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57 active trials for Essential Tremor

Pathophysiology of Tremor-modulating Mechanisms of Propranolol and Primidone in Essential Tremor

Pathophysiology of tremor-modulating mechanisms of propranolol and primidone in essential tremor (ET) will be studied using accelerometry with electromyography (EMG), transcranial magnetic stimulation (TMS), and eyeblink conditioning paradigm (EBCC). TMS is a well-established experimental method for studying the effects of drugs on motor cortex excitability. EBCC is a learning paradigm that can be used for studying cerebellar dysfunction since only brainstem and cerebellar functions seem to be needed for this paradigm. The investigators will use TMS to study the mechanisms of primidone and propranolol action in ET, EBCC paradigm to evaluate cerebellar dysfunction in ET patients and to show whether cerebellar dysfunction influences the effectiveness of propranolol and primidone. The investigators will clinically assess patients using The Essential Tremor Rating Assessment Scale (TETRAS) and the Scale for the Assessment and Rating of Ataxia (SARA) scales. Patients with ET will be studied prior to treatment with propranolol or primidone and re-tested 3-6 months after treatment initiation. On each visit, the investigators will clinically assess the patients and perform accelerometry, TMS measurements, and the eyeblink classical conditioning (EBCC) paradigm. The investigators hypothesize that in ET patients, baseline electrophysiological parameters will differ between responders and non-responders to propranolol and primidone and that propranolol and primidone will cause a different pattern of change in electrophysiological parameters among responders. It is hypothesized that cerebellar dysfunction will negatively correlate with patients' response to treatment.

Start: August 2017

RAD 1601: EDGE Radiosurgery for Intractable Essential Tremor and Tremor-Dominant Parkinson's Disease

To determine the efficacy of frameless Virtual Cone Radiosurgical Thalamotomy for medically refractory tremor resulting from either Essential Tremor or Tremor-Dominant Parkinson's Disease with the Fahn-Tolosa-Marin Tremor Rating Scale (FTMTRS) in patients who are not candidates for deep brain stimulation (DBS).

Start: December 2017

Deep Brain Stimulation Effects in Essential Tremor

Deep Brain Stimulation (DBS) is an effective therapy for patients with medically refractory essential tremor. However, DBS programming is not standardized and multiple clinic visits are frequently required to adequately control symptoms. The investigators aim to longitudinally record brain signals from patients using a novel neurostimulator that can record brain signals. The investigators 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.

Start: January 2020

Functional Neuroimaging Feedback for Focused Ultrasound Thalamotomy

Focused ultrasound for Essential Tremor is an FDA approved treatment performed by neurosurgeons at the Ohio State Center for Neuromodulation that utilizes ultrasound technology to create a lesion in the thalamus of Essential Tremor patients. In order to improve long term effectiveness and reduce potential for side effects, brain imaging may be used to examine the functional connectivity of certain brain networks during the procedure. In order to investigate functional connectivity changes with these long term goals in mind, in this study neuroimaging will be taken immediately before, immediately after, and 24 hours after the focused ultrasound procedure for 10 Essential Tremor patients. One series of neuroimaging will also be conducted for 20 healthy control subjects to serve as a comparison. This study will not introduce any risks above standard of care, and may lead to improved long term outcomes of patients undergoing the Focused Ultrasound procedure.

Start: September 2018

Long-Term Transcutaneous Stimulation and Essential Tremor: A PET Study

Essential tremor (ET) is the most common movement disorder in the United States and affects up to 5% of the population. ET patients experience involuntary shaking of the hands, head and/or voice that can range from mildly limiting to severely disabling. Treatment options are limited and there are currently no medications specifically designed to treat it, and medications that are prescribed to relieve tremors are often limited by either inadequate efficacy or intolerable side effects. A subset of essential tremor patients whose tremors are inadequately treated by medication choose to undergo deep brain stimulation (DBS) of the ventral intermediate thalamic nucleus. DBS has been shown to be highly effective for tremor suppression. However, DBS carries significant risks. As a result, a very small (less than 3%) percentage of essential tremor patients undergo DBS therapy. The medical technology company Cala Health has developed a wristband device (the Cala TWO) that offers individuals with essential tremor a novel non-pharmacological, non-invasive alternative, in the form of stimulation of peripheral nerves, to aid in hand tremor relief. This innovative form of therapy has the potential to have important health, quality of life, and economic benefits for essential tremor patients. The present pilot study (Aim 1) will assess the effectiveness of 3-month twice daily treatment with the Cala TWO device to aid in the relief of hand tremors in adult essential tremor subjects that have been approved to undergo deep brain stimulation surgery at Mayo Clinic - Rochester. This study is a prospective, within subject, non-significant risk study at Mayo Clinic - Rochester, enrolling approximately 20 subjects. A completely optional component of this study (Aim 2) is seeking to perform three standard PET/CT sessions on a subset of these subjects (n=10) at Mayo Clinic - Rochester to evaluate changes in brain metabolic activity as a result of 3 months treatment with the device. The first session would take place upon a subjects entry into the study (start of month 1) and prior to any treatment with the Cala device, a second the following day after a 40 minute treatment period with the Cala device, and a third session at the end of the third month. This study is a prospective, within subject, greater than minimum risk study.

Start: February 2019

The Motor Network in Essential Tremor: Mechanisms of Therapy

Essential tremor (ET) is among the most common movement disorders, and is the most prevalent tremor disorder. It is a progressive, degenerative brain disorder that results in increasingly debilitating tremor, and afflicts an estimated 7 million people in the US (2.2% of the population) and estimates from population studies worldwide range from 0.4% to 6.3%. ET is directly linked to progressive functional impairment, social embarrassment, and even depression. Intention (kinetic) tremor of the arms occurs in approximately half of ET patients, and is typically a slow tremor (~5-10Hz) that occurs at the end of a purposeful movement, and is insidiously progressive over many years. Based on direct and indirect neurophysiological studies, it has been suggested that a pathological synchronous oscillation in a neuronal network involving the ventral intermediate nucleus (Vim) of the thalamus, the premotor (PM), primary motor (M1) cortices, and the cerebellum, may result in the production of ET. In spite of the numerous therapeutic modalities available, 65% of those suffering from upper limb tremor report serious difficulties during their daily lives. Deep brain stimulation (DBS) has emerged as an effective treatment option for those suffering from medically refractory ET. The accepted target for ET DBS therapy is the Vim thalamus. Vim projects to PM, M1, and supplementary motor areas (SMA) and receives afferents from the ipsilateral cerebellum. Moreover, electrophysiological recordings from Vim during stereotactic surgery have identified "tremor cells" that synchronously discharge with oscillatory muscle activity during tremor. Clinical and computational findings indicate that DBS suppresses tremor by masking these "burst driver" inputs to the thalamus. The overall goal is to investigate the neural signatures of tremor generation in the thalamocortical network by recording data during DBS implantation surgery. Investigators will record data from the macroelectrode implanted in the Vim for DBS therapy, and through an additional 6-contact subdural cortical strip that will be placed on the hand motor cortical area temporarily through the same burr hole opened for the implantation of the DBS electrode.

Start: March 2016

Sensory Gating Measured With Microelectrode Recording (MER) During Deep Brain Stimulation (DBS) Surgery

Deep brain stimulation (DBS) is an FDA approved, and widely used method for treating the motor symptoms of Parkinson's disease (PD), Essential Tremor (ET), Dystonia and Obsessive Compulsive disorder (OCD). Over 100,000 patients worldwide have now been implanted with DBS devices. Current approved methods to locate the DBS target regions in the brain use a combination of stereotactic imaging techniques and measurements of the electrical activity of brain cells. As part of the standard clinical technique, electrical data are collected from individual nerve cells. The target brain region emits unique electrical signals. At certain brain locations, during DBS surgery, additional electrical data that are generated in response to sound will be collected. Regions of the brain that have a decreased response to repeated sound (auditory gating) may be important DBS targets for improving thinking. The aims are (i) during DBS surgery, in addition to EEG, use microelectrodes in the brain to find brain regions, along the normal path to the DBS target, where auditory gating occurs and then (ii) determine if stimulation of the identified region(s) alters auditory gating measured by EEG. Also an additional aim (iii) is to measure electrical activity at the scalp with EEG to characterize auditory gating in patients before and after DBS surgery and also a healthy control population.

Start: December 2014

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.

Start: March 2021

Investigating the Use of Complex Pulse Shapes for DBS in Movement Disorders

Parkinson's disease and essential tremor are chronic movement disorders for which there is no cure. When medication is no longer effective, deep brain stimulation (DBS) is recommended. Standard DBS is a neuromodulation method that uses a simple monophasic pulse, delivered from an electrode to stimulate neurons in a target brain area. This monophasic pulse spreads out from the electrode creating a broad, electric field that stimulates a large neural population. This can often effectively reduce motor symptoms. However, many DBS patients experience side effects - caused by stimulation of non-target neurons - and suboptimal symptom control - caused by inadequate stimulation of the correct neural target. The ability to carefully manipulate the stimulating electric field to target specific neural subpopulations could solve these problems and improve patient outcomes. The use of complex pulse shapes, specifically biphasic pulses and asymmetric pre-pulses, can control the temporal properties of the stimulation field. Evidence suggests that temporal manipulations of the stimulation field can exploit biophysical differences in neurons to target specific subpopulations. Therefore, our aim is to evaluate the effectiveness of complex pulse shapes to reduce side effects and improve symptom control in DBS movement patients.

Start: February 2019

Utilizing Smart Devices to Identify New Phenotypical Characteristics in Movement Disorders

This observational and experimental study seeks to establish a Smart Device System (SDS) to monitor high-resolution handtremor-based data using Smartphones, SmartWatches and Tablets. By doing this, movement data will be analyzed in depth with advanced statistical and Deep-Learning algorithms to identify new clinical phenotypical characteristics Parkinson's Disease and Essential Tremor.

Start: January 2019

A Second Magnetic Resonance Guided Focused Ultrasound Thalamotomy for Essential Tremor

This study will be a single-centre, prospective, single-arm, open-label, 12-week pilot trial assessing the safety and preliminary efficacy of a second MR-guided focused ultrasound (MRgFUS) thalamotomy on the naïve brain hemisphere after 48 weeks or more of the first MRgFUS thalamotomy in patients with medication-refractory ET. This study will be conducted at the Focused Ultrasound Centre of Excellence at Sunnybrook Health Sciences Centre/University of Toronto.

Start: October 2020

Wearable Sensor for Responsive DBS for ET

The purpose of this study is evaluate the effectiveness and safety of a possible new treatment for Essential Tremor (ET) using external wearable sensors, which have the capability of recording acceleration and Electromyography (EMG). This therapy is called Responsive Deep Brain Stimulation (R-DBS). R-DBS systems will communicate with a computer, and apply stimulation when the computer detects patterns associated with tremor. This detection will suppress pathological activity and improve or alleviate the tremor. Currently, DBS is approved for the treatment of ET; however, stimulation is delivered continuously even when tremor or other symptoms are absent. Continuous DBS can lead to unwanted side effects such as stuttering and gait\balance problems. On the other hand, R-DBS will turn on only if activity associated with ET from the external sensors is detected.

Start: September 2018

Demand-driven Management of Essential Tremor

This study evaluates the effectiveness of tremor control using various strategies for implementing demand-driven thalamic deep brain stimulation (DBS) for essential tremor. Therapeutic stimulation at the Vim nucleus of the thalamus will be initiated and modulated using signals derived from external sensors (e.g. EMG, accelerometer) and cortical or thalamic electrodes.

Start: February 2015

Brain Networks and Consciousness

General anesthesia (GA) is a medically induced state of unresponsiveness and unconsciousness, which millions of people experience every year. Despite its ubiquity, a clear and consistent picture of the brain circuits mediating consciousness and responsiveness has not emerged. Studies to date are limited by lack of direct recordings in human brain during medically induced anesthesia. Our overall hypothesis is that the current model of consciousness, originally proposed to model disorders and recovery of consciousness after brain injury, can be generalized to understand mechanisms of consciousness more broadly. This will be studied through three specific aims. The first is to evaluate the difference in anesthesia sensitivity in patients with and without underlying basal ganglia pathology. Second is to correlate changes in brain circuitry with induction and emergence from anesthesia. The third aim is to evaluate the effects of targeted deep brain stimulation on anesthesia induced loss and recovery of consciousness. This study focuses on experimentally studying these related brain circuits by taking advantage of pathological differences in movement disorder patient populations undergoing deep brain stimulation (DBS) surgery. DBS is a neurosurgical procedure that is used as treatment for movement disorders, such as Parkinson's disease and essential tremor, and provides a mechanism to acquire brain activity recordings in subcortical structures. This study will provide important insight by using human data to shed light on the generalizability of the current model of consciousness. The subject's surgery for DBS will be prolonged by up to 40 minutes in order to record the participant's brain activity and their responses to verbal and auditory stimuli.

Start: October 2020

Gamma Knife Radiosurgery for Treatment of Essential Tremor

The purpose of this study is to examine effects (good and bad) of gamma knife radiosurgery for essential tremor. The gamma knife places a small lesion in the brain to suppress tremors.

Start: September 2014

New Stereotactic Frame System for Neurosurgery

This study is designed to demonstrate an in-house developed re-attachable stereotactic system that can markedly reduce the overall deep brain stimulation (DBS) procedure time to greatly facilitate subject access to neurosurgical restorative therapies. Subjects will consist exclusively of individuals who have been approved to undergo deep brain stimulation surgery for the treatment of a neurological disorder at Mayo Clinic - Rochester MN. This study is a quantitative comparative, between-subject study enrolling approximately 10 subjects.

Start: May 2021

Alternating Current Stimulation for Essential Tremor

Movement disorders are common neurological disorders, characterized by either excess or paucity of movements. Essential tremor (ET) is one of the most common of these disorders, defined as chronic, rhythmic involuntary movements (tremor) that occur primarily during action involving the upper extremities as prominent body site. ET occurs in between 0.4% and 4% of adults below age 60, its prevalence and related impairment of routine daily actions increasing dramatically with age. More than half of patients do not regain functional independence with medications. These patients are offered functional neurosurgical approaches that carry procedural risk or adverse effects secondary to deep electric stimulation of surgical lesioning. Hence, there is a substantial need for alternative, non-invasive therapeutic options for this disabling neurological disorder. Recently, non-invasive neuromodulation applied as transcranial alternating current stimulation (tACS), has emerged as promising for tremor control. In healthy subjects, tACS applied with a high definition (or focused) montage to the primary motor cortex (M1), was found to entrain physiological tremor; in patients with Parkinson's disease, tACS could decrease the amplitude of rest tremor when the stimulation was delivered in phase with, and at the same frequency of, the tremor. Tremor in ET could also be entrained applying ACS to the arm skin's peripheral nerves (transcutaneous ACS), but its effect on tremor amplitude is unknown. METHODS AND POTENTIAL CONTRIBUTION/IMPACT OF THE RESEARCH. The proposed project aims to explore the whole potential of tACS for the tremor suppression in ET. The investigators aim to test the following hypotheses: focused (or high definition, HD) tACS delivered over M1 at the same frequency of the tremor is effective in decreasing tremor amplitude in ET; this effect is strongest when the delivery of tACS is locked to the phase of the tremor expressed by the patient, i.e. administering tACS in a closed-loop modality; transcutaneous ACS in the upper extremities is as effective as tACS applied to the scalp around M1.

Start: October 2020

Cortical-Basal Ganglia Speech Networks

In this research study the researchers want to learn more about brain activity related to speech perception and production.

Start: October 2020

Modulatory Effects of Deep Brain Stimulation on Cerebral Cortical Activity

The purpose of this study is to learn about how deep brain stimulation (DBS) affects brain activity in those with Parkinson's disease (PD) and essential tremor (ET). The effect of therapeutic and non-therapeutic stimulation settings will be assessed. Additionally, DBS effects in the presence and absence of anti-PD medication will be studied. Also of interest are differences in stimulation effects while at rest versus while performing a task.

Start: January 2020

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).

Start: August 2020