Validation and Establishment of an Interval-Level Measure of the Balance Assessment in Sitting and Standing Positions in Patients With Stroke

•The Balance Assessment in Sitting and Standing Positions has sound psychometric properties.•The Balance Assessment in Sitting and Standing Positions is as responsive as the Postural Assessment Scale for Stroke Patients.•Rasch scores of the Balance Assessment in Sitting and Standing Positions can identify patients' balance ability.

ObjectiveTo validate the psychometric properties of the Balance Assessment in Sitting and Standing Positions, including validity (unidimensionality and concurrent validity), reliability (Rasch reliability), and responsiveness (compared with the Postural Assessment Scale for Stroke Patients [PASS]) and to transform the Balance Assessment in Sitting and Standing Positions from an ordinal-level measure into an interval-level measure.DesignRetrospective cross-sectional study.SettingMedical records from a medical center.ParticipantsPatients with stroke (N=1193).InterventionsNot applicable.Main Outcome MeasuresThe 4-item Balance Assessment in Sitting and Standing Positions was used, assessing static sitting balance, dynamic sitting balance, static standing balance, and dynamic standing balance.ResultsData of 1193 patients with stroke were included for Rasch analysis. The 4 items of the Balance Assessment in Sitting and Standing Positions constituted a unidimensional construct (infit/outfit mean square, .75–1.05), had good concurrent validity (r=.70–.90), and had sufficient Rasch reliability (.93). The Balance Assessment in Sitting and Standing Positions had large responsiveness (effect size, 1.20; standardized response mean, 1.51) and was comparable with the PASS (effect size, .90; standardized response mean, 1.32).ConclusionsThe Balance Assessment in Sitting and Standing Positions has sound psychometric properties. The transformed-Rasch scores of the Balance Assessment in Sitting and Standing Positions can be used to identify patients' balance function and detect patients' changes.