MR-Guided Focused Ultrasound (MRgFUS) for the Management of Tremor in Patients With Multiple Sclerosis

Inclusion Criteria: * Male or Female aged 18-80 years * Willing and able to give consent and attend all study visits * A confirmed diagnosis of medication-refractory, MS-related hand tremor * No clinical evidence of relapse over 12 months or more before enrollment * No MRI activity over 3 months or more before enrollment * Presence of disabling postural or kinetic tremor * Unsatisfactory tremor response to adequate trials of at least two medications * Able to communicate sensations during the treatment * Stable doses of all medications for 30 days prior to and during study Exclusion Criteria: * Severe cerebellar dysfunction measured by Scale for the Assessment and Rating of Ataxia (\>35 out of 40) * Severe weakness or sensory loss in arm contralateral to the side of the brain considered for MRgFUS * Evidence of a superimposed or atypical movement disorder * Unstable cardiac status such as angina pectoris, congestive heart failure, etc. * Severe hypertension * Patients with standard contraindications for MR imaging * History of abnormal bleeding and/or coagulopathy * Ischemic or hemorrhagic stroke within 6 months * Symptoms and signs of increased intracranial pressure (e.g. headache, nausea, vomiting, lethargy, and papilledema) * Untreated, uncontrolled sleep apnea * Active or suspected acute or chronic uncontrolled infection * Receiving anticoagulant or antiplatelet therapy within one week of focused ultrasound procedure or drugs known to increase risk or hemorrhage within one month of MRgFUS surgery * Not able or willing to tolerate the required prolonged stationary supine position during treatment * Participating or have participated in another clinical trial in the last 30 days * Unable to communicate with the investigator and staff * Presence of neurodegenerative disease or significant cognitive impairment * Presence of significant cognitive impairment (≤24 on MMSE) * Uncontrolled major psychiatric disorder or suicidal ideation * Risk factors for intraoperative or postoperative bleeding or documented coagulopathy * Presence of brain tumours * Any illness that in the investigator's opinion preclude participation in this study * Pregnancy or lactation * Legal incapacity or limited legal capacity * Deep Brain Stimulation or a prior stereotactic ablation of the basal ganglia * A history of seizures within the past year