Deep Brain Stimulation for Voice Tremor: Left, Right, or Both Hemispheres?

Study Overview
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Brief Summary
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Deep Brain Stimulation (DBS) is the gold standard treatment for Essential Tremor (ET). ET is a movement disorder which causes the arms, feet, fingers, head or voice to involuntarily shake. The DBS surgical procedure involves implanting an electrode deep within the brain which blocks damaging signals that cause the tremor. Essential Voice Tremor (EVT) is the vocal manifestation of ET and a number of individuals have both ET and EVT, and when these patients are implanted for their ET, their EVT symptoms are often also mitigated. This study aims to quantify the effects of DBS on EVT by testing on these ET+EVT patients. In addition to this, we hope to determine which hemisphere of the brain is responsible for larynx control: left or right.

Detailed Description
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Essential Tremor (ET) is the most common movement disorder in adults, affecting approximately 5% of individuals over the age of 65. Of this 5%, roughly 20% of these patients suffer from Essential Voice Tremor (EVT): the phonatory manifestation of ET. Patients with EVT lose their ability to speak due to a tremor in the muscles of the larynx, pharynx, palate, and tongue. Because of this, an individual's quality of life is limited because they can no longer communicate effectively. The purpose of this study is to quantify to what degree Deep Brain Stimulation improves Essential Voice Tremor. In addition to this, we hope to examine which brain hemisphere is responsible for these positive results: right, left, or both, in a prospective, randomized, double-blinded manner. By finding out more about the subcortical control underpinning speech, we will be able to improve our treatments and understanding of EVT and other neurological speech disorders.

Official Title
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Left, Right, or Bilateral Thalamic Deep Brain Stimulation for Voice Tremor: A Prospective, Randomized, Double-Blinded Trial

Conditions
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Essential Voice Tremor, Deep Brain Stimulation, Essential Tremor, Laryngeal Diseases, Action Tremor, Tremor, Nerve

Intervention / Treatment
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* Device: Deep Brain Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Participant has been implanted with the DBS for ET Participant has significant voice tremor as determined by our laryngology/speech-language pathology team Exclusion Criteria: Participant does not have history of aphasia or other speech/language deficits Participant does not have history of stroke or multiple sclerosis

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: Single Group Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Bilateral Thalamic Vim OFF<br>Participants with bilateral thalamic DBS will be tested four times over 90 minutes. The four tests will include the following in a randomized, double-blinded order: First test: both stimulators on for 15 minutes Second test: left stimulator off, right stimulator on for 15 minutes Third test: left stimulator on, right stimulator off for 15 minutes Fourth test: both stimulators off for 15 minutes In between switching to each test, there will be a 5 minute washout period. | Device: Deep Brain Stimulation<br>* DBS System Medtronic DBS programming settings will be set to maximally alleviate limb tremor, primary reason for referral These settings will be used to evaluate effects of voice tremor as well<br>* Other names: DBS;|
| Experimental: Left Thalamic Vim ON<br>Participants with bilateral thalamic DBS will be tested four times over 90 minutes. The four tests will include the following in a randomized, double-blinded order: First test: both stimulators on for 15 minutes Second test: left stimulator off, right stimulator on for 15 minutes Third test: left stimulator on, right stimulator off for 15 minutes Fourth test: both stimulators off for 15 minutes In between switching to each test, there will be a 5 minute washout period. | Device: Deep Brain Stimulation<br>* DBS System Medtronic DBS programming settings will be set to maximally alleviate limb tremor, primary reason for referral These settings will be used to evaluate effects of voice tremor as well<br>* Other names: DBS;|
| Experimental: Right Thalamic Vim ON<br>Participants with bilateral thalamic DBS will be tested four times over 90 minutes. The four tests will include the following in a randomized, double-blinded order: First test: both stimulators on for 15 minutes Second test: left stimulator off, right stimulator on for 15 minutes Third test: left stimulator on, right stimulator off for 15 minutes Fourth test: both stimulators off for 15 minutes In between switching to each test, there will be a 5 minute washout period. | Device: Deep Brain Stimulation<br>* DBS System Medtronic DBS programming settings will be set to maximally alleviate limb tremor, primary reason for referral These settings will be used to evaluate effects of voice tremor as well<br>* Other names: DBS;|
| Experimental: Bilateral Thalamic Vim ON<br>Participants with bilateral thalamic DBS will be tested four times over 90 minutes. The four tests will include the following in a randomized, double-blinded order: First test: both stimulators on for 15 minutes Second test: left stimulator off, right stimulator on for 15 minutes Third test: left stimulator on, right stimulator off for 15 minutes Fourth test: both stimulators off for 15 minutes In between switching to each test, there will be a 5 minute washout period. | Device: Deep Brain Stimulation<br>* DBS System Medtronic DBS programming settings will be set to maximally alleviate limb tremor, primary reason for referral These settings will be used to evaluate effects of voice tremor as well<br>* Other names: DBS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) | Patients will be asked to read a voice protocol designed to elicit voice tremor symptoms. This will be conducted at the end of every trial arm with a patient sitting in a rest position without moving upper or lower limbs. | At the end of each trial period, typically 15 minutes after change in stimulation settings | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Voice Tremor Severity | At the end of the study, the kinetics of voice tremor and limb tremor will be analyzed to determine if there are any similarities or differences in the time course to deterioration | Measured every 3 minutes for 15 minutes | 

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