title: Development and validation of a muscular dystrophy-specific functional rating scale.
abstract: OBJECTIVE
  To develop a reliable and valid new rating scale for measuring the functional impact of muscular dystrophy.
  
  
  METHODS
  Prospective and longitudinal investigation.
  
  
  METHODS
  Three academic medical centres in Taiwan and the Muscular Dystrophy Association of Taiwan.
  
  
  METHODS
  The Brooke Scale, the Vignos Scale, the Barthel Index, muscular strength, contracture severity, and predicted forced vital capacity (FVC%).
  
  
  METHODS
  Scale development was in three stages. In stage I, a preliminary pool of 53 items was generated from patient interviews (n = 25), literature review, existing functional rating scales and expert opinion. In stage II, these items were administered to 85 patients with muscular dystrophy. The resulting data were analysed to construct a rating scale (the Muscular Dystrophy Functional Rating Scale, MDFRS) that encompassed four unidimensional constructs: mobility, basic activities of daily living, arm function and impairment. In stage III, the measurement properties of this rating scale were assessed in 121 muscular dystrophy patients different from those examined with the preliminary instrument.
  
  
  RESULTS
  Internal consistency reliability was excellent for all domains of the final 33-item scale, with values of Cronbach's alpha ranging from 0.84 to 0.97. Intraclass correlation coefficients for test-retest and inter-rater reliability were 0.99 for all domains of the MDFRS. The MDFRS showed moderate to high correlations with a range of functional rating scales measuring similar aspects and impairment parameters (Spearman's rho = 0.65-0.91; P < 0.001, each). Confirmatory factor analysis supported a unitary construct of the four-dimensional MDFRS. The MDFRS had small floor and ceiling effects in the study samples. Sensitivity to change was confirmed by large standardized response means for the MDFRS total score.
  
  
  CONCLUSIONS
  The MDFRS is a reliable and valid disease-specific measure of functional status for patients with muscular dystrophy.
authors.affiliation: Faculty of Physical Therapy, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan. yijilu@cc.kmu.edu.tw
authors.forename: Yi-Jing
authors.initials: YJ
authors.lastname: Lue
authors.forename: Chwen-Yng
authors.initials: CY
authors.lastname: Su
authors.forename: Rei-Cheng
authors.initials: RC
authors.lastname: Yang
authors.forename: Wei-Lieh
authors.initials: WL
authors.lastname: Su
authors.forename: Yen-Mou
authors.initials: YM
authors.lastname: Lu
authors.forename: Rong-Fong
authors.initials: RF
authors.lastname: Lin
authors.forename: Shun-Sheng
authors.initials: SS
authors.lastname: Chen
mesh_terms: D000203:Activities of Daily Living; D000293:Adolescent; D000328:Adult; D001132:Arm / Q000503:physiopathology; D002648:Child; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009119:Muscle Contraction / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D009136:Muscular Dystrophies / Q000503:physiopathology*; D011446:Prospective Studies; D011594:Psychometrics; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D014797:Vital Capacity / Q000502:physiology