties in LLA samples and were thus rated as "recommend with qualification" by the expert panel. The panel of experts were able to recommend 23 measures for inclusion in the subsequent stakeholder review. A key strength of this process was bringing together international researchers with extensive experience in developing and/or using LLA outcome measures who could assist in identifying psychometrically sound measures to include in a subsequent stakeholder consensus process. CONCLUSION: The above categorizations represent the current state of psychometric evidence on outcome measures for people with LLA and hence may change over time as additional research becomes available. The results will be used to achieve wider consensus from clinicians, health policymakers, health clinic managers, researchers, and end users (i.e., individuals with LLA) on outcome measures for the International Society of Prosthetics and Orthotics lower limb Consensus Outcome Measures for Prosthetic and Amputation ServiceS.

Measurement precision of the Pain Catastrophizing Scale and its short forms in chronic low back pain.

The Pain Catastrophizing Scale (PCS) is a widely studied tool to assess pain catastrophizing for chronic low back pain (LBP). Short forms of the PCS exist, but their measurement precision at individual level is unclear. This study aimed to analyze the Rasch psychometric characteristics of the PCS and three of its short forms (two 4-item and one 6-item) in a sample of 180 Italian-speaking patients with chronic LBP, and compare their measurement precision at the individual level. We performed a Rasch analysis on each version of the PCS and calculated test information functions (TIFs) to examine conditional measurement precision. Rasch analysis showed appropriate rating category functioning, unidimensionality, and acceptable fit to the Rasch model for all PCS versions. This represented a prerequisite for performing further advanced psychometric analyses. According to TIFs, the PCS full scale showed-at any score level-higher measurement precision in estimating individual pain catastrophizing than its short forms (which had unacceptably high standard errors of measurement). Our results show acceptable conditional precision of the PCS full scale in estimating pain catastrophizing. However, further studies are needed to confirm its diagnostic accuracy at individual level. On the other hand, the study warns against use of the three PCS short forms for clinical decision-making at the individual level.

Responsiveness and Minimal Important Change of the Quebec Back Pain Disability Scale in Italian patients with chronic low back pain undergoing multidisciplinary rehabilitation.

BACKGROUND: There is still a lack of information concerning Minimal Important Change (MIC) of the Quebec Back Pain Disability Scale (QBPDS), that limits its use for clinical and research purposes. AIM: Evaluating responsiveness and MIC of the QBPDS in Italians with chronic low back pain (LBP). DESIGN: This is a methodological research based on an observational study. SETTING: Outpatient rehabilitation hospital. POPULATION: Two hundred and one patients with chronic LBP. METHODS: At the beginning and end of a multidisciplinary rehabilitation program, patients completed the QBPDS. At the end of treatment, they completed a 7-level global perceived effect (GPE) scale, which was split to obtain a dichotomous outcome (improved vs. stable). Responsiveness was calculated by distribution-based (effect size [ES]; standardized response mean [SRM]; minimum detectable change [MDC95]) and anchor-based methods (receiver operating characteristics [ROC] curves). ROC curves were also used to compute the MIC (based on QBPDS change score, both absolute and expressed as percentage). Correlations between the change score of the QBPDS and GPE were calculated. RESULTS: The ES was 0.29, the SRM was 0.43, and the MDC95 was 12 points. ROC analysis of the absolute change scores showed a MIC value of 6 points, with an area under the curve (AUC), sensitivity, and specificity of 0.83 (95% CI: 0.77-0.90), 77.7% and 80.8%, respectively. ROC analysis based on the percent change score from baseline revealed a MIC of 18% with an AUC, sensitivity and specificity of 0.85 (95% CI: 0.79-0.91), 80.6% and 80.8%, respectively. Correlation between change score of the QBPDS and GPE was ρ=-0.67. CONCLUSIONS: The QBPDS score change (expressed in both absolute value and percentage from baseline) was sensitive in detecting clinical changes in Italian subjects with chronic LBP undergoing multidisciplinary rehabilitation. In clinical practice, where absolute change is lower than MDC we recommend to rely on the MIC taking into account the percentage change from baseline condition. CLINICAL REHABILITATION IMPACT: The present study investigated the responsiveness and MIC of the QBPDS in a group of patients with chronic LBP. Our findings showed that the QBPDS score may classify with good to excellent discriminatory accuracy subjects who consider themselves as improved. Where examining change, we recommend considering both MICs we provided (expressing score change both in absolute value and as a percentage from baseline), and disregard values lower than MDC95, not being discernible from measurement error.