A Multidisciplinary Cross-Cultural Measurement of Functioning After Stroke: Rasch Analysis of the Brief ICF Core Set for Stroke

Abstract

Purpose: To investigate the possibility of constructing a multiprofessional cross-cultural measure of functioning after stroke across categories of the International Classification of Functioning, Disability and Health (ICF). Method: Data on 757 stroke survivors from China, Germany, Italy, and Sweden, including ratings of 15 categories from the Brief ICF Core Set for stroke, were analyzed using the Rasch model. Unidimensionality, reliability, fit of the ICF categories to the model, ordering of response options of the ICF qualifier, and presence of differential item functioning (DIF) were studied. Results: Of the 15 ICF categories, response options for 7 categories were collapsed, 5 categories were deleted due to misfit, and 4 ICF categories showed DIF for country and were accordingly split into country-specific categories. The proposed final clinical measure consists of 20 ICF categories (6 categories were country-common) with an overall fit statistic of χ²₁₈₀ = 184.87, P = .386, and a person separation index of r = 0.72, which indicates good reliability. Based on an individual’s functioning after stroke, the ratings across the different ICF categories can be summed on an interval scale ranging from 0 to 100. Conclusion: A construction of a cross-cultural clinical measure after stroke based on ICF categories across body functions, structures, and activities and participation was possible. With this kind of clinical measure, stroke survivors’ functional levels can be compared even across countries. Despite the promising results, further studies are necessary to develop definitive measures based on ICF categories.

Keywords:

• disability
• ICF
• outcome measures
• Rasch analysis
• stroke