A prospective study of laboratory and clinical measures of postural stability to predict community-dwelling fallers

Background. The identification of specific risk factors for falls in commun ity-dwelling elderly persons is required to detect early changes and permit a preventative approach to management. This study determines the ability o f various laboratory measures and clinical tests of postural stability to p rospectively predict fallers in community-dwelling elderly women. Methods. One hundred elderly women (65-86 years, mean age 73 +/- 5 years) p erformed a reaction-time step task, a limits: of stability, and a quiet sta nce balance task. Postural muscle timing and movement speed were recorded d uring the step task. Center of pressure (COP) motion was recorded in quiet stance and at the limits of stability. Four common clinical balance tests w ere performed, and balance confidence, medical and activity history questio nnaires were completed. subjects were followed up regularly for a 6-month p eriod following testing to determine the frequency and characteristics of a ny falls that occurred. predictive capabilities of the balance measures to determine fallers were determined through logistic regression models. Results. The clinical balance tests investigated were not able to predict f allers in this community-dwelling elderly population, ii combination of var iables from the laboratory tasks: provided the best overall prediction rate (77%) of fallers (sensitivity 51%) and nonfallers (specificity 91%) from l aboratory measures. Of these, step movement time and gluteus medius onset t imes were the factors best able to predict fallers. Alone. measures of COP motion in quiet stance and at the limits of stability had a pr,or ability t o predict fallers, although they could correctly identify most nonfallers. Prediction was not significantly improved when clinical balance test result s were aided to the most predictive laboratory measures. Conclusions. Not all older adults with a reduction in balance ability repor ted a fall over a 6-month period. Of those who did. a combination of measur es reflective of different aspects of mediolateral postural stability durin g a rapid step task, quiet stance, and movement to the limits of stability were best able to predict faller status, with nonfallers better predicted t han fallers. These results emphasize the importance of the multifactorial n ature of falls in the community-dwelling elderly population in that the cli nical and laboratory measures did not predict a high proportion of fallers.