Time-frequency analysis of postural sway

Maintaining upright balance is a dynamic process in humans, dependent upon sensory input from the visual, vestibular (i.e., inner ear) and somatosensory systems. Deficiencies in one of these sensory systems often result in abnormal postural responses to external disturbances. Studying these responses, via measurement and analysis of postural sway, can yield insight into the nature of the system deficiency. Past efforts have utilized spectral analysis to study postural sway. However recent work has shown that the frequencies of postural sway change over time; hence, spectral analysis provides an incomplete description of the system. The authors present results from their work in time-frequency analysis of postural sway, and discuss its potential as a clinical tool for assessing balance disorders