Comparison of clinical and biomechanical measures of balance and mobility in elderly nursing home residents.

Objective: To compare biomechanics force platform measurements of postural sway with clinical measures of balance and mobility, in frail elderly residents of community nursing homes, in terms of feasibility, correlation with other known risk factors for falls, and intercorrelation with each other.

Design: Cross-sectional study.

Setting: Twelve Tennessee community nursing homes.

Subjects: Of 1315 residents 360 (> or = 65) could stand independently (> or = 10 seconds). Of these eligible subjects, 303 (84%) provided informed consent and were assessed.

Measurements: The biomechanics force platform measurements were postural sway during quiet standing characterized as elliptical area and mean velocity. The clinical measures were functional reach, mobility maneuvers (adapted from Tinetti's Mobility Index), timed chair stands, and 10-foot walk. Resident characteristics and function were also obtained.

Results: Balance measurements were obtained on most (100% for postural sway to 67% for chair stand) consenting residents and were reliable on test-retest (intraclass correlation from .56 to .98). Performance in both groups of balance measures deteriorated with increasing musculoskeletal disability. Functional reach and mobility maneuvers correlated with height, and mobility maneuvers with depressive symptoms. Elliptical area correlated with mean velocity of postural sway (Pearson's r = 0.72; P < 0.001), and the clinical measures of balance (functional reach, mobility maneuvers, timed chair stands and walk) were modestly intercorrelated (r from 0.35 to 0.65; all P values < or = 0.05). However, the biomechanical measures were not correlated with the clinical measures.

Conclusions: Standard measures of balance were obtained reliably from nursing home residents who could stand independently for > or = 10 seconds. However, in this group, further research is needed to determine which measures best predict falls. Further research is also needed to identify predictors of falls in the majority of residents who were too frail to undergo these standard assessments.