Psychometric Properties of 2 Simplified 3-Level Balance Scales Used for Patients with Stroke

Abstract

BACKGROUND AND PURPOSE: To determine if the 3-level scales yield data as reliable and valid as data obtained for the original scales, 2 simplified 3-level measures of balance--a modified Berg Balance Scale (BBS-3P) and a modified Postural Assessment Scale for Stroke Patients (PASS-3P)--were proposed by the researchers, and psychometric properties of each were compared with those of the original measures (the Berg Balance Scale [BBS] and the Postural Assessment Scale for Stroke Patients [PASS], respectively) in patients with stroke. SUBJECTS AND METHODS: The study consisted of 2 parts. The first part examined the reliability and concurrent and convergent validity of measurements obtained with these instruments. A total of 77 patients participated in this part of the study. The 3 levels in the center of the BBS were collapsed to a single level (ie, 0-2-4) to form the BBS-3P. Similarly, the 2 middle scores of the center of the PASS were averaged (ie, 0-1.5-3) to form the PASS-3P. In the second part of the study, the predictive validity and responsiveness of these measures were examined. The BBS and PASS scores of 226 patients were retrieved from the records of participants in the Quality of Life After Stroke Study, and these scores were converted into the proposed BBS-3P and PASS-3P scores. RESULTS: The BBS-3P and PASS-3P showed high concurrent validity with the BBS and PASS, good predictive validity for disability, and moderate to high responsiveness. Importantly, the psychometric properties of the BBS-3P and PASS-3P were essentially identical to those of the original BBS and PASS. DISCUSSION AND CONCLUSION: The psychometric properties of both simplified 3-level balance measures were comparable to those of the full, nontruncated scales. Future study is needed to investigate how much meaningful utility can be gained from the scheme of simplification of scaling.