Mirror versus stationary cross feedback in controlling the center of foot pressure displacement in quiet standing in elderly subjects.

OBJECTIVE To investigate the effect of mirror feedback on postural control during quiet standing in elderly adults. DESIGN Before and after intervention trials. SETTING Pneumology center in France. PARTICIPANTS Eleven elderly adults (mean age, 70.7+/-4.6 y; mean body weight, 64.5+/-15.0 kg; mean height, 161.4+/-12.0 cm). INTERVENTIONS Participants were asked to stand upright, as immobile as possible, in 2 eyes-open and mirror-feedback conditions. The latter experimental condition consisted of supplying the subjects with their frontal reflection by positioning a mirror in front of them. MAIN OUTCOME MEASURES Foot center of pressure (COP) displacements in the mediolateral (ML) and anteroposterior (AP) directions were recorded using a force platform. RESULTS The mirror-feedback condition had different effects on postural sway, depending on the direction: range, variability, and maximal instantaneous speed of the COP displacements decreased in the ML direction, whereas these effects remained unchanged in the AP direction. CONCLUSIONS This study provided evidence that mirror feedback may put elderly adults at lower risk of falling.