Treatment of Persistent Hemiballism with Deep Brain Stimulation of the Globus Pallidus Internus: Case Report and Literature Review.

Abstract

Hemiballism is a rare hyperkinetic movement disorder characterized by involuntary, high-amplitude, unilateral flailing of upper or lower extremities or both. In the case of hemiballism refractory to pharmaceutical interventions, deep brain stimulation (DBS) is an effective primary neurosurgical treatment. DBS targets for hemiballism include the thalamus, subthalamic nucleus, and globus pallidus internus (GPi). We present a case of a patient who sustained a posterior cerebral artery ischemic stroke that eventually led to uncontrolled hemiballism, which was then successfully treated by unilateral GPi stimulation. We include a video depicting the patient preoperatively, intraoperatively with stimulation off, and intraoperatively with stimulation on. We also review published cases of hemiballism treated by GPi-DBS, which support the claim that GPi-DBS is an effective method for treating hemiballism. Evidence gathered from the literature indicates that GPi-DBS is an effective treatment for hemiballism, especially after neuroleptics have failed. Results from various case studies of GPi-DBS used to treat hemiballism reveal improved motor ability and decreased dyskinesia, although degree of improvement may vary. More studies are required to establish which DBS target requires the least amount of stimulation to treat hemiballism.