title: The Otitis Media-6 questionnaire: psychometric properties with emphasis on factor structure and interpretability.
abstract: BACKGROUND
  The Otitis Media-6 questionnaire (OM-6) is the most frequently used instrument to measure health related quality of life in children with otitis media. The main objectives of this study are 1) to translate and cross-culturally adapt the OM-6 into Danish, and 2) to assess important psychometric properties including structural validity and interpretability of the OM-6 in a Danish population of children suffering from otitis media.
  
  
  METHODS
  The OM-6 was translated and cross-culturally adapted according to international guidelines. A longitudinal validation study enrolled 491 children and their families, and the measurement properties of the OM-6 were evaluated using the Cosmin taxonomy. The properties assessed were construct and structural validity (confirmatory factor analysis) including internal consistency, reproducibility (test-retest reliability and smallest detectable change), responsiveness and interpretability.
  
  
  RESULTS
  A total of 435 children were eligible to participate in the study. Analyses of structural validity and internal consistency indicated that parent appraisal of hearing and speech problems may be problematic. Both scales showed similarly good test-retest reliability and construct validity, were able to discriminate between diagnostic subgroups and responsive to change. Cut-off values of 16.7 and 30.0 were found to represent minimal important change for the patients.
  
  
  CONCLUSIONS
  The Danish version of the OM-6 is a reliable, valid, responsive and interpretable questionnaire to measure quality of life in children with otitis media. This study sheds light on possible weaknesses of the instrument that needs to be acknowledged in the utilization of the instrument. However, despite these issues our results support the continuing use of OM-6 as a 1-factor functional health scale with a separate global health rating. Furthermore, indications of values representing minimal important change as perceived by the respondent are presented.
authors.affiliation: Department of ENT Head & Neck Surgery, Odense University Hospital, Odense C 5000, Denmark. chrheidemann@gmail.com.
authors.forename: Christian Hamilton
authors.initials: CH
authors.lastname: Heidemann
authors.forename: Christian
authors.initials: C
authors.lastname: Godballe
authors.forename: Anette Drøhse
authors.initials: AD
authors.lastname: Kjeldsen
authors.forename: Eva Charlotte Jung
authors.initials: EC
authors.lastname: Johansen
authors.forename: Christian Emil
authors.initials: CE
authors.lastname: Faber
authors.forename: Henrik Hein
authors.initials: HH
authors.lastname: Lauridsen
mesh_terms: D002648:Child; D002675:Child, Preschool; D054521:Cultural Competency; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010033:Otitis Media / Q000523:psychology*; D010290:Parents; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*