V40. Deep brain recordings using an implanted pulse generator in Parkinson’s disease

Abstract

Introduction Deep brain stimulation (DBS) in the subthalamic nucleus (STN) for Parkinson’s disease (PD) has been shown to be a safe and effective treatment. Recent studies suggest that oscillatory beta activity could be used as a biomarker in patients with PD for subthalamic closed-loop stimulation leading to improved clinical benefit and reduced energy consumption. The aim of the present study was to evaluate the feasibility of local field potential (LFP) recordings for closed-loop stimulation using a new generation of implantable stimulators that also can record LFPs. Materials and methods Eight patients with PD (2 female, mean age 66.1 ± [SEM] 1.5 years; disease duration 10.5 ± 1.4 years) who underwent bilateral implantation of DBS electrodes in the STN were included in the study. LFP recordings were conducted at rest ON and OFF subthalamic high frequency stimulation (140 Hz) via DBS electrodes using the new stimulator device (bipolar recordings from contact pair 0–2, monopolar stimulation at contact 1). FFT based power spectra were calculated ON and OFF DBS, normalized to total power and compared between conditions. Results We recorded subthalamic oscillatory activity from 15 out of 16 DBS electrodes using the stimulator’s sensing function. We found discrete peaks in the beta band in 12 out of 15 electrodes (mean peak frequency 17 Hz). A significant reduction in averaged beta band power (13–30 Hz) of 14% was found ON compared to OFF DBS condition ( p = 0.002). No difference was found in the alpha band (7–13 Hz; p > 0.05). Direct comparison of beta peak frequency aligned power spectra across the group revealed a significant DBS related beta power reduction in a frequency range from −1.4 Hz to +5.8 Hz ( p ⩽ 0.03, FWE corrected) surrounding the individual peaks. Discussion We demonstrate for the first time recordings of human deep brain activity from a new generation of fully implantable pulse generators with sensing function. Discrete peaks in beta activity were obtained from the subthalamic area from 12 out of 15 electrodes when patients were OFF medication, moreover the new device could identify a significant suppression of beta band activity during DBS. The present results give further evidence for beta band activity being a useful biomarker in PD patients that can be followed with implantable systems.