Demand-driven Management of Essential Tremor

Study Overview
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Brief Summary
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This study evaluates the effectiveness of tremor control using various strategies for implementing demand-driven thalamic deep brain stimulation (DBS) for essential tremor. Therapeutic stimulation at the Vim nucleus of the thalamus will be initiated and modulated using signals derived from external sensors (e.g. EMG, accelerometer) and cortical or thalamic electrodes.

Detailed Description
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Essential tremor is effectively treated with deep brain stimulation of the ventralis intermedius nucleus of the thalamus, presumably because high-frequency stimulation disrupts aberrant cerebellar-thalamic input. For the most part, patients with essential tremor have a kinetic tremor that is present or worsened with movement. However, DBS therapy is currently continuous, and thus, stimulation occurs when the patient will not benefit symptomatically from treatment. This exposes the patient to unnecessary stimulation, which can lead to unnecessary usage of battery, unnecessary exposure to stimulation side-effects, and can possibly contribute to tolerance to DBS therapy. One possible solution is selective stimulation when movement is required. This study will determine signals predictive of motor activity using external sensors such as EMG, and cortical biomarkers of real and imaginary movement that are well-characterized. The primary aim is to demonstrate successful initiation and modulation of DBS therapy using the Activa PC+S system and implanted cortical or thalamic electrodes. Putative improvements in battery usage related to stimulation on-time and definition of coupling signals between thalamus and cortex that characterize tremor state are secondary outcomes.

Official Title
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The Application of DBS Technologies for Demand-driven Management of Essential Tremor

Conditions
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Essential Tremor

Intervention / Treatment
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* Device: Activa PC+S


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Appropriate candidates for DBS with essential tremor Exclusion Criteria: Not meeting inclusion criteria based on tremor amplitude, neuropsychological testing, etc. Prior trauma to the brain on side of putative implantation of stimulator

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: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Activa PC+S<br>Patients will be implanted with standard DBS electrodes for treatment of essential tremor, at the Vim nucleus of the thalamus, and an additional subdural electrode array overlying hand motor cortex.. The patient will receive standard of care programming for thalamic stimulation for essential tremor. During research study visits, implementation and evaluation of closed-loop DBS using the PC+S system will be performed. | Device: Activa PC+S<br>* Implementation of closed loop DBS for essential tremor<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with adverse events | Adverse events will be tracked using CTCAE terminology. | 18 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Battery usage using demand-driven strategies for tremor control | Battery usage will be measured as stimulation on-time and voltage over time using demand-driven stimulation paradigms versus continuous stimulation paradigm. | 18 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Essential tremor; closed-loop DBS