Deep Brain Stimulation for Laryngeal Dystonia: From Mechanism to Optimal Application

Study Overview
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Brief Summary
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Deep Brain Stimulation (DBS) is a neurosurgical procedure used to treat tremors, and dystonia. This study will enroll people who have a form of focal dystonia that affects their vocal cords called Adductor Laryngeal dystonia (ADLD). Participants will undergo Deep Brain Stimulation surgery to treat laryngeal dystonia as part of their clinical care. Before surgery, as part of the study they will have specialized testing to study the movement of the vocal cords, as well as functional magnetic resonance imaging (fMRI). While in the operating room, researchers will examine brain waves to better understand how faulty brain firing patterns lead to dystonia. After surgery, and activation of the deep brain stimulator, participants will repeat speech testing and vocal cord imaging as well as magnetic resonance imaging (MRI).

Official Title
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Deep Brain Stimulation for Laryngeal Dystonia: From Mechanism to Optimal Application

Conditions
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Laryngeal Dystonia, Adductor Spastic Dysphonia of Dystonia

Intervention / Treatment
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* Device: Deep Brain Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with ADLD and ADLD plus tremor, as diagnosed by routine clinical examination by laryngologist, speech language pathologist, and neurologist. Patients undergoing globus pallidus interna (GPi) deep brain stimulation (DBS) for ADLD with tremor Age range of 18-80 years Native speakers of American English will be recruited since there are known differences in voice and neural signals of native and non-native speakers No evidence for dementia as assessed by neurologist. No evidence for severe untreated mood disorder as assessed by neurologist, or as evident on self-report (Beck Depression Inventory-II score > 29, Beck Anxiety Inventory Score > 26. At least 3 months since last botulinum toxin injection and the patients would need to be fully symptomatic with no residual effects of botulinum toxin on voice quality. Exclusion Criteria: Individuals younger than 18 years and older than 80 years of age. Women who plan to become pregnant during the study period or are currently breastfeeding. Prior history of stroke, brain surgery, or other neurological disorder besides the one under study. Prior laryngeal framework surgeries or other disorders affecting the vocal folds Patients who are asymptomatic due to treatment with botulinum toxin into the vocal folds. Presence of ferromagnetic implants and cardiac implants that would be contraindicated to MRI Gagging or discomfort that would preclude the placement of the endoscope to visualize the larynx Dementia, severe depression or severe anxiety. Any clinical condition or medication judged by the investigators to potentially preclude the patient from safely completing awake brain surgery and research protocols.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Deep Brain Stimulation<br>Voice outcomes and Magnetic resonance imaging will be compared pre- and post-DBS (Deep brain stimulation) in patients with laryngeal dystonia and adductor laryngeal dystonia. The evaluators will be masked for analyzing the voice outcomes pre-and post-DBS | Device: Deep Brain Stimulation<br>* Deep Brain Stimulation of Globus Pallidus interna<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in total number of Vocal fold movements | Vocal fold movements will be quantified (vibratory breaks + micromotions+ aperiodicities) using high-speed videoendoscopy (HSV) on sustained phonation of the vowel, words, and sentence production. The videoendoscopic recording will be obtained | Before surgery, within 24 hours after surgery, 6 -9 months after surgery | 
| Change in Acoustic voice recordings | Acoustic voice recordings will be obtained using a microphone. Acoustic measurement of voice (voicing percentage) will be obtained from sustained phonation of the vowel /a/, sentences and reading a paragraph. | Before surgery, within 24 hours after surgery, 6-9 months after surgery | 
| Microelectrode recording | Microelectrode recording is performed routinely during DBS (Deep brain stimulation) surgery. The study procedure will be to record voice simultaneously on sustained phonation of the vowels, syllables, and sentences using the data acquisition system NI USM 6221 with a microphone and high-speed videoendoscopy. Beta and theta band power spectral density will be analyzed as measurements. | during surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Neuropsychological testing: Trails A | Neuropsychological testing will be obtained pre (standard of care for DBS surgery) and 6 months post DBS surgery (experimental) to evaluate psychomotor speed | Before surgery, and 6-9 months after surgery | 
| Change in Neuropsychological testin: Trails B | Neuropsychological testing will be obtained pre (standard of care for DBS surgery) and 6 months post DBS surgery (experimental) to evaluate mental flexibility | Before surgery, and 6-9 months after surgery | 
| Change in Neuropsychological testing: Controlled Oral Word Association Animal fluency | Neuropsychological testing will be obtained pre (standard of care for DBS surgery) and 6-9 months post DBS surgery (experimental) to evaluate verbal fluency | Before surgery, and 6-9 months after surgery | 
| Change in Resting state Functional Magnetic Resonance Imaging (fMRI) | Resting state Functional Magnetic Resonance Imaging (rs-FMRI) | before surgery and 6-9 months after surgery | 
| Change in Voice Handicap Index | A 30-point questionnaire to describe the voice and the effects of voice on their daily lives. The scores range from 0 to 120. 0 to 30 is a low score with minimal handicap and 61 to 120 is considered severe handicap, 31 to 60 moderate handicap | before surgery and 6-9 months after surgery | 
| Change in Speech Intelligibility | will be computed from the 2nd, 3rd, and 4th sentences of the Rainbow passage as the number of correct words identified. | before surgery and 6-9 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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deep brain stimulation