Transcranial Stimulation for Essential Tremor

Inclusion Criteria 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

Inclusion Criteria 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

Exclusion Criteria:

1. 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 exclusion from TMS. Medications will be reviewed by the responsible MD and a decision about inclusion 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 exclusion criteria 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.