Functional Imaging of Tremor Circuits and Mechanisms of Treatment Response
Essential TremorTremorEssential Tremor (ET) is the most common tremor disorder, currently affecting an estimated 2.9 million Americans and leading to disability and decreased quality of life in 75% of cases. The pathophysiology of ET is poorly understood, with the source of the tremor remaining controversial since all studies show increased activity in the cerebellum (including mimicked tremor in controls), while animal models of ET using harmaline and a single human PET study implicate the inferior olivary nucleus in the brainstem. There is evidence from the investigator's laboratory that the use of resting-state functional magnetic resonance imaging (rs-fMRI) is useful for characterizing the abnormal tremor neural network in ET compared with controls. The goal is to identify the source of the tremor, which is hypothesized to remain active during rest. Current ET diagnostic criteria require the presence of postural and/or kinetic tremor, which are assumed to be different manifestations of the same tremor oscillator. This long-standing assumption may be incorrect based on several lines of evidence from the investigator's laboratory, and has major implications for understanding ET pathophysiology and treatment. The investigators will test the hypothesis that postural and kinetic tremors are generated through different neural mechanisms. Treatment of ET focuses on pharmacological agents of various mechanisms and rarely deep brain stimulation of the Vim thalamus. Despite the assortment of agents used to treat ET, only ~50% of patients benefit from a particular agent. Furthermore, the mechanisms of action on tremor are not generally known. Understanding the mechanisms of action of various tremor-suppressing agents is critical for future drug development. In this proposal, the investigators plan to study the effects of ethanol (the most efficacious tremor-suppressant currently available) and propranolol (a non-specific β-adrenergic blocker with proven efficacy and unknown mechanism of action) on the tremor neural network.
Effects of High Amplitude and Focused tACS on Entraining Physiological Tremor
TremorLimbTranscranial alternating current stimulation (tACS) is a noninvasive neuromodulation method that works by passing alternating electric current between electrodes where at least one of them is attached to the head. While tACS applied over the motor cortex at the general applied amplitude (1 mA) and using patch electrodes has been shown to entrain physiological tremor in healthy volunteers, the aim of this study is to test the feasibility of using high-amplitude tACS and to assess the effect of different electrode montages and stimulation sites in entraining physiological tremor. First, 10 subjects (arm 1) will be stimulated with 2 mA current amplitude applied between saline soaked patch square electrodes and comparison will be done between motor cortex stimulation and peripheral cortex stimulation. Then, 10 subjects (arm 2) will be stimulated using focused 4x1 montage with gel-filled cup-electrodes and 5 mA amplitude and comparison will be made between motor cortex and occipital cortex stimulation. Three outcome measurements will be measured during the experiments which are: tremor entrainment, phosphene intensity and phosphene threshold.
Open-Label Trial of Sulforaphane in Premutation Carriers With FXTAS
Fragile X Associated Tremor/Ataxia Syndrome (Fxtas) (Diagnosis)FXTAS is a rare genetic progressive neurodegenerative disorder, linked to a trinucleotide repeat expansion in the FMR1 gene. FXTAS is characterized by tremor and ataxia in addition to atrophy and white matter disease in the central nervous system (CNS). In addition to the major clinical observations of intention tremor and gait dysfunction, minor symptoms of parkinsonism, neuropathy, and cognitive decline also significantly impact individuals with FXTAS. The dietary supplement being tested in this study is called Sulforaphane. It is found in broccoli and similar cruciferous vegetables and may cause some gas and discomfort. This is not a study looking at clinical efficacy but instead a study of molecular outcome measures. Investigators want to get more information about how Sulforaphane affects specific biomolecular markers captured in blood. In this study, participants will be taking an increasing amount of the Sulphoraphane supplement pills (238mg/tablet), starting at 1 and increasing to 6, every morning at breakfast for 6 months. In addition, there will be a total of 3 visits (Initial, 3-month and 6-month) to the MIND Institute where participants will be evaluated. At each visit (3 total) participants will undergo a battery of medical and neurologic exams which make take 2-3 days to complete each time. Participants and/or their caregivers will also be asked to fill out questionnaires/surveys. At the initial visit and at 6 months, we will collect blood for analysis. Two MRI scans will be done, also at the initial visit and at 6 months.
Trans-spinal Direct Current Stimulation in Primary Orthostatic Tremor
Primary Orthostatic TremorTo explore the effect of cathodal tsDCS vs sham tsDCS in primary orthostatic tremor. The investigators hypothesize that cathodal tsDCS but not sham tsDCS would be able to restore both motor and sensory pathways of the spinal cord leading to functional improvements.
RECHARGE Sub-Study to the Implantable Systems Performance Registry (ISPR)
Parkinson's DiseaseEssential Tremor1 moreThe purpose of this study is to assess the recharge feature of the Activa RC System in patients who are receiving Deep Brain Stimulation (DBS) for Parkinson's Disease (PD), Essential Tremor (ET), or dystonia.
Experimental Therapeutics in Essential Tremor Using Transcranial Direct Current Stimulation
Essential TremorThe purpose of this study is to determine whether transcranial direct current stimulation (tDCS) delivered over the motor cortex or the cerebellum can improve essential tremor and to identify the cerebral mechanisms involved in these potential effects.
Kinematic-based BoNT-A Injections for Bilateral ET
Essential TremorThe primary objective is to study the efficacy of botulinum toxin type A (Xeomin®) injected utilizing kinematically-based injection parameters for the treatment of upper extremity essential tremor (ET). Additional objectives are to study the benefit of kinematic assessment tools in determining injection parameters and to study the composition of tremor using kinematics.
MRI Guided Focused Ultrasound for Tremor in Multiple Sclerosis
Multiple SclerosisThis project goal is to explore the option of (MRgFUS) as a treatment for tremor in MS patients with disabling refractory tremor.
The Study of Rest Tremor Suppression by Using Electrical Muscle Stimulation
Rest TremorParkinson's DiseaseThis study is aimed to study the safety and feasibility of electrical muscle stimulation (EMS) in suppression of tremor from various causes especially for rest tremor in Parkinson's disease.
Relief From Side Effects: Clinical Use of Electrodes With Direction
Deep Brain StimulationDirectional Lead1 moreDeep Brain Stimulation (DBS) uses electrical pulses sent through a lead (insulated wire) to help stop unwanted symptoms in a variety of brain diseases, including the tremor seen in patients with Essential Tremor (ET). The current standard lead allows this stimulation to spread out uniformly in all directions. As these diseases progress, however, the amount of electrical stimulation required to stop the symptom usually increases. This may become problematic because the increased electrical stimulation required for advanced symptoms may spread outside the desired targeted area, and effect other parts of the brain and causing unwanted side effects. A new type of DBS lead has been developed which can steer, or focus, the electrical stimulation in a given direction toward the desired target area and away from areas that would cause side effects. We would like to quantify the benefit seen in patients who have been switched from the traditional lead to this new directional lead.