Update on essential tremor.

Essential tremor (ET) is one of the most common neurological disorders among adults, and is the most common tremor disorder. ET has classically been viewed as a benign monosymptomatic condition. Yet over the past 10 years, a growing body of evidence indicates that this is a progressive condition that is clinically heterogeneous, and may be associated with a variety of different features such as gait abnormalities, parkinsonism, cognitive impairment, dementia, personality disturbances, depressive symptoms, and sensory abnormalities (e.g., mild olfactory dysfunction and hearing impairment). In addition, postmortem studies are showing a pathologically heterogeneous neurodegenerative disease. The emerging view is that ET might be a family of diseases, unified by the presence of kinetic tremor, but further characterized by etiological, clinical and pathological heterogeneity. The diagnosis of ET is clinical and made by history and physical examination. Effective pharmacological treatments for the disorder currently remain limited. Drugs are generally initiated when the tremor begins to interfere with the patient's ability to perform daily activities or when the tremor becomes embarrassing. For severe, medically refractory ET, thalamic ventralis intermedius nucleus deep brain stimulation may lessen tremor and improve function.