Path analysis of strength, spasticity, gross motor function, and health-related quality of life in children with spastic cerebral palsy

BACKGROUND: Measures of health-related quality of life may predict the future status of individuals with illnesses, and could therefore be a good indicator in children with cerebral palsy (CP). This study examines the causal relationship between spasticity, weakness, gross motor function, and health-related quality of life (QOL) in school-aged children with spastic CP and tests models of functional outcome mediated by gross motor function. METHODS: A total of 62 children (44 males, 18 females) with spastic CP were recruited. Strength was assessed with the Manual Muscle Test, spasticity with the Modified Ashworth Scale, and the Gross Motor Function Measure was also employed. Health-related QOL was assessed using the Korean version of the Childhood Health Assessment Questionnaire. Physical therapists interviewed the parents and assessed the children. RESULTS: The proposed path model showed good fit indices. The direct effects were significant between spasticity and gross motor function, strength and gross motor function, gross motor function and health-related QOL, and strength and health-related quality of life. Spasticity had a significant positive indirect effect and strength a significant negative indirect effect on health-related QOL through gross motor function. CONCLUSION: This is an initial study of the causal relationship between strength, spasticity, gross motor function, and health-related QOL.