Patient description: A 22-year-old Caucasian man came to the Clinic with a history of tremors since a year ago. The tremor was first in his right hand while holding something. Later the tremor became continuous and extended to both hands and legs and even at rest. The Kayser-Fleischer' ring was detected in the ophthalmologic exam. The physical exam revealed jaundice, hepatosplenomegaly and hypotonia of the upper limbs. He had a constant smile on his face, however, he has aggressive behavior according to his parents' explanation. His laboratory study was significant for a low serum caeruloplasmin (0.05 g/l), and a raised 24 hour urine copper excretion (120 μg/24 h). Wilson disease was confirmed by high liver copper concentration (305 μg/g dry weight of liver).

Clinical trial eligibility criteria: eligible ages (years): 18.0-80.0,  Essential Tremor for ET subjects: 1. Outpatients with essential tremor as diagnosed and confirmed by movement disorder specialist 2. Women of child-bearing potential must provide a negative pregnancy test at entry into the study 3. Stable doses of all medications for at least 14 days prior to study entry and for the duration of the study, 4. At least a 1cm amplitude tremor as judged by the screener using a ruler for Healthy Volunteers: 1. Healthy subjects without tremor and without significant neurologic disease suggestive of cerebellar ataxia or other neurodegenerative diseases 2. Ages 18-80  Any unstable illness or concomitant medical condition that, in the investigator's opinion, precludes participation in this study, including disorders that may affect gait or balance (i.e., stroke, arthritis, etc). 2. Pregnancy or lactation. 3. Concurrent participation in another clinical study. 4. Dementia or other psychiatric illness that prevents the patient from giving informed consent (Montreal Cognitive Assessment Score score less than or equal to 21). 5. Legal incapacity or limited legal capacity. 6. Tremor derived from any cause other than essential tremor (Parkinson's disease, drug-induced, anxiety-induced) in the clinical assessment at screening 7. Currently taking lithium or amiodarone or any other drug judged to be contributing to tremor as judged by the investigator (may be a cause of tremor) 8. No medication is an absolute from TMS. Medications will be reviewed by the responsible MD and a decision about will be made based on the following The patient's past medical history, drug dose, history of recent medication changes or duration of treatment, and combination with other Central Nervous System active drugs The published TMS guidelines review of medications to be considered with TMS 9. History of seizures, diagnosis of epilepsy, history of abnormal (epileptiform) EEG, or family history of treatment resistant epilepsy with the exception of a single seizure of benign etiology (e.g. febrile seizures) in the judgement of the investigator 10. TMS and MRI-Specific including Known metal in the head (such as a surgical aneurysm clip) or a history of prior neurosurgical procedures Ferromagnetic bioimplants activated by any electronic, mechanical or magnetic means, such as cochlear implants, pacemakers, medication pumps, vagal stimulators, deep brain stimulators, neurostimulators, biostimulators, or ventriculo-peritoneal shunts Subjects who have or might have bullet fragments or other shrapnel (veterans or workers exposed to metal in their work environment) Subjects with metallic paint (e.g. color contact lenses, tattoos, metallic eyeliner) Subjects expressing significant claustrophobia