A Study to Evaluate the Safety and Efficacy of ExAblate Subthalomotomy for the Treatment of Parkinson's Disease Motor Features

Exclusion Criteria

• •1. Hoehn and Yahr stage in the ON medication state of 2.5 or greater
• •2. Presence of severe dyskinesia as noted by a score of 3 or 4 on questions 4.1 and 4.2 of the MDS-UPDRS.
• •3. Presence of other central neurodegenerative disease suspected on neurological examination. These include: multisystem atrophy, progressive supranuclear palsy, corticobasal syndrome, dementia with Lewy bodies, and Alzheimer's disease.
• •4. Any suspicion that Parkinsonian symptoms are a side effect from neuroleptic medications.
• •5. Subjects who have had deep brain stimulation or a prior stereotactic ablation of the basal ganglia
• •6. Presence of significant cognitive impairment defined as score ≤ 21 on the Montreal Cognitive Assessment (MoCA) or Mattis Dementia Rating Scale of 120 or lower.
• •7. Unstable psychiatric disease, defined as active uncontrolled depressive symptoms, psychosis, delusions, hallucinations, or suicidal ideation. Subjects with stable, chronic anxiety or depressive disorders may be included provided their medications have been stable for at least 60 days prior to study entry and if deemed appropriately managed by the site neuropsychologist
• •8. Subjects with significant depression as determined following a comprehensive assessment by a neuropsychologist. Significant depression is being defined quantitatively as a score of greater than 14 on the Beck Depression Inventory.
• •9. Legal incapacity or limited legal capacity as determined by the neuropsychologist
• •10. Subjects exhibiting any behavior(s) consistent with ethanol or substance abuse as defined by the criteria outlined in the DSM-IV as manifested by one
• •11. Subjects with unstable cardiac status including
• •12. Severe hypertension (diastolic BP \> 100 on medication).
• •13. History of or current medical condition resulting in abnormal bleeding and/or coagulopathy.
• •14. Receiving anticoagulant (e.g. warfarin) or antiplatelet (e.g. aspirin) therapy within one week of focused ultrasound procedure or drugs known to increase risk or hemorrhage (e.g. Avastin) within one month of focused ultrasound procedure
• •15. Subjects with risk factors for intraoperative or postoperative bleeding as indicated by: platelet count less than 100,000 per cubic millimeter, a documented clinical coagulopathy, or INR coagulation studies exceeding the institution's laboratory standard
• •16. Patient with severely impaired renal function with estimated glomerular filtration rate \<30mL/min/1.73m2 (or per local standards should that be more restrictive) and/or who is on dialysis;
• •17. Subjects with standard contraindications for MR imaging such as non-MRI compatible implanted metallic devices including cardiac pacemakers, size limitations, etc.
• •18. Significant claustrophobia that cannot be managed with mild medication.
• •19. Subject who weight more than the upper weight limit of the MR table and who cannot fit into the MR scanner
• •20. Subjects who are not able or willing to tolerate the required prolonged stationary supine position during treatment.
• •21. History of intracranial hemorrhage
• •22. History of multiple strokes, or a stroke within past 6 months
• •23. Subjects with a history of seizures within the past year
• •24. Subjects with malignant brain tumors
• •25. Subjects with intracranial aneurysms requiring treatment or arterial venous malformations (AVMs) requiring treatment.
• •26. Any illness that in the investigator's opinion preclude participation in this study.
• •27. Subjects unable to communicate with the investigator and staff.
• •28. Pregnancy or lactation.
• •29. Subjects who have an Overall Skull Density Ratio lower than 0.35 as calculated from the screening CT.