The National Institute of Neurological Disorders and Stroke, part of the National Institutes of Health, is looking for individuals to participate in clinical studies. Participating in clinical trials allows you to play an active role in research on the nature and causes of many disorders of the brain and nervous system, and to possibly help physician-scientists develop future treatments. The information below is designed to help you quickly learn about actively recruiting research studies for which you or someone you know may be eligible.


Objectives: To explore a neurophysiological difference between patients with essential tremor (ET) and dystonic tremor (DT). Sample Size and Population: We plan to recruit 26 healthy volunteers (HVs), 26 patients with ET, 26 patients with dystonic tremor from the Movement Disorders and Botulinum Toxin (BoNT) clinics of HMCS. The dystonic tremor group will be divided into 2 subgroups: pure dystonic tremor (pDT), patients who have dystonia and tremor in the same limb, tremor associated with dystonia (TAWD), patients who have isolated tremor with dystonia elsewhere. We plan to enroll 13 patients with pDT and 13 with TAWD. We plan to recruit a total of 20 participants including patients with ET, DT and HVs if the use of data from protocol 10-N-0009 is permitted. All neurophysiologic results will be compared between patients and HVs. Design: Subjects will come to NIH for at least one study visit. All subjects will undergo a screening visit including taking a medical history and physical examination. Then the patients will be scored clinically for tremor in both ET and DT and dystonia only for DT. All subjects will have a series of transcranial magnetic stimulation (TMS) studies. TMS-induced electromyographic (EMG) activity of hand and forearm muscles will be recorded as motor evoked potentials (MEPs). Pyramidal threshold will be determined by inion stimulation. Then, paired-pulse stimulation at the cerebellum followed by the motor cortex will be performed at rest and at tonic activation of the hand muscle. Only patients will have recordings of tremor at rest, postural holding, and with action and specific tasks such as writing by using accelerometry and EMG. Additionally, a single TMS will be delivered to the motor cortex or cerebellum while the patients elicit their tremor in order to explore the effect of TMS on tremor. All subjects (both HVs and ET, DT) will be tested for their threshold to discriminate somatosensory stimulation and for their performance of quick ballistic movements. All subjects will also undergo a magnetic resonance imaging (MRI) study which includes structural MRI, resting state functional MRI (rsfMRI), diffusion tensor imaging (DTI), MR spectroscopy. The subjects can either undergo the MRI study on the same visit as the other parts of experiment or do it separately. Outcome measurements: The various neurophysiological results include the data from the TMS experiment, tremor analysis, threshold of temporal discrimination, ballistic movement and MRI experiment. These results will be compared between HVs and patients group.

Eligibility Criteria:

- INCLUSION CRITERIA: - Must be 18 years or older - Fulfill the diagnostic criteria of essential tremor, pure dystonic tremor and tremor associated dystonia, as defined by the Consensus Statement of the Movement Disorder Society on Tremor, 1998. We will recruit patients displaying hand tremors in each group as the follows: - Hand tremor patients in ET group. - Dystonic hand tremor patients in pDT group. - Cervical dystonia (CD) patients or spasmodic dysphonia and hand tremor without clinical evidence of hand dystonia in TAWD group. - For HVs only: absence of dystonia or other neurological disorder with any effect on the motor or sensory systems. - Ability to give informed consent. - Ability to comply with all study procedures, based on the judgment by the investigator(s). - Agree to not drink caffeine or alcohol for 48 hours before participating in the protocol. EXCLUSION CRITERIA: Either of the following will exclude patients from the study: - Secondary forms of dystonia and tremor, including tardive dyskinesia. - Botulinum toxin treatment

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