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
Aged 22 years or older
Able and willing to give consent and to attend all visits
Diagnosed with essential tremor that is refractory to at least two first-line tremor medications
Confirmed to have moderate-to-severe hand tremor by the MRI guided Focused Ultrasound (MRgFUS) neurology team
Patients with standard contraindications to MRI such as non-MRI compatible implants or devices
Patients deemed clinically unfit to undergo MRgFUS thalamotomy due to health status including (but not limited to) pregnancy, advanced kidney disease, unstable cardiac status, severe hypertension, cerebrovascular disease, brain tumour, pulmonary disorders
Receiving anti-coagulants or drugs known to increase risk of hemorrhage within 2 weeks of MRgFUS procedure
Adults aged 22 years and older with medication-refractory essential tremor and moderate-to-severe hand tremor who are scheduled to undergo MR-guided focused ultrasound (MRgFUS) thalamotomy at Sunnybrook Health Sciences Centre as part of standard of care.
Cohort
Prospective
Not listed
Change in tremor severity measured by Clinical Rating Scale for Tremor (CRST)
CRST is a validated scale assessing tremor severity through clinical examination and functional tasks. Tremor scores range from 0 (no tremor) to 32 for the dominant hand and 0 to 28 for the non-dominant hand, with higher scores indicating greater tremor severity. Change from baseline will be assessed. CRST measures will be videotaped following a standardized script.
Standardized Neurological Examination and Adverse Events (AEs)
Adverse events will be recorded and graded according to CTCAE v5.0. AEs will be recorded and categorized according to severity, and relationship to procedure.
Quality of Life in Essential Tremor (QUEST) questionnaire
The QUEST is a self-reported, validated survey scoring the physical, psychosocial, communication, hobbies/leisure and work/finance domains of the life of a patient with Essential Tremor. Participants rate their level of agreeance with 30 statements on a 5-point scale (0 to 4), for a maximum score of 120. Higher scores reflect poorer quality of life.
Scale for the Assessment and Rating of Ataxia (SARA)
The SARA is a validated, comprehensive ataxia scale, and comprises 8 items carrying a maximum total score of 40 points. Higher scores suggest increased ataxia. The SARA will be used to compare degree of ataxia between baseline and the follow-up visits. In particular, the SARA will be used to assess changes in gait and stance associated with the procedure.
Change in MRI Measures
MRI sequences (T1, T2\*, DTI, resting state fMRI) will be obtained to assess treatment-related changes and safety.
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