Clinical Research Directory

Motor Network Physiology

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.

Clinical and Physiological Studies of Tremor Syndromes

Background: Researchers have some data on how the brain controls movement and why some people have tremor. But the causes of tremor are not fully known. Researchers want to study people with tremor to learn about changes in the brain and possible causes of tremor. Objective: To better understand how the brain controls movement, learn more about tremor, and train movement disorder specialists. Eligibility: People ages 18 and older with a diagnosed tremor syndrome Healthy volunteers ages 18 and older Design: Participants will be screened with: * Medical history * Physical exam * Urine tests * Clinical rating scales * Health questions * They may have electromyography (EMG) or accelerometry. Sensors or electrodes taped to the skin measure movement. Participation lasts up to 1 year. Some participants will have a visit to examine their tremor more. They may have rating scales, EMG, and drawing and writing tests. Participants will be in 1 or more substudies. These will require up to 7 visits. Visits could include the following: * EMG with accelerometry * Small electrodes taped on the body give small electric shocks that stimulate nerves. * MRI: Participants lie on a table that slides into a cylinder that takes pictures of the body while they do simple tasks. * Small electrodes on the scalp record brain waves. * A cone with detectors on the head measures brain activity while participants do tasks. * A wire coil held on the scalp gives an electrical current that affects brain activity. * Tests for thinking, memory, smell, hearing, or vision * Electrodes on the head give a weak electrical current that affects brain activity. * Photographs or videos of movement Participant data may be shared with other researchers.

Deep Brain Stimulation Surgery for Movement Disorders

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.

Essential 3 - Decentralized, Phase 3 Study Evaluating the Safety and Efficacy of Ulixacaltamide in Essential Tremor (ET)

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.

Sensory-specific Peripheral Stimulation for Tremor Management

The purpose of this study is to understand the neurophysiological mechanisms of peripheral electrical stimulation (PES) in modulating supraspinal tremorogenic input to motoneurons. For this purpose, the investigators will use transcutaneous PES, high-density electromyography (HD-EMG), transcranial magnetic stimulation (TMS), electroencephalography (EEG), magnetic resonance imaging (MRI), and neuromusculoskeletal modelling. This study will be carried out in both healthy participants and patients with essential tremor (ET) and Parkinson's disease (PD).

Impact of Sensory Electrical Stimulation on Sensation and Tremor

The purpose of this study is to understand the acute, short-term and long-term impact of transcutaneous and/or percutaneous electrical stimulation with afferent-specific electrical stimulation (asES) on proprioception and fine motor control in the upper extremity. For this purpose, the researchers will use transcutaneous and/or percutaneous asES, high-density electromyography (HD-EMG), arm kinematic measurements, and standardized clinical assessments. This study will be conducted in healthy able-bodied individuals and patients with essential tremor (ET).

EMBRACE Tremor BiFUS

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.

Deep Brain Stimulation (DBS) Retrospective Outcomes Study

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.

Deep Brain Stimulation of the Deep Cerebellar Nuclei for Refractory Tremor

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.

Assessment of the Safety and Efficacy of the Felix NeuroAI Wristband in Essential Tremor

The goal of this clinical study is to compare Felix NeuroAI Wristband and sham device in patients with essential tremor. The main question it aims to answer is: • Is Felix a safe and efficacious treatment for patients with essential tremor? Participants will be treated with either Felix or Sham for a period of up to 90 days. After that, they will be eligible to participate in a long-term, open-label study and be treated with Felix.

Analysis of Cutaneous Phosphorylated Alpha-Synuclein to Identify Patients at Risk of Progressing From Essential Tremor to Parkinson's Disease

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

Boston Scientific Registry of Deep Brain Stimulation for Treatment of Essential Tremor (ET)

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.

Radiofrequency (RF) Ablation Prospective Outcomes Study for Central Nervous System - RAPID for CNS

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.

Pilot Study of the Felix System in Patients With Essential Tremor and Parkinson's Tremor

A prospective, open-label, multi-center pilot study designed to evaluate the safety and effectiveness of the Felix system in the relief of upper limb tremors in adults with essential tremor and Parkinson's disease.

Coordinated Reset Deep Brain Stimulation for Essential 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).

Optimization of VIM Targeting in Essential Tremor Surgery

Deep brain stimulation (DBS) for essential tremor is based on the intermedius ventralis nucleus of the thalamus (VIM) stimulation. This structure is however very difficult to target, as it remains invisible on imaging. The current procedure based on awake surgery with clinical and electrophysiological testings has several limitations that lead us to develop a probabilistic model to locate precisely the target. This study aims to show that asleep DBS surgery based on this new targeting method leads to at least the same clinical results than the classical procedure.

Decision-making and Emotion Recognition in Essential Tremor

The present study aims at investigating cognitive functions requiring orbitofrontal control, namely decision-making and facial emotion recognition. The investigators hypothesize that decision-making and facial emotion recognition are impaired in patients with essential tremor (ET) due to frontal lobe dysfunction which may have consequences in daily social life.

Linac FRACtionated Radiosurgical THALamotomie in Tremors (FRACTHAL)

Radiosurgical thalamotomy on GammaKnife has been shown to be effective in the management of tremors. However, several teams describe a significant risk of severe neurological complications. In addition, fitting the invasive frame and the need to travel to GammKnife centers often limit access to treatment in this population of elderly patients. Linear accelerators have greatly improved their precision, now reaching that of GammaKnife. A possible alternative is therefore to treat patients on linear accelerators, without an invasive frame. The objective of the FRACTHAL study is to assess the feasibility and safety of treatment of essential and / or parkinsonian tremor by fractional radiosurgical thalamotomy on a linear accelerator. The main hypothesis of the FRACTHAL study is based on the fact that dividing the dose into 3 sessions will both protect healthy tissue around the target while maintaining therapeutic efficacy on the treatment target.

The Effect of Alcohol on Common Tremor Syndromes

The aim of this interventional study is to compare the response to alcohol in patients with essential tremor (ET), essential tremor plus (ETplus), dystonic tremor (DT), tremor associated with dystonia (TaD) and tremor in Parkinson´s disease (PD). The main question to be answered is: • Is there a difference in the objective alcohol responsiveness of patients with ET, DT, TaD and PD? Participants will receive either vodka with rum-flavoured orange juice with a target blood alcohol of 0.4 ‰ or a non-alcoholic rum-flavoured orange juice (vice versa on the second study day). Before and 30, 60 an 120 minutes after the study drink the participants will undergo a clinical examination of the tremor and accelerometry will be performed. Researchers will compare alcohol and placebo in a randomized cross over way to see if the effect of alcohol on tremor exceeds the placebo effect.

Functional Brain Network Changes in Patients Undergoing Deep Brain Stimulation for Essential Tremor

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.

Closed-loop TMS for Tremor

This study investigates the potential of phase-locked transcranial magnetic stimulation (TMS) as a non-invasive intervention for tremor in patients with Essential Tremor (ET) and Parkinson's Disease (PD). Tremor is a prevalent symptom that significantly impacts physical function and social participation. ET affects approximately 1% of the global population and worsens with age, while PD tremor is often less responsive to conventional dopaminergic therapy. Current treatments, including oral medications (propranolol, primidone), anticholinergics, and deep brain stimulation (DBS), are either limited by efficacy, side effects, or invasiveness. These challenges highlight the need for alternative, less invasive therapeutic options. The rationale for the study is based on the principle of phase-dependent neural modulation. Just as a swing's amplitude can be increased or decreased depending on when it is pushed, neural oscillations underlying tremor can theoretically be suppressed by precisely timed stimulation. Previous studies have shown that TMS over the motor cortex at tremor frequency (\~5 Hz) produces modest improvements in PD rest tremor. This study aims to enhance these effects by targeting amplitude-suppressing phases in the tremor cycle, potentially leading to greater and cumulative tremor reduction. The study has two components: Study 1 (Primary Objective): Determine whether phase-locked TMS can acutely reduce tremor. Participants (20 ET, 20 PD) will undergo two visits where tremor is recorded via inertial measurement units (IMUs) and surface EMG. TMS will be delivered over the motor cortex at or below active motor threshold, synchronized to the participant's tremor phase. The primary outcome is the change in tremor power during stimulation compared to no stimulation, measured objectively via IMU signals. Study 2 (Secondary Objective): Examine whether stimulation at the maximal tremor-suppressing phase, identified in Study 1, produces a larger reduction in tremor amplitude than stimulation at the minimal suppressing phase or sham stimulation. This will involve three additional sessions per participant, randomized for order, with outcomes assessed via IMU tremor power and participant-reported measures including the Quality of Life in Essential Tremor Questionnaire (QUEST), TETRAS, and Unified Parkinson's Disease Rating Scale (UPDRS). Study Design and Procedures: The design is a within-subject crossover. Participants may withhold tremor medications during visits to reduce confounding effects. EMG electrodes and IMU sensors will record tremor, while a figure-of-eight TMS coil will deliver phase-locked pulses. Phase-specific stimulation trains are applied for 3 seconds at intervals, with randomized order across multiple blocks. Study sessions last under two hours, including setup and post-stimulation recordings. Participants are recruited via self-referral or through DeNDRoN, screened for eligibility, and provide informed consent. Inclusion criteria require symptomatic ET or PD tremor, age ≥18, and ability to consent. Exclusion criteria include epilepsy, psychiatric illness, metal implants, pacemakers, or other conditions contraindicating TMS. Participants may withdraw at any time without penalty. Safety Measures: TMS and IMU recordings are low-risk, with potential minor effects including scalp tapping sensations, muscle twitches, or mild headaches, which are managed through monitoring and coil adjustment. Serious adverse events are defined, and procedures for reporting and auditing are established in accordance with UK regulations and Good Clinical Practice. Data Analysis: Tremor power will be quantified from IMU recordings using spectral analysis. Statistical comparisons between stimulation conditions and baseline will be conducted using paired t-tests or Wilcoxon tests. The study will employ validated software for randomization and analysis (SPSS, Matlab). Data will be pseudo-anonymized, securely stored, and archived for long-term research use. Ethical Considerations: The study follows the Declaration of Helsinki, Good Clinical Practice, and institutional approvals. Participants' privacy and data protection are ensured under GDPR standards. There are no commercial conflicts of interest, and participants are reimbursed for travel expenses. In summary, this research aims to evaluate the efficacy of phase-locked TMS as a non-invasive, targeted interventionfor tremor in ET and PD. By systematically stimulating the motor cortex at tremor-specific phases, the study seeks to establish a foundation for future minimally invasive treatments that could complement or replace existing pharmacological and surgical options.

Attention and Eye Movement in Parkinson's Disease

The goal of this observational and interventional study is to understand how therapeutic deep brain stimulation (DBS) affects attention, perception and cognition in participants with Parkinson's disease (PD) and non-PD movement disorders, including essential tremor (ET) and dystonia (DT). The main questions it aims to answer are: * Does impaired control of attention and eye movement in PD alter how social cues are perceived and interpreted? * Does therapeutic DBS improve or worsen attentional and perceptual deficits for social cues in PD, ET and DT? * Can DBS be optimized to restore normal attentional control in PD while remaining an effective therapy for other aspects of the disorder. * What do parts of the brain targeted by DBS contribute to the control of attention? Using an eye tracking camera, investigators will study how participants with PD, ET and DT look at and perceive facial expressions of emotion before and after starting DBS therapy, in comparison to a group of healthy participants without ET, PD, DT or DBS. Participants with PD, ET and DT will see and rate morphed facial expressions on a computer screen in three conditions: * Before starting DBS therapy (over approximately 1 hour). * In the operating room, during the standard procedure to implant DBS electrodes, while the participant is awake (for no more than 15 minutes). * After starting DBS therapy, with brief experimental changes of DBS stimulation level and frequency (over approximately 1 hour).

Magnetoencephalography (MEG) Pilot 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.

Transcranial Temporal Interference Stimulation (tTIS) To Modulate Essential Tremor

The goal of this proof-of-concept study is to examine the effects of a relatively new, non-invasive electrical current-based technique, transcranial temporal interference stimulation (tTIS), in patients with Essential Tremor (ET). TTIS is delivered via a Digitimer Ltd. stimulator, the "DS5 Isolated Bipolar Constant Current Stimulator." The method enables targeting deep cerebral structures to selectively modulate neurons. The structure of interest in the present study is the ventralis intermedius (VIM) of the thalamus, which plays a key role in tremor generation in people with essential tremor. Therefore, techniques targeting the VIM nucleus can potentially improve the tremor and the quality of life in the long term, as is the case with MRI-guided high-intensity focused ultrasound (MRgHIFU). Despite its efficiency, MRgHIFU can lead to side effects that could benefit from improved predictive modeling. In our proof-of-concept study, the investigators aim to examine whether tTIS of the VIM nucleus can alter tremor characteristics and, therefore, mimic the effects of MRgHIFU. This work would pave the way for future clinical trials to design prediction tools for MRgHIFU if the investigators can demonstrate the positive impact of tTIS.