Gross motor performance measure for children with cerebral palsy: study design and preliminary findings.

This project investigated the validity, reliability and responsiveness of the Gross Motor Performance Measure (GMPM). The GMPM was developed as an observational instrument to measure changes in quality of movement in children with cerebral palsy. Physical therapists from 3 children's treatment centres assessed 107 children with CP, 18 children with head injury and 33 non-disabled children. Assessments were conducted on 2 occasions, 4 to 6 months apart. The measurement protocol included assessment with the GMPM and the Gross Motor Function Measure (GMFM). Validity was tested by comparing changes in GMPM scores to parent and therapist independent ratings of the children's motor performance. Also, a sample (n = 30) of paired assessments was videotaped for 'masked' evaluation by therapists. Inter-rater, intra-rater and test-retest reliability studies (n = 30) were conducted. Responsiveness to change was determined through parent and therapist ratings of the importance of observed changes in quality of movement. Data collection for this study has just been completed. Validation hypotheses have been postulated regarding correlations between changes in GMPM scores; GMFM scores; age of children; diagnosis; severity of condition; parent, therapist and 'masked' evaluator judgement of change. Correlation analysis, t-test and analysis of variance results will be presented. Reliability data for the GMPM and parent/therapist rating scales will be presented using intra-class correlation coefficients. Data supporting responsiveness of the GMPM will be presented using an analysis of variance model for 'stable' and 'responsive' groups.