Considerations for patient and target selection in deep brain stimulation surgery for Parkinson's disease

Abstract

Deep brain stimulation (DBS) is an effective treatment for improving motor symptoms of Parkinson's disease among well-selected patients. Over the past 30 years, several anatomical regions have been targeted with DBS based on prior experience in lesional neurosurgery and characteristic changes in subcortical motor regulation in Parkinson's disease. In this chapter, we provide an overview of the patient selection process and surgical procedure for DBS. We also discuss the various surgical targets for DBS in patients with Parkinson's disease. The subthalamic nucleus and the globus pallidus interna are the most common surgical targets among patients with Parkinson's disease and have equivalent beneficial effects on motor symptoms. Most studies report 30-60% improvement in motor score evaluations after DBS among well-selected patients. After subthalamic nucleus DBS, patients are able to reduce medications by 50% on average. In patients with globus pallidus interna DBS, stimulation has an anti-dyskinetic effect, although medication doses remain similar. DBS of the subthalamic nucleus is generally avoided in patients with a history of depression or neurocognitive impairment. Thalamic DBS ameliorates tremor, but has little effect on bradykinesia or rigidity. Finally, the pedunculopontine nucleus DBS is an emerging experimental treatment for postural and gait instability in Parkinson's disease.