Balance performance on the postural stress test: comparison of young adults, healthy elderly, and fallers.

The purpose of this study was to compare the postural responses of three groups of individuals--healthy young adults (n = 42; age, 20-40 years); healthy, community-dwelling, elderly individuals (n = 66; age, 60-102 years), and elderly individuals with a history of frequent falls (n = 10; age, 66-95 years)--using the postural stress test (PST). The PST is a simple, clinically applicable, quantitative measure of an individual's ability to withstand a series of graded destabilizing forces applied at the level of the subject's waist. Elderly fallers tend to score lower on the PST than elderly nonfallers, but age-related differences in postural responses during the PST have not been established. Each subject underwent the PST using a method and scoring procedure described previously. Results of this study confirm previous findings that elderly fallers score significantly lower on the PST than either young adult or nonfalling elderly individuals. This study also showed that there was no difference in balance strategy scores between the young adults and the healthy elderly subjects. Therefore, it appears that poor performance on the PST cannot be attributed to age alone, but may be predictive of pathological processes that predispose an individual to frequent falls.