The maximal width of the base of support (BSW): Clinical applicability and reliability of a preferred-standing test for measuring the risk of falling

Abstract

The aim of this study was to test the reliability and validity of a preferred-standing test for measuring the risk of falling. The preferred-standing position of elderly fallers and non-fallers and healthy young adults was measured. The maximal BSW was measured. The absolute and relative reliability and discriminant validity were assessed. The expanded timed get-up-and-go test (ETGUG), one-leg stance test (OS), tandem stance (TS), and falls efficacy scale international version (FES-I) were used to determine criterion validity. In total, 146 persons (102 females, 44 males; mean age 55±22 years, range 20–94) were recruited. Forty elderly community dwellers (8 fallers) and 26 young adults were tested twice to determine the test–retest reliability. The BSW showed acceptable test–retest reliability (Intraclass correlation coefficient, ICC2,1=0.77–0.83) and inter-rater reliability (ICC3,1=0.77–0.95) for all groups. The standard error of measurement (SEM) was between 0.77 and 1.87, and the smallest detectable change (SDC) was between 2.14cm and 5.19cm. The Bland–Altman plot revealed no systematic errors. There was significant difference between elderly fallers and non-fallers (F(1/75)=11.951; p=0.001. Spearman's rho coefficient values showed no correlation between the BSW and the ETGUG (−0.17, p=0.47), OLS (−0.04, p=0.65), TS (−0.11, p=0.21), and FES-I (−0.10; p=0.27). Only the BSW was a significant predictor for falling (odds ratio=0.736, p=0.007). The reliability and validity of the BSW protocol were acceptable overall. Prospective studies are warranted to evaluate the predictive value of the BSW for determining the risk of falling.