Intraoperative local field recording for deep brain stimulation in Parkinson's disease and essential tremor

Oscillations in the beta frequency range (β-LFP) are widely distributed throughout the motor system, modulated by dopaminergic medications, and locally generated in the subthalamic nucleus (STN) and ventral intermediate nucleus of the thalamus (VIM). We investigated the feasibility of recording intraoperative β-LFP signals and their descriptive summary statistics during surgeries for deep brain stimulation (DBS). β-LFP from the microelectrode and stimulating lead were obtained from the STN in Parkinson's patients, and from the stimulating lead in the VIM of patients with Parkinson's disease or essential tremor. β-LFP power was obtained over 8 second epochs and displayed online as compressed spectral and density arrays and trend plots. In agreement with other studies, β-LFP power along microelectrode penetrations was greater in the STN as compared to sites dorsal and ventral to the nucleus. Differences in β-LFP power were also observed across the contacts of stimulating leads in the STN and VIM. The contact with greatest β-LFP power was either the most effective contact for clinical stimulation or adjacent to it. These results were obtained from conventional power measurements, spectral displays, and trend plots with equipment commonly used for intraoperative neuromonitoring. We conclude that β-LFP is an accessible and easily recorded signal intraoperatively with potential usefulness for DBS lead localization and clinical programming of the stimulating lead.