Mouvements anormaux et accident vasculaire cérébral [Movement disorders in stroke]

Dyskinesias are infrequent presentations in acute stroke (1%). They can be found more frequently as delayed presentations after a stroke, but the prevalence is not available from the literature. The full spectrum of hyper- and hypo-akinetic syndromes has been described, but three main pictures are rather specific of an acute stroke: limb shaking, hemichorea-hemiballism and unilateral asterixis. Besides limb shaking, that seems to reflect a transient diffuse ischemia of the frontosubcortical motor pathway, lesions are described at all levels of the frontosubcortical motor circuit including the sensorimotor frontoparietal cortex, the striatum, the pallidum, the thalamic nuclei, the subthalamic nucleus, the substantia nigra, the cerebellum, the brainstem and their interconnecting pathways, as ischemic or hemorrhagic strokes. The preferentially late development of dyskinesia could reflect the return to a more ancestral motor control level, the most functional possible with the remaining configuration of structures, elaborated by brain plasticity after stroke.