Cross-cultural adaptation, and validity of the Italian version of the upper limb functional index (ULFI-I)

Background: Outcome measures are the scientific basis for assessment and comparison of the effects of rehabilitative interventions. Among the instruments proposed for the evaluation of musculoskeletal disorders of the upper limb, the Upper Limb Functional Index (ULFI) was recently validated and translated into several languages, but it does not yet exist an Italian version yet. Objective: To obtain an Italian validated version of ULFI, called ULFI-I. Materials & Methods: The translation process was conducted following the international guidelines of the forward/backward translation. The ULFI-I was subsequently validated by calculating: I) internal consistency (Cronbach's α and item-to-total correlation), 2) criterion validity (correlation r with the Disabilities of the Arm, Shoulder and Hand Questionnaire, DASH), and 3) test-retest reliability (ICC2,1) and measurement error (Standard Error of measurement, SEM and Minimal Detectable Change, MDC90). For the first two points we used a sample of 57 patients with upper limb orthopedic conditions, while the analysis of the reliability required a further administration of the questionnaire carried out 3 days before on 33 subjects. I. Statistical analysis showed good levels of internal consistency (Cronbach's α=.90, item-to-total correlation between .45 and .73), high criterion validity (r=.81, p<0.01) and excellent reliability test-retest reliability (ICC2,1=.94, CI=.89-.97). The SEM was found to be equal to 5 points, with a MDC90 estimated at 12 points. Conclusion: In this study the ULFI-I showed good psychometric properties, combined with speed and ease of administration and scoring. Its use will facilitate the comparison of data collected in Italy with international studies, ensuring greater uniformity of assessment.