Essential tremor (ET) is a neurological isorder characterized by shaking of hands (and sometimes other parts of the body including the head), evoked by intentional movements. The exact incidence is unknown, but it is presumed to be the most common type of tremor and also the most commonly observed movement disorder. Essential tremor was also previously known as "benign essential tremor", but the adjective "benign" has been removed in recognition of the sometimes disabling nature of the disorder.