The effect of Deep Brain Stimulation on Electroencephalographic activity and Local Field Potentials in Parkinson’s disease

Deep Brain Stimulation (DBS) of the subthalamic nucleus (STN) and globus pallidus internus (GPi) represents a well-established treatment for patients with advanced Parkinson’s disease (PD) experiencing suboptimal control of symptoms despite optimized pharmacological therapy. By delivering targeted electrical stimulation, DBS is thought to disrupt pathological patterns of neural activity within the basal ganglia and related cortico-basal networks. Despite clinical effectiveness, the neurophysiological mechanisms underlying DBS therapeutic effects remain incompletely understood, given the modulation of both local and wider network-level brain dynamics. This thesis addresses these knowledge gaps by examining the effects of DBS on electroencephalographic (EEG) activity and local field potentials (LFPs) in patients with PD, while also exploring the translational clinical potential of LFPs-based biomarkers across three complementary studies. The first study directly compared beta-band activity in the STN and GPi, providing novel insights into oscillatory signatures across these two main DBS targets in PD, as well as their modulation with stimulation and dopaminergic medication. The second study investigated the effect of both acute and long-term DBS on cortical activity measured with high-density EEG in patients receiving STN- and GPi-DBS, demonstrating how stimulation induces widespread and frequency-specific neurophysiological changes beyond the basal ganglia. The third study explored the translational application of beta-band peaks in LFP recordings for DBS contact selection, highlighting their potential to guide faster, objective and individualized programming strategies.