rTMS Therapy for Primary Orthostatic Tremor

Primary orthostatic tremor(POT) is a rare progressive functionally disabling tremor disorder. The characteristic features of POT are symptoms of unsteadiness in legs reported by patients when they are standing and improvement of symptoms upon walking and sitting. Due to the limited success of other treatment options there is a clear merit in continuing efforts to explore and investigate novel treatment modalities. Transcranial magnetic stimulation (TMS) is a well-established physiological tool to understand brain function. When repetitious TMS pulses are delivered to a specific target at predefined stimulation parameters, it is referred to as rTMS therapy.The investigators propose a novel approach to investigate the clinical and physiological effects of low frequency rTMS therapy in POT. The overarching hypothesis of this study is that low frequency rTMS therapy delivered to the cerebellum will modulate the cerebellar excitability and result in clinical improvements.In order to determine the physiological effects related to rTMS, the tremor physiology will also be recorded with surface electromyography (EMG). The investigator will also record the changes in cerebellum excitability in response to rTMS using cerebello-cortical inhibition (CBI), a well-established TMS parameter.