Abstract: ObjectiveTo determine the static equilibrium of elderly individuals over the age of 60 and the correlation to the age. Methods142 elderly subjects (60～95 years old) were divided into 7 groups: 60～65 years old group, 66～70 years old group, 71～75 years old group, 76～80 years old group, 81～85 years old group, 86～90 years group, and >90 years old group, 24 cases 18～30 years old as the control. The static equilibrium was examined by measuring the stability index （ST） and the spectrum analysis of postural sway under following 4 conditions: standing on solid surface with eyes open （NO），standing on solid surface with eyes closed （NC）， standing on pillows with eyes open （PO）， and standing on pillows with eyes closed （PC） using Tetrax Balance System. ResultsThe ST and the intensity of postural sway increased in the elderly group compared with the control group. NO: there were significant differences (P<0.01) in ST, F1, F4, F6, F8 among the 81～85 years group, 86～90 years old group, >90 years old group and the control group. NC: there were significant differences (P<0.01) in ST, F1, F4 among all the elderly groups and the control group, and in F6, F8 among the >66 years groups and the control group（P<0.05）. PO: there were significant differences (P<0.01) in ST, F4, F6 among the >66 years old groups and the control group, and in F1, F8 among the >71 years old groups and the control group（P<0.05）. PC: there were significant differences (P<0.01) in ST, F4 among all the elderly groups and the control group, in F6 among the >66 years groups and the control group, in F8 among the >76 years old groups and the control group, and in F1 among the >80 years old groups and the control group（P<0.05）. The ST distributed as NOP<0.01）. There were similar changes in the intensity of postural sway of F1, F4, F6, F8 bands. ConclusionThere is the significant decline of the static equilibrium in the subjects aged 80 or over and no significant decline of the static equilibrium in the subjects aged 60～80 whose compensation in the static balance may decrease.

Key words: elderly, static equilibrium, spectrum of postural sway, postural stability