Evaluating the Discriminant Validity of the Pediatric Evaluation of Disability Inventory: Computer Adaptive Test in Children With Cerebral Palsy.

Background: The Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT) is a new clinical assessment for children and youth from birth through 20 years of age.

Objective: To determine the discriminant validity of the PEDI-CAT according to the Gross Motor Function Classification System (GMFCS) and Manual Ability Classification System (MACS) in children with cerebral palsy (CP).

Design: A prospective convenience cross-sectional sample of 101 school-age children with CP was stratified by GMFCS level.

Methods: Participants were excluded if they underwent recent surgery (<6 months). Receiver operating characteristics curve analysis was used to quantify the discriminant validity of the PEDI-CAT domains to distinguish the level of independence in fine and gross motor function. General linear modeling was used to assess discriminant ability across all GMFCS and MACS levels.

Results: Mean age was 11 years, 11 months (SD 3.7). Mobility and Daily Activities domains exhibited excellent discriminant validity distinguishing between ambulatory and nonambulatory participants [area under the curve (AUC) = 0.98 and 0.97, respectively] and the Daily Activities domain exhibited excellent discriminant validity distinguishing between independent and dependent hand function (AUC = 0.93). All PEDI-CAT domains were able to discriminate between ambulatory (GMFCS levels I-III) or nonambulatory (GMFCS levels IV-V) as well as manually independent (MACS levels I-II) or manually dependent functional levels (MACS levels III-V) ( P < .001).

Limitations: Our convenience cross-sectional sample included school-age children with primarily Caucasian, middle-income parents and may not be representative of other cultural, socioeconomic backgrounds. Not all participants had a MACS level assigned, however, no differences were found in PEDI-CAT scores between those with and without MACS scores.

Conclusions: These results demonstrate that the PEDI-CAT is a valid outcome instrument for measuring functional abilities in children with CP, able to differentiate across fine and gross motor functional levels.