Is essential tremor a single entity?

Essential tremor (ET) is a frequent movement disorder. The new tremor classification has subdivided ET into the classical form with bilateral action tremor of the hands with or without involvement of further tremor locations and without any other explaining signs or symptoms for the tremor and into ET plus' which comes additionally with further neurological signs of unknown origin. This will provide a better foundation for subclassifying the condition. The immediate cause of ET is a preformed oscillating network within the central nervous system as revealed with electrophysiological methods. The reason why this network is getting into the tremor mode is unclear. Pathology has so far not convincingly proved neurodegeneration for the condition but possibly adaptive changes of the brain particularly in the cerebellum are likely. Genetics have not yet provided insight into the molecular causes of the condition but several genetic diseases presenting with an ET syndrome have been uncovered. Treatment options cover medication (propranolol, primidone, topiramate) and surgical interventions with deep brain stimulation, gamma-knife surgery and the recently introduced magnetic resonance imaging guided focused ultrasound lesioning. Further progress is awaited from the better integration of large prospective cohort assessment and basic science studies on the possible etiologies. In particular, aging-related tremor may explain a large number of the patients seen in clinical practice. Currently ET is considered a clinically relatively uniform condition with presumably various underlying etiologies.