Karlsson F, et al. - During this research, the effect of deep brain stimulation (DBS) in the subthalamic nucleus (STN) and caudal zona incerta (cZi) on the level of perceived voice tremor was comprehensively investigated in patients with Parkinson's disease (PD). It was seen that the perceived voice tremor on a group level decreased due to STN-DBS. In patients with PD displaying moderate to severe preoperative levels of the symptom, cZi-DBS decreased the perceived voice tremor.