title: Improvement of a questionnaire measuring activity limitations in rising and sitting down in patients with lower-extremity disorders living at home.
abstract: OBJECTIVE
  To improve a self-administered questionnaire that includes 42 dichotomous items and measures activity limitations in rising and sitting down (R&S) in patients with lower-extremity disorders who live at home.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Outpatient clinics of secondary and tertiary care centers.
  
  
  METHODS
  Patients (N=759; 47% men; mean age +/- standard deviation, 60.7+/-15.2y) living at home, with lower-extremity disorders resulting from stroke, poliomyelitis, osteoarthritis, amputation, and complex regional pain syndrome type I.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  (1) Unidimensionality, indicating that items assess only a single construct; (2) fit with the one-parameter logistic model (OPLM), yielding information about patient and item location parameters; (3) intratest reliability, indicating consistency of patients' item scores; and (4) content validity, indicating completeness with which the items cover the important aspects of the construct that they are attempting to represent.
  
  
  RESULTS
  Thirty-nine of 42 items: (1) loaded on 1 component (variance explained, 59%; item component loadings, >or=.51), (2) showed good fit with the OPLM (P=.15), (3) had a good intratest reliability (Cronbach alpha=.96), and (4) had a good content validity (all important aspects represented).
  
  
  CONCLUSIONS
  A unidimensional scale that fits with the OPLM has been developed for measuring activity limitations in R&S in patients with lower-extremity disorders who live at home.
authors.affiliation: Department of Rehabilitation Medicine, Institute for Research in Extramural Medicine, VU University Medical Center, Amsterdam, The Netherlands. ld.roorda@vumc.nl
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
authors.forename: Ivo W
authors.initials: IW
authors.lastname: Molenaar
authors.forename: Gustaaf J
authors.initials: GJ
authors.lastname: Lankhorst
authors.forename: Lex M
authors.initials: LM
authors.lastname: Bouter
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D004188:Disarticulation; D005260:Female; D006801:Humans; D007866:Leg / Q000503:physiopathology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D015207:Osteoarthritis, Hip / Q000503:physiopathology; D011051:Poliomyelitis / Q000503:physiopathology; D011187:Posture / Q000502:physiology; D012019:Reflex Sympathetic Dystrophy / Q000503:physiopathology; D015203:Reproducibility of Results; D012111:Residence Characteristics; D020521:Stroke / Q000503:physiopathology; D011795:Surveys and Questionnaires