Translation and Psychometric Validation of an Italian Version of the Dance Functional Outcome Survey DFOS-IT

Study Overview
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Brief Summary
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Study Design: Evaluation of the psychometric properties of a translated, culturally adapted questionnaire. Objective: Translating, culturally adapting, and validating the Italian version of the Dance Functional Outcome Survey (DFOS-IT), allowing its use with Italian-speaking dancers to evaluate their musculoskeletal health and wellbeing inside and outside Italy. Summary of Background Data: Musculoskeletal injuries are a phenomenon of huge prevalence and has been a major focus within peer-reviewed literature since the 1980s. Growing attention is devoted to standardized outcome measures to improve interventions for injured dancers. A translated form of the DFOS, the only existing outcome measure that focus on the unique functional requirements of dancers, has never been validated within the Italian dancers population.

Detailed Description
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The DFOS is a dance-specific, lower extremity and low back functional outcome measure, the first and only existing at the moment. The DFOS-IT questionnaire will be developed involving forward-backward translation, a final re-evaluation made by a representative multidisciplinary expert committee and the realization of a prefinal version to establish a proper correspondence with the original English latest version. A factor analysis and analyses of internal consistency, construct validity, internal responsiveness and sensitivity will be conducted. The reliability will be measured for internal consistency (Cronbach α) and a factor analysis will be applied to analyse the internal structure. The divergent validity will be measured by comparing the data obtained from the compilation of the DFOS-IT with those of the SF-36 to evaluate the psychometric properties and the equivalence of the results adapted to the Italian language and culture. The validation of the psychometric properties of the instrument will start after it will been administered digitally, via a link to a website built using LimeSurvey, an application based on a MySQL database that allows the realization of online surveys, to a sample population of at least 140 dancers (10 subjects for each item of DFOS-IT) professionals or pre-professionals of age recruited through companies, professional academies, dance high schools and health professionals working with dancers. Through this link, from the time it will be online up to 30 September 2019, the dancers who will give their informed consent to their voluntary participation, will be able to access the online questionnaire. Upon enrollment, dancers will answer a demographics questionnaire, the DFOS-IT, and the SF-36. If they will take part in the reliability portion, then they filled out the DFOS-IT a second time within 4 to 9 days and, if in the responsiveness testing, a third time after 4-months. For the statistical analysis standard psychometric techniques will be used, such as reliability assessments, convergent and discriminant validity tests of each item and of the construct in its entirety, empirical validity tests in relation to the clinical status and formal tests to assess their accuracy to ends to test the hypotheses. The investigators hypothesize to be able to reproduce a tool that reflects the characteristics of the DOFS in the original language and therefore it will prove to have, even in its Italian version, an acceptable psychometric performance as an outcome and screening measure for dancers. The DFOS-IT will show to be a useful tool to monitor both healthy state and functional limitation following lower extremity or low back injury in adult ballet and modern dancers.

Official Title
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Traduzione, Adattamento Transculturale e Misura Delle proprietà Psicometriche Del Questionario Dance Functional Outcome Survey (Dfos) in Lingua Italiana

Conditions
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Injuries, Musculoskeletal Pain, Low Back Pain, Lower Limb Injury, Limitation, Mobility, Health Impairment

Participation Criteria
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Eligibility Criteria
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For all dancers, inclusion criteria : A minimum of 3 years of dance training (classical, contemporary, modern-jazz ..) An Intermediate to expert skill level 18 years of age or older For healthy dancers subgroup, inclusion criteria: - No low back or lower extremity injury in the previous 3 months. For injured dancers subgroup, inclusion criteria: - at least one low back or lower extremity injury in the previous 3 months. For all dancers exclusion criteria: Non-Italian speaking Pregnancy Current active disease processes other from a musculoskeletal injury in the low back or lower extremity.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healty Dancers<br>Healthy adult dancers | |
| Injured Dancers<br>Injured adult dancers | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dance Functional Outcome Score | Self-reported functional outcome questionnaire for ballet and modern dance populations, applicable to musculoskeletal injuries of the low back and lower extremities. The 14-question DFOS assesses the dancer's ability in areas of activities of daily living (ADL, 40 points) and dance technique (technique, 50 points). Total score from 0 to 90, subscore Activities of daily living 40, Technique 50. Higher scores represent better outcomes. Total points are normalized to a percentage, with 100% representing full function without limitations. | 1 day | 
| Validate the Italian translation of the DFOS | The score between the DFOS-IT versus the italian validated version of the SF-36 will be compared | 1 day | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| DFOS-IT test-retest reliability | Assess DFOS-IT test-retest reliabilty in adult dancers with and without musculoskeletal injury to the low back or lower extremities. Test-retest reliability will be assessed with 1 group (including healthy and injured dancers), 2 measurements (test-retest), with an effect size change of 0.25, power of 0.95, and a significance level of α = .05. Test-retest reliability analysis separately will compare combined, healthy, and injured groups for the DFOS total score and ADL and technique subscores using the intraclass correlation coefficient. The ICC values of 0.49 or less will be considered low, 0.50 to 0.69 moderate, 0.70 to 0.89 high, and 0.90 to 1.00 very high. | Baseline - Between Day 4 and 30 | 
| DFOS-IT construct validity | Assess DFOS-IT construct validity in with 1 group (adult dancers with and without musculoskeletal injury to the low back or lower extremities), with an effect-size change of 0.25, power of 0.95, and a significance level of α = .05. | Mid December 2019 | 
| DFOS-IT factor analysis and internal consistency | Assess DFOS-IT factor analysis and internal consistency in adult dancers with and without musculoskeletal injury to the low back or lower extremities. Cronbach's alpha will be calculate to estimate internal item consistency. | Mid December 2019 | 
| DFOS-IT sensitivity | Assess DFOS-IT sensitivity in adult dancers with and without musculoskeletal injury to the low back or lower extremities. To conduct sensitivity analyses in the healthy group and injured group, the researchers will conduct a t test for equal variances not assumed and a significant Levene test. | Mid December 2019 | 
| DFOS-IT Internal responsiveness | participants are classified as 'improved' (injured at T0 and healthy at T4mo), 'worsened' (healthy at T0 and injured at T4mo) or 'no change' (health status unchanged from T0 to T4mo). We will examine differences in DFOS-IT and SF-36 scores across 3-time-points using repeated-measures ANOVA. Internal responsiveness was defined using SEM, minimal detectable change at the 95%CI, standardized response mean and effect size and calculated for all DFOS-IT scores, SF-36 PCS and MCS. | After 4 months from the first submission | 
| DFOS-IT Floor and Ceiling Effects | Assess DFOS-IT Floor and Ceiling Effects in the injured group | Mid December 2019 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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dance, health, ballet, musculoskeletal injury, SF-36, wellness, dance medicine