Rasch Analysis of the Arabic Language Version of the Functional Disability Inventory

It is important for the responsive and effective treatment of pediatric cancer patients that functional disability is successfully measured, but no measures of functional disability have been validated for use with Arabic-speaking children and adolescents. The purpose of this study was to examine the psychometric characteristics of the first Arabic translation of the Functional Disability Inventory (FDI). A methodological study limited to the secondary analysis of functional disability data on 62 pediatric patients in Lebanon using the rating scale model and WINSTEPS Rasch analysis software was used. Disordered responses to 4 FDI times suggest that the Arabic translation of the rating scale categories might need revision or supplementation with a visual analogue scale. The dimensionality of the FDI needs further exploration because principal component analyses of residuals suggested the presence of secondary and possibly higher order dimensions. Additional FDI items are needed to improve targeting if low levels of functional disability are demonstrated to be clinically important for patient assessment and pain management. The FDI-A is suitable for clinical assessment and for monitoring the outcomes of pain management in Lebanese pediatric cancer patients. Our findings support the construct validity of the FDI-A and acceptable reliability for the 15-item scale, Cronbach α .93 and .85 for 4 of the item subsets we examined. Rating scale categories and the dimensionality of the FDI-A require further examination. The clinical relevance of distinctions between levels of functional disability in children and adolescents with cancer pain remains to be established.