The aim of this study is to compare the effectiveness of the deep brain stimulation in the posterior subthalamic area (PSA) versus the subthalamic nucleus (STN) for the treatment of dystonic tremor (DT) in a randomized, double-blinded, cross-over manner.

This is a randomized, double-blinded, crossover trial aiming at comparing the efficacy of PSA and STN DBS in treating dystonic tremor. Enrolled patients will undergo bilateral DBS surgery, targeting both PSA and STN with single trajectory. Three months post-implantation, patients enter a 4-month double-blinded crossover phase with PSA and STN DBS in randomized order. After 7 months post-implantation (at the end of the crossover phase), patients enter an open-label phase during which programming parameters are not restricted until the termination of the study at 12-month follow-up.

Inclusion Criteria:

• Diagnosed with dystonic tremor based on the MDS 2018 consensus
• Duration of DT symptoms: ≥3 years of motor symptoms
• If the patient is taking tremor medications, the medications should be stable for 28 days prior to informed consent
• Good compliance and written informed consent

Exclusion Criteria:

• Any intracranial abnormalities that would prevent DBS surgery
• Any significant mental illness that might affect the subject's ability to comply with the study protocol requirements (e.g., bipolar disorder, schizophrenia, mood disorders with psychotic features, Cluster B personality disorders)
• Severe cognitive impairment, MOCA score <24
• Any current substance or alcohol abuse according to DSM-V criteria
• Any history of recurrent or unprovoked epileptic seizures; any prior movement disorder treatment involving intracranial surgery or device implantation; any history of hemorrhagic stroke; any significant medical condition that might interfere with the study procedures or could confound the assessment of study endpoints
• Any terminal illness with a life expectancy of <1 year