Three-dimensional kinematics of the upper limb during a Reach and Grasp Cycle for children

The ability to reach, grasp, transport, and release objects is essential for activities of daily living. The objective of this study was to develop a quantitative method to assess upper limb motor deficits in children with cerebral palsy (CP) using three-dimensional motion analysis. We report kinematic data from 25 typically developing (TD) children (11 males, 14 females; ages 5-18 years) and 2 children with spastic hemiplegic CP (2 females, ages 14 and 15 years) during the Reach and Grasp Cycle. The Cycle includes six sequential tasks: reach, grasp cylinder, transport to mouth (T(1)), transport back to table (T(2)), release cylinder, and return to initial position. It was designed to represent a functional activity that was challenging yet feasible for children with CP. For example, maximum elbow extension was 43+/-11 degrees flexion in the TD group. Consistent kinematic patterns emerged for the trunk and upper limb: coefficients of variation at point of task achievement for reach, T(1), and T(2) for trunk flexion-extension were (.11, .11, .11), trunk axial rotation (.06, .06, .06), shoulder elevation (.13, .11, .13), elbow flexion-extension (.25, .06, .23), forearm pronation-supination (.08, .10, .11), and wrist flexion-extension (.25, .21, .22). The children with CP demonstrated reduced elbow extension, increased wrist flexion and trunk motion, with an increased tendency to actively externally rotate the shoulder and supinate the forearm during T(1) compared to the TD children. The consistent normative data and clinically significant differences in joint motion between the CP and TD children suggest the Reach and Grasp Cycle is a repeatable protocol for objective clinical evaluation of functional upper limb motor performance.