P137. Nigral and subthalamic neurostimulation modulate intermuscular coherence in Parkinson’s disease

Abstract

Introduction Combined nigral and subthalamic stimulation is under consideration to modulate otherwise resistant axial motor symptoms, namely freezing of gait in idiopathic Parkinson’s disease (PD). The impact of subthalamic or nigral stimulation on neuromuscular motor integration however needs further characterization. Methods We used fully mobile EEG and EMG recordings, wireless kinematic sensors and video documentation to record patients during a gait cycle. Seven patients with deep brain stimulation were examined both during walking and standing after overnight withdrawal of dopaminergic medications. Recordings in different therapeutic conditions were obtained, i.e. ‘stimulation off’ (StimOff), ‘subthalamic stimulation on’ (STNOn), and ‘nigral stimulation on’ (SNrOn). Results The main finding was an increase of intermuscular coherence in the alpha and low beta bands during ‘walking’ in both STNOn and SNrOn. During ‘standing’ there was increased coherence in theta and alpha bands (‘STNOn’) and in the alpha and low beta bands (‘SNrOn’). Discussion Subthalamic and nigral stimulation increase intermuscular beta band coherence. Intermuscular beta band coherence may reflect increased corticospinal motor control from corticospinal beta drives to the spinal motor unit pool (Marsden et al., 2001; Weiss et al., 2012).