title: Psychometric properties of 3 patient-reported outcome measures for the assessment of shoulder disability after neck dissection.
abstract: BACKGROUND
  Patient-reported outcome measures evaluating shoulder disability after neck dissection have not been sufficiently validated. We assessed the psychometric properties of the Shoulder Disability Questionnaire (SDQ), Neck Dissection Impairment Index (NDII), and the Shoulder Pain and Disability Index (SPADI) in patients after neck dissection.
  
  
  METHODS
  One hundred seven patients completed the SDQ, NDII, and SPADI on 4 occasions over 6 months, and underwent physical examination. We assessed internal consistency, test-retest reliability, clinical and construct validity, and responsiveness to change. The possibility of combining the NDII and SPADI items into a single scale was explored by Rasch analysis.
  
  
  RESULTS
  All questionnaires exhibited good reliability and validity. We were successful in fitting a Rasch model to the data.
  
  
  CONCLUSIONS
  The results support the suitability of the SDQ, NDII, and the SPADI for use in neck dissection patients. Combining the SPADI and NDII in a single Rasch scale improves item difficulty distribution but reduces variability and discriminative ability.
authors.affiliation: Department of Physiotherapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands.|Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Martijn M
authors.initials: MM
authors.lastname: Stuiver
authors.affiliation: Department of Physiotherapy, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Marieke R
authors.initials: MR
authors.lastname: ten Tusscher
authors.affiliation: Department of Physiotherapy, Medical Centre Leeuwarden, Leeuwarden, The Netherlands.
authors.forename: Anita
authors.initials: A
authors.lastname: van Opzeeland
authors.affiliation: Department of Physiotherapy, Rijnstate Hospital, Arnhem, The Netherlands.
authors.forename: Wim
authors.initials: W
authors.lastname: Brendeke
authors.affiliation: Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Lindeboom
authors.affiliation: University of Groningen, University Medical Centre Groningen, Department of Rehabilitation and Department of Oral and Maxillofacial Surgery, Groningen, the Netherlands.
authors.forename: Pieter U
authors.initials: PU
authors.lastname: Dijkstra
authors.affiliation: Division of Psychosocial Research and Epidemiology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
authors.forename: Neil K
authors.initials: NK
authors.lastname: Aaronson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002278:Carcinoma in Situ / Q000601:surgery*; D003430:Cross-Sectional Studies; D005260:Female; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection / Q000009:adverse effects* / Q000379:methods; D009426:Netherlands; D009959:Oropharyngeal Neoplasms / Q000601:surgery; D010147:Pain Measurement; D063868:Patient Outcome Assessment; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D020069:Shoulder Pain / Q000175:diagnosis / Q000209:etiology*; D011795:Surveys and Questionnaires; D014062:Tongue Neoplasms / Q000601:surgery
keywords: Rasch model; head and neck neoplasms; reliability; shoulder disability; validity