A debate remains over the optimal target (Subthalamic Nucleus STN or Globus Pallidus Internus GPi). The CNS guidelines reviews Class I evidence to address specific questions regarding target selection. Both STN and GPi stimulation provide similar improvements in motor function in the “on” medication/ “on” stimulation state. Both are effective in reducing dyskinesias and improving quality of life. Risk of adverse events is similar between targets. STN and GPI DBS result in differential effects on some outcomes. Specifically, STN is superior to GPi in reduction of dopaminergic medications. GPi DBS is associated with a lower risk of cognitive decline and of mood disturbance. There remains conflicting data as to whether STN is superior to GPi in motor response in the “off” medication/ “on” stimulation state. Additionally, GPi may be superior in reducing “on” medication dyskinesias, though the reduction of “on” time without bothersome dyskinesias appears to be similar.
In summary, STN and GPi DBS are equally effective in the treatment of motor symptoms of PD. Concerns regarding the risks of cognitive decline, mood disturbance, and desire to reduce dopaminergic medications should be considered when choosing the optimal target.