A Prospective, Randomized, Controlled Trial to Test Safety and Effectiveness of Unilateral Exablate MR-guided Focused Ultrasound Subthalamotomy in Patients With Early-Stage Parkinson's Disease

Inclusion Criteria: * Men and women; age 30 to 65 years old * Subjects who are able and willing to give consent and able to attend all study visits. - Subjects with a diagnosis of PD according to the modified clinical criteria by the Movement Disorders Society, for less than 5 years and more than 12 months. * Off-medication MDS-UPDRS part III of the most affected body side ≥ 10 * Motor signs predominantly present in one body side: Asymmetry index (MDS-UPDRS III of the most affected side/MDS-UPDRS III of the least effected side) ≥ 2. * Patients should have a stable pharmacological regime for the last 4-weeks prior to baseline evaluation. * Topographic coordinates of the subthalamic nucleus are localizable on MRI so that it can be targeted by the Exablate device. * Skull density ratio (SDR) score of 0.40 or higher\*. The SDR is a determinant factor for the suitability to MRgFUS ablation. SDR is a ratio of ultrasound energy penetration through the skull. The SDR threshold for using Exablate 4000 is established at 0.4 with patients having SDR below that value considered unsuitable candidates. * Able to communicate sensations during the Exablate MRgFUS treatment. Exclusion Criteria: * MDS-UPDRS part III OFF medications \> 32 in the off state and/or Hoehn and Yahr state ON medication greater than 2. * Significative evidence (by clinical history) of having developed features indicative of PD motor onset 2 or more years prior to formal diagnosis. * Presence of clinically relevant …