Experimental Therapeutics in Essential Tremor Using Cerebellar Transcranial Direct Current Stimulation

Inclusion Criteria: * Age ≥ 18 years and ≤ 65 years * Important essential tremor (bilateral postural and/or action tremor since more than one year) * Normal physical and neurological examination, except for essential tremor * Insufficient efficiency of usual essential tremor's treatment * No treatment altering the cortical excitability * Agreement to use a medically acceptable method of contraception throughout the study for female of childbearing potential * mini-mental status score \>24 Exclusion Criteria: * Age \< 18 years and \> 65 years * Current neurological or psychiatric illness other than essential tremor * Individual who is on medication which is known to lower seizure threshold * Previous history of seizure, loss of conciousness or current active epilepsy * Contraindication for MRI or TMS study * Intake of antiepileptic medications for essential tremor (barbiturates, gabapentine, topiramate, clonazepam), within the 7 days preceeding the first visit * alcohol intake within the 24 hours preceeding the first visit * Pregnancy, breast feeding women and women who are of childbearing age and not practicing adequate birth control * Individual who have MMS ≤ 24/30 or patients legally protected or inability to provide an informed consent * Simultaneous participation in another clinical trial * Patients who are not enrolled at social security