Mechanisms for disturbed motor coordination in stroke: an analysis of voluntary movement trajectories

Analyses of hand movement planar trajectories in paretic and contralateral arms of hemiparetic stroke patients indicate that there are disturbances in all phases of limb motion, including the initial movement direction, in mid-course trajectory, and in the terminal deceleration phase associated with movement termination. Analyses of movement kinematic and kinetic characteristics and of concurrent electromyograms suggest that trajectory disturbances are mediated by several deficits. These include disruption of spatial coordinate frameworks specifying motion direction, loss of internal models of limb mechanical behavior, and in some muscles, by inappropriate stretch reflex action in antagonist muscles.