The Falls Efficacy Scale International is a valid measure to assess the concern about falling and its changes induced by treatments

Abstract

Objective To test with the Rasch analysis the psychometric properties of the Falls Efficacy Scale International, a questionnaire for measuring concern about falling. Design Longitudinal observational study, before–after rehabilitation. Setting Inpatient rehabilitation. Subjects A total of 251 neurological patients with balance impairment. Interventions Physiotherapy and occupational therapy aimed at reducing the risk of falling. Main measures Participants (median age, first–third quartile: 74.0, 65.5–80.5 years; stroke and polyneuropathy: 43% and 21% of the sample, respectively) received a balance assessment (Falls Efficacy Scale International included) pre- and post-rehabilitation. Rasch analysis was used to evaluate the Falls Efficacy Scale International. Differential item functioning, which assesses the measures’ stability in different conditions (e.g. before vs. after treatment) and in different groups of individuals, was tested for several variables. Results Patients suffered a moderate balance impairment (Mini-BESTest median score; first–third quartile: 15; 11–19), mild–moderate concern about falling (Falls Efficacy Scale International: 28; 21–37) and motor disability (Functional Independence Measure, motor domain: 70.0; 57.0–76.5). Falls Efficacy Scale International items fitted the Rasch model (range of infit and outfit mean square statistics: 0.8–1.32 and 0.71–1.45, respectively) and the questionnaire's reliability was satisfactory (0.87). No differential item functioning was found for treatment, gender, age and balance impairment. Differential item functioning was found for diagnosis and disability severity, but it is shown that it is not such as to bias measures. Conclusions Falls Efficacy Scale International ordinal scores can be turned into interval measures, i.e. measures of the type of temperature. Being differential item functioning-free for treatment, these measures can be safely used to compare concern about falling before and after rehabilitation, such as when interested in assessing the rehabilitation effectiveness.