Discriminative, predictive, and evaluative properties of a trunk control measure in patients with stroke

Background and Purpose. The trunk control items of the Postural Assessment Scale for Stroke Patients (PASS-TC) have been proposed for use in examining patients with stroke. The purpose of this study was to examine the discriminative and predictive validities and the evaluative properties of the PASS-TC at 14, 30, 90, and 180 days after stroke onset. Subjects and Methods. A total of 269 patients with stroke participated in this prospective study. The PASS-TC was administered at the 4 time points after stroke onset. The distributions of the PASS-TC scores were used to determine the discriminative ability to distinguish between individuals at the 4 time points. A comprehensive activities of daily living (CADL) measure was administered 1 year after stroke onset as an external criterion for examining the predictive ability of the PASS-TC. Changes in PASS-TC scores between the intervals of 14 to 30, 30 to 90, and 90 to 180 days after stroke onset were used to examine the evaluative properties of the measure. Results. The PASS-TC scores exhibited differences between the patients with disability and the patients without disability at the 4 time points. The scale, however, showed a notable ceiling effect at the 4 time points (>30% of the subjects), indicating a limited discriminative ability between individuals. The scores of the PASS-TC at the 4 time points were moderately correlated with the CADL scores at 1 year after stroke onset (Spearman ρ≥.5), evidence of its predictive validity. The responsiveness of the PASS-TC was moderate at 14 to 30 days after stroke (standardized response mean [SRM] = .65) and limited at 30 to 90 and 90 to 180 days after stroke (SRM=.42 and .02, respectively). Discussion and Conclusion. The results provide evidence that the PASS-TC can predict CADL function at 1 year after a stroke, but the discriminative and evaluative abilities are limited over the first 6 months after a stroke. To promote the utility of the PASS-TC in stroke research, it will be necessary to reduce its ceiling effect and improve its evaluative ability.