Validity, responsiveness, minimal detectable change, and minimal clinically important change of Pediatric Balance Scale in children with cerebral palsy

This study examined criterion-related validity and clinimetric properties of the pediatric balance scale (PBS) in children with cerebral palsy (CP). Forty-five children with CP (age range: 19-77 months) and their parents participated in this study. At baseline and at follow up, Pearson correlation coefficients were used to determine criterion-related validity by analyzing the correlation between the PBS, including PBS-static, PBS-dynamic, and PBS-total, and criterion measures, including the Gross Motor Function Measure-66 items (GMFM-66) and Functional Independence Measures for Children (WeeFIM). Responsiveness was examined by paired t test and by standardized response mean (SRM). The minimal detectable change (MDC) was analyzed at the 90% confidence level, and the minimal clinically important differences (MCID) was estimated by anchor-based and distribution-based approaches. The PBS with GMFM-66 and WeeFIM showed fair-to-excellent concurrent validity at pretreatment and follow up and predictive validity. The SRM values of all PBS scales were 0.75. For the PBS-static, PBS-dynamic, and PBS-total, the MDC90 values were 0.79, 0.96, and 1.59, and the MCID ranges were 1.47-2.92, 2.23-2.92, and 3.66-5.83, respectively. Improvement of at least MDC values on the PBS can be considered a true change, not measurement error. A mean change must exceed the MCID range on PBS to be considered clinically important change. Therefore, all PBS scales were moderately responsive to change. Clinicians and researchers can use these clinimetric data for PBS to determine if a change score represents a true or clinically meaningful effect at posttreatment and follow up. (C) 2012 Elsevier Ltd. All rights reserved.