Ten Hertz thalamus stimulation increases tremor activity in the subthalamic nucleus in a patient with Parkinson’s disease

Objective In patients with Parkinson’s disease (PD) the effect of thalamic stimulation on tremor pathophysiology remains largely unclear. By recording local field potentials (LFPs) in the subthalamic nucleus (STN) while stimulating the nucleus ventralis intermedius thalami (VIM), information of the stimulation effects should be gained. Methods We had the unique opportunity to intraoperatively record LFPs of the STN in a patient with PD while stimulating the VIM. VIM electrodes had been implanted 9 years previously because of tremor. Due to worsening of clinical symptoms an implantation of STN electrodes had become necessary. Results High frequency stimulation in the VIM lowered the power of the tremor frequency band (4–7 Hz) in the STN. In contrast, 10 Hz VIM stimulation elevated the power of the tremor frequency band as well as STN–EMG coupling. Conclusions The effect of high frequency stimulation may explain the improvement of tremor in patients who are treated with VIM deep brain stimulation. The power elevation during 10 Hz stimulation suggests that the pathological cerebral and cerebral–muscular communication in PD is mainly driven at 10 Hz. Significance The direct cerebral recordings support the view that a 10 Hz network is a pathophysiological key mechanism in the generation of motor deficits in PD