REACH TO GRASP - CHANGES WITH AGE

This study provides the first known kinematic assessment of the reach- to-grasp movement in elderly subjects. Twelve subjects (aged 60-71) we re compared to gender-matched younger subjects (aged 18-25). Subjects reached 35 cm to grasp either a small (0. 7 cm) or a large (8 cm) diam eter cylinder. Precision grip was naturally adopted for the small cyli nder, and whole hand prehension for the large cylinder. The displaceme nts of active infrared markers (wrist and hand) were recorded with an Optotrak system. Movement initiation time, movement duration, and kine matic parameters of the reach-and-grasp components were computed. Olde r subjects showed slower, longer movements with a prolonged approach p hase. However, the patterning and coordination of this movement, with respect to the utilization of a precision grip or whole hand prehensio n, were similar for both groups. Subtle changes with age thus appear t o reflect a strategy that develops to compensate for deterioration in other systems such as visual or proprioceptive.