Measuring the Reliability and Construct Validity of the Pediatric Evaluation of Disability Inventory–Computer Adaptive Test (PEDI-CAT) in Children With Cerebral Palsy

Abstract

ObjectiveThe purpose of this study was to (1) investigate the construct validity and (2) test-retest reliability of the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) in children with cerebral palsy (CP). DesignA prospective convenience cross-sectional sample. SettingMultidisciplinary CP clinic in a tertiary level pediatric children’s hospital. ParticipantsEnglish- and Spanish-speaking school-aged children (N=101) with a diagnosis of CP, stratified by Gross Motor Function Classification System level, who presented to our multidisciplinary clinic. Participants were excluded if they underwent recent surgery (<6mo) or botulinum neurotoxin A injection (<3mo). A subset of 17 families participated in retest reliability. Main Outcome MeasuresConvergent and divergent validity were evaluated using Spearman correlation coefficient analysis; test-retest reliability was assessed using intraclass correlation coefficients (ICCs). ResultsMean age was 12±3.7 years. Convergent validity was established between Mobility (PEDI-CAT) and Functional Mobility Scale (FMS) (5 m, r=0.85; 50 m, r=0.84; 500 m, r=0.76; P<.001). In ambulant children, convergent validity was established between Daily Activities (PEDI-CAT vs Pediatric Quality of Life CP [PedsQL-CP] [r=0.85, P<.001]) and between Social/Cognitive (PEDI-CAT) and Speech and Communication (PedsQL-CP) (r=0.42, P<.001). In nonambulant children, convergent validity was established between Daily Activities (PEDI-CAT) and Personal Care (Caregiver Priorities and Child Health Index of Life with Disabilities [CPCHILD]) (r=0.44, P<.001) and between social/cognitive (PEDI-CAT) and Communication (CPCHILD) (r=0.64, P<.001). A lack of correlation between Daily Activities, Social/Cognitive, and Responsibility (PEDI-CAT) and FMS and between the Mobility (PEDI-CAT) and Communication (PedsQL) domains confirmed divergent validity. Test-retest reliability was excellent for all domains of the PEDI-CAT (ICC=0.96-0.99). ConclusionsThe PEDI-CAT is an outcome measure that demonstrates strong construct validity and reliability in children with CP.