Validation of Yonsei-Bilateral Activity Test (Y-BAT)-Bilateral Upper Extremity Inventory Using Rasch Analysis.

There is little assessment to provide specific information about quality of bilateral upper extremity movement specifically. This study examined the psychometric properties of the Yonsei-Bilateral Activity Test (Y-BAT). An observational cross-sectional design was used with 100 stroke survivors. Unidimensionality was examined using factor analyses, and Rasch analysis was used to test rating scale structure, fit statistics, and precision of the Y-BAT. The Y-BAT demonstrated a unidimensional measurement construct, and 19 of the 27 items fit the Rasch model. The instrument demonstrated good precision, including person reliability and person strata. The Y-BAT estimated person measures within a wide range of theta values with a reliability of .9 with good precision. Our results indicate that a revised, 19-item version of the Y-BAT demonstrates sound internal validity and may be a useful instrument for clinicians to measure upper extremity function with good precision following stroke.