The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P): subscales for one and two-handed tasks

Abstract

Purpose To develop a self-report measure of activity performance for upper limb prosthesis users that quantifies outcomes by level of amputation and prosthesis type. Materials and methods Telephone survey of 423 adults with major upper limb amputation (ULA) who used a prosthesis. Item generation, cognitive, and pilot testing were followed by field testing. Items were categorized as one- or two-handed. Factor and Rasch analyses evaluated unidimensionality, monotonicity, item fit, differential item functioning (DIF), and reliability. Test–retest reliability was evaluated with intraclass correlation coefficients (ICCs). Known group validity was assessed with ANOVAs. Results Respondents with unilateral ULA utilized prosthesis for 24% of unilateral and 38% of bilateral tasks. Those with bilateral ULA utilized prostheses for 64% of unilateral and 46% of bilateral tasks. Factor analyses identified a One-handed Task factor (CFI = 0.963, TLI = 0.950, and RMSEA = 0.064) and a Two-Handed Task factor (CFI = 0.958, TLI = 0.953, and RMSEA = 0.053). Response categories were collapsed to address monotonicity. After DIF adjustment, person reliability was 0.49 and 0.82 for One-handed and Two-handed Task scales, respectively, and ICCs were 0.88 and 0.91. Both scales differed by amputation level (p < 0.001). Conclusions The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) measure of upper limb function of prosthesis users has promising psychometric properties. Implications for rehabilitation Measurement of upper limb function in persons with amputation is challenging, given currently available measures which do not explicitly grade activity performance with a prosthesis. The Upper Extremity Functional Scale for Prosthesis Users (UEFS-P) builds upon the original Orthotics and Prosthetics User Survey (OPUS) UEFS Scale with modified instructions, a revised item set, response categories and scoring algorithm. The UEFS-P consists of two unidimensional scales, the One-handed Tasks scale and the Two-handed Tasks scale. The UEFS-P scales have clear advantages over existing self-report measures of upper limb function that ask about difficulty with performing functional activities without accounting for prosthesis use, and do not differentiate persons who use and do not use a prosthesis.