Essential tremor then and now: How views of the most common tremor diathesis have changed over time

Background Essential tremor (ET) is the most prevalent tremor diathesis. In this “then” and “now” piece, I detail how views of this disorder have changed over time. Methods A PubMed search was conducted on June 15, 2017. The term “essential tremor” was crossed in sequential order with 14 s search terms (e.g., genetics, clinical). Results The traditional view of ET was that it was monosymptomatic. An emerging view of ET is as a more clinically-complex entity with a range of possible motor and non-motor features. Traditionally, ET was viewed as autosomal dominant with complete penetrance by age 65. Current thinking is that, in addition to monogenic forms of ET, the disease is likely to be complex, with incomplete penetrance into advanced age. While non-genetic factors were traditionally presumed to exist, epidemiological studies have explored several potential environmental toxicants. The traditional olivary model of ET posited the existence of a central oscillator; an alternative is the cerebellar degenerative model, which is now under consideration. Conclusions For ET, there is clearly a “then” and “now” when one assesses changes in our understanding of the disease with time. Indeed, concepts relating to the clinical features, disease etiology and pathogenesis have all changed substantially.