Results from a prospectively followed cohort of patients with Parkinson disease (PD) indicate that although deep brain stimulation (DBS) of the subthalamic nucleus is associated with long-term benefits in tremor reduction, it is far less effective for preventing bradykinesia or postural and gait disturbances. These 'nondopaminergic' motor symptoms of PD progressed at approximately the same rate, regardless of DBS, over a follow-up of 6–9 years.