Optimal Fixation Position of Deep Brain Stimulation Electrodes for Parkinson's Disease in Humans

Certain cases of Parkinson’s disease are treated with deep brain stimulation (DBS), applying electrical stimuli to the subthalamic nucleus (STN) in the brain. Stimuli are provided by inserted stimulation electrodes within the brain that supply a square voltage signal generated in a control unit (IPG) typically located in the chest. The elimination of Parkinson’s symptoms depends directly on the location of the stimulation electrodes. This work describes a method used to determine the best fixation position of the stimulation electrodes during surgery. The procedure provides guidance to the surgeon and requires the use of three techniques: 1) use of a stereotactic frame and stereotactic robot, 2) medical imaging (e.g., MRI and CT), and 3) signal analysis provided by microelectrode recording. In DBS surgery, the patient is usually awake with light sedation; however, one of the main advantages of this method is that the patient is fully sedated with anesthesia to avoid any distress or nervousness. Deciding where to perform electrode fixation is a result of combining intraoperative imaging and signal analysis to detect the the electrode position with the highest probability of blocking the PD symptoms. A software tool for signal analysis (DBScan) was developed, assisting the surgical team in determining the location for electrode fixation. In long-term postsurgical analysis, PD disorders were successfully eliminated in all operated patients.