Predicting mobility gains among children with cerebral palsy after application of botulinum toxin A

Abstract

Background: Botulinum toxin A (BTA) is commonly used to treat children with cerebral palsy (CP). However, the variables measured before BTA application and associated with motor function and independent mobility, known as predictors of functional outcomes, have not been well defined. Objective: To identify clinical predictors of gains in functional motor skills and independence of mobility among children with CP, three and six months after BTA application. Methods: This was a convenience sample of children with spastic CP (n=35). Measurements of quantitative gains in motor skills and independence of mobility were taken three and six months after BTA application. These outcomes were observed through repeated applications of two functional tests: GMFM (Gross Motor Function Measure) and PEDI (Pediatric Evaluation of Disability Inventory). These tests evaluated gross motor function while sitting or standing and during transitions between these postures, and also during dynamic activities such as walking, running and jumping, along with the children's independence in mobility tasks. The independent variables included the children's characteristics such as age, severity, topographic diagnosis, neuromuscular-skeletal parameters (range of motion and spasticity), gait quality and performance in the functional tests before BTA. Results: Four predictive models were developed (R 2 between 0.58 and 0.83; p<0.05) through the use of CART analysis: two at three months and two at six months after BTA application. The results indicated that children with better gait quality, smaller repertoire of functional motor skills, less independence of locomotion and age below four years and six months before BTA presented greater gains in motor skills and independence in mobility. Conclusion: The results identified significant clinical parameters that can predict functional outcomes of BTA applications among children with CP.