Discriminative ability of Fall Efficacy Scale International in Iranian people with multiple sclerosis

BACKGROUND: The discriminative validity of fall efficacy scale international (FES-I) in differentiating between fallers and non-fallers, levels of functional mobility, dynamic balance and disability has not been assessed in Persian speaking people with multiple sclerosis (MS). OBJECTIVE: To assess reliability, factor structure, construct and known group validity, sensitivity and specificity of FES-I for differentiating individuals with and without a history of fall and determining a cutoff point of the Persian version of the FES-I in people with MS. METHOD: One hundred thirty people with all subtypes of MS were included. The ability of FES-I in differentiating fall history was assessed using receiver operating characteristic (ROC). Also the FES-I score of groups based on expanded disability status scale (EDSS) 1-3.5 low and 4-6 moderate, time up and go (TUG) >/=14 sec and functional reach test (FRT) >/=25 cm were compared. The correlation between FES-I with EDSS, TUG, FRT and short form health survey (SF-36) was assessed. RESULTS: The ROC curve analysis revealed that the FES-I could differentiate people with MS based on fall history at a cutoff score of 35.5. The area under the curve (AUC) was 0.86 (sensitivity 76%; specificity 95%). Significant difference was observed between the FES-I score of groups with moderate and low EDSS scores (d = 2.98), higher than 14 sec TUG (d = 2.18) and lower than 25 cm FRT(d = 2.53). Significant high correlation was observed between FES-I with TUG (r = 0.88), EDSS (r = 0.91), FRT (r = -0.83), SF-36 physical (r = -0.87) and mental (r = -0.70) subscales. CONCLUSIONS: The Persian versions of the FES-I could differentiate people with MS with fall history, higher disability, lower functional mobility and balance deficiency.