Spectral characteristics of postural control in elderly individuals.

OBJECTIVE To examine the feasibility of using spectral analysis techniques to identify potential biomarkers of diminished postural control in elderly individuals. DESIGN Data from spectral signatures (derived from postural sway) of 21 young adults and 42 elderly individuals classified as "high" or "low" risk with regard to functional balance capacity were analyzed using Risk Category (3) x Sensory Condition (3) multivariate analyses of variance. Postural control was challenged by varying the visual conditions under which individuals stood on a measurement platform. RESULTS Results indicated that measures of central tendency and dispersion of the spectral frequency distribution from medial-lateral components of sway (but not antero-posterior sway) clearly differentiated between "high" and "low" risk elderly. Low risk elderly were not different from young adults. High risk elderly exhibited greater dispersion and lower mean frequency than other groups. CONCLUSIONS Differences in spectral characteristics of medial-lateral components of sway were more related to risk category than to age. Elderly persons with high functional balance capacity displayed characteristics similar to those of young adults. Thus, spectral frequency analysis techniques may be a clinically useful tool for identifying individuals potentially at risk of falling.

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