HOW DO CHANGES IN IMPAIRMENT, ACTIVITY AND PARTICIPATION RELATE TO EACH OTHER IN CHILDREN WITH CEREBRAL PALSY?

Objectives: Rehabilitation has broadened to incorporate outcomes representing the ICF framework's levels of 'impairment', 'activity' and 'participation'. Moderate associations have been demonstrated between measures in different ICF levels at a single time, but change score relationships are unknown. This study evaluated these change score relationships within the context of a Botulinum Toxin-A (BT-A) injection intervention.

Methods: A repeated measures, one-group mixed-methods study evaluated associations between changes in impairment, activity and participation 2-month (m) and 6 m after lower extremity Bt-A (an intervention that reduces spasticity). Validated measures included: Tardieu spasticity scale and timed walk ('impairment'); Gross Motor Function Measure [GMFM] and Pediatric Evaluation of Disability Inventory [PEDI] ('activity'); and Pediatric Society of North America questionnaire [POSNA] ('participation'). Analysis of variance and linear regression techniques were used. Predictors included outcome measure baseline and change scores, age and Gross Motor Function Classification Level. A qualitative component involved mothers' interviews for perspectives on outcomes.

Results: Thirty-five ambulatory children with CP and parents completed baseline, 2 m and 6 m assessments. At 2 m post-Bt-A, there were statistically significant gains in 'activity' and 'participation' alongside spasticity reduction in gastrocnemius and hamstring muscles. Function was sustained or improved at 6 m despite recurring spasticity. Baseline relationships were fair to strong for impairment vs. GMFM, PEDI and POSNA, and strong between GMFM, PEDI and POSNA scores. Associations between change scores were fair at best. In each GMFM, PEDI and POSNA outcome model, predictors accounted for <60% of change score variation. Spasticity change accounted for <50% of explained variation. Mothers described similar patterns of impairment and functional change. While they believed that spasticity-reduction facilitated change, they were unsure how much it influenced skill gain and how much resulted from other factors.

Conclusion: Quantitative results and mothers' observations identified complex relationships between changes in impairment, activity and participation.