title: Rasch validation of the Prosthetic Mobility Questionnaire: A new outcome measure for assessing mobility in people with lower limb amputation.
abstract: OBJECTIVE
  To create a new outcome measure of mobility in people with lower limb amputation, based on a pool of 14 items assessing prosthetic mobility, comprising the 12-item Prosthesis Evaluation Questionnaire (Mobility Section) plus 2 new items.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  A total of 100 subjects (median age 58 years; 46 males; median body mass index 23.8) who had recently undergone lower limb amputation.
  
  
  METHODS
  Each patient completed the 14-item questionnaire twice: (i) at admission to the rehabilitation unit for prosthetic rehabilitation training; (ii) at 6-month follow-up after discharge.
  
  
  RESULTS
  After Rasch analysis, 2 items were deleted (one due to misfit, the other because showing large (>  0.30) positive correlation of residuals with two other items (local dependence). The remaining items fitted the Rasch model (internal construct validity), giving a new 12-item scale with a 5-level response format, the Prosthetic Mobility Questionnaire (PMQ), which demonstrated unidimensionality, lack of differential item functioning, and good reliability indices (person-separation reliability = 0.87; Cronbach's alpha 0.88).
  
  
  CONCLUSIONS
  Although further studies are needed to increase confidence in clinical use of the PMQ, this new questionnaire appears to be a promising, psychometrically-sound patient-reported outcome measure for assessment of mobility in subjects with lower limb amputation who use a prosthesis.
authors.affiliation: , Scientific Institute of Veruno, Salvatore Maugeri Foundation, Via Revislate 13, IT-28010 Veruno (NO), Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Franchignoni
authors.forename: Marco
authors.initials: M
authors.lastname: Monticone
authors.forename: Andrea
authors.initials: A
authors.lastname: Giordano
authors.forename: Barbara
authors.initials: B
authors.lastname: Rocca
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000671:Amputation, Surgical / Q000534:rehabilitation*; D001186:Artificial Limbs; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D017063:Outcome Assessment, Health Care / Q000379:methods; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires