title: The stability of the Manual Ability Classification System over time.
abstract: OBJECTIVE
  To evaluate the stability over time of the Manual Ability Classification System (MACS) levels.
  
  
  METHODS
  The study group comprised 1267 children with cerebral palsy (746 males, 521 females) who were followed from 2005 to 2010 with two or more registered MACS classifications rated at least 1 year apart. Thirty-five percent of the children (n=445) had four MACS registrations. The children were between 4 and 17 years old at their first rating, The stability over time was also compared between children who were younger (4y of age) or older (≥10y) at the time of their first classification.
  
  
  RESULTS
  An excellent stability was found between two ratings at 1-year intervals with an intraclass correlation coefficient (ICC) of 0.97 (95% CI 0.97-0.97) and 82% agreement (n=1267). The stability was also excellent for two ratings performed 3 to 5 years apart (ICC 0.96; 95% CI 0.95-0.97) with an agreement of 78% (n=445). Across four ratings, 70% of the children remained at the same level. The results were similar for younger and older children, indicating that stability was not influenced by age.
  
  
  CONCLUSIONS
  This study provides evidence that MACS levels are stable over time and that the classification has predictive value.
authors.affiliation: Department of Women's and Children's Health, Astrid Lindgren Children's Hospital, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ann-Marie
authors.initials: AM
authors.lastname: Öhrvall
authors.forename: Lena
authors.initials: L
authors.lastname: Krumlinde-Sundholm
authors.forename: Ann-Christin
authors.initials: AC
authors.lastname: Eliasson
mesh_terms: D000203:Activities of Daily Living / Q000145:classification; D000293:Adolescent; D000367:Age Factors; D001076:Aptitude; D002547:Cerebral Palsy / Q000145:classification* / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D019957:Motor Skills Disorders / Q000145:classification* / Q000175:diagnosis*; D009460:Neurologic Examination / Q000706:statistics & numerical data*; D015588:Observer Variation; D011594:Psychometrics; D015203:Reproducibility of Results; D013548:Sweden