Hemiballismus: current concepts and review

Hemiballism is a rare movement disorder characterized by a high amplitude movement of an entire limb or limbs on one side of the body. The acute development of hemiballismus is often caused by focal lesions in the contralateral basal ganglia and STN. Many etiologies exist for this rare disorder with vascular causes and nonketotic hyperglycemia being the most common. Clearer understanding of the pathophysiology of hemiballism has led to important insights into the function and interaction of structures within the basal ganglia. Newer models of basal ganglia function have been proposed based on the study of the pathophysiology of hemiballism. Prognosis is favorable for most patients with complete resolution with or without treatment. Medical and surgical treatments are often successful in reducing or completely ameliorating the movements in those patients with more severe movements.