title: Gross Motor Function Measure Evolution Ratio: Use as a Control for Natural Progression in Cerebral Palsy.
abstract: To develop a new way to interpret Gross Motor Function Measure (GMFM-66) score improvement in studies conducted without control groups in children with cerebral palsy (CP).
  
  
  
  The curves, which describe the pattern of motor development according to the children's Gross Motor Function Classification System level, were used as historical control to define the GMFM-66 expected natural evolution in children with CP. These curves have been modeled and generalized to fit the curve to particular children characteristics.
  
  
  
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  Assuming that the GMFM-66 score evolution followed the shape of the Rosenbaum curves, by taking into account the age and GMFM-66 score of children, the expected natural evolution of the GMFM-66 score was predicted for any group of children with CP who were <8 years old. Because the expected natural evolution could be predicted for a specific group of children with CP, the efficacy of a treatment could be determined by comparing the GMFM-66 score evolution measured before and after treatment with the expected natural evolution for the same period. A new index, the Gross Motor Function Measure Evolution Ratio, was defined as follows: Gross Motor Function Measure Evolution Ratio=measured GMFM-66 score change/expected natural evolution.
  
  
  
  For practical or ethical reasons, it is almost impossible to use control groups in studies evaluating effectiveness of many therapeutic modalities. The Gross Motor Function Measure Evolution Ratio gives the opportunity to take into account the expected natural evolution of the gross motor function of children with CP, which is essential to accurately interpret the therapy effect on the GMFM-66.
authors: Marie Enfant Rehabilitation Center, Sainte-Justine University Hospital Center, Montreal, QC, Canada.
authors: Pierre
authors: P
authors: Marois
authors: Department of Engineering Physics, École Polytechnique de Montréal, Montreal, QC, Canada.
authors: Mikael
authors: M
authors: Marois
authors: Marie Enfant Rehabilitation Center, Sainte-Justine University Hospital Center, Montreal, QC, Canada; Department of Physical Activity Sciences, Université du Québec à Montréal, Montreal, QC, Canada.
authors: Annie
authors: A
authors: Pouliot-Laforte
authors: Department of Neurological Sciences, Université de Montréal, Montreal, QC, Canada.
authors: Michel
authors: M
authors: Vanasse
authors: Department of Social and Preventive Medicine, School of Medicine, Université de Montréal, Montreal, QC, Canada.
authors: Jean
authors: J
authors: Lambert
authors: Marie Enfant Rehabilitation Center, Sainte-Justine University Hospital Center, Montreal, QC, Canada; Department of Physical Activity Sciences, Université du Québec à Montréal, Montreal, QC, Canada. Electronic address: laurent.ballaz@uqam.ca.
authors: Laurent
authors: L
authors: Ballaz
mesh_terms: D002547:Cerebral Palsy / Q000145:classification / Q000503:physiopathology / Q000628:therapy; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D004185:Disability Evaluation; D018450:Disease Progression; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009048:Motor Skills; D012720:Severity of Illness Index
keywords: Cerebral palsy; Child; Control groups; Motor skills disorders; Rehabilitation