Kinematic characteristics of arm and trunk when drinking from a glass in children with and without cerebral palsy

Background. Children with cerebral palsy (CP) often have difficulty with activities that require the upper extremities secondary to deficits in strength and range of motion, spasticity, and poor timing and coordination of movement. This study aimed to identify and compare timing and coordination of the trunk and upper extremity in children with and without CP during a functional task. Methods: Eighteen children, N = 9 with CP and N = 9 with typical development were enrolled. Participants were seated in a standard chair and instructed to drink from a glass placed at a distance of 75% of available arm length. The task was divided into 3 Phases: 1) reaching to the glass, 2) transporting the glass to the mouth, and 3) returning the glass to the table. The spatiotemporal and angular variables were analyzed with 3D kinematics of movement using a 4-camera Qualysis Motion System. Findings: Children with CP demonstrated poor upper extremity timing and coordination. Despite significant trunk displacement used as a compensation in Phase 1, children with CP demonstrated a significantly lower mean velocity and velocity peak during Phases 2 and 3; and demonstrated less straight motion which required more time and movement units in all phases. Interpretation: Children with CP demonstrated poor upper extremity timing and coordination when drinking (even when they successfully completed the task) measured by more trunk displacement, slower, less straight movements, and more movement units. Current rehabilitation strategies could consider training speed and use functional tasks that require different strategies across multiple phases.