Assessing Clinical Effectiveness of Cerebellar Repetitive Transcranial Magnetic Stimulation (rTMS) on Severity of Motor Signs of Essential Tremor

Essential tremor (ET) is a low-mortality, though truly burdensome and debilitating condition which is known to be the second most common movement disorder of the adult population only after restless legs syndrome. The prevalence of the disorder in all age groups has been estimated to be 0.9%. Repetitive transcranial magnetic stimulation (rTMS) is an almost safe technique which has been used in diagnosis and treatment of many neurologic and psychiatric conditions. Recent studies have shown that cerebellum has a significant role in development of ET and that rTMS could exert therapeutic effects on its motor symptoms. In this study researchers will recruit at least 30 subjects among patients visiting at the Specialty Clinic of Mashhad Medical University according to researchers exclusion and inclusion criteria and after signing a written informed consent, will randomly be assigned to either real or sham rTMS. On the real rTMS arm, patients will be treated with 900 pulses of 1 Hz rTMS on 90% of resting motor threshold (RMT) delivered over each cerebellar hemisphere for 5 consecutive days and sham treatment will be performed with the same protocol using a small device placed on the TMS coil (not visible to the patients) producing electrical stimulation (less than 3 mili amperes), to simulate the sensation of real TMS. Subject's ear will be protected with earplugs during both real and sham stimulations. After 2 months of follow-up, patients will undergo crossover and receive the other treatment as described above. Patients would be assessed using Fahn-Tolosa-Marin scale at the baseline and again on days 5, 12, and 30 after each real or sham treatment session by a blinded researcher. Data will be analysed by another researcher who is also blind.