Essential tremor: clinical characteristics.

Essential tremor (ET) is the most common movement disorder. However, only a small percentage of people affected by this genetically transmitted neurologic disorder seek medical attention. Lack of consensus on the diagnostic criteria for ET is an impediment to accurate diagnosis and leads to difficulty in accessing accurate prevalence data. Although a positive family history, alcohol sensitivity, and propranolol responsiveness are characteristic of ET, these factors should not be considered necessary for the diagnosis of ET. ET can produce substantial physical and psychosocial disabilities. The occasional coexistence of ET and Parkinson's disease (PD) in the same individual may present a diagnostic challenge.