Reach to grasp: changes with age

Abstract

This study provides the first known kinematic assessment of the reach-to-grasp movement in elderly subjects. Twelve subjects (aged 60-71) were 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) diameter cylinder. Precision grip was naturally adopted for the small cylinder, and whole hand prehension for the large cylinder. The displacements of active infrared markers (wrist and hand) were recorded with an Optotrak system. Movement initiation time, movement duration, and kinematic parameters of the reach-and-grasp components were computed. Older subjects showed slower, longer movements with a prolonged approach phase. However, the patterning and coordination of this movement, with respect to the utilization of a precision grip or whole hand prehension, were similar for both groups. Subtle changes with age thus appear to reflect a strategy that develops to compensate for deterioration in other systems such as visual or proprioceptive.