Scientists watch tremors up close to unlock brain secrets

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

* INCLUSION CRITERIA FOR TREMOR PATIENTS: * Patients diagnosed with a tremor syndrome, including, but not limited to * Essential tremor (per definition of the Tremor Research Group) * Parkinson disease (per UK Brain Bank criteria) * Focal tremor such as isolated head tremor, voice tremor * Task-specific tremor such as primary writing tremor * Orthostatic tremor * Patients with other tremor syndromes such as dystonic tremor, intention tremor, etc. * Age 18 or older * Able to give informed consent * Agree to not drink caffeine or alcohol for 12 hours before phenotyping and selected sub-study visits because both agents can modify brain activity and may confound outcome measures. INCLUSION CRITERIA FOR HEALTHY VOLUNTEERS: * Age 18 or older. * Able to give informed consent. * Agree to not consume caffeine or alcohol for 12 hours before selected sub-study visits because both agents may modify the activity of the brain during the study. EXCLUSION CRITERIA FOR TREMOR PATIENTS: * Problematic alcohol use, as defined by a score of 8 or higher on the WHO Alcohol Use Disorders Identification Test (AUDIT). * History of a brain tumor, a stroke, traumatic brain injury, epilepsy or a history of seizures. * History of psychotic disorder, Bipolar Disorder or a current depressive episode. * History or clinical evidence of another neurologic disorder than a tremor syndrome as defined above, which may interfere with the ability to comply with protocol requirements or interpret the obtained results. EXCLUSION CRITERIA FOR HEALTHY VOLUNTEERS: * Have abnormal findings of clinical significance on the neurological examination that may affect the scientific integrity of the study * Problematic alcohol use, as defined by a score of 8 or higher on the WHO Alcohol Use Disorders Identification Test (AUDIT) * History of a brain tumor, a stroke, traumatic brain injury, epilepsy or a history of seizures. * History of psychotic disorder, Bipolar Disorder or a current depressive episode. ADDITIONAL EXCLUSION CRITERIA FOR MOVEMENT DISORDER PATIENTS AND HEALTHY VOLUNTEERS SPECIFICALLY FOR MRI: We will follow the NMR Center guidelines for MR safety. Some of the exclusions are: * Have non-MRI compatible metal in the body, such as a cardiac pacemaker, brain stimulator, shrapnel, surgical metal, clips in the brain or on blood vessels, cochlear implants, artificial heart valves or ferromagnetic fragments in the eye or oral cavity as these make having an MRI unsafe. * Unable to lie flat on the back for the expected length of the experiment. * Have uncontrolled movements of the head. * Have an abnormality on the brain imaging or neurologic examination not related to the diagnosis. * Uncomfortable being in a small space for the expected length of the experiment. * Non-removable body piercing or tattoo posing MRI risk * Pregnancy. ADDITIONAL EXCLUSION CRITERIA FOR TREMOR PATIENTS AND HEALTHY VOLUNTEERS FOR TMS AND MRI: * Ferromagnetic metal in the cranial cavity or eye, e.g. aneurysm clip or ocular foreign body. * Implanted electronic device including deep brain stimulation systems.