P181. Effects of deep brain stimulation on cortical activity during a motor task in patients with Parkinson’s disease – A functional near-infrared spectroscopy (fNIRS) study

Abstract

Subthalamic nucleus deep brain stimulation (DBS) has become a standard neurosurgical therapy for advanced Parkinson’s disease which can dramatically improve the motor symptoms of patients. Although this procedure targets subcortical brain regions, possible effects on cortical areas have also been discussed. Nevertheless, such cortical effects of DBS are so far largely unexplored. Due to its insensitivity to electrical environmental signals, functional near-infrared spectroscopy (fNIRS) uniquely offers the possibility to directly assess potential cortical effects of DBS. Against this background, the present study investigated cortical activation changes in response to DBS in patients with Parkinson’s disease (PD) using fNIRS. To this end, 13 PD patients performed a simple motor task consisting of alternating active (pressing a softball with the right hand at 0.33 Hz) and inactive (no press) task blocks. Hereby, the paradigm consisted of two runs, one run with active DBS and one run without stimulation, respectively. Prefrontal and fronto-parietal cortical activation changes were measured throughout the entire experiment by means of 44-channel-fNIRS recordings. During active DBS, we observed an increase in left-frontal brain activation during the active motor blocks (ball press) as compared to the inactive blocks (no press). We conclude that subthalamic nucleus DBS is, in addition to direct subcortical effects, associated with changes in frontal cortical activity, which can be directly assessed using fNIRS. In the long run, such measurements can beneficially support the selection, monitoring, and optimizing of stimulation parameters in DBS treatment.