Stabilizing and destabilizing effects of vision and foot position on body sway of healthy young subjects: a posturographic study.

A total of 800 posturographic measurements--each characterized by four values (sway path, sway area, anteroposterior sway and lateral sway)--was carried out for this study. Eight different conditions (interfoot distances of 0, 4, 10 and 20 cm, each with eyes open and eyes closed) were compared by statistical means. All sway values were diminished by vision in small interfoot distances. At large interfoot distances, however, the presence of visual control resulted in an increase of lateral sway. Comparing the different foot positions, an increase of anteroposterior sway and a decrease of all other components were found at large interfoot distances no matter whether the eyes were open or closed.