Analysis of Clinical Outcomes in Patients Undergoing Magnetic Resonance-Guided Focused Ultrasound for Medication-Refractory Tremor

The goal of this observational study is to evaluate the long-term efficacy and safety of MR-guided focused ultrasound (MRgFUS) thalamotomy in patients with medication-refractory essential tremor. The main questions it aims to answer are: 1. Does MRgFUS thalamotomy provide sustained reduction in tremor severity over 3 years? 2. What are the long-term neurological and quality-of-life outcomes associated with this procedure? Participants will: * Undergo MRgFUS thalamotomy as part of standard of care at Sunnybrook Health Sciences Centre. * Be followed prospectively for a minimum of 3 years with scheduled assessments including: 1. Clinical Rating Scale for Tremor (CRST) 2. Neurological exams and adverse event monitoring 3. Quality of Life in Essential Tremor (QUEST) questionnaire 4. Scale for the Assessment and Rating of Ataxia (SARA) 5. MRI imaging and neuropsychological testing