Deep Brain Stimulation (DBS) for the Suppression of Tremor

Study Overview
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Brief Summary
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The purpose of the proposed study is to demonstrate the safety and efficacy of the ANS Totally Implantable Deep Brain Stimulation System in the VIM nucleus of the thalamus implanted for the treatment of tremor due to essential tremor. This study will be included in the Pre-Market Approval Application to support the safety of this device in use.

Detailed Description
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This study is designed as a prospective, multi-centered study for 365 days in duration from device implantation. A maximum of 12 sites will enroll 160 patients. Each patient will be screened and then undergo a baseline evaluation followed by unilateral or bilateral implantation of the DBS system. During the implantation procedure, each patient will undergo a trial of stimulation in the operating room. The device may be internalized after a successful intra-operative trial or at a later surgery (no later than 4 weeks after initial lead placement). If the device is not activated immediately postsurgery, the patient may return to the clinic to determine optimum stimulation programming. Device programming will be optimized in as many visits as necessary following implantation. The day that the device is fully implanted will be classified as Day 0 for each patient. After Day 0 the patient will return to clinic for evaluations at, Day 90 (±14 days), and Day 180 (±14 days) and Day 365 (approximately 12 months ± 30 days after Day 0). These evaluations consist of the CRST, the QUEST, the SF36, Patient and caregiver Global Ratings and the Patient Satisfaction Rating. At Baseline and Day 180, the CRST evaluation session will be video recorded for analysis by an independent evaluator unaware of the functioning of the device. Additionally, at the Day 180 visit, the physician will have the option to provide the patient with amplitude control. A comparison of measures within the same person from pre-treatment to post-treatment will be performed. Also, pre-treatment and post-treatment group means and standard deviations will be determined. Patients completed follow-up visits as part of the original protocol (C-04-02) for one year (or in some cases longer if patient was bilaterally implanted) and continued to complete additional visits as part of the Long-Term Follow-up protocol (C-06-03) for up to 5 years post implant.

Official Title
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A Clinical Evaluation of the Advanced Neuromodulation System (ANS) Totally Implantable Deep Brain Stimulation System for the Suppression of Tremor in the Upper Extremities of Patients With Essential Tremor.

Conditions
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Tremor, Action Tremor, Essential Tremor, Tremor, Limb

Intervention / Treatment
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* Device: ANS Totally Implantable Deep Brain Stimulation System


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: Patient or authorized representative has signed an informed consent. Patient is over 18 years of age. Patient is diagnosed with essential tremor for at least 3 years. Patient has a disabling medical-refractory upper extremity tremor with no evidence of supraspinal central nervous system disease or injury (tremor not adequately controlled by medications for at least three (3) months before implant). Patient has a postural or kinetic tremor severity score of at least 3 out of 4 in the extremity intended for treatment on the Fahn-Tolosa-Marin Clinical Rating Scale for Tremor. Patient will maintain a constant dose of anti-tremor medication indicated as best medical management for one (1) month prior to enrollment in study. Patient is available for appropriate follow-up times for the length of the study. Exclusion criteria: Patient is not surgical candidate; Patient has other clinically or medically significant disease; Patient has any neurological injury or disease other than essential tremor; Patient has any condition requiring repeated MRI scans; Patient has any condition requiring diathermy; Patients on anticoagulant medications; Patient has untreated clinically significant depression; Patient has had an electrical or electromagnetic implant (cochlear prosthesis, pacemaker etc); Patient has had a prior thalamotomy or surgical ablation procedure in either side of the brain; Patient has dementia interfering with their ability to co-operate or comply with study requirements or comprehend the informed consent (mini-mental exam score <24); Patient abuses drugs or alcohol; Patient has had botulinum toxin injections in the six (6) months prior to enrollment; Patient has a history of cranial surgery; Patient has a history of seizures; Patient has any metallic implants that may interfere with the functioning of the device (e.g. aneurysm clips); Patient has a history of stimulation intolerance in any area of the body; Patient is a female of child bearing potential with a positive urine pregnancy test or not using adequate contraception.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Stimulation<br>ANS Totally Implantable Deep Brain Stimulation System | Device: ANS Totally Implantable Deep Brain Stimulation System<br>* ANS Totally Implantable Deep Brain Stimulation System will be implanted in the VIM nucleus of the thalamus<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Primary Efficacy Endpoint: Difference in the Postural Tremor Score of the Target Limb Between Stimulation On and Stimulation Off, As Assessed by the Blind Reviewer | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. | Day 180 | 
| Primary Safety Endpoint: Percentage of Participants With Device-related or Procedure Related Adverse Events | Percentage of device-related or procedure related adverse events will be assessed within 6 months following the initial unilateral implant. All such adverse events will be counted for 180 days following surgery or until the day of the second implant, which ever comes first. | Within 180 days following the initial implant | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Target Limb Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Target Limb Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Target Limb Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Target Limb Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Target Limb Responder Analysis, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. During responder analysis, a 2-point reduction in kinetic tremor or postural tremor between stimulation Off and stimulation On show an improvement in activities of daily living was considered a response, was also performed using the site physician's ratings. | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Target Limb Responder Analysis, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. During responder analysis, a 2-point reduction in kinetic tremor or postural tremor between stimulation Off and stimulation On show an improvement in activities of daily living was considered a response, was also performed using the site physician's ratings. | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Target Limb Responder Analysis, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. During responder analysis, a 2-point reduction in kinetic tremor or postural tremor between stimulation Off and stimulation On show an improvement in activities of daily living was considered a response, was also performed using the site physician's ratings. | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Handwriting for Target Side Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's handwriting according to the CRST (scale 0-4). | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Handwriting for Target Side Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's handwriting according to the CRST (scale 0-4). | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Handwriting for Target Side Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's handwriting according to the CRST (scale 0-4). | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Handwriting for Target Side Severity Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's handwriting according to the CRST (scale 0-4). | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Handwriting for Target Side Severity Score, As Assessed by the Blind Reviewer | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The blind reviewer will evaluate the patient's handwriting according to the CRST (scale 0-4). | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Pouring From Target Side Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's pouring ability according to the CRST | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Mean Pouring From Target Side Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's pouring ability according to the CRST | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Pouring From Target Side Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's pouring ability according to the CRST | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Mean Pouring From Target Side Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The site physician will evaluate the patient's pouring ability according to the CRST | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Pouring Ability From Target Side Severity Scores, As Assessed by the Blind Reviewer | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The blind reviewer will evaluate the patient's pouring ability according to the CRST | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Total Motor Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The motor score adds together all responses to the tremor assessment for questions 1-9 of the CRST (whether or not the specific side is being treated). | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Total Motor Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The motor score adds together all responses to the tremor assessment for questions 1-9 of the CRST (whether or not the specific side is being treated). | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Total Motor Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The motor score adds together all responses to the tremor assessment for questions 1-9 of the CRST (whether or not the specific side is being treated). | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Mean Total Motor Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The motor score adds together all responses to the tremor assessment for questions 1-9 of the CRST (whether or not the specific side is being treated). | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Activity of Daily Living Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The activity of daily living score adds together all responses to questions 15-21 of the CRST. | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Activity of Daily Living Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The activity of daily living score adds together all responses to questions 15-21 of the CRST. | Day 90 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Activity of Daily Living Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The activity of daily living score adds together all responses to questions 15-21 of the CRST. | Day 180 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation- Activity of Daily Living Score, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. The activity of daily living score adds together all responses to questions 15-21 of the CRST. | Day 365 | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Bilateral Stimulation, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. For those patients that had bilateral stimulation, the site physician will evaluate the patient's non-target side after 180 days of bilateral stimulation. | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Bilateral Stimulation, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. For those patients that had bilateral stimulation, the site physician will evaluate the patient's non-target side after 180 days of bilateral stimulation. | Following 180 days of stimulation | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Non-Target Limb Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. For those patients that had bilateral stimulation, the site physician will evaluate the patient's non-target side after 180 days with only the second side system On | Baseline | 
| Clinical Rating Scale for Tremor (CRST) Evaluation-Non-Target Limb Severity Scores, As Assessed by the Site Physician | The Fahn, Tolosa, Marin Tremor Rating Scale (referred to as the CRST), is a rating tool to assess the severity of postural, isometric, kinetic and task specific tremor in the dominant and non-dominant sides of the head, trunk and limbs of patients with ET. The CRST utilizes a 0 to 4 point scale where 0 indicates non-symptomatic (normal) and 4 indicates the most severe rating of the patient's tremor symptoms. For those patients that had bilateral stimulation, the site physician will evaluate the patient's non-target side after 180 days with only the second side system On | Following 180 days of stimulation | 
| Quality of Life in Essential Tremor (QUEST): Overall Summary Index | The QUEST questionnaire consists of 30 items, which are rated from 0 to 4, corresponding to the frequency (from never to always). Those 30 items assess how tremor impacts a function or how it can be associated with feelings or attitudes. The 30 items contribute to five sub scales (number of items contributing to each scale in parentheses): Physical/ADL (9), Psychosocial (9), Communication (3), Hobbies/Leisure (3), and Work/Finances (6). The score on each sub scale is expressed as a percentage of the total score possible, with a higher score indicating greater dissatisfaction with that domain of QOL. As the scores were expressed as percentages, if a question was unanswered it was excluded and percentages were calculated based on the remaining answers. A total or quest summary index (QSI) was computed by calculating the mean of the five scales. Maximal score of 100 indicates worse quality of life, while minimal score 0 corresponds to best quality of life. | Baseline | 
| Change From Baseline for Quality of Life in Essential Tremor (QUEST): Overall Summary Index | The QUEST questionnaire consists of 30 items, which are rated from 0 to 4, corresponding to the frequency (from never to always). Those 30 items assess how tremor impacts a function or how it can be associated with feelings or attitudes. The 30 items contribute to five sub scales (number of items contributing to each scale in parentheses): Physical/ADL (9), Psychosocial (9), Communication (3), Hobbies/Leisure (3), and Work/Finances (6). The score on each sub scale is expressed as a percentage of the total score possible, with a higher score indicating greater dissatisfaction with that domain of QOL. As the scores were expressed as percentages, if a question was unanswered it was excluded and percentages were calculated based on the remaining answers. A total or quest summary index (QSI) was computed by calculating the mean of the five scales. Maximal score of 100 indicates worse quality of life, while minimal score 0 corresponds to best quality of life. | Day 90 | 
| Change From Baseline for Quality of Life in Essential Tremor (QUEST): Overall Summary Index | The QUEST questionnaire consists of 30 items, which are rated from 0 to 4, corresponding to the frequency (from never to always). Those 30 items assess how tremor impacts a function or how it can be associated with feelings or attitudes. The 30 items contribute to five sub scales (number of items contributing to each scale in parentheses): Physical/ADL (9), Psychosocial (9), Communication (3), Hobbies/Leisure (3), and Work/Finances (6). The score on each sub scale is expressed as a percentage of the total score possible, with a higher score indicating greater dissatisfaction with that domain of QOL. As the scores were expressed as percentages, if a question was unanswered it was excluded and percentages were calculated based on the remaining answers. A total or quest summary index (QSI) was computed by calculating the mean of the five scales. Maximal score of 100 indicates worse quality of life, while minimal score 0 corresponds to best quality of life. | Day 180 | 
| Change From Baseline for Quality of Life in Essential Tremor (QUEST): Overall Summary Index | The QUEST questionnaire consists of 30 items, which are rated from 0 to 4, corresponding to the frequency (from never to always). Those 30 items assess how tremor impacts a function or how it can be associated with feelings or attitudes. The 30 items contribute to five sub scales (number of items contributing to each scale in parentheses): Physical/ADL (9), Psychosocial (9), Communication (3), Hobbies/Leisure (3), and Work/Finances (6). The score on each sub scale is expressed as a percentage of the total score possible, with a higher score indicating greater dissatisfaction with that domain of QOL. As the scores were expressed as percentages, if a question was unanswered it was excluded and percentages were calculated based on the remaining answers. A total or quest summary index (QSI) was computed by calculating the mean of the five scales. Maximal score of 100 indicates worse quality of life, while minimal score 0 corresponds to best quality of life. | Day 365 | 
| SF36 Components and Individual Domains | The SF-36 questionnaire is a measure of health status with 36 items across 8 domains. The eight domains are separated into two summary scores of four domains, the physical component summary (PCS) and mental component summary (MCS). The SF-36 score is transformed into a scale of 0-100, with 100 indicating no disability. PCS and MCS are scaled in comparison to population norms to reflect a mean of 50 and standard deviation of 10 for the general population of the United States. | Baseline | 
| SF36 Components and Individual Domains | The SF-36 questionnaire is a measure of health status with 36 items across 8 domains. The eight domains are separated into two summary scores of four domains, the physical component summary (PCS) and mental component summary (MCS). The SF-36 score is transformed into a scale of 0-100, with 100 indicating no disability. PCS and MCS are scaled in comparison to population norms to reflect a mean of 50 and standard deviation of 10 for the general population of the United States. | Day 90 | 
| SF36 Components and Individual Domains | The SF-36 questionnaire is a measure of health status with 36 items across 8 domains. The eight domains are separated into two summary scores of four domains, the physical component summary (PCS) and mental component summary (MCS). The SF-36 score is transformed into a scale of 0-100, with 100 indicating no disability. PCS and MCS are scaled in comparison to population norms to reflect a mean of 50 and standard deviation of 10 for the general population of the United States. | Day 180 | 
| SF36 Components and Individual Domains | The SF-36 questionnaire is a measure of health status with 36 items across 8 domains. The eight domains are separated into two summary scores of four domains, the physical component summary (PCS) and mental component summary (MCS). The SF-36 score is transformed into a scale of 0-100, with 100 indicating no disability. PCS and MCS are scaled in comparison to population norms to reflect a mean of 50 and standard deviation of 10 for the general population of the United States. | Day 365 | 
| Global Assessment Scores by Examiner | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the examiner's interpretation of the patient's quality of life. | Baseline | 
| Global Assessment Scores by Examiner | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the examiner's interpretation of the patient's quality of life. | Day 90 | 
| Global Assessment Scores by Examiner | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the examiner's interpretation of the patient's quality of life. | Day 180 | 
| Global Assessment Scores by Examiner | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the examiner's interpretation of the patient's quality of life. | Day 365 | 
| Global Assessment by Caregiver | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the caregiver's interpretation of the patient's quality of life | Baseline | 
| Global Assessment by Caregiver | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the caregiver's interpretation of the patient's quality of life | Day 90 | 
| Global Assessment by Caregiver | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the caregiver's interpretation of the patient's quality of life | Day 180 | 
| Global Assessment by Caregiver | Global outcome measures are a self-rated questionnaire that measures a global assessment of the patient quality of life and the caregiver's interpretation of the patient's quality of life | Day 365 | 
| Global Assessment by Patient | Global outcome measures are a self-rated questionnaire in which patients assess their own global outcome at each visit | Baseline | 
| Global Assessment by Patient | Global outcome measures are a self-rated questionnaire in which patients assess their own global outcome at each visit | Day 90 | 
| Global Assessment by Patient | Global outcome measures are a self-rated questionnaire in which patients assess their own global outcome at each visit | Day 180 | 
| Global Assessment by Patient | Global outcome measures are a self-rated questionnaire in which patients assess their own global outcome at each visit | Day 365 | 
| Subjective Assessment by Patient Since Activation of System | Subjective assessment includes changes in their ET symptoms since the last visit indicated as marked improvement, moderate improvement, mild improvement, worsening, or no change. | Day 90 | 
| Subjective Assessment by Patient Since Activation of System | Subjective assessment includes changes in their ET symptoms since the last visit indicated as marked improvement, moderate improvement, mild improvement, worsening, or no change. | Day 180 | 
| Subjective Assessment by Patient Since Activation of System | Subjective assessment includes changes in their ET symptoms since the last visit indicated as marked improvement, moderate improvement, mild improvement, worsening, or no change. | Day 365 | 
| Number of Participants With Satisfaction With the DBS System's Functioning and Ability to Control Symptoms | At each visit, patients will be asked about their satisfaction with the DBS system's functioning and ability to control symptoms | Day 90 | 
| Number of Participants With Satisfaction With the DBS System's Functioning and Ability to Control Symptoms | At each visit, patients will be asked about their satisfaction with the DBS system's functioning and ability to control symptoms | Day 180 | 
| Number of Participants With Satisfaction With the DBS System's Functioning and Ability to Control Symptoms | At each visit, patients will be asked about their satisfaction with the DBS system's functioning and ability to control symptoms | Day 365 | 
| Number of Participants Who Would Choose to Receive the DBS System Again | At each visit, patients will be asked if they would undergo the DBS procedure again | Day 90 | 
| Number of Participants Who Would Choose to Receive the DBS System Again | At each visit, patients will be asked if they would undergo the DBS procedure again | Day 180 | 
| Number of Participants Who Would Choose to Receive the DBS System Again | At each visit, patients will be asked if they would undergo the DBS procedure again | Day 365 | 
| Number of Participants Who Would Recommend the DBS System | At each visit, patients will be asked if they would recommend the DBS system to others | Day 90 | 
| Number of Participants Who Would Recommend the DBS System | At each visit, patients will be asked if they would recommend the DBS system to others | Day 180 | 
| Number of Participants Who Would Recommend the DBS System | At each visit, patients will be asked if they would recommend the DBS system to others | Day 365 | 
| Beck Depression Inventory II (BDI - II) Score for Depression Symptoms | The Beck Depression Inventory II is A clinical rating scale designed for detecting depression based on the Diagnostic and Statistical Manual of Mental Health Disorders-Fourth Edition (DSM-IV) criteria. This widely used instrument consists of 21 items to assess the intensity of depression in clinical and normal patients. Each item is a list of four statements arranged in increasing severity about a particular symptom of depression. The BDI II questionnaire contains 21 questions, each answer being scored on a scale value of 0 to 3. A score between 0-13 indicates minimal depression, 14-19 mild depression, 20-28 moderate depression and 29-63 severe depression. Total scores are obtained by computing the sum of each score. The scores range from 0 to 63, with higher score indicating greater severity of depressive symptoms. | Baseline | 
| Change From Baseline in Beck Depression Inventory II (BDI - II) Score for Depression Symptoms | The Beck Depression Inventory II is A clinical rating scale designed for detecting depression based on the Diagnostic and Statistical Manual of Mental Health Disorders-Fourth Edition (DSM-IV) criteria. This widely used instrument consists of 21 items to assess the intensity of depression in clinical and normal patients. Each item is a list of four statements arranged in increasing severity about a particular symptom of depression. The BDI II questionnaire contains 21 questions, each answer being scored on a scale value of 0 to 3. A score between 0-13 indicates minimal depression, 14-19 mild depression, 20-28 moderate depression and 29-63 severe depression. Total scores are obtained by computing the sum of each score. The scores range from 0 to 63, with higher score indicating greater severity of depressive symptoms. | Day 365 | 
| Mini Mental State Exam (MMSE) for Examination of Mental Status | The Mini-Mental State Examination (MMSE) is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. It examines functions including registration (repeating named prompts), attention and calculation, recall, language, ability to follow simple commands and orientation. Any score of 24 or more (out of 30) indicates a normal cognition. | Baseline | 
| Change From Baseline in Mini Mental State Exam (MMSE) For Examination of Mental Status | The Mini-Mental State Examination (MMSE) is a 30-point questionnaire that is used extensively in clinical and research settings to measure cognitive impairment. It examines functions including registration (repeating named prompts), attention and calculation, recall, language, ability to follow simple commands and orientation. Any score of 24 or more (out of 30) indicates a normal cognition. | Day 365 |