It is known that impaired balance is associated with falls in older adults; however, there is no accepted gold standard on how balance should be measured. Few studies have examined measures of postural sway and clinical balance concurrently in large samples of community-dwelling older adults. We examined the associations among 4 types of measures of laboratory- and clinic-based balance in a large population-based cohort of older adults.
We evaluated balance measures in the Maintenance of Balance, Independent Living, Intellect and Zest in the Elderly Boston Study (276 men and 489 women ages 64-97 years). The measures included laboratory-based anteroposterior (AP) path length and mean sway speed, mediolateral (ML) mean sway and root mean square, and area of ellipse postural sway; the Short Physical Performance Battery (SPPB); the Berg Balance Scale; and the one-leg stand test. Spearman's rank correlation coefficients were assessed among the balance measures.
The area of ellipse sway was highly correlated with the ML sway measures (r = >0.91, P < 0.0001) and sway speed was highly correlated with AP sway (r = 0.97, P < 0.0001). The Berg Balance Scale was highly correlated with the SPPB (r = 0.74, P < 0.001) and the one-leg stand test (r = 0.82, P < 0.001). Correlations between the laboratory- and clinic-based balance measures were low but statistically significant (-0.29 ≤ r ≤ -0.16, P < 0.0001).
Clinic-based balance measures, and laboratory-based measures comparing area of ellipse with ML sways or sway speed with AP sway, are highly correlated. There is less correlation between the clinic- and laboratory-based measures. Since both laboratory- and clinic-based measures inform balance in older adults, but are not highly correlated with each other, future work should investigate the differences.