Deep Brain Stimulation and Movement Disorder Treatment

Abstract

Deep brain stimulation (DBS) for movement disorders involves the targeted application of electrical current to specific brain regions in order to improve motor function. Despite early work on DBS in the middle of the twentieth century, it did not become a widely available and accepted therapy for movement disorders until the 1990s. DBS is applied within the cortex–basal ganglia–thalamus–cortex circuit to alter the dysfunctional neuronal activity characteristic of movement disorders. The exact mechanism of action of DBS is not entirely clear. Depending on its location and position relative to neuronal cell bodies and axons, DBS may alter neurophysiological properties and block or facilitate neurotransmitter release, leading to increased or decreased downstream activation. The principal movement disorders treated with DBS are Parkinson’s disease, dystonia, and essential tremor. The main movement disorder targets for DBS are the subthalamic nucleus, the internal segment of the globus pallidus, and the ventral intermediate nucleus of the thalamus. DBS surgery involves the precise identification and localization of the desired target and then the insertion and implantation of the DBS electrode and internal pulse generator. The placement of the DBS electrode is guided by brain imaging, neuronavigational software, and intraoperative electrophysiological mapping. The major advantages of DBS over surgical lesioning procedures are its adjustability and reversibility. DBS is associated with significant improvements in motor function, activities of daily living, and quality of life for patients with movement disorders.