A COMPARISON OF PREHENSION FORCE CONTROL IN YOUNG AND ELDERLY INDIVIDUALS

Age-related changes were investigated in the control of precision grip force during the lifting and holding of objects with slippery (silk) and nonslippery (sandpaper) surface textures. Two groups of active eld erly adults comprising individuals aged 69-79 years (n = 10), and 80-9 3 years (n = 10) together with a group of young adults aged 18-32 year s (n = 10) participated in the study, Each subject lifted a free weigh t (3N) during which time gripping and lifting forces mere monitored, T he elderly subjects, especially the individuals in the 81-93 year grou p, had a larger number of fluctuations In the grip force rate curve an d longer force application time than the younger subjects during lifti ng, The effect of prior experience with one surface on the following d ifferent surface was more pronounced in the younger subjects than the elderly subjects. These results suggest a decline in programmed force production capacity with increased age, The fingers of the elderly sub jects were more slippery and they exhibited a greater safety margin of the grip force while hording the object than the younger adults, The overall results demonstrated chat precision grip force control capacit y declines with advancing age. It is suggested that this decline is du e mainly to age-related changes in skin properties, and cutaneous sens ibility functions, and in part to central nervous system function.