Measuring physical functioning in children with spinal impairments with computerized adaptive testing

BACKGROUND: The purpose of this study was to assess the utility of measuring current physical functioning status of children with scoliosis and kyphosis by applying computerized adaptive testing (CAT) methods. Computerized adaptive testing uses a computer interface to administer the most optimal items based on previous responses, reducing the number of items needed to obtain a scoring estimate. METHODS: This was a prospective study of 77 subjects (0.6-19.8 years) who were seen by a spine surgeon during a routine clinic visit for progress spine deformity. Using a multidimensional version of the Pediatric Evaluation of Disability Inventory CAT program (PEDI-MCAT), we evaluated content range, accuracy and efficiency, known-group validity, concurrent validity with the Pediatric Outcomes Data Collection Instrument, and test-retest reliability in a subsample (n = 16) within a 2-week interval. RESULTS: We found the PEDI-MCAT to have sufficient item coverage in both self-care and mobility content for this sample, although most patients tended to score at the higher ends of both scales. Both the accuracy of PEDI-MCAT scores as compared with a fixed format of the PEDI (r = 0.98 for both mobility and self-care) and test-retest reliability were very high [self-care: intraclass correlation (3,1) = 0.98, mobility: intraclass correlation (3,1) = 0.99]. The PEDI-MCAT took an average of 2.9 minutes for the parents to complete. The PEDI-MCAT detected expected differences between patient groups, and scores on the PEDI-MCAT correlated in expected directions with scores from the Pediatric Outcomes Data Collection Instrument domains. CONCLUSIONS: Use of the PEDI-MCAT to assess the physical functioning status, as perceived by parents of children with complex spinal impairments, seems to be feasible and achieves accurate and efficient estimates of self-care and mobility function. Additional item development will be needed at the higher functioning end of the scale to avoid ceiling effects for older children. LEVEL OF EVIDENCE: This is a level II prospective study designed to establish the utility of computer adaptive testing as an evaluation method in a busy pediatric spine practice.