Examining the characteristics of balance dysfunction in patients with stroke using Item response theory

Balance dysfunction in patients with stroke involves specific postural control systems. Identifying which balance functions are most prone to impairment in patients with stroke may guide interventions to enhance safety, activities of daily living, and ambulation. To characterize balance dysfunction in patients with stroke by comparing them with community-dwelling older adults and patients with musculoskeletal disorders using the Brief-BESTest and Item Response Theory (IRT). We enrolled 75 inpatients with stroke, 75 community-dwelling older adults, and 71 inpatients with musculoskeletal disorders. Before applying the graded response model, we confirmed the Brief-BESTest’s unidimensionality, local dependence, and monotonicity. We then evaluated item difficulty using β parameters across and within groups. Total scores did not differ among the three groups. Patients with stroke scored significantly lower than both comparison groups on Item 2 (functional reach forward) and Item 7 (stance with eyes closed on foam). Hierarchical ordering based on β values suggested that Item 7 was the most challenging task for patients with stroke. IRT analysis suggested that Item 7 (standing with eyes closed on foam) is a particularly challenging and stroke-specific task. IRT complemented classical test theory by revealing the potential stroke-specific characteristics of balance dysfunction.