2.1  CONCEPT OF BALANCE CONTROL ANALYSIS

The SwayStar™ program records and analyses a test person’s balance control capabilities for a set of several stance and gait tasks. For this purpose trunk-sway measurements are used. SwayStar™ answers the need for a simple series of tests from which calculations are derived to indicate the degree or absence of a balance and/or gait disorder. It takes into consideration the fact that individuals with balance instabilities tend to fall in a variety of directions that include both roll (side-to-side) and pitch (front-to-back) directions. Although separate tests exist for both stance and gait analysis, these have no single battery of tests and measurements like those of SwayStar™ which cover the entire range of stance and gait responses. SwayStar™ focuses on those trunk-sway measures that are most sensitive for indicating a balance or gait disorder, and performs these measures simply and rapidly.

Tasks that involve reducing or disturbing sensory inputs (eye closure or standing on a foam support surface) produce larger sway magnitudes than when standing eyes open or on a normal surface. Removing visual input increases sway, as does using a foam surface on which to stand or walk. The SwayStar™ test battery includes evaluation procedures like those of computerized posturography in order to document how visual and somatosensory inputs are used in these environments.

The SwayStar™ summary reports indicate for a set of clinical stance and gait tests whether there is a need for further evaluations that require the use of more elaborate equipment and different expertise. It does this based on quantitative measurements. Thus, SwayStar™ is both cost and time effective. Individuals with balance deficits show instability either during stance and gait tasks or both, particularly following acute onset of a deficit. Repeating the SwayStar™ tests after a treatment regime will permit the clinician to quantify any improvement in the patients’ stance and gait instability. Although the sway demonstrated by such subjects is often mainly side to side (roll plane), falling in the direction of the deficit, instability in other directions such as the front-to-back (pitch plane) also occurs. SwayStar™ is the only system that includes both measurement possibilities in a single test battery using a single device.