Deep Brain Stimulation in Parkinson's Disease.

Deep brain stimulation (DBS) has become an established therapeutic tool for treating patients with Parkinson's disease (PD) who have troublesome motor fluctuations and dyskinesias refractory to best medical therapy. In addition to its proven efficacy in patients with late PD, the EARLYSTIM trial not only demonstrated the efficacy of DBS in patients with early motor complications but also showed that it did not lose its therapeutic efficacy as the years passed by. However, like all other therapies for PD, DBS is not offered to patients either as a cure for this disease nor is it expected to stop the progression of the neurodegenerative process underlying PD; these important issues need to be highlighted to patients who are considering this therapy. This article aims to provide an introduction to residents or trainees starting a career in movement disorders of the technical aspects of this therapy and the evidence base for its use. For the latter objective, PUBMED was searched from 1946 to 2017 combining the search terms "deep brain stimulation" and "Parkinson's disease" looking for studies demonstrating the efficacy of this therapy in PD. Inclusion criteria included studies that involved more than 20 patients with a physician confirmed diagnosis of PD and a follow-up of greater than or equal to at least 12 months. The findings from those studies on motor symptoms, medication requirements, quality of life, and independence in activities of daily living in PD patients are summarized and presented in tabulated form in this paper at the end.