Explorative investigation on effects of multi-day neurofeedback with implanted electrodes in patients with Parkinson's disease.

Neurofeedback, which consists of recording and visualizing neural activity in real-time, is a method currently being investigated as a supplementary treatment for Parkinson's disease (PD). By using implanted deep brain stimulation (DBS) electrodes with interleaved sensing capability, previous studies have demonstrated the efficacy of neurofeedback based on beta oscillations in the basal ganglia. Herein, for the first time, we explored short-term neurofeedback ability over the course of multiple sessions with a fully implanted DBS system. Eight patients with PD participated in the study. Neurofeedback was established with a fully internalized DBS system using beta oscillations (13-35 Hz, exceptions at 12.7 Hz and 8.78 Hz) from the subthalamic nucleus as visual feedback. Down- and upregulation tasks were performed. Three sessions were conducted on separate days. Neurofeedback induced a significant decline in beta power in the first and third session, while the regulation ability was less pronounced in the second session. In an explorative analysis, an increase in dopaminergic medication induced deterioration of downregulation performance, while stimulation improved the downregulation ability. Changes in the power of gamma oscillations were also induced through beta oscillation neurofeedback, further implying pro-kinetic changes through neurofeedback. This study demonstrated the feasibility of multiple sessions of neurofeedback training with a fully implanted DBS system over several days, however a significant improvement over the cumulative sessions remained absent. Our explorative investigation on possible influencing factors indicates potential improvements of the experimental setup and motivates the use of DBS electrode-guided neurofeedback over extended periods and possibly in an outpatient setting.