Deep Brain Stimulation Effects in Dystonia

Study Overview
=================
Brief Summary
-----------------
Deep Brain Stimulation (DBS) is an effective therapy for patients with medically refractory primary dystonia. However, DBS programming for dystonia is not standardized and multiple clinic visits are frequently required to adequately control symptoms. We aim to longitudinally record brain signals from patients using a novel neurostimulator that can record brain signals. We will correlate brain signals to clinical severity scores to identify pathological rhythms in the absence of DBS, and we will study the effects of DBS on these signals in order to guide clinical programming. We are going to recruit patients who receive the Medtronic Percept device, which allows for brain signal recordings (this feature is FDA approved). The investigators will be conducting an observational study using this device to collect data that the subjects receive as standard of care.

Detailed Description
-----------------
The development of newer technologies has allowed clinicians and researchers to better understand pathophysiological underpinnings of different disorders managed with neuromodulation. There is a paucity of information, however, on dystonia, likely due to its rarity of cases and variability in phenomenology to allow generalization of findings. Possible abnormal brain signals, such as high activity in theta band (defined as rhythms in the 4-12Hz range ), have been proposed by small case series. The development of newer technologies has allowed clinicians and researchers to better understand pathophysiological underpinnings of different disorders managed with neuromodulation. There is a paucity of information, however, on dystonia, likely due to its rarity of cases and variability in phenomenology to allow generalization of findings. Possible abnormal brain signals, such as high activity in theta band (defined as rhythms in the 4-12Hz range ), have been proposed by small case series

Official Title
-----------------
Deep Brain Stimulation Effects in Dystonia: Time Course of Electrophysiological Changes in Treatment

Conditions
-----------------
Dystonia

Intervention / Treatment
-----------------
* Device: Deep brain stimulation (DBS)


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patient gives an informed consent. Patient is over 18 years of age. Having a diagnosis of a primary dystonia confirmed by a trained movement disorders neurologist; Having failed or not tolerated conventional medical management, at the discretion of the neurologist managing the patient; Exclusion Criteria: Having alternative diagnoses to a primary dystonic syndrome; Having comorbid neurodegenerative disorders that may affect mobility or cognition (e.g. comorbid Parkinson's disease); Having sequelae of prior brain insult (e.g. prior stroke or brain tumor); History of prior resectivebrain surgery (e.g. tumor resection); Not being a DBS candidate; Selection of alternative targets to conventional GPi; Receiving unilateral implants Having a higher surgical risk that precludes patient from having standard intraoperative mapping.

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with dystonia<br>Patients with dystonia who have clinically been deemed candidates for DBS surgery. | Device: Deep brain stimulation (DBS)<br>* Deep brain stimulation is an FDA approved therapy that involves surgical implantation of electrodes in deep brain targets and an implantable pulse generator delivers electrical pulses.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Unified Dystonia Rating Scale (UDRS) | A clinical scale fo dystonia severity (0-4, 0:no symptoms, 4:extreme) | 12 months | 
| Burke-Fahn-Marsden Dystonia Rating Scale | A clinical scale fo dystonia severity (0-4, 0:no symptoms, 4:extreme) | 12 months | 
| Toronto Western Spasmodic Torticollis Rating Scale | A clinical scale of dystonia severity (0-4, 0:no symptoms, 4:extreme) | 12 months |