Turkish Validity and Reliability Study of the Functional Disability Inventory (FDI)

Objective: The aim of this metadological study is to investigate the culturual adaption, validity, and reliability of the Functional Disability Inventory (FDI) in Turkish children and adolescents with chronic headache. Method: This study included 210 children and adolescents with chronic pain (140 girls, 70 boys) and 101 typically developing children and adolescents (60 girls, 41 boys) aged 8 to 18. The Functional Disability Inventory (FDI), Adolescent Paediatric Pain Tool (APPT) intensity and total points, Wong-Baker Faces Scale (W-BFPS), Pediatric Quality of Life Inventory (PedsQL) child and parent forms, Children's Somatization Inventory (CSI), Stait Trait Anxiety Inventory child version (STAIC), and Children Depression Inventory (CDI) scales were used to investigate the participants. The FDI's validity was determined using a confirmatory factor analysis and similar scale validation. Internal consistency and test-retest analyses were carried out to determine the FDI's reliability. Statistical significance level was accepted as p<0,05. Results: The Turkish version of the FDI has strong internal consistency (Cronbach's α = 0.91) and test-retest reliability (ICC = 0.97). The confirmatory factor analysis revealed the FDI's two-factor structure. FDI showed significant correlations in direction of weak to moderate and negative-positive way between APPT intensity (r=0,624, p=0,01) and total points (r=0,643, p=0,01), W-BFPS (r=0,658, p=0,01), PedsQL children (r= -0,481, p=0,01) and parent forms (r=-0,296, p=0,01), CSI (r=0,497, p=0,01), STAIC-1 (r=0,375,p=0,01), STAIC-2 (r=0,410, p=0,01), CDI (r=0,422, p=0,01). Conclusion: The results of the current study demonstrated that the FDI has appropriate psychometric qualities and is valid and reliable for application among children and adolescents with chronic pain.