Indications for Deep Brain Stimulation Therapy in Parkinson’s Disease

Parkinson’s disease (PD) is a degenerative movement disorder that affects 7 to 10 million people worldwide. The cardinal clinical features of PD are resting tremor, muscle rigidity, bradykinesia, and postural instability. These movement abnormalities are principally caused by death of dopamine-producing neurons in the substantia nigra. Most patients in early-stage PD respond well to medical therapy, usually levodopa, which alleviates these cardinal symptoms by replacing dopamine. After years of levodopa therapy, however, many patients develop motor fluctuations and experience an increase in “off” time (periods of time where the benefits of medications are limited). Deep brain stimulation (DBS) therapy is a surgical treatment that dramatically improves motor fluctuations as well as the principal features of bradykinesia, tremor, and rigidity. Additionally, DBS can be used to treat medication-induced dyskinesias. Although DBS therapy does not slow the progression of PD, it has been proven to improve motor fluctuations and quality of life beyond what can be achieved with best medical therapy. Patient selection is critically important in order to obtain these significant benefits, and dopamine responsiveness is a key diagnostic test. Due to the heterogeneity of PD symptoms and the complexity of accurate diagnosis, a team process for patient selection should be used. In this chapter, we will review the indications and patient selection criteria for DBS therapy for Parkinson’s disease.