Responsiveness of the Falls Efficacy Scale-International and Activities-Specific Balance Confidence Scale in Parkinson's disease.

Abstract

This study aimed to establish the minimal clinically important difference (MCID), minimal detectable change (MDC), and substantial clinical benefit (SCB) values for the Falls Efficacy Scale-International (FES-I) and the Activities-specific Balance Confidence (ABC) scales in people with Parkinson's disease (PwPD). A total of 119 PwPD completed an intervention program. Fear of falling and balance confidence were assessed before and after the intervention using the FES-I and ABC scale, along with the Global Rating of Change (GRoC). Anchor-based analyses identified MCIDs of -5.7 points for FES-I and 9.6% for the ABC scale. SCBs were determined as -17.4 points for FES-I and 24.7% for the ABC scale using the mean-difference method. Receiver operating characteristic (ROC) analyses yielded optimal MCID cutoffs of ≥ -2 for FES-I and ≥ +5% for ABC scale, and SCB cutoffs of ≥ -10 for FES-I and ≥ +7.5% for ABC scale, all with high sensitivity and specificity. Distribution-based MDC estimates ranged from 2.7-7.4 points for FES-I and 4.7-13.1% for the ABC scale. This study provides robust MCID, MDC, and SCB estimates for FES-I and ABC scale in PwPD, offering clinically meaningful benchmarks to guide interpretation of change and evaluate the effectiveness of balance and fear-of-falling interventions.