Electrophysiological recording in deep brain stimulation: Current status

Abstract

Deep brain stimulation (DBS) is a surgical treatment critical for alleviating symptoms of Parkinson's disease (PD), especially when medication fails to manage motor dysfunctions effectively. The accuracy of electrode placement in the subthalamic nucleus (STN) is critical for the procedure's success. The long-standing debate between electrophysiological recording (MER) and imaging-based targeting remains at the forefront of neurosurgical discussions. MER has traditionally been used to enhance the precision of DBS targeting, indicated by changes in local field potentials (LFPs), which correlate with Parkinsonian motor symptoms such as rigidity, bradykinesia, and tremor. However, the necessity of MER has been questioned due to advances in imaging techniques and the potential risks associated with the practice, including hemorrhage and cognitive decline post-surgery. A critical appraisal of the literature reveals mixed opinions, with recent meta-analyses showing no significant increase in hemorrhage risks with MER but demonstrating a modest increase in adverse cognitive outcomes using multiple electrodes. Despite improved imaging modalities enabling more accurate radiological targeting, MER remains a favored technique among surgeons for its direct feedback on electrode placement. Additionally, the aspect of conducting surgery under awake conditions versus general anesthesia is reviewed, considering the anxiety and discomfort associated with awake surgery against the limitations of performing electrophysiological recordings under general anesthesia. The current consensus underscores the importance of accurate electrode placement, achievable through a combination of MER, test stimulation, and intraoperative imaging, while also acknowledging the growing confidence in image-guided procedures performed under general anesthesia. This review highlights the need for individualized approaches considering patient-specific risks and the evolving landscape of DBS surgery.