title: Validation of the Charcot-Marie-Tooth disease pediatric scale as an outcome measure of disability.
abstract: OBJECTIVE
  Charcot-Marie-Tooth disease (CMT) is a common heritable peripheral neuropathy. There is no treatment for any form of CMT, although clinical trials are increasingly occurring. Patients usually develop symptoms during the first 2 decades of life, but there are no established outcome measures of disease severity or response to treatment. We identified a set of items that represent a range of impairment levels and conducted a series of validation studies to build a patient-centered multi-item rating scale of disability for children with CMT.
  
  
  METHODS
  As part of the Inherited Neuropathies Consortium, patients aged 3 to 20 years with a variety of CMT types were recruited from the USA, United Kingdom, Italy, and Australia. Initial development stages involved definition of the construct, item pool generation, peer review, and pilot testing. Based on data from 172 patients, a series of validation studies were conducted, including item and factor analysis, reliability testing, Rasch modeling, and sensitivity analysis.
  
  
  RESULTS
  Seven areas for measurement were identified (strength, dexterity, sensation, gait, balance, power, endurance), and a psychometrically robust 11-item scale was constructed (CMT Pediatric Scale [CMTPedS]). Rasch analysis supported the viability of the CMTPedS as a unidimensional measure of disability in children with CMT. It showed good overall model fit, no evidence of misfitting items, and no person misfit, and it was well targeted for children with CMT.
  
  
  CONCLUSIONS
  The CMTPedS is a well-tolerated outcome measure that can be completed in 25 minutes. It is a reliable, valid, and sensitive global measure of disability for children with CMT from the age of 3 years.
authors.affiliation: Children's Hospital at Westmead and University of Sydney, Australia. Joshua.Burns@health.nsw.gov.au
authors.forename: Joshua
authors.initials: J
authors.lastname: Burns
authors.forename: Robert
authors.initials: R
authors.lastname: Ouvrier
authors.forename: Tim
authors.initials: T
authors.lastname: Estilow
authors.forename: Rosemary
authors.initials: R
authors.lastname: Shy
authors.forename: Matilde
authors.initials: M
authors.lastname: Laurá
authors.forename: Julie F
authors.initials: JF
authors.lastname: Pallant
authors.forename: Monkol
authors.initials: M
authors.lastname: Lek
authors.forename: Francesco
authors.initials: F
authors.lastname: Muntoni
authors.forename: Mary M
authors.initials: MM
authors.lastname: Reilly
authors.forename: Davide
authors.initials: D
authors.lastname: Pareyson
authors.forename: Gyula
authors.initials: G
authors.lastname: Acsadi
authors.forename: Michael E
authors.initials: ME
authors.lastname: Shy
authors.forename: Richard S
authors.initials: RS
authors.lastname: Finkel
mesh_terms: D002607:Charcot-Marie-Tooth Disease / Q000150:complications* / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D004185:Disability Evaluation; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D012680:Sensitivity and Specificity