The Validity, Responsiveness, and Interpretability of the Activities-specific Balance Confidence Scale in Patients with Subacute Stroke: A Preliminary Investigation

BackgroundThe Activities-specific Balance Confidence (ABC) scale lacks sufficient psychometric evidence for use in patients with subacute stroke.ObjectiveTo investigate the floor and ceiling effects, construct validity, responsiveness, and the minimal important change (MIC) of the ABC scale in patients with subacute stroke.MethodsThe cases of patients with subacute stroke (n = 62) were analyzed for floor/ceiling effects and construct validity at baseline; those of 39 of the patients were analyzed for responsiveness and MIC at baseline and after 4 weeks. Outcome measures included the ABC scale, Mini-Balance Evaluation Systems Test (Mini-BESTest), Timed Up and Go test (TUG), comfortable walking speed (CWS), and maximal walking speed (MWS) measured at both baseline and 4-week follow-up. The MIC was calculated using a ≥ 4-point improvement on the Mini-BESTest as the anchor.ResultsThe ABC scale's total score did not exhibit any floor or ceiling effects. The ABC scale was correlated with the Mini-BESTest (ρ = 0.74), TUG (ρ = -0.56), CWS (ρ = 0.60), and MWS (ρ = 0.64). The correlation of change score between the ABC scale and Mini-BESTest was ρ = 0.39. The MIC for the ABC scale was 15.6% (95%CI: 10.4%-21.1%).ConclusionsThe ABC scale may help assess self-efficacy in patients with subacute stroke.