Subthalamic Nucleus (STN)-Deep Brain Stimulation Reduces the Power of Mu and Beta Rhythms and Enhances Synchrony at the Motor Cortices in Parkinson's Disease: A Report of Two Cases

The motor circuit in Parkinson’s disease (PD) involves the basal ganglia, thalamus, motor cortex, and cerebellum. Hence, subthalamic nucleus (STN) or globus pallidus internus deep brain stimulation is commonly used in treating refractory Parkinson’s patients. During the procedure, the local field potential (LPF) is commonly made along the trajectory of the STN. Two cases were assessed, where an electroencephalographic recording at the sensorimotor cortices was also performed with and without stimulation at the optimal STN electrode site. The ‘on’ stimulation state associated with clinical improvement correlated with a marked reduction in the late theta (7.5 Hz), alpha (10.5 Hz) (Mu wave), and beta (20 Hz) wave power. Besides, more synchronized and coherent brainwaves were noted when the stimulation was ‘on’.