RESUMO
The Trunk Impairment Scale (TIS) is a valid and reliable tool to assess trunk impairment in children with heterogeneous cerebral palsy. The purpose of this study was to determine the reliability and validity of the TIS in assessing children with spastic diplegic cerebral palsy. The sample was a total of 30 subjects (15 = boys, 15 = girls). All subjects underwent an assessment of the sitting component of the Gross Motor Function Measure-88 and TIS by rater 1. Rater one observed video recordings within 24 h and scored TIS for intra-rater reliability, while rater two did likewise after 48 h for inter-rater reliability. The mean and standard deviation of the TIS and sitting components of the Gross Motor Function Measure-88 were 15.66 ± 4.20 and 52.36 ± 6.26, respectively. We established intra-rater and inter-rater reliability of the TIS with Intra Class Correlation Coefficient 0.991 and 0.972, respectively. The concurrent validity of the TIS with the sitting component of the Gross Motor Function Measure-88 was good, with an r-value of 0.844 (p < 0.001). This study showed the excellent intra-rater and inter-rater reliability and high concurrent validity of the TIS in assessing children with spastic diplegic cerebral palsy.