Essential tremor

Essential tremor (ET) is a neurological disorder that is considered to be one of the most common adult-onset movement disorders. ET is typically characterized by rhythmic, involuntary shaking of one or more parts of the body, and occurs exclusively during voluntary movements (action tremor) or in positions against gravity (postural tremor). The phenotypic severity of ET is variable, as evidenced by the existence of both highly disabling and milder forms of the disease. There are three subtypes of ET, namely hereditary, sporadic, and senile, and most studies indicate that ET is a hereditary disorder in more than half of affected individuals (and presumably has autosomal-dominant inheritance). The diagnostic approach includes obtaining a history, physical examination, and laboratory tests. At present, there are no validated serologic, radiologic, or pathological markers.