A Psychometric Investigation of Objective and Therapist-rated Performance Measures in a Pediatric Chronic Pain Population: How Well Do These Measure Work?

Abstract

During intensive interdisciplinary pain treatment (IIPT) for pediatric chronic pain, multiple methods are used to assess pain-related function and physical impairment/improvement. Outside of the Functional Disability Inventory (FDI), few studies have examined which assessments best capture functional improvements as a result of IIPT. The aim of the current study was to investigate the psychometric properties of commonly used physical rehabilitation measures in a sample of pediatric patients with chronic pain receiving IIPT. Participants included 140 pediatric patients (M age=14.71, SD=2.39; female=74%) with primary diagnoses of musculoskeletal pain, abdominal pain, and headache. Investigation of the psychometric properties of the Functional Independence Measure for Children (WeeFIM), the Bruininks-Oseretsky Test of Motor Proficiency (BOT-2 upper and lower subtests), the Canadian Occupational Performance Measure (COMP performance and satisfaction assessment domains), 6-minute walk test, 30-second step test, and grip strength included descriptive statistics assessed at admission and discharge. The shape of the distributions was a focus with skewness and kurtosis of greater than |1| used to identify non-normal distributions. At admission, WeeFIM (-3.4), COPM-S (1.3), and BOT-2 UL (-1.8) demonstrated significant skew. At discharge, WeeFIM (-5.4), BOT-2 BL (1.7), and 6-minute walk test (-1.2) showed increased skew. Several variables showed kurtosis (1-4) including COPM-S, BOT-2 BL, BOT-2 UL at admission and BOT-2 BL, 6-minute walk test, and grip strength at discharge. The WeeFIM demonstrated significant kurtosis (admission=15.5; discharge=36.5). All measures were moderately correlated with the FDI at admission with the strongest relationships between the 6-minute walk test (-.39) and 30-second step test (-.34). The WeeFIM, seems particularly problematic for use within this population. The overwhelming majority of patients score at the top of the distribution at admission prohibiting demonstration of treatment gains. The BOT-2 and COPM performed somewhat better although caution should still be used. Recommendations for assessment in pain treatment are provided.