AGE-ASSOCIATED DIFFERENCES IN SENSORIMOTOR FUNCTION AND BALANCE IN COMMUNITY-DWELLING WOMEN

Tests of visual, vestibular, sensori-motor and balance function were a dministered to 550 women, aged between 20 and 99 years at a Balance an d Gait Laboratory. All of the sensory, motor and balance system measur es showed significant age-associated differences. Multiple regression analyses revealed that the measures of lower limb sensation were the c onsistent sensori-motor factors contributing to balance under normal c onditions (standing on a firm surface with eyes open or closed). Under more challenging conditions (standing on foam with eyes open) vision, strength and reaction time played significant roles, whilst when stan ding on foam with eyes closed, vestibular function also made a signifi cant contribution. Analysis of percentage increases in sway under cond itions where visual and peripheral sensation systems were removed or d iminished, compared with sway under optimal conditions, indicated that up until age 65 there was an increased reliance on vision for balance control. Beyond this age, the contribution made by vision declined, s o that in the oldest age-groups reduced vision was less able to supple ment peripheral input, resulting in increased sway areas. Peripheral s ensation however was the most important sensory system in the maintena nce of static postural stability at all ages.