Content Validity of a Comprehensive Physiotherapy Protocol for Children with Spastic Diplegic Cerebral Palsy Across GMFCS Levels: A Cross-sectional Study

Introduction: Children with spastic diplegic cerebral palsy present with multidomain functional limitations that require structured physiotherapy interventions tailored to Gross Motor Function Classification System (GMFCS) levels. Establishing content validity is essential to ensure that such protocols are clear, relevant, and clinically appropriate. Aim: To establish the content validity of a multidomain physiotherapy protocol developed for children across GMFCS levels I-V. Materials and Methods: A cross-sectional methodological content validation study was conducted at the Department of Physiotherapy, Ravi Nair Physiotherapy College, Datta Meghe Institute of Higher Education and Research, Wardha, Maharashtra, India, from June 2025 to November 2025. A comprehensive multidomain physiotherapy protocol comprising 30 items across Stability, Mobility, Strength, Endurance, Cognitive, and Respiratory domains for GMFCS levels I-V was evaluated. Nine experts in paediatric neurorehabilitation independently rated each item for relevance, clarity, and appropriateness using a four-point ordinal scale. Quantitative content validity analysis was performed by calculating the Item-level Content Validity Index (I-CVI) and Scale-level Content Validity Indices (S-CVI/ AVE and S-CVI/UA). Results: The I-CVI values ranged from 0.78 to 1.00 across domains. S-CVI/AVE values demonstrated high agreement (0.89-1.00). While most S-CVI/UA values ranged from 0.80 to 1.00, a lower S-CVI/UA value of 0.40 was observed as an outlier in the respiratory domain, reflecting partial lack of universal agreement among experts. Conclusion: The developed physiotherapy protocol demonstrated excellent content validity, supporting its clarity, relevance, and clinical appropriateness for use across all GMFCS levels.