Can chronic subthalamic nucleus stimulation induce de novo tremor in Parkinson's disease?

Subthalamic nucleus stimulation dramatically improves parkinsonian symptoms, notably the tremor. The occurrence of a tremor in the first 6 months after the surgical procedure in patients without tremor preoperatively is much less common. We report on the cases of 3 patients who developed such modification of their parkinsonian symptomatology. Physiopathological hypotheses are discussed.