Two cases of unexpected long-term improvement of Parkinson's disease after subthalamic nucleus deep brain stimulation removal

Two patients with Parkinson's disease (PD) treated successfully with subthalamic nucleus deep brain stimulation (STN-DBS) for 3-4 years are reported, who demonstrated a persistent improvement following removal of STN-DBS for late infection. Possible hypotheses are discussed--whether a microlesioning effect or a disease-modifying effect of STN-DBS, though neither adequately explain this phenomenon.