ABSTRACT
Parkinson's disease patients experience motor signs and non-motor symptoms caused by the disease. Deep brain stimulation of the Subthalamic Nucleus (STN) itself or its ventral or dorsal borders is one of the treatment options indicated to treat the refractory symptoms of this disease. However, it is still unknown which edge, when stimulated, generates more beneficial effects for these patients, which is the objective of this systematic review. To answer this question, electronic and manual searches were conducted in five databases and gray literature to identify studies that answered the question in this review. The selection of studies, data extraction, and analysis of the risk of bias of the included studies were performed. In total, seven studies were included in this systematic review. Most studies presented a minimal risk of bias, and their main methodological limitation was related to the sample inclusion criteria. Stimulation of the dorsal or ventral borders of the STN resulted in improved motor signs of Parkinson's disease, with some of the studies tending towards the choice of dorsal border stimulation for better motor effects, while the improvement in non-motor symptoms and inhibitory control was due to stimulation of the ventral border. The findings of this systematic review suggest that the improvement in the motor signs of Parkinson's disease can be brought about by stimulating the dorsal or ventral borders of the subthalamic nucleus, whereas non-motor symptoms such as anxiety improve with stimulation of the ventral border.