Essential Tremor

Abstract Essential tremor is a neurological syndrome consisting of bilateral upper extremity action tremor of at least three years duration, with or without tremor in other locations, most commonly the head and voice, and there are no other associated neurological abnormalities. Essential tremor plus is the classification used for patients meeting the criteria for essential tremor except for exhibiting other signs or symptoms of uncertain clinical significance. A complex additive polygenic heritability of at least 75% appears to underly most cases of essential tremor, and only a few rare Mendelian dominant mutations have been found. Patients with essential tremor may eventually develop other neurological signs of more complex tremor syndromes such as tremor-predominant parkinsonism, dystonic tremor, and tremor-ataxia. Propranolol, primidone and topiramate are the only medications with double-blind placebo-controlled proof of efficacy, which is inadequate in most patients with moderate-severe tremor. Stereotactic surgery is the most effective treatment, but many aspects of deep brain stimulation, magnetic resonance-guided focused ultrasound and radiosurgery are still investigational.