title: Rasch analysis of the Neck Bournemouth Questionnaire to measure disability related to chronic neck pain.
abstract: OBJECTIVE
  To determine the psychometric properties of the Neck Bournemouth Questionnaire in patients with chronic neck pain, using Rasch analysis.
  
  
  METHODS
  A sample of 161 subjects with chronic neck pain was assessed with the Neck Bournemouth Questionnaire. Before performing Rasch analysis, we examined the structure of the scale with factor analysis. The goodness-of-fit of the data to the model, thresholds ordering, unidimensionality, local independence of the items, differential item functioning, person separation index, and mean person's location were assessed.
  
  
  RESULTS
  Both exploratory and confirmatory factor analyses supported the presence of 2 factors. Only Factor 1 needed a modification (item 7 removal) in order to achieve the fit to the Rasch model (χ2 = 10.65, df 8, p = 0.22). The person separation index was 0.80 and the mean location of persons 0.48 (standard deviation (SD) 1.02). Factor 2 (items 4 and 5) fitted the model without modifications (χ2 = 3.86, df 4, p = 0.42). Its person separation index and mean person's location were, respectively, 0.77 and -0.71 (SD 1.57).
  
  
  CONCLUSIONS
  The Neck Bournemouth Questionnaire with the purposed modification may provide useful clinical profiles and change scores of subjects with chronic neck pain for research purposes.
authors.affiliation: Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Campus of Savona, Savona, Italy. tommaso.geri@gmail.com.
authors.forename: Tommaso
authors.initials: T
authors.lastname: Geri
authors.forename: Daniele
authors.initials: D
authors.lastname: Piscitelli
authors.forename: Roberto
authors.initials: R
authors.lastname: Meroni
authors.forename: Francesca
authors.initials: F
authors.lastname: Bonetti
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Giovannico
authors.forename: Roberto
authors.initials: R
authors.lastname: Traversi
authors.forename: Marco
authors.initials: M
authors.lastname: Testa
mesh_terms: D002908:Chronic Disease; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019547:Neck Pain / Q000175:diagnosis*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011594:Psychometrics / Q000379:methods*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires