Update on deep brain stimulation in Parkinson
Martinez-Ramirez D, Hu W, Bona AR, Okun MS, Wagle Shukla A. Update on deep brain stimulation in Parkinson Translational Neurodegeneration, 2015 Jun 27;4:12. doi: 10.1186/s40035-015-0034-0. eCollection 2015. PMID: 26257895 Free PMC Article
Introduction: This article is a review of recent updates regarding deep brain stimulation (DBS) in Parkinson’s disease (PD).
Parkinson’s disease is a common neurological condition with motor and nonmotor symptoms. Medicinal treatment has been available since the 60’s and has undergone significant improvements since that time. As there are side effects from the medication and the disease progresses even with the very beneficial medicinal options, surgical intervention has shown significant benefit for people with PD (PWP).
DBS Mechanism of action: It remains unclear how DBS fully works to reduce PD symptoms and the authors hypothesize that there likely are multiple contributory mechanisms of action.
Targets: Initially the ventral intermediate nucleus (VIM) was the target for DBS. After years of treatment and much research the subthalamic nucleus (STN) and globus pallidus interna (GPi) were found to show more promise. Recent randomized controlled studies have not shown significant differences between STN and GPi for motor control but there are other noted nonmotor symptoms and complications for each option depending on the study. More recently, the idea of tailoring the target for stimulation is gaining momentum as a “one size fits all” approach may not work as well as once thought and that each patient has specific symptoms that would benefit from specific targeting. Appropriate patient selection by a multidisciplinary team for DBS truly affects surgical outcome. Interestingly, the authors note that the future may show that multiple stimulation targets are needed as PD rarely affects just one area of the brain. Additional targets undergoing research include the motor cortex, substantia nigra, centromedian thalamus, zona incerta ZI, and the pedunculopontine nucleus.
Timing of DBS: Typically surgical options are years after disease onset and multiple years of medications. Newer research has shown that in a young group of PWP that underwent DBS early in their disease benefited motorically as well as regarding quality of life. There is a study currently evaluating if such benefits are also found in an older subset of PWP.
Surgical procedure: There is a lot of variability in technique for DBS. Clinical work and research will continue to evolve as there are continued improvements in technology. Careful planning prior to surgery to minimize complications and best use the technology available is important.
Adverse events: There are multiple complications that can arise during and after any neurosurgery. DBS is no different and has relatively low rates of adverse events. Specific incidence rates of specific complications are listed in the article.