Cyclic Deep Brain Stimulation in Essential Tremor

Study Overview
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Brief Summary
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The aim of the study is to prove the efficacy and safety of cyclical deep brain stimulation (DBS) in patients with essential tremor, and demonstrate non-inferiority of cyclical DBS on tremor control when compared to continuous stimulation.

Detailed Description
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This study is a prospective, randomized, double-blind cross-over trials. Patients will be randomized into two groups in a cross-over fashion to have either continuous or cyclical stimulation for a total of three months. Following this, the trial will be unblinded and open-label follow up will continue for another nine months. Device use as per standard practice continues after the end of the trial. If the hypothesis is proven correct, this will provide proof of concept that cyclical stimulation for the treatment of essential tremor results in improved battery life, reduced number of operations for battery changes, reduction in stimulation side-effects and enhancing quality of life.

Official Title
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Cyclic Versus Continuous Deep Brain Stimulation in Essential Tremor

Conditions
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Essential Tremor

Intervention / Treatment
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* Device: Abbott St Jude Medical Infinity 7 neurostimulator


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant is at least 18 years of age Participant has confirmed diagnosis of medically-refractory essential tremor Participant meets criteria for implantation of DBS system Participant understands the study requirements and treatments procedures and provides informed consent before any study-specific tests or procedures are performed Exclusion Criteria: Participant meets any contraindications for implantation of DBS system Participant is undergoing or has had previous thalamic stimulation either in a research trial or with a permanent implant Participant is unwilling or unable to comply with all study required follow-up evaluations

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Patients will be randomized into 2 groups with either cyclical or continuous stimulation. Patients will cross-over to the 2nd mode of stimulation after 1 month and then continued on the preferred mode of stimulation for the 3rd month. Open label follow-up starts at this point and continues for another 9 months.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cyclical Stimulation<br>This group will undergo cyclical stimulation mode of stimulation | Device: Abbott St Jude Medical Infinity 7 neurostimulator<br>* The stimulator has the capability to deliver both continuous and cyclical modes of stimulation which is being investigated in this study<br>|
| Active Comparator: Continuous Stimulation<br>This group will undergo the standard continuous mode of stimulation | Device: Abbott St Jude Medical Infinity 7 neurostimulator<br>* The stimulator has the capability to deliver both continuous and cyclical modes of stimulation which is being investigated in this study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fahn-Tolosa-Marin Tremor Rating Scale - total score difference | Change in Fahn-Tolosa-Marin tremor rating scale at 6 months compared to baseline. Minimum score is 0 and maximum score is 84. Higher scores indicate worse tremor control | 6 months compared to baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EuroQol five dimensions questionnaire (EQ-5D) difference | The total score of EQ-5D questionnaire at 6 months compared to baseline. Each dimension of the questionnaire has a minimum score of 1 and a maximum score of 5. Higher composite scores indicate increased levels of perceived problems | 6 months post activation compared to baseline | 
| Beck's Depression Index questionnaire difference | The total score of Beck's Depression Index questionnaire at 6 months compared to baseline. The minimum score is 0 and maximum score is 63. Higher scores indicate increasing severity of depression | 6 months post activation compared to baseline | 
| Quality of Life in Essential Tremor (QUEST) questionnaire difference | The total score of Quality of Life in Essential Tremor questionnaire at 6 months compared to baseline. Minimum score is 0 and maximum score is 120 with higher scores indicating worse quality of life due to tremor | 6 months post activation compared to baseline | 
| Satisfaction with Treatment (SWT) questionnaire difference | The difference in Satisfaction with Treatment outcomes at 6 months compared to baseline | 6 months post activation compared to baseline | 
| Clinical Global Impression of Change (CGI) difference | The difference in Clinical Global Impression of change outcome at 6 months compared to baseline | 6 months post activation compared to baseline | 
| Implantable Pulse Generator (IPG) power consumption and longevity | Total amount of implantable pulse generator consumption used compared between the 2 groups | 6 months compared to baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Essential Tremor, Deep Brain Stimulation