抄録
To investigate the visual influence on postural control in the elderly, standing pressure distribution was analyzed using a photoelastic method in 38 subjects from 19 to 78 years of age. Body sway movement was also analyzed using a force-platform analysis device in 80 subjects from 2 to 69 years of age. The photoelastic method was comprised of a 450mm × 450mm sized standing platform, an imaging system, and a loading device. Contact pressure on the loading device was visualized as a sharply defined circular ring. When their eyes were closed, the position of the center of contact pressure distribution (CCP) between their feet and the floor surface was shifted significantly backwards in people in their 70's, whereas it was shifted forwards in those aged less than 60 years. Body sway velocity became most stable in subjects in their 40's, with their eyes closed, whereas it increased rapidly and became unstable in elderly people in their 70's with their eyes closed. These results suggest that standing posture is controlled by the central nervous system in human, which matures in the 40's and becomes unstable in people aged 70 years and over. Thus, central postural aging and osteoporosis could explain why elderly people tend to fall often and fracture bones. Therefore, sufficient light at night or cataract surgery, which improves visual input for elderly people, is necessary to prevent accidents related to fall and bone fractures.
