Essential Tremor

Background and Rationale Essential tremor (ET) affects over 6 million Americans and approximately 5% of adults over age 60. Patients with ET have a 10-20 times higher risk of developing Parkinson's disease (PD) compared to age-matched populations, with approximately 1% converting to PD annually. Post-mortem studies reveal Lewy body pathology in some ET patients, suggesting a subset may have prodromal PD. Current diagnostic tools (DaTscan, SYNTap) are either insufficiently sensitive for early disease, too expensive, or too invasive for routine screening. The Syn-One Test offers a minimally invasive approach to detect phosphorylated α-synuclein (P-SYN) pathology in skin biopsies. Primary Objectives 1. Identify which ET patients have P-SYN pathology indicative of prodromal PD 2. Predict which patients are most likely to phenoconvert to PD

The objective of this study is to compile real-world outcomes of Boston Scientific commercially approved radiofrequency (RF) ablation systems used in the central nervous system (CNS) for use in functional neurosurgery.

To compile characteristics of real-world outcomes for Boston Scientific Corporation's commercially approved Deep Brain Stimulation (DBS) Systems, when used according to the applicable Directions for Use, for the treatment of Essential Tremor.

Background: \- Deep brain stimulation (DBS) is an approved surgery for certain movement disorders, like Parkinson's disease, that do not respond well to other treatments. DBS uses a battery-powered device called a neurostimulator (like a pacemaker) that is placed under the skin in the chest. It is used to stimulate the areas of the brain that affect movement. Stimulating these areas helps to block the nerve signals that cause abnormal movements. Researchers also want to record the brain function of people with movement disorders during the surgery. Objectives: * To study how DBS surgery affects Parkinson s disease, dystonia, and tremor. * To obtain information on brain and nerve cell function during DBS surgery. Eligibility: \- People at least 18 years of age who have movement disorders, like Parkinson's disease, essential tremor, and dystonia. Design: * Researchers will screen patients with physical and neurological exams to decide whether they can have the surgery. Patients will also have a medical history, blood tests, imaging studies, and other tests. Before the surgery, participants will practice movement and memory tests. * During surgery, the stimulator will be placed to provide the right amount of stimulation for the brain. Patients will perform the movement and memory tests that they practiced earlier. * After surgery, participants will recover in the hospital. They will have a followup visit within 4 weeks to turn on and adjust the stimulator. The stimulator has to be programmed and adjusted over weeks to months to find the best settings. * Participants will return for followup visits at 1, 2, and 3 months after surgery. Researchers will test their movement, memory, and general quality of life. Each visit will last about 2 hours.

The purpose of this research is to determine if the electrophysiologic data collected from standard-of-care microelectrode recordings during human deep brain stimulation (DBS) surgery will be the same using the MAVEN device compared with the standard Alpha Omega device with either a tungsten standard-of-care microelectrode (for microelectrode recordings), or a carbon-fiber microelectrode (for neurotransmitter recordings). The number of microelectrodes used for both the tungsten and the carbon-fiber version will be the same as the standard-of-care.

The primary objective of this study is to characterize real-world clinical outcomes of Deep Brain Stimulation (DBS) using retrospective review of de-identified patient records.

The goal of this clinical study is to compare ulixacaltamide and placebo treatment in essential tremor. The main question it aims to answer is: • Is ulixacaltamide a safe and efficacious treatment for patients with essential tremor? Participants will be asked to participate in one of two clinical studies where they will be treated with either ulixacaltamide or placebo for a period of up to 12 weeks. After the controlled study completion, they will be eligible to participate in a long-term, open-label safety study (LTSS) and be treated with ulixacaltamide. Participants are eligible to enroll directly into the LTSS if they previously participated in an essential tremor trial, received sponsor invitation after being deemed ineligible for the controlled study, or following enrollment closure of the controlled study.

The purpose of this research is to learn more about how the brain works in people with essential tremor, and how it changes after treatment with High-Intensity Focused Ultrasound (HiFU). Essential tremor is a movement disorder that causes shaking, usually in the hands, and can make everyday tasks difficult. HiFU is a treatment that uses focused sound waves to target a small area in the brain involved in tremor. In this study, the investigators aim to understand how this treatment affects the brain's networks by using safe, non-invasive tests such as brain imaging, brain wave recordings, and movement assessments.

The brain networks controlling movement are complex, involving multiple areas of the brain. Some neurological disorders, like Parkinson's disease (PD) and essential tremor (ET), cause abnormalities in these brain networks. Deep brain stimulation is a treatment that is used to treat these types of neurological diseases and is thought to help patients by modulating brain networks responsible for movement. Levodopa medication is also used to modulate this brain networks in patients with PD. The overall objective is to develop a unified theory of basal ganglia thalamocortical (BGTC) circuit dynamics that accounts for disease symptomatology, movement, and their inter-relationship. The underlying hypothesis, is that the rigidity and bradykinesia of PD are fundamentally related to excessive functional coupling across nodes in the BGTC motor circuit impeding effective information flow. In this research, the investigator will take advantage of the unique opportunity provided by awake deep brain stimulation surgery to learn more about how the brain functions in a diseased state and how deep brain stimulation changes these networks to make movement more normal. The investigator will simultaneously assess cortical and subcortical electrophysiology in relation to clinical symptoms and behavioral measures and in response to deep brain stimulation, cortical stimulation, and pharmacologic therapy in patients undergoing Deep Brain Stimulation (DBS) implantation surgery.

The purpose of this study is to elucidate the structural connectivity of the dentato-rubro-thalamic tract (DRTt) and to detect functional network changes due to DRTt stimulation

The purpose of this study is to determine the changes in quality of life and degree of tremor for patients with essential tremor or Parkinsonian tremor who are treated by stereotactic radiosurgery (SRS). This is a questionnaire-based study. Please see Detailed Description below for more information.

Deep brain stimulation (DBS) has become a gold-standard symptomatic treatment option for Parkinson's disease (PD) and is also explored for a variety of other neurological disorders. The implantation of electrodes into deep brain areas has not only enabled the application of electrical stimuli, but has also provided researchers and clinicians with an unprecedented window to investigate aberrant neuronal activity right at the core of pathological brain circuits. Local field potentials (LFP) have already been readily investigated through externalised DBS electrode wires prior to internalisation and connection to an implantable neurostimulator. In the case of PD, motor symptoms have been evidenced to correlate with exaggerated beta oscillatory activity (13-35 Hz) in the LFP recorded from the subthalamic nucleus (STN). Firstly, beta activity recorded in the STN at rest in patients withdrawn from their medication has been correlated with the Unified Parkinson's Disease Rating Scale (UPDRS) across patients. Secondly, a reduction of signal power in the beta-band was correlated with clinical improvements of motor symptoms. Thirdly, the two main therapeutic strategies, the administration of L-Dopa, and high-frequency DBS both lead to a suppression of beta-synchronicity in the STN. Furthermore, beta-oscillations show fast and movement-dependent modulation over time and can serve as a biomarker and feedback signal to control the delivery of DBS. The investigators recently implemented deep brain electrical neurofeedback to provide real-time visual neurofeedback of pathological STN oscillations through externalised DBS electrodes and showed that PD patients were able to volitionally control and reduce subthalamic activity within a single 1 hour session. Moreover, neurofeedback-learnt strategies accelerated movements and could be retained in the short- and mid-term. Only recently, a newly developed neurostimulator, the Percept™ PC (Medtronic Neurological Division, Minneapolis, MN, USA), has been clinically approved, which can not only apply electrical impulses, but also enable the measurement and transmission of brain activity. This neurostimulator is now the first choice for implantations at the University Hospital Zurich and is used for a variety of neurological disorders. The investigators' goal is to investigate whether neurofeedback through a fully implanted deep brain stimulation device is possible and can lead to a better control of pathological oscillations as well as symptom mitigation. Having shown that endogenous control over deep brain oscillations is possible, the investigators will also test this novel therapeutic approach for pathologies other than PD that are also treated with DBS. Neurofeedback using implanted DBS electrodes will have the advantage of enabling longer and multiple-day training sessions, which the investigators hypothesise to have a larger impact on control over pathological deep brain oscillations and neurological symptoms, as such a fully implanted neurofeedback system no longer requires the externalisation of DBS wires and is as such no longer limited to the first two days after electrode implantation. All in all, the investigators will not exceed a total streaming time of 7 hours per patients (7 d of battery time), which the investigators deem justifiable with respect to a battery life of \> 5 years. This proposed research is highly significant as it will help our understanding of various neurological diseases that are highly prevalent in society (PD being, for instance, the second most common neurodegenerative disorder after Alzheimer's disease) and might culminate in novel, endogenous treatment strategies. The overall risk for patients is minimal to non-existent, as stimulation parameters are unaffected and the intended changes in brain activity are self-induced while DBS stimulation is off.

The currently available treatments of Parkinson's disease (PD) and Essential Tremor (ET) are inadequate and accompanied by adverse side effects making the treatment much less effective. This includes treatments with pharmaceuticals as well as electrical brain stimulation (DBS; Deep Brain Stimulation). To address this challenge, we have systematically worked to identify and overcome the shortcomings with current brain stimulation. Essential has been to achieve an understanding of the mechanisms behind the ubiquitous tissue reactions (often referred to as "foreign body reactions"), with loss of nerve cells near implanted electrodes and how to accomplish minimal tissue reactions/damage, which is necessary to enable therapeutically efficient low-intensity stimulation at precise locations. A further challenge relates to individual differences at the level of neuronal networks, making the exact sites in the brain that cause therapeutic and adverse side effects when stimulated not known in advance and thus requiring individual determination. Our strategy has therefore been to develop highly biocompatible microelectrodes (thinner than a human hair and highly flexible) and a guiding investigational device for controlled insertion of a cluster of such microelectrodes in deep target tissue. This enables individualized selection of appropriate stimulation sites. This technique, termed by us "High Definition Brain Stimulation" (HDBS), proved remarkably successful in animal models of both Parkinson's disease and pain by reliably providing powerful symptom relief without noticeable adverse side effects. For this first in human (FIH) investigation of microelectrode-based brain stimulation, we have systematically minimized all identified and foreseeable risks through optimization of the microelectrodes, the design of the investigational device for HDBS and development of simple minimally invasive surgical insertion methods. Extensive monitored safety tests in animals have confirmed the picture of negligeable tissue reactions/damage and absence of bleeding in the target area. Biological safety is also ensured by using only well-established materials documented for chronic implantation in the brain, established sterilization methods, identified safe stimulation intensities, and that the insertion procedures are adapted to well-established precision neurosurgical instruments and routines. The study is an early (FIH) feasibility clinical investigation which will be conducted in up to 12 patients with Parkinson's disease and/or Essential Tremor who are already scheduled for implantation of established DBS. The HDBS device will be inserted into awake patients in the same track as planned for the established DBS electrode. The evaluation will follow a protocol that includes stimulation of predetermined subsets of microelectrodes at up to 4 predetermined levels (depth) in the brain. The stimulation intensity for each subgroup is gradually increased until either a therapeutic effect or an undesirable side effect has been achieved. If an unacceptable effect is elicited, stimulation is immediately interrupted and a new subset of electrodes will be tested. After completion of the evaluation, the HDBS cluster electrode is removed and the implantation of an established permanent DBS electrode is completed. The evaluation will take up to 2.5 hours per patient. The patient's verbal responses, gestures, changes (if any) in tremors, rigidity, speech ability (such as slurring) or facial expressions before, during and after stimulation will be linked to the stimulation parameters (stimulation intensity, subgroup of microelectrodes, depth in the brain and time of reaction) and documented in writing and through video recordings. The analysis will only be made on anonymized data. The primary objective of this early feasibility, FIH, clinical investigation is to clarify whether HDBS (High Definition Brain Stimulation), through individualized stimulation of appropriate subgroups of implanted biocompatible microelectrodes, can provide a powerful therapeutic effect with minimal negative side effects also in humans. In addition, it is intended to simultaneously obtain important information that can be used by the neurosurgeon to improve the subsequent placement of the already scheduled permanent DBS electrode in the individual patient and thereby improve the treatment. Consequently, the secondary objective is to clarify whether HDBS can be used by the neurosurgeon to improve the placement of a permanent DBS electrode. The project paves the way for permanent HDBS with completely new opportunities for powerful, sustainable therapy with minimal side-effects in Parkinson's disease, Essential Tremor and other intractable neurologic disorders. Moreover, the HDBS technology enables new and potent opportunities for brain research.

The investigators propose to advance Vim-FUSA (Ventral Intermediate Nucleus - Focused Ultrasound Ablation) with the support of 3-D tractography, a neuroimaging technique to visually represent nerve tracts within the brain. The investigators hypothesize that 3-D tractography Vim-FUSA will improve the Vim ablation compared to standard Vim-FUSA and prove safe and feasible in the clinical setting. The investigators also hypothesize that intraoperative magnetic resonance (i-MR) monitoring will differentiate ablated tissue from immediate perilesional edema and accurately predict the Vim-FUSA clinical outcomes.

This is a post-market (Phase IV) randomized, controlled, blinded, multicenter study with the aim to determine the added value of staged bilateral Exablate thalamotomy compared to a group of patients on previous unilateral treatment combined with local standard medical treatment.

The NIH grant has funded the development of a physiological brain atlas registry that will allow us to significantly improve the data collectioin and use of physiological data into a normalized brain volume. This initially was used to improve DBS implants for Parkinson's Disease, Dystonia, Essential Tremor, and OCD, but now includes data acquired during all stereotactic brain procedures.

This is a prospective, single-center, single-arm, open-label clinical study designed to evaluate the long-term efficacy and safety of non-invasive neuromodulation using transcutaneous afferent patterned stimulation (TAPS) in patients with essential tremor (ET). Essential tremor is a common movement disorder that can significantly impair daily functioning and quality of life. Pharmacological treatments are often limited by suboptimal efficacy or adverse effects, highlighting the need for alternative therapeutic approaches. In this study, eligible participants with essential tremor will receive TAPS treatment over a defined follow-up period. Clinical outcomes, including tremor severity, functional performance, and patient-reported outcomes, will be assessed longitudinally to evaluate treatment effectiveness. Safety will be monitored throughout the study by recording adverse events and device-related complications. The results of this study aim to provide clinical evidence regarding the long-term therapeutic potential and safety profile of TAPS as a non-invasive neuromodulation strategy for essential tremor.

Low intensity focused ultrasound (LIFUS) has the potential to be used as a means of non-invasive neuro-modulation. To this day, the use of LIFUS is under investigation. Studies in healthy subjects have shown that application of LIFUS to the motor region of the brain can mildly decrease neuron excitability in healthy controls. The purpose of the present study is to evaluate the effects of LIFUS on brain tissue excitability in patients with movement disorders in order to elucidate the therapeutic potential of LIFUS.

The objective of this study is to compare the effects of image-guided programming algorithm using various image segmentations vs standard clinical programming on reduction of tremor and patient satisfaction.

Deep brain stimulation (DBS) of the thalamus is an effective treatment for medically refractory essential tremor (ET). DBS involves delivering continuous stimulation to the brain through electrodes permanently implanted in the thalamus. Despite proven effectiveness, the long-term benefit of DBS can wane over time (habituation) and side effects, including paresthesia and dysarthria, often limit the amplitude of the stimulation, resulting in suboptimal control of tremor. In clinical practice, many groups advise patients to switch their devices off at night to avoid habituation and reduce side effects. However, manually turning off the device at night can result in uncontrolled tremor when the patient moves at night. This study aims to develop an algorithm that automatically turns off stimulation when a patient is asleep, based on circadian brain signals. Turning off stimulation could potentially improve the therapy by limiting adverse effects, increasing efficacy, reducing the risk of habituation, and prolonging battery life. This study will evaluate the feasibility, safety, and tolerability of circadian adaptive DBS.

This is a research study to determine how COBENFY KarXT (FDA approved), a drug which has been approved for treatment of certain disorders, affects brain activity and cognitive tasks which may be regulated by the cholinergic system. This study aims to answer: 1) how cholinergic circuitries act during task performance in humans, and 2) develop a better understanding of how cognitive control interacts with learning, memory and decision making in the setting of cholinergic manipulation. Participants will complete a single treatment arm, regardless of which surgical procedure they are to receive. An anesthesiologist or other clinical staff will administer either the drug or the saline at a critical point which addresses the research questions, prior to patient surgery. This will be either with the drug, or the placebo pill. Half of the participants will be randomized to receive the drug, and the other half of these the placebo. Participants will be unaware whether the actual drug has been received. Essential tremor patients who participate will complete a cognitive task during an awake surgery. Epilepsy patients who participate will have a resting state recording during the procedure from the deep cortical layers of the brain. A probe will be used during the surgery to measure the effects of this drug and other procedures of the study on the cholinergic system. This probe is the clinical probe known as the AlphaOmega, which is FDA approved for standard of care procedures. Researchers will compare the brain activity between treatment arms to determine what brain activity changes based on the cholinergic manipulation.

This objective of this study is to document the safety and feasibility of electrical stimulation of the deep cerebellar nuclei for refractory tremor using the Medtronic Percept RC Deep Brain Stimulation System. The population will consist of patients that have either failed a prior intervention (Vim DBS or HIFU thalamotomy) or determined to not be suitable candidates for Vim DBS or HIFU thalamotomy because they have a cerebellar outflow or MS-related tremor. Those patients with a previous intervention, must have a prior diagnosis of ET, cerebellar outflow tremor, or MS-related tremor. Subjects without a previous intervention must have a diagnosis of cerebellar outflow tremor or MS-related tremor.

Deep brain stimulation (DBS) is a surgical procedure for the treatment of Essential Tremor (ET). A novel approach to current DBS approaches is called coordinated reset DBS (CR-DBS) which uses different patterns of stimulation at lower currents and can address the limitations of traditional DBS that uses continuous high amplitude, high frequency stimulation. This study will evaluate the feasibility, safety and short-term efficacy of thalamic CR-DBS in upper extremity ET. The goal of this study is to evaluate the safety and short-term efficacy of thalamic CR- DBS in ET, including the acute (during CR-DBS) and carryover (following DBS cessation) effects, and compare these to those induced by clinically optimized T-DBS. To achieve our goal, a low-risk, two-phase clinical study will be conducted in patients with upper extremity (UE) ET. The first aim is to identify the spatial location and peak frequency of tremor related oscillatory activities in VIM (Phase I). The second aim is to compare the acute effects of thalamic CR-DBS to clinically optimized T-DBS (Phase II).

This open-label pilot study will evaluate the safety, tolerability, feasibility, and preliminary efficacy of repeated low-intensity focused ultrasound pulsation (LIFUP) targeting the ventral intermediate nucleus (Vim) of the thalamus in patients with Essential Tremor (ET). Twelve adults with clinically diagnosed ET will undergo six LIFUP treatment sessions over approximately two weeks using the BrainSonix BX Pulsar 1002 system. Tremor severity will be assessed using clinician-rated scales (TETRAS and FTM), patient-reported quality-of-life measures (QUEST), and objective accelerometry before and after treatment sessions, with additional follow-up visits at one and three months post-treatment. MRI scans will be performed at baseline and after the final treatment session to monitor safety. The study aims to characterize whether non-ablative focused ultrasound can safely and transiently modulate tremor-related thalamic circuits and provide preliminary evidence supporting future controlled trials of LIFUP for ET.

The purpose of this study is to collect electrophysiological data related to functional brain network changes in patients undergoing deep brain stimulation for the treatment of essential tremor. Participants will either 1) have electroencephalography (EEG) scalp electrodes placed, or 2) remain seated with their head inside of a magnetoencephalography (MEG) recording system, as resting-state and task-related data are acquired. Spontaneous electrophysiological activity will be recorded in both the eyes open and eyes closed conditions with the participant seated comfortably. These recordings will be repeated in the DBS OFF and DBS ON states, with the ON state involving specific settings identified as optimal, sub-optimal, or ineffective at achieving tremor control. They will also be repeated following the optional administration non-DBS tremor mitigation techniques, which may include one or more of the following: 1) cooling the limb, 2) oral administration of alprazolam, 3) oral consumption of ethanol (alcohol), or 4) peripheral nerve stimulation.